40 CFR 434.22 - Effluent limitation guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2013 CFR

2013-07-01

... consecutive days Concentration in mg/l Iron, total 7.0 3.5 Manganese, total 4.0 2.0 TSS 70 35 pH 1 1 1 Within... if discharges from such point sources normally exhibit a pH of less than 6.0 prior to treatment: BPT... practicable control technology currently available if discharges from such point sources normally exhibit a pH...

40 CFR 434.22 - Effluent limitation guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2012 CFR

2012-07-01

... consecutive days Concentration in mg/l Iron, total 7.0 3.5 Manganese, total 4.0 2.0 TSS 70 35 pH 1 1 1 Within... if discharges from such point sources normally exhibit a pH of less than 6.0 prior to treatment: BPT... practicable control technology currently available if discharges from such point sources normally exhibit a pH...

Asymptotic analysis of corona discharge from thin electrodes

NASA Technical Reports Server (NTRS)

Durbin, P. A.

1986-01-01

The steady discharge of a high-voltage corona is analyzed as a singular perturbation problem. The small parameter is the ratio of the length of the ionization region to the total gap length. By this method, current versus voltage characteristics can be calculated analytically.

Estimation of total discharged mass from the phreatic eruption of Ontake Volcano, central Japan, on September 27, 2014

NASA Astrophysics Data System (ADS)

Takarada, Shinji; Oikawa, Teruki; Furukawa, Ryuta; Hoshizumi, Hideo; Itoh, Jun'ichi; Geshi, Nobuo; Miyagi, Isoji

2016-08-01

The total mass discharged by the phreatic eruption of Ontake Volcano, central Japan, on September 27, 2014, was estimated using several methods. The estimated discharged mass was 1.2 × 106 t (segment integration method), 8.9 × 105 t (Pyle's exponential method), and varied from 8.6 × 103 to 2.5 × 106 t (Hayakawa's single isopach method). The segment integration and Pyle's exponential methods gave similar values. The single isopach method, however, gave a wide range of results depending on which contour was used. Therefore, the total discharged mass of the 2014 eruption is estimated at between 8.9 × 105 and 1.2 × 106 t. More than 90 % of the total mass accumulated within the proximal area. This shows how important it is to include a proximal area field survey for the total mass estimation of phreatic eruptions. A detailed isopleth mass distribution map was prepared covering as far as 85 km from the source. The main ash-fall dispersal was ENE in the proximal and medial areas and E in the distal area. The secondary distribution lobes also extended to the S and NW proximally, reflecting the effects of elutriation ash and surge deposits from pyroclastic density currents during the phreatic eruption. The total discharged mass of the 1979 phreatic eruption was also calculated for comparison. The resulting volume of 1.9 × 106 t (using the segment integration method) indicates that it was about 1.6-2.1 times larger than the 2014 eruption. The estimated average discharged mass flux rate of the 2014 eruption was 1.7 × 108 kg/h and for the 1979 eruption was 1.0 × 108 kg/h. One of the possible reasons for the higher flux rate of the 2014 eruption is the occurrence of pyroclastic density currents at the summit area.

Effect of anode oxide films on glow discharge spatial structure

NASA Astrophysics Data System (ADS)

Gulamov, E. N.; Islamov, R. S.; Zabelin, Alexandre M.

1994-04-01

A self-consistent calculation of voltage fall on the anode film as a function of its resistance has been performed in the presence of anode current spots under elevated-pressure glow discharge in nitrogen and N2:He equals 1:1 mixture. It has been shown that resistance of anode oxide films in industrial lasers with continuous copper anode can reach the values when total suppression of anode current structures takes place.

extrap: Software to assist the selection of extrapolation methods for moving-boat ADCP streamflow measurements

NASA Astrophysics Data System (ADS)

Mueller, David S.

2013-04-01

Selection of the appropriate extrapolation methods for computing the discharge in the unmeasured top and bottom parts of a moving-boat acoustic Doppler current profiler (ADCP) streamflow measurement is critical to the total discharge computation. The software tool, extrap, combines normalized velocity profiles from the entire cross section and multiple transects to determine a mean profile for the measurement. The use of an exponent derived from normalized data from the entire cross section is shown to be valid for application of the power velocity distribution law in the computation of the unmeasured discharge in a cross section. Selected statistics are combined with empirically derived criteria to automatically select the appropriate extrapolation methods. A graphical user interface (GUI) provides the user tools to visually evaluate the automatically selected extrapolation methods and manually change them, as necessary. The sensitivity of the total discharge to available extrapolation methods is presented in the GUI. Use of extrap by field hydrographers has demonstrated that extrap is a more accurate and efficient method of determining the appropriate extrapolation methods compared with tools currently (2012) provided in the ADCP manufacturers' software.

[Quality of hospital discharge reports in terms of current legislation and expert recommendations].

PubMed

Zambrana-García, José Luis; Rivas-Ruiz, Francisco

2013-01-01

To determine the quality of hospital discharge reports (HDRs) taking into account current legislation and the conclusions of the consensus on hospital discharge reports in medical specialities in 11 community hospitals in Andalusia (Spain). A cross-sectional study of 1,708 HDRs was carried out. We determined the presence or absence of the various items required by current legislation and by the recommendations of the above-mentioned consensus. A total of 97.4% (95% confidence interval [95% CI]: 96.5-98.2) of the HDRs were classified as satisfactory according to the stipulations of current legislation. However, when the assessment was based on the consensus, the rate of adequacy fell to 72.1% (95% CI: 70.0-74.3). A notable finding was the absence of the duration of treatment after hospital discharge in 39.4% of the HDRs. HDRs show an excellent level of compliance with the data required by current regulations, but their intrinsic quality needs to be improved. Copyright © 2012 SESPAS. Published by Elsevier Espana. All rights reserved.

Taser X26 discharges in swine: ventricular rhythm capture is dependent on discharge vector.

PubMed

Valentino, Daniel J; Walter, Robert J; Dennis, Andrew J; Margeta, Bosko; Starr, Frederic; Nagy, Kimberly K; Bokhari, Faran; Wiley, Dorion E; Joseph, Kimberly T; Roberts, Roxanne R

2008-12-01

Data from our previous studies indicate that Taser X26 stun devices can acutely alter cardiac function in swine. We hypothesized that most transcardiac discharge vectors would capture ventricular rhythm, but that other vectors, not traversing the heart, would fail to capture the ventricular rhythm. Using an Institutional Animal Care and Use Committee (IACUC) approved protocol, four Yorkshire pigs (25-36 kg) were anesthetized, paralyzed with succinylcholine (2 mg/kg), and then exposed to 10 second discharges from a police-issue Taser X26. For most discharges, the barbed darts were pushed manually into the skin to their full depth (12 mm) and were arranged in either transcardiac (such that a straight line connecting the darts would cross the region of the heart) or non-transcardiac vectors. A total of 11 different vectors and 22 discharge conditions were studied. For each vector, by simply rotating the cartridge 180-degrees in the gun, the primary current-emitting dart was changed and the direction of current flow during the discharge was reversed without physically moving the darts. Echocardiography and electrocardiograms (ECGs) were performed before, during, and after all discharges. p values < 0.05 were considered significant. ECGs were unreadable during the discharges because of electrical interference, but echocardiography images clearly demonstrated that ventricular rhythm was captured immediately in 52.5% (31 of 59) of the discharges on the ventral surface of the animal. In each of these cases, capture of the ventricular rhythm with rapid ventricular contractions consistent with ventricular tachycardia (VT) or flutter was seen throughout the discharge. A total of 27 discharges were administered with transcardiac vectors and ventricular capture occurred in 23 of these discharges (85.2% capture rate). A total of 32 non-transcardiac discharges were administered ventrally and capture was seen in only eight of these (25% capture rate). Ventricular fibrillation (VF) was seen with two vectors, both of which were transcardiac. In the remaining animals, VT occurred postdischarge until sinus rhythm was regained spontaneously. For most transcardiac vectors, Taser X26 caused immediate ventricular rhythm capture. This usually reverted spontaneously to sinus rhythm but potentially fatal VF was seen with two vectors. For some non-transcardiac vectors, capture was also seen but with a significantly (p < 0.0001) decreased incidence.

Feasibility of Estimating Constituent Concentrations and Loads Based on Data Recorded by Acoustic Instrumentation

USGS Publications Warehouse

Lietz, A.C.

2002-01-01

The acoustic Doppler current profiler (ADCP) and acoustic Doppler velocity meter (ADVM) were used to estimate constituent concentrations and loads at a sampling site along the Hendry-Collier County boundary in southwestern Florida. The sampling site is strategically placed within a highly managed canal system that exhibits low and rapidly changing water conditions. With the ADCP and ADVM, flow can be gaged more accurately rather than by conventional field-data collection methods. An ADVM velocity rating relates measured velocity determined by the ADCP (dependent variable) with the ADVM velocity (independent variable) by means of regression analysis techniques. The coefficient of determination (R2) for this rating is 0.99 at the sampling site. Concentrations and loads of total phosphorus, total Kjeldahl nitrogen, and total nitrogen (dependent variables) were related to instantaneous discharge, acoustic backscatter, stage, or water temperature (independent variables) recorded at the time of sampling. Only positive discharges were used for this analysis. Discharges less than 100 cubic feet per second generally are considered inaccurate (probably as a result of acoustic ray bending and vertical temperature gradients in the water column). Of the concentration models, only total phosphorus was statistically significant at the 95-percent confidence level (p-value less than 0.05). Total phosphorus had an adjusted R2 of 0.93, indicating most of the variation in the concentration can be explained by the discharge. All of the load models for total phosphorus, total Kjeldahl nitrogen, and total nitrogen were statistically significant. Most of the variation in load can be explained by the discharge as reflected in the adjusted R2 for total phosphorus (0.98), total Kjeldahl nitrogen (0.99), and total nitrogen (0.99).

Experimental Investigation of Electron Cloud Containment in a Nonuniform Magnetic Field

NASA Technical Reports Server (NTRS)

Eninger, J. E.

1974-01-01

Dense clouds of electrons were generated and studied in an axisymmetric, nonuniform magnetic field created by a short solenoid. The operation of the experiment was similar to that of a low-pressure (approximately 0.000001 Torr) magnetron discharge. Discharge current characteristics are presented as a function of pressure, magnetic field strength, voltage, and cathode end-plate location. The rotation of the electron cloud is determined from the frequency of diocotron waves. In the space charge saturated regime of operation, the cloud is found to rotate as a solid body with frequency close to V sub a/phi sub a where V sub a is the anode voltage and phi suba is the total magnetic flux. This result indicates that, in regions where electrons are present, the magnetic field lines are electrostatic equipotentials (E bar, B bar = 0). Equilibrium electron density distributions suggested by this conditions are integrated with respect to total ionizing power and are found consistent with measured discharge currents.

PHASE DIFFERENTIAL INDICATING CIRCUIT

DOEpatents

Kirsten, F.A.

1962-01-01

An electronic circuit for totalizing the net phase difference between two alternating current signals is designed which responds to both increasing and decreasing phase changes. A phase comparator provldes an output pulse for each 360 deg of phase difference occurring, there being a negative pulse for phase shtft in one direction and a positive pulse for a phase shift in the opposite direction. A counting circuit utilizing glow discharge tubes receives the negative and positive pulses at a single input terminal and provides a running net total, pulses of one polarity dded and pulses of the opposite polarity being subtracted. The glow discharge tubes may be decaded to increase the total count capacity. (AEC)

Laser-guided, intersecting discharge channels for the final beam transport in heavy-ion fusion

NASA Astrophysics Data System (ADS)

Niemann, C.; Neff, S.; Tauschwitz, A.; Penache, D.; Birkner, R.; Constantin, C.; Knobloch, R.; Presura, R.; Rosmej, F. B.; Hoffmann, D. H. H.; Yu, S. S.

2003-06-01

Ion-beam transport in space charge neutralizing discharge channels has been proposed for the final focus and chamber transport in a heavy-ion fusion reactor. A driver scenario with two-sided target illumination requires a system of two intersecting discharges to transport beams of the same charge from opposite sides towards the fusion target. In this article we report on experiments on the creation of free-standing, intersecting high-current discharge channels. The discharges are initiated in ammonia gas (NH3) in a metallic chamber by two perpendicular CO2-laser beams, which resonantly heat and subsequently rarefy the gas along the laser paths before the breakdown. These low density channels guide the discharges along the predefined paths and also around the 90° angles without any mechanical guiding structures. In this way stable X-, T-, and L-shaped discharges with currents in excess of 40 kA, at pressures of a few mbar were created with a total length of 110 cm. An 11.4 A MeV 58Ni+12 beam from the UNILAC (Universal Linear Accelerator) linear accelerator was used to probe the line-integrated ion-optical properties of the central channel in a T-shaped discharge.

Characterization of stormwater discharges from Las Flores Industrial Park, Rio Grande, Puerto Rico, 1998-99

USGS Publications Warehouse

Rodriguez, Jose M.

2000-01-01

Stormwater discharges from Las Flores Industrial Park, Rio Grande, Puerto Rico, were characterized from June 1998 to July 1999 by measuring the flow rate at two outfalls, delineating the drainage areas for each outfall, and calculating the volume of the stormwater discharges. Stormwater-discharge samples were collected and analyzed to determine the quality of the discharges. Constituent loads and loads per area were estimated for each drainage area. The studied drainage subareas covered approximately 46 percent of the total area of the Las Flores Industrial Park. Industrial groups represented in the study areas include manufacturers of textile, electronics, paper, fabricated metal, plastic, and chemical products. The concentrations of oil and grease (1 to 6 milligrams per liter), biochemical oxygen demand (4.7 to 16 milligrams per liter), total organic carbon (5.8 to 36 milligrams per liter), total suspended solids (28 to 100 milligrams per liter), and total phosphorous (0.11 to 0.78 milligrams per liter) from all the samples collected were less than the U.S. Environmental Protection Agency stormwater benchmark concentrations. Concentrations of chemical oxygen demand (15.8 to 157 milligrams per liter) and nitrate and nitrite (0.06 to 1.75 milligrams per liter) exceeded benchmark concentrations at one of the studied drainage areas. Total Kjeldahl nitrogen concentrations (1.00 to 3.20 milligrams per liter) exceeded the benchmark concentrations at the two studied drainage areas. Maximum concentrations for oil and grease, biochemical oxygen demand, chemical oxygen demand, total organic carbon, total Kjeldahl nitrogen, nitrate plus nitrite, and total phosphorous were detected in an area where electronics, plastics, and chemical products are currently manufactured. The maximum concentration of total suspended solids was detected at an area where textile, paper, plastic, chemical, and fabricated metal products are manufactured.

Electric thruster research

NASA Technical Reports Server (NTRS)

Kaufman, H. R.; Robinson, R. S.

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. 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. Thermal losses were calculated for an oxide-free hollow cathode. At low electron emissions, the total of the radiation and conduction losses agreed with the total discharge power. At higher emissions, though, the plasma collisions external to the cathode constituted an increasingly greater fraction of the discharge power. Experimental performance of a Hall-current thruster was adversely affected by nonuniformities in the magnetic field, produced by the cathode heating current. The technology of closed-drift thrusters was reviewed. The experimental electron diffusion in the acceleration channel was found to be within about a factor of 3 of the Bohm value for the better thruster designs at most operating conditions. Thruster efficiencies of about 0.5 appear practical for the 1000 to 2000 s range of specific impulse. Lifetime information is limited, but values of several thousands of hours should be possible with anode layer thrusters operated or = to 2000 s.

Sediment Characteristics and Transport in the Kootenai River White Sturgeon Critical Habitat near Bonners Ferry, Idaho

USGS Publications Warehouse

Fosness, Ryan L.; Williams, Marshall L.

2009-01-01

Recovery efforts for the endangered Kootenai River population of white sturgeon require an understanding of the characteristics and transport of suspended and bedload sediment in the critical habitat reach of the river. In 2007 and 2008, the U.S. Geological Survey in cooperation with the Kootenai Tribe of Idaho, conducted suspended- and bedload-sediment sampling in the federally designated critical habitat of the endangered Kootenai River white sturgeon population. Three sediment-sampling sites were selected that represent the hydraulic differences in the critical habitat. Suspended- and bedload-sediment samples along with acoustic Doppler current profiles were collected at these sites during specific river discharges. Samples were analyzed to determine suspended- and bedload-sediment characteristics and transport rates. Sediment transport data were analyzed to provide total loading estimates for suspended and bedload sediment in the critical habitat reach. Total suspended-sediment discharge primarily occurred as fine material that moved through the system in suspension. Total suspended-sediment discharge ranged from about 300 metric tons per day to more than 23,000 metric tons per day. Total suspended sediment remained nearly equal throughout the critical habitat, with the exception of a few cases where mass wasting of the banks may have caused sporadic spikes in total suspended sediment. Bedload-sediment discharge averaged 0-3 percent of the total loading. These bedload discharges ranged from 0 to 271 tons per day. The bedload discharge in the upper part of the critical habitat primarily consisted of fine to coarse gravel. A decrease in river competence in addition to an armored channel may be the cause of this limited bedload discharge. The bedload discharge in the middle part of the white sturgeon critical habitat varied greatly, depending on the extent of the backwater from Kootenay Lake. A large quantity of fine-to-coarse gravel is present in the braided reach, but the duration of transport for these gravels is limited by the encroaching backwater of Kootenay Lake. Bedload discharge in the lower part of the white sturgeon critical habitat primarily consisted of fine to coarse sand due to decreased velocities as a result of the backwater from Kootenay Lake.

Fifteen cm mercury ion thruster research, 1976. [performance as effected by the use of shag optics at 33 v discharge voltage

NASA Technical Reports Server (NTRS)

Wilbur, P. J.

1976-01-01

Improvements in 15 cm diameter, SERT II, mercury ion thruster performance effected by the use of SHAG optics at 33 V discharge voltage were discussed. At a 200 eV/ion discharge power, 90 percent propellant utilization and 660 mA beam current condition a doubly-to-singly charged ion current ratio of about 4 percent was measured. Performance of the 15 cm multipole mercury thruster (optimized for length and the point of electron injection) was compared to that of divergent (SERT II) and cusped field designs and found to be comparable. The need for a magnetic baffle in the multipole thruster was identified and the preferred point of electron injection was at the upstream end of the discharge chamber. Results of preliminary tests on the effects of discharge voltage and total accelerating voltage on perveance and beam divergence characteristics of two grid ion optics were examined. Experimental data showing the effect of target temperature on sputtering rates in a mercury discharge environment were presented and a deficiency in the tests procedure was identified.

Overview of the Helicity Injected Torus (HIT) Program

NASA Astrophysics Data System (ADS)

Redd, A. J.; Jarboe, T. R.; Hamp, W. T.; Nelson, B. A.; O'Neill, R. G.; Sieck, P. E.; Smith, R. J.; Sutphin, G. L.; Wrobel, J. S.

2007-06-01

The Helicity Injected Torus with Steady Inductive Helicity Injection (HIT-SI) consists of a "bowtie"-shaped axisymmetric confinement region, with two half-torus helicity injectors mounted on each side of the axisymmetric flux conserver [Sieck et al, IEEE Trans. Plasma Sci., v.33, p.723 (2005); Jarboe, Fusion Technology, v.36, p.85 (1999)]. Current and flux are driven sinusoidally with time in each injector, with the goal of generating and sustaining an axisymmetric spheromak in the main confinement region. Improvements in machine conditioning have enabled systematic study of HIT-SI discharges with significant toroidal current ITOR, including cases in which this current ITOR switches sign one or more times during the discharge. Statistical studies of all HIT-SI discharges to date demonstrate a minimum injected power to form significant ITOR, and that the maximum ITOR scales approximately linearly with the total injected power.

Electrostatic Discharge Properties of Irradiated Nanocomposites

DTIC Science & Technology

2009-03-01

47 24. Example Plot of Mean Current vs . Voltage Difference Curves ..................................48 25...across dielectric surfaces and prevent ESD arcing to very high voltage differentials (Figure 2) [7]. All of these drastic alterations in material...structure currents (3) Area thickness and dielectric strength of the material (4) Total charge involved in the event (5) Breakdown voltage (6) Current

River Discharge and Bathymetry Estimation from Hydraulic Inversion of Surface Currents and Water Surface Elevation Observations

NASA Astrophysics Data System (ADS)

Simeonov, J.; Holland, K. T.

2015-12-01

We developed an inversion model for river bathymetry and discharge estimation based on measurements of surface currents, water surface elevation and shoreline coordinates. The model uses a simplification of the 2D depth-averaged steady shallow water equations based on a streamline following system of coordinates and assumes spatially uniform bed friction coefficient and eddy viscosity. The spatial resolution of the predicted bathymetry is related to the resolution of the surface currents measurements. The discharge is determined by minimizing the difference between the predicted and the measured streamwise variation of the total head. The inversion model was tested using in situ and remote sensing measurements of the Kootenai River east of Bonners Ferry, ID. The measurements were obtained in August 2010 when the discharge was about 223 m3/s and the maximum river depth was about 6.5 m. Surface currents covering a 10 km reach with 8 m spatial resolution were estimated from airborne infrared video and were converted to depth-averaged currents using acoustic Doppler current profiler (ADCP) measurements along eight cross-stream transects. The streamwise profile of the water surface elevation was measured using real-time kinematic GPS from a drifting platform. The value of the friction coefficient was obtained from forward calibration simulations that minimized the difference between the predicted and measured velocity and water level along the river thalweg. The predicted along/cross-channel water depth variation was compared to the depth measured with a multibeam echo sounder. The rms error between the measured and predicted depth along the thalweg was found to be about 60cm and the estimated discharge was 5% smaller than the discharge measured by the ADCP.

Dynamics of current sheath in a hollow electrode Z-pinch discharge using slug model

NASA Astrophysics Data System (ADS)

Abd Al-Halim, Mohamed A.; Afify, M. S.

2017-03-01

The hollow electrode Z-pinch (HEZP) experiment is a new construction for the electromagnetic propulsion application in which the plasma is formed by the discharge between a plate and ring electrodes through which the plasma is propelled. The experimental results for 8 kV charging voltage shows that the peak discharge current is about 109 kA, which is in good agreement with the value obtained from the simulation in the slug model that simulates the sheath dynamics in the HEZP. The fitting of the discharge current from the slug model indicates that the total system inductance is 238 nH which is relatively a high static inductance accompanied with a deeper pinch depth indicating that the fitted anomalous resistance would be about 95 mΩ. The current and mass factors vary with the changing the gas pressure and the charging voltage. The current factor is between 0.4 and 0.5 on average which is relatively low value. The mass factor decreases by increasing the gas pressure indicating that the sheath is heavy to be driven by the magnetic pressure, which is also indicated from the decreases of the drive factor, hence the radial sheath velocity decreases. The plasma inductance and temperature increase with the increase of the drive factor while the minimum pinch radius decreases.

Increased freshwater discharge shifts the trophic balance in the coastal zone of the northern Baltic Sea

PubMed Central

Wikner, Johan; Andersson, Agneta

2012-01-01

Increased precipitation is one projected outcome of climate change that may enhance the discharge of freshwater to the coastal zone. The resulting lower salinity, and associated discharge of both nutrients and dissolved organic carbon, may influence food web functioning. The scope of this study was to determine the net outcome of increased freshwater discharge on the balance between auto- and heterotrophic processes in the coastal zone. By using long-term ecological time series data covering 13 years, we show that increased river discharge suppresses phytoplankton biomass production and shifts the carbon flow towards microbial heterotrophy. A 76% increase in freshwater discharge resulted in a 2.2 times higher ratio of bacterio- to phytoplankton production (Pb:Pp). The level of Pb:Pp is a function of riverine total organic carbon supply to the coastal zone. This is mainly due to the negative effect of freshwater and total organic carbon discharge on phytoplankton growth, despite a concomitant increase in discharge of nitrogen and phosphorus. With a time lag of 2 years the bacterial production recovered after an initial decline, further synergistically elevating the microbial heterotrophy. Current climate change projections suggesting increased precipitation may therefore lead to increased microbial heterotrophy, thereby decreasing the transfer efficiency of biomass to higher trophic levels. This prognosis would suggest reduced fish production and lower sedimentation rates of phytoplankton, a factor of detriment to benthic fauna. Our findings show that discharge of freshwater and total organic carbon significantly contributes to the balance of coastal processes at large spatial and temporal scales, and that model's would be greatly augmented by the inclusion of these environmental drivers as regulators of coastal productivity.

Feasibility of a nickel-metal hydride battery for totally implantable artificial hearts.

PubMed

Okamoto, E; Yoshida, T; Fujiyoshi, M; Shimanaka, M; Takeuchi, A; Mitamura, Y; Mikami, T

1996-01-01

An implantable rechargeable battery is one of the key technologies for totally implantable artificial hearts. The nickel-metal hydride (Ni-MH) battery is promising for its high energy density of 1.5-2.0 times that of a nickel-cadmium battery. In this study, the effects of pulsatile discharge loads on the operating time and cycle life of Ni-MH batteries at 39 degrees C were studied. Two battery cells (TH-3M, 1,200 mAh, phi 14.5 x 49 mm; Toshiba, Tokyo, Japan) in series were charge/discharge cycled at 39 degrees C using a charge current of 1CA (1,200 mA) and then were fully discharged to 1.0 V/cell under either pulsatile discharge loads, which mimicked a systole (1 A for 0.3 sec) and a diastole (0.4 A for 0.3 sec), or a non pulsatile discharge load equivalent to the average of the pulsatile loads (0.7 A). Each cycle life test was interrupted on the 482nd cycle under pulsatile load, and on the 423rd cycle under non pulsatile load, because of malfunction of each battery charger. The tests showed that the pulsatile discharge cells had significantly (p < 0.001) less operating time (74.0 +/- 7.15 min) throughout the test period (up to 482 days) compared to the cells under equivalent non pulsatile discharge loads (93.7 +/- 7.74 min). The pulsatile-discharged Ni-MH cells provide significantly less operating time than the constantly discharged cells; the Ni-MH battery has an operating time of over 78 min and a cycle life of almost 500 cycles at 39 degrees C. In conclusion, the Ni-MH battery is feasible as an implantable back-up battery for a totally implantable artificial heart system.

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.

Modelling the dispersion of treated wastewater in a shallow coastal wind-driven environment, Geographe Bay, Western Australia: implications for environmental management.

PubMed

Dunn, Ryan J K; Zigic, Sasha; Shiell, Glenn R

2014-10-01

Numerical models are useful for predicting the transport and fate of contaminants in dynamic marine environments, and are increasingly a practical solution to environmental impact assessments. In this study, a three-dimensional hydrodynamic model and field data were used to validate a far-field dispersion model that, in turn, was used to determine the fate of treated wastewater (TWW) discharged to the ocean via a submarine ocean outfall under hypothetical TWW flows. The models were validated with respect to bottom and surface water current speed and direction, and in situ measurements of total nitrogen and faecal coliforms. Variations in surface and bottom currents were accurately predicted by the model as were nutrient and coliform concentrations. Results indicated that the ocean circulation was predominately wind driven, evidenced by relatively small oscillations in the current speeds along the time-scale of the tide, and that dilution mixing zones were orientated in a predominantly north-eastern direction from the outfall and parallel to the coastline. Outputs of the model were used to determine the 'footprint' of the TWW plume under a differing discharge scenario and, particularly, whether the resultant changes in TWW contaminants, total nitrogen and faecal coliforms would meet local environmental quality objectives (EQO) for ecosystem integrity, shellfish harvesting and primary recreation. Modelling provided a practical solution for predicting the dilution of contaminants under a hypothetical discharge scenario and a means for determining the aerial extent of exclusion zones, where the EQOs for shellfish harvesting and primary recreation may not always be met. Results of this study add to the understanding of regional discharge conditions and provide a practical case study for managing impacts to marine environments under a differing TWW discharge scenario, in comparison to an existing scenario.

Quantifying the Journey of a Turbidity Current: How Water and Sediment Discharges Vary with Distance in Monterey Canyon

NASA Astrophysics Data System (ADS)

Chapplow, N.; Talling, P.; Cartigny, M.; Parsons, D. R.; Simmons, S.; Clare, M. A.; Paull, C. K.

2017-12-01

Turbidity currents transport vast quantities of sediment across the seafloor and form the largest sediment accumulations on Earth. Such flows pose a hazard to strategically important seafloor infrastructure and are important agents for the transport of organic carbon and nutrients that support deep-sea ecosystems. It is therefore important to quantify the scale of these flows, how much sediment they transport, and how their discharge evolves over time and space along their flow path. Two modes of flow evolution have been proposed based on experimental and numerical models. The first is termed ignition, where flows entrain seafloor sediment and become more voluminous and powerful and increase in discharge. The second is dissipation, where sediment falls out of suspension, flows decelerate and lose discharge. Field-scale turbidity currents have only been measured at a handful of sites worldwide, however, and never at multiple locations along their full course. Therefore, it has not been possible to determine when, where and why flows diverge into these two modes in the deep sea and how discharge of the flows varies. The ambitious multi-institution Coordinated Canyon Experiment measured turbidity currents at seven instrumented moorings along the Monterey Canyon, offshore California. Fifteen flows were recorded, including the fastest events yet measured at high resolution (>8 m/s). This remarkable dataset provides the first opportunity to quantify down-channel sediment and flow discharge evolution of turbidity currents in the deep sea. To understand whether flows ignite or dissipate, we derive total and sediment discharges for each of the flows at all seven mooring locations down the canyon. Discharges are calculated from measured velocities, and sediment concentrations derived using a novel inversion method. Two distinct flow modes are observed, where most flows rapidly dissipated in the upper reaches of the canyon, while three ran out for the full 50 km array length. We then explore why only these three flows ignited and discuss the implications for canyon and channel capacity and evolution.

Hyperpycnal sediment discharge from semiarid southern California rivers: Implications for coastal sediment budgets

USGS Publications Warehouse

Warrick, J.A.; Milliman, John D.

2003-01-01

Southern California rivers discharge hyperpycnal (river density greater than ocean density) concentrations of suspended sediment (>40 g/L, according to buoyancy theory) during flood events, mostly during El Nin??o-Southern Oscillation (ENSO) conditions. Because hyperpycnal river discharge commonly occurs during brief periods (hours to occasionally days), mean daily flow statistics often do not reveal the magnitude of these events. Hyperpycnal events are particularly important in rivers draining the Transverse Range and account for 75% of the cumulative sediment load discharged by the Santa Clara River over the past 50 yr. These events are highly pulsed, totaling only ??? 30 days (??? 0.15% of the total 50 yr period). Observations of the fate of sediment discharge, although rare, are consistent with hyperpycnal river dynamics and the high likelihood of turbidity currents during these events. We suggest that much of the sediment load initially bypasses the littoral circulation cells and is directly deposited on the adjacent continental shelf, thus potentially representing a loss of immediate beach sand supply. During particularly exceptional events (>100 yr recurrence intervals), flood underflows may extend past the shelf and escape to offshore basins.

A power-balance model for local helicity injection startup in a spherical tokamak

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

Barr, Jayson L.; Bongard, Michael W.; Burke, Marcus G.

A 0D circuit model for predicting I p( t) in Local Helicity Injection (LHI) discharges is developed. Analytic formulas for estimating the surface flux of finite-A plasmas developed are modified and expanded to treat highly shaped, ultralow-A tokamak geometry using a database of representative equilibria. Model predictions are compared to sample LHI discharges in the A ~ 1 Pegasus spherical tokamak, and are found to agree within 15% of experimental I p( t). High performance LHI discharges are found to follow the Taylor relaxation current limit for approximately the first half of the current ramp, or I p ≲ 75more » kA. The second half of the current ramp follows a limit imposed by power-balance as plasmas expand from high- A to ultralow- A. Here, this shape evolution generates a significant drop in external plasma inductance, effectively using the plasma’s initially high inductance to drive the current ramp and provide > 70% of the current drive V-s. Projections using this model indicate the relative influences of higher helicity input rate and injector current on the attainable total plasma current.« less

A power-balance model for local helicity injection startup in a spherical tokamak

DOE PAGES

Barr, Jayson L.; Bongard, Michael W.; Burke, Marcus G.; ...

2018-05-15

A 0D circuit model for predicting I p( t) in Local Helicity Injection (LHI) discharges is developed. Analytic formulas for estimating the surface flux of finite-A plasmas developed are modified and expanded to treat highly shaped, ultralow-A tokamak geometry using a database of representative equilibria. Model predictions are compared to sample LHI discharges in the A ~ 1 Pegasus spherical tokamak, and are found to agree within 15% of experimental I p( t). High performance LHI discharges are found to follow the Taylor relaxation current limit for approximately the first half of the current ramp, or I p ≲ 75more » kA. The second half of the current ramp follows a limit imposed by power-balance as plasmas expand from high- A to ultralow- A. Here, this shape evolution generates a significant drop in external plasma inductance, effectively using the plasma’s initially high inductance to drive the current ramp and provide > 70% of the current drive V-s. Projections using this model indicate the relative influences of higher helicity input rate and injector current on the attainable total plasma current.« less

Quantifying acoustic doppler current profiler discharge uncertainty: A Monte Carlo based tool for moving-boat measurements

USGS Publications Warehouse

Mueller, David S.

2017-01-01

This paper presents a method using Monte Carlo simulations for assessing uncertainty of moving-boat acoustic Doppler current profiler (ADCP) discharge measurements using a software tool known as QUant, which was developed for this purpose. Analysis was performed on 10 data sets from four Water Survey of Canada gauging stations in order to evaluate the relative contribution of a range of error sources to the total estimated uncertainty. The factors that differed among data sets included the fraction of unmeasured discharge relative to the total discharge, flow nonuniformity, and operator decisions about instrument programming and measurement cross section. As anticipated, it was found that the estimated uncertainty is dominated by uncertainty of the discharge in the unmeasured areas, highlighting the importance of appropriate selection of the site, the instrument, and the user inputs required to estimate the unmeasured discharge. The main contributor to uncertainty was invalid data, but spatial inhomogeneity in water velocity and bottom-track velocity also contributed, as did variation in the edge velocity, uncertainty in the edge distances, edge coefficients, and the top and bottom extrapolation methods. To a lesser extent, spatial inhomogeneity in the bottom depth also contributed to the total uncertainty, as did uncertainty in the ADCP draft at shallow sites. The estimated uncertainties from QUant can be used to assess the adequacy of standard operating procedures. They also provide quantitative feedback to the ADCP operators about the quality of their measurements, indicating which parameters are contributing most to uncertainty, and perhaps even highlighting ways in which uncertainty can be reduced. Additionally, QUant can be used to account for self-dependent error sources such as heading errors, which are a function of heading. The results demonstrate the importance of a Monte Carlo method tool such as QUant for quantifying random and bias errors when evaluating the uncertainty of moving-boat ADCP measurements.

Vibrational kinetics in CO electric discharge lasers - Modeling and experiments

NASA Technical Reports Server (NTRS)

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

1980-01-01

A model of CO laser vibrational kinetics is developed, and predicted vibrational distributions are compared with measurements. The experimental distributions were obtained at various flow locations in a transverse CW discharge in supersonic (M = 3) flow. Good qualitative agreement is obtained in the comparisons, including the prediction of a total inversion at low discharge current densities. The major area of discrepancy is an observed loss in vibrational energy downstream of the discharge which is not predicted by the model. This discrepancy may be due to three-dimensional effects in the experiment which are not included in the model. Possible kinetic effects which may contribute to vibrational energy loss are also examined.

The effect of working gas pressure on the switching rate of a kivotron

NASA Astrophysics Data System (ADS)

Bokhan, P. A.; Gugin, P. P.; Zakrevsky, D. E.; Lavrukhin, M. A.

2016-05-01

The switching rate in gas-discharge devices (kivotrons) based on an "open" discharge with counterpropagating electron beams is studied experimentally. Structures with a total cathode area of 2 cm2 were used. A monotonic reduction in the switching time with an increase in the working gas pressure and in the voltage amplitude at the time of breakdown is demonstrated. The minimum switching time is ~240 ps at a voltage of 17 kV. The maximum current rise rate, which is limited by the discharge circuit inductance, is 3 × 1012 A/s.

Combined corona discharge and UV photoionization source for ion mobility spectrometry.

PubMed

Bahrami, Hamed; Tabrizchi, Mahmoud

2012-08-15

An ion mobility spectrometer is described which is equipped with two non-radioactive ion sources, namely an atmospheric pressure photoionization and a corona discharge ionization source. The two sources cannot only run individually but are additionally capable of operating simultaneously. For photoionization, a UV lamp was mounted parallel to the axis of the ion mobility cell. The corona discharge electrode was mounted perpendicular to the UV radiation. The total ion current from the photoionization source was verified as a function of lamp current, sample flow rate, and drift field. Simultaneous operation of the two ionization sources was investigated by recording ion mobility spectra of selected samples. The design allows one to observe peaks from either the corona discharge or photoionization individually or simultaneously. This makes it possible to accurately compare peaks in the ion mobility spectra from each individual source. Finally, the instrument's capability for discriminating two peaks appearing in approximately identical drift times using each individual ionization source is demonstrated. Copyright © 2012 Elsevier B.V. All rights reserved.

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.

Experimental study of electrical discharge drilling of stainless steel UNS S30400

NASA Astrophysics Data System (ADS)

Hanash, E. A. H.; Ali, M. Y.

2018-01-01

In this study, overcut and taper angle were investigated in machining of stainless steel UNS S30400 against three different electrical discharge machining parameters which are electric current (Ip), pulse on-time (Ton) and pulse off-time (Toff). The electrode used was of 1 mm diameter with aspect ratio of 10. Dimensional accuracy was measured by evaluating overcut and taper angle. Those two measurements were performed using optical microscope model (Olympus BX41M, Japan). The experimentation planning, evaluation, analysis and optimization have been carried out using DOE software version 10.0.3 RSM based method with total number of twenty experiments. The research reveals that, discharge current was found to have the most significant effect on overcut and taper angle followed by pulse on-time and pulse off-time. As the discharge current and pulse on-time increase, overcut and taper angle are increased. However, when pulse off-time increases, overcut and taper angle decrease. The outcome result of this study will be very useful in the manufacturing industry to select the appropriate parameters for the selected work material. The model has shown a great accuracy with percentage error of less than 5%.

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

Forecasting Daily Patient Outflow From a Ward Having No Real-Time Clinical Data

PubMed Central

Tran, Truyen; Luo, Wei; Phung, Dinh; Venkatesh, Svetha

2016-01-01

Background: Modeling patient flow is crucial in understanding resource demand and prioritization. We study patient outflow from an open ward in an Australian hospital, where currently bed allocation is carried out by a manager relying on past experiences and looking at demand. Automatic methods that provide a reasonable estimate of total next-day discharges can aid in efficient bed management. The challenges in building such methods lie in dealing with large amounts of discharge noise introduced by the nonlinear nature of hospital procedures, and the nonavailability of real-time clinical information in wards. Objective Our study investigates different models to forecast the total number of next-day discharges from an open ward having no real-time clinical data. Methods We compared 5 popular regression algorithms to model total next-day discharges: (1) autoregressive integrated moving average (ARIMA), (2) the autoregressive moving average with exogenous variables (ARMAX), (3) k-nearest neighbor regression, (4) random forest regression, and (5) support vector regression. Although the autoregressive integrated moving average model relied on past 3-month discharges, nearest neighbor forecasting used median of similar discharges in the past in estimating next-day discharge. In addition, the ARMAX model used the day of the week and number of patients currently in ward as exogenous variables. For the random forest and support vector regression models, we designed a predictor set of 20 patient features and 88 ward-level features. Results Our data consisted of 12,141 patient visits over 1826 days. Forecasting quality was measured using mean forecast error, mean absolute error, symmetric mean absolute percentage error, and root mean square error. When compared with a moving average prediction model, all 5 models demonstrated superior performance with the random forests achieving 22.7% improvement in mean absolute error, for all days in the year 2014. Conclusions In the absence of clinical information, our study recommends using patient-level and ward-level data in predicting next-day discharges. Random forest and support vector regression models are able to use all available features from such data, resulting in superior performance over traditional autoregressive methods. An intelligent estimate of available beds in wards plays a crucial role in relieving access block in emergency departments. PMID:27444059

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

Krauz, V. I., E-mail: krauz@nfi.kiae.ru; Mitrofanov, K. N.; Voitenko, D. A.

Results are presented from magnetic probe measurements in the pinching region formed during the compression of the plasma current sheath (PCS) in a discharge in deuterium at the KPF-4-Phoenix plasma focus facility. The fine structure (shock front-magnetic piston) of the PCS and its time evolution in the course of plasma compression toward the facility axis was studied by means of magnetic probes. It is shown that the fraction of the current transported into the axial region by the PCS does not exceed 65% of the total discharge current. The integral neutron yield Y{sub n} is well described by the formulamore » Y{sub n} ≈ (1.5–3) × 10{sup 10}I{sub p}{sup 4}, where I{sub p} (in MA) is the pinch current flowing in the region r ≤ 22 mm.« less

Characterization and Performance of a High-Current-Density Ion Implanter with Magnetized Hollow-Cathode Plasma Source

NASA Astrophysics Data System (ADS)

Falkenstein, Zoran; Rej, Donald; Gavrilov, Nikolai

1998-10-01

In a collaboration between the Institute of Electrophysics (IEP) and the Los Alamos National Laboratory (LANL), the IEP has developed an industrial scalable, high-power, large-area ion source for the surface modification of materials. The plasma source of the ion beam source can be described as a pulsed glow discharge with a cold, hollow-cathode in a weak magnetic field. Extraction and focusing of positive ions by an acceleration and ion-optical plate system renders the generation of a homogeneous, large-area ion beam with an averaged total ion current of up to 50 mA at acceleration voltages of up to 50 kV. The principle set-up of the ion beam source as well as some electrical characteristics (gas discharge current and the extracted ion beam current) are presented for a lab-scale prototype. Measurements of the radial ion current density profiles within the ion beam for various discharge parameters, as well as results on surface modification by ion implantation of nitrogen into aluminum and chromium are presented. Finally, a comparison of the applied ion dose with the retained ion doses is given.

Probe Measurements of Parameters of Streamers of Nanosecond Frequency Crown Discharge

NASA Astrophysics Data System (ADS)

Ponizovskiy, A. Z.; Gosteev, S. G.

2017-12-01

Investigations of the parameters of single streamers of nanosecond frequency corona discharge, creating a voluminous low-temperature plasma in extended coaxial electrode systems, are performed. Measurements of the parameters of streamers were made by an isolated probe situated on the outer grounded electrode. Streamers were generated under the action of voltage pulses with a front of 50-300 ns, duration of 100-600 ns, and amplitude up to 100 kV at the frequency of 50-1000 Hz. The pulse voltage, the total current of the corona, current per probe, and glow in the discharge gap were recorded in the experiments. It was established that, at these parameters of pulse voltage, streamers propagate at an average strength of the electric field of 4-10 kV/cm. Increasing the pulse amplitude leads to an increase in the number of streamers hitting the probe, an increase in the average charge of the head of a streamer, and, as a consequence, an increase in the total streamer current and the energy introduced into the gas. In the intervals up to 3 cm, streamer breakdown at an average field strength of 5-10 kV/cm is possible. In longer intervals, during the buildup of voltage after generation of the main pulse, RF breakdown is observed at E av ≈ 4 kV/cm.

Simulation of ground-water flow and evaluation of water-management alternatives in the Assabet River Basin, Eastern Massachusetts

USGS Publications Warehouse

DeSimone, Leslie A.

2004-01-01

Water-supply withdrawals and wastewater disposal in the Assabet River Basin in eastern Massachusetts alter the flow and water quality in the basin. Wastewater discharges and stream-flow depletion from ground-water withdrawals adversely affect water quality in the Assabet River, especially during low-flow months (late summer) and in headwater areas. Streamflow depletion also contributes to loss of aquatic habitat in tributaries to the river. In 19972001, water-supply withdrawals averaged 9.9 million gallons per day (Mgal/d). Wastewater discharges to the Assabet River averaged 11 Mgal/d and included about 5.4 Mgal/d that originated from sources outside of the basin. The effects of current (2004) and future withdrawals and discharges on water resources in the basin were investigated in this study. Steady-state and transient ground-water-flow models were developed, by using MODFLOW-2000, to simulate flow in the surficial glacial deposits and underlying crystalline bedrock in the basin. The transient model simulated the average annual cycle at dynamic equilibrium in monthly intervals. The models were calibrated to 19972001 conditions of water withdrawals, wastewater discharges, water levels, and nonstorm streamflow (base flow plus wastewater discharges). Total flow through the simulated hydrologic system averaged 195 Mgal/d annually. Recharge from precipitation and ground-water discharge to streams were the dominant inflow and outflow, respectively. Evapotranspiration of ground water from wetlands and non-wetland areas also were important losses from the hydrologic system. Water-supply withdrawals and infiltration to sewers averaged 5 and 1.3 percent, respectively, of total annual out-flows and were larger components (12 percent in September) of the hydrologic system during low-flow months. Water budgets for individual tributary and main stem subbasins identified areas, such as the Fort Meadow Brook and the Assabet Main Stem Upper subbasins, where flows resulting from anthropo-genic activities were relatively large percentages, compared to other subbasins, (more than 20 percent in September) of total out-flows. Wastewater flows in the Assabet River accounted for 55, 32, and 20 percent of total nonstorm streamflow (base flow plus wastewater discharge) out of the Assabet Main Stem Upper, Middle, and Lower subbasins, respectively, in an average September. The ground-water-flow models were used to evaluate water-management alternatives by simulating hypothetical scenarios of altered withdrawals and discharges. A scenario that included no water management quantified nonstorm stream-flows that would result without withdrawals, discharges, septic-system return flow, or consumptive use. Tributary flows in this scenario increased in most subbasins by 2 to 44 percent relative to 19972001 conditions. The increases resulted mostly from variable combinations of decreased withdrawals and decreased infiltration to sewers. Average annual nonstorm streamflow in the Assabet River decreased slightly in this scenario, by 2 to 3 percent annually, because gains in ground-water discharge were offset by the elimination of wastewater discharges. A second scenario quantified the effects of increasing withdrawals and discharges to currently permitted levels. In this simulation, average annual tributary flows decreased in most subbasins, by less than 1 to 10 percent relative to 19972001 conditions. In the Assabet River, flows increased slightly, 1 to 5 percent annually, and the percentage of wastewater in the river increased to 69, 42, and 27 percent of total nonstorm streamflow out of the Assabet Main Stem Upper, Middle, and Lower subbasins, respectively, in an average September. A third set of scenarios quantified the effects of ground-water discharge of wastewater at four hypothetical sites, while maintaining 19972000 wastewater discharges to the Assabet River. Wastewater, discharged at a constant rate that varied among sites from 0.3 to 1

An advanced negative hydrogen ion source

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

Goncharov, Alexey A., E-mail: gonchar@iop.kiev.ua; Dobrovolsky, Andrey N.; Goretskii, Victor P.

2016-02-15

The results of investigation of emission productivity of negative particles source with cesiated combined discharge are presented. A cylindrical beam of negative hydrogen ions with density about 2 A/cm{sup 2} in low noise mode on source emission aperture is obtained. The total beam current values are up to 200 mA for negative hydrogen ions and up to 1.5 A for all negative particles with high divergence after source. The source has simple design and can produce stable discharge with low level of oscillation.

Acceleration processes in the quasi-steady magnetoplasmadynamic discharge. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Boyle, M. J.

1974-01-01

The flow field characteristics within the discharge chamber and exhaust of a quasi-steady magnetoplasmadynamic (MPD) arcjet were examined to clarify the nature of the plasma acceleration process. The observation of discharge characteristics unperturbed by insulator ablation and terminal voltage fluctuations, first requires the satisfaction of three criteria: the use of refractory insulator materials; a mass injection geometry tailored to provide propellant to both electrode regions of the discharge; and a cathode of sufficient surface area to permit nominal MPD arcjet operation for given combinations of arc current and total mass flow. The axial velocity profile and electromagnetic discharge structure were measured for an arcjet configuration which functions nominally at 15.3 kA and 6 g/sec argon mass flow. An empirical two-flow plasma acceleration model is advanced which delineates inner and outer flow regions and accounts for the observed velocity profile and calculated thrust of the accelerator.

Low-Power Operation and Plasma Characterization of a Qualification Model SPT-140 Hall Thruster for NASA Science Missions

NASA Technical Reports Server (NTRS)

Garner, Charles E.; Jorns, Benjamin A.; van Derventer, Steven; Hofer, Richard R.; Rickard, Ryan; Liang, Raymond; Delgado, Jorge

2015-01-01

Hall thruster systems based on commercial product lines can potentially lead to lower cost electric propulsion (EP) systems for deep space science missions. A 4.5-kW SPT-140 Hall thruster presently under qualification testing by SSL leverages the substantial heritage of the SPT-100 being flown on Russian and US commercial satellites. The Jet Propulsion Laboratory is exploring the use of commercial EP systems, including the SPT-140, for deep space science missions, and initiated a program to evaluate the SPT-140 in the areas of low power operation and thruster operating life. A qualification model SPT-140 designated QM002 was evaluated for operation and plasma properties along channel centerline, from 4.5 kW to 0.8 kW. Additional testing was performed on a development model SPT-140 designated DM4 to evaluate operation with a Moog proportional flow control valve (PFCV). The PFCV was commanded by an SSL engineering model PPU-140 Power Processing Unit (PPU). Performance measurements on QM002 at 0.8 kW discharge power were 50 mN of thrust at a total specific impulse of 1250 s, a total thruster efficiency of 0.38, and discharge current oscillations of under 3% of the mean current. Steady-state operation at 0.8 kW was demonstrated during a 27 h firing. The SPT-140 DM4 was operated in closed-loop control of the discharge current with the PFCV and PPU over discharge power levels of 0.8-4.5 kW. QM002 and DM4 test data indicate that the SPT-140 design is a viable candidate for NASA missions requiring power throttling down to low thruster input power.

Development Status of a Power Processing Unit for Low Power Ion Thrusters

NASA Technical Reports Server (NTRS)

Pinero, Luis R.; Bowers, Glen E.; Lafontaine, Eric M.

2000-01-01

An advanced breadboard Power Processing Unit (PPU) for a low power ion propulsion system incorporating mass reduction techniques was designed and fabricated. As a result of similar output current requirements, the discharge supply was also used to provide the neutralizer heater and discharge heater functions by using three relays to switch the output connections. This multi-function supply reduces to four the number of power converters needed to produce the required six electrical outputs. Switching frequencies of 20 and 50 kHz were chosen as a compromise between the size of the magnetic components and switching losses. The advanced breadboard PPU is capable of a maximum total output power of 0.47 kW. Its component mass is 0.65 kg and its total mass 1.9 kg. The total efficiency at full power is 0.89.

The Spatial Expansion of a Discharge in the Generation and the Channel Structure (in German)

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

Schlumbohm, H.

1962-02-01

The spatial expansion of a discharge was investigated under homogeneous field conditions, using an anode with a small central area separated from the remainder and wide band double beam oscillographic techniques. The discharge currents were initiated by electrons released along traces of single alpha particles in the gas between the electrodes. The k particles enter the gap volume through a small hole in the middle of the separated center of the anode. The measurements have shown that a secondary photon emission from the cathode causes a spreading over the total gap volume within the first few electron generations (N 2,more » air, and CO 2 at lower pressures). If a streamer mechanism occurs (O 2 and CO 2 at higher pressures), the discharge remains localized to the trace of the alpha particle, in which the avalanches yielded by the primary electrons have produced a high density of positive ions. New details of steamer mechanism are revealed by analyzing the rapid increase of the current during streamer formation.« less

34 CFR 685.213 - Total and permanent disability discharge.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 3 2010-07-01 2010-07-01 false Total and permanent disability discharge. 685.213... § 685.213 Total and permanent disability discharge. (a) General. (1) A borrower's Direct Loan is... on a total and permanent disability, a borrower must submit a discharge application to the Secretary...

Are Soft Short Tests Good Indicators of Internal Li-ion Cell Defects?

NASA Technical Reports Server (NTRS)

Jeevarajan, J.; Chung, J.-S.; Jung, K.; Park, J.

2013-01-01

The self discharge test at full state of charge, may not be a good one to detect subtle defects since the li-ion chemistry has the highest self discharge at full state of charge. One should characterize self discharge versus storage time for each cell manufacturer/design to differentiate between normal self discharge and that due to a subtle manufacturing defect. The various soft short test methods indicate that if this test is carried out at full discharge (0% SOC) with all capacity removed (by lowering the current load in a stepwise manner to the same end of discharge voltage), then the cells need to be placed in storage for more than 72 hours to get a good analysis on the presence of subtle defects since it takes more than 72 hours to achieve voltage stabilization. If the cells are to be charged up even to a small percentage (ex. 1%), 72 hours are sufficient to determine issues. However, the pass/fail criteria should be based on a valid OCV decline. Less than 10 mV voltage decline is not a good method to detect subtle defects. As mentioned in the first bullet, self discharge is a competing reaction when a charge is introduced and hence a characterization of the self discharge versus storage time is required to fully correlate voltage decline to a failure due to a subtle defect. Soft short test method cannot be relied on for defect detection because cells with and without voltage decline seemed to have similar defects and characteristics. Screening methods such as internal resistance and capacity as well as a 3-sigma range for OCV, mass and dimensions should be used to screen out outliers. A very critical aspect in the understanding of subtle defects is to carry out destructive analysis of cells from every lot to confirm the quality of production and screen all cells and batteries in a stringent manner to have a high quality set of flight cells. Self Discharge Test: Fully charged cells shall be placed in Open circuit stand for 72 hours (OCV measurement twice a day); continue for total of 14 days with 1 reading per day 2. Soft Short Test 1: Fully charge; cells discharged to manufacturer's end of disch. Voltage (EODV) cutoff at C/5 rate; stand for 30 minutes; discharge with C/500 to the same EODV. stand for another 30 minutes; discharge the cells again using C/1000 current to the same EODV. OCV measurements twice a day for 72 hours and then for total of 14 days (data collection same as in 1.) 3. Soft Short Test 2: Fully charge; cells discharged to the manuf. EODV with a C/13 constant current; provide a 10 hour rest, discharge again to the same EODV with a current of C/250, provide a 10 hour rest, discharge again using a C/250 rate, provide a 24 hour rest, charge using C/250 to 3.15 V (for 12 hours). OCV measurements twice a day for at 72 hours. (data collection same as in 1.) 4. Soft Short Test 3: Fully charge; cells shall be discharged using C/10 current to manuf. EODV. Allow the cell to remain at Open circuit for 10 seconds. Discharge the cell at C/20 rate to the same EODV, hold open circuit for 24 hours. Discharge the cells at C/200 rate to the same end of voltage cutoff and hold open circuit for 24 hours. Discharge the cells one more time at C/200 rate to the same EODV and hold open circuit for 36 hours. Charge at C/200 rate to 3.15 V and hold for 3 days. Record OCV during the open circuit stand periods every 12 hours and at the beginning and end of the 3 day hold (include the 12 hour OCV recording during this time also). Capacity Cycling: Cells with declining voltages - one cell from each manufacturer chosen for cycling Destructive Physical Analysis (DPA): Cells with and without decline chosen from each lot for DPA.

The Effects of Urbanization and Flood Control on Sediment Discharge of a Southern California River, Evidence of a Dilution Effect

NASA Astrophysics Data System (ADS)

Warrick, J. A.; Orzech, K. M.; Rubin, D. M.

2004-12-01

The southern California landscape has undergone dramatic urbanization and population growth during the past 60 years and currently supports almost 20 million inhabitants. During this time, rivers of the region have been altered with damming, channel straightening and hardening, and water transfer engineering. These changes have drastically altered water and sediment discharge from most of the region's drainage basins. Here we focus on changes in sediment discharge from the largest watershed of southern California, the Santa Ana River. Order-of-magnitude drops in the suspended sediment rating curves (the relationship between suspended sediment concentration and instantaneous river discharge) are observed between 1967 and 2001, long after the construction of a major flood control dam in 1941. These sediment concentration decreases do not, however, represent alteration of the total sediment flux from the basin (a common interpretation of sediment rating curves), but rather a dilution of suspended sediment by increases (approx. 4x) in stormwater discharge associated with urbanization. Increases in peak and total stormwater discharge are consistent with runoff patterns from urbanizing landscapes, supporting our hypothesis that the diluting water originated from stormwater runoff generated in urban areas both up- and downstream of dams. Our dilution hypothesis is further supported with water and sediment budgets, dilution calculations, and suspended and bed grain size information.

Reversing-counterpulse repetitive-pulse inductive storage circuit

DOEpatents

Honig, Emanuel M.

1987-01-01

A high-power reversing-counterpulse repetitive-pulse inductive storage and transfer circuit includes an opening switch, a main energy storage coil, a counterpulse capacitor and a small inductor. After counterpulsing the opening switch off, the counterpulse capacitor is recharged by the main energy storage coil before the load pulse is initiated. This gives the counterpulse capacitor sufficient energy for the next counterpulse operation, although the polarity of the capacitor's voltage must be reversed before that can occur. By using a current-zero switch as the counterpulse start switch, the capacitor is disconnected from the circuit (with a full charge) when the load pulse is initiated, preventing the capacitor from depleting its energy store by discharging through the load. After the load pulse is terminated by reclosing the main opening switch, the polarity of the counterpulse capacitor voltage is reversed by discharging the capacitor through a small inductor and interrupting the discharge current oscillation at zero current and peak reversed voltage. The circuit enables high-power, high-repetition-rate operation with reusable switches and features total control (pulse-to-pulse) over output pulse initiation, duration, repetition rate, and, to some extent, risetime.

Reversing-counterpulse repetitive-pulse inductive storage circuit

DOEpatents

Honig, E.M.

1984-06-05

A high power reversing-counterpulse repetitive-pulse inductive storage and transfer circuit includes an opening switch, a main energy storage coil, a counterpulse capacitor and a small inductor. After counterpulsing the opening switch off, the counterpulse capacitor is recharged by the main energy storage coil before the load pulse is initiated. This gives the counterpulse capacitor sufficient energy for the next counterpulse operation, although the polarity of the capacitor's voltage must be reversed before that can occur. By using a current-zero switch as the counterpulse start switch, the capacitor is disconnected from the circuit (with a full charge) when the load pulse is initiated, preventing the capacitor from depleting its energy store by discharging through the load. After the load pulse is terminated by reclosing the main opening switch, the polarity of the counterpulse capacitor voltage is reversed by discharging the capacitor through a small inductor and interrupting the discharge current oscillation at zero current and peak reversed voltage. The circuit enables high-power, high-repetition-rate operation with reusable switches and features total control (pulse-to-pulse) over output pulse initiation, duration, repetition rate, and, to some extent, risetime.

Measurements of sulfur compounds in CO 2 by diode laser atomic absorption spectrometry

NASA Astrophysics Data System (ADS)

Franzke, J.; Stancu, D. G.; Niemax, K.

2003-07-01

Two simple methods for the analysis of the total concentration of sulfur in CO 2 by diode laser atomic absorption spectrometry of excited, metastable sulfur atoms in a direct current discharge are presented. In the first method, the CO 2 sample gas is mixed with the plasma gas (Ar or He) while the second is based on reproducible measurements of the sulfur released from the walls in a helium discharge after being deposited as a result of operating the discharge in pure CO 2 sample gas. The detection limits obtained satisfy the requirements for the control of sulfur compounds in CO 2 used in the food and beverage industry.

Newer anesthesia and rehabilitation protocols enable outpatient hip replacement in selected patients.

PubMed

Berger, Richard A; Sanders, Sheila A; Thill, Elizabeth S; Sporer, Scott M; Della Valle, Craig

2009-06-01

Advancements in the surgical approach, anesthetic technique, and the initiation of rapid rehabilitation protocols have decreased the duration of hospitalization and subsequent length of recovery following elective total hip arthroplasty. We assessed the feasibility and safety of outpatient total hip arthroplasty in 150 consecutive patients. A comprehensive perioperative anesthesia and rehabilitation protocol including preoperative teaching, regional anesthesia, and preemptive oral analgesia and antiemetic therapy was implemented around a minimally invasive surgical technique. A rapid rehabilitation pathway was started immediately after surgery and patients had the option of being discharged to home the day of surgery if standard discharge criteria were met. All 150 patients were discharged to home the day of surgery, at which time 131 patients were able to walk without assistive devices. Thirty-eight patients required some additional intervention outside the pathway to resolve nausea, hypotension, or sedation prior to discharge. There were no readmissions for pain, nausea, or hypotension yet there was one readmission for fracture and nine emergency room evaluations in the three month perioperative period. This anesthetic and rehabilitation protocol allowed outpatient total hip arthroplasty to be routinely performed in these consecutive patients undergoing primary total hip arthroplasty. With current reimbursement approaches the modest savings to the hospital in length of stay may be outweighed by the additional costs of personnel, thereby making this outpatient system more expensive to implement. Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Comparative analysis of discharges into Lake Michigan, Phase I - Southern Lake Michigan.

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

Veil, J. A.; Elcock, D.; Gasper, J. R.

2008-06-30

BP Products North America Inc. (BP) owns and operates a petroleum refinery located on approximately 1,700 acres in Whiting, East Chicago, and Hammond, Indiana, near the southern tip of Lake Michigan. BP provided funding to Purdue University-Calumet Water Institute (Purdue) and Argonne National Laboratory (Argonne) to conduct studies related to wastewater treatment and discharges. Purdue and Argonne are working jointly to identify and characterize technologies that BP could use to meet the previous discharge permit limits for total suspended solids (TSS) and ammonia after refinery modernization. In addition to the technology characterization work, Argonne conducted a separate project task, whichmore » is the subject of this report. In Phase I of a two-part study, Argonne estimated the current levels of discharge to southern Lake Michigan from significant point and nonpoint sources in Illinois, Indiana, and portions of Michigan. The study does not consider all of the chemicals that are discharged. Rather, it is narrowly focused on a selected group of pollutants, referred to as the 'target pollutants'. These include: TSS, ammonia, total and hexavalent chromium, mercury, vanadium, and selenium. In Phase II of the study, Argonne will expand the analysis to cover the entire Lake Michigan drainage basin.« less

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.

Dynamic model based on voltage transfer curve for pattern formation in dielectric barrier glow discharge

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

Li, Ben; He, Feng; Ouyang, Jiting, E-mail: jtouyang@bit.edu.cn

2015-12-15

Simulation work is very important for understanding the formation of self-organized discharge patterns. Previous works have witnessed different models derived from other systems for simulation of discharge pattern, but most of these models are complicated and time-consuming. In this paper, we introduce a convenient phenomenological dynamic model based on the basic dynamic process of glow discharge and the voltage transfer curve (VTC) to study the dielectric barrier glow discharge (DBGD) pattern. VTC is an important characteristic of DBGD, which plots the change of wall voltage after a discharge as a function of the initial total gap voltage. In the modeling,more » the combined effect of the discharge conditions is included in VTC, and the activation-inhibition effect is expressed by a spatial interaction term. Besides, the model reduces the dimensionality of the system by just considering the integration effect of current flow. All these greatly facilitate the construction of this model. Numerical simulations turn out to be in good accordance with our previous fluid modeling and experimental result.« less

Feedback control of the lower hybrid power deposition profile on Tore Supra

NASA Astrophysics Data System (ADS)

Barana, O.; Mazon, D.; Laborde, L.; Turco, F.

2007-07-01

The Tore Supra facility is well suited to study ITER relevant topics such as the real-time control of plasma current and the sustaining of steady-state discharges. This work describes a tool that was recently developed and implemented on Tore Supra to control in real time, by means of the direct knowledge of the suprathermal electron local emission profile, the width of the lower hybrid power deposition profile. This quantity can be considered to some extent equivalent to the width of the plasma current density profile in case of fully non-inductive discharges. This system takes advantage of an accurate hard x-ray diagnostics, of an efficient lower hybrid additional heating and of a reliable real-time communication network. The successful experiments carried out to test the system employed, as actuators, the parallel refractive index n// and the total power PLH. The control of the suprathermal electron local emission profile through n// was also integrated with the feedback control of the total plasma current IP with PLH and of the loop voltage Vloop with the central solenoid flux. These results demonstrate that the system is robust, reliable and able to counterbalance destabilizing events. This tool can be effectively used in the future in fully non-inductive discharges to improve the MHD stability and to maintain internal transport barriers or lower hybrid enhanced performance modes. The real-time control of the lower hybrid power deposition profile could also be used in conjunction with the electron-cyclotron radiofrequency heating for synergy studies.

Autonomous Method and System for Minimizing the Magnitude of Plasma Discharge Current Oscillations in a Hall Effect Plasma Device

NASA Technical Reports Server (NTRS)

Hruby, Vladimir (Inventor); Demmons, Nathaniel (Inventor); Ehrbar, Eric (Inventor); Pote, Bruce (Inventor); Rosenblad, Nathan (Inventor)

2014-01-01

An autonomous method for minimizing the magnitude of plasma discharge current oscillations in a Hall effect plasma device includes iteratively measuring plasma discharge current oscillations of the plasma device and iteratively adjusting the magnet current delivered to the plasma device in response to measured plasma discharge current oscillations to reduce the magnitude of the plasma discharge current oscillations.

IV INTERNATIONAL CONFERENCE ON ATOM AND MOLECULAR PULSED LASERS (AMPL'99): Efficient long-pulse XeCl laser with a prepulse formed by an inductive energy storage device

NASA Astrophysics Data System (ADS)

Baksht, E. Kh; Panchenko, Aleksei N.; Tarasenko, Viktor F.

2000-06-01

An efficient electric-discharge XeCl laser is developed, which is pumped by a self-sustained discharge with a prepulse formed by a generator with an inductive energy storage device and a semiconductor current interrupter on a basis of semiconductor opening switch (SOS) diodes. An output energy up to 800 mJ, a pulse length up to 450 ns, and a total laser efficiency of 2.2% were attained by using spark UV preionisation.

Direct current H- source for the medicine accelerator (invited)

NASA Astrophysics Data System (ADS)

Belchenko, Yu.; Savkin, V.

2004-05-01

A compact cw hydrogen negative ion source having reliable operation and a simplified maintenance is developed at Budker Institute of Nuclear Physics for a tandem accelerator of boron capture neutron therapy installation. The source uses a Penning discharge with a hydrogen and cesium feed through the hollows in the cathodes. Discharge voltage is about 60-80 V, current 9 A, hydrogen pressure 4-5 Pa, magnetic field 0.05-0.1 T, and cesium seed <1 mg/h. Negative ions are mainly produced on the cesiated anode surface due to conversion of hydrogen atoms. An optimal anode temperature is 250-350 °C. Negative ion beam current is directly proportional to the discharge current and to the emission hole area. A triode system for the beam extraction and acceleration system is used. The flux of accompanying extracted electrons was decreased by filtering in the transverse magnetic field. This electron flux was intercepted to the special electrode, biased at 4 kV potential with respect to the anode. Source stable cw operation for several hour runs was multiply tested. A H- ion beam with current up to 8 mA, beam energy 23 keV was produced regularly. Negative ion current of heavy impurities had a value of about 3% of the total beam current. Beam normalized emittance is about 0.3 π mm mrad and emission current density -0.1 A/cm2. A built-in cathode heater provides the operation quick start.

Discharge current modes of high power impulse magnetron sputtering

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

Wu, Zhongzhen, E-mail: wuzz@pkusz.edu.cn; Xiao, Shu; Ma, Zhengyong

2015-09-15

Based on the production and disappearance of ions and electrons in the high power impulse magnetron sputtering plasma near the target, the expression of the discharge current is derived. Depending on the slope, six possible modes are deduced for the discharge current and the feasibility of each mode is discussed. The discharge parameters and target properties are simplified into the discharge voltage, sputtering yield, and ionization energy which mainly affect the discharge plasma. The relationship between these factors and the discharge current modes is also investigated.

Dynamic characteristics of a 30-centimeter mercury ion thruster

NASA Technical Reports Server (NTRS)

Serafini, J. S.; Mantenieks, M. A.; Rawlin, V. K.

1975-01-01

The present work reports on measurements of the fluctuations in the beam current, discharge current, neutralizer keeper current, and discharge voltage of a 30-cm ion thruster made with 60Hz laboratory-type power supplies. The intensities of the fluctuations (ratio of the root-mean-square magnitude to time-average quantity) were found to depend significantly on the beam and magnetic baffle currents. The shape of the frequency spectra of the discharge plasma fluctuations was related to the beam and magnetic baffle currents. The predominant peaks of the beam and discharge current spectra occurred at frequencies less than 30 kilohertz. This discharge chamber resonance could be attributable to ion-acoustic wave phenomena. Cross-correlations of the discharge and beam currents indicated that the dependence on the magnetic baffle current was strong. The measurements revealed that the discharge current fluctuations directly contribute to the beam current fluctuations and that the power supply characteristics can modify these fluctuations.

Electric thruster research

NASA Technical Reports Server (NTRS)

Kaufman, H. R.; Robinson, R. S.

1981-01-01

The multipole discharge chamber of an electrostatic ion thruster is discussed. No reductions in discharge losses were obtained, despite repeated demonstration of anode potentials more positive than the bulk of the discharge plasma. The penalty associated with biased anode operation was reduced as the magnetic integral above the biased anodes was increased. The hollow cathode is discussed. The experimental configuration of the Hall current thruster had a uniform field throughout the ion generation and acceleration regions. To obtain reliable ion generation, it was necessary to reduce the magnetic field strength, to the point where excessive electron backflow was required to establish ion acceleration. The theoretical study of ion acceleration with closed electron drift paths resulted in two classes of solutions. One class has the continuous potential variation in the acceleration region that is normally associated with a Hall current accelerator. The other class has an almost discontinuous potential step near the anode end of the acceleration region. This step includes a significant fraction of the total acceleration potential difference.

Influence of the Oxygen Electrode Open Ratio and Electrolyte Evaporation on the Performance of Li-O2 Batteries.

PubMed

Mohazabrad, Farhad; Wang, Fangzhou; Li, Xianglin

2017-05-10

This study experimentally investigates and numerically simulates the influence of the cathode electrode open ratio (ratio of oxygen-opening area to the total electrode surface area) on the performance of Li-O 2 batteries at various discharge current densities. At the current density of 0.1 mA/cm 2 , the maximum discharge capacity is achieved at 25% open ratio among the tested open ratios (0-100%). As the open ratio increases from 25% to 100%, the specific discharge capacity decreases from 995 to 397 mA h/g carbon . A similar trend is observed at 0.3 mA/cm 2 , while the maximum discharge capacity is obtained at 3% open ratio among the tested open ratios. The model that assumes the electrode is always fully saturated by the electrolyte does not obtain similar trends with experimental results, while the model that considers electrolyte loss by evaporation and the volume change of the solid obtains the same trend with experimental observations. The open ratio governs not only availability of oxygen but also the evaporation of the electrolyte and the contact resistance. The faster evaporation of the electrolyte at a higher open ratio can be the main reason for the decrease of the discharge capacity, especially when the open ratio is relatively high (above 25%). Meanwhile, the contact resistance of the battery, measured by the electrochemical impedance spectroscopy (EIS), increases from 3.97 to 7.02 Ω when the open ratio increased from 3% to 95%. The increase of the Ohmic overpotential, however, is negligible (on the order of millivolts) because of the low discharge and charge current rates (on the order of 0.1 mA).

Contribution of river floods, hurricanes, and cold fronts to elevation change in a deltaic floodplain, northern Gulf of Mexico, USA

NASA Astrophysics Data System (ADS)

Bevington, Azure E.; Twilley, Robert R.; Sasser, Charles E.; Holm, Guerry O.

2017-05-01

Deltas are globally important locations of diverse ecosystems, human settlement, and economic activity that are threatened by reductions in sediment delivery, accelerated sea level rise, and subsidence. Here we investigated the relative contribution of river flooding, hurricanes, and cold fronts on elevation change in the prograding Wax Lake Delta (WLD). Sediment surface elevation was measured across 87 plots, eight times from February 2008 to August 2011. The high peak discharge river floods in 2008 and 2011 resulted in the greatest mean net elevation gain of 5.4 to 4.9 cm over each flood season, respectively. The highest deltaic wetland sediment retention (13.5% of total sediment discharge) occurred during the 2008 river flood despite lower total and peak discharge compared to 2011. Hurricanes Gustav and Ike resulted in a total net elevation gain of 1.2 cm, but the long-term contribution of hurricane derived sediments to deltaic wetlands was estimated to be just 22% of the long-term contribution of large river floods. Winter cold front passage resulted in a net loss in elevation that is equal to the elevation gain from lower discharge river floods and was consistent across years. This amount of annual loss in elevation from cold fronts could effectively negate the long-term land building capacity within the delta without the added elevation gain from both high and low discharge river floods. The current lack of inclusion of cold front elevation loss in most predictive numerical models likely overestimates the land building capacity in areas that experience similar forcings to WLD.

Self-pulsing in a low-current hollow cathode discharge: From Townsend to glow discharge

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

Qin, Yu; School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081; Xie, Kan, E-mail: xiekan@bit.edu.cn

We investigate the self-pulsing phenomenon of a low current cavity discharge in a cylindrical hollow cathode in pure argon. The waveforms of pulsed current and voltage are measured, and the time-averaged and time-resolved images of hollow cathode discharge are recorded by using high-speed intensified charge coupled device camera. The results show that the self-pulsing is a mode transition between low-current stage of Townsend discharge and high-current stage of glow discharge. During the self-pulsing, the current rising time relates to the dissipation of space charges, and the decay time relates to the reconstruction of the virtual anode by the accumulation ofmore » positive ions. Whether or not space charges can form and keep the virtual anode is responsible for the discharge mode and hence plays an important role in the self-pulsing phenomenon in low current hollow cathode discharge.« less

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.

A 16 MJ compact pulsed power system for electromagnetic launch

NASA Astrophysics Data System (ADS)

Dai, Ling; Zhang, Qin; Zhong, Heqing; Lin, Fuchang; Li, Hua; Wang, Yan; Su, Cheng; Huang, Qinghua; Chen, Xu

2015-07-01

This paper has established a compact pulsed power system (PPS) of 16 MJ for electromagnetic rail gun. The PPS consists of pulsed forming network (PFN), chargers, monitoring system, and current junction. The PFN is composed of 156 pulse forming units (PFUs). Every PFU can be triggered simultaneously or sequentially in order to obtain different total current waveforms. The whole device except general control table is divided into two frameworks with size of 7.5 m × 2.2 m × 2.3 m. It is important to estimate the discharge current of PFU accurately for the design of the whole electromagnetic launch system. In this paper, the on-state characteristics of pulse thyristor have been researched to improve the estimation accuracy. The on-state characteristics of pulse thyristor are expressed as a logarithmic function based on experimental data. The circuit current waveform of the single PFU agrees with the simulating one. On the other hand, the coaxial discharge cable is a quick wear part in PFU because the discharge current will be up to dozens of kA even hundreds of kA. In this article, the electromagnetic field existing in the coaxial cable is calculated by finite element method. On basis of the calculation results, the structure of cable is optimized in order to improve the limit current value of the cable. At the end of the paper, the experiment current wave of the PPS with the load of rail gun is provided.

A 16 MJ compact pulsed power system for electromagnetic launch.

PubMed

Dai, Ling; Zhang, Qin; Zhong, Heqing; Lin, Fuchang; Li, Hua; Wang, Yan; Su, Cheng; Huang, Qinghua; Chen, Xu

2015-07-01

This paper has established a compact pulsed power system (PPS) of 16 MJ for electromagnetic rail gun. The PPS consists of pulsed forming network (PFN), chargers, monitoring system, and current junction. The PFN is composed of 156 pulse forming units (PFUs). Every PFU can be triggered simultaneously or sequentially in order to obtain different total current waveforms. The whole device except general control table is divided into two frameworks with size of 7.5 m × 2.2 m × 2.3 m. It is important to estimate the discharge current of PFU accurately for the design of the whole electromagnetic launch system. In this paper, the on-state characteristics of pulse thyristor have been researched to improve the estimation accuracy. The on-state characteristics of pulse thyristor are expressed as a logarithmic function based on experimental data. The circuit current waveform of the single PFU agrees with the simulating one. On the other hand, the coaxial discharge cable is a quick wear part in PFU because the discharge current will be up to dozens of kA even hundreds of kA. In this article, the electromagnetic field existing in the coaxial cable is calculated by finite element method. On basis of the calculation results, the structure of cable is optimized in order to improve the limit current value of the cable. At the end of the paper, the experiment current wave of the PPS with the load of rail gun is provided.

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.

Discharge estimation from H-ADCP measurements in a tidal river subject to sidewall effects and a mobile bed

NASA Astrophysics Data System (ADS)

Sassi, M. G.; Hoitink, A. J. F.; Vermeulen, B.; Hidayat, null

2011-06-01

Horizontal acoustic Doppler current profilers (H-ADCPs) can be employed to estimate river discharge based on water level measurements and flow velocity array data across a river transect. A new method is presented that accounts for the dip in velocity near the water surface, which is caused by sidewall effects that decrease with the width to depth ratio of a channel. A boundary layer model is introduced to convert single-depth velocity data from the H-ADCP to specific discharge. The parameters of the model include the local roughness length and a dip correction factor, which accounts for the sidewall effects. A regression model is employed to translate specific discharge to total discharge. The method was tested in the River Mahakam, representing a large river of complex bathymetry, where part of the flow is intrinsically three-dimensional and discharge rates exceed 8000 m3 s-1. Results from five moving boat ADCP campaigns covering separate semidiurnal tidal cycles are presented, three of which are used for calibration purposes, whereas the remaining two served for validation of the method. The dip correction factor showed a significant correlation with distance to the wall and bears a strong relation to secondary currents. The sidewall effects appeared to remain relatively constant throughout the tidal cycles under study. Bed roughness length is estimated at periods of maximum velocity, showing more variation at subtidal than at intratidal time scales. Intratidal variations were particularly obvious during bidirectional flow conditions, which occurred only during conditions of low river discharge. The new method was shown to outperform the widely used index velocity method by systematically reducing the relative error in the discharge estimates.

The influence of anode position and structure on cusped field thruster

NASA Astrophysics Data System (ADS)

Niu, Xiang; Liu, Hui; Yang, Chiyu; Jiang, Wenjia; Yu, Daren; Ning, Zhongxi

2018-04-01

A cusped field thruster is a kind of electric propulsion device using multi-stage cusped fields to realize plasma discharges and produce thrust. A previous study showed that plasma discharges in this thruster are non-uniform. In this work, a multi-annulus anode is used to measure the radial distribution of anode current density at different anode positions. The experimental results reveal that some electrons may reach the anode along the axis after they accelerate from the final cusp regardless of the anode positions. To further validate this idea and find out the mechanism of this central path along the axis, the central part of the anode is replaced with ceramics. This results in an increase in the total current with larger contributions at larger radii. The current oscillations also get larger. This brief letter is helpful to further understand the movement of electrons in cusped field thrusters and provide guidance on reducing the non-uniform degree of current density.

A comparison between initial continuous currents of different types of upward lightning

NASA Astrophysics Data System (ADS)

Wang, D.; Sawada, N.; Takagi, N.

2009-12-01

We have observed the lightning to a wind turbine and its lightning-protection tower for four consecutive winter seasons from 2005 to 2009. Our observation items include (1) thunderstorm electrical fields and lightning-caused electric field changes at multi sites around the wind turbine, (2) electrical currents at the bottom of the wind turbine and its lightning protection tower, (3) normal video and high speed image of lightning optical channels. Totally, we have obtained the data for 42 lightning that hit either on wind turbine or its lightning protection tower or both. Among these 42 lightning, 38 are upward lightning and 2 are downward lightning. We found the upward lightning can be sub-classified into two types. Type 1 upward lightning are self-triggered from a high structure, while type 2 lightning are triggered by a discharge occurred in other places which could be either a cloud discharge or a cloud-to-ground discharge (other-triggered). In this study, we have compared the two types of upward lightning in terms of initial continuous current rise time, peak current and charge transferred to the ground. We found that the initial current of self-triggered lightning tends to rise significantly faster and to a bigger peak value than the other-triggered lightning, although both types of lightning transferred similar amount of charge to the ground.

Reversing-counterpulse repetitive-pulse inductive storage circuit

DOEpatents

Honig, E.M.

1987-02-10

A high-power reversing-counterpulse repetitive-pulse inductive storage and transfer circuit includes an opening switch, a main energy storage coil, a counterpulse capacitor and a small inductor. After counterpulsing the opening switch off, the counterpulse capacitor is recharged by the main energy storage coil before the load pulse is initiated. This gives the counterpulse capacitor sufficient energy for the next counterpulse operation, although the polarity of the capacitor's voltage must be reversed before that can occur. By using a current-zero switch as the counterpulse start switch, the capacitor is disconnected from the circuit (with a full charge) when the load pulse is initiated, preventing the capacitor from depleting its energy store by discharging through the load. After the load pulse is terminated by reclosing the main opening switch, the polarity of the counterpulse capacitor voltage is reversed by discharging the capacitor through a small inductor and interrupting the discharge current oscillation at zero current and peak reversed voltage. The circuit enables high-power, high-repetition-rate operation with reusable switches and features total control (pulse-to-pulse) over output pulse initiation, duration, repetition rate, and, to some extent, risetime. 10 figs.

Enhanced ozone production in a pulsed dielectric barrier discharge plasma jet with addition of argon to a He-O2 flow gas

NASA Astrophysics Data System (ADS)

Sands, Brian; Ganguly, Biswa; Scofield, James

2013-09-01

Ozone production in a plasma jet DBD driven with a 20-ns risetime unipolar pulsed voltage can be significantly enhanced using helium as the primary flow gas with an O2 coflow. The overvolted discharge can be sustained with up to a 5% O2 coflow at <20 kHz pulse repetition frequency at 13 kV applied voltage. Ozone production scales with the pulse repetition frequency up to a ``turnover frequency'' that depends on the O2 concentration, total gas flow rate, and applied voltage. For example, peak ozone densities >1016 cm-3 were measured with 3% O2 admixture and <3 W input power at a 12 kHz turnover frequency. A further increase in the repetition frequency results in increased discharge current and 777 nm O(5 P) emission, but decreased ozone production and is followed by a transition to a filamentary discharge mode. The addition of argon at concentrations >=5% reduces the channel conductivity and shifts the turnover frequency to higher frequencies. This results in increased ozone production for a given applied voltage and gas flow rate. Time-resolved Ar(1s5) and He(23S1) metastable densities were acquired along with discharge current and ozone density measurements to gain insight into the mechanisms of optimum ozone production.

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 - ...

Fast repetition rate (FRR) flasher

DOEpatents

Kolber, Zbigniew; Falkowski, Paul

1997-02-11

A fast repetition rate (FRR) flasher suitable for high flash photolysis including kinetic chemical and biological analysis. The flasher includes a power supply, a discharge capacitor operably connected to be charged by the power supply, and a flash lamp for producing a series of flashes in response to discharge of the discharge capacitor. A triggering circuit operably connected to the flash lamp initially ionizes the flash lamp. A current switch is operably connected between the flash lamp and the discharge capacitor. The current switch has at least one insulated gate bipolar transistor for switching current that is operable to initiate a controllable discharge of the discharge capacitor through the flash lamp. Control means connected to the current switch for controlling the rate of discharge of the discharge capacitor thereby to effectively keep the flash lamp in an ionized state between Successive discharges of the discharge capacitor. Advantageously, the control means is operable to discharge the discharge capacitor at a rate greater than 10,000 Hz and even up to a rate greater than about 250,000 Hz.

The challenge of home discharge with a total artificial heart: the La Pitie Salpetriere experience.

PubMed

Demondion, Pierre; Fournel, Ludovic; Niculescu, Michaela; Pavie, Alain; Leprince, Pascal

2013-11-01

The total artificial heart (TAH) helps to counteract the current decrease in heart donors and is likely to bridge patients to transplant under favourable conditions. Today's mobile consoles facilitate home discharge. The aim of this study was to report on the La Pitie Hospital experience with CardioWest TAH recipients, and more particularly, on generally successful outpatient' management. A retrospective analysis was performed on clinical and biological data from patients implanted with a TAH between December 2006 and July 2010 in a single institution. Morbi-mortality during hospital stay, number and causes of rehospitalizations, quality of life during home discharge, bridge to transplant results and survival have all been analysed. Twenty-seven patients were implanted with the CardioWest. Fifteen patients (55.5%) died during support. Prior to home discharge, the most frequent cause of death was multi-organ failure (46.6%). Twelve patients were discharged home from hospital within a median of 88 days [range 35-152, interquartile range 57] postimplantation. Mean rehospitalization rate was 1.2 by patient, on account of device infection (n = 7), technical problems with the console (n = 3) and other causes (n = 4). Between discharge and transplant, patients spent 87% of their support time out of hospital. All patients who returned home with the TAH were subsequently transplanted, and 1 died in post-transplant. Despite the morbidity and mortality occurring during the postimplantation period, home discharge with a TAH is possible. Portables drivers allow for a safe return home. Aside from some remaining weak points such as infectious complications or noise, CardioWest TAH allows for successful rehabilitation of graft candidates, and assures highly satisfactory transplant results.

Water flow and nutrient flux from five estuarine rivers along the southwest coast of Everglades National Park, Florida, 1997-2001

USGS Publications Warehouse

Levesque, V.A.

2004-01-01

Discharge and nutrient fluxes for five tidally affected streams were monitored and evaluated as a part of the U.S. Geological Survey Place-Based Studies Initiative and the U.S. Department of the Interior Critical Ecosystem Studies Initiative. Locations on Lostmans Creek, and Broad, Harney, Shark, and North Rivers were selected using the criterion that a large amount of the water that flows through Shark River Slough must pass these sites. Discharge and nutrient-concentration data collection started at the Broad, Harney, and Shark River stations in January 1997 and ended in early 2001. Discharge and nutrient-concentration data collection started at the Lostmans Creek and North River stations in April 1999 and ended in early 2001. Each station was equipped with a vertically oriented acoustic-velocity sensor, water-level pressure transducer, bottom water-temperature thermistor, and specific conductance four-electrode sensor. Data collected using a vessel-mounted acoustic discharge measurement system were used to calibrate regression models of the mean river velocities and the in-situ index velocities. Information from these stations, in conjunction with data from other ongoing studies, will help to determine environmental effects on the southwest coast estuaries as changes in water management of the Everglades National Park continue. Discharges from the Lostmans Creek, and Broad, Harney, Shark, and North River stations are influenced by semidiurnal tides, meteorological events, and surface- and ground-water inflow. Each of the five rivers is usually well mixed, having no greater than 500 microSiemens per centimeter at 25? Celsius difference in specific conductance from top to bottom during flood and ebb tides. Instantaneous flood discharges (water moving upstream) are typically of greater magnitude and shorter duration than instantaneous ebb discharges (water moving downstream). Instantaneous discharge data were filtered using a low-pass filter to remove predominant tidal frequencies, and the filtered data were used to compute daily mean and monthly mean residual discharges. Lostmans Creek, and Broad, Harney and Shark Rivers each contributed from 20 to 27 percent of the total measured discharge to the Gulf of Mexico, whereas North River contributed approximately 4 percent. The main discharge region of the Shark River Slough extends from as far north as Lostmans Creek to as far south as North River. North River discharge has similar response characteristics to the other four rivers measured, but with a lesser magnitude of discharge. Comparisons of monthly mean discharges from the Tamiami Canal flow control structures S-12-A, B, C, and D located on U.S. Highway 41 (Tamiami Trail) to the five station total monthly mean discharges indicate that the discharges from the five rivers are approximately 2 to 3 times the S-12-A, B, C, D discharges, and that the measured southwest coast discharge peaks lead the S-12-A, B, C, D discharge peaks by approximately 1 month. Residual total nitrogen and total phosphorus fluxes were estimated using linear regression models of discharge and flux. Monthly mean total nitrogen residual fluxes for the five southwest coast rivers ranged from approximately 0 to 390 short tons, whereas monthly mean total phosphorus residual fluxes ranged from approximately 0 to 6 short tons. Total nitrogen and total phosphorus residual fluxes at Lostmans Creek, and Broad, Harney, and Shark Rivers were similar in magnitude, each accounting for between 20 to 29 percent of the total measured residual flux. North River contributed between 3 to 4 percent of the total nitrogen and total phosphorus residual flux from the five rivers.

Particle based plasma simulation for an ion engine discharge chamber

NASA Astrophysics Data System (ADS)

Mahalingam, Sudhakar

Design of the next generation of ion engines can benefit from detailed computer simulations of the plasma in the discharge chamber. In this work a complete particle based approach has been taken to model the discharge chamber plasma. This is the first time that simplifying continuum assumptions on the particle motion have not been made in a discharge chamber model. Because of the long mean free paths of the particles in the discharge chamber continuum models are questionable. The PIC-MCC model developed in this work tracks following particles: neutrals, singly charged ions, doubly charged ions, secondary electrons, and primary electrons. The trajectories of these particles are determined using the Newton-Lorentz's equation of motion including the effects of magnetic and electric fields. Particle collisions are determined using an MCC statistical technique. A large number of collision processes and particle wall interactions are included in the model. The magnetic fields produced by the permanent magnets are determined using Maxwell's equations. The electric fields are determined using an approximate input electric field coupled with a dynamic determination of the electric fields caused by the charged particles. In this work inclusion of the dynamic electric field calculation is made possible by using an inflated plasma permittivity value in the Poisson solver. This allows dynamic electric field calculation with minimal computational requirements in terms of both computer memory and run time. In addition, a number of other numerical procedures such as parallel processing have been implemented to shorten the computational time. The primary results are those modeling the discharge chamber of NASA's NSTAR ion engine at its full operating power. Convergence of numerical results such as total number of particles inside the discharge chamber, average energy of the plasma particles, discharge current, beam current and beam efficiency are obtained. Steady state results for the particle number density distributions and particle loss rates to the walls are presented. Comparisons of numerical results with experimental measurements such as currents and the particle number density distributions are made. Results from a parametric study and from an alternative magnetic field design are also given.

The effects of normal current density and the plasma spatial structuring in argon DBDs

NASA Astrophysics Data System (ADS)

Shkurenkov, I. A.; Mankelevich, Y. A.; Rakhimova, T. V.

2011-01-01

This paper presents the results of theoretical studies of high-pressure dielectric barrier discharges (DBD) in argon. Two different DBDs at the megahertz and the kilohertz power frequency range were simulated. The effect of normal current density was obtained in the numerical model for both types of the discharge. The discharge of megahertz range was uniform over the radius. The increase in the discharge current is accompanied by increase in the discharge area. The discharge of kilohertz range is not uniform over the radius. The concentric ring formation was observed during calculations. The increase in the discharge current occurs due to increase in the number of rings and as a result in the discharge area. The developed 2D model is able to describe only the first stage of the filament formation - the formation of concentric plasma rings. The filament formation starts at the edge of the current channel and spreads to its centre. Both the effect of normal current density and the filaments formation are caused by the nonstationarity at the current channel boundary.

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.

Ozone kinetics in low-pressure discharges: vibrationally excited ozone and molecule formation on surfaces

NASA Astrophysics Data System (ADS)

Marinov, Daniil; Guerra, Vasco; Guaitella, Olivier; Booth, Jean-Paul; Rousseau, Antoine

2013-10-01

A combined experimental and modeling investigation of the ozone kinetics in the afterglow of pulsed direct current discharges in oxygen is carried out. The discharge is generated in a cylindrical silica tube of radius 1 cm, with short pulse durations between 0.5 and 2 ms, pressures in the range 1-5 Torr and discharge currents ˜40-120 mA. Time-resolved absolute concentrations of ground-state atoms and ozone molecules were measured simultaneously in situ, by two-photon absorption laser-induced fluorescence and ultraviolet absorption, respectively. The experiments were complemented by a self-consistent model developed to interpret the results and, in particular, to evaluate the roles of vibrationally excited ozone and of ozone formation on surfaces. It is found that vibrationally excited ozone, O_3^{*} , plays an important role in the ozone kinetics, leading to a decrease in the ozone concentration and an increase in its formation time. In turn, the kinetics of O_3^{*} is strongly coupled with those of atomic oxygen and O2(a 1Δg) metastables. Ozone formation at the wall does not contribute significantly to the total ozone production under the present conditions. Upper limits for the effective heterogeneous recombination probability of O atoms into ozone are established.

Studies on pulsed optogalvanic effect in Eu/Ne hollow cathode discharge.

PubMed

Saini, V K; Kumar, P; Dixit, S K; Nakhe, S V

2014-07-01

The optogalvanic (OG) effect has been observed in a Eu/Ne hollow cathode discharge lamp using pulsed laser irradiation. An OG spectrum is recorded in dye laser wavelength region 574–602 nm using a boxcar-averager. In total 41 atomic lines are observed. Of these, 38 lines are assigned to neon transitions. Two lines observed corresponding to wavelengths 576.519 and 601.815 nm are assigned to europium transitions; (4f 7 6s 2 , S 8 7/2 →4f 7 6s6p , zP 6 7/2 ) and (4f 7 6s 2 , S 8 7/2 →4f 7 6s6p , zP 8 9/2 ), respectively, and the remaining line at 582.475 nm could not be assigned. The effect of the discharge current on europium as well as neon OG signals is also studied. At moderate discharge current values, an extra positive peak is observed in neon OG signal for the transition (1s 5 →2p 2 ) at 588.189 nm, which is explained by Penning-ionization process using the quasi-resonant energy transfer interactions between excited neon and europium atoms lying in 2p 2 and D 10 9/2 states, respectively.

Humidity effects on surface dielectric barrier discharge for gaseous naphthalene decomposition

NASA Astrophysics Data System (ADS)

Abdelaziz, Ayman A.; Ishijima, Tatsuo; Seto, Takafumi

2018-04-01

Experiments are performed using dry and humid air to clarify the effects of water vapour on the characteristics of surface dielectric barrier discharge (SDBD) and investigate its impact on the performance of the SDBD for decomposition of gaseous naphthalene in air stream. The current characteristics, including the discharge and the capacitive currents, are deeply analyzed and the discharge mechanism is explored. The results confirmed that the humidity affected the microdischarge distribution without affecting the discharge mode. Interestingly, it is found that the water vapour had a significant influence on the capacitance of the reactor due to its deposition on the discharge electrode and the dielectric, which, in turn, affects the power loss in the dielectric and the total power consumed in the reactor. Thus, the factor of the humidity effect on the power loss in the dielectric should be considered in addition to its effect on the attachment coefficient. Additionally, there was an optimum level of the humidity for the decomposition of naphthalene in the SDBD, and its value depended on the gas composition, where the maximum naphthalene decomposition efficiency in O2/H2O is achieved at the humidity level ˜10%, which was lower than that obtained in air/H2O (˜28%). The results also revealed that the role of the humidity in the decomposition efficiency was not significant in the humidified O2 at high power level. This was attributed to the significant increase in oxygen-derived species (such as O atoms and O3) at high power, which was enough to overcome the negative effects of the humidity.

Fast repetition rate (FRR) flasher

DOEpatents

Kolber, Z.; Falkowski, P.

1997-02-11

A fast repetition rate (FRR) flasher is described suitable for high flash photolysis including kinetic chemical and biological analysis. The flasher includes a power supply, a discharge capacitor operably connected to be charged by the power supply, and a flash lamp for producing a series of flashes in response to discharge of the discharge capacitor. A triggering circuit operably connected to the flash lamp initially ionizes the flash lamp. A current switch is operably connected between the flash lamp and the discharge capacitor. The current switch has at least one insulated gate bipolar transistor for switching current that is operable to initiate a controllable discharge of the discharge capacitor through the flash lamp. Control means connected to the current switch for controlling the rate of discharge of the discharge capacitor thereby to effectively keep the flash lamp in an ionized state between successive discharges of the discharge capacitor. Advantageously, the control means is operable to discharge the discharge capacitor at a rate greater than 10,000 Hz and even up to a rate greater than about 250,000 Hz. 14 figs.

Boron ion beam generation utilizing lanthanum hexaboride cathodes: Comparison of vacuum arc and planar magnetron glow

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

Nikolaev, A. G.; Vizir, A. V.; Yushkov, G. Yu., E-mail: gyushkov@mail.ru

Boron ion beams are widely used for semiconductor ion implantation and for surface modification for improving the operating parameters and increasing the lifetime of machine parts and tools. For the latter application, the purity requirements of boron ion beams are not as stringent as for semiconductor technology, and a composite cathode of lanthanum hexaboride may be suitable for the production of boron ions. We have explored the use of two different approaches to boron plasma production: vacuum arc and planar high power impulse magnetron in self-sputtering mode. For the arc discharge, the boron plasma is generated at cathode spots, whereasmore » for the magnetron discharge, the main process is sputtering of cathode material. We present here the results of comparative test experiments for both kinds of discharge, aimed at determining the optimal discharge parameters for maximum yield of boron ions. For both discharges, the extracted ion beam current reaches hundreds of milliamps and the fraction of boron ions in the total extracted ion beam is as high as 80%.« less

Physical Kinetics of Electrons in a High-Voltage Pulsed High-Pressure Discharge with Cylindrical Geometry

NASA Astrophysics Data System (ADS)

Kozhevnikov, V. Yu.; Kozyrev, A. V.; Semeniuk, N. S.

2017-12-01

Results of theoretical modeling of the phenomenon of a high-voltage discharge in nitrogen at atmospheric pressure are presented, based on a consistent kinetic theory of the electrons. A mathematical model of a nonstationary high-pressure discharge has been constructed for the first time, based on a description of the electron component from first principles. The physical kinetics of the electrons are described with the help of the Boltzmann kinematic equation for the electron distribution function over momenta with only ionization and elastic collisions taken into account. A detailed spatiotemporal picture of a nonstationary discharge with runaway electrons under conditions of coaxial geometry of the gas diode is presented. The model describes in a self-consistent way both the process of formation of the runaway electron flux in the discharge and the influence of this flux on the rate of ionization processes in the gas. Total energy spectra of the electron flux incident on the anode are calculated. The obtained parameters of the current pulse of the beam of fast electrons correlate well with the known experimental data.

Optimum selection of an implantable secondary battery for an artificial heart by examination of the cycle life test.

PubMed

Okamoto, Eiji; Watanabe, Kazuya; Hashiba, Kunihiro; Inoue, Taku; Iwazawa, Eichi; Momoi, Masato; Hashimoto, Takuya; Mitamura, Yoshinori

2002-01-01

An implantable secondary battery is one of the key components in a total artificial heart system. Because a 2 year cycle life is required, the cycle life of the secondary battery as well as its charge and discharge properties are important parameters for selection of an appropriate battery. We carried out cycle life tests on four kinds of rechargeable batteries (a Ni-MH secondary battery, a Ni-Cd secondary battery, a Li-ion battery with a graphite anode, and a Li-ion battery with a nongraphitizable carbon electrode) to determine their suitability as implanted back-up batteries. Each of the batteries was charge/discharge cycled at 37 degrees C to 39 degrees C using a charge current of 1 C ampere, and they were each fully discharged under either pulsatile discharge loads, which mimicked pulsatile operation, or a nonpulsatile load equivalent to the average of the pulsatile loads. The two Li-ion batteries made by different manufacturers both met the minimum requirement of cycle life of more than 1,500 cycles, considering safety coefficient regardless of the discharge pattern. In addition, the temperature increase of these Li-ion batteries (3 degrees C) was lower than that of Ni-Cd and Ni-MH batteries (15-25 degrees C). Out of these four batteries, the two Li-ion batteries are the most suitable for use in a totally implantable artificial heart system.

Effects of coal-mine discharges on the quality of the Stonycreek River and its tributaries, Somerset and Cambria counties, Pennsylvania

USGS Publications Warehouse

Williams, Donald R.; Sams, James I.; Mulkerrin, Mary E.

1996-01-01

This report describes the results of a study by the U.S. Geological Survey, done in cooperation with the Somerset Conservation District, to locate and sample abandoned coal-mine discharges in the Stonycreek River Basin, to prioritize the mine discharges for remediation, and to determine the effects of the mine discharges on water quality of the Stonycreek River and its major tributaries. From October 1991 through November 1994, 270 abandoned coal-mine discharges were located and sampled. Discharges from 193 mines exceeded U.S. Environmental Protection Agency effluent standards for pH, discharges from 122 mines exceeded effluent standards for total-iron concentration, and discharges from 141 mines exceeded effluent standards for total-manganese concentration. Discharges from 94 mines exceeded effluent standards for all three constituents. Only 40 mine discharges met effluent standards for pH and concentrations of total iron and total manganese.A prioritization index (PI) was developed to rank the mine discharges with respect to their loading capacity on the receiving stream. The PI lists the most severe mine discharges in a descending order for the Stonycreek River Basin and for subbasins that include the Shade Creek, Paint Creek, Wells Creek, Quemahoning Creek, Oven Run, and Pokeytown Run Basins.Passive-treatment systems that include aerobic wetlands, compost wetlands, and anoxic limestone drains (ALD's) are planned to remediate the abandoned mine discharges. The successive alkalinity-producing-system treatment combines ALD technology with the sulfate reduction mechanism of the compost wetland to effectively remediate mine discharge. The water quality and flow of each mine discharge will determine which treatment system or combination of treatment systems would be necessary for remediation.A network of 37 surface-water sampling sites was established to determine stream-water quality during base flow. A series of illustrations show how water quality in the mainstem deteriorates downstream because of inflows from tributaries affected by acidic mine discharges. From the upstream mainstem site (site 801) to the outflow mainstem site (site 805), pH decreased from 6.8 to 4.2, alkalinity was completely depleted by inflow acidities, and total-iron discharges increased from 30 to 684 pounds per day. Total-manganese and total-sulfate discharges increased because neither constituent precipitates readily. Also, discharges of manganese and sulfate entering the mainstem from tributary streams have a cumulative effect.Oven Run and Pokeytown Run are two small tributary streams significantly affected by acidic mine drainage (AMD) that flow into the Stonycreek River near the town of Hooversville. The Pokeytown Run inflow is about 0.5 mile downstream from the Oven Run inflow. These two streams are the first major source of AMD flowing into the Stonycreek River. Data collected on the Stonycreek River above the Oven Run inflow and below the Pokeytown Run inflow show a decrease in pH from 7.6 to 5.1, a decrease in alkalinity concentration from 42 to 2 milligrams per liter, an increase in total sulfate discharge from 18 to 41 tons per day, and an increase in total iron discharge from 29 to 1,770 pounds per day. Data collected at three mainstem sites on the Stonycreek River below Oven Run and Pokeytown Run show a progressive deterioration in river water quality from AMD.Shade Creek and Paint Creek are other tributary streams to the Stonycreek River that have a significant negative effect on water quality of the Stonycreek River. One third of the abandoned-mine discharges sampled were in the Shade Creek and Paint Creek Basins.

Self-discharge characteristic and mechanism of single-phase PuNi3-, Gd2Co7-, and Pr5Co19-type Nd-Mg-Ni-based alloys

NASA Astrophysics Data System (ADS)

Jia, Zeru; Zhang, Lu; Zhao, Yumeng; Cao, Juan; Li, Yuan; Dong, Zhentao; Wang, Wenfeng; Han, Shumin

2017-12-01

To decrease the self-discharge rate of the nickel metal hydride batteries, the self-discharge characteristic and mechanism of single-phase PuNi3-, Gd2Co7-, and Pr5Co19-type Nd-Mg-Ni-based alloys are studied from the perspective of structure in this work. It is found that the self-discharge rate of the alloy electrodes gradually increases with a rising [NdNi5]/[NdMgNi4] subunit ratio. The factors resulting in reversible and irreversible self-discharge are analyzed by electrochemical pressure-composition isotherms, Tafel and SEM measurements. Electrochemical P-C isotherms show that with the increasing [NdNi5]/[NdMgNi4] subunit ratio, the hydrogen desorption plateau pressure sharply elevates, leading to less stability of the corresponding hydride and more reversible self-discharge of the alloys; whereas, corrosion current density of the three alloy electrodes gradually decreases and SEM shows that the amount of hydroxide accumulating on the alloy surface diminishes, indicating the oxidation/corrosion degree alleviates and less irreversible self-discharge with the higher [NdNi5]/[NdMgNi4] ratio. By calculating the proportion of reversible and irreversible self-discharge in total capacity loss, we find that the reversible self-discharge is nearly more than 90% for the three single-phase alloys, while irreversible self-discharge is less than 10%, which illustrates that reversible self-discharge is the dominate factor in self-discharge of Nd-Mg-Ni-based alloys in this study.

Plasma source for spacecraft potential control

NASA Technical Reports Server (NTRS)

Olsen, R. C.

1983-01-01

A stable electrical ground which enables the particle spectrometers to measure the low energy particle populations was investigated and the current required to neutralize the spacecraft was measured. In addition, the plasma source for potential control (PSPO C) prevents high charging events which could affect the spacecraft electrical integrity. The plasma source must be able to emit a plasma current large enough to balance the sum of all other currents to the spacecraft. In ion thrusters, hollow cathodes provide several amperes of electron current to the discharge chamber. The PSPO C is capable of balancing the net negative currents found in eclipse charging events producing 10 to 100 microamps of electron current. The largest current required is the ion current necessary to balance the total photoelectric current.

The development of shock wave overpressure driven by channel expansion of high current impulse discharge arc

NASA Astrophysics Data System (ADS)

Xiong, Jia-ming; Li, Lee; Dai, Hong-yu; Wu, Hai-bo; Peng, Ming-yang; Lin, Fu-chang

2018-03-01

During the formation of a high current impulse discharge arc, objects near the discharge arc will be strongly impacted. In this paper, a high power, high current gas switch is used as the site of the impulse discharge arc. The explosion wave theory and the arc channel energy balance equation are introduced to analyze the development of the shock wave overpressure driven by the high current impulse discharge arc, and the demarcation point of the arc channel is given, from which the energy of the arc channel is no longer converted into shock waves. Through the analysis and calculation, it is found that the magnitude of the shock wave overpressure caused by impulse discharge arc expansion is closely related to the arc current rising rate. The arc shock wave overpressure will undergo a slow decay process and then decay rapidly. The study of this paper will perform the function of deepening the understanding of the physical nature of the impulse arc discharge, which can be used to explain the damage effect of the high current impulse discharge arc.

Comparison of runaway electron generation parameters in small, medium-sized and large tokamaks—A survey of experiments in COMPASS, TCV, ASDEX-Upgrade and JET

NASA Astrophysics Data System (ADS)

Plyusnin, V. V.; Reux, C.; Kiptily, V. G.; Pautasso, G.; Decker, J.; Papp, G.; Kallenbach, A.; Weinzettl, V.; Mlynar, J.; Coda, S.; Riccardo, V.; Lomas, P.; Jachmich, S.; Shevelev, A. E.; Alper, B.; Khilkevitch, E.; Martin, Y.; Dux, R.; Fuchs, C.; Duval, B.; Brix, M.; Tardini, G.; Maraschek, M.; Treutterer, W.; Giannone, L.; Mlynek, A.; Ficker, O.; Martin, P.; Gerasimov, S.; Potzel, S.; Paprok, R.; McCarthy, P. J.; Imrisek, M.; Boboc, A.; Lackner, K.; Fernandes, A.; Havlicek, J.; Giacomelli, L.; Vlainic, M.; Nocente, M.; Kruezi, U.; COMPASS Team; TCV Team; ASDEX-Upgrade Team; EUROFusion MST1 Team; contributors, JET

2018-01-01

This paper presents a survey of the experiments on runaway electrons (RE) carried out recently in frames of EUROFusion Consortium in different tokamaks: COMPASS, ASDEX-Upgrade, TCV and JET. Massive gas injection (MGI) has been used in different scenarios for RE generation in small and medium-sized tokamaks to elaborate the most efficient and reliable ones for future RE experiments. New data on RE generated at disruptions in COMPASS and ASDEX-Upgrade was collected and added to the JET database. Different accessible parameters of disruptions, such as current quench rate, conversion rate of plasma current into runaways, etc have been analysed for each tokamak and compared to JET data. It was shown, that tokamaks with larger geometrical sizes provide the wider limits for spatial and temporal variation of plasma parameters during disruptions, thus extending the parameter space for RE generation. The second part of experiments was dedicated to study of RE generation in stationary discharges in COMPASS, TCV and JET. Injection of Ne/Ar have been used to mock-up the JET MGI runaway suppression experiments. Secondary RE avalanching was identified and quantified for the first time in the TCV tokamak in RE generating discharges after massive Ne injection. Simulations of the primary RE generation and secondary avalanching dynamics in stationary discharges has demonstrated that RE current fraction created via avalanching could achieve up to 70-75% of the total plasma current in TCV. Relaxations which are reminiscent the phenomena associated to the kinetic instability driven by RE have been detected in RE discharges in TCV. Macroscopic parameters of RE dominating discharges in TCV before and after onset of the instability fit well to the empirical instability criterion, which was established in the early tokamaks and examined by results of recent numerical simulations.

Multiple current peaks in room-temperature atmospheric pressure homogenous dielectric barrier discharge plasma excited by high-voltage tunable nanosecond pulse in air

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

Yang, De-Zheng; Wang, Wen-Chun; Zhang, Shuai

2013-05-13

Room temperature homogenous dielectric barrier discharge plasma with high instantaneous energy efficiency is acquired by using nanosecond pulse voltage with 20-200 ns tunable pulse width. Increasing the voltage pulse width can lead to the generation of regular and stable multiple current peaks in each discharge sequence. When the voltage pulse width is 200 ns, more than 5 organized current peaks can be observed under 26 kV peak voltage. Investigation also shows that the organized multiple current peaks only appear in homogenous discharge mode. When the discharge is filament mode, organized multiple current peaks are replaced by chaotic filament current peaks.

Numerical investigation of the effect of driving voltage pulse shapes on the characteristics of low-pressure argon dielectric barrier discharge

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

Eslami, E., E-mail: eeslami@iust.ac.ir; Barjasteh, A.; Morshedian, N.

2015-06-15

In this work, we numerically compare the effect of a sinusoidal, triangular, and rectangular pulsed voltage profile on the calculated particle production, electric current, and gas voltage in a dielectric barrier discharge. The total argon gas pressure of 400 Pa, the distance between dielectrics of 5 mm, the dielectric thickness of 0.7 mm, and the temperature of T = 300 K were considered as input parameters. The different driving voltage pulse shapes (triangular, rectangular, and sinusoidal) are considered as applied voltage with a frequency of 7 kHz and an amplitude of 700 V peak to peak. It is shown thatmore » applying a rectangular voltage, as compared with a sinusoidal or triangle voltage, increases the current peak, while the peak width is decreased. Higher current density is related to high production of charged particles, which leads to the generation of some highly active species, such as Ar* (4s level), and Ar** (4p level) in the gap.« less

Impact of freshwater runoff on physical oceanography and plankton distribution in a Western Norwegian fjord: an experiment with a controlled discharge from a hydroelectric power plant

NASA Astrophysics Data System (ADS)

Kaartvedt, Stein; Svendsen, Harald

1990-10-01

Investigations were carried out in a 20-km long fjord branch prior to, during, and partly after a 51-h controlled discharge from a hydroelectric power plant. The freshwater runoff (230 m 3 s -1) generated an estuarine circulation which was most prominent along the mid-axis of the fjord. High velocities were recorded both in the outgoing surface current, with a maximum of 1 m s -1 (10 km downstream of the power plant), and in a compensatory current (registration at 10-m depth) with a maximum of 0·6 m s -1 (3 km downstream). Velocities were low at 5-m depth. During discharge, salinity increased in the surface layer and decreased at a depth of several metres because of more extensive mixing. Phytoplankton was partly flushed out in the upper layers throughout the fjord branch, but abundance increased in deeper layers in an outer station, and the horizontal patchiness increased. The vertical centre of zooplankton biomass descended significantly during running of the plant. Biomass maxima in the ingoing compensation current indicate net zooplankton import during running of the power plant, but no change in total zooplankton biomass in the fjord branch was found during this experiment.

Comparison between Trichel pulse in negative corona and self-pulsing in other configurations

NASA Astrophysics Data System (ADS)

Xia, Qing; Zhang, Yu; He, Feng; Qin, Yu; Jiang, Zhaorui; Ouyang, Jiting

2018-02-01

We present here a comparison study on self-pulsing phenomena in negative corona, hollow cathode discharges (HCD) and parallel-plate discharge in air. The voltage-current (V-I) curve, the waveforms of self-pulsed currents, and the time-resolved images of the pulsed discharge are measured under various operating conditions. It is experimentally evidenced that the Trichel pulse in a negative corona and the self-pulsing in HCD and/or parallel-plate discharge have similar features as well as spatial-temporal developing process. It is suggested that they should have a similar mechanism that the pulsing reflects the mode transition of discharge between the low-current Townsend and the high-current normal glow. The pulse rising corresponds to the breakdown and formation of temporal glow discharge in a background of low-current Townsend discharge, while the decay edge relates to the transition back to Townsend discharge. The pulse interval is the re-building process of the space charge layer of high density to ensure the glow breakdown.

The channel radius and energy of cloud-to-ground lightning discharge plasma with multiple return strokes

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

Wang, Xuejuan; Yuan, Ping; Cen, Jianyong

2014-03-15

Using the spectra of a cloud-to-ground (CG) lightning flash with multiple return strokes and combining with the synchronous radiated electrical field information, the linear charge density, the channel radius, the energy per unit length, the thermal energy, and the energy of dissociation and ionization in discharge channel are calculated with the aid of an electrodynamic model of lightning. The conclusion that the initial radius of discharge channel is determined by the duration of the discharge current is confirmed. Moreover, the correlativity of several parameters has been analyzed first. The results indicate that the total intensity of spectra is positive correlatedmore » to the channel initial radius. The ionization and thermal energies have a linear relationship, and the dissociation energy is correlated positively to the ionization and thermal energies, the energy per unit length is in direct proportion to the square of initial radius in different strokes of one CG lightning.« less

Capillary Discharge Soft X-ray Laser Experiments at Air Force Research Laboratory

NASA Astrophysics Data System (ADS)

Ruden, E. L.; Gale, D. G.

1997-11-01

The Air Force Research Laboratory (previously Phillips Laboratory) is presently attempting to reproduce the high gain laser results of J.J. Rocca's capillary discharge z-pinch pumped 46.9 nm Ne-like Ar laser. This poster presents progress to date at measuring our laser's intensity and gain. The capillary circuit consists of a low inductance 3 nH water capacitor discharged by a coaxial spark gap into a 12 cm long, 4 mm ID plastic capillary. The capillary is supplied with 39 kA of current with a 20 ns risetime. The principle radiation diagnostic consists of a VUV monochrometer coupled to a custom high speed vacuum X-ray diode with an aluminum cathode. The signal is recorded on a fast transient digitizer (Tektronix SCD 5000). The total detector system's analog bandwidth is about 3 GHz.

Improving transition of care for veterans after total joint replacement.

PubMed

Green, Uthona R; Dearmon, Valorie; Taggart, Helen

2015-01-01

Patients transitioning from hospital to home are at risk for readmission to the hospital. Readmissions are costly and occur too often. Standardized discharge education processes have shown to decrease readmissions. The purpose of this quality improvement project was to utilize evidence-based practice changes to decrease 30-day all-cause readmissions after total joint replacement. Review of literature revealed that improved discharge education can decrease unnecessary readmissions after discharge. A quality improvement project was developed including standardized total joint replacement discharge education, teach-back education methodology, and improved postdischarge telephone follow-up. The quality improvement project was initiated and outcomes were evaluated. Improving coordination of the discharge process, enhanced education for patients/caregivers, and postdischarge follow-up decreased total joint replacement readmissions.

Sediment transport and effective discharge of the North Platte, South Platte, and Platte Rivers in Nebraska

USGS Publications Warehouse

Kircher, J.E.

1981-01-01

Sediment discharge was computed for four locations along the North Platte, South Platte, and the Platte Rivers between North Platte and Grand Island, Nebraska in order to determine the effective discharge. The total-sediment discharge was computed by the Colby method and modified Einstein method so that comparisons could be made with the measured total-sediment discharge. The results agreed closely. The Colby method is the simplest and most convenient to use. The mean annual total-sediment discharge for the four sites investigated ranged from 150 tons per day for the South Platte River at North Platte to 1,260 tons per day for the Platte River near Grand Island. The effective discharge at the sites ranged from 41 to 158 cubic meters per second. The probability of the effective discharge being equaled or exceeded ranged from 1 to 30 percent for the four sites. (USGS)

On the physical processes ruling an atmospheric pressure air glow discharge operating in an intermediate current regime

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

Prevosto, L., E-mail: prevosto@waycom.com.ar; Mancinelli, B.; Chamorro, J. C.

2015-02-15

Low-frequency (100 Hz), intermediate-current (50 to 200 mA) glow discharges were experimentally investigated in atmospheric pressure air between blunt copper electrodes. Voltage–current characteristics and images of the discharge for different inter-electrode distances are reported. A cathode-fall voltage close to 360 V and a current density at the cathode surface of about 11 A/cm{sup 2}, both independent of the discharge current, were found. The visible emissive structure of the discharge resembles to that of a typical low-pressure glow, thus suggesting a glow-like electric field distribution in the discharge. A kinetic model for the discharge ionization processes is also presented with the aim of identifying themore » main physical processes ruling the discharge behavior. The numerical results indicate the presence of a non-equilibrium plasma with rather high gas temperature (above 4000 K) leading to the production of components such as NO, O, and N which are usually absent in low-current glows. Hence, the ionization by electron-impact is replaced by associative ionization, which is independent of the reduced electric field. This leads to a negative current-voltage characteristic curve, in spite of the glow-like features of the discharge. On the other hand, several estimations show that the discharge seems to be stabilized by heat conduction; being thermally stable due to its reduced size. All the quoted results indicate that although this discharge regime might be considered to be close to an arc, it is still a glow discharge as demonstrated by its overall properties, supported also by the presence of thermal non-equilibrium.« less

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.

Ecton processes in the generation of pulsed runaway electron beams in a gas discharge

NASA Astrophysics Data System (ADS)

Mesyats, G. A.

2017-09-01

As was shown earlier for pulsed discharges that occur in electric fields rising with extremely high rates (1018 V/(cm s)) during the pulse rise time, the electron current in a vacuum discharge is lower than the current of runaway electrons in an atmospheric air discharge in a 1-cm-long gap. In this paper, this is explained by that the field emission current from cathode microprotrusions in a gas discharge is enhanced due to gas ionization. This hastens the initiation of explosive electron emission, which occurs within 10-11 s at a current density of up to 1010 A/cm2. Thereafter, a first-type cathode spot starts forming. The temperature of the cathode spot decreases due to heat conduction, and the explosive emission current ceases. Thus, the runaway electron current pulse is similar in nature to the ecton phenomenon in a vacuum discharge.

Development of internal magnetic probe for current density profile measurement in Versatile Experiment Spherical Torus

NASA Astrophysics Data System (ADS)

Yang, J.; Lee, J. W.; Jung, B. K.; Chung, K. J.; Hwang, Y. S.

2014-11-01

An internal magnetic probe using Hall sensors to measure a current density profile directly with perturbation of less than 10% to the plasma current is successfully operated for the first time in Versatile Experiment Spherical Torus (VEST). An appropriate Hall sensor is chosen to produce sufficient signals for VEST magnetic field while maintaining the small size of 10 mm in outer diameter. Temperature around the Hall sensor in a typical VEST plasma is regulated by blown air of 2 bars. First measurement of 60 kA VEST ohmic discharge shows a reasonable agreement with the total plasma current measured by Rogowski coil in VEST.

Geomorphic and hydrologic assessment of erosion hazards at the Norman municipal landfill, Canadian River floodplain, central Oklahoma

USGS Publications Warehouse

Curtis, Jennifer A.; Whitney, John W.

2003-01-01

The Norman, Oklahoma, municipal landfill closed in 1985 after 63 years of operation, because it was identified as a point source of hazardous leachate composed of organic and inorganic compounds. The landfill is located on the floodplain of the Canadian River, a sand-bed river characterized by erodible channel boundaries and by large variation in mean monthly discharges. In 1986, floodwaters eroded riprap protection at the southern end of the landfill and penetrated the landfill's clay cap, thereby exposing the landfill contents. The impact of this moderate-magnitude flood event (Q12) was the catalyst to investigate erosion hazards at the Norman landfill. This geomorphic investigation analyzed floodplain geomorphology and historical channel changes, flood-frequency distributions, an erosion threshold, the geomorphic effectiveness of discharge events, and other factors that influence erosion hazards at the landfill site. The erosion hazard at the Norman landfill is a function of the location of the landfill with respect to the channel thalweg, erosional resistance of the channel margins, magnitude and duration of discrete discharge events, channel form and hydraulic geometry, and cumulative effects related to a series of discharge events. Based on current climatic conditions and historical channel changes, a minimum erosion threshold is set at bankfull discharge (Q = 572 m3/s). The annual probability of exceeding this threshold is 0.53. In addition, this analysis indicates that peak stream power is less informative than total energy expenditures when estimating the erosion potential or geomorphic effectiveness of discrete discharge events. On the Canadian River, long-duration, moderate-magnitude floods can have larger total energy expenditures than shorter-duration, high-magnitude floods and therefore represent the most serious erosion hazard to floodplain structures.

Experiments Using Local Helicity Injectors in the Lower Divertor Region as the Majority Current Drive in a Tokamak Plasma

NASA Astrophysics Data System (ADS)

Perry, Justin M.

Local helicity injection (LHI) is a non-solenoidal current drive capable of achieving high-Ip tokamak startup with a relatively compact and non-invasive array of current injectors in the plasma scrape-off layer. The choice of injector location within the edge region is flexible, but has a profound influence on the nature of the current drive in LHI discharges. Past experiments on the Pegasus ST with injection on the low-field-side near the outboard midplane produced plasmas dominated by inductive drive resulting primarily from plasma geometry evolution over the discharge. Recent experiments with injection on the high-field- side in the lower divertor region produce plasmas dominated by helicity injection current drive, with relatively static plasma geometry, and thus negligible inductive drive. Plasma current up to 200 kA is driven with helicity injection as the dominant current drive using a pair of 4 cm2 area injectors sourcing 8 kA of total injected current. Steady sustainment with LHI current drive alone is demonstrated, with 100 kA sustained for 18 ms. Maximum achievable plasma current is found to scale approximately linearly with a plasma-geometry- normalized form of the effective loop voltage from LHI, Vnorm = AinjVinj/Rinj, where A inj is the total injector area, Vinj is the injector bias voltage, and Rinj is the major radius of the injectors. A newly-discovered MHD regime for LHI-driven plasmas is described, in which the large-amplitude n = 1 fluctuations at 20-50 kHz which are generally dominant during LHI are abruptly reduced by an order of magnitude on the outboard side. High frequency fluctuations ( f > 400 kHz) increase inside the plasma edge at the same time. This regime results in improved plasma current and pervasive changes to plasma behavior, and may suggest short wavelength turbulence as a current drive mechanism during LHI.

Formation of a spark discharge in an inhomogeneous electric field with current limitation by a large ballast Resistance

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

Baldanov, B. B., E-mail: baibat@mail.ru

2016-01-15

Results of studies of a spark discharge initiated in argon in a point–plane electrode gap with limitation of the discharge current by a large ballast resistance are presented. It is shown that the current flowing through the plasma channel of such a low-current spark has the form of periodic pulses. It is experimentally demonstrated that, when a low-current spark transforms into a constricted glow discharge, current pulses disappear, the spatial structure of the cathode glow changes abruptly, and a brightly glowing positive plasma column forms in the gap.

Passive control of temperature excursion and uniformity in high-energy Li-ion battery packs at high current and ambient temperature

NASA Astrophysics Data System (ADS)

Kizilel, R.; Lateef, A.; Sabbah, R.; Farid, M. M.; Selman, J. R.; Al-Hallaj, S.

A strategy for portable high-power applications with a controlled thermal environment has been developed and has demonstrated the advantage of using the novel phase change material (PCM) thermal management systems over conventional active cooling systems. A passive thermal management system using PCM for Li-ion batteries is tested for extreme conditions, such as ambient temperature of 45 °C and discharge rate of 2.08 C-rate (10 A). Contrary to Li-ion packs without thermal management system, high-energy packs with PCM are discharged safely at high currents and degrading rate of capacity of the Li-ion packs lowered by half. Moreover, the compactness of the packs not only decreases the volume occupied by the packs and its associated complex cooling system, but also decreases the total weight for large power application.

A voltage-controlled capacitive discharge method for electrical activation of peripheral nerves.

PubMed

Rosellini, Will M; Yoo, Paul B; Engineer, Navzer; Armstrong, Scott; Weiner, Richard L; Burress, Chester; Cauller, Larry

2011-01-01

A voltage-controlled capacitive discharge (VCCD) method was investigated as an alternative to rectangular stimulus pulses currently used in peripheral nerve stimulation therapies.  In two anesthetized Gottingen mini pigs, the threshold (total charge per phase) for evoking a compound nerve action potential (CNAP) was compared between constant current (CC) and VCCD methods. Electrical pulses were applied to the tibial and posterior cutaneous femoralis nerves using standard and modified versions of the Medtronic 3778 Octad.  In contrast to CC stimulation, the combined application of VCCD pulses with a modified Octad resulted in a marked decrease (-73 ± 7.4%) in the stimulation threshold for evoking a CNAP. This was consistent for different myelinated fiber types and locations of stimulation.  The VCCD method provides a highly charge-efficient means of activating myelinated fibers that could potentially be used within a wireless peripheral nerve stimulator system. © 2011 International Neuromodulation Society.

Dynamic characteristic of a 30-cm mercury ion thruster

NASA Technical Reports Server (NTRS)

Serafini, J. S.; Mantenieks, M. A.; Rawlin, V. K.

1975-01-01

Measurements of the fluctuations of the discharge and beam plasmas of a 30 centimeter ion thruster were performed using 60 Hertz laboratory type power supplies. The time-varying properties of the discharge voltage and current, the ion beam current, and neutralizer keeper current were measured. The intensities of the fluctuations were found to depend on the beam and magnetic baffle currents. The shape of the frequency spectra of the discharge plasma fluctuations was found to be related to the beam and magnetic baffle currents. The measurements indicated that the discharge current fluctuations directly contribute to the beam current fluctuations and that the power supply characteristics modify these fluctuations.

High-current discharge channel contraction in high density gas

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

Rutberg, Ph. G.; Bogomaz, A. A.; Pinchuk, M. E.

Research results for discharges at current amplitudes of 0.5-1.6 MA and current rise rate of {approx}10{sup 10} A/s are presented. The discharge is performed in the hydrogen environment at the initial pressure of 5-35 MPa. Initiation is implemented by a wire explosion. The time length of the first half-period of the discharge current is 70-150 {mu}s. Under such conditions, discharge channel contraction is observed; the contraction is followed by soft x-ray radiation. The phenomena are discussed, which are determined by high density of the gas surrounding the discharge channel. These phenomena are increase of the current critical value, where themore » channel contraction begins and growth of temperature in the axis region of the channel, where the initial density of the gas increases.« less

On-line Monitoring Device for High-voltage Switch Cabinet Partial Discharge Based on Pulse Current Method

NASA Astrophysics Data System (ADS)

Y Tao, S.; Zhang, X. Z.; Cai, H. W.; Li, P.; Feng, Y.; Zhang, T. C.; Li, J.; Wang, W. S.; Zhang, X. K.

2017-12-01

The pulse current method for partial discharge detection is generally applied in type testing and other off-line tests of electrical equipment at delivery. After intensive analysis of the present situation and existing problems of partial discharge detection in switch cabinets, this paper designed the circuit principle and signal extraction method for partial discharge on-line detection based on a high-voltage presence indicating systems (VPIS), established a high voltage switch cabinet partial discharge on-line detection circuit based on the pulse current method, developed background software integrated with real-time monitoring, judging and analyzing functions, carried out a real discharge simulation test on a real-type partial discharge defect simulation platform of a 10KV switch cabinet, and verified the sensitivity and validity of the high-voltage switch cabinet partial discharge on-line monitoring device based on the pulse current method. The study presented in this paper is of great significance for switch cabinet maintenance and theoretical study on pulse current method on-line detection, and has provided a good implementation method for partial discharge on-line monitoring devices for 10KV distribution network equipment.

Dual-frequency glow discharges in atmospheric helium

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

Huang, Xiaojiang; Guo, Ying; Magnetic Confinement Fusion Research Center, Ministry of Education of the People's Republic of China, Shanghai 201620

2015-10-15

In this paper, the dual-frequency (DF) glow discharges in atmospheric helium were experimented by electrical and optical measurements in terms of current voltage characteristics and optical emission intensity. It is shown that the waveforms of applied voltages or discharge currents are the results of low frequency (LF) waveforms added to high frequency (HF) waveforms. The HF mainly influences discharge currents, and the LF mainly influences applied voltages. The gas temperatures of DF discharges are mainly affected by HF power rather than LF power.

Efficiency of lithium pacemaker batteries as a function of discharge rate and iodine:P2VP cathode composition

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

Helgeson, W.D.; Fester, K.E.

1980-01-01

Electrochemical discharge data for Li/I/sub 2/-P2VP pacemaker batteries at various discharge currents show the efficiency of the battery to be a function of discharge current. Depending on the iodine:P2VP cathode composition, the optimum current drain occurs between discharge currents of 100 to 200 /mu/a. As current drain is reduced to pacemaker application drains, 15-25 /mu/a, the efficiency of the Li/I/sub 2/-P2VP battery decreases. The loss in efficiency at pacemaker rates is attributed primarily to self-discharge. The efficiency of Li/I/sub 2/-P2VP batteries is improved by increasing the percent of iodine in the cathode. I/sub 2/:P2VP weight ratios of 10:1, 15:1 andmore » 20:1 have been discharged at various currents and the data indicate that there is significant improvement in efficiency at pacemaker rate in going from 10:1 to 20:1 cathode weight ratio. 2 refs.« less

The effectiveness of inpatient physical therapy compared to outpatient physical therapy in older adults after total hip replacement in the post-discharge period: a systematic review.

PubMed

Klugarova, Jitka; Klugar, Miloslav; Mareckova, Jana; Gallo, Jiri; Kelnarova, Zuzana

2016-01-01

Total hip replacement is the most effective and safest method for treating severe degenerative, traumatic and other diseases of the hip joint. Total hip replacement can reliably relieve pain and improve function in the majority of patients for a period of 15 to 20 years or more postoperatively. Physical therapy follows each total hip replacement surgery. Physical therapy protocols after total hip replacement in the post-discharge period vary widely in terms of setting (inpatient, outpatient), content (the particular set of exercises used), and frequency (e.g. daily versus twice a week). In current literature, there is no systematic review which has compared the effectiveness of inpatient and outpatient physical therapy in patients after total hip replacement in the post-discharge period. The objective of this systematic review was to compare the effectiveness of inpatient physical therapy with outpatient physical therapy on the quality of life and gait measures in older adults after total hip replacement in the post-discharge period. This review considered studies that include older adults (over 65 years) who have had total hip replacement and are in the post-discharge period. Adults with bilateral or multiple simultaneous surgeries and also patients who have had hemiarthroplasty of the hip joint were excluded.This review considered studies that included any type of physical therapy delivered in inpatient settings provided by professionals with education in physical therapy. Inpatient physical therapy delivered at any frequency and over any duration was included.This review considered studies that included as a comparator any type of physical therapy delivered in outpatient settings provided by professionals with education in physical therapy or no physical therapy.This review considered studies that included the following primary and secondary outcomes. The primary outcome was quality of life, assessed by any validated assessment tool. The secondary outcome was measures of gait assessed by any valid methods.This review considered both experimental and observational study designs including randomized controlled trials, non-randomized controlled trials, quasi-experimental, before and after studies, prospective and retrospective cohort studies, case control studies and analytical cross sectional studies for inclusion. The search strategy aimed to find both published and unpublished studies. A three-step search strategy was utilized in 12 databases. Studies published in all languages and any date were considered for inclusion in this review. Assessment of methodological quality was not conducted as no studies were identified that met the inclusion criteria. Data extraction and synthesis was not performed because no studies were included in this systematic review. During to the three-step search strategy 4330 papers were identified. The primary and secondary reviewer independently retrieved 42 potentially relevant papers according to the inclusion criteria by title and abstract screening. Following assessment of full text all of the retrieved papers were excluded based on the inclusion criteria. There is no scientific evidence comparing the effectiveness of inpatient physical therapy with outpatient physical therapy in older patients after total hip replacement in the post-discharge period. This systematic review has identified gaps in the literature for comparing the effectiveness of inpatient physical therapy with and outpatient physical therapy on the quality of life and gait measures in older adults after total hip replacement in the post-discharge period. Prospective randomized double blind multicenter controlled trials are needed to answer this important clinical question.

Development of a Specific Impulse Balance for a Pulsed Capillary Discharge (Preprint)

DTIC Science & Technology

2008-06-13

thrust stand [rad/s] I. Introduction A capillary discharge based coaxial , electrothermal pulsed plasma thruster (PPT) is currently under...20-23 July 2008. 14. ABSTRACT A capillary discharge based pulsed plasma thruster is currently under development at the Air Force Research...Edwards AFB, CA 93524 A capillary discharge based pulsed plasma thruster is currently under development at the Air Force Research Laboratory. A

Discharge Against Medical Advice in the Pediatric Wards in Boo-ali Sina Hospital, Sari, Iran 2010.

PubMed

Mohseni Saravi, Benyamin; Reza Zadeh, Esmaeil; Siamian, Hasan; Yahghoobian, Mahboobeh

2013-12-01

Since children neither comprehended nor contribute to the decision, discharge against medical advice is a challenge of health care systems in the world. Therefore, the current study was designed to determine the rate and causes of discharge against medical advice. This descriptive cross-sectional study was done by reviewing the medical records by census method. Data was analyzed using SPSS software and x(2) statistics was used to determine the relationship between variables. The value of P<0.05 was considered significant. Rate of discharged against medical advice was 108 (2.2%). Mean of age and length of stay were 2.8±4 (SD).3 years old and 3.7±5.4 (SD) days, respectively. Totally, 95 patients (88.7%) had health insurance and 65 (60.2%) patients lived in urban areas. History of psychiatric disease and addiction in 22 (20.6%) of the parents were negative. In addition, 100 (92.3%) patients admitted for medical treatment and the others for surgery. The relationship of the signatory with patients (72.3%) was father. Of 108 patients discharged against medical advice, 20 (12%) were readmitted. The relationship between the day of discharge and discharge against medical advice was significant (ρ =0/03). Rate of discharge against medical advice in Boo-ali hospital is the same as the other studies in the same range. The form which is used for this purpose did not have suitable data elements about description of consequence of such discharge, and it has not shown the real causes of discharge against medical advice.

Response of nickel to zinc cells to electric vehicle chopper discharge waveforms

NASA Technical Reports Server (NTRS)

Cataldo, R. L.

1981-01-01

The preliminary results of simulated electric vehicle chopper controlled discharge of a Nickel/Zinc battery shows delivered energy increases of 5 to 25 percent compared to constant current discharges of the same average current. The percentage increase was a function of chopper frequency, the ratio of peak to average current, and the magnitude of the discharge current. Because the chopper effects are of a complex nature, electric vehicle battery/speed controller interaction must be carefully considered in vehicle design to optimize battery performance.

Post-Discharge Care Duration, Charges, and Outcomes Among Medicare Patients After Primary Total Hip and Knee Arthroplasty.

PubMed

Ponnusamy, Karthikeyan E; Naseer, Zan; El Dafrawy, Mostafa H; Okafor, Louis; Alexander, Clayton; Sterling, Robert S; Khanuja, Harpal S; Skolasky, Richard L

2017-06-07

In April 2016, the U.S. Centers for Medicare & Medicaid Services initiated mandatory 90-day bundled payments for total hip and knee arthroplasty for much of the country. Our goal was to determine duration of care, 90-day charges, and readmission rates by discharge disposition and U.S. region after hip or knee arthroplasty. Using the 2008 Medicare Provider Analysis and Review database 100% sample, we identified patients who had undergone elective primary total hip or knee arthroplasty. We collected data on patient age, sex, comorbidities, U.S. Census region, discharge disposition, duration of care, 90-day charges, and readmission. Multivariate regression was used to assess factors associated with readmission (logistic) and charges (linear). Significance was set at p < 0.01. Patients undergoing 138,842 total hip arthroplasties were discharged to home (18%), home health care (34%), extended-care facilities (35%), and inpatient rehabilitation (13%); patients undergoing 329,233 total knee arthroplasties were discharged to home (21%), home health care (38%), extended-care facilities (31%), and inpatient rehabilitation (10%). Patients in the Northeast were more likely to be discharged to extended-care facilities or inpatient rehabilitation than patients in other regions. Patients in the West had the highest 90-day charges. Approximately 70% of patients were discharged home from extended-care facilities, whereas after inpatient rehabilitation, >50% of patients received home health care. Among those discharged to home, 90-day readmission rates were highest in the South (9.6%) for patients undergoing total hip arthroplasty and in the Midwest (8.7%) and the South (8.5%) for patients undergoing total knee arthroplasty. Having ≥4 comorbidities, followed by discharge to inpatient rehabilitation or an extended-care facility, had the strongest associations with readmission, whereas the region of the West and the discharge disposition to inpatient rehabilitation had the strongest association with higher charges. Among Medicare patients, discharge disposition and number of comorbidities were most strongly associated with readmission. Inpatient rehabilitation and the West region had the strongest associations with higher charges. Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Discharge mode transition and temporal-spatial evolution of an air-water plasma jet generated by pulsating DC power

NASA Astrophysics Data System (ADS)

Lei, J.; Geng, Y.; Liu, K.; Zhu, W.; Zheng, Z.; Hu, H.

2017-12-01

In this paper, pulsating direct current air-water plasma jet, which can increase the production of •OH and decrease the temperature, is studied. The results show that the discharge mode changes in one cycle from corona discharge with steep Trichel current pulse to glow-like discharge. It is unknown whether the different discharge modes and water ratio have an effect on the transient process of the excited O and •OH production and the mechanism of plasma propagation. So, a series of experiments are done in this paper. The results show that the changing rules of both the excited state O and the discharge current reach their two peak values synchronously. And its maximum appears at the time of the first peak current value in corona mode. However, the change of the excited state •OH is different. It increases to its maximum at the time of the second peak current value in glow-like mode. Besides, the intensified charge coupled device photographs show that the luminous intensity of the discharge zone at the first peak current value in corona mode is stronger than the second peak current value in glow-like mode. At the same time, the discharge area of the former is larger than the latter. Nevertheless, with the increase in water ratio, the discharge area change reversed. Additionally, the air plasma plume propagation depends on the gas flow. The initial propagation velocity decreases with the increase in water ratio.

Simplified Numerical Description of SPT Operations

NASA Technical Reports Server (NTRS)

Manzella, David H.

1995-01-01

A simplified numerical model of the plasma discharge within the SPT-100 stationary plasma thruster was developed to aid in understanding thruster operation. A one dimensional description was used. Non-axial velocities were neglected except for the azimuthal electron velocity. A nominal operating condition of 4.5 mg/s of xenon anode flow was considered with 4.5 Amperes of discharge current, and a peak radial magnetic field strength of 130 Gauss. For these conditions, the calculated results indicated ionization fractions of 0.99 near the thruster exit with a potential drop across the discharge of approximately 250 Volts. Peak calculated electron temperatures were found to be sensitive to the choice of total ionization cross section for ionization of atomic xenon by electron bombardment and ranged from 51 eV to 60 eV. The calculated ionization fraction, potential drop, and electron number density agree favorably with previous experiments. Calculated electron temperatures are higher than previously measured.

Evaluation of Fatigue Behavior and Surface Characteristics of Aluminum Alloy 2024 T6 After Electric Discharge Machining

NASA Astrophysics Data System (ADS)

Mehmood, Shahid; Shah, Masood; Pasha, Riffat Asim; Sultan, Amir

2017-10-01

The effect of electric discharge machining (EDM) on surface quality and consequently on the fatigue performance of Al 2024 T6 is investigated. Five levels of discharge current are analyzed, while all other electrical and nonelectrical parameters are kept constant. At each discharge current level, dog-bone specimens are machined by generating a peripheral notch at the center. The fatigue tests are performed on four-point rotating bending machine at room temperature. For comparison purposes, fatigue tests are also performed on the conventionally machined specimens. Linearized SN curves for 95% failure probability and with four different confidence levels (75, 90, 95 and 99%) are plotted for each discharge current level as well as for conventionally machined specimens. These plots show that the electric discharge machined (EDMed) specimens give inferior fatigue behavior as compared to conventionally machined specimen. Moreover, discharge current inversely affects the fatigue life, and this influence is highly pronounced at lower stresses. The EDMed surfaces are characterized by surface properties that could be responsible for change in fatigue life such as surface morphology, surface roughness, white layer thickness, microhardness and residual stresses. It is found that all these surface properties are affected by changing discharge current level. However, change in fatigue life by discharge current could not be associated independently to any single surface property.

Optical emission spectroscopy of point-plane corona and back-corona discharges in air

NASA Astrophysics Data System (ADS)

Czech, T.; Sobczyk, A. T.; Jaworek, A.

2011-12-01

Results of spectroscopic investigations and current-voltage characteristics of corona discharge and back discharge on fly-ash layer, generated in point-plane electrode geometry in air at atmospheric pressure are presented in the paper. The characteristics of both discharges are similar but differ in the current and voltage ranges of all the discharge forms distinguished during the experiments. Three forms of back discharge, for positive and negative polarity, were investigated: glow, streamer and low-current back-arc. In order to characterize ionisation and excitation processes in back discharge, the emission spectra were measured and compared with those obtained for normal corona discharge generated in the same electrode configuration but with fly ash layer removed. The emission spectra were measured in two discharge zones: near the tip of needle electrode and near the plate. Visual forms of the discharge were recorded with digital camera and referred to current-voltage characteristics and emission spectra. The measurements have shown that spectral lines emitted by back discharge depend on the form of discharge and the discharge current. From the comparison of the spectral lines of back and normal discharges an effect of fly ash layer on the discharge morphology can be determined. The recorded emission spectra formed by ionised gas and plasma near the needle electrode and fly ash layer are different. It should be noted that in back arc emission, spectral lines of fly ash layer components can be distinguished. On the other hand, in needle zone, the emission of high intensity N2 second positive system and NO γ lines can be noticed. Regardless of these gaseous lines, also atomic lines of dust layer were present in the spectrum. The differences in spectra of back discharge for positive and negative polarities of the needle electrode have been explained by considering the kind of ions generated in the crater in fly ash layer. The aim of these studies is to better understand the discharge processes encountered in electrostatic precipitators.

Smoking-Cessation Interventions for Urban Hospital Patients: A Randomized Comparative Effectiveness Trial.

PubMed

Sherman, Scott E; Link, Alissa R; Rogers, Erin S; Krebs, Paul; Ladapo, Joseph A; Shelley, Donna R; Fang, Yixin; Wang, Binhuan; Grossman, Ellie

2016-10-01

Hospitalization is a unique opportunity for smoking cessation, but prior interventions have measured efficacy with narrowly defined populations. The objective of this study was to enroll smokers admitted to two "safety net" hospitals and compare the effectiveness of two post-discharge cessation interventions. A randomized comparative effectiveness trial was conducted. At two New York City public hospitals, every hospitalized patient identified as a smoker (based on admission records) was approached. Inclusion criteria were: smoked cigarettes in the past 30 days; spoke English, Spanish, or Mandarin; had a U.S. phone number; not discharged to an institution where follow-up or smoking was limited; and not pregnant/breastfeeding. Of 18,797 patients identified as current smokers between July 2011 and April 2014, a total of 3,047 (16%) were discharged before being approached, 3,273 (17%) were not current smokers, 4,026 (21%) had no U.S. phone number, 2,831 (15%) were ineligible for other reasons, and 3,983 (21%) refused participation. In total, 1,618 (9%) participants enrolled in the study. During follow-up, 69% of participants were reached at 2 months and 68% at 6 months. At discharge, participants were randomized to multisession telephone counseling from study staff (n=804) or referral to the state quitline for proactive outreach and counseling (n=814). Self-reported abstinence at 6 months was measured. Analyses were conducted in late 2015. One quarter of participants were homeless or in unstable housing, 60% had a history of substance abuse, 43% reported current hazardous drinking, and half had a psychiatric diagnosis other than substance abuse. At follow-up, the rate of abstinence (30-day point prevalence) was higher in the intensive counseling arm than the quitline arm at 2 months (29.0% vs 20.7%; relative risk=1.40; 95% CI=1.13, 1.73) and 6 months (37.4% vs 31.5%; relative risk=1.19; 95% CI=1.01, 1.40). Intensive counseling was more effective than referral to the state quitline. Long-term abstinence was excellent in both groups. Many patients were not eligible for enrollment despite minimal exclusion criteria. This study is registered at www.clinicaltrials.gov NCT01363245. Published by Elsevier Inc.

[Relationships between pollutants discharge and red tide occurrence in Shenzhen eastern coast].

PubMed

Jiang, Tian-jiu; Niu, Tao; Ying, Wen-ye

2007-05-01

The study on the effects of pollutants discharge on red tide occurrence in eastern sea area of Shenzhen showed that the occurrence frequency of dinoflagellate red tide had significant positive correlations with the net discharge of total nitrogen (TN) and total phosphorous (TP) as well as the N/P ratio of the discharge. The thresholds of net discharged TN and TP were estimated to be 3.917 x 10(3) t and 2.123 x 10(4) t, respectively. No significant correlation was observed between diatom red tide and alongshore pollutants discharge. An example was given to illustrate the means of pollutants discharge control.

Modelling of the EAST lower-hybrid current drive experiment using GENRAY/CQL3D and TORLH/CQL3D

NASA Astrophysics Data System (ADS)

Yang, C.; Bonoli, P. T.; Wright, J. C.; Ding, B. J.; Parker, R.; Shiraiwa, S.; Li, M. H.

2014-12-01

The coupled GENRAY-CQL3D code has been used to do systematic ray-tracing and Fokker-Planck analysis for EAST Lower Hybrid wave Current Drive (LHCD) experiments. Despite being in the weak absorption regime, the experimental level of LH current drive is successfully simulated, by taking into account the variations in the parallel wavenumber due to the toroidal effect. The effect of radial transport of the fast LH electrons in EAST has also been studied, which shows that a modest amount of radial transport diffusion can redistribute the fast LH current significantly. Taking advantage of the new capability in GENRAY, the actual Scrape Off Layer (SOL) model with magnetic field, density, temperature, and geometry is included in the simulation for both the lower and the higher density cases, so that the collisional losses of Lower Hybrid Wave (LHW) power in the SOL has been accounted for, which together with fast electron losses can reproduce the LHCD experimental observations in different discharges of EAST. We have also analyzed EAST discharges where there is a significant ohmic contribution to the total current, and good agreement with experiment in terms of total current has been obtained. Also, the full-wave code TORLH has been used for the simulation of the LH physics in the EAST, including full-wave effects such as diffraction and focusing which may also play an important role in bridging the spectral gap. The comparisons between the GENRAY and the TORLH codes are done for both the Maxwellian and the quasi-linear electron Landau damping cases. These simulations represent an important addition to the validation studies of the GENRAY-CQL3D and TORLH models being used in weak absorption scenarios of tokamaks with large aspect ratio.

Physical mechanisms of self-organization and formation of current patterns in gas discharges of the Townsend and glow types

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

Raizer, Yu. P.; Mokrov, M. S.

The paper discusses current filamentation and formation of current structures (in particular, hexagonal current patterns) in discharges of the Townsend and glow types. The aim of the paper, which is in part a review, is to reveal basic reasons for formation of current patterns in different cases, namely, in dielectric barrier discharge, discharge with semiconductor cathode, and micro-discharge between metallic electrodes. Pursuing this goal, we give a very brief review of observations and discuss only those theoretical, computational, and experimental papers that shed light on the physical mechanisms involved. The mechanisms are under weak currents—the thermal expansion of the gasmore » as a result of Joule heating; under enhanced currents—the electric field and ionization rate redistribution induced by space charge. Both mechanisms lead to instability of the homogeneous discharges. In addition, we present new results of numerical simulations of observed short-living current filaments which are chaotic in space and time.« less

Current Risk Adjustment and Comorbidity Index Underperformance in Predicting Post-Acute Utilization and Hospital Readmissions After Joint Replacements: Implications for Comprehensive Care for Joint Replacement Model.

PubMed

Kumar, Amit; Karmarkar, Amol; Downer, Brian; Vashist, Amit; Adhikari, Deepak; Al Snih, Soham; Ottenbacher, Kenneth

2017-11-01

To compare the performances of 3 comorbidity indices, the Charlson Comorbidity Index, the Elixhauser Comorbidity Index, and the Centers for Medicare & Medicaid Services (CMS) risk adjustment model, Hierarchical Condition Category (HCC), in predicting post-acute discharge settings and hospital readmission for patients after joint replacement. A retrospective study of Medicare beneficiaries with total knee replacement (TKR) or total hip replacement (THR) discharged from hospitals in 2009-2011 (n = 607,349) was performed. Study outcomes were post-acute discharge setting and unplanned 30-, 60-, and 90-day hospital readmissions. Logistic regression models were built to compare the performance of the 3 comorbidity indices using C statistics. The base model included patient demographics and hospital use. Subsequent models included 1 of the 3 comorbidity indices. Additional multivariable logistic regression models were built to identify individual comorbid conditions associated with high risk of hospital readmissions. The 30-, 60-, and 90-day unplanned hospital readmission rates were 5.3%, 7.2%, and 8.5%, respectively. Patients were most frequently discharged to home health (46.3%), followed by skilled nursing facility (40.9%) and inpatient rehabilitation facility (12.7%). The C statistics for the base model in predicting post-acute discharge setting and 30-, 60-, and 90-day readmission in TKR and THR were between 0.63 and 0.67. Adding the Charlson Comorbidity Index, the Elixhauser Comorbidity Index, or HCC increased the C statistic minimally from the base model for predicting both discharge settings and hospital readmission. The health conditions most frequently associated with hospital readmission were diabetes mellitus, pulmonary disease, arrhythmias, and heart disease. The comorbidity indices and CMS-HCC demonstrated weak discriminatory ability to predict post-acute discharge settings and hospital readmission following joint replacement. © 2017, American College of Rheumatology.

Characteristics of back corona discharge in a honeycomb catalyst and its application for treatment of volatile organic compounds.

PubMed

Feng, Fada; Zheng, Yanyan; Shen, Xinjun; Zheng, Qinzhen; Dai, Shaolong; Zhang, Xuming; Huang, Yifan; Liu, Zhen; Yan, Keping

2015-06-02

The main technical challenges for the treatment of volatile organic compounds (VOCs) with plasma-assisted catalysis in industrial applications are large volume plasma generation under atmospheric pressure, byproduct control, and aerosol collection. To solve these problems, a back corona discharge (BCD) configuration has been designed to evenly generate nonthermal plasma in a honeycomb catalyst. Voltage-current curves, discharge images, and emission spectra have been used to characterize the plasma. Grade particle collection results and flow field visualization in the discharge zones show not only that the particles can be collected efficiently, but also that the pressure drop of the catalyst layer is relatively low. A three-stage plasma-assisted catalysis system, comprising a dielectric barrier discharge (DBD) stage, BCD stage, and catalyst stage, was built to evaluate toluene treatment performance by BCD. The ozone analysis results indicate that BCD enhances the ozone decomposition by collecting aerosols and protecting the Ag-Mn-O catalyst downstream from aerosol contamination. The GC and FTIR results show that BCD contributes to toluene removal, especially when the specific energy input is low, and the total removal efficiency reaches almost 100%. Furthermore, this removal results in the emission of fewer byproducts.

Narrow band vacuum ultraviolet radiation, produced by fast conical discharge

NASA Astrophysics Data System (ADS)

Antsiferov, P. S.; Dorokhin, L. A.; Koshelev, K. N.

2018-04-01

The article presents the experimental study of discharges in a conical cavity, filled with Ar at pressure 80 Pa. The electrical current driver (inductive storage with plasma erosion opening switch) supplies to the load electrical current pulse with growth rate about 1012 A s‑1 and maximal value 30–40 kA. The convergent conical shock wave starts from the inner surface of the discharge cavity and collapses in ‘zippering’ mode. The pin hole camera imaging with MCP detector (time resolution 5 ns) have demonstrated the appearance of effectively fast moving compact plasma with visible velocity v  =  (1.5  ±  0.14)  ×  107 cm s‑1. Plasma emits narrow band radiation in the spectral range of Rydberg series transitions of Ar VII, Ar VIII with quantum number up to n  =  9 (wavelength about 11 nm). The intensity of radiation is comparable with the total plasma emission in the range 10–50 nm. Charge exchange between multiply charged Ar ions and cold Ar atoms of working gas is proposed as the possible mechanism of the origin of the radiation.

Thyroid gland removal - discharge

MedlinePlus

... tingling in your face or lips Alternative Names Total thyroidectomy - discharge; Partial thyroidectomy - discharge; Thyroidectomy - discharge; Subtotal thyroidectomy - discharge References Lai SY, Mandel SJ, Weber RS. Management of thyroid neoplasms. In: Flint PW, Haughey BH, ...

Chopper-controlled discharge life cycling studies on lead-acid batteries

NASA Technical Reports Server (NTRS)

Kraml, J. J.; Ames, E. P.

1982-01-01

State-of-the-art 6 volt lead-acid golf car batteries were tested. A daily charge/discharge cycling to failure points under various chopper controlled pulsed dc and continuous current load conditions was undertaken. The cycle life and failure modes were investigated for depth of discharge, average current chopper frequency, and chopper duty cycle. It is shown that battery life is primarily and inversely related to depth of discharge and discharge current. Failure mode is characterized by a gradual capacity loss with consistent evidence of cell element aging.

Response of lead-acid batteries to chopper-controlled discharge: Preliminary results

NASA Technical Reports Server (NTRS)

Cataldo, R. L.

1978-01-01

The preliminary results of simulated electric vehicle, chopper, speed controller discharge of a battery show energy output losses up to 25 percent compared to constant current discharges at the same average discharge current of 100 amperes. These energy losses are manifested as temperature rises during discharge, amounting to a two-fold increase for a 400-ampere pulse compared to the constant current case. Because of the potentially large energy inefficiency, the results suggest that electric vehicle battery/speed controller interaction must be carefully considered in vehicle design.

Response of lead-acid batteries to chopper-controlled discharge

NASA Technical Reports Server (NTRS)

Cataldo, R. L.

1978-01-01

The preliminary results of simulated electric vehicle, chopper, speed controller discharge of a battery show energy output losses at up to 25 percent compared to constant current discharges at the same average discharge current of 100 A. These energy losses are manifested as temperature rises during discharge, amounting to a two-fold increase for a 400-A pulse compared to the constant current case. Because of the potentially large energy inefficiency, the results suggest that electric vehicle battery/speed controller interaction must be carefully considered in vehicle design.

Parental language and dosing errors after discharge from the pediatric emergency department.

PubMed

Samuels-Kalow, Margaret E; Stack, Anne M; Porter, Stephen C

2013-09-01

Safe and effective care after discharge requires parental education in the pediatric emergency department (ED). Parent-provider communication may be more difficult with parents who have limited health literacy or English-language fluency. This study examined the relationship between language and discharge comprehension regarding medication dosing. We completed a prospective observational study of the ED discharge process using a convenience sample of English- and Spanish-speaking parents of children 2 to 24 months presenting to a single tertiary care pediatric ED with fever and/or respiratory illness. A bilingual research assistant interviewed parents to ascertain their primary language and health literacy and observed the discharge process. The primary outcome was parental demonstration of an incorrect dose of acetaminophen for the weight of his or her child. A total of 259 parent-child dyads were screened. There were 210 potential discharges, and 145 (69%) of 210 completed the postdischarge interview. Forty-six parents (32%) had an acetaminophen dosing error. Spanish-speaking parents were significantly more likely to have a dosing error (odds ratio, 3.7; 95% confidence interval, 1.6-8.1), even after adjustment for language of discharge, income, and parental health literacy (adjusted odds ratio, 6.7; 95% confidence interval, 1.4-31.7). Current ED discharge communication results in a significant disparity between English- and Spanish-speaking parents' comprehension of a crucial aspect of medication safety. These differences were not explained purely by interpretation, suggesting that interventions to improve comprehension must address factors beyond language alone.

Methods for accurate estimation of net discharge in a tidal channel

USGS Publications Warehouse

Simpson, M.R.; Bland, R.

2000-01-01

Accurate estimates of net residual discharge in tidally affected rivers and estuaries are possible because of recently developed ultrasonic discharge measurement techniques. Previous discharge estimates using conventional mechanical current meters and methods based on stage/discharge relations or water slope measurements often yielded errors that were as great as or greater than the computed residual discharge. Ultrasonic measurement methods consist of: 1) the use of ultrasonic instruments for the measurement of a representative 'index' velocity used for in situ estimation of mean water velocity and 2) the use of the acoustic Doppler current discharge measurement system to calibrate the index velocity measurement data. Methods used to calibrate (rate) the index velocity to the channel velocity measured using the Acoustic Doppler Current Profiler are the most critical factors affecting the accuracy of net discharge estimation. The index velocity first must be related to mean channel velocity and then used to calculate instantaneous channel discharge. Finally, discharge is low-pass filtered to remove the effects of the tides. An ultrasonic velocity meter discharge-measurement site in a tidally affected region of the Sacramento-San Joaquin Rivers was used to study the accuracy of the index velocity calibration procedure. Calibration data consisting of ultrasonic velocity meter index velocity and concurrent acoustic Doppler discharge measurement data were collected during three time periods. Two sets of data were collected during a spring tide (monthly maximum tidal current) and one of data collected during a neap tide (monthly minimum tidal current). The relative magnitude of instrumental errors, acoustic Doppler discharge measurement errors, and calibration errors were evaluated. Calibration error was found to be the most significant source of error in estimating net discharge. Using a comprehensive calibration method, net discharge estimates developed from the three sets of calibration data differed by less than an average of 4 cubic meters per second, or less than 0.5% of a typical peak tidal discharge rate of 750 cubic meters per second.

Simplified methods for computing total sediment discharge with the modified Einstein procedure

USGS Publications Warehouse

Colby, Bruce R.; Hubbell, David Wellington

1961-01-01

A procedure was presented in 1950 by H. A. Einstein for computing the total discharge of sediment particles of sizes that are in appreciable quantities in the stream bed. This procedure was modified by the U.S. Geological Survey and adapted to computing the total sediment discharge of a stream on the basis of samples of bed sediment, depth-integrated samples of suspended sediment, streamflow measurements, and water temperature. This paper gives simplified methods for computing total sediment discharge by the modified Einstein procedure. Each of four homographs appreciably simplifies a major step in the computations. Within the stated limitations, use of the homographs introduces much less error than is present in either the basic data or the theories on which the computations of total sediment discharge are based. The results are nearly as accurate mathematically as those that could be obtained from the longer and more complex arithmetic and algebraic computations of the Einstein procedure.

Characterization of Downstream Ion Energy Distributions From a High Current Hollow Cathode in a Ring Cusp Discharge Chamber

NASA Technical Reports Server (NTRS)

Foster, John E.; Patterson, Michael J.

2003-01-01

The presence of energetic ions produced by a hollow cathodes operating at high emission currents (greater than 10 Angstroms) has been documented in the literature. As part of an ongoing effort to uncover the underlying physics of the formation of these ions, ion efflux from a high current hollow cathode operating in an ion thruster discharge chamber was investigated. Using a spherical sector electrostatic energy analyzer located downstream of the discharge cathode, the ion energy distribution over a 0 to 60 eV energy range was measured. The sensitivity of the ion energy distribution function to zenith angle was also assessed at 3 different positions: 0, 15, and 25 degrees. The measurements suggest that the majority of the ion current at the measuring point falls into the analyzer with an energy approximately equal to the discharge voltage. The ion distribution, however, was found to be quite broad. The high energy tail of the distribution function tended to grow with increasing discharge current. Sensitivity of the profiles to flow rate at fixed discharge current was also investigated. A simple model is presented that provides a potential mechanism for the production of ions with energies above the discharge voltage.

The evolution of discharge current and channel radius in cloud-to-ground lightning return stroke process

NASA Astrophysics Data System (ADS)

Fan, Tingting; Yuan, Ping; Wang, Xuejuan; Cen, Jianyong; Chang, Xuan; Zhao, Yanyan

2017-09-01

The spectra of two negative cloud-to-ground lightning discharge processes with multi-return strokes are obtained by a slit-less high-speed spectrograph, which the temporal resolution is 110 μs. Combined with the synchronous electrical observation data and theoretical calculation, the physical characteristics during return strokes process are analysed. A positive correlation between discharge current and intensity of ionic lines in the spectra is verified, and based on this feature, the current evolution characteristics during four return strokes are investigated. The results show that the time from peak current to the half-peak value estimated by multi point-fitting is about 101 μs-139 μs. The Joule heat in per unit length of four return strokes channel is in the order of 105J/m-106 J/m. The radius of arc discharge channel is positively related to the discharge current, and the more intense the current is, the greater the radius of channel is. Furthermore, the evolution for radius of arc core channel in the process of return stroke is consistent with the change trend of discharge current after the peak value. Compared with the decay of the current, the temperature decreases more slowly.

Generation of a pulsed low-energy electron beam using the channel spark device

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

Elgarhy, M. A. I., E-mail: elgarhy@azhar.edu.eg; Hassaballa, S. E.; Rashed, U. M.

2015-12-15

For the generation of low-energy electron beam, the design and characteristics of channel spark discharge (CSD) operating at a low voltage are presented in this paper. The discharge voltage, discharge current, X-ray emissions, and electron beam current were experimentally determined. The effects of the applied voltage, working gas pressure, and external capacitance on the CSD and beam parameters were measured. At an applied voltage of 11 kV, an oxygen gas pressure of 25 mTorr, and an external capacitance of 16.45 nF, the maximum measured current was 900 A. The discharge current increased with the increase in the pressure and capacitance,more » while its periodic time decreased with the increase in the pressure. Two types of the discharge were identified and recorded: the hollow cathode discharge and the conduction discharge. A Faraday cup was used to measure the beam current. The maximum measured beam current was 120 A, and the beam signal exhibited two peaks. The increase in both the external capacitance and the applied discharge voltage increased the maximum electron beam current. The electron-beam pulse time decreased with the increase in the gas pressure at a constant voltage and increased with the decrease in the applied discharge voltage. At an applied voltage of 11 kV and an oxygen gas pressure of 15 mTorr, the maximum beam energy was 2.8 keV. The X-ray signal intensity decreased with the increase in the gas pressure and increased with the increase in the capacitance.« less

Remote Estimation of River Discharge and Bathymetry: Sensitivity to Turbulent Dissipation and Bottom Friction

NASA Astrophysics Data System (ADS)

Simeonov, J.; Holland, K. T.

2016-12-01

We investigated the fidelity of a hierarchy of inverse models that estimate river bathymetry and discharge using measurements of surface currents and water surface elevation. Our most comprehensive depth inversion was based on the Shiono and Knight (1991) model that considers the depth-averaged along-channel momentum balance between the downstream pressure gradient due to gravity, the bottom drag and the lateral stresses induced by turbulence. The discharge was determined by minimizing the difference between the predicted and the measured streamwise variation of the total head. The bottom friction coefficient was assumed to be known or determined by alternative means. We also considered simplifications of the comprehensive inversion model that exclude the lateral mixing term from the momentum balance and assessed the effect of neglecting this term on the depth and discharge estimates for idealized in-bank flow in symmetric trapezoidal channels with width/depth ratio of 40 and different side-wall slopes. For these simple gravity-friction models, we used two different bottom friction parameterizations - a constant Darcy-Weisbach local friction and a depth-dependent friction related to the local depth and a constant Manning (roughness) coefficient. Our results indicated that the Manning gravity-friction model provides accurate estimates of the depth and the discharge that are within 1% of the assumed values for channels with side-wall slopes between 1/2 and 1/17. On the other hand, the constant Darcy-Weisbach friction model underpredicted the true depth and discharge by 7% and 9%, respectively, for the channel with side-wall slope of 1/17. These idealized modeling results suggest that a depth-dependent parameterization of the bottom friction is important for accurate inversion of depth and discharge and that the lateral turbulent mixing is not important. We also tested the comprehensive and the simplified inversion models for the Kootenai River near Bonners Ferry (Idaho) using in situ and remote sensing measurements of surface currents and water surface elevation obtained during a 2010 field experiment.

High current plasma electron emitter

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

Fiksel, G.; Almagri, A.F.; Craig, D.

1995-07-01

A high current plasma electron emitter based on a miniature plasma source has been developed. The emitting plasma is created by a pulsed high current gas discharge. The electron emission current is 1 kA at 300 V at the pulse duration of 10 ms. The prototype injector described in this paper will be used for a 20 kA electrostatic current injection experiment in the Madison Symmetric Torus (MST) reversed-field pinch. The source will be replicated in order to attain this total current requirement. The source has a simple design and has proven very reliable in operation. A high emission current,more » small size (3.7 cm in diameter), and low impurity generation make the source suitable for a variety of fusion and technological applications.« less

40 CFR 63.623 - Standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... discharged into the atmosphere from any affected source any gases which contain total fluorides in excess of... shall cause to be discharged into the atmosphere from any affected source any gases which contain total... this subpart shall cause to be discharged into the atmosphere from any affected source any gases which...

40 CFR 63.623 - Standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... discharged into the atmosphere from any affected source any gases which contain total fluorides in excess of... shall cause to be discharged into the atmosphere from any affected source any gases which contain total... this subpart shall cause to be discharged into the atmosphere from any affected source any gases which...

40 CFR 63.622 - Standards for existing sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... discharged into the atmosphere from any affected source any gases which contain total fluorides in excess of... shall cause to be discharged into the atmosphere from any affected source any gases which contain total... this subpart shall cause to be discharged into the atmosphere from any affected source any gases which...

40 CFR 63.623 - Standards for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... discharged into the atmosphere from any affected source any gases which contain total fluorides in excess of... shall cause to be discharged into the atmosphere from any affected source any gases which contain total... this subpart shall cause to be discharged into the atmosphere from any affected source any gases which...

40 CFR 63.622 - Standards for existing sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... discharged into the atmosphere from any affected source any gases which contain total fluorides in excess of... shall cause to be discharged into the atmosphere from any affected source any gases which contain total... this subpart shall cause to be discharged into the atmosphere from any affected source any gases which...

40 CFR 63.622 - Standards for existing sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... discharged into the atmosphere from any affected source any gases which contain total fluorides in excess of... shall cause to be discharged into the atmosphere from any affected source any gases which contain total... this subpart shall cause to be discharged into the atmosphere from any affected source any gases which...

40 CFR 63.623 - Standards for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... discharged into the atmosphere from any affected source any gases which contain total fluorides in excess of... shall cause to be discharged into the atmosphere from any affected source any gases which contain total... this subpart shall cause to be discharged into the atmosphere from any affected source any gases which...

40 CFR 63.622 - Standards for existing sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... discharged into the atmosphere from any affected source any gases which contain total fluorides in excess of... shall cause to be discharged into the atmosphere from any affected source any gases which contain total... this subpart shall cause to be discharged into the atmosphere from any affected source any gases which...

40 CFR 63.623 - Standards for new sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... discharged into the atmosphere from any affected source any gases which contain total fluorides in excess of... shall cause to be discharged into the atmosphere from any affected source any gases which contain total... this subpart shall cause to be discharged into the atmosphere from any affected source any gases which...

40 CFR 63.622 - Standards for existing sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... discharged into the atmosphere from any affected source any gases which contain total fluorides in excess of... shall cause to be discharged into the atmosphere from any affected source any gases which contain total... this subpart shall cause to be discharged into the atmosphere from any affected source any gases which...

Hydrothermal heat discharge in the Cascade Range, northwestern United States

USGS Publications Warehouse

Ingebritsen, S.E.; Mariner, R.H.

2010-01-01

Hydrothermal heat discharge in the Cascade Range includes the heat discharged by thermal springs, by "slightly thermal" springs that are only a few degrees warmer than ambient temperature, and by fumaroles. Thermal-spring heat discharge is calculated on the basis of chloride-flux measurements and geothermometer temperatures and totals ~ 240 MW in the U.S. part of the Cascade Range, excluding the transient post-1980 discharge at Mount St. Helens (~80 MW as of 2004-5). Heat discharge from "slightly thermal" springs is based on the degree of geothermal warming (after correction for gravitational potential energy effects) and totals ~. 660. MW. Fumarolic heat discharge is calculated by a variety of indirect and direct methods and totals ~160 MW, excluding the transient mid-1970s discharge at Mount Baker (~80 MW) and transient post-1980 discharge at Mount St. Helens (>. 230. MW as of 2005). Other than the pronounced transients at Mount St. Helens and Mount Baker, hydrothermal heat discharge in the Cascade Range appears to be fairly steady over a ~25-year period of measurement. Of the total of ~. 1050. MW of "steady" hydrothermal heat discharge identified in the U.S. part of the Cascade Range, less than 50. MW occurs north of latitude 45??15' N (~0.1 MW per km arc length from 45??15' to 49??N). Much greater rates of hydrothermal heat discharge south of 45??15'N (~1.7 MW per km arc length from 40?? to 45??15'N) may reflect the influence of Basin and Range-style extensional tectonics (faulting) that impinges on the Cascades as far north as Mount Jefferson but is not evident farther north. ?? 2010.

Ion extraction capabilities of two-grid accelerator systems. [for spacecraft propulsion

NASA Technical Reports Server (NTRS)

Rovang, D. C.; Wilbur, P. J.

1984-01-01

An experimental investigation into the ion extraction capabilities of two-grid accelerator systems common to electrostatic ion thrusters is described. A large body of experimental data which facilitates the selection of the accelerator system geometries and operating parameters necessary to maximize the extracted ion current is presented. Results suggest that the impingement-limited perveance is not dramatically affected by reductions in screen hole diameter to 0.5 mm. Impingement-limited performance is shown to depend most strongly on grid separation distance, accelerator hole diameter ratio, the discharge-to-total accelerating voltage ratio, and the net-to-total accelerating voltage ratio. Results obtained at small grid separation ratios suggest a new grid operating condition where high beam current per hole levels are achieved at a specified net accelerating voltage. It is shown that this operating condition is realized at an optimum ratio of net-to-total accelerating voltage ratio which is typically quite high.

Ion extraction capabilities of closely spaced grids

NASA Technical Reports Server (NTRS)

Rovang, D. C.; Wilbur, P. J.

1982-01-01

The ion extraction capabilities of accelerator systems with small screen hole diameters (less than 2.0 mm) are investigated at net-accelerating voltages of 100, 300, and 500 V. Results show that the impingement-limited perveance is not dramatically affected by reductions in screen hole diameter to 1.0 mm, but impingement-limited performance was found to be dependent on the grid separation distance, the discharge-to-total accelerating voltage ratio, and the net-to-total accelerating voltage ratio. Results obtained using small hole diameters and closely spaced grids indicate a new mode of grid operation where high current density operation can be achieved with a specified net acceleration voltage by operating the grids at a high rather than low net-to-total acceleration voltage. Beam current densities as high as 25 mA/sq cm were obtained using grids with 1.0 mm diameter holes operating at a net accelerating voltage of 500 V.

Performance of a High-Fidelity 4kW-Class Engineering Model PPU and Integration with HiVHAc System

NASA Technical Reports Server (NTRS)

Pinero, Luis R.; Kamhawi, Hani; Shilo, Vladislav

2016-01-01

The High Voltage Hall Accelerator (HiVHAc) propulsion system consists of a thruster,power processing unit (PPU), and propellant feed system. An engineering model PPU was developed by Colorado Power Electronics, Inc. funded by NASA's Small Business Innovative Research Program. This PPU uses an innovative 3-phase resonant converter to deliver 4 kW of discharge power over a wide range of input and output voltage conditions.The PPU includes a digital control interface unit that automatically controls the PPU and a xenon flow control module (XFCM). It interfaces with a control computer to receive high level commands and relay telemetry through a MIL-STD-1553B interface. The EM PPU was thoroughly tested at GRC for functionality and performance at temperature extremes and demonstrated total efficiencies a high as 95 percent. It was integrated with the HiVHAc thruster and the XFCM to demonstrate closed-loop control of discharge current with anode flow. Initiation of the main discharge and power throttling were also successfully demonstrated and discharge oscillations were characterized.

Performance of a High-Fidelity 4kW-Class Engineering Model PPU and Integration with HiVHAc System

NASA Technical Reports Server (NTRS)

Pinero, Luis R.; Kamhawi, Hani; Shilo, Vlad

2016-01-01

The High Voltage Hall Accelerator (HiVHAc) propulsion system consists of a thruster, power processing unit (PPU), and propellant feed system. An engineering model PPU was developed by Colorado Power Electronics, Inc. funded by NASA's Small Business Innovative Research Program. This PPU uses an innovative 3-phase resonant converter to deliver 4 kW of discharge power over a wide range of input and output voltage conditions. The PPU includes a digital control interface unit that automatically controls the PPU and a xenon flow control module (XFCM). It interfaces with a control computer to receive highlevel commands and relay telemetry through a MIL-STD-1553B interface. The EM PPU was thoroughly tested at GRC for functionality and performance at temperature limits and demonstrated total efficiencies a high as 95 percent. Integrated testing of the unit was performed with the HiVHAc thruster and the XFCM to demonstrate closed-loop control of discharge current with anode flow. Initiation of the main discharge and power throttling were also successfully demonstrated and discharge oscillations were characterized.

Acoustic Doppler discharge-measurement system

USGS Publications Warehouse

Simpson, Michael R.; Oltmann, Richard N.; ,

1990-01-01

A discharge-measurement system that uses a vessel-mounted acoustic Doppler current profiler has been developed and tested by the U.S. Geological Survey. Discharge measurements using the system require a fraction of the time needed for conventional current-meter discharge measurements and do not require shore-based navigational aids or tag lines for positioning the vessel.

Static current-voltage characteristics for radio-frequency induction discharge

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

Budyansky, A.; Zykov, A.

1995-12-31

The aim of this work was to obtain experimentally such characteristic of Radio-Frequency Induction Discharge (RFID) that can play the role of its current-voltage characteristic (CVC) and to explain the nature of current and voltage jumps arising in RF coils at exciting of discharge. Experiments were made in quartz 5.5, 11, 20 cm diam tubes with outer RF coil at pressures 10--100 mTorr, at frequency 13.56 MHz and discharge power to 500 W. In case of outer coil as analogue of discharge voltage it`s convenient to use the value of the RF voltage U{sub R}, induced around outer perimeter ofmore » discharge tube. It is evident that current and voltage jumps arising at exciting of discharge are due to low output resistance of standard generators and negative slope of initial part of CVC. Three sets of such dependencies for different pressures were obtained for each diameter of tubes. The influence of different metal electrodes placed into discharge volume on CVC`s shape has been studied also. Experimental results can explain the behavior of HFI discharge as a load of RF generator and give data for calculation of RF circuit.« less

A randomised controlled trial evaluating a rehabilitation complex intervention for patients following intensive care discharge: the RECOVER study

PubMed Central

Salisbury, Lisa G; Boyd, Julia; Ramsay, Pamela; Merriweather, Judith; Huby, Guro; Forbes, John; Rattray, Janice Z; Griffith, David M; Mackenzie, Simon J; Hull, Alastair; Lewis, Steff; Murray, Gordon D

2012-01-01

Introduction Patients who survive an intensive care unit admission frequently suffer physical and psychological morbidity for many months after discharge. Current rehabilitation pathways are often fragmented and little is known about the optimum method of promoting recovery. Many patients suffer reduced quality of life. Methods and analysis The authors plan a multicentre randomised parallel group complex intervention trial with concealment of group allocation from outcome assessors. Patients who required more than 48 h of mechanical ventilation and are deemed fit for intensive care unit discharge will be eligible. Patients with primary neurological diagnoses will be excluded. Participants will be randomised into one of the two groups: the intervention group will receive standard ward-based care delivered by the NHS service with additional treatment by a specifically trained generic rehabilitation assistant during ward stay and via telephone contact after hospital discharge and the control group will receive standard ward-based care delivered by the current NHS service. The intervention group will also receive additional information about their critical illness and access to a critical care physician. The total duration of the intervention will be from randomisation to 3 months postrandomisation. The total duration of follow-up will be 12 months from randomisation for both groups. The primary outcome will be the Rivermead Mobility Index at 3 months. Secondary outcomes will include measures of physical and psychological morbidity and function, quality of life and survival over a 12-month period. A health economic evaluation will also be undertaken. Groups will be compared in relation to primary and secondary outcomes; quantitative analyses will be supplemented by focus groups with patients, carers and healthcare workers. Ethics and dissemination Consent will be obtained from patients and relatives according to patient capacity. Data will be analysed according to a predefined analysis plan. Trial registration The trial is registered as ISRCTN09412438 and funded by the Chief Scientist Office, Scotland. PMID:22761291

Water table management reduces tile nitrate loss in continuous corn and in a soybean-corn rotation.

PubMed

Drury, C F; Tan, C S; Gaynor, J D; Reynolds, W D; Welacky, T W; Oloya, T O

2001-10-25

Water table management systems can be designed to alleviate soil water excesses and deficits, as well as reduce nitrate leaching losses in tile discharge. With this in mind, a standard tile drainage (DR) system was compared over 8 years (1991 to 1999) to a controlled tile drainage/subirrigation (CDS) system on a low-slope (0.05 to 0.1%) Brookston clay loam soil (Typic Argiaquoll) in southwestern Ontario, Canada. In the CDS system, tile discharge was controlled to prevent excessive drainage, and water was pumped back up the tile lines (subirrigation) to replenish the crop root zone during water deficit periods. In the first phase of the study (1991 to 1994), continuous corn (Zea mays, L.) was grown with annual nitrogen (N) fertilizer inputs as per local soil test recommendations. In the second phase (1995 to 1999), a soybean (Glycine max L., Merr.)-corn rotation was used with N fertilizer added only during the two corn years. In Phase 1 when continuous corn was grown, CDS reduced total tile discharge by 26% and total nitrate loss in tile discharge by 55%, compared to DR. In addition, the 4-year flow weighted mean (FWM) nitrate concentration in tile discharge exceeded the Canadian drinking water guideline (10 mg N l(-1)) under DR (11.4 mg N l(-1)), but not under CDS (7.0 mg N l(-1)). In Phase 2 during the soybean-corn rotation, CDS reduced total tile discharge by 38% and total nitrate loss in tile discharge by 66%, relative to DR. The 4-year FWM nitrate concentration during Phase 2 in tile discharge was below the drinking water guideline for both DR (7.3 mg N l(-1)) and CDS (4.0 mg N l(-1)). During both phases of the experiment, the CDS treatment caused only minor increases in nitrate loss in surface runoff relative to DR. Hence CDS decreased FWM nitrate concentrations, total drainage water loss, and total nitrate loss in tile discharge relative to DR. In addition, soybean-corn rotation reduced FWM nitrate concentrations and total nitrate loss in tile discharge relative to continuous corn. CDS and crop rotations with reduced N fertilizer inputs can thus improve the quality of tile discharge water substantially.

Spatial Characteristics and Driving Factors of Provincial Wastewater Discharge in China.

PubMed

Chen, Kunlun; Liu, Xiaoqiong; Ding, Lei; Huang, Gengzhi; Li, Zhigang

2016-12-09

Based on the increasing pressure on the water environment, this study aims to clarify the overall status of wastewater discharge in China, including the spatio-temporal distribution characteristics of wastewater discharge and its driving factors, so as to provide reference for developing "emission reduction" strategies in China and discuss regional sustainable development and resources environment policies. We utilized the Exploratory Spatial Data Analysis (ESDA) method to analyze the characteristics of the spatio-temporal distribution of the total wastewater discharge among 31 provinces in China from 2002 to 2013. Then, we discussed about the driving factors, affected the wastewater discharge through the Logarithmic Mean Divisia Index (LMDI) method and classified those driving factors. Results indicate that: (1) the total wastewater discharge steadily increased, based on the social economic development, with an average growth rate of 5.3% per year; the domestic wastewater discharge is the main source of total wastewater discharge, and the amount of domestic wastewater discharge is larger than the industrial wastewater discharge. There are many spatial differences of wastewater discharge among provinces via the ESDA method. For example, provinces with high wastewater discharge are mainly the developed coastal provinces such as Jiangsu Province and Guangdong Province. Provinces and their surrounding areas with low wastewater discharge are mainly the undeveloped ones in Northwest China; (2) The dominant factors affecting wastewater discharge are the economy and technological advance; The secondary one is the efficiency of resource utilization, which brings about the unstable effect; population plays a less important role in wastewater discharge. The dominant driving factors affecting wastewater discharge among 31 provinces are divided into three types, including two-factor dominant type, three-factor leading type and four-factor antagonistic type. In addition, the proposals aimed at reducing the wastewater discharge are provided on the basis of these three types.

34 CFR 685.213 - Total and permanent disability discharge.

Code of Federal Regulations, 2013 CFR

2013-07-01

... application for discharge. To qualify for a discharge of a Direct Loan based on a total and permanent... award. The application must contain— (i) A certification by a physician, who is a doctor of medicine or... evidence if the Secretary determines that the borrower's application does not conclusively prove that the...

34 CFR 685.213 - Total and permanent disability discharge.

Code of Federal Regulations, 2014 CFR

2014-07-01

... application for discharge. To qualify for a discharge of a Direct Loan based on a total and permanent... award. The application must contain— (i) A certification by a physician, who is a doctor of medicine or... evidence if the Secretary determines that the borrower's application does not conclusively prove that the...

Initiation of long, free-standing z discharges by CO2 laser gas heating

NASA Astrophysics Data System (ADS)

Niemann, C.; Tauschwitz, A.; Penache, D.; Neff, S.; Knobloch, R.; Birkner, R.; Presura, R.; Hoffmann, D. H. H.; Yu, S. S.; Sharp, W. M.

2002-01-01

High current discharge channels can neutralize both current and space charge of very intense ion beams. Therefore, they are considered an interesting solution for final focus and beam transport in a heavy ion beam fusion reactor. At the Gesellschaft für Schwerionenforschung accelerator facility, 50 cm long, free-standing discharge channels were created in a 60 cm diameter metallic chamber. Discharges with currents of 45 kA in 2 to 25 mbar ammonia (NH3) gas are initiated by a CO2 laser pulse along the channel axis before the capacitor bank is triggered. Resonant absorption of the laser, tuned to the v2 vibration of the ammonia molecule, causes strong gas heating. Subsequent expansion and rarefaction of the gas prepare the conditions for a stable discharge to fulfill the requirements for ion beam transport. The influence of an electric prepulse on the high current discharge was investigated. This article describes the laser-gas interaction and the discharge initiation mechanism. We found that channels are magnetohydrodynamic stable up to currents of 45 kA, measured by fast shutter and streak imaging techniques. The rarefaction of the laser heated gas is studied by means of a one-dimensional Lagrangian fluid code (CYCLOPS) and is identified as the dominant initiation mechanism of the discharge.

Sustained diffusive alternating current gliding arc discharge in atmospheric pressure air

NASA Astrophysics Data System (ADS)

Zhu, Jiajian; Gao, Jinlong; Li, Zhongshan; Ehn, Andreas; Aldén, Marcus; Larsson, Anders; Kusano, Yukihiro

2014-12-01

Rapid transition from glow discharge to thermal arc has been a common problem in generating stable high-power non-thermal plasmas especially at ambient conditions. A sustained diffusive gliding arc discharge was generated in a large volume in atmospheric pressure air, driven by an alternating current (AC) power source. The plasma column extended beyond the water-cooled stainless steel electrodes and was stabilized by matching the flow speed of the turbulent air jet with the rated output power. Comprehensive investigations were performed using high-speed movies measured over the plasma column, synchronized with simultaneously recorded current and voltage waveforms. Dynamic details of the novel non-equilibrium discharge are revealed, which is characterized by a sinusoidal current waveform with amplitude stabilized at around 200 mA intermediate between thermal arc and glow discharge, shedding light to the governing mechanism of the sustained spark-suppressed AC gliding arc discharge.

Real-world costs of ischemic stroke by discharge status.

PubMed

Mu, F; Hurley, D; Betts, K A; Messali, A J; Paschoalin, M; Kelley, C; Wu, E Q

2017-02-01

The objective of this study was to estimate the acute healthcare costs of ischemic stroke during hospitalization and the quarterly all-cause healthcare costs for the first year after discharge by discharge status. Adult patients with a hospitalization with a diagnosis of ischemic stroke (ICD-9-CM: 434.xx or 436.xx) between 1 January 2006 and 31 March 2015 were identified from a large US commercial claims database. Patients were classified into three cohorts based on their discharge status from the first stroke hospitalization, i.e. dead at discharge, discharged with disability, or discharged without disability. Third-party (medical and pharmacy) and out-of-pocket costs were adjusted to 2015 USD. A total of 7919 patients dead at discharge, 45,695 patients discharged with disability, and 153,778 patients discharged without disability were included in this analysis. The overall average age was 59.7 years and 52.3% were male. During hospitalization, mean total costs (third-party and out-of-pocket) were $68,370 for patients dead at discharge, $73,903 for patients discharged with disability, and $24,448 for patients discharged without disability (p < .001 for each pairwise comparison); mean third-party costs were $63,605 for patients dead at discharge, $67,861 for patients discharged with disability and $19,267 for patients discharged without disability (p < .001 for each pairwise comparison). During the first year after discharge, mean total costs for patients discharged with disability vs. without disability were $46,850 vs. $30,132 (p < .001). Mean third-party costs for patients discharged with disability vs. without disability were $19,116 vs. $10,976 during the first quarter after discharge, $10,236 vs. $6926 during the second quarter, $8241 vs. $5810 during the third quarter, and $6875 vs. $5292 during the fourth quarter (p < .001 for each quarter). The results demonstrated the high economic burden of ischemic stroke, especially among patients discharged with disability with the highest costs incurred during the inpatient stays.

Characterization of electrical discharges on Teflon dielectrics used as spacecraft thermal control

NASA Technical Reports Server (NTRS)

Yadlowsky, E. J.; Hazelton, R. C.; Churchill, R. J.

1979-01-01

The dual effects of system degradation and reduced life of synchronous-orbit satellites as a result of differential spacecraft charging underscore the need for a clearer understanding of the prevailing electrical discharge phenomena. In a laboratory simulation, the electrical discharge current, surface voltage, emitted particle fluxes, and photo-emission associated with discharge events on electron beam irradiated silver-backed Teflon samples were measured. Sample surface damage was examined with optical and electron beam microscopes. The results are suggestive of a model in which the entire sample surface is discharged by lateral sub-surface currents flowing from a charge deposition layer through a localized discharge channel to the back surface of the sample. The associated return current pulse appears to have a duration which may be a signature by which different discharge processes may be characterized.

Evaluation of acoustic doppler velocity meters to quantify flow from Comal Springs and San Marcos Springs, Texas

USGS Publications Warehouse

Gary, Marcus O.; Gary, Robin H.; Asquith, William H.

2008-01-01

Comal Springs and San Marcos Springs are the two largest springs in Texas, are major discharge points for the San Antonio segment of the Edwards aquifer, and provide habitat for several Federally listed endangered species that depend on adequate springflows for survival. It is therefore imperative that the Edwards Aquifer Authority have accurate and timely springflow data to guide resource management. Discharge points for Comal Springs and San Marcos Springs are submerged in Landa Lake and in Spring Lake, respectively. Flows from the springs currently (2008) are estimated by the U.S Geological Survey in real time as surface-water discharge from conventional stage-discharge ratings at sites downstream from each spring. Recent technological advances and availability of acoustic Doppler velocity meters (ADVMs) now provide tools to collect data (stream velocity) related to springflow that could increase accuracy of real-time estimates of the springflows. The U.S. Geological Survey, in cooperation with the Edwards Aquifer Authority, did a study during May 2006 through September 2007 to evaluate ADVMs to quantify flow from Comal and San Marcos Springs. The evaluation was based on two monitoring approaches: (1) placement of ADVMs in important spring orifices - spring run 3 and spring 7 at Comal Springs, and diversion spring at San Marcos Springs; and (2) placement of ADVMs at the nearest flowing streams - Comal River new and old channels for Comal Springs, Spring Lake west and east outflow channels and current (2008) San Marcos River streamflow-gaging site for San Marcos Springs. For Comal Springs, ADVM application at spring run 3 and spring 7 was intended to indicate whether the flows of spring run 3 and spring 7 can be related to total springflow. The findings indicate that velocity data from both discharge features, while reflecting changes in flow, do not reliably show a direct relation to measured streamflow and thus to total Comal Springs flow. ADVMs at the Comal River new channel and old channel sites provide data that potentially could yield more accurate real-time estimates of total Comal Springs flow than streamflow measured at the downstream Comal River site. For San Marcos Springs, the findings indicate shortcomings with ADVM installations at diversion spring and in the west and east outflow channels. However, the accuracy of streamflow measured at the San Marcos River gage as an estimate of real-time San Marcos Springs flow could potentially be increased through use of ADVM data from that site.

Modelling of the reactive sputtering process with non-uniform discharge current density and different temperature conditions

NASA Astrophysics Data System (ADS)

Vašina, P; Hytková, T; Eliáš, M

2009-05-01

The majority of current models of the reactive magnetron sputtering assume a uniform shape of the discharge current density and the same temperature near the target and the substrate. However, in the real experimental set-up, the presence of the magnetic field causes high density plasma to form in front of the cathode in the shape of a toroid. Consequently, the discharge current density is laterally non-uniform. In addition to this, the heating of the background gas by sputtered particles, which is usually referred to as the gas rarefaction, plays an important role. This paper presents an extended model of the reactive magnetron sputtering that assumes the non-uniform discharge current density and which accommodates the gas rarefaction effect. It is devoted mainly to the study of the behaviour of the reactive sputtering rather that to the prediction of the coating properties. Outputs of this model are compared with those that assume uniform discharge current density and uniform temperature profile in the deposition chamber. Particular attention is paid to the modelling of the radial variation of the target composition near transitions from the metallic to the compound mode and vice versa. A study of the target utilization in the metallic and compound mode is performed for two different discharge current density profiles corresponding to typical two pole and multipole magnetics available on the market now. Different shapes of the discharge current density were tested. Finally, hysteresis curves are plotted for various temperature conditions in the reactor.

Computations of total sediment discharge, Niobrara River near Cody, Nebraska

USGS Publications Warehouse

Colby, Bruce R.; Hembree, C.H.

1955-01-01

A natural chute in the Niobrara River near Cody, Nebr., constricts the flow of the river except at high stages to a narrow channel in which the turbulence is sufficient to suspend nearly the total sediment discharge. Because much of the flow originates in the sandhills area of Nebraska, the water discharge and sediment discharge are relatively uniform. Sediment discharges based on depth-integrated samples at a contracted section in the chute and on streamflow records at a recording gage about 1,900 feet upstream are available for the period from April 1948 to September 1953 but are not given directly as continuous records in this report. Sediment measurements have been made periodically near the gage and at other nearby relatively unconfined sections of the stream for comparison with measurements at the contracted section. Sediment discharge at these relatively unconfined sections was computed from formulas for comparison with measured sediment discharges at the contracted section. A form of the Du Boys formula gave computed tonnages of sediment that were unsatisfactory. Sediment discharges as computed from the Schoklitsch formula agreed well with measured sediment discharges that were low, but they were much too low at measured sediment discharges that were higher. The Straub formula gave computed discharges, presumably of bed material, that were several times larger than measured discharges of sediment coarser than 0.125 millimeter. All three of these formulas gave computed sediment discharges that increased with water discharges much less rapidly than the measured discharges of sediment coarser than 0.125 millimeter. The Einstein procedure when applied to a reach that included 10 defined cross sections gave much better agreement between computed sediment discharge and measured sediment discharge than did anyone of the three other formulas that were used. This procedure does not compute the discharge of sediment that is too small to be found in the stream bed in appreciable quantities. Hence, total sediment discharges were obtained by adding computed discharges of sediment larger than 0.125 millimeter to measured discharges of sediment smaller than 0.125 millimeter. The size distributions of the computed sediment discharge compared poorly with the size distributions of sediment discharge at the contracted section. Ten sediment discharges computed from the Einstein procedure as applied to a single section averaged several times the measured sediment discharge for the contracted section and gave size distributions that were unsatisfactory. The Einstein procedure was modified to compute total sediment discharge at an alluvial section from readily measurable field data. The modified procedure uses measurements of bed-material particle sizes, suspended-sediment concentrations and particle sizes from depth-integrated samples, streamflow, and water temperatures. Computations of total sediment discharge were made by using this modified procedure, some for the section at the gaging station and some for each of two other relatively unconfined sections. The size distributions of the computed and the measured sediment discharges agreed reasonably well. Major advantages of this modified procedure include applicability to a single section rather than to a reach of channel, use of measured velocity instead of water-surface slope, use of depth-integrated samples, and apparently fair accuracy for computing both total sediment discharge and approximate size distribution of the sediment. Because of these advantages this modified procedure is being further studied to increase its accuracy, to simplify the required computations, and to define its limitations. In the development of the modified procedure, some relationships concerning theories of sediment transport were reviewed and checked against field data. Vertical distributions of suspended sediment at relatively unconfined sections did not agree well with theoretical dist

The utility of the FIM+FAM for assessing traumatic brain injury day program outcomes.

PubMed

Seel, Ronald T; Wright, Greg; Wallace, Tracey; Newman, Sary; Dennis, Leanne

2007-01-01

To evaluate the effectiveness of the FIM+FAM as a primary outcome measure for traumatic brain injury (TBI) comprehensive day programs. Retrospective data analysis. Single center, TBI comprehensive day program facility. A demographically and regionally diverse sample of 105 persons with moderate or severe TBI admitted to the Shepherd Pathways comprehensive TBI day rehabilitation program. Functional Independence Measure + Functional Assessment Measure (FIM+FAM). Twenty-eight percent or fewer of participants reached ceiling effects on 25 of the 30 FIM+FAM items at day program admission with only 2% of clients rated above ceiling score levels on the FIM+FAM total score. The criteria of Guyatt et al showed that 20 of the 30 FIM+FAM items showed clinically meaningful improvements in 60% or more of clients. On average, clients with TBI improved over 27 points on the FIM+FAM total score. Fifteen of 30 items showed ceiling effects of 33% or less at discharge where only 25% of clients exceeded the FIM+FAM total score ceiling threshold. Discharge FIM+FAM motor scale was a very good predictor of the need for additional single service physical therapy. However, reaching ceiling rating on the FIM+FAM cognitive scale demonstrated poor specificity (0.28) and negative predictive power (0.42) for the need for additional speech/cognitive therapy services. The FIM+FAM demonstrated utility as an outcome measure for TBI comprehensive day program treatment in the current milieu. Future research is required to replicate and extend the current findings.

Hydrograph Predictions of Glacial Lake Outburst Floods From an Ice-Dammed Lake

NASA Astrophysics Data System (ADS)

McCoy, S. W.; Jacquet, J.; McGrath, D.; Koschitzki, R.; Okuinghttons, J.

2017-12-01

Understanding the time evolution of glacial lake outburst floods (GLOFs), and ultimately predicting peak discharge, is crucial to mitigating the impacts of GLOFs on downstream communities and understanding concomitant surface change. The dearth of in situ measurements taken during GLOFs has left many GLOF models currently in use untested. Here we present a dataset of 13 GLOFs from Lago Cachet Dos, Aysen Region, Chile in which we detail measurements of key environmental variables (total volume drained, lake temperature, and lake inflow rate) and high temporal resolution discharge measurements at the source lake, in addition to well-constrained ice thickness and bedrock topography. Using this dataset we test two common empirical equations as well as the physically-based model of Spring-Hutter-Clarke. We find that the commonly used empirical relationships based solely on a dataset of lake volume drained fail to predict the large variability in observed peak discharges from Lago Cachet Dos. This disagreement is likely because these equations do not consider additional environmental variables that we show also control peak discharge, primarily, lake water temperature and the rate of meltwater inflow to the source lake. We find that the Spring-Hutter-Clarke model can accurately simulate the exponentially rising hydrographs that are characteristic of ice-dammed GLOFs, as well as the order of magnitude variation in peak discharge between events if the hydraulic roughness parameter is allowed to be a free fitting parameter. However, the Spring-Hutter-Clarke model over predicts peak discharge in all cases by 10 to 35%. The systematic over prediction of peak discharge by the model is related to its abrupt flood termination that misses the observed steep falling limb of the flood hydrograph. Although satisfactory model fits are produced, the range in hydraulic roughness required to obtain these fits across all events was large, which suggests that current models do not completely capture the physics of these systems, thus limiting their ability to truly predict peak discharges using only independently constrained parameters. We suggest what some of these missing physics might be.

Aetiological agents of ear discharge: a two year review in a teaching hospital in Ghana.

PubMed

Appiah-Korang, L; Asare-Gyasi, S; Yawson, A E; Searyoh, K

2014-06-01

The discharging ear is a common presentation in medical practice affecting all age groups but primarily children. This study shows the current aetiological causes of ear discharge and their antibiograms, data which would guide empirical treatment of ear infections, and also form a basis for further research. This was a retrospective review of laboratory records of all ear swabs submitted for culture over a two year period in the Korle Bu Teaching Hospital Accra, Ghana. Data was obtained on demographic characteristics of patients, clinical diagnosis, isolated organisms and antibiotic susceptibility patterns of the isolated organisms. Data was analyzed by simple descriptive statistics. A total of 351 ear swabs were received by the laboratory for processing over the two year period. Of these 277(78.9%) had microorganisms isolated. A significant number127 (47%) was obtained from children under five years. Pseudomonas spp was the commonly isolated organism 121(46%) followed by Staphylococcus aureus 33(12.5%) and Proteus spp 32(12.2%). Candida was the commonest isolated fungi 9 (69.2%). Susceptibility of Pseudomonas spp to commonly used ototopics (ciprofloxacin & gentamicin) was 93% and 74% respectively. Most cases of the discharging ear were found in children under the age of five years. The most common bacteriologic cause of the discharging ear was Pseudomonas spp followed by Staphylococcus aureus. Candida species was the commonest fungal cause of ear discharge. Ciprofloxacin and gentamicin are effective ototopic antimicrobial agents for empirical treatment of the discharging ear.

Electrical and optical characteristics of atmospheric pressure plasma needle jet driven by neon trasformer

NASA Astrophysics Data System (ADS)

Elfa, Rizan Rizon; Ahmad, Mohd Khairul; Soon, Chin Fhong; Sahdan, Mohd Zainizan; Lias, Jais; Mamat, Mohamad Hafiz; Rusop, Mohamad; Nayan, Nafarizal

2017-09-01

The atmospheric pressure plasma needle jet driven by double sinusoidal waveform of neon transformer is reported in this paper. The commercial neon transformer produces about 5 kV of peak sinusoidal voltages and 35 kHz of frequency. Argon gas has been used as discharge gas for this system since the discharge was easily developed rather than using helium gas. In addition, argon gas is three times cheaper than helium gas. The electrical property of the argon discharge has been analyzed in details by measuring its voltage, current and power during the discharge process. Interestingly, it has been found that the total power on the inner needle electrode was slightly lower than that of outer electrode. This may be due to the polarization charges that occurred at inner needle electrode. Then, further investigation to understand the discharge properties was carried out using optical emission spectroscopy (OES) analysis. During OES measurements, two positions of plasma discharge are measured by aligning the quartz optical lens and spectrometer fiber. The OH emission intensity was found higher than that of N2 at the plasma orifice. However, OH emission intensity was lower at 1.5 cm distance from orifice which may be due to penning ionization effect. These results and understanding are essential for surface modification and biomedical applications of atmospheric pressure plasma needle jet.

Effect of a direct current bias on the electrohydrodynamic performance of a surface dielectric barrier discharge actuator for airflow control

NASA Astrophysics Data System (ADS)

Yan, Huijie; Yang, Liang; Qi, Xiaohua; Ren, Chunsheng

2015-02-01

The effect of a DC bias on the electrohydrodynamics (EHD) force induced by a surface dielectric barrier AC discharge actuator for airflow control at the atmospheric pressure is investigated. The measurement of the surface potential due to charge deposition at different DC biases is carried out by using a special designed corona like discharge potential probe. From the surface potential data, the plasma electromotive force is shown not affected much by the DC biases except for some reduction of the DC bias near the exposed electrode edge for the sheath-like configuration. The total thrust is measured by an analytical balance, and an almost linear relationship to the potential voltage at the exposed electrode edge is found for the direct thrust force. The temporally averaged ionic wind characteristics are investigated by Pitot tube sensor and schlieren visualization system. It is found that the ionic wind velocity profiles with different DC biases are almost the same in the AC discharge plasma area but gradually diversified in the further downstream area as well as the upper space away from the discharge plasma area. Also, the DC bias can significantly modify the topology of the ionic wind produced by the AC discharge actuator. These results can provide an insight into how the DC biases to affect the force generation.

Ground level measurements of air conductivities under Florida thunderstorms

NASA Technical Reports Server (NTRS)

Blakeslee, Richard J.; Krider, E. P.

1992-01-01

Values of the positive and negative polar conductivities under summer thunderstorms in Florida are highly variable and exhibit a significant electrode effect, but the total conductivity usually remains close to values found in fair weather, 0.4 to 1.8 x 10 exp -14 S/m. With these values a method proposed by Krider and Musser (1982) for estimating the total conductivity from changes in the slope of the electric field recovery following a lightning discharge will be extremely sensitive to small time variations in the local Maxwell current density and must be modified to include these effects.

Fluid simulation of the bias effect in inductive/capacitive discharges

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

Zhang, Yu-Ru; Research Group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, Wilrijk, BE-2610 Antwerp; Gao, Fei

Computer simulations are performed for an argon inductively coupled plasma (ICP) with a capacitive radio-frequency bias power, to investigate the bias effect on the discharge mode transition and on the plasma characteristics at various ICP currents, bias voltages, and bias frequencies. When the bias frequency is fixed at 13.56 MHz and the ICP current is low, e.g., 6 A, the spatiotemporal averaged plasma density increases monotonically with bias voltage, and the bias effect is already prominent at a bias voltage of 90 V. The maximum of the ionization rate moves toward the bottom electrode, which indicates clearly the discharge mode transition in inductive/capacitivemore » discharges. At higher ICP currents, i.e., 11 and 13 A, the plasma density decreases first and then increases with bias voltage, due to the competing mechanisms between the ion acceleration power dissipation and the capacitive power deposition. At 11 A, the bias effect is still important, but it is noticeable only at higher bias voltages. At 13 A, the ionization rate is characterized by a maximum at the reactor center near the dielectric window at all selected bias voltages, which indicates that the ICP power, instead of the bias power, plays a dominant role under this condition, and no mode transition is observed. Indeed, the ratio of the bias power to the total power is lower than 0.4 over a wide range of bias voltages, i.e., 0–300 V. Besides the effect of ICP current, also the effect of various bias frequencies is investigated. It is found that the modulation of the bias power to the spatiotemporal distributions of the ionization rate at 2 MHz is strikingly different from the behavior observed at higher bias frequencies. Furthermore, the minimum of the plasma density appears at different bias voltages, i.e., 120 V at 2 MHz and 90 V at 27.12 MHz.« less

Nutrient input from the Loxahatchee River Environmental Control District sewage-treatment plant to the Loxahatchee River Estuary, southeastern Florida

USGS Publications Warehouse

Sonntag, W.H.; McPherson, B.F.

1984-01-01

Two test discharges of treated-sewage effluent were made to the Loxahatchee River in February and September 1981 from the ENCON sewage-treatment plant to document nutrient loading and downstream transport of the effluent to the estuary under maximum daily discharge allowable by law (4 million gallons per day). Concentrations of total nitrogen in the effluent exceeded background concentrations by as much as 7 times during the February test, while concentrations of total phosphorus exceeded background concentrations by as much as 112 times during the September test. The effluent was transported downstream to the estuary in less than 24 hours. Discharge of treated sewage effluent to the river-estuary system in the 1981 water year accounted for less than 0.5 percent of the total nitrogen and 8 percent of the total phosphorus discharged from the major tributaries to the estuary. If maximum discharges of effluent (4 million gallons per day) were sustained throughout the year, annual nitrogen loading from the effluent would account for 5 to 18 percent of the total nitrogen input by the major tributaries to the estuary. With maximum discharges of effluent, annual phosphorus loading would exceed the amount of phosphorus input by the major tributaries to the estuary by 54 to 167 percent. (USGS)

Prerequisites for Accurate Monitoring of River Discharge Based on Fixed-Location Velocity Measurements

NASA Astrophysics Data System (ADS)

Kästner, K.; Hoitink, A. J. F.; Torfs, P. J. J. F.; Vermeulen, B.; Ningsih, N. S.; Pramulya, M.

2018-02-01

River discharge has to be monitored reliably for effective water management. As river discharge cannot be measured directly, it is usually inferred from the water level. This practice is unreliable at places where the relation between water level and flow velocity is ambiguous. In such a case, the continuous measurement of the flow velocity can improve the discharge prediction. The emergence of horizontal acoustic Doppler current profilers (HADCPs) has made it possible to continuously measure the flow velocity. However, the profiling range of HADCPs is limited, so that a single instrument can only partially cover a wide cross section. The total discharge still has to be determined with a model. While the limitations of rating curves are well understood, there is not yet a comprehensive theory to assess the accuracy of discharge predicted from velocity measurements. Such a theory is necessary to discriminate which factors influence the measurements, and to improve instrument deployment as well as discharge prediction. This paper presents a generic method to assess the uncertainty of discharge predicted from range-limited velocity profiles. The theory shows that a major source of error is the variation of the ratio between the local and cross-section-averaged velocity. This variation is large near the banks, where HADCPs are usually deployed and can limit the advantage gained from the velocity measurement. We apply our theory at two gauging stations situated in the Kapuas River, Indonesia. We find that at one of the two stations the index velocity does not outperform a simple rating curve.

On the shape of the glow discharge channel

NASA Astrophysics Data System (ADS)

Dmitriev, A. L.; Nikushchenko, E. M.

2017-05-01

Examples of the shapes of the glow discharge channel are presented. The discharge has been initiated in air at a pressure of 0.1 atm. The effective value and frequency of the discharge current are 30-70 mA and 50 Hz, respectively. It has been shown that, for these values of the current and pressure, thermal convection in a vacuum chamber and buoyancy (Archimedes force) are not major reasons for the specific parabolic shape of glow discharge.

Discharge processes and an electrical model of atmospheric pressure plasma jets in argon

NASA Astrophysics Data System (ADS)

Fang, Zhi; Shao, Tao; Yang, Jing; Zhang, Cheng

2016-01-01

In this paper, an atmospheric pressure plasma discharge in argon was generated using a needle-to-ring electrode configuration driven by a sinusoidal excitation voltage. The electric discharge processes and discharge characteristics were investigated by inspecting the voltage-current waveforms, Lissajous curves and lighting emission images. The change in discharge mode with applied voltage amplitude was studied and characterised, and three modes of corona discharge, dielectric barrier discharge (DBD) and jet discharge were identified, which appeared in turn with increasing applied voltage and can be distinguished clearly from the measured voltage-current waveforms, light-emission images and the changing gradient of discharge power with applied voltage. Based on the experimental results and discharge mechanism analysis, an equivalent electrical model and the corresponding equivalent circuit for characterising the whole discharge processes accurately was proposed, and the three discharge stages were characterised separately. A voltage-controlled current source (VCCS) associated with a resistance and a capacitance were used to represent the DBD stage, and the plasma plume and corona discharge were modelled by a variable capacitor in series with a variable resistor. Other factors that can influence the discharge, such as lead and stray capacitance values of the circuit, were also considered in the proposed model. Contribution to the Topical Issue "Recent Breakthroughs in Microplasma Science and Technology", edited by Kurt Becker, Jose Lopez, David Staack, Klaus-Dieter Weltmann and Wei Dong Zhu.

Persistence of a Groundwater Contaminant Plume after Hydraulic Source Containment at a Chlorinated-Solvent Contaminated Site

PubMed Central

Matthieu, D.E.; Brusseau, M.L.; Guo, Z.; Plaschke, M.; Carroll, K.C.; Brinker, F.

2015-01-01

The objective of this study was to characterize the behavior of a groundwater contaminant (trichloroethene) plume after implementation of a source-containment operation at a site in Arizona. The plume resides in a quasi three-layer system comprising a sand/gravel unit bounded on the top and bottom by relatively thick silty clayey layers. The system was monitored for 60 months beginning at start-up in 2007 to measure the change in contaminant concentrations within the plume, the change in plume area, the mass of contaminant removed, and the integrated contaminant mass discharge. Concentrations of trichloroethene in groundwater pumped from the plume extraction wells have declined significantly over the course of operation, as have concentrations for groundwater sampled from 40 monitoring wells located within the plume. The total contaminant mass discharge associated with operation of the plume extraction wells peaked at 0.23 kg/d, decreased significantly within one year, and thereafter began an asymptotic decline to a current value of approximately 0.03 kg/d. Despite an 87% reduction in contaminant mass and a comparable 87% reduction in contaminant mass discharge for the plume, the spatial area encompassed by the plume has decreased by only approximately 50%. This is much less than would be anticipated based on ideal flushing and mass-removal behavior. Simulations produced with a simplified 3-D numerical model matched reasonably well to the measured data. The results of the study suggest that permeability heterogeneity, back diffusion, hydraulic factors associated with the specific well field system, and residual discharge from the source zone are all contributing to the observed persistence of the plume, as well as the asymptotic behavior currently observed for mass removal and for the reduction in contaminant mass discharge. PMID:26069436

Low-Carbon Watershed Management: Potential of Greenhouse Gas Reductions from Wastewater Treatment in Rural Vietnam.

PubMed

Nguyen, Lan Huong; Mohan, Geetha; Jian, Pu; Takemoto, Kazuhiko; Fukushi, Kensuke

2016-01-01

Currently in many cities and rural areas of Vietnam, wastewater is discharged to the environment without any treatment, which emits considerable amount of greenhouse gas (GHG), particularly methane. In this study, four GHG emission scenarios were examined, as well as the baseline scenario, in order to verify the potential of GHG reduction from domestic wastewater with adequate treatment facilities. The ArcGIS and ArcHydro tools were employed to visualize and analyze GHG emissions resulting from discharge of untreated wastewater, in rural areas of Vu Gia Thu Bon river basin, Vietnam. By applying the current IPCC guidelines for GHG emissions, we found that a reduction of GHG emissions can be achieved through treatment of domestic wastewater in the studied area. Compared with baseline scenario, a maximum 16% of total GHG emissions can be reduced, in which 30% of households existing latrines are substituted by Japanese Johkasou technology and other 20% of domestic wastewater is treated by conventional activated sludge.

The Elusive Evidence of Volcanic Lightning.

PubMed

Genareau, K; Gharghabi, P; Gafford, J; Mazzola, M

2017-11-14

Lightning strikes are known to morphologically alter and chemically reduce geologic formations and deposits, forming fulgurites. A similar process occurs as the result of volcanic lightning discharge, when airborne volcanic ash is transformed into lightning-induced volcanic spherules (LIVS). Here, we adapt the calculations used in previous studies of lightning-induced damage to infrastructure materials to determine the effects on pseudo-ash samples of simplified composition. Using laboratory high-current impulse experiments, this research shows that within the lightning discharge channel there is an ideal melting zone that represents roughly 10% or less of the total channel radius at which temperatures are sufficient to melt the ash, regardless of peak current. The melted ash is simultaneously expelled from the channel by the heated, expanding air, permitting particles to cool during atmospheric transport before coming to rest in ash fall deposits. The limited size of this ideal melting zone explains the low number of LIVS typically observed in volcanic ash despite the frequent occurrence of lightning during explosive eruptions.

In vitro antimicrobial effects and mechanisms of direct current air-liquid discharge plasma on planktonic Staphylococcus aureus and Escherichia coli in liquids.

PubMed

Xu, Zimu; Cheng, Cheng; Shen, Jie; Lan, Yan; Hu, Shuheng; Han, Wei; Chu, Paul K

2018-06-01

The direct inactivation effects of an atmospheric pressure direct current (DC) air plasma against planktonic Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in aqueous solution are investigated in vitro. Upon plasma treatment, extensively analyses on cell culturability, metabolic capacity, membrane integrity, surface morphology, cellular proteins, nucleic acids and intracellular reactive oxygen species (ROS) for both bacterial species were carried out and significant antimicrobial effects observed. Compared with the cellular culturability, a sub-lethal viable but non-culturable (VBNC) state was induced while more S. aureus entered this state than E. coli. Damaged bacterial outer structures were observed and the total concentrations of cellular protein and nucleic acid decreased for both bacteria after plasma treatment. The plasma-induced aqueous reactive species (RS) and intracellular ROS might produce detrimental effects to the bacteria, while S. aureus was less susceptible to the discharge after a 20-min exposure compared to E. coli. Copyright © 2018 Elsevier B.V. All rights reserved.

Low-Carbon Watershed Management: Potential of Greenhouse Gas Reductions from Wastewater Treatment in Rural Vietnam

PubMed Central

Mohan, Geetha; Jian, Pu; Takemoto, Kazuhiko; Fukushi, Kensuke

2016-01-01

Currently in many cities and rural areas of Vietnam, wastewater is discharged to the environment without any treatment, which emits considerable amount of greenhouse gas (GHG), particularly methane. In this study, four GHG emission scenarios were examined, as well as the baseline scenario, in order to verify the potential of GHG reduction from domestic wastewater with adequate treatment facilities. The ArcGIS and ArcHydro tools were employed to visualize and analyze GHG emissions resulting from discharge of untreated wastewater, in rural areas of Vu Gia Thu Bon river basin, Vietnam. By applying the current IPCC guidelines for GHG emissions, we found that a reduction of GHG emissions can be achieved through treatment of domestic wastewater in the studied area. Compared with baseline scenario, a maximum 16% of total GHG emissions can be reduced, in which 30% of households existing latrines are substituted by Japanese Johkasou technology and other 20% of domestic wastewater is treated by conventional activated sludge. PMID:27699202

Production of atmospheric-pressure glow discharge in nitrogen using needle-array electrode

NASA Astrophysics Data System (ADS)

Takaki, K.; Hosokawa, M.; Sasaki, T.; Mukaigawa, S.; Fujiwara, T.

2005-04-01

An atmospheric pressure glow discharge was generated using a needle-array electrode in nitrogen, and the voltage-current characteristics of the glow discharge were obtained in a range from 1 mA to 60 A. A pulsed high voltage with short rise time under 10 ns was employed to generate streamer discharges simultaneously at all needle tips. The large number of streamer discharges prevented the glow-to-arc transition caused by inhomogeneous thermalization. Semiconductor opening switch diodes were employed as an opening switch to shorten the rise time. The glow voltage was almost constant until the discharge current became 0.3 A, whereas the voltage increased with the current higher than 0.3 A. Electron density and temperature in a positive column of the glow discharge at 60 A were obtained to 1.4×1012cm-3 and 1.3 eV from calculation based on nitrogen swarm data.

An audit of adherence to heart failure guidelines in an Australian hospital: A pharmacist perspective.

PubMed

Khalil, Viviane; Danninger, Melanie; Wang, Wei; Khalil, Hanan

2017-12-01

The Australian National Heart Foundation Guidelines have been developed to guide clinicians on how to best manage chronic heart failure (CHF) patients according to the current best available evidence. The primary aim of this study is to evaluate the proportion of patients prescribed evidence-based therapy (EBT) for CHF on discharge at this Australian metropolitan hospital and factors affecting its prescribing. The secondary aims are to examine the proportion of patients prescribed EBT on discharge on cardiac wards compared to medical wards and to explore the role of the pharmacist in the management of these patients. A retrospective audit of patients' medical notes who were admitted consecutively for CHF management was conducted over 6 months to examine their management. The results showed at discharge, a total of 52% of patients were discharged on angiotensin converting enzyme inhibitors/angiotensin receptor blockers, 49% were discharged on β-blockers, 15% were on Aldosterone receptor antagonists, 90% were discharged on diuretics, and 29% were discharged on Digoxin. The main determinants of prescribing EBT on discharge were the presence of prescribing contraindications and patients' comorbidities. Patients discharged from cardiac wards were more likely to be prescribed EBT than if discharged on medical wards. Furthermore, in the subset of the cohort who was reviewed by a pharmacist during admission, a higher percentage of patients were discharged on EBT compared with those who did not have a pharmaceutical input. This study highlighted existing gaps between the National CHF Guidelines and clinical prescribing practice in this hospital. Patients who were discharged from cardiac wards were more likely to be prescribed medications concordant with the guidelines, and there is further opportunity for pharmacists to assist in closing gaps in prescribing practice by the promotion of adherence to these guidelines. © 2017 John Wiley & Sons, Ltd.

Experimental study of low-temperature plasma of electrical discharges with liquid electrodes

NASA Astrophysics Data System (ADS)

Zheltukhin, Viktor; Gaisin, Almaz

2016-09-01

Results of the experimental research of discharge between the liquid jet cathode (LJC) and the metal anode are presented. The discharge was studied over the voltage range U = 100 - 600 V, discharge current range I = 0 . 1 - 0 . 25 A, external pressure range P =105 Pa, discharge power Pd = 10 - 150 W. We used the techniques of infrared thermography and spectral measurements. Schlieren's photography is applied for describing the processes in liquid and gas phase. Results of the experimental researches of discharge current-voltage characteristic (CVC), the surface temperature distribution both on the LJC and the metal anode, a spectral measurements are showed. Effects of action both of breakdown and discharge on the jet flow as well as on the air flow near the discharge are described. It is found that the discharge CVC has an ascending behavior due to increase of plasma current density. The discharge is generated on the borders between the LJC and the metal anode as well as along the LJC misshaping this one. It is established that both the convection streams and an electrolyte drops are formed during the discharge burn. It is found that the discharge temperature in the vicinity of electrode surface reaches T 348 K. The work was funded by RFBR, according to the research projects No.,14-01-0755.

Observation and interpretation of energy efficient, diffuse direct current glow discharge at atmospheric pressure

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

Tang, Jie, E-mail: tangjie1979@opt.ac.cn; Jiang, Weiman; Wang, Yishan

2015-08-24

A diffuse direct-current glow discharge was realized with low energy consumption and high energy utilization efficiency at atmospheric pressure. The formation of diffuse discharge was demonstrated by examining and comparing the electrical properties and optical emissions of plasmas. In combination with theoretical derivation and calculation, we draw guidelines that appearance of nitrogen ions at low electron density is crucial to enhance the ambipolar diffusion for the expansion of discharge channel and the increasing ambipolar diffusion near the cathode plays a key role in the onset of diffuse discharge. An individual-discharge-channel expansion model is proposed to explain the diffuse discharge formation.

The Impact of Discharge Disposition on Episode-of-Care Reimbursement After Primary Total Hip Arthroplasty.

PubMed

Sabeh, Karim G; Rosas, Samuel; Buller, Leonard T; Roche, Martin W; Hernandez, Victor H

2017-10-01

Total joint arthroplasty (TJA) accounts for more Medicare expenditure than any other inpatient procedure. The Comprehensive Care for Joint Replacement model was introduced to decrease cost and improve quality in TJA. The largest portion of episode-of-care costs occurs after discharge. This study sought to quantify the cost variation of primary total hip arthroplasty (THA) according to discharge disposition. The Medicare and Humana claims databases were used to extract charges and reimbursements to compare day-of-surgery and 91-day postoperative costs simulating episode-of-care reimbursements. Of the patients who underwent primary THA, 257,120 were identified (204,912 from Medicare and 52,208 from Humana). Patients were stratified by discharge disposition: home with home health, skilled nursing facility, or inpatient rehabilitation facility. There is a significant difference in the episode-of-care costs according to discharge disposition, with discharge to an inpatient rehabilitation facility the most costly and discharge to home the least costly. Postdischarge costs represent a sizeable portion of the overall expense in THA, and optimizing patients to allow safe discharge to home may help reduce the cost of THA. Copyright © 2017 Elsevier Inc. All rights reserved.

Utility of functional status for classifying community versus institutional discharges after inpatient rehabilitation for stroke.

PubMed

Reistetter, Timothy A; Graham, James E; Deutsch, Anne; Granger, Carl V; Markello, Samuel; Ottenbacher, Kenneth J

2010-03-01

To evaluate the ability of patient functional status to differentiate between community and institutional discharges after rehabilitation for stroke. Retrospective cross-sectional design. Inpatient rehabilitation facilities contributing to the Uniform Data System for Medical Rehabilitation. Patients (N=157,066) receiving inpatient rehabilitation for stroke from 2006 and 2007. Not applicable. Discharge FIM rating and discharge setting (community vs institutional). Approximately 71% of the sample was discharged to the community. Receiver operating characteristic curve analyses revealed that FIM total performed as well as or better than FIM motor and FIM cognition subscales in differentiating discharge settings. Area under the curve for FIM total was .85, indicating very good ability to identify persons discharged to the community. A FIM total rating of 78 was identified as the optimal cut point for distinguishing between positive (community) and negative (institution) tests. This cut point yielded balanced sensitivity and specificity (both=.77). Discharge planning is complex, involving many factors. Identifying a functional threshold for classifying discharge settings can provide important information to assist in this process. Additional research is needed to determine if the risks and benefits of classification errors justify shifting the cut point to weight either sensitivity or specificity of FIM ratings. Copyright 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Composition analyzer for microparticles using a spark ion source

NASA Technical Reports Server (NTRS)

Auer, S.; Berg, O. E.

1975-01-01

Iron microparticles were fired onto a capacitor-type microparticle detector which responded to an impact with a spark discharge. Ion currents were extracted from the spark and analyzed in a time-of-flight mass spectrometer. The mass spectra showed the elements of both detector and particle materials. The total extracted ion current was typically 10 A within a period of 100 nsec, indicating very efficient vaporization of the particle and ionization of the vapor. Potential applications include research on cosmic dust, atmospheric aerosols and cloud droplets, particles ejected by rocket or jet engines, by machining processes or by nuclear bomb explosions.

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.

Comparison of two methods for estimating discharge and nutrient loads from Tidally affected reaches of the Myakka and Peace Rivers, West-Central Florida

USGS Publications Warehouse

Levesque, V.A.; Hammett, K.M.

1997-01-01

The Myakka and Peace River Basins constitute more than 60 percent of the total inflow area and contribute more than half the total tributary inflow to the Charlotte Harbor estuarine system. Water discharge and nutrient enrichment have been identified as significant concerns in the estuary, and consequently, it is important to accurately estimate the magnitude of discharges and nutrient loads transported by inflows from both rivers. Two methods for estimating discharge and nutrient loads from tidally affected reaches of the Myakka and Peace Rivers were compared. The first method was a tidal-estimation method, in which discharge and nutrient loads were estimated based on stage, water-velocity, discharge, and water-quality data collected near the mouths of the rivers. The second method was a traditional basin-ratio method in which discharge and nutrient loads at the mouths were estimated from discharge and loads measured at upstream stations. Stage and water-velocity data were collected near the river mouths by submersible instruments, deployed in situ, and discharge measurements were made with an acoustic Doppler current profiler. The data collected near the mouths of the Myakka River and Peace River were filtered, using a low-pass filter, to remove daily mixed-tide effects with periods less than about 2 days. The filtered data from near the river mouths were used to calculate daily mean discharge and nutrient loads. These tidal-estimation-method values were then compared to the basin-ratio-method values. Four separate 30-day periods of differing streamflow conditions were chosen for monitoring and comparison. Discharge and nutrient load estimates computed from the tidal-estimation and basin-ratio methods were most similar during high-flow periods. However, during high flow, the values computed from the tidal-estimation method for the Myakka and Peace Rivers were consistently lower than the values computed from the basin-ratio method. There were substantial differences between discharges and nutrient loads computed from the tidal-estimation and basin-ratio methods during low-flow periods. Furthermore, the differences between the methods were not consistent. Discharges and nutrient loads computed from the tidal-estimation method for the Myakka River were higher than those computed from the basin-ratio method, whereas discharges and nutrients loads computed by the tidal-estimation method for the Peace River were not only lower than those computed from the basin-ratio method, but they actually reflected a negative, or upstream, net movement. Short-term tidal measurement results should be used with caution, because antecedent conditions can influence the discharge and nutrient loads. Continuous tidal data collected over a 1- or 2-year period would be necessary to more accurately estimate the tidally affected discharge and nutrient loads for the Myakka and Peace River Basins.

Female genital schistosomiasis--a differential diagnosis to sexually transmitted disease: genital itch and vaginal discharge as indicators of genital Schistosoma haematobium morbidity in a cross-sectional study in endemic rural Zimbabwe.

PubMed

Kjetland, Eyrun Floerecke; Kurewa, Edith Nyaradzai; Ndhlovu, Patricia D; Midzi, Nicholas; Gwanzura, Lovemore; Mason, Peter R; Gomo, Exnevia; Sandvik, Leiv; Mduluza, Takafira; Friis, Henrik; Gundersen, Svein Gunnar

2008-12-01

To examine the association between schistosomiasis and reproductive tract symptoms. A cross-sectional study was conducted in a Schistosoma haematobium-endemic area of rural Zimbabwe. A total of 483 permanently resident adult women of Mupfure Ward aged 20-49 were interviewed and examined clinically, each providing three consecutive urine samples. Logistic regression analysis was used to control for sexually transmitted diseases (STDs). Women with genital sandy patches had significantly more genital itch (P = 0.009) and perceived their discharge as abnormal (P = 0.003). Eighty percent of the women who had genital itch, yellow discharge, and childhood or current waterbody contact had sandy patches. Fifty-two percent of the women with genital sandy patches did not have detectable S. haematobium ova in urine. Genital schistosomiasis was associated with stress incontinence and pollakisuria, but not with menstrual irregularities, current or previous ulcers, or tumours. Genital schistosomiasis may be a differential diagnosis to the STDs in women who have been exposed to fresh water in endemic areas. Because of the chronic nature of the disease in adults, we suggest to pay special attention to the prevention of morbidity.

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)

Current Density Measurements of an Annular-Geometry Ion Engine

NASA Technical Reports Server (NTRS)

Shastry, Rohit; Patterson, Michael J.; Herman, Daniel A.; Foster, John E.

2012-01-01

The concept of the annular-geometry ion engine, or AGI-Engine, has been shown to have many potential benefits when scaling electric propulsion technologies to higher power. However, the necessary asymmetric location of the discharge cathode away from thruster centerline could potentially lead to non-uniformities in the discharge not present in conventional geometry ion thrusters. In an effort to characterize the degree of this potential nonuniformity, a number of current density measurements were taken on a breadboard AGI-Engine. Fourteen button probes were used to measure the ion current density of the discharge along a perforated electrode that replaced the ion optics during conditions of simulated beam extraction. Three Faraday probes spaced apart in the vertical direction were also used in a separate test to interrogate the plume of the AGI-Engine during true beam extraction. It was determined that both the discharge and the plume of the AGI-Engine are highly uniform, with variations under most conditions limited to 10% of the average current density in the discharge and 5% of the average current density in the plume. Beam flatness parameter measured 30 mm from the ion optics ranged from 0.85 0.95, and overall uniformity was shown to generally increase with increasing discharge and beam currents. These measurements indicate that the plasma is highly uniform despite the asymmetric location of the discharge cathode.

Current Density Measurements of an Annular-Geometry Ion Engine

NASA Technical Reports Server (NTRS)

Shastry, Rohit; Patterson, Michael J.; Herman, Daniel A.; Foster, John E.

2012-01-01

The concept of the annular-geometry ion engine, or AGI-Engine, has been shown to have many potential benefits when scaling electric propulsion technologies to higher power. However, the necessary asymmetric location of the discharge cathode away from thruster centerline could potentially lead to non-uniformities in the discharge not present in conventional geometry ion thrusters. In an effort to characterize the degree of this potential non-uniformity, a number of current density measurements were taken on a breadboard AGI-Engine. Fourteen button probes were used to measure the ion current density of the discharge along a perforated electrode that replaced the ion optics during conditions of simulated beam extraction. Three Faraday probes spaced apart in the vertical direction were also used in a separate test to interrogate the plume of the AGI-Engine during true beam extraction. It was determined that both the discharge and the plume of the AGI-Engine are highly uniform, with variations under most conditions limited to +/-10% of the average current density in the discharge and +/-5% of the average current density in the plume. Beam flatness parameter measured 30 mm from the ion optics ranged from 0.85 - 0.95, and overall uniformity was shown to generally increase with increasing discharge and beam currents. These measurements indicate that the plasma is highly uniform despite the asymmetric location of the discharge cathode.

Study of the homogeneity of the current distribution in a dielectric barrier discharge in air by means of a segmented electrode

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

Malashin, M. V., E-mail: m-malashin@mail.ru; Moshkunov, S. I.; Khomich, V. Yu.

2016-02-15

The current distribution in a dielectric barrier discharge in atmospheric-pressure air at a natural humidity of 40–60% was studied experimentally with a time resolution of 200 ps. The experimental results are interpreted by means of numerically simulating the discharge electric circuit. The obtained results indicate that the discharge operating in the volumetric mode develops simultaneously over the entire transverse cross section of the discharge gap.

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.

Changes in inpatient payer-mix and hospitalizations following Medicaid expansion: Evidence from all-capture hospital discharge data.

PubMed

Freedman, Seth; Nikpay, Sayeh; Carroll, Aaron; Simon, Kosali

2017-01-01

The Affordable Care Act resulted in unprecedented reductions in the uninsured population through subsidized private insurance and an expansion of Medicaid. Early estimates from the beginning of 2014 showed that the Medicaid expansion decreased uninsured discharges and increased Medicaid discharges with no change in total discharges. To provide new estimates of the effect of the ACA on discharges for specific conditions. We compared outcomes between states that did and did not expand Medicaid using state-level all-capture discharge data from 2009-2014 for 42 states from the Healthcare Costs and Utilization Project's FastStats database; for a subset of states we used data through 2015. We stratified the analysis by baseline uninsured rates and used difference-in-differences and synthetic control methods to select comparison states with similar baseline characteristics that did not expand Medicaid. Our main outcomes were total and condition-specific hospital discharges per 1,000 population and the share of total discharges by payer. Conditions reported separately in FastStats included maternal, surgical, mental health, injury, and diabetes. The share of uninsured discharges fell in Medicaid expansion states with below (-4.39 percentage points (p.p.), -6.04 --2.73) or above (-7.66 p.p., -9.07 --6.24) median baseline uninsured rates. The share of Medicaid discharges increased in both small (6.42 p.p. 4.22-6.62) and large (10.5 p.p., 8.48-12.5) expansion states. Total and most condition-specific discharges per 1,000 residents did not change in Medicaid expansion states with high or low baseline uninsured rates relative to non-expansion states (0.418, p = 0.225), with one exception: diabetes. Discharges for that condition per 1,000 fell in states with high baseline uninsured rates relative to non-expansion states (-0.038 95% p = 0.027). Early changes in payer mix identified in the first two quarters of 2014 continued through the Medicaid expansion's first year and are distributed across all condition types studied. We found no change in total discharges between Medicaid expansion and non-expansion states, however residents of states that should have been most affected by the Medicaid expansion were less likely to be hospitalized for diabetes.

Geohydrologic Investigations and Landscape Characteristics of Areas Contributing Water to Springs, the Current River, and Jacks Fork, Ozark National Scenic Riverways, Missouri

USGS Publications Warehouse

Mugel, Douglas N.; Richards, Joseph M.; Schumacher, John G.

2009-01-01

The Ozark National Scenic Riverways (ONSR) is a narrow corridor that stretches for approximately 134 miles along the Current River and Jacks Fork in southern Missouri. Most of the water flowing in the Current River and Jacks Fork is discharged to the rivers from springs within the ONSR, and most of the recharge area of these springs is outside the ONSR. This report describes geohydrologic investigations and landscape characteristics of areas contributing water to springs and the Current River and Jacks Fork in the ONSR. The potentiometric-surface map of the study area for 2000-07 shows that the groundwater divide extends beyond the surface-water divide in some places, notably along Logan Creek and the northeastern part of the study area, indicating interbasin transfer of groundwater between surface-water basins. A low hydraulic gradient occurs in much of the upland area west of the Current River associated with areas of high sinkhole density, which indicates the presence of a network of subsurface karst conduits. The results of a low base-flow seepage run indicate that most of the discharge in the Current River and Jacks Fork was from identified springs, and a smaller amount was from tributaries whose discharge probably originated as spring discharge, or from springs or diffuse groundwater discharge in the streambed. Results of a temperature profile conducted on an 85-mile reach of the Current River indicate that the lowest average temperatures were within or downstream from inflows of springs. A mass-balance on heat calculation of the discharge of Bass Rock Spring, a previously undescribed spring, resulted in an estimated discharge of 34.1 cubic feet per second (ft3/s), making it the sixth largest spring in the Current River Basin. The 13 springs in the study area for which recharge areas have been estimated accounted for 82 percent (867 ft3/s of 1,060 ft3/s) of the discharge of the Current River at Big Spring during the 2006 seepage run. Including discharge from other springs, the cumulative discharge from springs was over 90 percent of the river discharge at most of the spring locations, and was 92 percent at Big Spring and at the lower end of the ONSR. The discharge from the 1.9-mile long Pulltite Springs Complex measured in the 2006 seepage run was 88 ft3/s. Most of this (77 ft3/s) was from the first approximately 0.25 mi of the Pulltite Springs Complex. It has been estimated that the annual mean discharge from the Current River Springs Complex is 125 ft3/s, based on an apparent discharge of 50 ft3/s during a 1966 U.S. Geological Survey seepage run. However, a reinterpretation of the 1966 seepage run data shows that the discharge from the Current River Springs Complex instead was about 12.6 ft3/s, and the annual mean discharge was estimated to be 32 ft3/s, substantially less than 125 ft3/s. The 2006 seepage run showed a gain of only 12 ft3/s from the combined Round Spring and Current River Springs Complex from the mouth of Sinking Creek to 0.7 mi upstream from Root Hollow. The 2006 temperature profile measurements did not indicate any influx of spring discharge throughout the length of the Current River Springs Complex. The spring recharge areas with the largest number of identified sinkholes are Big Spring, Alley Spring, and Welch Spring. The spring recharge areas with the largest number of sinkholes per square mile of recharge area are Alley Spring, Blue Spring (Jacks Fork), Welch Spring, and Round Spring and the Current River Springs Complex. Using the currently known locations of losing streams, the Big Spring recharge area has the largest number of miles of losing stream, and the Bass Rock Spring recharge area has the largest number of miles of losing stream per unit recharge area. The spring recharge areas with the most open land and the least forested land per unit recharge area are Blue Spring (Jacks Fork), Welch Spring, Montauk Springs, and Alley Spring. The spring recharge areas with the least amount

On the road to self-sputtering in high power impulse magnetron sputtering: particle balance and discharge characteristics

NASA Astrophysics Data System (ADS)

Huo, Chunqing; Lundin, Daniel; Raadu, Michael A.; Anders, André; Tomas Gudmundsson, Jon; Brenning, Nils

2014-04-01

The onset and development of self-sputtering (SS) in a high power impulse magnetron sputtering (HiPIMS) discharge have been studied using a plasma chemical model and a set of experimental data, taken with an aluminum target and argon gas. The model is tailored to duplicate the discharge in which the data are taken. The pulses are long enough to include both an initial transient and a following steady state. The model is used to unravel how the internal discharge physics evolves with pulse power and time, and how it is related to features in the discharge current-voltage-time characteristics such as current densities, maxima, kinks and slopes. The connection between the self-sputter process and the discharge characteristics is quantified and discussed in terms of three parameters: a critical target current density Jcrit based on the maximum refill rate of process (argon) gas above the target, an SS recycling factor ΠSS-recycle, and an approximation \\tilde{\\alpha} of the probabilities of ionization of species that come from the target (both sputtered metal and embedded argon atoms). For low power pulses, discharge voltages UD ⩽ 380 V with peak current densities below ≈ 0.2 A cm-2, the discharge is found to be dominated by process gas sputtering. In these pulses there is an initial current peak in time, associated with partial gas rarefaction, which is followed by a steady-state-like plateau in all parameters similar to direct current magnetron sputtering. In contrast, high power pulses, with UD ⩾ 500 V and peak current densities above JD ≈ 1.6 A cm-2, make a transition to a discharge mode where SS dominates. The transition is found not to be driven by process gas rarefaction which is only about 10% at this time. Maximum gas rarefaction is found later in time and always after the initial peak in the discharge current. With increasing voltage, and pulse power, the discharge can be described as following a route where the role of SS increases in four steps: process gas sputtering, gas-sustained SS, self-sustained SS and SS runaway. At the highest voltage, 1000 V, the discharge is very close to, but does not go into, the SS runaway mode. This absence of runaway is proposed to be connected to an unexpected finding: that twice ionized ions of the target species play almost no role in this discharge, not even at the highest powers. This reduces ionization by secondary-emitted energetic electrons almost to zero in the highest power range of the discharge.

Electric characteristics of a surface barrier discharge with a plasma induction electrode

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

Alemskii, I. N.; Lelevkin, V. M.; Tokarev, A. V.

2006-07-15

Static and dynamic current-voltage and charge-voltage characteristics of a surface barrier discharge with a plasma induction electrode have been investigated experimentally. The dependences of the discharge current on both the gas pressure in the induction electrode tube and the winding pitch of the corona electrode, as well as of the discharge power efficiency on the applied voltage, have been measured.

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.

Influence of water conductivity on particular electrospray modes with dc corona discharge — optical visualization approach

NASA Astrophysics Data System (ADS)

Pongrác, Branislav; Kim, Hyun-Ha; Negishi, Nobuaki; Machala, Zdenko

2014-08-01

The effect of water conductivity on electrospraying of water was studied in combination with positive DC corona discharge generated in air. We used a point-to-plane geometry of electrodes with a hollow syringe needle anode opposite to the metal mesh cathode. We employed total average current measurements and high-speed camera fast time-resolved imaging. We visualized the formation of a water jet (filament) and investigated corona discharge behavior for various water conductivities. Depending on the conductivity, various jet properties were observed: pointy, prolonged, and fast spreading water filaments for lower conductivity; in contrast to rounder, broader, and shorter quickly disintegrating filaments for higher conductivity. The large acceleration values (4060 m/s2 and 520 m/s2 for 2 μS/cm and 400 μS/cm, respectively) indicate that the process is mainly governed by the electrostatic force. In addition, with increasing conductivity, the breakdown voltage for corona-to-spark transition was decreasing.

Method and apparatus for determining time, direction, and composition of impacting space particles

NASA Technical Reports Server (NTRS)

Kinard, William H. (Inventor); Wortman, Jim J. (Inventor); Kassel, Philip C., Jr. (Inventor); Singer, Fred S. (Inventor); Humes, Donald H. (Inventor); Stanley, John E. (Inventor)

1990-01-01

A space particle collector for recording the time specific particles are captured, and its direction at the time of capture, utilizes an array of targets, each comprised of an MOS capacitor on a chip charged from an external source and discharged upon impact by a particle through a tab on the chip that serves as a fuse. Any impacting particle creates a crater, but only the first will cause a discharge of the capacitor. A substantial part of the metal film around the first crater is burned off by the discharge current. The time of the impulse which burns the tab, and the identification of the target, is recorded together with data from flight instruments. The metal film is partitioned into pie sections to provide a plurality of targets on each of an array of silicon wafers, thus increasing the total number of identified particles that can be collected. It is thus certain which particles were captured at what specific times.

Influence of Sample Size of Polymer Materials on Aging Characteristics in the Salt Fog Test

NASA Astrophysics Data System (ADS)

Otsubo, Masahisa; Anami, Naoya; Yamashita, Seiji; Honda, Chikahisa; Takenouchi, Osamu; Hashimoto, Yousuke

Polymer insulators have been used in worldwide because of some superior properties; light weight, high mechanical strength, good hydrophobicity etc., as compared with porcelain insulators. In this paper, effect of sample size on the aging characteristics in the salt fog test is examined. Leakage current was measured by using 100 MHz AD board or 100 MHz digital oscilloscope and separated three components as conductive current, corona discharge current and dry band arc discharge current by using FFT and the current differential method newly proposed. Each component cumulative charge was estimated automatically by a personal computer. As the results, when the sample size increased under the same average applied electric field, the peak values of leakage current and each component current increased. Especially, the cumulative charges and the arc discharge length of dry band arc discharge increased remarkably with the increase of gap length.

Spatial Characteristics and Driving Factors of Provincial Wastewater Discharge in China

PubMed Central

Chen, Kunlun; Liu, Xiaoqiong; Ding, Lei; Huang, Gengzhi; Li, Zhigang

2016-01-01

Based on the increasing pressure on the water environment, this study aims to clarify the overall status of wastewater discharge in China, including the spatio-temporal distribution characteristics of wastewater discharge and its driving factors, so as to provide reference for developing “emission reduction” strategies in China and discuss regional sustainable development and resources environment policies. We utilized the Exploratory Spatial Data Analysis (ESDA) method to analyze the characteristics of the spatio-temporal distribution of the total wastewater discharge among 31 provinces in China from 2002 to 2013. Then, we discussed about the driving factors, affected the wastewater discharge through the Logarithmic Mean Divisia Index (LMDI) method and classified those driving factors. Results indicate that: (1) the total wastewater discharge steadily increased, based on the social economic development, with an average growth rate of 5.3% per year; the domestic wastewater discharge is the main source of total wastewater discharge, and the amount of domestic wastewater discharge is larger than the industrial wastewater discharge. There are many spatial differences of wastewater discharge among provinces via the ESDA method. For example, provinces with high wastewater discharge are mainly the developed coastal provinces such as Jiangsu Province and Guangdong Province. Provinces and their surrounding areas with low wastewater discharge are mainly the undeveloped ones in Northwest China; (2) The dominant factors affecting wastewater discharge are the economy and technological advance; The secondary one is the efficiency of resource utilization, which brings about the unstable effect; population plays a less important role in wastewater discharge. The dominant driving factors affecting wastewater discharge among 31 provinces are divided into three types, including two-factor dominant type, three-factor leading type and four-factor antagonistic type. In addition, the proposals aimed at reducing the wastewater discharge are provided on the basis of these three types. PMID:27941698

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.

Discharge Oscillations in a Permanent Magnet Cylindrical Hall-Effect Thruster

NASA Technical Reports Server (NTRS)

Polzin, K. A.; Sooby, E. S.; Raitses, Y.; Merino, E.; Fisch, N. J.

2009-01-01

Measurements of the discharge current in a cylindrical Hall thruster are presented to quantify plasma oscillations and instabilities without introducing an intrusive probe into the plasma. The time-varying component of the discharge current is measured using a current monitor that possesses a wide frequency bandwidth and the signal is Fourier transformed to yield the frequency spectra present, allowing for the identification of plasma oscillations. The data show that the discharge current oscillations become generally greater in amplitude and complexity as the voltage is increased, and are reduced in severity with increasing flow rate. The breathing mode ionization instability is identified, with frequency as a function of discharge voltage not increasing with discharge voltage as has been observed in some traditional Hall thruster geometries, but instead following a scaling similar to a large-amplitude, nonlinear oscillation mode recently predicted in for annular Hall thrusters. A transition from lower amplitude oscillations to large relative fluctuations in the oscillating discharge current is observed at low flow rates and is suppressed as the mass flow rate is increased. A second set of peaks in the frequency spectra are observed at the highest propellant flow rate tested. Possible mechanisms that might give rise to these peaks include ionization instabilities and interactions between various oscillatory modes.

38 CFR 4.30 - Convalescent ratings.

Code of Federal Regulations, 2010 CFR

2010-07-01

... RATING DISABILITIES General Policy in Rating § 4.30 Convalescent ratings. A total disability rating (100... by report at hospital discharge (regular discharge or release to non-bed care) or outpatient release... total ratings will not be subject to § 3.105(e) of this chapter. Such total rating will be followed by...

Terrestrial Sediment and Nutrient Discharge, and Their Potential Influence on Coral Reefs, Puerto Rico

NASA Astrophysics Data System (ADS)

Larsen, M. C.; Webb, R. M.; Warne, A. G.

2004-12-01

Sediment and nutrient discharge to the insular shelf of Puerto Rico (18 degrees latitude), augmented by anthropogenic activity, is believed to have contributed to widespread degradation of coral reefs of Puerto Rico during the 20th century. Sediment deposition degrades coral reefs because it reduces the area of sea floor suitable for growth of new coral, diminishes the amount of light available for photosynthesis by symbiotic algae that live within individual coral animals, and in extreme cases, buries coral colonies. Land-use history and data from 30 water-discharge, 9 daily and 15 intermittent sediment-concentration, and 24 water-quality gaging stations were analyzed to investigate the timing and intensity of terrestrial sediment and nutrient discharge into coastal waters. Watersheds in Puerto Rico generally are small (10's to 100's of square km), channel gradients are steep, and stream valleys are deeply incised and narrow. Major storms are usually brief (<24 h) but intense such that the majority of the annual sediment discharge occurs in a few days. From 1960 through 2000 the highest mean daily discharge for a water year (October - September) accounted for 20 to 60 percent of the total annual sediment discharge. Major storms, with a return frequency of approximately a decade, were capable of discharging up to 30 times the median annual sediment-discharge volume. Prior to agricultural and industrial development, coastal waters are believed to have been relatively transparent, with strong currents and seasonal high-energy swells assisting corals in the removal of minor amounts of sediment deposited after storms. Land clearing and modification, first for agriculture and later for urban development, have increased sediment and nutrient influx to the coast during the 19th and 20th centuries. Although forest cover has increased to approximately 30 percent of the surface of Puerto Rico during the past 60 years, sediment eroded from hillslopes during the agricultural period is still being episodically transported from upland valleys to downstream floodplains and the coast. In response to better land management, the quality of water has improved significantly since the 1980s. Nitrogen and phosphorous concentrations in river waters are now well within regulatory limits, although current concentrations are as much as 10 times the estimated pre-settlement levels. Concentrations of pathogens also are improved but continue to be near or above regulatory limits. Unlike sediment discharge, which is episodic and intense, the discharge of river-borne nutrients and pathogens is a less intense but chronic stressor to coral reefs located near the mouths of rivers.

Effect of Risk Acceptance for Bundled Care Payments on Clinical Outcomes in a High-Volume Total Joint Arthroplasty Practice After Implementation of a Standardized Clinical Pathway.

PubMed

Kee, James R; Edwards, Paul K; Barnes, Charles L

2017-08-01

The Bundled Payments for Care Improvement (BPCI) initiative and the Arkansas Payment Improvement (API) initiative seek to incentivize reduced costs and improved outcomes compared with the previous fee-for-service model. Before participation, our practice initiated a standardized clinical pathway (CP) to reduce length of stay (LOS), readmissions, and discharge to postacute care facilities. This practice implemented a standardized CP focused on patient education, managing patient expectations, and maximizing cost outcomes. We retrospectively reviewed all primary total joint arthroplasty patients during the initial 2-year "at risk" period for both BPCI and API and determined discharge disposition, LOS, and readmission rate. During the "at risk" period, the average LOS decreased in our total joint arthroplasty patients and our patients discharged home >94%. Patients within the BPCI group had a decreased discharge to home and decreased readmission rates after total hip arthroplasty, but also tended to be older than both API and nonbundled payment patients. While participating in the BPCI and API, continued use of a standardized CP in a high-performing, high-volume total joint practice resulted in maintenance of a low-average LOS. In addition, BPCI patients had similar outcomes after total knee arthroplasty, but had decreased rates of discharge to home and readmission after total hip arthroplasty. Copyright © 2017 Elsevier Inc. All rights reserved.

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

Apparatus for producing voltage and current pulses

DOEpatents

Kirbie, Hugh; Dale, Gregory E.

2010-12-21

An apparatus having one or more modular stages for producing voltage and current pulses. Each module includes a diode charging means to charge a capacitive means that stores energy. One or more charging impedance means are connected to the diode charging means to provide a return current pathway. A solid-state switch discharge means, with current interruption capability, is connected to the capacitive means to discharge stored energy. Finally, a control means is provided to command the switching action of the solid-state switch discharge means.

Discharge indices for water quality loads

USGS Publications Warehouse

Vogel, Richard M.; Stedinger, Jery R.; Hooper, Richard P.

2003-01-01

Effective discharge has been used to describe the streamflow level that is responsible for transporting the most sediment over the long term. Careful inspection reveals that this concept may not have been well defined, and different interpretations have led to conflicting representations. Because total load is ultimately the quantity of interest, we define a new index, the half‐load discharge, which is that discharge above and below which half the total long‐term load is transported. The value of the half‐load discharge is derived for a reasonable model of flows and constituent concentration. The effective discharge has generally been thought to be a relatively common or frequent flood. The half‐load discharge is generally a much greater and less frequent flow than commonly used estimators of the effective discharge. Relations provided here for the frequency and magnitude of the half‐load discharge provide evidence that it is relatively rare floods that transport most of the sediment over the long term. These ideas apply to other constituents as well.

Current discharge management of acute coronary syndromes: baseline results from a national quality improvement initiative.

PubMed

Wai, A; Pulver, L K; Oliver, K; Thompson, A

2012-05-01

Evidence-practice gaps exist in the continuum of care for patients with acute coronary syndromes (ACS), particularly at hospital discharge. We aimed to describe the methodology and baseline results of the Discharge Management of Acute Coronary Syndromes (DMACS) project, focusing on the prescription of guideline-recommended medications, referral to cardiac rehabilitation and communication between the hospital, patient and their primary healthcare professionals. DMACS employed Drug Use Evaluation methodology involving data collection, evaluation and feedback, and targeted educational interventions. Adult patients with ACS discharged during a 4-month period were eligible to participate. Data were collected (maximum 50 patients) at each site through an inpatient medical record review, a general practitioner (GP) postal/fax survey conducted 14 days post discharge and a patient telephone survey 3 months post discharge. Forty-nine hospitals participated in the audit recruiting 1545 patients. At discharge, 57% of patients were prescribed a combination of antiplatelet agent(s), beta-blocker, statin and angiotensin-converting enzyme inhibitor and/or angiotensin II-antagonist. At 3 months post discharge, 48% of patients reported using the same combination. Some 67% of patients recalled being referred to cardiac rehabilitation; of these, 33% had completed the programme. In total, 83% of patients had a documented ACS management plan at discharge. Of these, 90% included a medication list, 56% a chest pain action plan and 54% risk factor modification advice. Overall, 65% of GPs rated the quality of information received in the discharge summary as 'very good' to 'excellent'. The findings of our baseline audit showed that despite the robust evidence base and availability of national guidelines, the management of patients with ACS can be improved. These findings will inform a multifaceted intervention strategy to improve adherence to guidelines for the discharge management of patients with ACS. © 2010 The Authors. Internal Medicine Journal © 2010 Royal Australasian College of Physicians.

Field evaluation of boat-mounted acoustic Doppler instruments used to measure streamflow

USGS Publications Warehouse

Mueller, D.S.; ,

2003-01-01

The use of instruments based on the Doppler principle for measuring water velocity and computing discharge is common within the U.S. Geological Survey (USGS). The instruments and software have changed appreciably during the last 5 years; therefore, the USGS has begun field validation of the instruments used to make discharge measurements from a moving boat. Instruments manufactured by SonTek/YSI and RD Instruments, Inc. were used to collect discharge data at five different sites. One or more traditional discharge measurements were made using a Price AA current meter and standard USGS procedures concurrent with the acoustic instruments at each site. Discharges measured with the acoustic instruments were compared with discharges measured with Price AA current meters and the USGS stage-discharge rating for each site. The mean discharges measured by each acoustic instrument were within 5 percent of the Price AA-based measurement and (or) discharge from the stage-discharge rating.

An experimental system for controlled exposure of biological samples to electrostatic discharges.

PubMed

Marjanovič, Igor; Kotnik, Tadej

2013-12-01

Electrostatic discharges occur naturally as lightning strokes, and artificially in light sources and in materials processing. When an electrostatic discharge interacts with living matter, the basic physical effects can be accompanied by biophysical and biochemical phenomena, including cell excitation, electroporation, and electrofusion. To study these phenomena, we developed an experimental system that provides easy sample insertion and removal, protection from airborne particles, observability during the experiment, accurate discharge origin positioning, discharge delivery into the sample either through an electric arc with adjustable air gap width or through direct contact, and reliable electrical insulation where required. We tested the system by assessing irreversible electroporation of Escherichia coli bacteria (15 mm discharge arc, 100 A peak current, 0.1 μs zero-to-peak time, 0.2 μs peak-to-halving time), and gene electrotransfer into CHO cells (7 mm discharge arc, 14 A peak current, 0.5 μs zero-to-peak time, 1.0 μs peak-to-halving time). Exposures to natural lightning stroke can also be studied with this system, as due to radial current dissipation, the conditions achieved by a stroke at a particular distance from its entry are also achieved by an artificial discharge with electric current downscaled in magnitude, but similar in time course, correspondingly closer to its entry. © 2013.

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.

Self-similar magnetohydrodynamic model for direct current discharge fireball experiments

NASA Astrophysics Data System (ADS)

Tsui, K. H.; Navia, C. E.; Robba, M. B.; Carneiro, L. T.; Emelin, S. E.

2006-11-01

Ball lightning models and corresponding laboratory efforts in generating fireballs are briefly summarized to give an overview of the current status. In particular, emphasis is given to direct current discharge experiments at atmospheric pressure such as capillary discharge with a plasma plume in front of the anode opening [Emelin et al., Tech. Phys. Letters 23, 758 (1997)] and water resistor discharge with fluttering fireball overhead [Egorov and Stepanov, Tech. Phys. 47, 1584 (2002)]. These fireballs are interpreted as laboratory demonstrations of the self-similar magnetohydrodynamic (MHD) model of ball lightning [Tsui, Phys. Plasmas 13, 072102 (2006)].

Effects of River Discharge and Land Use and Land Cover (LULC) on Water Quality Dynamics in Migina Catchment, Rwanda

NASA Astrophysics Data System (ADS)

Uwimana, Abias; van Dam, Anne; Gettel, Gretchen; Bigirimana, Bonfils; Irvine, Kenneth

2017-09-01

Agricultural intensification may accelerate the loss of wetlands, increasing the concentrations of nutrients and sediments in downstream water bodies. The objective of this study was to assess the effects of land use and land cover and river discharge on water quality in the Migina catchment, southern Rwanda. Rainfall, discharge and water quality (total nitrogen, total phosphorus, total suspended solids, dissolved oxygen, conductivity, pH, and temperature) were measured in different periods from May 2009 to June 2013. In 2011, measurements were done at the outlets of 3 sub-catchments (Munyazi, Mukura and Akagera). Between May 2012 and May 2013 the measurements were done in 16 reaches of Munyazi dominated by rice, vegetables, grass/forest or ponds/reservoirs. Water quality was also measured during two rainfall events. Results showed seasonal trends in water quality associated with high water flows and farming activities. Across all sites, the total suspended solids related positively to discharge, increasing 2-8 times during high flow periods. Conductivity, temperature, dissolved oxygen, and pH decreased with increasing discharge, while total nitrogen and total phosphorus did not show a clear pattern. The total suspended solids concentrations were consistently higher downstream of reaches dominated by rice and vegetable farming. For total nitrogen and total phosphorus results were mixed, but suggesting higher concentration of total nitrogen and total phosphorus during the dry and early rainy (and farming) season, and then wash out during the rainy season, with subsequent dilution at the end of the rains. Rice and vegetable farming generate the transport of sediment as opposed to ponds/reservoir and grass/forest.

Alternate charging and discharging of capacitor to enhance the electron production of bioelectrochemical systems.

PubMed

Liang, Peng; Wu, Wenlong; Wei, Jincheng; Yuan, Lulu; Xia, Xue; Huang, Xia

2011-08-01

A bioelectrochemical system (BES) can be operated in both "microbial fuel cell" (MFC) and "microbial electrolysis cell" (MEC) modes, in which power is delivered and invested respectively. To enhance the electric current production, a BES was operated in MFC mode first and a capacitor was used to collect power from the system. Then the charged capacitor discharged electrons to the system itself, switching into MEC mode. This alternate charging and discharging (ACD) mode helped the system produce 22-32% higher average current compared to an intermittent charging (IC) mode, in which the capacitor was first charged from an MFC and then discharged to a resistor, at 21.6 Ω external resistance, 3.3 F capacitance and 300 mV charging voltage. The effects of external resistance, capacitance and charging voltage on average current were studied. The average current reduced as the external resistance and charging voltage increased and was slightly affected by the capacitance. Acquisition of higher average current in the ACD mode was attributed to the shorter discharging time compared to the charging time, as well as a higher anode potential caused by discharging the capacitor. Results from circuit analysis and quantitatively calculation were consistent with the experimental observations.

A Reactor Development Scenario for the FUZE Shear-flow Stabilized Z-pinch

NASA Astrophysics Data System (ADS)

McLean, H. S.; Higginson, D. P.; Schmidt, A.; Tummel, K. K.; Shumlak, U.; Nelson, B. A.; Claveau, E. L.; Golingo, R. P.; Weber, T. R.

2016-10-01

We present a conceptual design, scaling calculations, and a development path for a pulsed fusion reactor based on the shear-flow-stabilized Z-pinch device. Experiments performed on the ZaP device have demonstrated stable operation for 40 us at 150 kA total discharge current (with 100 kA in the pinch) for pinches that are 1cm in diameter and 100 cm long. Scaling calculations show that achieving stabilization for a pulse of 100 usec, for discharge current 1.5 MA, in a shortened pinch 50 cm, results in a pinch diameter of 200 um and a reactor plant Q 5 for reasonable assumptions of the various system efficiencies. We propose several key intermediate performance levels in order to justify further development. These include achieving operation at pinch currents of 300 kA, where Te and Ti are calculated to exceed 1 keV, 700 kA where fusion power exceeds pinch input power, and 1 MA where fusion energy per pulse exceeds input energy per pulse. This work funded by USDOE ARPAe ALPHA Program and performed under the auspices of Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-697801.

Modeling of anomalous electron mobility in Hall thrusters

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

Koo, Justin W.; Boyd, Iain D.

Accurate modeling of the anomalous electron mobility is absolutely critical for successful simulation of Hall thrusters. In this work, existing computational models for the anomalous electron mobility are used to simulate the UM/AFRL P5 Hall thruster (a 5 kW laboratory model) in a two-dimensional axisymmetric hybrid particle-in-cell Monte Carlo collision code. Comparison to experimental results indicates that, while these computational models can be tuned to reproduce the correct thrust or discharge current, it is very difficult to match all integrated performance parameters (thrust, power, discharge current, etc.) simultaneously. Furthermore, multiple configurations of these computational models can produce reasonable integrated performancemore » parameters. A semiempirical electron mobility profile is constructed from a combination of internal experimental data and modeling assumptions. This semiempirical electron mobility profile is used in the code and results in more accurate simulation of both the integrated performance parameters and the mean potential profile of the thruster. Results indicate that the anomalous electron mobility, while absolutely necessary in the near-field region, provides a substantially smaller contribution to the total electron mobility in the high Hall current region near the thruster exit plane.« less

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.

The POP Program: the patient education advantage.

PubMed

Claeys, M; Mosher, C; Reesman, D

1998-01-01

In 1992, a preoperative education program was developed for total joint replacement patients in a small community hospital. The goals of the program were to increase educational opportunities for the joint replacement patients, prepare patients for hospitalization, plan for discharge needs, and increase efficiency of the orthopaedic program. Since 1992, approximately 600 patients have attended the education program. Outcomes have included positive responses from patients regarding their preparedness for surgery, increased participation in their plan of care, coordinated discharge planning, decreased length of stay, and progression across the continuum of care. A multidisciplinary approach to preparing patients for surgery allows for a comprehensive and efficient education program. Marketing of successful programs can enhance an institution's competitive advantage and help ensure the hospital's viability in the current health care arena.

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.

Stability analysis of ELMs in long-pulse discharges with ELITE code on EAST tokamak

NASA Astrophysics Data System (ADS)

Wang, Y. F.; Xu, G. S.; Wan, B. N.; Li, G. Q.; Yan, N.; Li, Y. L.; Wang, H. Q.; Peng, Y.-K. Martin; Xia, T. Y.; Ding, S. Y.; Chen, R.; Yang, Q. Q.; Liu, H. Q.; Zang, Q.; Zhang, T.; Lyu, B.; Xu, J. C.; Feng, W.; Wang, L.; Chen, Y. J.; Luo, Z. P.; Hu, G. H.; Zhang, W.; Shao, L. M.; Ye, Y.; Lan, H.; Chen, L.; Li, J.; Zhao, N.; Wang, Q.; Snyder, P. B.; Liang, Y.; Qian, J. P.; Gong, X. Z.; EAST team

2018-05-01

One challenge in long-pulse and high performance tokamak operation is to control the edge localized modes (ELMs) to reduce the transient heat load on plasma facing components. Minute-scale discharges in H-mode have been achieved repeatedly on Experimental Advanced Superconducting Tokamak (EAST) since the 2016 campaign and understanding the characteristics of the ELMs in these discharges can be helpful for effective ELM control in long-pulse discharges. The kinetic profile diagnostics recently developed on EAST make it possible to perform the pedestal stability analysis quantitatively. Pedestal stability calculation of a typical long-pulse discharge with ELITE code is presented. The ideal linear stability results show that the ELM is dominated by toroidal mode number n around 10–15 and the most unstable mode structure is mainly localized in the steep pressure gradient region, which is consistent with experimental results. Compared with a typical type-I ELM discharge with larger total plasma current (I p = 600 kA), pedestal in the long-pulse H-mode discharge (I p = 450 kA) is more stable in peeling-ballooning instability and its critical peak pressure gradient is evaluated to be 65% of the former. Two important features of EAST tokamak in the long-pulse discharge are presented by comparison with other tokamaks, including a wider pedestal correlated with the poloidal pedestal beta and a smaller inverse aspect ratio and their effects on the pedestal stability are discussed. The effects of uncertainties in measurements on the linear stability results are also analyzed, including the edge electron density profile position, the separatrix position and the line-averaged effective ion charge {Z}{{e}{{f}}{{f}}} value.

Nursing diagnoses, diagnosis-related group, and hospital outcomes.

PubMed

Welton, John M; Halloran, Edward J

2005-12-01

There are no nursing centric data in the hospital discharge abstract. This study investigates whether adding nursing data in the form of nursing diagnoses to medical diagnostic data in the discharge abstract can improve overall explanation of variance in commonly studied hospital outcomes. A retrospective analyses of 123,241 sequential patient admissions to a university hospital in a Midwestern city was performed. Two data sets were combined: (1) a daily collection of patient assessments by nurses using nursing diagnosis terminology (NDX); and (2) the summary discharge information from the hospital discharge abstract including diagnosis-related group (DRG) and all payer refined DRG (APR-DRG). Each of 61 daily NDX observations were collapsed as frequency of occurrence for the hospital stay and inserted into the discharge abstract. NDX was then compared to both DRG and APR-DRG across 5 hospital outcome variables using multivariate regression or logistic regression. In all statistical models, DRG, APR-DRG, and NDX were significantly associated with the 5 hospital outcome variables (P <.0001). When NDX was added to models containing either the DRG or the APR-DRG, explanatory power (R2) and model discrimination (c statistic) improved by 30% to 146% across the outcome variables of hospital length of stay, ICU length of stay, total charges, probably of death, and discharge to a nursing home (P <.0001). The findings support the contention that nursing care is an independent predictor of patient hospital outcomes. These nursing data are not redundant with the medical diagnosis, in particular, the DRG. The findings support the argument for including nursing care data in the hospital discharge abstract. Further study is needed to clarify which nursing data are the best fit for the current hospital discharge abstract data collection scheme.

Sources and sinks of filtered total mercury and concentrations of total mercury of solids and of filtered methylmercury, Sinclair Inlet, Kitsap County, Washington, 2007-10

USGS Publications Warehouse

Paulson, Anthony J.; Dinicola, Richard S.; Noble, Marlene A.; Wagner, Richard J.; Huffman, Raegan L.; Moran, Patrick W.; DeWild, John F.

2012-01-01

The majority of filtered total mercury in the marine water of Sinclair Inlet originates from salt water flowing from Puget Sound. About 420 grams of filtered total mercury are added to Sinclair Inlet each year from atmospheric, terrestrial, and sedimentary sources, which has increased filtered total mercury concentrations in Sinclair Inlet (0.33 nanograms per liter) to concentrations greater than those of the Puget Sound (0.2 nanograms per liter). The category with the largest loading of filtered total mercury to Sinclair Inlet included diffusion of porewaters from marine sediment to the water column of Sinclair Inlet and discharge through the largest stormwater drain on the Bremerton naval complex, Bremerton, Washington. However, few data are available to estimate porewater and stormwater releases with any certainty. The release from the stormwater drain does not originate from overland flow of stormwater. Rather total mercury on soils is extracted by the chloride ions in seawater as the stormwater is drained and adjacent soils are flushed with seawater by tidal pumping. Filtered total mercury released by an unknown freshwater mechanism also was observed in the stormwater flowing through this drain. Direct atmospheric deposition on the Sinclair Inlet, freshwater discharge from creek and stormwater basins draining into Sinclair Inlet, and saline discharges from the dry dock sumps of the naval complex are included in the next largest loading category of sources of filtered total mercury. Individual discharges from a municipal wastewater treatment plant and from the industrial steam plant of the naval complex constituted the loading category with the third largest loadings. Stormwater discharge from the shipyard portion of the naval complex and groundwater discharge from the base are included in the loading category with the smallest loading of filtered total mercury. Presently, the origins of the solids depositing to the sediment of Sinclair Inlet are uncertain, and consequently, concentrations of sediments can be qualitatively compared only to total mercury concentrations of solids suspended in the water column. Concentrations of total mercury of suspended solids from creeks, stormwater, and even wastewater effluent discharging into greater Sinclair Inlet were comparable to concentrations of solids suspended in the water column of Sinclair Inlet. Concentrations of total mercury of suspended solids were significantly lower than those of marine bed sediment of Sinclair Inlet; these suspended solids have been shown to settle in Sinclair Inlet. The settling of suspended solids in the greater Sinclair Inlet and in Operable Unit B Marine of the naval complex likely will result in lower concentrations of total mercury in sediments. Such a decrease in total mercury concentrations was observed in the sediment of Operable Unit B Marine in 2010. However, total mercury concentrations of solids discharged from several sources from the Bremerton naval complex were higher than concentrations in sediment collected from Operable Unit B Marine. The combined loading of solids from these sources is small compared to the amount of solids depositing in OU B Marine. However, total mercury concentration in sediment collected at a monitoring station just offshore one of these sources, the largest stormwater drain on the Bremerton naval complex, increased considerably in 2010. Low methylmercury concentrations were detected in groundwater, stormwater, and effluents discharged from the Bremerton naval complex. The highest methylmercury concentrations were measured in the porewaters of highly reducing marine sediment in greater Sinclair Inlet. The marine sediment collected off the largest stormwater drain contained low concentrations of methylmercury in porewater because these sediments were not highly reducing.

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.

Investigations of Sediment Transportation, Middle Loup River at Dunning, Nebraska: With Application of Data from Turbulence Flume

USGS Publications Warehouse

Hubbell, David Wellington; Matejka, Donald Quintin

1959-01-01

An investigation of fluvial sediments of the Middle Loup River at Dunning, Nebr., was begun in 1946 and expanded in 1949 to provide information on sediment transportation. Construction of an artificial turbulence flume at which the total sediment discharge of the Middle Loup River at Dunning, Nebr., could be measured with suspended-sediment sampling equipment was completed in 1949. Since that time. measurements have been made at the turbulence flume and at several selected sections in a reach upstream and downstream from the flume. The Middle Loup River upstream from Dunning traverses the sandhills region of north-central Nebraska and has a drainage area of approximately 1,760 square miles. The sandhills are underlain by the Ogallala formation of Tertiary age and are mantled by loess and dune sand. The topography is characterized by northwest-trending sand dunes, which are stabilized by grass cover. The valley floor upstream from Dunning is generally about half a mile wide, is about 80 feet lower than the uplands, and is composed of sand that was mostly stream deposited. The channel is defined by low banks. Bank erosion is prevalent and is the source of most of the sediment load. The flow originates mostly from ground-water accretion and varies between about 200 and 600 cfs (cubic feet per second). Measured suspended-sediment loads vary from about 200 to 2,000 tons per day, of which about 20 percent is finer than 0.062 millimeter and 100 percent is finer than 0.50 millimeter. Total sediment discharges vary from about 500 to 3,500 tons per day, of which about 10 percent is finer than 0.062 millimeter, about 90 percent is finer than 0.50 millimeter, and about 98 percent is finer than 2.0 millimeters. The measured suspended-sediment discharge in the reach near Dunning averages about one-half of the total sediment discharge as measured at the turbulence flume. This report contains information collected during the period October 1, 1948, to September 30, 1952. The information includes sediment discharges; particle-size analyses of total load, of measured suspended sediment, and of bed material; water discharges and other hydraulic data for the turbulence flume and the selected sections. Sediment discharges have been computed with several different formulas, and insofar as possible, each computed load has been compared with data from the turbulence flume. Sediment discharges computed with the Einstein procedure did not agree well, in general, with comparable measured loads. However, a satisfactory representative cross section for the reach could not be determined with the cross sections that were selected for this investigation. If the computed cross section was narrower and deeper than a representative cross section for the reach, computed loads were high; and if the computed cross section was wider and shallower than a representative cross section for the reach, computed loads were low. Total sediment discharges computed with the modified Einstein procedure compared very well with the loads of individual size ranges and the measured total loads at the turbulence flume. Sediment discharges computed with the Straub equation averaged about twice the measured total sediment discharge at the turbulence flume. Bed-load discharges computed with the Kalinske equation were of about the right magnitude; however, high computed loads were associated with low total loads, low unmeasured loads, and low concentrations of measured suspended sediment coarser than 0.125 millimeter. Bed-load discharges computed with the Schoklitsch equation seemed somewhat high; about one-third of the computed loads were slightly higher than comparable unmeasured loads. Although, in general, high computed discharges with the Schoklitsch equation were associated with high measured total loads, high unmeasured loads, and high concentrations of measured suspended sediment coarser than 0.125 millimeter, the trend was not consistent. Bed-load discharges computed

Concentration and flux of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids for monitored tributaries of Lake Champlain, 1990-2012

USGS Publications Warehouse

Medalie, Laura

2014-01-01

Annual and daily concentrations and fluxes of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids were estimated for 18 monitored tributaries to Lake Champlain by using the Weighted Regressions on Time, Discharge, and Seasons regression model. Estimates were made for 21 or 23 years, depending on data availability, for the purpose of providing timely and accessible summary reports as stipulated in the 2010 update to the Lake Champlain “Opportunities for Action” management plan. Estimates of concentration and flux were provided for each tributary based on (1) observed daily discharges and (2) a flow-normalizing procedure, which removed the random fluctuations of climate-related variability. The flux bias statistic, an indicator of the ability of the Weighted Regressions on Time, Discharge, and Season regression models to provide accurate representations of flux, showed acceptable bias (less than ±10 percent) for 68 out of 72 models for total and dissolved phosphorus, total nitrogen, and chloride. Six out of 18 models for total suspended solids had moderate bias (between 10 and 30 percent), an expected result given the frequently nonlinear relation between total suspended solids and discharge. One model for total suspended solids with a very high bias was influenced by a single extreme value; however, removal of that value, although reducing the bias substantially, had little effect on annual fluxes.

Potential efficiencies of open- and closed-cycle CO, supersonic, electric-discharge lasers

NASA Technical Reports Server (NTRS)

Monson, D. J.

1976-01-01

Computed open- and closed-cycle system efficiencies (laser power output divided by electrical power input) are presented for a CW carbon monoxide, supersonic, electric-discharge laser. Closed-system results include the compressor power required to overcome stagnation pressure losses due to supersonic heat addition and a supersonic diffuser. The paper shows the effect on the system efficiencies of varying several important parameters. These parameters include: gas mixture, gas temperature, gas total temperature, gas density, total discharge energy loading, discharge efficiency, saturated gain coefficient, optical cavity size and location with respect to the discharge, and supersonic diffuser efficiency. Maximum open-cycle efficiency of 80-90% is predicted; the best closed-cycle result is 60-70%.

Differential distribution of voltage-gated channels in myelinated and unmyelinated baroreceptor afferents.

PubMed

Schild, John H; Kunze, Diana L

2012-12-24

Voltage gated ion channels (VGC) make possible the frequency coding of arterial pressure and the neurotransmission of this information along myelinated and unmyelinated fiber pathways. Although many of the same VGC isoforms are expressed in both fiber types, it is the relative expression of each that defines the unique discharge properties of myelinated A-type and unmyelinated C-type baroreceptors. For example, the fast inward Na⁺ current is a major determinant of the action potential threshold and the regenerative transmembrane current needed to sustain repetitive discharge. In A-type baroreceptors the TTX-sensitive Na(v)1.7 VGC contributes to the whole cell Na⁺ current. Na(v)1.7 is expressed at a lower density in C-type neurons and in conjunction with TTX-insensitive Na(v)1.8 and Na(v)1.9 VGC. As a result, action potentials of A-type neurons have firing thresholds that are 15-20 mV more negative and upstroke velocities that are 5-10 times faster than unmyelinated C-type neurons. A more depolarized threshold in conjunction with a broader complement of non-inactivating K(V) VGC subtypes produces C-type action potentials that are 3-4 times longer in duration than A-type neurons and at markedly lower levels of cell excitability. Unmyelinated baroreceptors also express KCa1.1 which provides approximately 25% of the total outward K⁺ current. KCa1.1 plays a critically important role in shaping the action potential profile of C-type neurons and strongly impacts neuronal excitability. A-type neurons do not functionally express the KCa1.1 channel despite having a whole cell Ca(V) current quite similar to that of C-type neurons. As a result, A-type neurons do not have the frequency-dependent braking forces of KCa1.1. Lack of a KCa current and only a limited complement of non-inactivating K(V) VGC in addition to a hyperpolarization activated HCN1 current that is nearly 10 times larger than in C-type neurons leads to elevated levels of discharge in A-type neurons, a hallmark of myelinated baroreceptors. Interestingly, HCN2 and HCN4 expression levels are comparable in both fiber types. Collectively, such apportion of VGC constrains the neural coding of myelinated A-type baroreceptors to low threshold, high frequency, high fidelity discharge but with a limited capacity for neuromodulation of afferent bandwidth. Unmyelinated C-type baroreceptors require greater depolarizing forces for spike initiation and have a low frequency discharge profile that is often poorly correlated with the physiological stimulus. But the complement of VGC in C-type neurons provides far greater capacity for neuromodulation of cell excitability than can be obtained from A-type baroreceptors. Copyright © 2012 Elsevier B.V. All rights reserved.

Hypogonadism on admission to acute rehabilitation is correlated with lower functional status at admission and discharge.

PubMed

Carlson, N E; Brenner, L A; Wierman, M E; Harrison-Felix, C; Morey, C; Gallagher, S; Ripley, D

2009-04-01

To investigate the association between hormone levels and functional status during acute TBI rehabilitation. Retrospective cohort study of 43 men with moderate-to-severe TBI admitted to an acute rehabilitation unit during a 1 year period. Labs were drawn on admission, including total and free testosterone (T), prolactin, adrenocorticotropin hormone (ACTH), cortisol, thyroid stimulating hormone (TSH), free thyroxine (fT4) and insulin-like growth factor (IGF-1). Functional Independence Measure (FIM) scores were obtained at admission and discharge. Associations between admission hormone levels and the main outcomes, admission and discharge FIM scores, were assessed using linear regression. Lower total and free T-levels at admission were associated with lower total FIM scores at admission (p < 0.038) and discharge (p < 0.046). Higher cortisol levels at admission were significantly associated with lower admission (p = 0.012) and discharge (p = 0.036) scores on the cognitive-FIM. Prolactin, TSH, fT4 and IGF-1 were not correlated with functional status. In men, lower total and free T-levels at admission to acute rehabilitation correlate with lower admission and discharge FIM scores. These data support the need for studies to investigate the impact of physiological testosterone therapy on outcomes during and post-rehabilitation.

Association of the Ottawa Aggressive Protocol with rapid discharge of emergency department patients with recent-onset atrial fibrillation or flutter.

PubMed

Stiell, Ian G; Clement, Catherine M; Perry, Jeffrey J; Vaillancourt, Christian; Symington, Cheryl; Dickinson, Garth; Birnie, David; Green, Martin S

2010-05-01

There is no consensus on the optimal management of recent-onset episodes of atrial fibrillation or flutter. The approach to these conditions is particularly relevant in the current era of emergency department (ED) overcrowding. We sought to examine the effectiveness and safety of the Ottawa Aggressive Protocol to perform rapid cardioversion and discharge patients with these arrhythmias. This cohort study enrolled consecutive patient visits to an adult university hospital ED for recent-onset atrial fibrillation or flutter managed with the Ottawa Aggressive Protocol. The protocol includes intravenous chemical cardioversion, electrical cardioversion if necessary and discharge home from the ED. A total of 660 patient visits were included, 95.2% involving atrial fibrillation and 4.9% involving atrial flutter. The mean age of patients enrolled was 64.5 years. In total, 96.8% were discharged home and, of those, 93.3% were in sinus rhythm. All patients were initially administered intravenous procainamide, with a 58.3% conversion rate. A total of 243 patients underwent subsequent electrical cardioversion with a 91.7% success rate. Adverse events occurred in 7.6% of cases: hypotension 6.7%, bradycardia 0.3% and 7-day relapse 8.6%. There were no cases of torsades de pointes, stroke or death. The median lengths of stay in the ED were as follows: 4.9 hours overall, 3.9 hours for those undergoing conversion with procainamide and 6.5 hours for those requiring electrical conversion. This is the largest study to date to evaluate the Ottawa Aggressive Protocol, a unique approach to cardioversion for ED patients with recent-onset episodes of atrial fibrillation and flutter. Our data demonstrate that the Ottawa Aggressive Protocol is effective, safe and rapid, and has the potential to significantly reduce hospital admissions and expedite ED care.

Performance, Stability, and Plume Characterization of the HERMeS Thruster with Boron Nitride Silica Composite Discharge Channel

NASA Technical Reports Server (NTRS)

Kamhawi, Hani; Huang, Wensheng; Gilland, James H.; Haag, Thomas W.; Mackey, Jonathan; Yim, John; Pinero, Luis; Williams, George; Peterson, Peter; Herman, Daniel

2017-01-01

NASA's Hall Effect Rocket with Magnetic Shielding (HERMeS) 12.5kW Technology Demonstration Unit-3 (TDU-3) has been the subject of extensive technology maturation in preparation for flight system development. Detailed performance, stability, and plume characterization tests of the thruster were performed at NASA GRC's Vacuum Facility 5 (VF-5). The TDU-3 thruster implements a magnetic topology that is identical to TDU-1. The TDU-3 boron nitride silica composite discharge channel material is different than the TDU-1 heritage boron nitride discharge channel material. Performance and stability characterization of the TDU-3 thruster was performed at discharge voltages between 300V and 600V and at discharge currents between 5A and 21.8A. The thruster performance and stability were assessed for varying magnetic field strength, cathode flow fractions between 5% and 9%, varying harness inductance, and for reverse magnet polarity. Performance characterization test results indicate that the TDU-3 thruster performance is in family with the TDU-1 levels. TDU-3's thrust efficiency of 65% and specific impulse of 2,800sec at 600V and 12.5kW exceed performance levels of SOA Hall thrusters. Thruster stability regimes were characterized with respect to the thruster discharge current oscillations (discharge current peak-to-peak and root mean square magnitudes), discharge current waveform power spectral density analysis, and maps of the current-voltage-magnetic field. Stability characterization test results indicate a stability profile similar to TDU-1. Finally, comparison of the TDU-1 and TDU-3 plume profiles found that there were negligible differences in the plasma plume characteristics between the TDU with heritage boron nitride versus the boron nitride silica composite discharge channel.

A comparative study on the frequency effects of the electrical characteristics of the pulsed dielectric barrier discharge in He/O{sub 2} and in Ar/O{sub 2} at atmospheric pressure

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

Pan, Guangsheng; Tan, Zhenyu, E-mail: tzy@sdu.edu.cn; Pan, Jie

In this work, a comparative study on the frequency effects of the electrical characteristics of the pulsed dielectric barrier discharges in He/O{sub 2} and in Ar/O{sub 2} at atmospheric pressure has been performed by means of the numerical simulation based on a 1-D fluid model at frequencies below 100 kHz. The frequency dependences of the characteristic quantities of the discharges in the two gases have been systematically calculated and analyzed under the oxygen concentrations below 2%. The characteristic quantities include the discharge current density, the averaged electron density, the electric field, and the averaged electron temperature. Especially, the frequency effects onmore » the averaged particle densities of the reactive species have also been calculated. This work gives the following significant results. For the two gases, there are two bipolar discharges in one period of applied voltage pulse under the considered frequency range and oxygen concentrations, as occurred in the pure noble gases. The frequency affects the two discharges in He/O{sub 2}, but in Ar/O{sub 2}, it induces a strong effect only on the first discharge. For the first discharge in each gas, there is a characteristic frequency at which the characteristic quantities reach their respective minimum, and this frequency appears earlier for Ar/O{sub 2}. For the second discharge in Ar/O{sub 2}, the averaged electron density presents a slight variation with the frequency. In addition, the discharge in Ar/O{sub 2} is strong and the averaged electron temperature is low, compared to those in He/O{sub 2.} The total averaged particle density of the reactive species in Ar/O{sub 2} is larger than those in He/O{sub 2} by about one order of magnitude.« less

Disposition of elderly patients after head and neck reconstruction.

PubMed

Hatcher, Jeanne L; Bell, Elizabeth Bradford; Browne, J Dale; Waltonen, Joshua D

2013-11-01

A patient's needs at discharge, particularly the need for nursing facility placement, may affect hospital length of stay and health care costs. The association between age and disposition after microvascular reconstruction of the head and neck has yet to be reported in the literature. To determine whether elderly patients are more likely to be discharged to a nursing or other care facility as opposed to returning home after microvascular reconstruction of the head and neck. From January 1, 2001, through December 31, 2010, patients undergoing microvascular reconstruction at an academic medical center were identified and their medical records systematically reviewed. During the study period, 457 patients were identified by Current Procedural Terminology codes for microvascular free tissue transfer for a head and neck defect regardless of cause. Seven patients were excluded for inadequate data on the postoperative disposition or American Society of Anesthesiologists (ASA) score. A total of 450 were included for analysis. Demographic and surgical data were collected, including the patient age, ASA score, and postoperative length of stay. These variables were then compared between groups of patients discharged to different posthospitalization care facilities. The mean age of participants was 59.1 years. Most patients (n = 386 [85.8%]) were discharged home with or without home health services. The mean age of those discharged home was 57.5 years; discharge to home was the reference for comparison and odds ratio (OR) calculation. For those discharged to a skilled nursing facility, mean age was 67.1 years (OR, 1.055; P < .001). Mean age of those discharged to a long-term acute care facility was 71.5 years (OR, 1.092; P = .002). Length of stay also affected the disposition to a skilled nursing facility (OR, 1.098), as did the ASA score (OR, 2.988). Elderly patients are less likely to be discharged home after free flap reconstruction. Age, ASA score, and length of stay are independent factors for discharge to a nursing or other care facility.

Wind tunnel experiments on flow separation control of an Unmanned Air Vehicle by nanosecond discharge plasma aerodynamic actuation

NASA Astrophysics Data System (ADS)

Kang, Chen; Hua, Liang

2016-02-01

Plasma flow control (PFC) is a new kind of active flow control technology, which can improve the aerodynamic performances of aircrafts remarkably. The flow separation control of an unmanned air vehicle (UAV) by nanosecond discharge plasma aerodynamic actuation (NDPAA) is investigated experimentally in this paper. Experimental results show that the applied voltages for both the nanosecond discharge and the millisecond discharge are nearly the same, but the current for nanosecond discharge (30 A) is much bigger than that for millisecond discharge (0.1 A). The flow field induced by the NDPAA is similar to a shock wave upward, and has a maximal velocity of less than 0.5 m/s. Fast heating effect for nanosecond discharge induces shock waves in the quiescent air. The lasting time of the shock waves is about 80 μs and its spread velocity is nearly 380 m/s. By using the NDPAA, the flow separation on the suction side of the UAV can be totally suppressed and the critical stall angle of attack increases from 20° to 27° with a maximal lift coefficient increment of 11.24%. The flow separation can be suppressed when the discharge voltage is larger than the threshold value, and the optimum operation frequency for the NDPAA is the one which makes the Strouhal number equal one. The NDPAA is more effective than the millisecond discharge plasma aerodynamic actuation (MDPAA) in boundary layer flow control. The main mechanism for nanosecond discharge is shock effect. Shock effect is more effective in flow control than momentum effect in high speed flow control. Project supported by the National Natural Science Foundation of China (Grant Nos. 61503302, 51207169, and 51276197), the China Postdoctoral Science Foundation (Grant No. 2014M562446), and the Natural Science Foundation of Shaanxi Province, China (Grant No. 2015JM1001).

Simulation of the effect of an oil refining project on the water environment using the MIKE 21 model

NASA Astrophysics Data System (ADS)

Jia, Peng; Wang, Qinggai; Lu, Xuchuan; Zhang, Beibei; Li, Chen; Li, Sa; Li, Shibei; Wang, Yaping

2018-02-01

A case study of the Caofeidian oil refining project is conducted. A two-dimensional convective dispersion mathematical model is established to simulate the increase in the concentration of pollutants resulting from the wastewater discharge from the Caofeidian oil refining project and to analyze the characteristics of the dispersion of pollutants after wastewater is discharged and the effect of the wastewater discharge on the surrounding sea areas. The results demonstrate the following: (1) The Caofeidian sea area has strong tidal currents, which are significantly affected by the terrain. There are significant differences in the tidal current velocity and the direction between the deep-water areas and the shoals. The direction of the tidal currents in the deep-water areas is essentially parallel to the contour lines of the sea areas. Onshore currents and rip currents submerging the shoals are the dominant currents in the shoals. (2) The pollutant concentration field in the offshore areas changes periodically with the movement of the tidal current. The dilution and dispersion of pollutants are affected by the ocean currents in different tidal periods. The turbulent dispersion of pollutants is the most intense when a neap tide ebbs, followed by when a neap tide rises, when a spring tide ebbs and when a spring tide rises. (3) There are relatively good hydrodynamic conditions near the project's wastewater discharge outlet. Wastewater is well diluted after being discharged. Areas with high concentrations of pollutants are concentrated near the wastewater discharge outlet and the offshore areas. These pollutants migrate southwestward with the flood tidal current and northeastward with the ebb tidal current and have no significant impact on the protection targets in the open sea areas and nearby sea areas.

Negative DC corona discharge current characteristics in a flowing two-phase (air + suspended smoke particles) fluid

NASA Astrophysics Data System (ADS)

Berendt, Artur; Domaszka, Magdalena; Mizeraczyk, Jerzy

2017-04-01

The electrical characteristics of a steady-state negative DC corona discharge in a two-phase fluid (air with suspended cigarette smoke particles) flowing along a chamber with a needle-to-plate electrode arrangement were experimentally investigated. The two-phase flow was transverse in respect to the needle-to-plate axis. The velocity of the transverse two-phase flow was limited to 0.8 m/s, typical of the electrostatic precipitators. We found that three discharge current modes of the negative corona exist in the two-phase (air + smoke particles) fluid: the Trichel pulses mode, the "Trichel pulses superimposed on DC component" mode and the DC component mode, similarly as in the corona discharge in air (a single-phase fluid). The shape of Trichel pulses in the air + suspended particles fluid is similar to that in air. However, the Trichel pulse amplitudes are higher than those in "pure" air while their repetition frequency is lower. As a net consequence of that the averaged corona discharge current in the two-phase fluid is lower than in "pure" air. It was also found that the average discharge current decreases with increasing suspended particle concentration. The calculations showed that the dependence of the average negative corona current (which is a macroscopic corona discharge parameter) on the particle concentration can be explained by the particle-concentration dependencies of the electric charge of Trichel pulse and the repetition frequency of Trichel pulses, both giving a microscopic insight into the electrical phenomena in the negative corona discharge. Our investigations showed also that the average corona discharge current in the two-phase fluid is almost unaffected by the transverse fluid flow up to a velocity of 0.8 m/s. Contribution to the topical issue "The 15th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XV)", edited by Nicolas Gherardi and Tomáš Hoder

Production of Nitrogen Oxides by Laboratory Simulated Transient Luminous Events

NASA Astrophysics Data System (ADS)

Peterson, H.; Bailey, M.; Hallett, J.; Beasley, W.

2007-12-01

Restoration of the polar stratospheric ozone layer has occurred at rates below those originally expected following reductions in chlorofluorocarbon (CFC) usage. Additional reactions affecting ozone depletion now must also be considered. This research examines nitrogen oxides (NOx) produced in the middle atmosphere by transient luminous events (TLEs), with NOx production in this layer contributing to the loss of stratospheric ozone. In particular, NOx produced by sprites in the mesosphere would be transported to the polar stratosphere via the global meridional circulation and downward diffusion. A pressure-controlled vacuum chamber was used to simulate middle atmosphere pressures, while a power supply and in-chamber electrodes were used to simulate TLEs in the pressure controlled environment. Chemiluminescence NOx analyzers were used to sample NOx produced by the chamber discharges- originally a Monitor Labs Model 8440E, later a Thermo Environment Model 42. Total NOx production for each discharge as well as NOx per ampere of current and NOx per Joule of discharge energy were plotted. Absolute NOx production was greatest for discharge environments with upper tropospheric pressures (100-380 torr), while NOx/J was greatest for discharge environments with stratospheric pressures (around 10 torr). The different production efficiencies in NOx/J as a function of pressure pointed to three different production regimes, each with its own reaction mechanisms: one for tropospheric pressures, one for stratospheric pressures, and one for upper stratospheric to mesospheric pressures (no greater than 1 torr).

Total direct cost, length of hospital stay, institutional discharges and their determinants from rehabilitation settings in stroke patients.

PubMed

Saxena, S K; Ng, T P; Yong, D; Fong, N P; Gerald, K

2006-11-01

Length of hospital stay (LOHS) is the largest determinant of direct cost for stroke care. Institutional discharges (acute care and nursing homes) from rehabilitation settings add to the direct cost. It is important to identify potentially preventable medical and non-medical reasons determining LOHS and institutional discharges to reduce the direct cost of stroke care. The aim of the study was to ascertain the total direct cost, LOHS, frequency of institutional discharges and their determinants from rehabilitation settings. Observational study was conducted on 200 stroke patients in two rehabilitation settings. The patients were examined for various socio-demographic, neurological and clinical variables upon admission to the rehabilitation hospitals. Information on total direct cost and medical complications during hospitalization were also recorded. The outcome variables measured were total direct cost, LOHS and discharges to institutions (acute care and nursing home facility) and their determinants. The mean and median LOHS in our study were 34 days (SD = 18) and 32 days respectively. LOHS and the cost of hospital stay were significantly correlated. The significant variables associated with LOHS on multiple linear regression analysis were: (i) severe functional impairment/functional dependence Barthel Index < or = 50, (ii) medical complications, (iii) first time stroke, (iv) unplanned discharges and (v) discharges to nursing homes. Of the stroke patients 19.5% had institutional discharges (22 to acute care and 17 to nursing homes). On multivariate analysis the significant predictors of discharges to institutions from rehabilitation hospitals were medical complications (OR = 4.37; 95% CI 1.01-12.53) and severe functional impairment/functional dependence. (OR = 5.90, 95% CI 2.32-14.98). Length of hospital stay and discharges to institutions from rehabilitation settings are significantly determined by medical complications. Importance of adhering to clinical pathway/protocol for stroke care is further discussed.

A composition analyzer for microparticles using a spark ion source. [using time of flight spectrometers

NASA Technical Reports Server (NTRS)

Auer, S. O.; Berg, O. E.

1975-01-01

Iron microparticles were fired onto a capacitor-type microparticle detector which responded to an impact with a spark discharge. Ion currents were extracted from the spark and analyzed in a time-of-flight mass spectrometer. The mass spectra showed the element of both detector and particle materials. The total extracted ion currents was typically 10A within a period of 100ns, indicating very efficient vaporization of the particle and ionization of the vapor. Potential applications include research on cosmic dust, atmospheric aerosols and cloud droplets, particles ejected by rocket or jet engines, by machining processes, or by nuclear bomb explosions.

Study on residual discharge time of lead-acid battery based on fitting method

NASA Astrophysics Data System (ADS)

Liu, Bing; Yu, Wangwang; Jin, Yueqiang; Wang, Shuying

2017-05-01

This paper use the method of fitting to discuss the data of C problem of mathematical modeling in 2016, the residual discharge time model of lead-acid battery with 20A,30A,…,100A constant current discharge is obtained, and the discharge time model of discharge under arbitrary constant current is presented. The mean relative error of the model is calculated to be about 3%, which shows that the model has high accuracy. This model can provide a basis for optimizing the adaptation of power system to the electrical motor vehicle.

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.

Discharge measurements at gaging stations

USGS Publications Warehouse

Turnipseed, D. Phil; Sauer, Vernon B.

2010-01-01

The techniques and standards for making discharge measurements at streamflow gaging stations are described in this publication. The vertical axis rotating-element current meter, principally the Price current meter, has been traditionally used for most measurements of discharge; however, advancements in acoustic technology have led to important developments in the use of acoustic Doppler current profilers, acoustic Doppler velocimeters, and other emerging technologies for the measurement of discharge. These new instruments, based on acoustic Doppler theory, have the advantage of no moving parts, and in the case of the acoustic Doppler current profiler, quickly and easily provide three-dimensional stream-velocity profile data through much of the vertical water column. For much of the discussion of acoustic Doppler current profiler moving-boat methodology, the reader is referred to U.S. Geological Survey Techniques and Methods 3-A22 (Mueller and Wagner, 2009). Personal digital assistants (PDAs), electronic field notebooks, and other personal computers provide fast and efficient data-collection methods that are more error-free than traditional hand methods. The use of portable weirs and flumes, floats, volumetric tanks, indirect methods, and tracers in measuring discharge are briefly described.

Optogalvanic effect and laser-induced current oscillations in hollow-cathode lamps

NASA Astrophysics Data System (ADS)

Eldakli, Mohsan S. A.; Ivković, Saša S.; Obradović, Bratislav M.

2017-03-01

This paper presents a study of two commercial hollow-cathode lamps (HCLs) with the intention of demonstrating different phenomena in gas discharges. The optogalvanic effect in both HCLs is produced by a laser diode radiated at the wavelength that corresponds to neon transition 1s2-2p2 at 659.89 nm. The voltage-current characteristics of the lamps are explained using a classical theory of hollow-cathode discharge, while the optogalvanic signal is treated as a small perturbation of the discharge current. For certain values of voltage self-sustained current oscillations are observed in one of the HCLs. In the same HCL laser-induced optogalvanic dumped oscillations are detected. A phenomenological model that includes the effective circuit parameters of the discharge is used to explain the oscillation characteristics.

An Experimental Visualization and Image Analysis of Electrohydrodynamically Induced Vapor-Phase Silicon Oil Flow under DC Corona Discharge

NASA Astrophysics Data System (ADS)

Ohyama, Ryu-Ichiro; Fukumoto, Masaru

A DC corona discharge induced electrohydrodynamic (EHD) flow phenomenon for a multi-phase fluid containing a vapor-phase dielectric liquid in the fresh air was investigated. The experimental electrode system was a simple arrangement of needle-plate electrodes for the corona discharges and high-resistivity silicon oil was used as the vapor-phase liquid enclosure. The qualitative observation of EHD flow patterns was conducted by an optical processing on computer tomography and the time-series of discharge current pulse generations at corona discharge electrode were measured simultaneously. These experimental results were analyzed in relationship between the EHD flow motions and the current pulse generations in synchronization. The current pulses and the EHD flow motions from the corona discharge electrode presented a continuous mode similar to the ionic wind in the fresh air and an intermittent mode. In the intermittent mode, the observed EHD flow motion was synchronized with the separated discharge pulse generations. From these experimental results, it was expected that the existence of silicon oil vapor trapped charges gave an occasion to the intermittent generations of the discharge pulses and the secondary EHD flow.

Estimating Discharge, Depth and Bottom Friction in Sand Bed Rivers Using Surface Currents and Water Surface Elevation Observations

NASA Astrophysics Data System (ADS)

Simeonov, J.; Czapiga, M. J.; Holland, K. T.

2017-12-01

We developed an inversion model for river bathymetry estimation using measurements of surface currents, water surface elevation slope and shoreline position. The inversion scheme is based on explicit velocity-depth and velocity-slope relationships derived from the along-channel momentum balance and mass conservation. The velocity-depth relationship requires the discharge value to quantitatively relate the depth to the measured velocity field. The ratio of the discharge and the bottom friction enter as a coefficient in the velocity-slope relationship and is determined by minimizing the difference between the predicted and the measured streamwise variation of the total head. Completing the inversion requires an estimate of the bulk friction, which in the case of sand bed rivers is a strong function of the size of dune bedforms. We explored the accuracy of existing and new empirical closures that relate the bulk roughness to parameters such as the median grain size diameter, ratio of shear velocity to sediment fall velocity or the Froude number. For given roughness parameterization, the inversion solution is determined iteratively since the hydraulic roughness depends on the unknown depth. We first test the new hydraulic roughness parameterization using estimates of the Manning roughness in sand bed rivers based on field measurements. The coupled inversion and roughness model is then tested using in situ and remote sensing measurements of the Kootenai River east of Bonners Ferry, ID.

Characteristics of radio-frequency atmospheric pressure dielectric-barrier discharge with dielectric electrodes

NASA Astrophysics Data System (ADS)

Hussain, S.; Qazi, H. I. A.; Badar, M. A.

2014-03-01

An experimental investigation to characterize the properties and highlight the benefits of atmospheric pressure radio-frequency dielectric-barrier discharge (rf DBD) with dielectric electrodes fabricated by anodizing aluminium substrate is presented. The current-voltage characteristics and millisecond images are used to distinguish the α and γ modes. This atmospheric rf DBD is observed to retain the discharge volume without constriction in γ mode. Optical emission spectroscopy demonstrates that the large discharge current leads to more abundant reactive species in this plasma source.

Breakdown in helium in high-voltage open discharge with subnanosecond current front rise

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

Schweigert, I. V., E-mail: ischweig@itam.nsc.ru; Alexandrov, A. L.; Bokhan, P. A.

Investigations of high-voltage open discharge in helium have shown a possibility of generation of current pulses with subnanosecond front rise, due to ultra-fast breakdown development. The open discharge is ignited between two planar cathodes with mesh anode in the middle between them. For gas pressure 6 Torr and 20 kV applied voltage, the rate of current rise reaches 500 A/(cm{sup 2} ns) for current density 200 A/cm{sup 2} and more. The time of breakdown development was measured for different helium pressures and a kinetic model of breakdown in open discharge is presented, based on elementary reactions for electrons, ions andmore » fast atoms. The model also includes various cathode emission processes due to cathode bombardment by ions, fast atoms, electrons and photons of resonant radiation with Doppler shift of frequency. It is shown, that the dominating emission processes depend on the evolution of the discharge voltage during the breakdown. In the simulations, two cases of voltage behavior were considered: (i) the voltage is kept constant during the breakdown; (ii) the voltage is reduced with the growth of current. For the first case, the exponentially growing current is maintained due to photoemission by the resonant photons with Doppler-shifted frequency. For the second case, the dominating factor of current growth is the secondary electron emission. In both cases, the subnanosecond rise of discharge current was obtained. Also the effect of gas pressure on breakdown development was considered. It was found that for 20 Torr gas pressure the time of current rise decreases to 0.1 ns, which is in agreement with experimental data.« less

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.

Positive direct current corona discharges in single wire-duct electrostatic precipitators

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, Arab Republic of Egypt; Abdel-Fattah, E.

This paper is aimed to study the characteristics of the positive dc corona discharges in single wire-duct electrostatic precipitators. Therefore, the corona discharges were formed inside dry air fed single wire-duct reactor under positive dc voltage at the normal atmospheric conditions. The corona current-voltage characteristics curves have been measured in parallel with the ozone concentration generated inside the reactor under different discharge conditions. The corona current-voltage characteristics curves have agreed with a semi empirical equation derived from the previous studies. The experimental results of the ozone concentration generated inside the reactor were formulated in the form of an empirical equationmore » included the different parameters that were studied experimentally. The obtained equations are valid to expect both the current-voltage characteristics curves and the corresponding ozone concentration that generates with the positive dc corona discharges inside single wire-duct electrostatic precipitators under any operating conditions in the same range of the present study.« less

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

Advanced electrical current measurements of microdischarges: evidence of sub-critical pulses and ion currents in barrier discharge in air

NASA Astrophysics Data System (ADS)

Synek, Petr; Zemánek, Miroslav; Kudrle, Vít; Hoder, Tomáš

2018-04-01

Electrical current measurements in corona or barrier microdischarges are a challenge as they require both high temporal resolution and a large dynamic range of the current probe used. In this article, we apply a simple self-assembled current probe and compare it to commercial ones. An analysis in the time and frequency domain is carried out. Moreover, an improved methodology is presented, enabling both temporal resolution in sub-nanosecond times and current sensitivity in the order of tens of micro-amperes. Combining this methodology with a high-tech oscilloscope and self-developed software, a unique statistical analysis of currents in volume barrier discharge driven in atmospheric-pressure air is made for over 80 consecutive periods of a 15 kHz applied voltage. We reveal the presence of repetitive sub-critical current pulses and conclude that these can be identified with the discharging of surface charge microdomains. Moreover, extremely low, long-lasting microsecond currents were detected which are caused by ion flow, and are analysed in detail. The statistical behaviour presented gives deeper insight into the discharge physics of these usually undetectable current signals.

Integrating preconcentrator heat controller

DOEpatents

Bouchier, Francis A.; Arakaki, Lester H.; Varley, Eric S.

2007-10-16

A method and apparatus for controlling the electric resistance heating of a metallic chemical preconcentrator screen, for example, used in portable trace explosives detectors. The length of the heating time-period is automatically adjusted to compensate for any changes in the voltage driving the heating current across the screen, for example, due to gradual discharge or aging of a battery. The total deposited energy in the screen is proportional to the integral over time of the square of the voltage drop across the screen. Since the net temperature rise, .DELTA.T.sub.s, of the screen, from beginning to end of the heating pulse, is proportional to the total amount of heat energy deposited in the screen during the heating pulse, then this integral can be calculated in real-time and used to terminate the heating current when a pre-set target value has been reached; thereby providing a consistent and reliable screen temperature rise, .DELTA.T.sub.s, from pulse-to-pulse.

High energy density asymmetric supercapacitors with a nickel oxide nanoflake cathode and a 3D reduced graphene oxide anode

NASA Astrophysics Data System (ADS)

Luan, Feng; Wang, Gongming; Ling, Yichuan; Lu, Xihong; Wang, Hanyu; Tong, Yexiang; Liu, Xiao-Xia; Li, Yat

2013-08-01

Here we demonstrate a high energy density asymmetric supercapacitor with nickel oxide nanoflake arrays as the cathode and reduced graphene oxide as the anode. Nickel oxide nanoflake arrays were synthesized on a flexible carbon cloth substrate using a seed-mediated hydrothermal method. The reduced graphene oxide sheets were deposited on three-dimensional (3D) nickel foam by hydrothermal treatment of nickel foam in graphene oxide solution. The nanostructured electrodes provide a large effective surface area. The asymmetric supercapacitor device operates with a voltage of 1.7 V and achieved a remarkable areal capacitance of 248 mF cm-2 (specific capacitance of 50 F g-1) at a charge/discharge current density of 1 mA cm-2 and a maximum energy density of 39.9 W h kg-1 (based on the total mass of active materials of 5.0 mg). Furthermore, the device showed an excellent charge/discharge cycling performance in 1.0 M KOH electrolyte at a current density of 5 mA cm-2, with a capacitance retention of 95% after 3000 cycles.

FORTE Compact Intra-cloud Discharge Detection parameterized by Peak Current

NASA Astrophysics Data System (ADS)

Heavner, M. J.; Suszcynsky, D. M.; Jacobson, A. R.; Heavner, B. D.; Smith, D. A.

2002-12-01

The Los Alamos Sferic Array (EDOT) has recorded over 3.7 million lightning-related fast electric field change data records during April 1 - August 31, 2001 and 2002. The events were detected by three or more stations, allowing for differential-time-of-arrival location determination. The waveforms are characterized with estimated peak currents as well as by event type. Narrow Bipolar Events (NBEs), the VLF/LF signature of Compact Intra-cloud Discharges (CIDs), are generally isolated pulses with identifiable ionospheric reflections, permitting determination of event source altitudes. We briefly review the EDOT characterization of events. The FORTE satellite observes Trans-Ionospheric Pulse Pairs (TIPPs, the VHF satellite signature of CIDs). The subset of coincident EDOT and FORTE CID observations are compared with the total EDOT CID database to characterize the VHF detection efficiency of CIDs. The NBE polarity and altitude are also examined in the context of FORTE TIPP detection. The parameter-dependent detection efficiencies are extrapolated from FORTE orbit to GPS orbit in support of the V-GLASS effort (GPS based global detection of lightning).

High energy density asymmetric supercapacitors with a nickel oxide nanoflake cathode and a 3D reduced graphene oxide anode.

PubMed

Luan, Feng; Wang, Gongming; Ling, Yichuan; Lu, Xihong; Wang, Hanyu; Tong, Yexiang; Liu, Xiao-Xia; Li, Yat

2013-09-07

Here we demonstrate a high energy density asymmetric supercapacitor with nickel oxide nanoflake arrays as the cathode and reduced graphene oxide as the anode. Nickel oxide nanoflake arrays were synthesized on a flexible carbon cloth substrate using a seed-mediated hydrothermal method. The reduced graphene oxide sheets were deposited on three-dimensional (3D) nickel foam by hydrothermal treatment of nickel foam in graphene oxide solution. The nanostructured electrodes provide a large effective surface area. The asymmetric supercapacitor device operates with a voltage of 1.7 V and achieved a remarkable areal capacitance of 248 mF cm(-2) (specific capacitance of 50 F g(-1)) at a charge/discharge current density of 1 mA cm(-2) and a maximum energy density of 39.9 W h kg(-1) (based on the total mass of active materials of 5.0 mg). Furthermore, the device showed an excellent charge/discharge cycling performance in 1.0 M KOH electrolyte at a current density of 5 mA cm(-2), with a capacitance retention of 95% after 3000 cycles.

The impact of social isolation on delayed hospital discharges of older hip fracture patients and associated costs.

PubMed

Landeiro, F; Leal, J; Gray, A M

2016-02-01

Delayed discharges represent an inefficient use of acute hospital beds. Social isolation and referral to a public-funded rehabilitation unit were significant predictors of delayed discharges while admission from an institution was a protective factor for older hip fracture patients. Preventing delays could save between 11.2 and 30.7 % of total hospital costs for this patient group. Delayed discharges of older patients from acute care hospitals are a major challenge for administrative, humanitarian, and economic reasons. At the same time, older people are particularly vulnerable to social isolation which has a detrimental effect on their health and well-being with cost implications for health and social care services. The purpose of the present study was to determine the impact and costs of social isolation on delayed hospital discharge. A prospective study of 278 consecutive patients aged 75 or older with hip fracture admitted, as an emergency, to the Orthopaedics Department of Hospital Universitário de Santa Maria, Portugal, was conducted. A logistic regression model was used to examine the impact of relevant covariates on delayed discharges, and a negative binomial regression model was used to examine the main drivers of days of delayed discharges. Costs of delayed discharges were estimated using unit costs from national databases. Mean age at admission was 85.5 years and mean length of stay was 13.1 days per patient. Sixty-two (22.3 %) patients had delayed discharges, resulting in 419 bed days lost (11.5 % of the total length of stay). Being isolated or at a high risk of social isolation, measured with the Lubben social network scale, was significantly associated with delayed discharges (odds ratio (OR) 3.5) as was being referred to a public-funded rehabilitation unit (OR 7.6). These two variables also increased the number of days of delayed discharges (2.6 and 4.9 extra days, respectively, holding all else constant). Patients who were admitted from an institution were less likely to have delayed discharges (OR 0.2) with 5.5 fewer days of delay. Total costs of delayed discharges were between 11.2 and 30.7 % of total costs (€2352 and €9317 per patient with delayed discharge) conditional on whether waiting costs for placement in public-funded rehabilitation unit were included. High risk of social isolation, social isolation and referral to public-funded rehabilitation units increase delays in patients' discharges from acute care hospitals.

Generation of uniform low-temperature plasma in a pulsed non-self-sustained glow discharge with a large-area hollow cathode

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

Akhmadeev, Yu. H.; Denisov, V. V., E-mail: volodyadenisov@yandex.ru; Koval, N. N.

Generation of plasma in a pulsed non-self-sustained glow discharge with a hollow cathode with an area of ≥2 m{sup 2} at gas pressures of 0.4–1 Pa was studied experimentally. At an auxiliary arc-discharge current of 100 A and a main discharge voltage of 240 V, a pulse-periodic glow discharge with a current amplitude of 370 A, pulse duration of 340 μs, and repetition rate of 1 kHz was obtained. The possibility of creating a uniform gas-discharge plasma with a density of up to 10{sup 12} cm{sup −3} and an electron temperature of 1 eV in a volume of >0.2 m{supmore » 3} was demonstrated. Such plasma can be efficiently used to treat material surfaces and generate pulsed ion beams with a current density of up to 15 mA/cm{sup 2}.« less

Formation of Ion Beam from High Density Plasma of ECR Discharge

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

Izotov, I.; Razin, S.; Sidorov, A.

2005-03-15

One of the most promising directions of ECR multicharged ion sources evolution is related with increase in frequency of microwave pumping. During last years microwave generators of millimeter wave range - gyrotrons have been used more frequently. Creation of plasma with density 1013 cm-3 with medium charged ions and ion flux density through a plug of a magnetic trap along magnetic field lines on level of a few A/cm2 is possible under pumping by powerful millimeter wave radiation and quasigasdynamic (collisional) regime of plasma confinement in the magnetic trap. Such plasma has great prospects for application in plasma based ionmore » implantation systems for processing of surfaces with complicated and petit relief. Use it for ion beam formation seams to be difficult because of too high ion current density. This paper continues investigations described elsewhere and shows possibility to arrange ion extraction in zone of plasma expansion from the magnetic trap along axis of system and magnetic field lines.Plasma was created at ECR gas discharge by means of millimeter wave radiation of a gyrotron with frequency 37.5 GHz, maximum power 100 kW, pulse duration 1.5 ms. Two and three electrode quasi-Pierce extraction systems were used for ion beam formation.It is demonstrated that there is no changes in ion charge state distribution along expansion routing of plasma under collisional confinement. Also ion flux density decreases with distance from plug of the trap, it allows to control extracting ion current density. Multicharged ion beam of Nitrogen with total current up to 2.5 mA at diameter of extracting hole 1 mm, that corresponds current density 320 mA/cm2, was obtained. Magnitude of total ion current was limited due to extracting voltage (60 kV). Under such conditions characteristic transversal dimension of plasma equaled 4 cm, magnetic field value in extracting zone was about 0.1 T at axisymmetrical configuration.« less

Influences of rainfall variables and antecedent discharge on urban effluent concentrations and loads in wet weather.

PubMed

Xu, Zuxin; Xiong, Lijun; Li, Huaizheng; Liao, Zhengliang; Yin, Hailong; Wu, Jun; Xu, Jin; Chen, Hao

2017-04-01

For storm drainages inappropriately connected with sewage, wet weather discharge is a major factor that adversely affects receiving waters. A study of the wet weather influences of rainfall-discharge variables on storm drainages connected with sewage was conducted in the downtown Shanghai area (374 ha). Two indicators, event mean concentration (EMC) and event pollutant load per unit area (EPL), were used to describe the pollution discharge during 20 rain events. The study showed that the total rainfall and discharge volume were important factors that affect the EMCs and EPLs of the chemical oxygen demand, total phosphorus, and especially those of NH 4 + -N. The pollutant concentrations at the beginning of the discharge and the discharge period were also major factors that influence the EMCs of these three pollutants. Regression relationships between the rainfall-discharge variables and discharge volume/ EPLs (R 2 = 0.824-0.981) were stronger than the relationships between the rainfall-discharge variables and EMCs. These regression equations can be considered reliable in the system, with a relative validation error of less than ±10% for the discharge volume, and less than ±20% for the EPLs. The results presented in this paper provide guidance for effectively controlling pollution in similar storm drainages.

Outpatient rehabilitation care process factors and clinical outcomes among patients discharged home following unilateral total knee arthroplasty.

PubMed

Brennan, Gerard P; Fritz, Julie M; Houck, L T C Kevin M; Hunter, Stephen J

2015-05-01

Research examining care process variables and their relationship to clinical outcomes after total knee arthroplasty has focused primarily on inpatient variables. Care process factors related to outpatient rehabilitation have not been adequately examined. We conducted a retrospective review of 321 patients evaluating outpatient care process variables including use of continuous passive motion, home health physical therapy, number of days from inpatient discharge to beginning outpatient physical therapy, and aspects of outpatient physical therapy (number of visits, length of stay) as possible predictors of pain and disability outcomes of outpatient physical therapy. Only the number of days between inpatient discharge and outpatient physical therapy predicted better outcomes, suggesting that this may be a target for improving outcomes after total knee arthroplasty for patients discharged directly home. Copyright © 2014 Elsevier Inc. All rights reserved.

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.

Effect of adrenaline on survival in out-of-hospital cardiac arrest: A randomised double-blind placebo-controlled trial.

PubMed

Jacobs, Ian G; Finn, Judith C; Jelinek, George A; Oxer, Harry F; Thompson, Peter L

2011-09-01

There is little evidence from clinical trials that the use of adrenaline (epinephrine) in treating cardiac arrest improves survival, despite adrenaline being considered standard of care for many decades. The aim of our study was to determine the effect of adrenaline on patient survival to hospital discharge in out of hospital cardiac arrest. We conducted a double blind randomised placebo-controlled trial of adrenaline in out-of-hospital cardiac arrest. Identical study vials containing either adrenaline 1:1000 or placebo (sodium chloride 0.9%) were prepared. Patients were randomly allocated to receive 1 ml aliquots of the trial drug according to current advanced life support guidelines. Outcomes assessed included survival to hospital discharge (primary outcome), pre-hospital return of spontaneous circulation (ROSC) and neurological outcome (Cerebral Performance Category Score - CPC). A total of 4103 cardiac arrests were screened during the study period of which 601 underwent randomisation. Documentation was available for a total of 534 patients: 262 in the placebo group and 272 in the adrenaline group. Groups were well matched for baseline characteristics including age, gender and receiving bystander CPR. ROSC occurred in 22 (8.4%) of patients receiving placebo and 64 (23.5%) who received adrenaline (OR=3.4; 95% CI 2.0-5.6). Survival to hospital discharge occurred in 5 (1.9%) and 11 (4.0%) patients receiving placebo or adrenaline respectively (OR=2.2; 95% CI 0.7-6.3). All but two patients (both in the adrenaline group) had a CPC score of 1-2. Patients receiving adrenaline during cardiac arrest had no statistically significant improvement in the primary outcome of survival to hospital discharge although there was a significantly improved likelihood of achieving ROSC. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Wastewater reuse in liquid sodium silicate manufacturing in alexandria, egypt.

PubMed

Ismail, Gaber A; Abd El-Salam, Magda M; Arafa, Anwar K

2009-01-01

Soluble sodium silicates (waterglass) are liquids containing dissolved glass which have some water like properties. They are widely used in industry as sealants, binders, deflocculants, emulsifiers and buffers. Their most common applications in Egypt are in the pulp and paper industry (where they improve the brightness and efficiency of peroxide bleaching) and the detergent industry, in which they improve the action of the detergent and lower the viscosity of liquid soaps. The survey results showed that the production was carried out batch-wise, in an autoclave (dissolver). Sodium silicate in the state of crushed glass was charged in an autoclave (dissolver) with sodium hydroxide and water. The product is filtered through a press. The left over sludge (mud and silicates impurities) is emptied into the local sewer system. Also, sludge (silica gel) was discharged from the neutralization process of the generated alkaline wastewater and consequently clogging the sewerage system. So this study was carried out to modify the current wastewater management system which eliminates sludge formation, the discharge of higher pH wastewater to the sewer system, and to assess its environmental and economic benefits. To assess the characteristics of wastewater to be reused, physico-chemical parameters of 12 samples were tested using standard methods. The survey results showed that a total capacity of the selected enterprise was 540 tons of liquid sodium silicates monthly. The total amount of wastewater being discharged was 335 m3/month. Reusing of wastewater as feed autoclave water reduced water consumption of 32.1% and reduced wastewater discharge/month that constitutes 89.6% as well as saving in final product of 6 ton/month. It was concluded that reusing of wastewater generated from liquid sodium silicate manufacturing process resulted in cheaper and environmental-friendly product.

Specific features of a single-pulse sliding discharge in neon near the threshold for spark breakdown

NASA Astrophysics Data System (ADS)

Trusov, K. K.

2017-08-01

Experimental data on the spatial structure of a single-pulse sliding discharge in neon at voltages below, equal to, and above the threshold for spark breakdown are discussed. The experiments were carried at gas pressures of 30 and 100 kPa and different polarities of the discharge voltage. Photographs of the plasma structure in two discharge chambers with different dimensions of the discharge zone and different thicknesses of an alumina dielectric plate on the surface of which the discharge develops are inspected. Common features of the prebreakdown discharge and its specific features depending on the voltage polarity and gas pressure are analyzed. It is shown that, at voltages below the threshold for spark breakdown, a low-current glow discharge with cathode and anode spots develops in the electrode gap. Above the breakdown threshold, regardless of the voltage polarity, spark channels directed from the cathode to the anode develop against the background of a low-current discharge.

Temporal Variations in Distributions of NO and NO2 Densities in Streamer Corona Discharges

NASA Astrophysics Data System (ADS)

Kurakane, Hiroshi; Aramaki, Mitsutoshi; Sasaki, Koichi

2006-10-01

The distributions of NO and NO2 densities were measured in high-pressure streamer corona discharges by laser-induced fluorescence imaging spectroscopy at various delay times after applying pulsed high voltages between needle and planar electrodes. It was found that the decrease in NO2 density in an N2/O2/NO2 discharge was more efficient than that in an N2/NO2 discharge. The dominant removal reaction of NO2 from the N2/O2/NO2 discharge was NO2+O→NO+O2. The importance of this reaction has been confirmed by the simultaneous observation of the distributions of the NO and NO2 densities. The total amount of NO2 removed from the N2/O2/NO2 discharge roughly coincided with the total amount of NO observed at the same delay time.

Kinetic interpretation of resonance phenomena in low pressure capacitively coupled radio frequency plasmas

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

Wilczek, Sebastian; Trieschmann, Jan; Eremin, Denis

Low pressure capacitive radio frequency (RF) plasmas are often described by equivalent circuit models based on fluid approaches that predict the self-excitation of resonances, e.g., high frequency oscillations of the total current in asymmetric discharges, but do not provide a kinetic interpretation of these effects. In fact, they leave important questions open: How is current continuity ensured in the presence of energetic electron beams generated by the expanding sheaths that lead to a local enhancement of the conduction current propagating through the bulk? How do the beam electrons interact with cold bulk electrons? What is the kinetic origin of resonancemore » phenomena? Based on kinetic simulations, we find that the energetic beam electrons interact with cold bulk electrons (modulated on a timescale of the inverse local electron plasma frequency) via a time dependent electric field outside the sheaths. This electric field is caused by the electron beam itself, which leaves behind a positive space charge, that attracts cold bulk electrons towards the expanding sheath. The resulting displacement current ensures current continuity by locally compensating the enhancement of the conduction current. The backflow of cold electrons and their interaction with the nonlinear plasma sheath cause the generation of multiple electron beams during one phase of sheath expansion and contribute to a strongly non-sinusoidal RF current. These kinetic mechanisms are the basis for a fundamental understanding of the electron power absorption dynamics and resonance phenomena in such plasmas, which are found to occur in discharges of different symmetries including perfectly symmetric plasmas.« less

Test Results of a Ten Cell Bipolar Nickel-hydrogen Battery

NASA Technical Reports Server (NTRS)

Cataldo, R. L.

1984-01-01

A study was initiated to design and evaluate a new design concept for nickel-hydrogen cells. This concept involved constructing a battery in a bipolar stack with cells consisting of a one plate for each nickel and hydrogen electrode. Preliminary designs at the system level of this concept promised improvements in both volumetric and gravimetric energy densities, thermal management, life extension, costs, and peak power capability over more conventional designs. Test results were most encouraging. This preprototype battery, built with less than ideal components and hardware, exceeded expectations. A total of 2000 LEO cycles at 80 percent depth of discharge were accrued. A cycle life goal of 30,000 cycles appears achievable with minor design changes. These improvements include advanced technology nickel electrodes, insulated bipolar plates and specifically designed frames to minimize shunt currents. The discharge rate capability of this design exceeds 25C. At the 10C discharge rate, 80% of the battery capacity can be withdrawn in six minutes. This data shows that the bipolar design is well suited for those applications requiring high peak power pulses.

Conceptual Design of the Nuclear Electronic Xenon Ion System (NEXIS)

NASA Technical Reports Server (NTRS)

Monheiser, Jeff; Polk, Jay; Randolph, Tom

2004-01-01

In support of the NEXIS program, Aerojet-Redmond Operations, with review and input from the JPL and Boeing, has completed the design for a development model (DM) discharge chamber assembly and main discharge cathode assembly. These efforts along with the work by JPL to develop the carbon-carbon-composite ion optics assembly have resulted in a complete ion engine design. The goal of the NEXIS program is to significantly advance the current state of the art by developing an ion engine capable of operating at an input power of 20kW, an Isp of 7500 sec and have a total xenon through put capability of 2000 kg. In this paper we will describe the methodology used to design the discharge chamber and cathode assemblies and describe the resulting final design. Specifics will include the concepts used for the mounting of the ion optics along with the concepts used for the gimbal mounts. In addition, we will present results of a vibrational analysis showing how the engine will respond to a typical Delta IV heavy vibration spectrum.

A Simple Analytical Model for Predicting the Detectable Ion Current in Ion Mobility Spectrometry Using Corona Discharge Ionization Sources

NASA Astrophysics Data System (ADS)

Kirk, Ansgar Thomas; Kobelt, Tim; Spehlbrink, Hauke; Zimmermann, Stefan

2018-05-01

Corona discharge ionization sources are often used in ion mobility spectrometers (IMS) when a non-radioactive ion source with high ion currents is required. Typically, the corona discharge is followed by a reaction region where analyte ions are formed from the reactant ions. In this work, we present a simple yet sufficiently accurate model for predicting the ion current available at the end of this reaction region when operating at reduced pressure as in High Kinetic Energy Ion Mobility Spectrometers (HiKE-IMS) or most IMS-MS instruments. It yields excellent qualitative agreement with measurement results and is even able to calculate the ion current within an error of 15%. Additional interesting findings of this model are the ion current at the end of the reaction region being independent from the ion current generated by the corona discharge and the ion current in High Kinetic Energy Ion Mobility Spectrometers (HiKE-IMS) growing quadratically when scaling down the length of the reaction region. [Figure not available: see fulltext.

A Simple Analytical Model for Predicting the Detectable Ion Current in Ion Mobility Spectrometry Using Corona Discharge Ionization Sources.

PubMed

Kirk, Ansgar Thomas; Kobelt, Tim; Spehlbrink, Hauke; Zimmermann, Stefan

2018-05-08

Corona discharge ionization sources are often used in ion mobility spectrometers (IMS) when a non-radioactive ion source with high ion currents is required. Typically, the corona discharge is followed by a reaction region where analyte ions are formed from the reactant ions. In this work, we present a simple yet sufficiently accurate model for predicting the ion current available at the end of this reaction region when operating at reduced pressure as in High Kinetic Energy Ion Mobility Spectrometers (HiKE-IMS) or most IMS-MS instruments. It yields excellent qualitative agreement with measurement results and is even able to calculate the ion current within an error of 15%. Additional interesting findings of this model are the ion current at the end of the reaction region being independent from the ion current generated by the corona discharge and the ion current in High Kinetic Energy Ion Mobility Spectrometers (HiKE-IMS) growing quadratically when scaling down the length of the reaction region. Graphical Abstract ᅟ.

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.

Influence of the electrode gap separation on the pseudospark-sourced electron beam generation

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

Zhao, J., E-mail: junping.zhao@qq.com; State Key Laboratory of Electrical Insulation and Power Equipment, West Xianning Road, Xi'an 710049; Department of Physics, SUPA, University of Strathclyde, Glasgow, G4 0NG Scotland

Pseudospark-sourced electron beam is a self-focused intense electron beam which can propagate without any external focusing magnetic field. This electron beam can drive a beam-wave interaction directly or after being post-accelerated. It is especially suitable for terahertz radiation generation due to the ability of a pseudospark discharge to produce small size in the micron range and very high current density and bright electron beams. In this paper, a single-gap pseudospark discharge chamber has been built and tested with several electrode gap separations to explore the dependence of the pseudospark-sourced electron beam current on the discharge voltage and the electrode gapmore » separation. Experimental results show that the beam pulses have similar pulse width and delay time from the distinct drop of the applied voltage for smaller electrode gap separations but longer delay time for the largest gap separation used in the experiment. It has been found that the electron beam only starts to occur when the charging voltage is above a certain value, which is defined as the starting voltage of the electron beam. The starting voltage is different for different electrode gap separations and decreases with increasing electrode gap separation in our pseudospark discharge configuration. The electron beam current increases with the increasing discharge voltage following two tendencies. Under the same discharge voltage, the configuration with the larger electrode gap separation will generate higher electron beam current. When the discharge voltage is higher than 10 kV, the beam current generated at the electrode gap separation of 17.0 mm, is much higher than that generated at smaller gap separations. The ionization of the neutral gas in the main gap is inferred to contribute more to the current increase with increasing electrode gap separation.« less

Removal of a hydrogenated amorphous carbon film from the tip of a micropipette electrode using direct current corona discharge.

PubMed

Kakuta, Naoto; Okuyama, Naoki; Yamada, Yukio

2010-02-01

Micropipette electrodes are fabricated by coating glass micropipettes first with metal and then with hydrogenated amorphous carbon (a-C:H) as an electrical insulator. Furthermore, at the tip of the micropipette electrode, the deposited a-C:H film needs to be removed to expose the metal-coated surface and hollow for the purposes of electrical measurement and injection. This paper describes a convenient and reliable method for removing the a-C:H film using direct current corona discharge in atmospheric air. The initial film removal occurred at an applied voltage of 1.5-2.0 kV, accompanied by an abrupt increase in the discharge current. The discharge current then became stable at a microampere level in the glow corona mode, and the removed area gradually extended.

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 persists. However, nonlinear, voltage-dependent, capacitance of the double layer is responsible for a break in temporal antisymmetry of the charging and discharging currents. Third, the reverse peak in the discharging current develops in a "strongly nonlinear" regime V ≳VTln(1 /ɛ ) , driven by neutral salt adsorption into the double layers and consequent bulk depletion during charging. The strongly nonlinear regime features current evolution over three timescales. The current decays in magnitude on the double layer relaxation timescale, λD2/D ; then grows exponentially in time towards the reverse peak on the diffusion timescale, L2/D , indicating that the reverse peak is the results of fast diffusion of ions from the double layer layer to the bulk. Following the reverse peak, the current decays exponentially to zero on the R C timescale. Notably, the current at the reverse peak and the time of the reverse peak saturate at large voltages V ≫VTln(1 /ɛ ) . We provide semi-analytic expressions for the saturated reverse peak time and current, which can be used to infer charge carrier diffusivity and concentration from experiments.

Provisional Coding Practices: Are They Really a Waste of Time?

PubMed

Krypuy, Matthew; McCormack, Lena

2006-11-01

In order to facilitate effective clinical coding and hence the precise financial reimbursement of acute services, in 2005 Western District Health Service (WDHS) (located in regional Victoria, Australia) undertook a provisional coding trial for inpatient medical episodes to determine the magnitude and accuracy of clinical documentation. Utilising clinical coding software installed on a laptop computer, provisional coding was undertaken for all current overnight inpatient episodes under each physician one day prior to attending their daily ward round. The provisionally coded episodes were re-coded upon the completion of the discharge summary and the final Diagnostic Related Group (DRG) allocation and weight were compared to the provisional DRG assignment. A total of 54 out of 220 inpatient medical episodes were provisionally coded. This represented approximately a 25% cross section of the population selected for observation. Approximately 67.6% of the provisionally allocated DRGs were accurate in contrast to 32.4% which were subject to change once the discharge summary was completed. The DRG changes were primarily due to: disease progression of a patient during their care episode which could not be identified by clinical coding staff due to discharge prior to the following scheduled ward round; the discharge destination of particular patients; and the accuracy of clinical documentation on the discharge summary. The information gathered from the provisional coding trial supported the hypothesis that clinical documentation standards were sufficient and adequate to support precise clinical coding and DRG assignment at WDHS. The trial further highlighted the importance of a complete and accurate discharge summary available during the coding process of acute inpatient episodes.

Integrated environmental monitoring and multivariate data analysis-A case study.

PubMed

Eide, Ingvar; Westad, Frank; Nilssen, Ingunn; de Freitas, Felipe Sales; Dos Santos, Natalia Gomes; Dos Santos, Francisco; Cabral, Marcelo Montenegro; Bicego, Marcia Caruso; Figueira, Rubens; Johnsen, Ståle

2017-03-01

The present article describes integration of environmental monitoring and discharge data and interpretation using multivariate statistics, principal component analysis (PCA), and partial least squares (PLS) regression. The monitoring was carried out at the Peregrino oil field off the coast of Brazil. One sensor platform and 3 sediment traps were placed on the seabed. The sensors measured current speed and direction, turbidity, temperature, and conductivity. The sediment trap samples were used to determine suspended particulate matter that was characterized with respect to a number of chemical parameters (26 alkanes, 16 PAHs, N, C, calcium carbonate, and Ba). Data on discharges of drill cuttings and water-based drilling fluid were provided on a daily basis. The monitoring was carried out during 7 campaigns from June 2010 to October 2012, each lasting 2 to 3 months due to the capacity of the sediment traps. The data from the campaigns were preprocessed, combined, and interpreted using multivariate statistics. No systematic difference could be observed between campaigns or traps despite the fact that the first campaign was carried out before drilling, and 1 of 3 sediment traps was located in an area not expected to be influenced by the discharges. There was a strong covariation between suspended particulate matter and total N and organic C suggesting that the majority of the sediment samples had a natural and biogenic origin. Furthermore, the multivariate regression showed no correlation between discharges of drill cuttings and sediment trap or turbidity data taking current speed and direction into consideration. Because of this lack of correlation with discharges from the drilling location, a more detailed evaluation of chemical indicators providing information about origin was carried out in addition to numerical modeling of dispersion and deposition. The chemical indicators and the modeling of dispersion and deposition support the conclusions from the multivariate statistics. Integr Environ Assess Manag 2017;13:387-395. © 2016 SETAC. © 2016 SETAC.

Evaluating the impact of irrigation on surface water - groundwater interaction and stream temperature in an agricultural watershed.

PubMed

Essaid, Hedeff I; Caldwell, Rodney R

2017-12-01

Changes in groundwater discharge to streams caused by irrigation practices can influence stream temperature. Observations along two currently flood-irrigated reaches in the 640-square-kilometer upper Smith River watershed, an important agricultural and recreational fishing area in west-central Montana, showed a downstream temperature decrease resulting from groundwater discharge to the stream. A watershed-scale coupled surface water and groundwater flow model was used to examine changes in streamflow, groundwater discharge to the stream and stream temperature resulting from irrigation practices. The upper Smith River watershed was used to develop the model framework including watershed climate, topography, hydrography, vegetation, soil properties and current irrigation practices. Model results were used to compare watershed streamflow, groundwater recharge, and groundwater discharge to the stream for three scenarios: natural, pre-irrigation conditions (PreIrr); current irrigation practices involving mainly stream diversion for flood and sprinkler irrigation (IrrCurrent); and a hypothetical scenario with only groundwater supplying sprinkler irrigation (IrrGW). Irrigation increased groundwater recharge relative to natural PreIrr conditions because not all applied water was removed by crop evapotranspiration. Groundwater storage and groundwater discharge to the stream increased relative to natural PreIrr conditions when the source of irrigation water was mainly stream diversion as in the IrrCurrent scenario. The hypothetical IrrGW scenario, in which groundwater withdrawals were the sole source of irrigation water, resulted in widespread lowering of the water table and associated decreases in groundwater storage and groundwater discharge to the stream. A mixing analysis using model predicted groundwater discharge along the reaches suggests that stream diversion and flood irrigation, represented in the IrrCurrent scenario, has led to cooling of stream temperatures relative to natural PreIrr conditions improving fish thermal habitat. However, the decrease in groundwater discharge in the IrrGW scenario resulting from large-scale groundwater withdrawal for irrigation led to warmer than natural stream temperatures and possible degradation of fish habitat. Published by Elsevier B.V.

Heating and cooling of the multiply charged ion nonequilibrium plasma in a high-current extended low-inductance discharge

NASA Astrophysics Data System (ADS)

Burtsev, V. A.; Kalinin, N. V.

2014-09-01

Using a radiation magnetohydrodynamics two-temperature model (RMHD model) of a high-current volumetric radiating Z-discharge, the heating and cooling of the nitrogen plasma in a pulsed pinched extended discharge is investigated as applied to the problem of creating a recombination laser based on 3 → 2 transitions of hydrogen-like nitrogen ions (λ = 13.4 nm). It is shown that the power supply of the discharge, which is represented by a dual storage-forming line and a transmission line, makes it possible to raise the power density of the nitrogen plasma to 0.01-1.00 TW/cm3. Accordingly, there arises the possibility of generating a fully ionized (i.e., consisting of bare nuclei and electrons) plasma through the heating (compression) of electrons owing to the self-magnetic field of the plasma current and Joule heat even if the plasma is cooled by its own radiation at this stage. Such a plasma is needed to produce the lasing (active) medium of a recombination laser based on electron transitions in hydrogen-like ions. At the second stage, it is necessary to rapidly and deeply cool the plasma to 20-40 eV for 1-2 ns. Cooling of the fully ionized expanding plasma was numerically simulated with the discharge current switched on and off by means of a switch with a rapidly rising resistance. In both cases, the plasma expansion in the discharge is not adiabatic. Even after the discharge current is fairly rapidly switched off, heating of electrons continues inside the plasma column for a time longer than the switching time. Discharge current switchoff improves the electron cooling efficiency only slightly. Under such conditions, the plasma cools down to 50-60 eV in the former case and to 46-54 eV in the latter case for 2-3 ns.

Evaluating the impact of irrigation on surface water – groundwater interaction and stream temperature in an agricultural watershed

USGS Publications Warehouse

Essaid, Hedeff I.; Caldwell, Rodney R.

2017-01-01

Changes in groundwater discharge to streams caused by irrigation practices can influence stream temperature. Observations along two currently flood-irrigated reaches in the 640-square-kilometer upper Smith River watershed, an important agricultural and recreational fishing area in west-central Montana, showed a downstream temperature decrease resulting from groundwater discharge to the stream. A watershed-scale coupled surface water and groundwater flow model was used to examine changes in streamflow, groundwater discharge to the stream and stream temperature resulting from irrigation practices. The upper Smith River watershed was used to develop the model framework including watershed climate, topography, hydrography, vegetation, soil properties and current irrigation practices. Model results were used to compare watershed streamflow, groundwater recharge, and groundwater discharge to the stream for three scenarios: natural, pre-irrigation conditions (PreIrr); current irrigation practices involving mainly stream diversion for flood and sprinkler irrigation (IrrCurrent); and a hypothetical scenario with only groundwater supplying sprinkler irrigation (IrrGW). Irrigation increased groundwater recharge relative to natural PreIrr conditions because not all applied water was removed by crop evapotranspiration. Groundwater storage and groundwater discharge to the stream increased relative to natural PreIrr conditions when the source of irrigation water was mainly stream diversion as in the IrrCurrent scenario. The hypothetical IrrGW scenario, in which groundwater withdrawals were the sole source of irrigation water, resulted in widespread lowering of the water table and associated decreases in groundwater storage and groundwater discharge to the stream. A mixing analysis using model predicted groundwater discharge along the reaches suggests that stream diversion and flood irrigation, represented in the IrrCurrent scenario, has led to cooling of stream temperatures relative to natural PreIrr conditions improving fish thermal habitat. However, the decrease in groundwater discharge in the IrrGW scenario resulting from large-scale groundwater withdrawal for irrigation led to warmer than natural stream temperatures and possible degradation of fish habitat.

Post-discharge compliance to venous thromboembolism prophylaxis in high-risk orthopaedic surgery: results from the ETHOS registry.

PubMed

Bergqvist, David; Arcelus, Juan I; Felicissimo, Paulo

2012-02-01

Venous thromboembolism (VTE) risk persists for several weeks following high-risk orthopaedic surgery (HROS). The ETHOS registry evaluated post-operative VTE prophylaxis prescribed, and actual VTE prophylaxis received, compared with the 2004 American College of Chest Physicians (ACCP) guidelines in HROS patients. We performed a subanalysis of ETHOS to assess patient compliance with ACCP-adherent prophylaxis after discharge and the factors predicting poor compliance. Consecutive patients undergoing hip fracture surgery, total hip arthroplasty, or knee arthroplasty were enrolled at discharge from 161 centres in 17 European countries if they had received adequate in-hospital VTE prophylaxis. Data on prescribed and actual prophylaxis received were obtained from hospital charts and patient post-discharge diaries. Good compliance was defined as percentage treatment intake ≥80% with no more than two consecutive days without treatment. A total of 3,484 patients (79.4%) received ACCP-adherent anticoagulant prescription at discharge and 2,999 (86.0%) had an evaluable patient diary. In total, 87.7% of evaluable patients were compliant with prescribed treatment after discharge. The most common reason for non-compliance (33.4%) was "drug was not bought". Injection of treatment was not a barrier to good compliance. Main factors affecting compliance related to purchase of and access to treatment, patient education, the person responsible for administering injections, country, and type of hospital ward at discharge. Within our study population, patient compliance with ACCP-adherent thromboprophylaxis prescribed at discharge was good. Improvements in patient education and prescribing practices at discharge may be important in further raising compliance levels in high-risk orthopaedic surgery patients.

Sediment Transport in the Lower Yampa River, Northwestern Colorado

USGS Publications Warehouse

Elliott, John G.; Kircher, James E.; Von Guerard, Paul

1984-01-01

Discharge measurements and sediment samples were taken at streamflow-gaging station 09260050 Yampa River at Deerlodge Park in 1982 and 1983 to determine the annual sediment supply to the Yampa Canyon in Dinosaur National Monument. Forty-three years of discharge records at two tributary sites were combined to determine the historic discharge of the Yampa River at Deerlodge Park. A mean annual hydrograph and flow-duration curve were derived from these data. Sediment-transport equations were derived for total sediment discharge, suspended-sediment discharge, bedload dischagre, and the discharge of sediment in several particle-sizes. Annual sediment discharge were determined by the flow-duration, sediment-rating-curve method and indicated annual total sediment discharge was approximately 2.0 million tons per year of which 0.8 million tons per year was sand-sized material. Bedload was almost entirely sand, and annual bedload discharge was 0.1 million tons per year. Development of water resources in the Yampa River basin could effect the geomorphic character of the Yampa River at Deerlodge Park and the Yampa Canyon. Several scenarios of altered streamflow frequency distribution, reduced streamflow volume, and reduced sediment supply are examined to estimate the effect on the sediment budget at Deerlodge Park. (USGS)

Solenoid-free plasma startup in NSTX using transient CHI

NASA Astrophysics Data System (ADS)

Raman, R.; Jarboe, T. R.; Mueller, D.; Nelson, B. A.; Bell, M. G.; Bell, R.; Gates, D.; Gerhardt, S.; Hosea, J.; Kaita, R.; Kugel, H.; LeBlanc, B.; Maingi, R.; Maqueda, R.; Menard, J.; Nagata, M.; Ono, M.; Paul, S.; Roquemore, L.; Sabbagh, S.; Soukhanovskii, V.; Taylor, G.

2009-06-01

Experiments in NSTX have now demonstrated the coupling of toroidal plasmas produced by the technique of coaxial helicity injection (CHI) to inductive sustainment and ramp-up of the toroidal plasma current. In these discharges, the central Ohmic transformer was used to apply an inductive loop voltage to discharges with a toroidal current of about 100 kA created by CHI. The coupled discharges have ramped up to >700 kA and transitioned into an H-mode demonstrating compatibility of this startup method with conventional operation. The electron temperature in the coupled discharges reached over 800 eV and the resulting plasma had low inductance, which is preferred for long-pulse high-performance discharges. These results from NSTX in combination with the previously obtained record 160 kA non-inductively generated startup currents in an ST or tokamak in NSTX demonstrate that CHI is a viable solenoid-free plasma startup method for future STs and tokamaks.

Temporal variation of transit time of rainfall-runoff water and groundwater flow dynamics inferred by noble gasses concentration (SF6, CFCs) in a forested small catchment (Fukushima, Japan)

NASA Astrophysics Data System (ADS)

Sakakibara, Koichi; Tsujimura, Maki; Onda, Yuichi; Iwagami, Sho; Konuma, Ryohei; Sato, Yutaro

2016-04-01

Time variant transit time of water in catchments can fundamentally describe catchment function, controlling rainfall-runoff generation, groundwater flow pathway and water storage. Though rainstorm event has been recognized as active phase on catchment hydrology, accurate and precise time variance of water transit time and related water dynamics during rainstorm have not been well clarified yet. Here, in order to reveal temporal variation of mean transit time of groundwater and related hydrological processes in a forested small catchment during rainstorm event, periodic and intensive field observations (15 - 17th July 2015, rainfall of 100.8 mm in total) were conducted in Yamakiya district (Fukushima, Japan) from September 2014 to December 2015. Discharge volume, groundwater table and precipitation amount were measured in 10 minutes interval. Water samples were taken from groundwater, discharge water, soil water and precipitation for determination of stable isotopic compositions (δ18O, δ2H), inorganic solutes concentration and dissolved noble gasses concentration (CFC11, CFC12, CFC113, SF6) in water. Storm hydrograph and groundwater table clearly responded to rainfall event especially with more than 30 mm per day throughout monitoring period. According to SF6 concentration in water, the mean transit time of discharge water (perennial spring) showed 3 - 6.5 years in the no-rainfall period (steady state), but fluctuated from zero to 12.5 years in the rainstorm event with totally 100.8 mm (unsteady state). The mean transit time of discharge water dramatically altered from zero to 12.5 years from before to after the tentative hydrograph peak in the rising limb, indicating new water components were dominant before tentative hydrograph peak, whereas deep groundwater component with longer residence time contributed much to discharge after the tentative hydrograph peak. On the other hand, mean residence time of groundwater (water in 5 m well) ranged from 0.5 to 11.5 years during the rainstorm event, which followed temporal transit time variation of discharge water. Stable isotopic compositions and chloride ions as conservative tracers presented clear different signals between rainfall and discharge water, and chloride ion concentration in discharge water increased to as high as deeper groundwater (water in 20 m well) just after tentative hydrograph peak in the rising limb. Additionally, CFCs concentration especially in discharge water obviously decreased below the level of current atmospheric CFCs concentration. All of the facts suggest that the contribution of deep groundwater with longer residence time for the discharge water becomes significant at the jumping phase of runoff during intense rainfall, causing dynamic change of groundwater flow system in a catchment.

Discharge current distribution in stratified soil under impulse discharge

NASA Astrophysics Data System (ADS)

Eniola Fajingbesi, Fawwaz; Shahida Midi, Nur; Elsheikh, Elsheikh M. A.; Hajar Yusoff, Siti

2017-06-01

The mobility of charge particles traversing a material defines its electrical properties. Soil (earth) have long been the universal grounding before and after the inception of active ground systems for electrical appliance purpose due to it semi-conductive properties. The soil can thus be modelled as a single material exhibiting semi-complex inductive-reactive impedance. Under impulse discharge such as lightning strikes to soil this property of soil could result in electric potential level fluctuation ranging from ground potential rise/fall to electromagnetic pulse coupling that could ultimately fail connected electrical appliance. In this work we have experimentally model the soil and lightning discharge using point to plane electrode setup to observe the current distribution characteristics at different soil conductivity [mS/m] range. The result presented from this research indicate above 5% shift in conductivity before and after discharge which is significant for consideration when dealing with grounding designs. The current distribution in soil have also be successfully observed and analysed from experimental result using mean current magnitude in relation to electrode distance and location, current density variation with depth all showing strong correlation with theoretical assumptions of a semi-complex impedance material.

Dimensionless factors for an alternating-current non-thermal arc plasma

NASA Astrophysics Data System (ADS)

Zhang, Si-Yuan; Li, Xiao-Song; Liu, Jin-Bao; Liu, Jing-Lin; Li, He-Ping; Zhu, Ai-Min

2016-12-01

A gliding arc discharge, as a source of warm plasma combining advantages of both thermal and cold plasmas, would have promising application prospects in the fields of fuel conversion, combustion enhancement, material synthesis, surface modifications, pollution control, etc. In order to gain insight into the features of an alternating-current gliding arc discharge plasma, three dimensionless factors, i.e., the extinction span (ψ), current lag (δ), and heating lag (χ) factors are proposed in this letter based on the measured waveforms of the discharge voltage and current in an AC gliding arc discharge plasma. The influences of the driving frequency of the power supply (f) on these three dimensionless parameters are investigated experimentally with the explanations on the physical meanings of these factors. The experimental results show that a higher value of f would lead to the lower values of ψ and δ, as well as a higher value of χ. These experimental phenomena indicate a lower threshold ignition voltage of the discharges, a lower current-growth inertia of the gliding arcs and a larger relative thermal inertia of the plasmas with increase the driving frequency of the power supply in the operating parameter range studied in this letter.

Neutralization of an ion beam from the end-Hall ion source by a plasma electron source based on a discharge in crossed E × H fields

NASA Astrophysics Data System (ADS)

Dostanko, A. P.; Golosov, D. A.

2009-10-01

The possibility of using a plasma electron source (PES) with a discharge in crossed E × H field for compensating the ion beam from an end-Hall ion source (EHIS) is analyzed. The PES used as a neutralizer is mounted in the immediate vicinity of the EHIS ion generation and acceleration region at 90° to the source axis. The behavior of the discharge and emission parameters of the EHIS is determined for operation with a filament neutralizer and a plasma electron source. It is found that the maximal discharge current from the ion source attains a value of 3.8 A for operation with a PES and 4 A for operation with a filament compensator. It is established that the maximal discharge current for the ion source strongly depends on the working gas flow rate for low flow rates (up to 10 ml/min) in the EHIS; for higher flow rates, the maximum discharge current in the EHIS depends only on the emissivity of the PES. Analysis of the emission parameters of EHISs with filament and plasma neutralizers shows that the ion beam current and the ion current density distribution profile are independent of the type of the electron source and the ion current density can be as high as 0.2 mA/cm2 at a distance of 25 cm from the EHIS anode. The balance of currents in the ion source-electron source system is considered on the basis of analysis of operation of EHISs with various sources of electrons. It is concluded that the neutralization current required for operation of an ion source in the discharge compensation mode must be equal to or larger than the discharge current of the ion source. The use of PES for compensating the ion beam from an end-Hall ion source proved to be effective in processes of ion-assisted deposition of thin films using reactive gases like O2 or N2. The application of the PES technique makes it possible to increase the lifetime of the ion-assisted deposition system by an order of magnitude (the lifetime with a Ti cathode is at least 60 h and is limited by the replacement life of the deposited cathode insertion).

Early discharge after total thyroidectomy: a retrospective feasibility study.

PubMed

Tartaglia, F; Giuliani, A; Sorrenti, S; Tromba, L; Carbotta, S; Maturo, A; Carbotta, G; De Anna, L; Merola, R; Livadoti, G; Pelle, F; Ulisse, S

2016-01-01

The continued hospitalization after total thyroidectomy is often due to the onset of hypocalcemic complications more than 24 hours after surgery. So it would be important to predict which patients will not develop the hypocalcemic complication to discharge them early. This was the aim of our study. Our retrospective study was conducted on 327 consecutive thyroidectomized patients, operated on for benign and malignant diseases. We evaluated the values of preoperative serum calcium levels (Cal0) and of the first postoperative day (Cal1) and two new variables were calculated (dCal and dCaln). The same thing was made on a subgroup of 111 patients in whom also parathiroyd hormone (PTH) values were detected. Statistical analysis was performed with the goal of determining if we could establish a safe criterion for discharge at 24 hours after surgery and if there is a correlation between suitability for discharge and diagnosis. As to discharge, the predictive power of the discriminant function applied was significant both on the total of patients and in the subgroup of 111 patients, but it was clinically unacceptable because it would expose us to a 21% to 27% error rate. It is not possible to identify a threshold, below which to consider patients surely dischargeable. The diagnosis does not appear correlated with the suitability for discharge. On the basis of serum calcium and PTH levels in the first postoperative day, it is impossible to predict which patients can be discharged 24 hours after surgery without incurring in hypocalcemic complications.

Alternating current corona discharge/atmospheric pressure chemical ionization for mass spectrometry.

PubMed

Habib, Ahsan; Usmanov, Dilshadbek; Ninomiya, Satoshi; Chen, Lee Chuin; Hiraoka, Kenzo

2013-12-30

Although alternating current (ac) corona discharge has been widely used in the fields of material science and technology, no reports have been published on its application to an atmospheric pressure chemical ionization (APCI) ion source. In this work, ac corona discharge for an APCI ion source has been examined for the first time. The ambient atmospheric pressure ac corona discharge (15 kHz, 2.6 kVptp ) was generated by using a stainless steel acupuncture needle. The generated ions were measured using an ion trap mass spectrometer. A comparative study on ac and direct current (dc) corona APCI ion sources was carried out using triacetone triperoxide and trinitrotoluene as test samples. The ac corona discharge gave ion signals as strong as dc corona discharge for both positive and negative ion modes. In addition, softer ionization was obtained with ac corona discharge than with dc corona discharge. The erosion of the needle tip induced by ac corona was less than that obtained with positive mode dc corona. A good 'yardstick' for assessing ac corona is that it can be used for both positive and negative ion modes without changing the polarity of the high-voltage power supply. Thus, ac corona can be an alternative to conventional dc corona for APCI ion sources. Copyright © 2013 John Wiley & Sons, Ltd.

Preliminary measurements of plasma fluctuations in an 8-cm mercury ion thruster

NASA Technical Reports Server (NTRS)

Serafini, J. S.; Nakanishi, S.

1975-01-01

The rms magnitude, spectra, and cross correlations for the fluctuations in the beam current, the neutralizer keeper current, and the discharge current and voltage were measured for an 8-cm diameter, dished grid ion thruster for a beam current of 72 milliamps. The ratio of the rms magnitude of the fluctuations to the time-mean neutralizer keeper current was found to depend significantly on the neutralizer time-mean keeper current, the flow rate, and keeper hold diameter. The maxima of the spectra of the beam current fluctuations did not depend on the discharge fluctuations. It was found that: (1) the discharge current fluctuations do not directly contribute to the beam current fluctuations; and (2) the neutralizer contributions to the beam fluctuations are small (for good neutralizer-to-beam coupling) but not negligible and appear mostly in the higher frequency range measured.

34 CFR 685.213 - Total and permanent disability discharge.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Loan based on a total and permanent disability, a borrower must submit a discharge application to the..., who is a doctor of medicine or osteopathy legally authorized to practice in a State, that the borrower... require the borrower to submit additional medical evidence if the Secretary determines that the borrower's...

34 CFR 685.213 - Total and permanent disability discharge.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Loan based on a total and permanent disability, a borrower must submit a discharge application to the..., who is a doctor of medicine or osteopathy legally authorized to practice in a State, that the borrower... require the borrower to submit additional medical evidence if the Secretary determines that the borrower's...

NEXIS Reservoir Cathode 2000 Hour Life Test

NASA Technical Reports Server (NTRS)

Vaughn, Jason; Schneider, Todd; Polk, Jay; Goebel, Dan; Ohlinger, Wayne; Hill, D. Norm

2004-01-01

The current design of the Nuclear Electric Xenon Ion System (NEXIS) employs a reservoir cathode as both the discharge and neutralizer cathode to meet the 10 yr thruster design life. The main difference between a reservoir cathode and a conventional discharge cathode is the source material (barium-containing compound) is contained within a reservoir instead of in an impregnated insert in the hollow tube. However, reservoir cathodes do not have much life test history associated with them. In order to demonstrate the feasibility of using a reservoir cathode as an integral part of the NEXIS ion thruster, a 2000 hr life test was performed. Several proof-of-concept (POC) reservoir cathodes were built early in the NEXIS program to conduct performance testing as well as life tests. One of the POC cathodes was sent to Marshall Space Flight Center (MSFC) where it was tested for 2000 hrs in a vacuum chamber. The cathode was operated at the NEXIS design point of 25 A discharge current and a xenon flow rate of 5.5 sccm during the 2000 hr test. The cathode performance parameters, including discharge current, discharge voltage, keeper current; keeper voltage, and flow rate were monitored throughout test. Also, the temperature upstream of cathode heater, the temperature downstream of the cathode heater, and the temperature of the orifice plate were monitored throughout the life of the test. The results of the 2000 hr test will be described in this paper. Included in the results will be time history of discharge current, discharge voltage, and flow rate. Also, a time history of the cathode temperature will be provided.

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.

High-current electron gun with a planar magnetron integrated with an explosive-emission cathode

NASA Astrophysics Data System (ADS)

Kiziridi, P. P.; Ozur, G. E.

2017-05-01

A new high-current electron gun with plasma anode and explosive-emission cathode integrated with planar pulsed powered magnetron is described. Five hundred twelve copper wires 1 mm in diameter and 15 mm in height serve as emitters. These emitters are installed on stainless steel disc (substrate) with 3-mm distance between them. Magnetron discharge plasma provides increased ion density on the periphery of plasma anode formed by high-current Penning discharge ignited within several milliseconds after starting of the magnetron discharge. The increased on the periphery ion density improves the uniformity of high-current electron beam produced in such an electron gun.

Evaluation of Acoustic Doppler Current Profiler to Measure Discharge at New York Power Authority's Niagara Power Project, Niagara Falls, New York

USGS Publications Warehouse

Zajd, Henry J.

2007-01-01

The need for accurate real-time discharge in the International Niagara River hydro power system requires reliable, accurate and reproducible data. The U.S. Geological Survey has been widely using Acoustic Doppler Current Profilers (ADCP) to accurately measure discharge in riverine channels since the mid-1990s. The use of the ADCP to measure discharge has remained largely untested at hydroelectric-generation facilities such as the New York Power Authority's (NYPA) Niagara Power Project in Niagara Falls, N.Y. This facility has a large, engineered diversion channel with the capacity of high volume discharges in excess of 100,000 cubic feet per second (ft3/s). Facilities such as this could benefit from the use of an ADCP, if the ADCP discharge measurements prove to be more time effective and accurate than those obtained from the flow-calculation techniques that are currently used. Measurements of diversion flow by an ADCP in the 'Pant Leg' diversion channel at the Niagara Power Project were made on November 6, 7, and 8, 2006, and compared favorably (within 1 percent) with those obtained concurrently by a conventional Price-AA current-meter measurement during one of the ADCP measurement sessions. The mean discharge recorded during each 2-hour individual ADCP measurement session compared favorably with (3.5 to 6.8 percent greater than) the discharge values computed by the flow-calculation method presently in use by NYPA. The use of ADCP technology to measure discharge could ultimately permit increased power-generation efficiency at the NYPA Niagara Falls Power Project by providing improved predictions of the amount of water (and thus the power output) available.

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.

Battery charging and discharging research based on the interactive technology of smart grid and electric vehicle

NASA Astrophysics Data System (ADS)

Zhang, Mingyang

2018-06-01

To further study the bidirectional flow problem of V2G (Vehicle to Grid) charge and discharge motor, the mathematical model of AC/DC converter and bi-directional DC/DC converter was established. Then, lithium battery was chosen as the battery of electric vehicle and its mathematical model was established. In order to improve the service life of lithium battery, bidirectional DC/DC converter adopted constant current and constant voltage control strategy. In the initial stage of charging, constant current charging was adopted with current single closed loop control. After reaching a certain value, voltage was switched to constant voltage charging controlled by voltage and current. Subsequently, the V2G system simulation model was built in MATLAB/Simulink. The simulation results verified the correctness of the control strategy and showed that when charging, constant current and constant voltage charging was achieved, the grid side voltage and current were in the same phase, and the power factor was about 1. When discharging, the constant current discharge was applied, and the grid voltage and current phase difference was r. To sum up, the simulation results are correct and helpful.

A Ti-V-based bcc phase alloy for use as metal hydride electrode with high discharge capacity

NASA Astrophysics Data System (ADS)

Yu, X. B.; Wu, Z.; Xia, B. J.; Xu, N. X.

2004-07-01

The electrochemical characteristics of single bcc phase Ti-30V-15Cr-15Mn alloy were investigated. It was demonstrated that the single bcc phase alloy has high electrochemical discharge performance at high temperature. Its discharge capacity is closely related with temperature and discharge current. The first discharge capacities of 580-814 mAh g-1 of the alloy powder were obtained at discharge current of 45-10 mA g-1 in 6 M KOH solution at 353 K. Although the electrochemical cycle life of the alloy is unsatisfactory at present, it opens up prospects for developing a new hydrogen storage alloy with high hydrogen capacity for use as high performance metal hydride electrodes in rechargeable Ni-MH battery.

A Ti-V-based bcc phase alloy for use as metal hydride electrode with high discharge capacity.

PubMed

Yu, X B; Wu, Z; Xia, B J; Xu, N X

2004-07-08

The electrochemical characteristics of single bcc phase Ti-30V-15Cr-15Mn alloy were investigated. It was demonstrated that the single bcc phase alloy has high electrochemical discharge performance at high temperature. Its discharge capacity is closely related with temperature and discharge current. The first discharge capacities of 580-814 mAh g(-1) of the alloy powder were obtained at discharge current of 45-10 mA g(-1) in 6 M KOH solution at 353 K. Although the electrochemical cycle life of the alloy is unsatisfactory at present, it opens up prospects for developing a new hydrogen storage alloy with high hydrogen capacity for use as high performance metal hydride electrodes in rechargeable Ni-MH battery.

Studies of Low-Current Back-Discharge in Point-Plane Geometry with Dielectric Layer

NASA Astrophysics Data System (ADS)

Jaworek, Anatol; Rajch, Eryk; Krupa, Andrzej; Czech, Tadeusz; Lackowski, Marcin

2006-01-01

The paper presents results of spectroscopic investigations of back-discharges generated in the point-plane electrode geometry in ambient air at atmospheric pressure, with the plane electrode covered with a dielectric layer. Fly ash from an electrostatic precipitator of a coal-fired power plant was used as the dielectric layer in these investigations. The discharges for positive and negative polarities of the needle electrode were studied by measuring optical emission spectra at two regions of the discharge: near the needle electrode and dielectric layer surface. The visual forms of the discharge were recorded and correlated with the current-voltage characteristics and optical emission spectra. The back-arc discharge was of particular interest in these studies due to its detrimental effects it causes in electrostatic precipitators.

All dressed up but nowhere to go? Delayed hospital discharges and older people.

PubMed

Glasby, Jon; Littlechild, Rosemary; Pryce, Kathryn

2006-01-01

Delayed hospital discharges are a key concern in a number of industrialized nations and are the subject of a range of government initiatives in the English National Health Service. The aim of this paper was to review the UK literature on delayed hospital discharges and older people in order to identify and explore the rate and causes of delayed hospital discharges, together with policies and practices that may reduce delayed discharges and improve the experiences of older people. Literature review based on searches of major health/social-care databases. Sources which explore the rate and cause of delayed discharges in the UK were included. Relevant documents were categorized using the research hierarchy set out in the National Service Framework for Older People and analysed according to criteria for appraising the quality of qualitative research proposed by Mays et al. The review identified 21 studies, which suggest very different rates and causes of delayed discharge in different settings. The studies reveal the importance of rehabilitation services to reduce the rate of delayed discharge, the prevalence of delayed discharges caused by internal hospital factors, and the complex and multi-faceted nature of the factors contributing to delayed discharge. Despite this, the studies have a number of methodological flaws and often fail to include a patient perspective or to consider detailed policies and approaches to reduce the number of delayed discharges. There is also a failure to consider the needs of older people with mental health problems or people from minority ethnic communities. The evidence, as it currently stands, raises a number of issues about current hospital discharge policy, supporting some aspects of the current government agenda in England, but questioning other aspects.

Field Assessment of Acoustic-Doppler Based Discharge Measurements

USGS Publications Warehouse

Mueller, D.S.; ,

2002-01-01

The use of equipment based on the Doppler principle for measuring water velocity and computing discharge is common within the U.S. Geological Survey (USGS). The instruments and software have changed appreciably during the last 5 years; therefore, the USGS has begun a field validation of the instruments currently (2002) available for making discharge measurements from a moving boat in streams of various sizes. Instruments manufactured by SonTek/YSI2 and RD Instruments, Inc. were used to collect discharge data at five different sites. One or more traditional discharge measurements were made by the use of a Price AA current meter and standard USGS procedures with the acoustic instruments at each site during data collection. The discharges measured with the acoustic instruments were compared with the discharges measured with Price AA meters and the current USGS stage-discharge rating for each site. The mean discharges measured by each acoustic instrument were within 5 percent of the Price AA-based measurement and (or) discharge from the stage-discharge rating. Additional analysis of the data collected indicates that the coefficient of variation of the discharge measurements consistently was less for the RD Instruments, Inc. Rio Grandes than it was for the SonTek/YSI RiverSurveyors. The bottom-tracking referenced measurement had a lower coefficient of variation than the differentially corrected global positioning system referenced measurements. It was observed that the higher frequency RiverSurveyors measured a moving bed more often than the lower frequency Rio Grandes. The detection of a moving bed caused RiverSurveyors to be consistently biased low when referenced to bottom tracking. Differentially corrected global positioning system data may be used to remove the bias observed in the bottom-tracking referenced measurements.

Investigation of atmospheric pressure glow microdischarge between flat cathode and needle anode in helium and argon

NASA Astrophysics Data System (ADS)

Astafiev, Alexander; Belyaev, Vladimir; Zamchii, Roman; Kudryavtsev, Anatoly; Stepanova, Olga; Chen, Zhaoquan

2016-09-01

DC atmospheric-pressure glow microdischarge was generated between a flat cathode and needle anode with a diameter of 100 μm in a special chamber with helium or argon. Dependences of discharge parameters on an interelectrode gap was investigated with an original experimental setup based on a movable arm on the hinge joint which allowed changing the gap with a step of 5 μm. The gap was varied from 5 to 700 μm. Discharge current was 1-21 mA. Such discharge cell has a very low interelectrode capacitance and provides increasing the stability of the discharge against arc formation (transition to RC oscillations mode) at low currents of 1 mA. A weak dependence of discharge voltage across the gap was revealed in helium at 100-250 μm between the electrodes (normal discharge). In contrast to this, glow microdischarge in argon has a descending current-voltage characteristic and unstable nature. The discharge voltage depending on the gap changes significantly slower than in helium. According to our estimations, the strength of electrical field of positive glow in argon is 5 times lower than in helium. Saint Petersburg State University (Grant No. 0.37.218.2016).

Behavior of Combined Dielectric-Metallic Systems in a Charged Particle Environment

NASA Technical Reports Server (NTRS)

Gordon, W. L.; Hoffman, R. W.

1984-01-01

The charging and discharging characteristics of an electrically isolated solar array segment were studied in order to simulate discharges seen during geomagnetic substorms. A solar array segment was floated while bombarded with monoenergetic electrons at various angles of incidence. The potentials of the array surface and of the interconnects were monitored using Trek voltage probes to maintain electrical isolation. A back plate was capacitively coupled to the array to provide information on the characteristics of the transients accompanying the discharges. Several modes of discharging of the array were observed at relatively low differential and absolute potentials (a few kilovolts). A relatively slow discharge response in the array was observed, discharging over one second with currents of nanoamps. Two types of faster discharges were also seen which lasted a few hundredths of a millisecond and with currents on the order of microamps. Some results indicate an electron emission process associated with the arcs.

General field and office procedures for indirect discharge measurements

USGS Publications Warehouse

Benson, M.A.; Dalrymple, Tate

2001-04-01

The discharge of streams is usually measured by the current-meter method. During flood periods, however, it is frequently impossible or impractical to measure the discharges by this method when they occur. Consequently, many peak discharges must be determined after the passage of the flood by indirect methods, such as slope-area, contracted-opening, flow-over-dam, and flow-through-culvert, rather than by direct current-meter measurement. Indirect methods of determining peak discharge are based on hydraulic equations which relate the discharge to the water-surface profile and the geometry of the channel. A field survey is made after the flood to determine the location and elevation of high-water marks and the characteristics of the channel. Detailed descriptions of the general procedures used in collecting the field data and in computing the discharge are given in this report. Each of the methods requires special procedures described in subsequent chapters.

Anomalous cross-B field transport and spokes in HiPIMS plasma

NASA Astrophysics Data System (ADS)

Hecimovic, Ante; Maszl, Christian; Schulz-von der Gathen, Volker; von Keudell, Achim

2016-09-01

The rotation of localised ionisation zones, i.e. spokes, in magnetron discharge is investigated as a function of discharge current, ranging from 10 mA (current density 0.5 mA cm-2) to 140 A (7 A cm-2) . The presence of spokes throughout the complete discharge current range indicates that the spokes are an intrinsic property of a magnetron sputtering plasma discharge. Up to discharge currents of several amperes, the spokes rotate in a retrograde ExB direction and beyond the spokes rotate in a ExB direction. In this contribution we present experimental evidence that anomalous diffusion is triggered by the appearance of spokes rotating in the ExB direction. The Hall parameter ωceτc , product of the electron cyclotron frequency and the classical collision time, reduces from Bohm diffusion values (16 and higher) down to the value of 3 as spokes appear, indicating anomalous cross-B field transport. The ion diffusion coefficients calculated from a sideways image of the spoke is six times higher than Bohm diffusion coefficients, which is consistent with the reduction of the Hall parameter.

Scale Factor Study for 1:30 Local Scour Model

DTIC Science & Technology

2016-08-01

railway crossing on the Santa Ana River near Corona , CA. Data from the scale factor study provide an adjustment for applying documented scour...upstream and downstream of the test section respectively. Discharge into the model came from three recirculation pumps with a total capacity of ERDC...upstream baffle blocks. The total discharge was measured by reading the differential from a manometer across a venturi meter and verified with a total

Performance of a vanadium redox flow battery with tubular cell design

NASA Astrophysics Data System (ADS)

Ressel, Simon; Laube, Armin; Fischer, Simon; Chica, Antonio; Flower, Thomas; Struckmann, Thorsten

2017-07-01

We present a vanadium redox flow battery with a tubular cell design which shall lead to a reduction of cell manufacturing costs and the realization of cell stacks with reduced shunt current losses. Charge/discharge cycling and polarization curve measurements are performed to characterize the single test cell performance. A maximum current density of 70 mAcm-2 and power density of 142 Wl-1 (per cell volume) is achieved and Ohmic overpotential is identified as the dominant portion of the total cell overpotential. Cycling displays Coulomb efficiencies of ≈95% and energy efficiencies of ≈55%. During 113 h of operation a stable Ohmic cell resistance is observed.

Variability in Antithrombotic Therapy Regimens Peri-TAVR: A Single Academic Center Experience.

PubMed

Rossi, Jeffrey E; Noll, Andrew; Bergmark, Brian; McCabe, James M; Nemer, David; Okada, David R; Vasudevan, Anant; Davidson, Michael; Welt, Frederick; Eisenhauer, Andrew; Shah, Pinak; Giugliano, Robert

2015-12-01

The aim of this study was to describe peri-procedural antithrombotic use in patients undergoing transcatheter aortic valve replacement (TAVR) at a single academic medical center. Retrospective collection of antiplatelet and anticoagulant use during the index hospitalization for all patients undergoing TAVR at our institution from April 2009 through March 2014. Of a total of 255 patients undergoing the procedure, 132 (51%) had an indication for anticoagulation pre-TAVR and 92 (70% of those with an indication) were on treatment. On discharge, 106 patients (44% of total surviving to discharge, 73% of those surviving with an indication for anticoagulation) were treated with oral anticoagulation. Of these patients, 89 (84%) were discharged on aspirin and an oral anticoagulant without clopidogrel. Only 122 (51% of total patients) were discharged on the regimen of aspirin and clopidogrel alone. Peri-procedural antithrombotic regimens vary greatly following TAVR. More than half of patients have an indication for anticoagulation following the procedure. Most patients at our institution who require anticoagulation are discharged on aspirin and an oral anticoagulant, though the optimal regimen requires further investigation.

Expression of the P/Q (Cav2.1) calcium channel in nodose sensory neurons and arterial baroreceptors.

PubMed

Tatalovic, Milos; Glazebrook, Patricia A; Kunze, Diana L

2012-06-27

The predominant calcium current in nodose sensory neurons, including the subpopulation of baroreceptor neurons, is the N-type channel, Cav2.2. It is also the primary calcium channel responsible for transmitter release at their presynaptic terminals in the nucleus of the solitary tract in the brainstem. The P/Q channel, Cav2.1, the other major calcium channel responsible for transmitter release at mammalian synapses, represents only 15-20% of total calcium current in the general population of sensory neurons and makes a minor contribution to transmitter release at the presynaptic terminal. In the present study we identified a subpopulation of the largest nodose neurons (capacitance>50pF) in which, surprisingly, Cav2.1 represents over 50% of the total calcium current, differing from the remainder of the population. Consistent with these electrophysiological data, anti-Cav2.1 antibody labeling was more membrane delimited in a subgroup of the large neurons in slices of nodose ganglia. Data reported in other synapses in the central nervous system assign different roles in synaptic information transfer to the P/Q-type versus N-type calcium channels. The study raises the possibility that the P/Q channel which has been associated with high fidelity transmission at other central synapses serves a similar function in this group of large myelinated sensory afferents, including arterial baroreceptors where a high frequency regular discharge pattern signals the pressure pulse. This contrasts to the irregular lower frequency discharge of the unmyelinated fibers that make up the majority of the sensory population and that utilize the N-type channel in synaptic transmission. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

[Impact of a software application to improve medication reconciliation at hospital discharge].

PubMed

Corral Baena, S; Garabito Sánchez, M J; Ruíz Rómero, M V; Vergara Díaz, M A; Martín Chacón, E R; Fernández Moyano, A

2014-01-01

To assess the impact of a software application to improve the quality of information concerning current patient medications and changes on the discharge report after hospitalization. To analyze the incidence of errors and to classify them. Quasi-experimental pre / post study with non-equivalent control group study. Medical patients at hospital discharge. implementation of a software application. Percentage of reconciled patient medication on discharge, and percentage of patients with more than one unjustified discrepancy. A total of 349 patients were assessed; 199 (pre-intervention phase) and 150 (post-intervention phase). Before the implementation of the application in 157 patients (78.8%) medication reconciliation had been completed; finding reconciliation errors in 99 (63.0%). The most frequent type of error, 339 (78.5%), was a missing dose or administration frequency information. After implementation, all the patient prescriptions were reconciled when the software was used. The percentage of patients with unjustified discrepancies decreased from 63.0% to 11.8% with the use of the application (p<.001). The main type of discrepancy found on using the application was confusing prescription, due to the fact that the professionals were not used to using the new tool. The use of a software application has been shown to improve the quality of the information on patient treatment on the hospital discharge report, but it is still necessary to continue development as a strategy for improving medication reconciliation. Copyright © 2014 SECA. Published by Elsevier Espana. All rights reserved.

Incidence of symptomatic venous thromboembolism in 2372 knee and hip replacement patients after discharge: data from a thromboprophylaxis registry in Montreal, Canada.

PubMed

Senay, Andréa; Trottier, Milanne; Delisle, Josée; Banica, Andreea; Benoit, Benoit; Laflamme, G Yves; Malo, Michel; Nguyen, Hai; Ranger, Pierre; Fernandes, Julio C

2018-01-01

Low-molecular-weight heparin (LMWH) is a recommended anticoagulant for thromboprophylaxis after major orthopedic surgery. Dabigatran etexilate is an oral anticoagulant recognized as noninferior to LMWH. We aimed to assess the incidence of symptomatic venous thromboembolic events (VTEs) after discharge in patients who underwent joint replacement, using a hospital registry. Patients who underwent total knee and hip arthroplasty between September 2011 and March 2015 were selected. Subcutaneous enoxaparin (30 mg twice daily) was given during hospitalization. At discharge, patients received either enoxaparin 30 mg twice daily/40 mg once daily or dabigatran 220 mg/150 mg once daily. Patients were seen or called at 2, 6, and 12 weeks after surgery. Outcomes were the number of VTEs, including deep venous thrombosis, pulmonary embolism, and the number of major/minor bleeding events after discharge. After discharge, 1468 patients were prescribed enoxaparin and 904 dabigatran (1396 total knee arthroplasty and 976 total hip arthroplasty patients). Mean age was 66±10 years, and 60% were female. The cumulative incidence of VTEs during the 12-week follow-up was 0.7%. One patient sustained a VTE during the switch window. Seven patients sustained a pulmonary embolism (0.3%). There was no statistical difference between the total knee arthroplasty and total hip arthroplasty groups. The incidence of major and minor bleeding events during follow-up was 0.3% and 30.3%, respectively. These events had a higher incidence in the dabigatran group compared to the enoxaparin group after discharge ( p <0.05), but not between knee and hip replacement groups for major bleeding events. A pharmaceutical prophylaxis protocol using LMWH and dabigatran during the post-discharge period resulted in low incidences of VTE and equivalence between treatments. However, the increased number of major and minor bleeding events in patients taking dabigatran is of concern regarding the safety and needs to be evaluated using analyses adjusted for risk factors.

Enhanced reproducibility of L-mode plasma discharges via physics-model-based q-profile feedback control in DIII-D

NASA Astrophysics Data System (ADS)

Schuster, E.; Wehner, W. P.; Barton, J. E.; Boyer, M. D.; Luce, T. C.; Ferron, J. R.; Holcomb, C. T.; Walker, M. L.; Humphreys, D. A.; Solomon, W. M.; Penaflor, B. G.; Johnson, R. D.

2017-11-01

Recent experiments on DIII-D demonstrate the potential of physics-model-based q-profile control to improve reproducibility of plasma discharges. A combined feedforward  +  feedback control scheme is employed to optimize the current ramp-up phase by consistently achieving target q profiles (Target 1: q_min=1.3, q95=4.4 ; Target 2: q_min=1.65, q95=5.0 ; Target 3: q_min=2.1, q95=6.2 ) at prescribed times during the plasma formation phase (Target 1: t=1.5 s; Target 2: t=1.3 s; Target 3: t=1.0 s). At the core of the control scheme is a nonlinear, first-principles-driven, physics-based, control-oriented model of the plasma dynamics valid for low confinement (L-mode) scenarios. To prevent undesired L-H transitions, a constraint on the maximum allowable total auxiliary power is imposed in addition to the maximum powers for the individual heating and current-drive sources. Experimental results are presented to demonstrate the effectiveness of the combined feedforward  +  feedback control scheme to consistently achieve the desired target profiles at the predefined times. These results also show how the addition of feedback control significantly improves upon the feedforward-only control solution by reducing the matching error and also how the feedback controller is able to reduce the matching error as the constraint on the maximum allowable total auxiliary power is relaxed while keeping the plasma in L-mode.

Theoretical Study of Methods for Improving the Energy Efficiency of NOx Removal from Diesel Exhaust Gases by Silent Discharge

NASA Astrophysics Data System (ADS)

Shoyama, Taiji; Yoshioka, Yoshio

To improve the NO removal performance in silent discharge process, we investigated the influence of the physical parameters such as current density, channel radius and pulse duration of the one micro discharge under the constant reduced electric field strength. And influence of the micro discharges occurrence locations were also discussed. In order to analyze the NO removal process, we assumed that the pulse micro discharges occur repeatedly at the same location in static gas and that the chemical reactions induced by micro discharge forms many radicals, which react with pollutants and by-products. The conclusions we obtained are that lower current density, smaller discharge radius and shorter discharge duration improve NO removal efficiency. These results also mean that the lower discharge energy of the one micro discharge and the larger number of parallel micro discharges increase the NO removal performance. Therefore, to make the area of one micro discharge small is a desirable way to improve the NO removal performance. So we think that the glow like discharge might be more effective than the streamer like discharge mode. Next, using the two-dimensional model, which considered the influence of gas flow, we obtained a conclusion that the repeated micro discharges at different positions are very effective to increase the De-NOx performance. The reason is that the reaction of NO2+O→NO+O2 and ozone dissociation reactions are suppressed by the movement of the location of micro discharges.

Liposomal Bupivacaine Suspension, Can Reduce Length of Stay and Improve Discharge Status of Patients Undergoing Total Hip Arthroplasty.

PubMed

Cherian, Jeffrey J; Barrington, John; Elmallah, Randa K; Chughtai, Morad; Mistry, Jaydev B; Mont, Michael A

2015-11-01

To ensure good rehabilitation and improved outcomes following total hip arthroplasty (THA), optimal pain control is necessary. Newer methods of pain control have been advocated, as current modalities have been associated with undesirable side effects and serious complications. One such modality is liposomal bupivacaine, which provides long-acting, slow-release analgesia. The purpose of this study was to evaluate: (1) lengths of hospital stay and (2) the discharge status of patients who underwent THA with liposomal bupivacaine compared to a cohort who received standard analgesic regimens. We utilized a hospital discharge database from July 1, 2013 to June 30, 2014, which included 7,704,919 patients for our analysis. We selected patients aged 18 years or older who had an inpatient stay for THA using ICD-9 procedure code (ICD-9-CM = 81.51), which resulted in 55,129 THA patients. Patients who had a nerve block in the time period from the surgery date to the discharge date were then excluded, which resulted in 54,604 THA patients. The THA cohort who received liposomal bupivacaine suspension consisted of 5,267 patients (2,907 women; 2,360 men) who had a mean age of 64 years, while the THA without injections or nerve block consisted of 49,337 patients who had a mean age of 65 years that consisted of 27,530 women and 21,807 men. We analyzed length-of-stay by controlling for race, region, age, sex, Charlson Index, and operating time using a log link linear model with a negative binomial distribution. The discharge status to home compared to short-term nursing facility or rehabilitation was analyzed using logistic regression while controlling for the aforementioned covariates. The mean lengths of stay, after adjusting for covariates, for the liposomal bupivacaine cohort was significantly shorter than the no injection cohort. The distribution of patients being discharged to home compared to a short-term nursing facility or a rehabilitation facility was higher in the liposomal bupivacaine cohort compared to the cohort who did not receive liposomal bupivacaine. Multivariate logistic regression analyses demonstrated a higher likelihood of being discharged to home in liposomal bupivacaine cohort when compared to no injection. Liposomal bupivacaine appears to be an effective pain relief modality that leads to reduced lengths of hospital stay and increased rates of discharge to home. This may be an appropriate addition for the analgesic armamentarium in patients who undergo THA.

One-dimensional Numerical Model of Transient Discharges in Air of a Spatial Plasma Ignition Device

NASA Astrophysics Data System (ADS)

Saceleanu, Florin N.

This thesis examines the modes of discharge of a plasma ignition device. Oscilloscope data of the discharge voltage and current are analyzed for various pressures in air at ambient temperature. It is determined that the discharge operates in 2 modes: a glow discharge and a postulated streamer discharge. Subsequently, a 1-dimensional fluid simulation of plasma using the finite volume method (FVM) is developed to gain insight into the particle kinetics. Transient results of the simulation agree with theories of electric discharges; however, quasi-steady state results were not reached due to high diffusion time of ions in air. Next, an ordinary differential equation (ODE) is derived to understand the discharge transition. Simulated results were used to estimate the voltage waveform, which describes the ODE's forcing function; additional simulated results were used to estimate the discharge current and the ODE's non-linearity. It is found that the ODE's non-linearity increases exponentially for capacitive discharges. It is postulated that the non-linearity defines the mode transition observed experimentally. The research is motivated by Spatial Plasma Discharge Ignition (SPDI), an innovative ignition system postulated to increase combustion efficiency in automobile engines for up to 9%. The research thus far can only hypothesize SPDI's benefits on combustion, based on the literature review and the modes of discharge.

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.

[Current situation and impact factors of acid deposition in main cites of Shandong Province].

PubMed

Jia, Hong-yu; Zhang, Qiao-xian; Deng, Hong-bing; Zhao, Jing-zhu; Mu, Jin-bo; Zhang, De-zhi

2006-12-01

Based on the monitoring data for years in Shandong Province, current situation of acid rain in every city was assessed, and the temporal distribution of the dry, wet and total sulfur deposition in Jinan and Qingdao were studied. The results showed that Qingdao which had the largest precipitation acidity was the single city whose annul average precipitation pH was below 5. 60. The precipitation acidities in the main cities of Shandong Province were in a descent tendency. The total sulfur desposition in Jinan and Qingdao was basically stable or in a descent tendency, but also reached 10 t/(km(2)x a) or so. Among the total sulfur deposition flux, the dry deposition of sulfur had the greater contribution, and the contribution of SO2 dry deposition was higher than that of SO42- dry deposition. By analyzing the relation between the precipitation acidity and the SO2 discharge intensity, soil acidity and meteorological condition, the impact factors of acid precipitation in the cities of Shandong Province were revealed.

Ion extraction capabilities of two-grid accelerator systems. M.S. Thesis

NASA Technical Reports Server (NTRS)

Rovang, D. C.; Wilbur, P. J.

1984-01-01

An experimental investigation into the ion extraction capabilities of two-grid accelerator systems common to electrostatic ion thrusters is described. This work resulted in a large body of experimental data which facilitates the selection of the accelerator system geometries and operating parameters necessary to maximize the extracted ion current. Results suggest that the impingement-limited perveance is not dramatically affected by reductions in screen hole diameter to 0.5 mm. Impingement-limited performance is shown to depend most strongly on grid separation distance, accelerator hole diameter ratio, the discharge-to-total accelerating voltage ratio, and the net-to-total accelerating voltage ratio. Results obtained at small grid separation ratios suggest a new grid operating condition where high beam current per hole levels are achieved at a specified net accelerating voltage. It is shown that this operating condition is realized at an optimum ratio of net-to-total accelerating voltage ratio which is typically quite high. The apparatus developed for this study is also shown to be well suited measuring the electron backstreaming and electrical breakdown characteristics of two-grid accelerator systems.

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.

Design and development of a low cost, high current density power supply for streamer free atmospheric pressure DBD plasma generation in air.

PubMed

Jain, Vishal; Visani, Anand; Srinivasan, R; Agarwal, Vivek

2018-03-01

This paper presents a new power supply architecture for generating a uniform dielectric barrier discharge (DBD) plasma in air medium at atmospheric pressure. It is quite a challenge to generate atmospheric pressure uniform glow discharge plasma, especially in air. This is because air plasma needs very high voltage for initiation of discharge. If the high voltage is used along with high current density, it leads to the formation of streamers, which is undesirable for most applications like textile treatment, etc. Researchers have tried to generate high-density plasma using a RF source, nanosecond pulsed DC source, and medium frequency AC source. However, these solutions suffer from low current discharge and low efficiency due to the addition of an external resistor to control the discharge current. Moreover, they are relatively costly and bulky. This paper presents a new power supply configuration which is very compact and generates high average density (∼0.28 W/cm 2 ) uniform glow DBD plasma in air at atmospheric pressure. The efficiency is also higher as no external resistor is required to control the discharge current. An inherent feature of this topology is that it can drive higher current oscillations (∼50 A peak and 2-3 MHz frequency) into the plasma that damp out due to the plasma dissipation only. A newly proposed model has been used with experimental validation in this paper. Simulations and experimental validation of the proposed topology are included. Also, the application of the generated plasma for polymer film treatment is demonstrated.

Design and development of a low cost, high current density power supply for streamer free atmospheric pressure DBD plasma generation in air

NASA Astrophysics Data System (ADS)

Jain, Vishal; Visani, Anand; Srinivasan, R.; Agarwal, Vivek

2018-03-01

This paper presents a new power supply architecture for generating a uniform dielectric barrier discharge (DBD) plasma in air medium at atmospheric pressure. It is quite a challenge to generate atmospheric pressure uniform glow discharge plasma, especially in air. This is because air plasma needs very high voltage for initiation of discharge. If the high voltage is used along with high current density, it leads to the formation of streamers, which is undesirable for most applications like textile treatment, etc. Researchers have tried to generate high-density plasma using a RF source, nanosecond pulsed DC source, and medium frequency AC source. However, these solutions suffer from low current discharge and low efficiency due to the addition of an external resistor to control the discharge current. Moreover, they are relatively costly and bulky. This paper presents a new power supply configuration which is very compact and generates high average density (˜0.28 W/cm2) uniform glow DBD plasma in air at atmospheric pressure. The efficiency is also higher as no external resistor is required to control the discharge current. An inherent feature of this topology is that it can drive higher current oscillations (˜50 A peak and 2-3 MHz frequency) into the plasma that damp out due to the plasma dissipation only. A newly proposed model has been used with experimental validation in this paper. Simulations and experimental validation of the proposed topology are included. Also, the application of the generated plasma for polymer film treatment is demonstrated.

Hydrographic surveys at seven chutes and three backwaters on the Missouri River in Nebraska, Iowa, and Missouri, 2011-13

USGS Publications Warehouse

Krahulik, Justin R.; Densmore, Brenda K.; Anderson, Kayla J.; Kavan, Cory L.

2015-01-01

Discharge was measured at chute survey sites, in both the main channel of the Missouri River upstream from the chute and the chute. Many chute entrances and control structures were damaged by floodwater during the 2011 Missouri River flood, allowing a larger percentage of the total Missouri River discharge to flow through the chute than originally intended in the chute design. Measured discharge split between the main channel and the chute at most chutes was consistent with effects of the 2011 Missouri River flood damages and a larger percent of the total Missouri River discharge was flowing through the chute than originally intended. The U.S. Army Corps of Engineers repaired many of these chutes in 2012 and 2013, and the resulting hydraulic changes are reflected in the discharge splits.

Suspended sediment transport in the freshwater reach of the Hudson river estuary in eastern New York

USGS Publications Warehouse

Wall, G.R.; Nystrom, E.A.; Litten, S.

2008-01-01

Deposition of Hudson River sediment into New York Harbor interferes with navigation lanes and requires continuous dredging. Sediment dynamics at the Hudson estuary turbidity maximum (ETM) have received considerable study, but delivery of sediment to the ETM through the freshwater reach of the estuary has received relatively little attention and few direct measurements. An acoustic Doppler current profiler was positioned at the approximate limit of continuous freshwater to develop a 4-year time series of water velocity, discharge, suspended sediment concentration, and suspended sediment discharge. This data set was compared with suspended sediment discharge data collected during the same period at two sites just above the Hudson head-of-tide (the Federal Dam at Troy) that together represent the single largest source of sediment entering the estuary. The mean annual suspended sediment-discharge from the freshwater reach of the estuary was 737,000 metric tons. Unexpectedly, the total suspended sediment discharge at the study site in November and December slightly exceeded that observed during March and April, the months during which rain and snowmelt typically result in the largest sediment discharge to the estuary. Suspended sediment discharge at the study site exceeded that from the Federal Dam, even though the intervening reach appears to store significant amounts of sediment, suggesting that 30-40% of sediment discharge observed at the study site is derived from tributaries to the estuary between the Federal Dam and study site. A simple model of sediment entering and passing through the freshwater reach on a timescale of weeks appears reasonable during normal hydrologic conditions in adjoining watersheds; however, this simple model may dramatically overestimate sediment delivery during extreme tributary high flows, especially those at the end of, or after, the "flushing season" (October through April). Previous estimates of annual or seasonal sediment delivery from tributaries and the Federal Dam to the ETM and harbor may be high for those years with extreme tributary high-flow events. ?? 2008 Coastal and Estuarine Research Federation.

Trends in nitrogen concentration and nitrogen loads entering the South Shore Estuary Reserve from streams and ground-water discharge in Nassau and Suffolk counties, Long Island, New York, 1952–97

USGS Publications Warehouse

Monti, Jack; Scorca, Michael P.

2003-01-01

The 13 major south-shore streams in Nassau and Suffolk Counties, Long Island, New York with adequate long-term (1971-97) water-quality records, and 192 south-shore wells with sufficient water-quality data, were selected for analysis of geographic, seasonal, and long-term trends in nitrogen concentration. Annual total nitrogen loads transported to the South Shore Estuary Reserve (SSER) from 11 of these streams were calculated using long-term discharge records. Nitrogen loads from shallow and deep ground water also were calculated using simulated ground-water discharge of 1968-83 hydrologic conditions.Long-term declines in stream discharge occurred in East Meadow Brook, Bellmore Creek and Massapequa Creek in response to extensive sewering in Nassau County. The smallest longterm annual discharge to the SSER was from the westernmost stream, Pines Brook, which is in an area in which the water table has been lowered by sewers since 1952. The three largest average annual discharges to the SSER were from the Connetquot River, Carlls River, and Carmans River in Suffolk County; the discharges from each of these streams were at least twice those of the other streams considered in this study.Total nitrogen concentrations in streams show a geographic trend with a general eastward increase in median total nitrogen concentration in Nassau County and a decreasing trend from Massapequa Creek eastward into Suffolk County. Total nitrogen concentrations in streams generally are lowest during summer and highest in winter as a result of seasonal fluctuations in chemical reactions and biological activity. The greatest seasonal difference in median total nitrogen concentration was at Carlls River with values of 3.4 and 4.2 mg/L (milligrams per liter) as N during summer (April through September) and winter (October through March), respectively. Streams affected by the completion of sewer districts show long-term (1971-97) trends of decreasing total nitrogen concentration and streams showing an increase in total nitrogen concentration are in unsewered areas with increased urbanization.Discharges from shallow ground water (upper glacial aquifer) and deep ground water (upper part of Magothy aquifer) were simulated from a ground-water-flow model calibrated to steadystate (1968-83) conditions. Simulated discharges from shallow-ground-water system in Nassau County were 10,700 Mgal/yr (million gallons per year) or 40,500,000 m3/yr (cubic meters per year), and those from Suffolk County were 52,300 Mgal/yr or 198,000,000 m3/yr. Discharges from deep-ground-water system in Nassau County were 4,900 Mgal/yr or 18,500,000 m3/yr, and those in Suffolk County were 12,700 Mgal/yr or 48,200,000 m3/yr.Ground-water concentrations of nitrogen decrease with depth and from west to east. The shallow ground water median nitrogen concentration for each county was determined using 1,155 samples collected at 167 shallow wells (125 feet deep or less) within 1 mile of the shore. The deep ground water median nitrate concentration (nitrate represented almost all of the total nitrogen) for each county was determined using 112 samples collected at 25 deep wells (greater than 125 feet deep) within 1 mile of the shore. The median nitrogen concentration for the shallow and median nitrate concentration for the deep ground water in Nassau County were 3.85 and 0.15 mg/L as N, during 1952–97; the corresponding concentrations for Suffolk County were 1.74 and <0.10 (less than 0.10) mg/L as N, during 1952–97.Nitrogen loads discharged from streams to the SSER for each year during 1972–97 were calculated as the annual total nitrogen concentration multiplied by the annual discharge. These values were calculated only for the seven streams for which sufficient data were available. The largest long-term (1972–97) average annual nitrogen load from Carlls River was 104 ton/yr or 94,300 kg/yr—about twice that of Connetquot River (54 ton/yr or 48,900 kg/yr) and over three times that of Carmans River (33 ton/yr or 29,900 kg/yr). The smallest annual mean nitrogen load was from Pines Brook, which has the lowest annual mean discharge of all streams analyzed.The nitrogen load carried to the SSER by ground-water discharge in shallow-ground-water system in Nassau and Suffolk Counties was calculated as the simulated discharge for each county multiplied by the respective median nitrogen concentration, and loads from deep-ground-water system were calculated as the simulated discharge for each county multiplied by the respective median nitrate concentration. All discharges were obtained from the U.S. Geological Survey's Long Island ground-water-flow model. The resultant nitrogen loads discharged to the SSER from shallow ground water were 172 ton/yr (156,000 kg/yr) from Nassau County and 380 ton/yr (345,000 kg/yr) from Suffolk County; equaling 552 ton/yr entering the SSER. Those from deep ground water were 3 ton/yr (2,700 kg/yr) from Nassau County and <0.5 ton/yr (480 kg/yr) from Suffolk County; equaling about 3.5 ton/yr entering the SSER.The sum of both stream loads and groundwater loads results in the total load to the SSER. The largest calculated total nitrogen load entering the SSER from both streams and ground water occurred in 1979 with a total load of 1,260 ton/yr (1,140,000 kg/yr). The smallest calculated nitrogen load entering the SSER occurred in 1995 with a total load of 725 ton/yr (658,000 kg/yr).

Reduced sediment transport in the Chinese Loess Plateau due to climate change and human activities.

PubMed

Yang, Xiaonan; Sun, Wenyi; Li, Pengfei; Mu, Xingmin; Gao, Peng; Zhao, Guangju

2018-06-14

The sediment load on the Chinese Loess Plateau has sharply decreased in recent years. However, the contribution of terrace construction and vegetation restoration projects to sediment discharge reduction remains uncertain. In this paper, eight catchments located in the Loess Plateau were chosen to explore the effects of different driving factors on sediment discharge changes during the period from the 1960s to 2012. Attribution approaches were applied to evaluate the effects of climate, terrace, and vegetation coverage changes on sediment discharge. The results showed that the annual sediment discharge decreased significantly in all catchments ranging from -0.007 to -0.039 Gt·yr -1 . Sediment discharge in most tributaries has shown abrupt changes since 1996, and the total sediment discharge was reduced by 60.1% during 1997-2012. We determined that increasing vegetation coverage was the primary factor driving the reductions in sediment loads since 1996 and accounted for 47.7% of the total reduction. Climate variability and terrace construction accounted for 9.1% and 18.6% of sediment discharge reductions, respectively. Copyright © 2018. Published by Elsevier B.V.

Consistent and efficient processing of ADCP streamflow measurements

USGS Publications Warehouse

Mueller, David S.; Constantinescu, George; Garcia, Marcelo H.; Hanes, Dan

2016-01-01

The use of Acoustic Doppler Current Profilers (ADCPs) from a moving boat is a commonly used method for measuring streamflow. Currently, the algorithms used to compute the average depth, compute edge discharge, identify invalid data, and estimate velocity and discharge for invalid data vary among manufacturers. These differences could result in different discharges being computed from identical data. Consistent computational algorithm, automated filtering, and quality assessment of ADCP streamflow measurements that are independent of the ADCP manufacturer are being developed in a software program that can process ADCP moving-boat discharge measurements independent of the ADCP used to collect the data.

Dynamics of the plasma current sheath in plasma focus discharges in different gases

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

Vinogradov, V. P.; Krauz, V. I., E-mail: krauz-vi@nrcki.ru; Mokeev, A. N.

2016-12-15

The shape of the plasma current sheath (PCS) in the final stage of its radial compression, the dynamics of pinching, and the subsequent pinch decay in plasma focus (PF) discharges in different gases are studied using an improved multichannel system of electron-optical plasma photography and a newly elaborated synchronization system. The PCS structure in discharges in heavy gases (Ne, Ar) is found to differ significantly from that in discharges in hydrogen and deuterium. The influence of a heavy gas (Xe) additive to hydrogen and deuterium on the structure and compression dynamics of the PCS is investigated.

Heavy component of spent nuclear fuel: Efficiency of model-substance ionization by electron-induced discharge

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

Antonov, N. N., E-mail: antonovnickola@gmail.com; Gavrikov, A. V.; Samokhin, A. A.

The method of plasma separation of spent nuclear fuel can be tested with a model substance which has to be transformed from the condensed to plasma state. For this purpose, electron-induced discharge in lead vapor injected into the interelectrode gap is simulated using the kinetic approach. The ionization efficiency, the electrostatic-potential distribution, and those of the ion and electron densities in the discharge gap are derived as functions of the discharge-current density and concentration of the vapor of the model substance. Given a discharge-current density of 3.5 A/cm{sup 2} and a lead-vapor concentration of 2 × 10{sup 12} cm{sup –3},more » the simulated ionization efficiency proves to be nearly 60%. The discharge in lead vapor is also investigated experimentally.« less

The effect of real-time teleconsultations between hospital-based nurses and patients with severe COPD discharged after an exacerbation.

PubMed

Sorknaes, Anne Dichmann; Bech, Mickael; Madsen, Hanne; Titlestad, Ingrid L; Hounsgaard, Lise; Hansen-Nord, Michael; Jest, Peder; Olesen, Finn; Lauridsen, Joergen; Østergaard, Birte

2013-12-01

We investigated the effect of daily real-time teleconsultations for one week between hospital-based nurses specialised in respiratory diseases and patients with severe COPD discharged after acute exacerbation. Patients admitted with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) at two hospitals were recruited at hospital discharge. They were randomly assigned to intervention or control. The telemedicine equipment consisted of a briefcase with built-in computer including a web camera, microphone and measurement equipment. The primary outcome was the mean number of total hospital readmissions within 26 weeks of discharge. A total of 266 patients (mean age 72 years) were allocated to either intervention (n = 132) or control (n = 134). There was no significant difference in the unconditional total mean number of hospital readmissions after 26 weeks: mean 1.4 (SD 2.1) in the intervention group and 1.6 (SD 2.4) in the control group. In a secondary analysis, there was no significant difference between the two groups in mortality, time to readmission, mean number of total hospital readmissions, mean number of readmissions with AECOPD, mean number of total hospital readmission days or mean number of readmission days with AECOPD calculated at 4, 8, 12 and 26 weeks. Thus the addition of one week of teleconsultations between hospital-based nurses and patients with severe COPD discharged after hospitalisation did not significantly reduce readmissions or affect mortality.

Pulse charging of lead-acid traction cells

NASA Technical Reports Server (NTRS)

Smithrick, J. J.

1980-01-01

Pulse charging, as a method of rapidly and efficiently charging 300 amp-hour lead-acid traction cells for an electric vehicle application was investigated. A wide range of charge pulse current square waveforms were investigated and the results were compared to constant current charging at the time averaged pulse current values. Representative pulse current waveforms were: (1) positive waveform-peak charge pulse current of 300 amperes (amps), discharge pulse-current of zero amps, and a duty cycle of about 50%; (2) Romanov waveform-peak charge pulse current of 300 amps, peak discharge pulse current of 15 amps, and a duty of 50%; and (3) McCulloch waveform peak charge pulse current of 193 amps, peak discharge pulse current of about 575 amps, and a duty cycle of 94%. Experimental results indicate that on the basis of amp-hour efficiency, pulse charging offered no significant advantage as a method of rapidly charging 300 amp-hour lead-acid traction cells when compared to constant current charging at the time average pulse current value. There were, however, some disadvantages of pulse charging in particular a decrease in charge amp-hour and energy efficiencies and an increase in cell electrolyte temperature. The constant current charge method resulted in the best energy efficiency with no significant sacrifice of charge time or amp-hour output. Whether or not pulse charging offers an advantage over constant current charging with regard to the cell charge/discharge cycle life is unknown at this time.

Characterization of polycrystalline nickel cobaltite nanostructures prepared by DC plasma magnetron co-sputtering for gas sensing applications

NASA Astrophysics Data System (ADS)

Hammadi, Oday A.; Naji, Noor E.

2018-03-01

In this work, a gas sensor is fabricated from polycrystalline nickel cobaltite nano films deposited on transparent substrates by closed-field unbalanced dual-magnetrons (CFUBDM) co-sputtering technique. Two targets of nickel and cobalt are mounted on the cathode of discharge system and co-sputtered by direct current (DC) argon discharge plasma in presence of oxygen as a reactive gas. The total gas pressure is 0.5 mbar and the mixing ratio of Ar:O2 gases is 5:1. The characterization measurements performed on the prepared films show that their transmittance increases with the incident wavelength, the polycrystalline structure includes 5 crystallographic planes, the average particle size is about 35 nm, the electrical conductivity is linearly increasing with increasing temperature, and the activation energy is about 0.41 eV. These films show high sensitivity to ethanol vapor.

extrap: Software to assist the selection of extrapolation methods for moving-boat ADCP streamflow measurements

USGS Publications Warehouse

Mueller, David S.

2013-01-01

profiles from the entire cross section and multiple transects to determine a mean profile for the measurement. The use of an exponent derived from normalized data from the entire cross section is shown to be valid for application of the power velocity distribution law in the computation of the unmeasured discharge in a cross section. Selected statistics are combined with empirically derived criteria to automatically select the appropriate extrapolation methods. A graphical user interface (GUI) provides the user tools to visually evaluate the automatically selected extrapolation methods and manually change them, as necessary. The sensitivity of the total discharge to available extrapolation methods is presented in the GUI. Use of extrap by field hydrographers has demonstrated that extrap is a more accurate and efficient method of determining the appropriate extrapolation methods compared with tools currently (2012) provided in the ADCP manufacturers’ software.

Modification of polycarbonate surface in oxidizing plasma

NASA Astrophysics Data System (ADS)

Ovtsyn, A. A.; Smirnov, S. A.; Shikova, T. G.; Kholodkov, I. V.

2017-11-01

The properties of the surface of the film polycarbonate Lexan 8010 were experimentally studied after treatment in a DC discharge plasma in oxygen and air at pressures of 50-300 Pa and a discharge current of 80 mA. The contact angles of wetting and surface energies are measured. The topography of the surface was investigated by atomic force microscopy. The chemical composition of the surface was determined from the FT-IR spectroscopy data in the variant of total internal reflection, as well as X-ray photoelectron spectroscopy. Treatment in the oxidizing plasma leads to a change in morphology (average roughness increases), an increase in the surface energy, and the concentration of oxygen-containing groups (hydroxyl groups, carbonyl groups in ketones or aldehydes and in oxyketones) on the surface of the polymer. Possible reasons for the difference in surface properties of polymer under the action of oxygen and air plasma on it are discussed.

Discharge properties of Mg-Al-Mn-Ca and Mg-Al-Mn alloys as anode materials for primary magnesium-air batteries

NASA Astrophysics Data System (ADS)

Yuasa, Motohiro; Huang, Xinsheng; Suzuki, Kazutaka; Mabuchi, Mamoru; Chino, Yasumasa

2015-11-01

The discharge behaviors of rolled Mg-6 mass%Al-0.3 mass%Mn-2 mass%Ca (AMX602) and Mg-6 mass%Al-0.3 mass%Mn (AM60) alloys used as anodes for Magnesium-air batteries were investigated. The AMX602 alloy exhibited superior discharge properties compared to the AM60 alloy, especially at low current density. The discharge products of the AMX602 alloy were dense and thin, and many cracks were observed at all current densities. In addition, the discharge products were detached at some sites. These sites often corresponded to the positions of Al2Ca particles. The comparison of the discharge and corrosion tests indicated that the dense and thin discharge products of AMX602 were easily cracked by dissolution of the Mg matrix around Al2Ca particles, and the cracks promoted the penetration of the electrolyte into the discharge products, retaining the discharge activity. In contrast, concerning the AM60 alloy, thick discharge products were formed on the surface during discharge, and cracking of the discharge products hardly occurred, degrading the discharge properties. Localized and deeply corroded pits that could result from the detachment of metal pieces from the anode during discharge were partly observed in the AM60 alloy. It is suggested that these detached metal pieces are another reason for the low discharge properties of the AM60 alloy.

Electrophysiology of neurones of the inferior mesenteric ganglion of the cat.

PubMed Central

Julé, Y; Szurszewski, J H

1983-01-01

Intracellular recordings were obtained from cells in vitro in the inferior mesenteric ganglia of the cat. Neurones could be classified into three types: non-spontaneous, irregular discharging and regular discharging neurones. Non-spontaneous neurones had a stable resting membrane potential and responded with action potentials to indirect preganglionic nerve stimulation and to intracellular injection of depolarizing current. Irregular discharging neurones were characterized by a discharge of excitatory post-synaptic potentials (e.p.s.p.s.) which sometimes gave rise to action potentials. This activity was abolished by hexamethonium bromide, chlorisondamine and d-tubocurarine chloride. Tetrodotoxin and a low Ca2+ -high Mg2+ solution also blocked on-going activity in irregular discharging neurones. Regular discharging neurones were characterized by a rhythmic discharge of action potentials. Each action potential was preceded by a gradual depolarization of the intracellularly recorded membrane potential. Intracellular injection of hyperpolarizing current abolished the regular discharge of action potential. No synaptic potentials were observed during hyperpolarization of the membrane potential. Nicotinic, muscarinic and adrenergic receptor blocking drugs did not modify the discharge of action potentials in regular discharging neurones. A low Ca2+ -high Mg2+ solution also had no effect on the regular discharge of action potentials. Interpolation of an action potential between spontaneous action potentials in regular discharging neurones reset the rhythm of discharge. It is suggested that regular discharging neurones were endogenously active and that these neurones provided synaptic input to irregular discharging neurones. PMID:6140310

Electrophysiology of neurones of the inferior mesenteric ganglion of the cat.

PubMed

Julé, Y; Szurszewski, J H

1983-11-01

Intracellular recordings were obtained from cells in vitro in the inferior mesenteric ganglia of the cat. Neurones could be classified into three types: non-spontaneous, irregular discharging and regular discharging neurones. Non-spontaneous neurones had a stable resting membrane potential and responded with action potentials to indirect preganglionic nerve stimulation and to intracellular injection of depolarizing current. Irregular discharging neurones were characterized by a discharge of excitatory post-synaptic potentials (e.p.s.p.s.) which sometimes gave rise to action potentials. This activity was abolished by hexamethonium bromide, chlorisondamine and d-tubocurarine chloride. Tetrodotoxin and a low Ca2+ -high Mg2+ solution also blocked on-going activity in irregular discharging neurones. Regular discharging neurones were characterized by a rhythmic discharge of action potentials. Each action potential was preceded by a gradual depolarization of the intracellularly recorded membrane potential. Intracellular injection of hyperpolarizing current abolished the regular discharge of action potential. No synaptic potentials were observed during hyperpolarization of the membrane potential. Nicotinic, muscarinic and adrenergic receptor blocking drugs did not modify the discharge of action potentials in regular discharging neurones. A low Ca2+ -high Mg2+ solution also had no effect on the regular discharge of action potentials. Interpolation of an action potential between spontaneous action potentials in regular discharging neurones reset the rhythm of discharge. It is suggested that regular discharging neurones were endogenously active and that these neurones provided synaptic input to irregular discharging neurones.

Discharge-measurement system using an acoustic Doppler current profiler with applications to large rivers and estuaries

USGS Publications Warehouse

Simpson, Michael R.; Oltmann, Richard N.

1993-01-01

Discharge measurement of large rivers and estuaries is difficult, time consuming, and sometimes dangerous. Frequently, discharge measurements cannot be made in tide-affected rivers and estuaries using conventional discharge-measurement techniques because of dynamic discharge conditions. The acoustic Doppler discharge-measurement system (ADDMS) was developed by the U.S. Geological Survey using a vessel-mounted acoustic Doppler current profiler coupled with specialized computer software to measure horizontal water velocity at 1-meter vertical intervals in the water column. The system computes discharge from water-and vessel-velocity data supplied by the ADDMS using vector-algebra algorithms included in the discharge-measurement software. With this system, a discharge measurement can be obtained by engaging the computer software and traversing a river or estuary from bank to bank; discharge in parts of the river or estuarine cross sections that cannot be measured because of ADDMS depth limitations are estimated by the system. Comparisons of ADDMS-measured discharges with ultrasonic-velocity-meter-measured discharges, along with error-analysis data, have confirmed that discharges provided by the ADDMS are at least as accurate as those produced using conventional methods. In addition, the advantage of a much shorter measurement time (2 minutes using the ADDMS compared with 1 hour or longer using conventional methods) has enabled use of the ADDMS for several applications where conventional discharge methods could not have been used with the required accuracy because of dynamic discharge conditions.

Ion energy spread and current measurements of the rf-driven multicusp ion source

NASA Astrophysics Data System (ADS)

Lee, Y.; Gough, R. A.; Kunkel, W. B.; Leung, K. N.; Perkins, L. T.; Pickard, D. S.; Sun, L.; Vujic, J.; Williams, M. D.; Wutte, D.

1997-03-01

Axial energy spread and useful beam current of positive ion beams have been carried out using a radio frequency (rf)-driven multicusp ion source. Operating the source with a 13.56 MHz induction discharge, the axial energy spread is found to be approximately 3.2 eV. The extractable beam current of the rf-driven source is found to be comparable to that of filament-discharge sources. With a 0.6 mm diameter extraction aperture, a positive hydrogen ion beam current density of 80 mA/cm2 can be obtained at a rf input power of 2.5 kW. The expected source lifetime is much longer than that of filament discharges.

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

Validity of the stroke rehabilitation assessment of movement scale in acute rehabilitation: a comparison with the functional independence measure and stroke impact scale-16.

PubMed

Ward, Irene; Pivko, Susan; Brooks, Gary; Parkin, Kate

2011-11-01

To demonstrate sensitivity to change of the Stroke Rehabilitation Assessment of Movement (STREAM) as well as the concurrent and predictive validity of the STREAM in an acute rehabilitation setting. Prospective cohort study. Acute, in-patient rehabilitation department within a tertiary-care teaching hospital in the United States. Thirty adults with a newly diagnosed, first ischemic stroke. Clinical assessments were conducted on admission and then again on discharge from the rehabilitation hospital with the STREAM (total STREAM and upper extremity, lower extremity, and mobility subscales), Functional Independence Measure (FIM), and Stroke Impact Scale-16 (SIS-16). Sensitivity to change was determined with the Wilcoxon signed rank test and by the calculation of standardized response means. Spearman correlations were used to assess concurrent validity of the total STREAM and STREAM subscales with the FIM and SIS-16 on admission and discharge. We determined predictive validity for all instruments by correlating admission scores with actual and predicted length of stay and by testing associations between admission scores and discharge destination (home vs subacute facility). Not applicable. For all instruments, there was statistically significant improvement from admission to discharge. The standardized response means for the total STREAM and STREAM subscales were large. Spearman correlations between the total STREAM and STREAM subscales and the FIM and SIS-16 were moderate to excellent, both on admission and discharge. Among change scores, only the SIS-16 correlated with the total STREAM. All 3 instruments were significantly associated with discharge destination; however, the associations were strongest for the total STREAM and STREAM subscales. All instruments showed moderate-to-excellent correlations with predicted and actual length of stay. The STREAM is sensitive to change and demonstrates good concurrent and predictive validity as compared with the FIM and SIS-16 in the acute inpatient rehabilitation population. Copyright © 2011 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Validation of exposure time for discharge measurements made with two bottom-tracking acoustic doppler current profilers

USGS Publications Warehouse

Czuba, J.A.; Oberg, K.

2008-01-01

Previous work by Oberg and Mueller of the U.S. Geological Survey in 2007 concluded that exposure time (total time spent sampling the flow) is a critical factor in reducing measurement uncertainty. In a subsequent paper, Oberg and Mueller validated these conclusions using one set of data to show that the effect of exposure time on the uncertainty of the measured discharge is independent of stream width, depth, and range of boat speeds. Analysis of eight StreamPro acoustic Doppler current profiler (ADCP) measurements indicate that they fall within and show a similar trend to the Rio Grande ADCP data previously reported. Four special validation measurements were made for the purpose of verifying the conclusions of Oberg and Mueller regarding exposure time for Rio Grande and StreamPro ADCPs. Analysis of these measurements confirms that exposure time is a critical factor in reducing measurement uncertainty and is independent of stream width, depth, and range of boat speeds. Furthermore, it appears that the relation between measured discharge uncertainty and exposure time is similar for both Rio Grande and StreamPro ADCPs. These results are applicable to ADCPs that make use of broadband technology using bottom-tracking to obtain the boat velocity. Based on this work, a minimum of two transects should be collected with an exposure time for all transects greater than or equal to 720 seconds in order to achieve an uncertainty of ??5 percent when using bottom-tracking ADCPs. ?? 2008 IEEE.

Sensitivity Testing of the NSTAR Ion Thruster

NASA Technical Reports Server (NTRS)

Sengupta, Anita; Anderson, John; Brophy, John

2007-01-01

During the Extended Life Test of the DS1 flight spare ion thruster, the engine was subjected to sensitvity testing in order to characterize the macroscopic dependence of discharge chamber sensitivity to a +\\-3% vatiation in main flow, cathode flow and beam current, and to +\\5% variation in beam and accelerator voltage, was determined for the minimum- (THO), half- (TH8) and full power (TH15) throttle levels. For each power level investigared, 16 high/low operating conditions were chosen to vary the flows, beam current, and grid voltages in in a matrix that mapped out the entire parameter space. The matrix of data generated was used to determine the partial derivative or senitivity of the dependent parameters--discharge voltage, discharge current, discharge loss, double-to-single-ion current ratio, and neutralizer-keeper voltage--to the variation in the independent parameters--main flow, cathode flow, beam current, and beam voltage. The sensititivities of each dependent parameter with respect to each independent parameter were determined using a least-square fit routine. Variation in these sensitivities with thruster runtime was recorded over the duration of the ELT, to detemine if discharge performance changed with thruster wear. Several key findings have been ascertained from the sensitivity testing. Discharge operation is most sensitve to changes in cathode flow and to a lesser degree main flow. The data also confirms that for the NSTAR configuration plasma production is limited by primary electron input due to the fixed neutral population. Key sensitivities along with their change with thruster wear (operating time) will be presented. In addition double ion content measurements with an ExB probe will also be presented to illustrate beam ion production and content sensitivity to the discharge chamber operating parameteres.

Current-voltage characteristics of dc corona discharges in air between coaxial cylinders

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

Zheng, Yuesheng, E-mail: yueshengzheng@fzu.edu.cn; Zhang, Bo, E-mail: shizbcn@tsinghua.edu.cn; He, Jinliang, E-mail: hejl@tsinghua.edu.cn

This paper presents the experimental measurement and numerical analysis of the current-voltage characteristics of dc corona discharges in air between coaxial cylinders. The current-voltage characteristics for both positive and negative corona discharges were measured within a specially designed corona cage. Then the measured results were fitted by different empirical formulae and analyzed by the fluid model. The current-voltage characteristics between coaxial cylinders can be expressed as I = C(U − U{sub 0}){sup m}, where m is within the range 1.5–2.0, which is similar to the point-plane electrode system. The ionization region has no significant effect on the current-voltage characteristic under a low corona current,more » while it will affect the distribution for the negative corona under a high corona current. The surface onset fields and ion mobilities were emphatically discussed.« less

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

Comparison of fusion alpha performance in JET advanced scenario and H-mode plasmas

NASA Astrophysics Data System (ADS)

Asunta, O.; Kurki-Suonio, T.; Tala, T.; Sipilä, S.; Salomaa, R.; contributors, JET-EFDA

2008-12-01

Currently, plasmas with internal transport barriers (ITBs) appear the most likely candidates for steady-state scenarios for future fusion reactors. In such plasmas, the broad hot and dense region in the plasma core leads to high fusion gain, while the cool edge protects the integrity of the first wall. Economically desirable large bootstrap current fraction and low inductive current drive may, however, lead to degraded fast ion confinement. In this work the confinement and heating profile of fusion alphas were compared between H-mode and ITB plasmas in realistic JET geometry. The work was carried out using the Monte Carlo-based guiding-center-following code ASCOT. For the same plasma current, the ITB discharges were found to produce four to eight times more fusion power than a comparable ELMy H-mode discharge. Unfortunately, also the alpha particle losses were larger (~16%) compared with the H-mode discharge (7%). In the H-mode discharges, alpha power was deposited to the plasma symmetrically around the magnetic axis, whereas in the current-hole discharge, the power was spread out to a larger volume in the plasma center. This was due to wider particle orbits, and the magnetic structure allowing for a broader hot region in the centre.

Quantifying the impacts of vegetation changes on catchment storage-discharge dynamics using paired-catchment data

NASA Astrophysics Data System (ADS)

Cheng, Lei; Zhang, Lu; Chiew, Francis H. S.; Canadell, Josep G.; Zhao, Fangfang; Wang, Ying-Ping; Hu, Xianqun; Lin, Kairong

2017-07-01

It is widely recognized that vegetation changes can significantly affect the local water availability. Methods have been developed to predict the effects of vegetation change on water yield or total streamflow. However, it is still a challenge to predict changes in base flow following vegetation change due to limited understanding of catchment storage-discharge dynamics. In this study, the power law relationship for describing catchment storage-discharge dynamics is reformulated to quantify the changes in storage-discharge relationship resulting from vegetation changes using streamflow data from six paired-catchment experiments, of which two are deforestation catchments and four are afforestation catchments. Streamflow observations from the paired-catchment experiments clearly demonstrate that vegetation changes have led to significant changes in catchment storage-discharge relationships, accounting for about 83-128% of the changes in groundwater discharge in the treated catchments. Deforestation has led to increases in groundwater discharge (or base flow) but afforestation has resulted in decreases in groundwater discharge. Further analysis shows that the contribution of changes in groundwater discharge to the total changes in streamflow varies greatly among experimental catchments ranging from 12% to 80% with a mean of 38 ± 22% (μ ± σ). This study proposed a new method to quantify the effects of vegetation changes on groundwater discharge from catchment storage and will improve our predictability about the impacts of vegetation changes on catchment water yields.

The Effects of Self-Discharge on the Performance of Symmetric Electric Double-Layer Capacitors and Active Electrolyte-Enhanced Supercapacitors: Insights from Modeling and Simulation

NASA Astrophysics Data System (ADS)

Ike, Innocent S.; Sigalas, Iakovos; Iyuke, Sunny E.

2017-02-01

The effects of self-discharge on the performance of symmetric electric double-layer capacitors (EDLCs) and active electrolyte-enhanced supercapacitors were examined by incorporating self-discharge into electrochemical capacitor models during charging and discharging. The sources of self-discharge in capacitors were side reactions or redox reactions and several impurities and electric double-layer (EDL) instability. The effects of self-discharge during capacitor storage was negligible since it took a fully charged capacitor a minimum of 14.0 days to be entirely discharged by self-discharge in all conditions studied, hence self-discharge in storage condition can be ignored. The first and second charge-discharge cycle energy efficiencies η_{{{{E}}1}} and η_{{{{E}}2}} of a capacitor of electrode effective conductivity α1 = 0.05 S/cm with only EDL instability self-discharge with current density J_{{VR}} = 1.25 × 10-3 A/cm2 were 72.33% and 72.34%, respectively. Also, energy efficiencies η_{{{{E}}1}} and η_{{{{E}}2}} of a similar capacitor with both side reactions and redox reactions and EDL instability self-discharges with current densities J_{{VR}} = 0.00125 A/cm2 and J_{{{{VR}}1}} = 0.0032 A/cm2 were 38.13% and 38.14% respectively, compared with 84.24% and 84.25% in a similar capacitor without self-discharge. A capacitor with only EDL instability self-discharge and that with both side reactions and redox reactions and EDL instability self-discharge lost 9.73 Wh and 28.38 Wh of energy, respectively, through self-discharge during charging and discharging. Hence, EDLCs charging and discharging time is significantly dependent on the self-discharge rate which are too large to be ignored.

Conversion of nitrogen oxides in N2:O2:CO2 and N2:O2:CO2:NO2 mixtures subjected to a dc corona discharge

NASA Astrophysics Data System (ADS)

Dors, Mirosław; Mizeraczyk, Jerzy

1996-10-01

This paper concerns the influence of a direct current (dc) corona discharge on production and reduction of NO, NO2 and N2O in N2:O2:CO2 and N2:O2:CO2:NO2 mixtures. The corona discharge was generated in a needle-to-plate reactor. The positively polarized electrode consisted of 7 needles. The grounded electrode was a stainless steel plate. The gas flow rate through the reactor was varied from 28 to 110 cm3/s. The time-averaged discharge current ranged from 0 to 6 mA. It was found that in the N2:O2:CO2 mixture the corona discharge produced NO, NO2 and N2O. In the N2:O2:CO2:NO2 mixture the reduction of NO2 was between 6-56%, depending on the concentration of O2, gas flow rate and corona discharge current. The NO2 reduction was accompanied by production of NO and N2O. The results show that efficient reduction of nitrogen oxides by a corona discharge cannot be expected in the mixtures containing N2 and O2 if reducing additives are not employed.

Estimating suspended sediment and trace element fluxes in large river basins: Methodological considerations as applied to the NASQAN programme

USGS Publications Warehouse

Horowitz, A.J.; Elrick, K.A.; Smith, J.J.

2001-01-01

In 1994, the NASQAN (National Stream Quality Accounting Network) programme was redesigned as a flux-based water-quality monitoring network for the Mississippi, Columbia, Colorado, and Rio Grande Basins. As the new programme represented a departure from the original, new sampling, processing, analytical, and data handling procedures had to be selected/developed to provide data on discharge, suspended sediment concentration, and the concentrations of suspended sediment and dissolved trace elements. Annual suspended sediment fluxes were estimated by summing daily instantaneous fluxes based on predicted suspended sediment concentrations derived from discharge-based log-log regression (rating-curve) models. The models were developed using both historical and current site-specific discharge and suspended sediment concentrations. Errors using this approach typically are less than ?? 10% for the 3-year reporting period; however, the magnitude of the errors increases substantially for temporal spans shorter than 1 year. Total, rather than total-recoverable, suspended sediment-associated trace element concentrations were determined by direct analysis of material dewatered from large-volume whole-water samples. Site-specific intra- and inter-annual suspended sediment-associated chemical variations were less (typically by no more than a factor of two) than those for either discharge or suspended sediment concentrations (usually more than 10-fold). The concentrations, hence the annual fluxes, for suspended sediment-associated phosphorus and organic carbon, determined by direct analyses, were higher than those determined using a more traditional paired, whole-water/filtered-water approach (by factors ranging from 1.5- to 10-fold). This may be important for such issues as eutrophication and coastal productivity. Filtered water-associated (dissolved) trace element concentrations were markedly lower than those determined during the historical NASQAN programme; many were below their respective detection limits. This resulted from the use of clean sampling, processing, and analytical protocols. Hence, the fluxes for filtered water-associated (dissolved) Ag, Pb, Co, V, Be, Sb, and Se, as well as the total (filtered water plus suspended sediment-associated) fluxes for these constituents, could not be estimated.

Census of mental hospital patients and life expectancy of those unlikely to be discharged.

PubMed Central

Bewley, T; Bland, J M; Ilo, M; Walch, E; Willington, G

1975-01-01

A census in a London mental hospital was performed so that the numbers of patients requiring permanent care for the next 20 to 40 years could be estimated. Of 1467 resident patients 20% had been admitted in the preceding five months and 15% in the year before that. Of the 65% who had been in hospital for over 17 months 1% (16 patients) had been in hospital for over 5o years. Altogether 257 (18%) patients would probably be discharged, 339 (23%) might possibly be discharged if there were adequate community facilities, but 871 (59%) were not likely to be discharged; 239 patients under the age of 65 who had been admitted between 1950 and 1973 were unlikely to be discharged. There were about 10 new younger long-stay patients from each year's admissions. Three conditions--schizophrenia, organic brain syndrome, and affective illness--affected 79% of the population. Fourteen per cent had been employed on admission and 28% were considered employable or possibly employable. Half of those who might be considered for discharge (296) would need a hostel. No rehabilitation was needed or possible for 40% of the patients; 299 (20%) patients were chairbound or bedridden and 400 (27%) were totally dependent on nursing and 587 (40%) partly dependent. Twenty months after the census 361 (25%) patients had left (59 had been readmitted), 284 (19%) had died, and 822 (56%) had remained as inpatients. The most realistic future prediction was that 210 (14%) of these patients would still be in the hospital in 20 years and 43 (3%) in 40 years. In the light of these findings and the scarceness of resources current Department of Health and Social Security plans for phasing out mental hospitals must be challenged. PMID:812584

Spoke rotation reversal in magnetron discharges of aluminium, chromium and titanium

NASA Astrophysics Data System (ADS)

Hecimovic, A.; Maszl, C.; Schulz-von der Gathen, V.; Böke, M.; von Keudell, A.

2016-06-01

The rotation of localised ionisation zones, i.e. spokes, in magnetron discharge are frequently observed. The spokes are investigated by measuring floating potential oscillations with 12 flat probes placed azimuthally around a planar circular magnetron. The 12-probe setup provides sufficient temporal and spatial resolution to observe the properties of various spokes, such as rotation direction, mode number and angular velocity. The spokes are investigated as a function of discharge current, ranging from 10 mA (current density 0.5 mA cm-2) to 140 A (7 A cm-2). In the range from 10 mA to 600 mA the plasma was sustained in DC mode, and in the range from 1 A to 140 A the plasma was pulsed in high-power impulse magnetron sputtering mode. The presence of spokes throughout the complete discharge current range indicates that the spokes are an intrinsic property of a magnetron sputtering plasma discharge. The spokes may disappear at discharge currents above 80 A for Cr, as the plasma becomes homogeneously distributed over the racetrack. Up to discharge currents of several amperes (the exact value depends on the target material), the spokes rotate in a retrograde \\mathbf{E}× \\mathbf{B} direction with angular velocity in the range of 0.2-4 km s-1. Beyond a discharge current of several amperes, the spokes rotate in a \\mathbf{E}× \\mathbf{B} direction with angular velocity in the range of 5-15 km s-1. The spoke rotation reversal is explained by a transition from Ar-dominated to metal-dominated sputtering that shifts the plasma emission zone closer to the target. The spoke itself corresponds to a region of high electron density and therefore to a hump in the electrical potential. The electric field around the spoke dominates the spoke rotation direction. At low power, the plasma is further away from the target and it is dominated by the electric field to the anode, thus retrograde \\mathbf{E}× \\mathbf{B} rotation. At high power, the plasma is closer to the target and it is dominated by the electric field pointing to the target, thus \\mathbf{E}× \\mathbf{B} rotation.

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.

Effects of Weather Variables on Ascospore Discharge from Fusarium graminearum Perithecia

PubMed Central

Manstretta, Valentina; Rossi, Vittorio

2015-01-01

Fusarium graminearum is a predominant component of the Fusarium head blight (FHB) complex of small grain cereals. Ascosporic infection plays a relevant role in the spread of the disease. A 3-year study was conducted on ascospore discharge. To separate the effect of weather on discharge from the effect of weather on the production and maturation of ascospores in perithecia, discharge was quantified with a volumetric spore sampler placed near maize stalk residues bearing perithecia with mature ascospores; the residues therefore served as a continuous source of ascospores. Ascospores were discharged from perithecia on 70% of 154 days. Rain (R) and vapor pressure deficit (VPD) were the variables that most affected ascospore discharge, with 84% of total discharges occurring on days with R≥0.2 mm or VPD≤11 hPa, and with 70% of total ascospore discharge peaks (≥ 30 ascospores/m3 air per day) occurring on days with R≥0.2 mm and VPD≤6.35 hPa. An ROC analysis using these criteria for R and VPD provided True Positive Proportion (TPP) = 0.84 and True Negative Proportion (TNP) = 0.63 for occurrence of ascospore discharge, and TPP = 0.70 and TNP = 0.89 for occurrence of peaks. Globally, 68 ascospores (2.5% of the total ascospores sampled) were trapped on the 17 days when no ascospores were erroneously predicted. When a discharge occurred, the numbers of F. graminearum ascospores sampled were predicted by a multiple regression model with R2 = 0.68. This model, which includes average and maximum temperature and VPD as predicting variables, slightly underestimated the real data and especially ascospore peaks. Numbers of ascospores in peaks were best predicted by wetness duration of the previous day, minimum temperature, and VPD, with R2 = 0.71. These results will help refine the epidemiological models used as decision aids in FHB management programs. PMID:26402063

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).

Consolidation of materials by pulse-discharge processes

NASA Astrophysics Data System (ADS)

Strizhakov, E. L.; Nescoromniy, S. V.

2017-07-01

The article presents the research and the analysis of the pulse-discharge processes of capacitor discharge sintering: CD Stud Welding, capacitor discharge percussion welding (CDPW), high-voltage capacitor welding with an inductive-dynamic drive (HVCW with IDD), pulse electric current sintering (PECS) of powders. The comparative analysis of the impact parameter is presented.

Large discharge capacity from carbon electrodes in sulfuric acid with oxidant

NASA Astrophysics Data System (ADS)

Inagaki, M.; Iwashita, N.

The discharge performance of the graphite intercalation compounds in sulfuric acid containing nitric acid (H 2SO 4-GICs) was studied by focusing on the effects of oxidant and carbon nanotexture. A large discharge capacity from H 2SO 4-GICs synthesized by using an excess amount of HNO 3, more than 150 times of the theoretical value (93 mAh/g carbon), was obtained depending on the amount of oxidant added, the discharge current, and the nanotexture of carbon electrode. The experimental results are explained in terms of competition between the de-intercalation of sulfuric acid due to galvanostatic reduction and the re-intercalation due to chemical oxidation by HN03 during discharging. However, a subsidiary reaction decreases the effective amount of HNO 3 on the discharge by a small current and also on the cycle of chemical charging and electrochemical discharging. The oxidant KMnO 4 gave only a little larger capacity for discharge than the theoretical one, because it was reduced to the manganese oxide precipitates during the oxidation of the carbon electrode.

Investigation of heavy current discharges with high initial gas density

NASA Astrophysics Data System (ADS)

Budin, A.; Bogomaz, A.; Kolikov, V.; Kuprin, A.; Leontiev, V.; Rutberg, Ph.; Shirokov, N.

1996-05-01

Piezoelectric pressure transducers, with noise immunity and time resolution of 0,5 μs were used to measure pulse pressures of 430 MPa along the axis of an electrical discharge channel. Initial concentration of He was 2,7ṡ1021cm-3, dI/dt=6ṡ1011 A/s, and Imax=560 kA. Shock waves with amplitudes exceeding the pressure along the axis, were detected by a pressure transducer on the wall of the discharge chamber. Typical shock velocities were 2ṡ4 km/s. Average pressure measurements along the discharge axis at different radii were used to estimate the current density distribution along the canal radius. The presence of the shock waves, promoting the additional hydrogen heating in the discharge chamber, has been registered during the discharge in hydrogen for Imax˜1 MA and an initial concentration of 1021cm-3.

Na-Zn liquid metal battery

NASA Astrophysics Data System (ADS)

Xu, Junli; Kjos, Ole Sigmund; Osen, Karen Sende; Martinez, Ana Maria; Kongstein, Ole Edvard; Haarberg, Geir Martin

2016-11-01

A new kind of membrane free liquid metal battery was developed. The battery employs liquid sodium and zinc as electrodes both in liquid state, and NaCl-CaCl2 molten salts as electrolyte. The discharge flat voltage is in the range of about 1.4 V-1.8 V, and the cycle efficiency achieved is about 90% at low discharge current densities (below 40 mA cm-2). Moreover, this battery can also be charged and discharged at high current density with good performance. The discharge flat voltage is above 1.1 V when it is discharged at 100 mA cm-2, while it is about 0.8 V with 100% cycle efficiency when it is discharged at 200 mA cm-2. Compared to other reported liquid metal battery, this battery has lower cost, which suggests broad application prospect in energy storage systems for power grid.

Effect of electronegative additives on physical properties and chemical activity of gas discharge plasma

NASA Astrophysics Data System (ADS)

Kuznetsov, D. L.; Filatov, I. E.; Uvarin, V. V.

2018-01-01

Effect of electronegative additives (oxygen O2, sulfur dioxide SO2, carbon disulfide CS2, and carbon tetrachloride CCl4) on physical properties and chemical activity of plasma formed by pulsed corona discharge and by non-self-sustained discharge supported by pulsed electron beam in atmospheric pressure gas mixtures was investigated. It is shown that a decrease in discharge current depends on a sort of the additive and on its concentration. The reason is the difference in rate constants of electron attachment processes for the above molecules. In experiments on volatile organic compounds (VOCs) conversion in air by streamer corona it is obtained that an addition of CCl4 both decreases the discharge current amplitude and increases the VOCs conversion degree. An installation for investigation of electron attachment processes and for study of toxic impurities conversion in plasma formed by non-self-sustained discharge initiated by pulsed nanosecond electron beam is created.

Influence of the Yukon River on the Bering Sea

NASA Technical Reports Server (NTRS)

Dean, K.; Mcroy, C. P.

1986-01-01

The relationships between the discharge of the Yukon River to the currents and biological productivity in the northern Bering Sea were studied. Specific objectives were: to develop thermal, sediment, and chlorophyll surface maps using Thematic Mapper (TM) data of the discharge of the Yukon River and the Alaskan Coastal Current during the ice free season; to develop a historical model of the distribution of the Yukon River discharge and the Alaskan Coastal Current using LANDSAT Multispectral band scanner (MSS) and NOAA satellite imagery; and to use high resolution TM data to define the surface dynamics of the front between the Alaskan Coastal Current and the Bering Shelf/Anadyr Current. LANDSAT MSS, TM, and Advanced Very High Resolution Radiometer (AVHRR) data were recorded during the 1985 ice free period. The data coincided with shipboard measurements acquired by Inner Shelf Transfer and Recycling (ISTAR) project scientists. An integrated model of the distribution of turbid water discharged from the Yukon River was compiled. A similar model is also being compiled for the Alaskan Coastal and Bering Shelf/Anadyr water masses based on their thermal expressions seen on AVHRR imagery.

Magnetic tearing of plasma discharges due to nonuniform resistivity

NASA Technical Reports Server (NTRS)

Hassam, A. B.

1988-01-01

The rearrangement of current in a plasma discharge in response to resistivity nonuniformities within a magnetic surface is studied. It is shown that macroscopic magnetic islands develop about those surfaces where the nonuniformity is aligned with the magnetic field. If the nonuniformity and the field are not aligned anywhere, there is no current rearrangement; instead, relatively large plasma flows are set up. Such resistivity inhomogeneities can obtain in solar coronal loops and, in some circumstances, in tokamak discharges.

Performance of an anaerobic, static bed, fixed film bioreactor for chlorinated solvent treatment

USGS Publications Warehouse

Lorah, Michelle M.; Walker, Charles; Graves, Duane

2015-01-01

Anaerobic, fixed film, bioreactors bioaugmented with a dechlorinating microbial consortium were evaluated as a potential technology for cost effective, sustainable, and reliable treatment of mixed chlorinated ethanes and ethenes in groundwater from a large groundwater recovery system. Bench- and pilot-scale testing at about 3 and 13,500 L, respectively, demonstrated that total chlorinated solvent removal to less than the permitted discharge limit of 100 μg/L. Various planned and unexpected upsets, interruptions, and changes demonstrated the robustness and reliability of the bioreactor system, which handled the operational variations with no observable change in performance. Key operating parameters included an adequately long hydraulic retention time for the surface area, a constant supply of electron donor, pH control with a buffer to minimize pH variance, an oxidation reduction potential of approximately −200 millivolts or lower, and a well-adapted biomass capable of degrading the full suite of chlorinated solvents in the groundwater. Results indicated that the current discharge criteria can be met using a bioreactor technology that is less complex and has less downtime than the sorption based technology currently being used to treat the groundwater.

Factors affecting return to oral intake in inpatient rehabilitation after acquired brain injury.

PubMed

Kjaersgaard, Annette; Nielsen, Lars Hedemann; Sjölund, Bengt H

2015-01-01

To extend previous observations by investigating if differences exist in time to initiation or to recovery of total oral intake in patients with acquired brain injury assessed by either Facial-Oral Tract Therapy (F.O.T.T.) or Fibreoptic Endoscopic Evaluation of Swallowing (FEES) and to investigate whether other factors influence these outcomes. Randomized controlled trial. One hundred and nineteen patients with dysphagia in inpatient neurorehabilitation were randomized. The main outcome was time to maximum on the Functional Oral Intake Scale. There was no difference in time to initiation or recovery of total oral intake using F.O.T.T. or FEES. Oral intake was initiated for 42% on admission and 92% at discharge; 2.5% of the patients were on total oral intake within 24 hours of admission and 37% at discharge. The likelihood of recovery to total oral intake before discharge was found to depend on age, Functional Independence Measure score, length of stay and number of dysphagia interventions. There was no significant difference in time to initiation and recovery of total oral intake before discharge, whether assessed by F.O.T.T. or FEES, indicating that an instrumental assessment is unnecessary for standard evaluation. Age, functional independence and length of stay had a significant influence.

Health-related quality of life anticipated with different management strategies for paediatric febrile neutropaenia

PubMed Central

Cheng, S; Teuffel, O; Ethier, M C; Diorio, C; Martino, J; Mayo, C; Regier, D; Wing, R; Alibhai, S M H; Sung, L

2011-01-01

Background: To describe (1) anticipated health-related quality of life during different strategies for febrile neutropaenia (FN) management and (2) attributes of those preferring inpatient management. Methods: Respondents were parents of children 0–18 years and children 12–18 years receiving cancer treatment. Anticipated health-related quality of life was elicited for four different FN management strategies: entire inpatient, early discharge, outpatient oral and outpatient intravenous (i.v.) therapy. Tools used to measure health-related quality of life were visual analogue scale (VAS), willingness to pay and time trade off. Results: A total of 155 parents and 43 children participated. For parents, median VAS scores were highest for early discharge (5.9, interquartile range 4.4–7.2) and outpatient i.v. (5.9, interquartile range 4.4–7.3). For children, median scores were highest for early discharge (6.1, interquartile range 4.6–7.2). In contrast, the most commonly preferred strategy for parents and children was inpatient in 55.0% and 37.2%, respectively. Higher current child health-related quality of life was associated with a stronger preference for outpatient management. Conclusion: Early discharge and outpatient i.v. management are associated with higher anticipated health-related quality of life, although the most commonly preferred strategy was inpatient care. This data may help with determining more cost-effective strategies for paediatric FN. PMID:21694729

Health-related quality of life anticipated with different management strategies for paediatric febrile neutropaenia.

PubMed

Cheng, S; Teuffel, O; Ethier, M C; Diorio, C; Martino, J; Mayo, C; Regier, D; Wing, R; Alibhai, S M H; Sung, L

2011-08-23

To describe (1) anticipated health-related quality of life during different strategies for febrile neutropaenia (FN) management and (2) attributes of those preferring inpatient management. Respondents were parents of children 0-18 years and children 12-18 years receiving cancer treatment. Anticipated health-related quality of life was elicited for four different FN management strategies: entire inpatient, early discharge, outpatient oral and outpatient intravenous (i.v.) therapy. Tools used to measure health-related quality of life were visual analogue scale (VAS), willingness to pay and time trade off. A total of 155 parents and 43 children participated. For parents, median VAS scores were highest for early discharge (5.9, interquartile range 4.4-7.2) and outpatient i.v. (5.9, interquartile range 4.4-7.3). For children, median scores were highest for early discharge (6.1, interquartile range 4.6-7.2). In contrast, the most commonly preferred strategy for parents and children was inpatient in 55.0% and 37.2%, respectively. Higher current child health-related quality of life was associated with a stronger preference for outpatient management. Early discharge and outpatient i.v. management are associated with higher anticipated health-related quality of life, although the most commonly preferred strategy was inpatient care. This data may help with determining more cost-effective strategies for paediatric FN.

Numerical simulations of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay, Indonesia.

PubMed

van der Wulp, Simon A; Damar, Ario; Ladwig, Norbert; Hesse, Karl-J

2016-09-30

The present application of numerical modelling techniques provides an overview of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay. A hydrological model simulated river discharges with a total of 90 to 377m(3)s(-1) entering Jakarta Bay. Daily total nitrogen and total phosphorus loads ranged from 40 to 174tons and 14 to 60tons, respectively. Flow model results indicate that nutrient gradients are subject to turbulent mixing by tides and advective transport through circulation driven by wind, barotropic and baroclinic pressure gradients. The bulk of nutrient loads originate from the Citarum and Cisadane rivers flowing through predominantly rural areas. Despite lower nutrient loads, river discharges from the urban area of Jakarta exhibit the highest impact of nutrient concentrations in the near shore area of Jakarta Bay and show that nutrient concentrations were not only regulated by nutrient loads but were strongly regulated by initial river concentrations and local flow characteristics. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Study on the discharge properties of xeon flash lamp and experimental measurement].

PubMed

Zhao, You-Quan; Miao, Pei-Liang; He, Feng; Gu, Jian; Zhai, Rui-Wei

2014-07-01

The Xenon flash lamp is a new type of light source for analytical instrument. The present paper analyzed the discharge process of xenon flash lamp, presented the discharge test system, and conducted experimental measurement of the voltage, current and optical pulse signal in the process of discharge. The results show that in the preliminary discharge, the free electron concentration was at a low level, so the energy was at a low level, then following the gas discharge, numerous free electrons formed in the lamp, resultin in the increase in the concentration of free electrons, therefore discharge current rised rapidly and voltage reduced. The lamp released photons to generate light pulse in the moment of ionic recombination, The pulse xenon lamp light energy output and spectral characteristic is related to electron energy in recombination and combination level of xenon, if the input energy and the energy consumption of the xenon lamp is inconsistent, it will lead to repeated capacitor charging and discharging and produce oscillation waveform. This paper is very useful for understanding the process of xenon lamp discharge, optimizing the driver circuit and the production of xenon flash lamp.

Current practice in continuous renal replacement therapy: An epidemiological multicenter study.

PubMed

Tomasa Irriguible, T M; Sabater Riera, J; Poch López de Briñas, E; Fort Ros, J; Lloret Cora, M J; Roca Antònio, J; Navas Pérez, A; Ortiz Ballujera, P; Servià Goixart, L; González de Molina Ortiz, F J; Rovira Anglès, C; Rodríguez López, M; Roglan Piqueras, A

2017-05-01

The aim of the study is to ascertain the most relevant aspects of the current management of renal replacement therapy (RRT) in critically ill patients, and to analyze renal function recovery and mortality in patients undergoing RRT. A non-interventional three-month observational study was made in 2012, with a follow-up period of 90 days, in 21 centers in Catalonia (Spain). Demographic information, severity scores and clinical data were obtained, as well as RRT parameters. patients aged ≥ 16 years admitted to Intensive Care Units (ICUs) and subjected to RRT. A total of 261 critically ill patients were recruited, of which 35% had renal dysfunction prior to admission. The main reason for starting RRT was oliguria; the most widely used RRT modality was hemodiafiltration; and the median prescribed dose at baseline was 35mL/kg/h. The median time of RRT onset from ICU admission was one day. The mortality rate at 30 and 90 days was 46% and 54%, respectively, and was associated to greater severity scores and a later onset of RRT. At discharge, 85% of the survivors had recovered renal function. Current practice in RRT in Catalonia abides with the current clinical practice guidelines. Mortality related to RRT is associated to later onset of such therapy. The renal function recovery rate at hospital discharge was 85% among the patients subjected to RRT. Copyright © 2016 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.

Characterization of SnO2/Ni/SiO2-MCP anode in three-dimensional lithium-ion battery

NASA Astrophysics Data System (ADS)

Lou, Xuefeng; Xu, Shaohui; Zhu, Yiping; Wang, Lianwei; Chu, Paul K.

2013-12-01

By combining a SnO2 thin film with silicon dioxide microchannel plate (SiO2-MCP), a three-dimensional (3D) structure with enough space to accommodate the volume change of SnO2 during charging-discharging is produced by MEMS and electroless deposition. Owing to the special structure of the MCP, the battery is able to deliver a reversible Li storage capacity of 408 mAhg-1 after 100 cycles. If the current density is reduced to 200 mAg-1 at a constant current during charging and discharging, the battery exhibits reversible capacities of 1575 and 996 mAhg-1 in the first discharging and charging cycle, respectively. However, a reversible Li-storage capacity of only 298 mAhg-1 is obtained after 50 cycles of deep charging at a current of 200 mAg-1. It is found that silicon is involved in the charging-discharging process at a low current.

Circuit analysis on the inductance evolution based on electrical signal from various type plasma focus device

NASA Astrophysics Data System (ADS)

Mohamad, Saiful Najmee; Ismail, Fairuz Diana; Noorden, Ahmad Fakhrurrazi Ahmad; Haider, Zuhaib; Ali, Jalil

2017-03-01

Numerous configurations of plasma focus devices (PFD) have been introduced around the globe. The distinct electrode configuration of the PFD will give out different inductance profile. A circuit analysis has been done to study on the significant difference between the inductance evolution in a coaxial discharge based on various published results of PFD. The discharge current signal, tube voltage and current derivative of the particular shots from distinct PFD was digitized and analyze. The investigation was piloted for three different types of PFD. It was observed that there is a significant difference for the normalize inductance profile during the discharge between the individual PFD with different electrode configuration. The depletion of the radial start current with the normalised inductance development for Mather type (PF-1000) is found to be 25.9% from static discharge. The current depletion continues to drop 1.1% and 1.3% more for a Spherical type (PNK-13) and Filippov type (PF-3) respectively.

A study of point discharge current observations in the thunderstorm environment at a tropical station during the year 1987 and 1988

NASA Technical Reports Server (NTRS)

Manohar, G. K.; Kandalgaonkar, S. S.; Sholapurkar, S. M.

1991-01-01

The results of the measurements of point discharge current observations at Pune, India, during years 1987 and 1988 are presented by categorizing and studying their number of spells, polar current average durations, and current magnitudes in day-time and night-time conditions. While the results showed that the thunderstorm activity occupies far more day-time than the night-time the level of current magnitudes remains nearly the same in the two categories.

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.

Optical Emission Characterization of High-Power Hall Thruster Wear

NASA Technical Reports Server (NTRS)

WIlliams, George J.; Kamhawi, Hani

2013-01-01

Optical emission spectroscopy is employed to correlate BN insulator erosion with high-power operation of the NASA 300M Hall-effect thruster. Actinometry leveraging excited xenon states is used to normalize the emission spectra of ground state boron as a function of thruster operating condition. Trends in the strength of the boron signal are correlated with thruster power, discharge voltage, discharge current and magnetic field strength. The boron signals are shown to trend with discharge current and show weak dependence on discharge voltage. The trends are consistent with data previously collected on the NASA 300M and NASA 457M thrusters but are different from conventional wisdom.

Laboratory facility for testing electric-vehicle batteries Test rig for simulating duty cycles with different discharge modes

NASA Astrophysics Data System (ADS)

Hamilton, J. A.; Rand, D. A. J.

1983-03-01

A test rig has been designed and constructed to examine the performance of batteries under laboratory conditions that simulate the power characteristics of electric vehicles. Each station in the rig subjects a battery to continuous charge/discharge cycles, with an equalising charge every eighth cycle. The battery discharge follows the current-verse-time profile of a given vehicle operating under a driving schedule normal to road service. The test rig allows both smooth- and pulsed-current discharge to be investigated. Data collection is accomplished either with multi-pen recorders or with a computer-based information logger.

Continuous tonic spike activity in spider warm cells in the absence of sensory input.

PubMed

Gingl, E; Tichy, H

2006-09-01

The warm cells of the spider tarsal organ respond very sensitively to low-amplitude changes in temperature and discharge continuously as the rate of change in temperature reaches zero. To test whether the continuous tonic discharge remains without sensory input, we blocked the warm cell's receptive region by Epoxy glue. The activity continued in this situation, but its dependence on temperature changes was strongly reduced. We interpret this to mean that the warm cells exhibit specific intrinsic properties that underlie the generation of the tonic discharge. Experiments with electrical stimulation confirmed the observation that the warm cells persist in activity without an external drive. In warm cells with blocked receptive region, the response curves describing the relationship between the tonic discharge and the level of depolarization is the same for different temperatures. In warm cells with intact receptive region, the curves are shifted upward with rising temperature, as if the injected current is simply added to the receptor current. This indicates a modulating effect of the receptor current on the tonic discharge. Stimulation causes a change in the tonic discharge rate and thereby enables individual warm cells to signal the direction in addition to the magnitude of temperature changes.

Coupling intensity between discharge and magnetic circuit in Hall thrusters

NASA Astrophysics Data System (ADS)

Wei, Liqiu; Yang, Xinyong; Ding, Yongjie; Yu, Daren; Zhang, Chaohai

2017-03-01

Coupling oscillation is a newly discovered plasma oscillation mode that utilizes the coupling between the discharge circuit and magnetic circuit, whose oscillation frequency spectrum ranges from several kilohertz to megahertz. The coupling coefficient parameter represents the intensity of coupling between the discharge and magnetic circuits. According to previous studies, the coupling coefficient is related to the material and the cross-sectional area of the magnetic coils, and the magnetic circuit of the Hall thruster. However, in our recent study on coupling oscillations, it was found that the Hall current equivalent position and radius have important effects on the coupling intensity between the discharge and magnetic circuits. This causes a difference in the coupling coefficient for different operating conditions of Hall thrusters. Through non-intrusive methods for measuring the Hall current equivalent radius and the axial position, it is found that with an increase in the discharge voltage and magnetic field intensity, the Hall current equivalent radius increases and its axial position moves towards the exit plane. Thus, both the coupling coefficient and the coupling intensity between the discharge and magnetic circuits increase. Contribution to the Topical Issue "Physics of Ion Beam Sources", edited by Holger Kersten and Horst Neumann.

Area scaling investigations of charging phenomena. [discharge pulse characteristics of Teflon thermal control tape

NASA Technical Reports Server (NTRS)

Aron, P. R.; Staskus, J. V.

1979-01-01

The charging and discharging behavior of square, planar samples of silvered, fluorinated ethylene-propylene (FEP) Teflon thermal control tape was measured. The equilibrium voltage profiles scaled with the width of the sample. A wide range of discharge pulse characteristics was observed, and the area dependences of the peak current, charge, and pulse widths are described. The observed scaling of the peak currents with area was weaker than that previously reported. The discharge parameters were observed to depend strongly on the grounding impedance and the beam voltage. Preliminary results suggest that measuring only the return-current-pulse characteristics is not adequate to describe the spacecraft discharging behavior of this material. The seams between strips of tape appear to play a fundamental role in determining the discharging behavior. An approximate propagation velocity for the charge cleanoff was extracted from the data. The samples - 232, 1265, and 5058 square centimeters in area - were exposed at ambient temperature to a 1- to 2-nA/sq cm electron beam at energies of 10, 15, and 20 kilovolts in a 19-meter-long by 4.6-meter-diameter simulation facility at the Lewis Research Center.

Experimental Investigation of Pseudospark generated electron beam

NASA Astrophysics Data System (ADS)

Kumar, Niraj; Verma, D. K.; Prajapati, J.; Kumar, M.; Meena, B. L.; Tyagi, M. S.; Srivastava, V.; Pal, U. N.

2012-11-01

The pseudospark (PS) discharge is, however, more recently recognized as a different type of discharge which is capable of generating electron beams with the highest combined current density and brightness of any known type of electron source. PS discharge is a specific type of gas discharge, which operates on the left-hand side of the hollow cathode analogy to the Paschen curve with axially symmetric parallel electrodes and central holes on the electrodes. The PS discharge generated electron beam has tremendous applications in plasma filled microwave sources where normal material cathode cannot be used. Analysis of the electron beam profile has been carried out experimentally for different applied voltages. The investigation has been done at different axial and radial location inside the drift tube in argon atmosphere. This paper represents experimentally derived axial and radial variation of the beam current inside the plasma filled drift tube of PS discharge based plasma cathode electron (PCE) gun. With the help of current density estimation the focusing and defocusing point of electron beam in axial direction can be analyzed. It has been further confirmed the successful propagation of electron beam in confined manner without any assistance of external magnetic field.

Pediatric procedural sedation with ketamine: time to discharge after intramuscular versus intravenous administration.

PubMed

Ramaswamy, Preeti; Babl, Franz E; Deasy, Conor; Sharwood, Lisa N

2009-02-01

Ketamine is an attractive agent for pediatric procedural sedation. There are limited data on time to discharge comparing intramuscular (IM) vs. intravenous (IV) ketamine. The authors set out to determine whether IM or IV ketamine leads to quicker discharge from the emergency department (ED) and how side effect profiles compare. All patients who had received ketamine IM or IV at a tertiary children's hospital ED during the 3-year study period (2004-2007) were identified. Prospective sedation registry data, retrospective medical records, and administrative data were reviewed for drug dosages, use of additional agents, time of drug administration to discharge, total ED time (triage to discharge), and adverse events. A subgroup analysis for patients requiring five or fewer sutures (short suture group) was performed. A total of 229 patients were enrolled (60% male) with median age of 2.8 years (IQR =1.8-4.3 years) and median weight of 15.7 kg (range = 8.7-74 kg). Ketamine was most frequently employed for laceration repair (80%) and foreign body removal (9%). Overall, 48% received ketamine IM and 52% received it IV. In the short-suture subgroup, 52% received ketamine IM, while 48% received it IV. Multivariate linear regression analysis determined time from drug administration to patient discharge as 21 minutes shorter for IV compared with IM administration, adjusted for age and number of additional doses (R(2) = -0.35; 95% CI = -0.5 to -0.19; p < 0.001). Total time in the ED (triage to discharge) comparing IV versus IM administration, adjusting for age and gender and number of additional doses, was not significantly different (p = 0.16). In the short-suture subgroup, time to discharge from administration was also shorter in the IV ketamine group (R(2) = -0.454; 95%CI = -0.66 to -0.25; p < 0.001) but similar for total time in ED (p = 0.16). Overall, adverse events occurred in 35% (95% CI = 27% to 45%) of the IM group and 20% (95% CI = 13% to 28%) of the IV group (p = 0.01). Only one patient required brief bag-mask ventilation. In this institution, time from drug injection to discharge was shorter in the IV compared to IM ketamine group, both overall and for the short-suture group. However, time from triage to discharge was similar.

State-of-charge coulometer

NASA Technical Reports Server (NTRS)

Rowlette, J. J. (Inventor)

1985-01-01

A coulometer for accurately measuring the state-of-charge of an open-cell battery utilizing an aqueous electrolyte, includes a current meter for measuring the battery/discharge current and a flow meter for measuring the rate at which the battery produces gas during charge and discharge. Coupled to the flow meter is gas analyzer which measures the oxygen fraction of the battery gas. The outputs of the current meter, flow meter, and gas analyzer are coupled to a programmed microcomputer which includes a CPU and program and data memories. The microcomputer calculates that fraction of charge and discharge current consumed in the generation of gas so that the actual state-of-charge can be determined. The state-of-charge is then shown on a visual display.

Testing and Analysis of NEXT Ion Engine Discharge Cathode Assembly Wear

NASA Technical Reports Server (NTRS)

Domonkos, Matthew T.; Foster, John E.; Soulas, George C.; Nakles, Michael

2003-01-01

Experimental and analytical investigations were conducted to predict the wear of the discharge cathode keeper in the NASA Evolutionary Xenon Thruster. The ion current to the keeper was found to be highly dependent upon the beam current, and the average beam current density was nearly identical to that of the NSTAR thruster for comparable beam current density. The ion current distribution was highly peaked toward the keeper orifice. A deterministic wear assessment predicted keeper orifice erosion to the same diameter as the cathode tube after processing 375 kg of xenon. A rough estimate of discharge cathode assembly life limit due to sputtering indicated that the current design exceeds the qualification goal of 405 kg. Probabilistic wear analysis showed that the plasma potential and the sputter yield contributed most to the uncertainty in the wear assessment. It was recommended that fundamental experimental and modeling efforts focus on accurately describing the plasma potential and the sputtering yield.

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

The current-density distribution in a pulsed dc magnetron deposition discharge

NASA Astrophysics Data System (ADS)

Vetushka, Alena; Bradley, James W.

2007-04-01

Using a carefully constructed magnetic probe (a B-dot probe) the spatial and temporal evolution of the perturbation in the magnetic field ΔB in an unbalanced pulsed dc magnetron has been determined. The plasma was run in argon at a pressure of 0.74 Pa and the plasma ions sputtered a pure graphite target. The pulse frequency and duty were set at 100 kHz and 55%, respectively. From the ΔB measurements (measured with magnitudes up to about 0.01 mT) the axial, azimuthal and radial components of the total current density j in the plasma bulk were determined. In the plasma 'on' phase, the axial current density jz has a maximum value of approximately 200 A m-2 above the racetrack region, while high values in the azimuthal current density jΦ are distributed in a region from 1 to 3 cm into the bulk plasma with jΦ exceeding 350 A m-2. In the 'off' phase of the plasma, jz decays almost instantaneously (at least within the 100 ns time-resolution of the ΔB measurements) as the electric field collapses; however, jΦ decays with a characteristic time constant of about 1 µs. This slow decay can be attributed to the presence of decaying Grad-B and curvature drifts, with their rates controlled by the decay in the plasma density. A comparison between axial and azimuthal current densities in the plasma 'on' time, when the plasma is being driven, strongly indicates that classical transport does not operate in the magnetron discharge.

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

Lightning propagation and flash density in squall lines as determined with radar

NASA Technical Reports Server (NTRS)

Mazur, V.; Rust, W. D.

1983-01-01

Lightning echo rise times and range-time variations due to discharge propagation are determined using S and L band radars, and the evolution of precipitation reflectivity and the associated lightning activity in squall lines is investigated using VHF and L band radars. The rise time of radar echoes can be explained by ionized channel propagation through the radar beams. Speeds of at least 250,000 m/s are found from measurements of the radial velocity of streamer propagation along the antenna beam. The range-time variations in lightning echoes indicate that either new ionization occurs as streamers develop into different parts of the cloud, channel delay occurs during which adequate ionization exists for radar detection, or continuing current occurs. Determinations of the lightning flash density for a squall line in the U.S. show that the maximum lightning density tends to be near the leading edge of the precipitation cores in developing cells. Long discharges are produced as a cell in the squall line develops and the total lightning density increases, although short discharges predominate. As the cell dissipates, short flashes diminish or cease and the long flashes dominate the lightning activity.

Electric discharge during electrosurgery

PubMed Central

Shashurin, Alexey; Scott, David; Zhuang, Taisen; Canady, Jerome; Beilis, Isak I.; Keidar, Michael

2015-01-01

Electric discharge utilized for electrosurgery is studied by means of a recently developed method for the diagnostics of small-size atmospheric plasma objects based on Rayleigh scattering of microwaves on the plasma volume. Evolution of the plasma parameters in the near-electrode sheaths and in the positive column is measured and analyzed. It is found that the electrosurgical system produces a glow discharge of alternating current with strongly contracted positive column with current densities reaching 103 A/cm2. The plasma electron density and electrical conductivities in the channel were found be 1016 cm−3 and (1-2) Ohm−1cm−1, respectively. The discharge interrupts every instance when the discharge-driving AC voltage crosses zero and re-ignites again every next half-wave at the moment when the instant voltage exceeds the breakdown threshold. PMID:25880721

Electric discharge during electrosurgery.

PubMed

Shashurin, Alexey; Scott, David; Zhuang, Taisen; Canady, Jerome; Beilis, Isak I; Keidar, Michael

2015-04-16

Electric discharge utilized for electrosurgery is studied by means of a recently developed method for the diagnostics of small-size atmospheric plasma objects based on Rayleigh scattering of microwaves on the plasma volume. Evolution of the plasma parameters in the near-electrode sheaths and in the positive column is measured and analyzed. It is found that the electrosurgical system produces a glow discharge of alternating current with strongly contracted positive column with current densities reaching 10(3) A/cm(2). The plasma electron density and electrical conductivities in the channel were found be 10(16) cm(-3) and (1-2) Ohm(-1) cm(-1), respectively. The discharge interrupts every instance when the discharge-driving AC voltage crosses zero and re-ignites again every next half-wave at the moment when the instant voltage exceeds the breakdown threshold.

Electron-Impact-Ionization and Electron-Attachment Cross Sections of Radicals Important in Transient Gaseous Discharges.

DTIC Science & Technology

1988-02-05

for understanding the microscopic processes of electrical discharges and for designing gaseous discharge switches. High power gaseous discharge switches...half-maximum) energy resolution. The electron gun and ion extraction were of the same design of Srivastava at the Jet Propulsion Laboratory. Ions...photons. - The observed current switching can be applied to the design of discharge switches. Elec- tron transport parameters are needed for the

Plasma Diagnostics For The Investigation of Silane Based Glow Discharge Deposition Processes

NASA Astrophysics Data System (ADS)

Mataras, Dimitrios

2001-10-01

In this work is presented the study of microcrystalline silicon PECVD process through highly diluted silane in hydrogen discharges. The investigation is performed by applying different non intrusive plasma diagnostics (electrical, optical, mass spectrometric and laser interferometric measurements). Each of these measurements is related to different plasma sub-processes (gas physics, plasma chemistry and plasma surface interaction) and compose a complete set, proper for the investigation of the effect of external discharge parameters on the deposition processes. In the specific case these plasma diagnostics are applied for prospecting the optimal experimental conditions from the ic-Si:H deposition rate point of view. Namely, the main characteristics of the effect of frequency, discharge geometry, power consumption and total gas pressure on the deposition process are presented successively. Special attention is given to the study of the frequency effect (13.56 MHz 50 MHz) indicating that the correct way to compare results of different driving frequency discharges is by maintaining constant the total power dissipation in the discharge. The important role of frequency in the achievement of high deposition rates and on the optimization of all other parameters is underlined. Finally, the proper combination of experimental conditions that result from the optimal choice of each of the above-mentioned discharge parameters and lead to high microcrystalline silicon deposition rates (7.5 Å/sec) is presented. The increase of silane dissociation rate towards neutral radicals (frequency effect), the contribution of highly sticking to the surface radicals (discharge geometry optimum) and the controlled production of higher radicals through secondary gas phase reactions (total gas pressure), are presented as prerequisites for the achievement of high deposition rates.

Zn/gelled 6 M KOH/O 2 zinc-air battery

NASA Astrophysics Data System (ADS)

Mohamad, A. A.

The gel electrolyte for the zinc-air cell was prepared by mixing hydroponics gel with a 6 M potassium hydroxide aqueous solution. The self-discharge of cells was characterized by measuring the open-circuit voltage. The effect of a discharge rate of 50 mA constant current on cell voltage and plateau hour, as well as the voltage-current and current density-power density were measured and analysed. The electrode degradation after discharge cycling was characterized by structural and surface methods. The oxidation of the electrode surface further blocked the utilization of the Zn anode and was identified as a cause for the failure of the cell.

State Firearm Legislation and Nonfatal Firearm Injuries.

PubMed

Simonetti, Joseph A; Rowhani-Rahbar, Ali; Mills, Brianna; Young, Bessie; Rivara, Frederick P

2015-08-01

We investigated whether stricter state-level firearm legislation was associated with lower hospital discharge rates for nonfatal firearm injuries. We estimated discharge rates for hospitalized and emergency department-treated nonfatal firearm injuries in 18 states in 2010 and used negative binomial regression to determine whether strength of state firearm legislation was independently associated with total nonfatal firearm injury discharge rates. We identified 26 744 discharges for nonfatal firearm injuries. The overall age-adjusted discharge rate was 19.0 per 100 000 person-years (state range = 3.3-36.6), including 7.9 and 11.1 discharges per 100 000 for hospitalized and emergency department-treated injuries, respectively. In models adjusting for differences in state sociodemographic characteristics and economic conditions, states in the strictest tertile of legislative strength had lower discharge rates for total (incidence rate ratio [IRR] = 0.60; 95% confidence interval [CI] = 0.44, 0.82), assault-related (IRR = 0.58; 95% CI = 0.34, 0.99), self-inflicted (IRR = 0.18; 95% CI = 0.14, 0.24), and unintentional (IRR = 0.53; 95% CI = 0.34, 0.84) nonfatal firearm injuries. There is significant variation in state-level hospital discharge rates for nonfatal firearm injuries, and stricter state firearm legislation is associated with lower discharge rates for such injuries.

State Firearm Legislation and Nonfatal Firearm Injuries

PubMed Central

Rowhani-Rahbar, Ali; Mills, Brianna; Young, Bessie; Rivara, Frederick P.

2015-01-01

Objectives. We investigated whether stricter state-level firearm legislation was associated with lower hospital discharge rates for nonfatal firearm injuries. Methods. We estimated discharge rates for hospitalized and emergency department–treated nonfatal firearm injuries in 18 states in 2010 and used negative binomial regression to determine whether strength of state firearm legislation was independently associated with total nonfatal firearm injury discharge rates. Results. We identified 26 744 discharges for nonfatal firearm injuries. The overall age-adjusted discharge rate was 19.0 per 100 000 person-years (state range = 3.3–36.6), including 7.9 and 11.1 discharges per 100 000 for hospitalized and emergency department–treated injuries, respectively. In models adjusting for differences in state sociodemographic characteristics and economic conditions, states in the strictest tertile of legislative strength had lower discharge rates for total (incidence rate ratio [IRR] = 0.60; 95% confidence interval [CI] = 0.44, 0.82), assault-related (IRR = 0.58; 95% CI = 0.34, 0.99), self-inflicted (IRR = 0.18; 95% CI = 0.14, 0.24), and unintentional (IRR = 0.53; 95% CI = 0.34, 0.84) nonfatal firearm injuries. Conclusions. There is significant variation in state-level hospital discharge rates for nonfatal firearm injuries, and stricter state firearm legislation is associated with lower discharge rates for such injuries. PMID:26066935

Temporal variability in stage-discharge relationships

NASA Astrophysics Data System (ADS)

Guerrero, José-Luis; Westerberg, Ida K.; Halldin, Sven; Xu, Chong-Yu; Lundin, Lars-Christer

2012-06-01

SummaryAlthough discharge estimations are central for water management and hydropower, there are few studies on the variability and uncertainty of their basis; deriving discharge from stage heights through the use of a rating curve that depends on riverbed geometry. A large fraction of the world's river-discharge stations are presumably located in alluvial channels where riverbed characteristics may change over time because of erosion and sedimentation. This study was conducted to analyse and quantify the dynamic relationship between stage and discharge and to determine to what degree currently used methods are able to account for such variability. The study was carried out for six hydrometric stations in the upper Choluteca River basin, Honduras, where a set of unusually frequent stage-discharge data are available. The temporal variability and the uncertainty of the rating curve and its parameters were analysed through a Monte Carlo (MC) analysis on a moving window of data using the Generalised Likelihood Uncertainty Estimation (GLUE) methodology. Acceptable ranges for the values of the rating-curve parameters were determined from riverbed surveys at the six stations, and the sampling space was constrained according to those ranges, using three-dimensional alpha shapes. Temporal variability was analysed in three ways: (i) with annually updated rating curves (simulating Honduran practices), (ii) a rating curve for each time window, and (iii) a smoothed, continuous dynamic rating curve derived from the MC analysis. The temporal variability of the rating parameters translated into a high rating-curve variability. The variability could turn out as increasing or decreasing trends and/or cyclic behaviour. There was a tendency at all stations to a seasonal variability. The discharge at a given stage could vary by a factor of two or more. The quotient in discharge volumes estimated from dynamic and static rating curves varied between 0.5 and 1.5. The difference between discharge volumes derived from static and dynamic curves was largest for sub-daily ratings but stayed large also for monthly and yearly totals. The relative uncertainty was largest for low flows but it was considerable also for intermediate and large flows. The standard procedure of adjusting rating curves when calculated and observed discharge differ by more than 5% would have required continuously updated rating curves at the studied locations. We believe that these findings can be applicable to many other discharge stations around the globe.

Association of insurance status and spinal fusion usage in the United States during two decades.

PubMed

John, Jason; Mirahmadizadeh, Alireza; Seifi, Ali

2018-05-01

This study examined the distribution of spinal fusion usage among payer groups in the United States. Using the National Inpatient Sample (NIS) database, total discharges, length of stay, and mean hospital charges of patients who underwent spinal fusion from 1997 to 2014 in the United States were determined and analyzed. 5,715,625 total discharges with spinal fusion were reported. Among them, 2,875,188 (50.3%) were covered by private insurance, 1,710,182 by Medicare (29.9%), 342,638 (6.0%) by Medicaid, and 91,990 (1.6%) were uninsured. A statistically significant increase in spinal fusion usage occurred within each payer group over the study period (P < 0.001). For every year of the study period, private insurance patients had the most number and uninsured patients had the least number of total discharges with spinal fusion. Furthermore, annual growth in spinal fusion usage was greatest among private insurance patients, and smallest among uninsured patients. Total discharges with spinal fusion increased significantly across all payer groups between 1997 and 2014, but not equally. Further inquiry is indicated to determine the etiology of spinal fusion usage discrepancies between payer groups. Copyright © 2018 Elsevier Ltd. All rights reserved.

Preliminary Measurement of Electromagnetic Fields and Microdischarges From the Human Body.

PubMed

Zheng, Ying; Zhang, Houqi; Yip, Karr; Zheng, Zhen; Yang, Shiji

2016-01-01

From 1978-1999, a large number of experts and scholars in China tested and analyzed the external qi of qigong (ie, the electrical signals [ES] released from human practitioners). Development of negatives from some tests had revealed the existence of speckles on the films. In 1998, the current research team analyzed some of the negatives that had been exposed to the ES. The current research team intended to test for the presence of ES in qigong using the dielectric-barrier discharge (DBD) method. The study design involved 2 measurements: electromagnetic test of a open, placebo-controlled methodology and an optical test of single-blinded open, placebo-controlled methodology. The study occurred in Taiyuan, Suzhou, and Shenzhen (China) as well as in Hong Kong. Participants were 10 qigong masters and practitioners and 5 nonpractitioners from 4 cities. In the ES test, the practitioners released ES and the nonpractitioners simulated the release of ES, using 2 channels. Any ambient disturbance was recorded on both channels. For the photo file, the practitioner or nonpractitioner could press his or her palm onto 1 envelope that contained film or could hold his or her palm a certain distance (5-30 cm) above the envelope to release ES or simulate its release, respectively. An oscilloscope, current probes, and photo negatives were used to acquire >50,000 images. A type of discharged electromagnetic field (EMF), with a frequency of approximately 0.3-200 MHz, was recorded. The microdischarge pulses were positive, with a pulse width from 2-100 ns and with a total charge of approximately 0.001-0.2 nC. Many speckles could also be clearly seen in the photo negatives. Within the context of DBD theory, the speckles could be individual footprints of a barrier discharge for which the human skin acts as a barrier layer. Thus, the study measured reproducible field energy or an EMF and microdischarges. ES were measured; then EMFs with a frequency of approximately 0.3-200 MHz and microdischarge pulses were recorded. Within the context of DBD theory, those results suggest that the microdischarge may act as a barrier discharge to which the human skin forms a barrier layer.

Costs Associated With Access Site and Same-Day Discharge Among Medicare Beneficiaries Undergoing Percutaneous Coronary Intervention: An Evaluation of the Current Percutaneous Coronary Intervention Care Pathways in the United States.

PubMed

Amin, Amit P; Patterson, Mark; House, John A; Giersiefen, Helmut; Spertus, John A; Baklanov, Dmitri V; Chhatriwalla, Adnan K; Safley, David M; Cohen, David J; Rao, Sunil V; Marso, Steven P

2017-02-27

The aim of this study was to examine the independent impact of various care pathways, including those involving transradial intervention (TRI) and same-day discharge (SDD) after elective percutaneous coronary intervention (PCI), on hospital costs. PCI is associated with costs of $10 billion annually. Alternative payment models for PCI are being implemented, but few data exist on strategies to reduce costs. Various PCI care pathways, including TRI and SDD, exist, but their association with costs and outcomes is unknown. In total, 279,987 PCI patients eligible for SDD in the National Cardiovascular Data Registry CathPCI Registry linked to Medicare claims files were analyzed. Hospital costs in 2014 U.S. dollars were estimated using cost-to-charge ratios. Propensity scores for TRI and SDD, with propensity adjustment via inverse probability weighting, was performed. Of the 279,987 PCI procedures, TRI was used in 9.0% (13.5% of which were SDD), and SDD was used in 5.3% of cases (23.1% of which were TRI). TRI (vs. transfemoral intervention) was associated with lower adjusted costs of $916 (95% confidence interval [CI]: $778 to $1,035), as was SDD ($3,502; 95% CI: $3,486 to $3,902). The adjusted cost associated with TRI and SDD was $13,389 (95% CI: $13,161 to $13,607), while the cost associated with transfemoral intervention and non-same-day discharge was $17,076 (95% CI: $16,999 to $17,147), a difference of $3,689 (95% CI: $3,486 to $3,902; p < 0.0001). Shifting current practice from transfemoral intervention non-same-day discharge to TRI SDD by 30% could potentially save a hospital performing 1,000 PCIs each year $1 million and the country $300 million annually. Among Medicare beneficiaries, TRI with SDD was independently associated with fewer complications and lower in-hospital costs. These findings have important implications for changing the current PCI care pathways to improve outcomes and reduce costs. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Influence of different gaps among the split targets with gradient potential to the discharge effects generated by hypervelocity impact

NASA Astrophysics Data System (ADS)

Tang, Enling; Zhao, Liangliang; Han, Yafei; Zhang, Qingming; Wang, Ruizhi; He, Liping; Liu, Shuhua

2018-04-01

Due to the actual situation of spacecraft surface' charging, such as convex corners, weld line, whalebone and a multiple-interfaces with different materials, all these are main factors leading to uneven charging of spacecraft surface, even creating gradient potential. If the charging spacecraft surface is impacted by debris or micrometeor, discharge effect induced by impacting will pose a serious threat to spacecraft in orbit. So realizing spacecraft charging surface with different potential differences and grasping discharge characteristics are a decisive importance at the different experimental conditions in laboratory. To simulate the spacecraft surface with a gradient potential in laboratory, spacecraft surface is split into different parts, which different gaps reserved in 2 adjacent surface is added resistance to create different potential surfaces, and the high potential surface as a impact target in the split targets. Charging circuit system realizing different gradient potential and discharge test system are built by ourselves, combining with two-stage light gas gun loading system, six sets of experiments have been performed about hypervelocity impact on 2A12 aluminum split targets with gradient potentials. In the experiments, gaps of 2A12 aluminum target are the same among different parts in every experiments, the gaps of the split targets are 2mm, 3mm, 5mm, 7mm and 10mm in the experiments, respectively. And the applied voltage is 300V in all the experiments and high-potential 2A12 aluminum plate as the impact target. The experiments have been performed at the impact velocity of about 3km/s and the incidence angles of 60o and 90o (between projectile flying trajectory and target plane), respectively. Voltage probe and current probes are used for acquiring discharge voltages and currents during the process of the impact. The experimental results showed that the discharge induced by impact plasma were generated among high and low-potential target by forming a plasma discharge channel. With the increasing of the gaps among the high and low-potential targets, the peak values of the discharge current decreased first then increased. When the gaps of split targets reached a certain value, the peak values of the discharge current decreased again. Meanwhile, the gaps among high and low-potential targets was 5mm, the peak value of the discharge current was the smallest. With the increasing of the gaps among the split targets, a primary discharge duration also increased. However, when the gaps among the split targets were greater than 5mm, increasing trend of discharge duration would slow down. When the gaps among the split targets were greater than 7mm, there was a secondary discharge phenomenon, and the physical explanations were given about the influence of different gaps among the split targets on the discharge effects created by hypervelocity impact.

Ultraviolet Rayleigh Scatter Imaging for Spatial Temperature Profiles in Atmospheric Microdischarges

DTIC Science & Technology

2014-09-01

regime and not in a neighboring regime such as an abnormal glow or a corona discharge . As discussed in section 3.1, unlike abnormal discharges or... coronas , normal glows have a voltage drop that is independent of discharge current for several orders of magnitude, which would manifest itself...5 3.2 Discharge Power and Gas Temperature

Response of lead-acid batteries to chopper-controlled discharge. [for electric vehicles

NASA Technical Reports Server (NTRS)

Cataldo, R. L.

1978-01-01

The results of tests on an electric vehicle battery, using a simulated electric vehicle chopper-speed controller, show energy output losses up to 25 percent compared to constant current discharges at the same average current of 100 A. However, an energy output increase of 22 percent is noticed at the 200 A average level and 44 percent increase at the 300 A level using pulse discharging. Because of these complex results, electric vehicle battery/speed controller interactions must be considered in vehicle design.

Liposomal Bupivacaine Suspension Can Reduce Lengths of Stay and Improve Discharge Status of Patients Undergoing Total Knee Arthroplasty.

PubMed

Chughtai, Morad; Cherian, Jeffrey Jai; Mistry, Jaydev B; Elmallah, Randa D K; Bennett, Alicia; Mont, Michael A

2016-04-01

The purpose of this study was to use a large hospital database to assess: (1) length of hospital stay (LOS) and (2) discharge status among patients undergoing total knee arthroplasty (TKA) with or without the use of a liposomal bupivacaine suspension injection. We utilized an all-payer hospital administrative database from July 1, 2013 to June 30, 2014. We then selected patients age 18 years or older who had an inpatient stay for TKA in the data window based on International Classification of Diseases, Ninth Revision (ICD-9) procedure codes (ICD-9-CM = 81.54), which resulted in 103,152 TKA patients. Patients who had nerve blocks were excluded, which resulted in 94,828 TKA patients. The TKA cohort who received a liposomal bupivacaine suspension consisted of 14,668 patients (9,211 females; 5,457 males) who had a mean age of 66 years, while the TKAs without injections or block consisted of 80,160 patients (49,699 females; 30,461 males) who had a mean age of 66 years. Analyses of LOS were performed using a linear model, controlling for age, sex, race, region, Charlson index, and operating time. Discharge status to home versus rehabilitation or short-term nursing facility was evaluated using logistic regression analysis controlling for the above covariates. The adjusted mean LOS for the injection cohort was significantly shorter at 2.58 days compared with 2.98 days in the no injection cohort. The unadjusted distribution of patients being discharged to home compared with short-term nursing facility or rehabilitation was higher in the injection cohort compared with the cohort who did not receive injections (73.2 vs. 66.6%). Logistic regression analysis demonstrated that there was a higher likelihood of being discharged to home with liposomal bupivacaine. Patients who underwent TKA with liposomal bupivacaine had a significantly shorter LOS and a higher likelihood of being discharged to home. These results suggest that liposomal bupivacaine may represent a promising addition to current pain management regimens. Furthermore, it may limit pain following surgery, which may allow patients to ambulate earlier and have improved outcomes. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Application of acoustical methods for estimating water flow and constituent loads in Perdido Bay, Florida

USGS Publications Warehouse

Grubbs, J.W.; Pittman, J.R.

1997-01-01

Water flow and quality data were collected from December 1994 to September 1995 to evaluate variations in discharge, water quality, and chemical fluxes (loads) through Perdido Bay, Florida. Data were collected at a cross section parallel to the U.S. Highway 98 bridge. Discharges measured with an acoustic Doppler current profiler (ADCP) and computed from stage-area and velocity ratings varied roughly between + or - 10,000 cubic feet per second during a typical tidal cycle. Large reversals in flow direction occurred rapidly (less than 1 hour), and complete reversals (resulting in near peak net-upstream or downstream discharges) occurred within a few hours of slack water. Observations of simultaneous upstream and downstream flow (bidirectional flow) were quite common in the ADCP measurements, with opposing directions of flow occurring predominantly in vertical layers. Continuous (every 15 minutes) discharge data were computed for the period from August 18, 1995, to September 28, 1995, and filtered daily mean discharge values were computed for the period from August 19 to September 26, 1995. Data were not computed prior to August 18, 1995, either because of missing data or because the velocity rating was poorly defined (because of insufficient data) for the period prior to landfall of hurricane Erin (August 3, 1995). The results of the study indicate that acoustical techniques can yield useful estimates of continuous (instantaneous) discharge in Perdido Bay. Useful estimates of average daily net flow rates can also be obtained, but the accuracy of these estimates will be limited by small rating shifts that introduce bias into the instantaneous values that are used to compute the net flows. Instantaneous loads of total nitrogen ranged from -180 to 220 grams per second for the samples collected during the study, and instantaneous loads of total phosphorous ranged from -10 to 11 grams per second (negative loads indicate net upstream transport). The chloride concentrations from the water samples collected from Perdido Bay indicated a significant amount of mixing of saltwater and freshwater. Mixing effects could greatly reduce the accuracy of estimates of net loads of nutrients or other substances. The study results indicate that acoustical techniques can yield acceptable estimates of instantaneous loads in Perdido Bay. However, estimates of net loads should be interpreted with great caution and may have unacceptably large errors, especially when saltwater and freshwater concentrations differ greatly.

"I have nine specialists. They need to swap notes!" Australian patients' perspectives of medication-related problems following discharge from hospital.

PubMed

Eassey, Daniela; McLachlan, Andrew J; Brien, Jo-Anne; Krass, Ines; Smith, Lorraine

2017-10-01

Research has shown that patients are most susceptible to medication-related problems (MRPs) when transitioning from hospital to home. Currently, the literature in this area focuses on interventions, which are mainly orientated around the perspective of the health-care professional and do not take into account patient perspectives and experiences. To capture the experiences and perceptions of Australian patients regarding MRPs following discharge from hospital. A cross-sectional study was conducted using a questionnaire collecting quantitative and qualitative data. Thematic analysis was conducted of the qualitative data. Survey participants were recruited through The Digital Edge, an online market research company. Five hundred and six participants completed the survey. A total of 174 participants self-reported MRPs. Two concepts and seven subthemes emerged from the analysis. The first concept was types of MRPs and patient experiences. Three themes were identified: unwanted effects from medicines, confusion about medicines and unrecognized medicines. The second concept was patient engagement in medication management, of which four themes emerged: informing patients, patient engagement, communication amongst health-care professionals and conflicting advice. This study provides an important insight into patients' experiences and perceptions of MRPs following discharge from hospital. Future direction for practice and research should look into implementing patient-centred care at the time of hospital discharge to ensure the provision of clear and consistent information, and developing ways to support and empower patients to ensure a smooth transition post-discharge from hospital. © 2017 The Authors Health Expectations Published by John Wiley & Sons Ltd.

Managing risk during care transitions when approaching end of life: A qualitative study of patients' and health care professionals' decision making.

PubMed

Coombs, Maureen A; Parker, Roses; de Vries, Kay

2017-07-01

Increasing importance is being placed on the coordination of services at the end of life. To describe decision-making processes that influence transitions in care when approaching the end of life. Qualitative study using field observations and longitudinal semi-structured interviews. Field observations were undertaken in three sites: a residential care home, a medical assessment unit and a general medical unit in New Zealand. The Supportive and Palliative Care Indicators Tool was used to identify participants with advanced and progressive illness. Patients and family members were interviewed on recruitment and 3-4 months later. Four weeks of fieldwork were conducted in each site. A total of 40 interviews were conducted: 29 initial interviews and 11 follow-up interviews. Thematic analysis was undertaken. Managing risk was an important factor that influenced transitions in care. Patients and health care staff held different perspectives on how such risks were managed. At home, patients tolerated increasing risk and used specific support measures to manage often escalating health and social problems. In contrast, decisions about discharge in hospital were driven by hospital staff who were risk-adverse. Availability of community and carer services supported risk management while a perceived need for early discharge decision making in hospital and making 'safe' discharge options informed hospital discharge decisions. While managing risk is an important factor during care transitions, patients should be able to make choices on how to live with risk at the end of life. This requires reconsideration of transitional care and current discharge planning processes at the end of life.

A Hybrid Semi-Digital Transimpedance Amplifier With Noise Cancellation Technique for Nanopore-Based DNA Sequencing.

PubMed

Hsu, Chung-Lun; Jiang, Haowei; Venkatesh, A G; Hall, Drew A

2015-10-01

Over the past two decades, nanopores have been a promising technology for next generation deoxyribonucleic acid (DNA) sequencing. Here, we present a hybrid semi-digital transimpedance amplifier (HSD-TIA) to sense the minute current signatures introduced by single-stranded DNA (ssDNA) translocating through a nanopore, while discharging the baseline current using a semi-digital feedback loop. The amplifier achieves fast settling by adaptively tuning a DC compensation current when a step input is detected. A noise cancellation technique reduces the total input-referred current noise caused by the parasitic input capacitance. Measurement results show the performance of the amplifier with 31.6 M Ω mid-band gain, 950 kHz bandwidth, and 8.5 fA/ √Hz input-referred current noise, a 2× noise reduction due to the noise cancellation technique. The settling response is demonstrated by observing the insertion of a protein nanopore in a lipid bilayer. Using the nanopore, the HSD-TIA was able to measure ssDNA translocation events.

Electrostatic Discharge Testing of Carbon Composite Solar Array Panels for Use in the Jovian Environment

NASA Technical Reports Server (NTRS)

Green, Nelson W.; Dawson, Stephen F.

2015-01-01

NASA is currently considering a mission to investigate the moons of Jupiter. When designing a spacecraft for this type of mission, there are a number of engineering challenges, especially if the mission chooses to utilize solar arrays to provide the spacecraft power. In order for solar arrays to be feasible for the mission, their total mass needed to fit within the total budget for the mission, which strongly suggested the use of carbon composite facesheets on an aluminum core for the panel structure. While these composite structures are a good functional substitution for the metallic materials they replace, they present unique challenges when interacting with the harsh Jovian space environment. As a composite material, they are composed of more than one material and can show different base properties depending in differing conditions. Looking at the electrical properties, in an Earth-based environment the carbon component of the composite dominates the response of the material to external stimulus. Under these conditions, the structures strongly resembles a conductor. In the Jovian environment, with temperatures reaching 50K and under the bombardment from energetic electrons, the non-conducting pre-preg binding materials may come to the forefront and change the perceived response. Before selecting solar arrays as the baseline power source for a mission to Jupiter, the response of the carbon composites to energetic electrons while held at cryogenic temperatures needed to be determined. A series of tests were devised to exam the response of a sample solar array panel composed of an M55J carbon weave layup with an RS-3 pre-preg binder. Test coupons were fabricated and exposed to electrons ranging from 10 keV to 100 keV, at 1 nA/cm2, while being held at cryogenic temperatures. While under electron bombardment, electrical discharges were observed and recorded with the majority of discharges occurring with electron energies of 25 keV. A decrease in temperature to liquid nitrogen temperatures showed a marked increase in the magnitude of these discharges. The results indicate that dielectric discharges are primarily produced due to the presence of large regions of the non-conductive pre-preg on the surface of the carbon sheets. The frequency and magnitude of discharges decreased when layers of the pre-preg material were removed from the composite surface. These tests indicate that solar array panels may be used in the Jovian environment, but that electrostatic discharges can be expected on the carbon composite solar arrays.

SynCardia Portable Freedom Driver: A Single-Center Experience With 11 Patients.

PubMed

Shah, Nilay R; Jaroszewski, Dawn E; Ashfaq, Awais; Schroedl, Lucas A; Staley, Linda L; Pajaro, Octavio E; Kasirajan, Vigneshwar; Arabia, Francisco A

2015-01-01

The portable Freedom Drive (SynCardia Inc, Tucson, AZ USA) for total artificial heart (TAH-t) support was approved for an investigational device exemption study in March 2010. We review our center's experience with the portable driver. A retrospective review was conducted of patients who underwent TAH-t implantation and transfer to portable driver from September 2008 to June 2012, with follow-up through December 2012. A total of 30 patients underwent TAH-t implantation during this time period, with 11 patients successfully transferred to the Freedom Driver. Transfer to Freedom Driver after TAH-t implant was a median of 46 days (range, 225-86 days). Ninety-one percent (10) of 11 patients transferred to Freedom Driver were bridged to transplantation. One patient died on support. Five (45.5%) of 11 patients were discharged home and 5 (45.5%) remained in-patient on the portable driver before transplantation. Four patients (80%) successfully discharged home required at least 1 hospital readmission (range, 1-5 admissions per patient). Six patients (55%) transferred to the portable driver required a return to a main driver console. Two patients were temporarily maintained on the main driver then returned to the Freedom Driver for bridge to transplantation. Patients with TAH-t can be considered for transfer to the portable Freedom Driver while awaiting transplantation. Issues that complicated this patient population included inadequate social support, hemodynamic instability, and concurrent morbidities. The potential benefits of the portable driver are currently undergoing assessment. These may include increased mobility and improved quality of life, opportunity for discharge home, and decreased overall medical costs.

Nutrient Loads Flowing into Coastal Waters from the Main Rivers of China (2006–2012)

PubMed Central

Tong, Yindong; Zhao, Yue; Zhen, Gengchong; Chi, Jie; Liu, Xianhua; Lu, Yiren; Wang, Xuejun; Yao, Ruihua; Chen, Junyue; Zhang, Wei

2015-01-01

Based on monthly monitoring data of unfiltered water, the nutrient discharges of the eight main rivers flowing into the coastal waters of China were calculated from 2006 to 2012. In 2012, the total load of NH3-N (calculated in nitrogen), total nitrogen (TN, calculated in nitrogen) and total phosphorus (TP, calculated in phosphorus) was 5.1 × 105, 3.1 × 106 and 2.8 × 105 tons, respectively, while in 2006, the nutrient load was 7.4 × 105, 2.2 × 106 and 1.6 × 105 tons, respectively. The nutrient loading from the eight major rivers into the coastal waters peaked in summer and autumn, probably due to the large water discharge in the wet season. The Yangtze River was the largest riverine nutrient source for the coastal waters, contributing 48% of the NH3-N discharges, 66% of the TN discharges and 84% of the TP discharges of the eight major rivers in 2012. The East China Sea received the majority of the nutrient discharges, i.e. 50% of NH3-N (2.7 × 105 tons), 70% of TN (2.2 × 106 tons) and 87% of TP (2.5 × 105 tons) in 2012. The riverine discharge of TN into the Yellow Sea and Bohai Sea was lower than that from the direct atmospheric deposition, while for the East China Sea, the riverine TN input was larger. PMID:26582206

Nutrient Loads Flowing into Coastal Waters from the Main Rivers of China (2006-2012).

PubMed

Tong, Yindong; Zhao, Yue; Zhen, Gengchong; Chi, Jie; Liu, Xianhua; Lu, Yiren; Wang, Xuejun; Yao, Ruihua; Chen, Junyue; Zhang, Wei

2015-11-19

Based on monthly monitoring data of unfiltered water, the nutrient discharges of the eight main rivers flowing into the coastal waters of China were calculated from 2006 to 2012. In 2012, the total load of NH3-N (calculated in nitrogen), total nitrogen (TN, calculated in nitrogen) and total phosphorus (TP, calculated in phosphorus) was 5.1 × 10(5), 3.1 × 10(6) and 2.8 × 10(5) tons, respectively, while in 2006, the nutrient load was 7.4 × 10(5), 2.2 × 10(6) and 1.6 × 10(5) tons, respectively. The nutrient loading from the eight major rivers into the coastal waters peaked in summer and autumn, probably due to the large water discharge in the wet season. The Yangtze River was the largest riverine nutrient source for the coastal waters, contributing 48% of the NH3-N discharges, 66% of the TN discharges and 84% of the TP discharges of the eight major rivers in 2012. The East China Sea received the majority of the nutrient discharges, i.e. 50% of NH3-N (2.7 × 10(5) tons), 70% of TN (2.2 × 10(6) tons) and 87% of TP (2.5 × 10(5) tons) in 2012. The riverine discharge of TN into the Yellow Sea and Bohai Sea was lower than that from the direct atmospheric deposition, while for the East China Sea, the riverine TN input was larger.

Point discharge current measurements beneath dust devils

USDA-ARS?s Scientific Manuscript database

We document for the first time observations of point discharge currents under dust devils using a novel compact sensor deployed in summer 2016 at the USDA-ARS Jornada Experimental Range in New Mexico, USA. A consistent signature is noted in about a dozen events seen over 40 days, with a positive cur...

Site of maxima of conductivity, temperatures, density of the current and specific capacity of the thermal emission in the HFI-discharge

NASA Astrophysics Data System (ADS)

Gerasimov, A.; Kirpichnikov, A.; Sabirova, F.; Gainullin, R.

2017-11-01

On the basis of theoretical analysis of distributions of the conductivity, current density and specific power of heat release in the high-frequency induction discharge, a law of crowding of maxima of these values has been established.

Simulated groundwater flow paths, travel time, and advective transport of nitrogen in the Kirkwood-Cohansey aquifer system, Barnegat Bay–Little Egg Harbor Watershed, New Jersey

USGS Publications Warehouse

Voronin, Lois M.; Cauller, Stephen J.

2017-07-31

Elevated concentrations of nitrogen in groundwater that discharges to surface-water bodies can degrade surface-water quality and habitats in the New Jersey Coastal Plain. An analysis of groundwater flow in the Kirkwood-Cohansey aquifer system and deeper confined aquifers that underlie the Barnegat Bay–Little Egg Harbor (BB-LEH) watershed and estuary was conducted by using groundwater-flow simulation, in conjunction with a particle-tracking routine, to provide estimates of groundwater flow paths and travel times to streams and the BB-LEH estuary.Water-quality data from the Ambient Groundwater Quality Monitoring Network, a long-term monitoring network of wells distributed throughout New Jersey, were used to estimate the initial nitrogen concentration in recharge for five different land-use classes—agricultural cropland or pasture, agricultural orchard or vineyard, urban non-residential, urban residential, and undeveloped. Land use at the point of recharge within the watershed was determined using a geographic information system (GIS). Flow path starting locations were plotted on land-use maps for 1930, 1973, 1986, 1997, and 2002. Information on the land use at the time and location of recharge, time of travel to the discharge location, and the point of discharge were determined for each simulated flow path. Particle-tracking analysis provided the link from the point of recharge, along the particle flow path, to the point of discharge, and the particle travel time. The travel time of each simulated particle established the recharge year. Land use during the year of recharge was used to define the nitrogen concentration associated with each flow path. The recharge-weighted average nitrogen concentration for all flow paths that discharge to the Toms River upstream from streamflow-gaging station 01408500 or to the BB-LEH estuary was calculated.Groundwater input into the Barnegat Bay–Little Egg Harbor estuary from two main sources— indirect discharge from base flow to streams that eventually flow into the bay and groundwater discharge directly into the estuary and adjoining coastal wetlands— is summarized by quantity, travel time, and estimated nitrogen concentration. Simulated average groundwater discharge to streams in the watershed that flow into the BB-LEH estuary is approximately 400 million gallons per day. Particle-tracking results indicate that the travel time of 56 percent of this discharge is less than 7 years. Fourteen percent of the groundwater discharge to the streams in the BB-LEH watershed has a travel time of less than 7 years and originates in urban land. Analysis of flow-path simulations indicate that approximately 13 percent of the total groundwater flow through the study area discharges directly to the estuary and adjoining coastal wetlands (approximately 64 million gallons per day). The travel time of 19 percent of this discharge is less than 7 years. Ten percent of this discharge (1 percent of the total groundwater flow through the study area) originates in urban areas and has a travel time of less than 7 years. Groundwater that discharges to the streams that flow into the BB-LEH, in general, has shorter travel times, and a higher percentage of it originates in urban areas than does direct groundwater discharge to the Barnegat Bay–Little Egg Harbor estuary.The simulated average nitrogen concentration in groundwater that discharges to the Toms River, upstream from streamflow-gaging station 01408500 was computed and compared to summary concentrations determined from analysis of multiple surface-water samples. The nitrogen concentration in groundwater that discharges directly to the estuary and adjoining coastal wetlands is a current data gap. The particle tracking methodology used in this study provides an estimate of this concentration."

Ground-Water Occurrence and Contribution to Streamflow, Northeast Maui, Hawaii

USGS Publications Warehouse

Gingerich, Stephen B.

1999-01-01

The study area lies on the northern flank of the East Maui Volcano (Haleakala) and covers about 129 square miles between the drainage basins of Maliko Gulch to the west and Makapipi Stream to the east. About 989 million gallons per day of rainfall and 176 million gallons per day of fog drip reaches the study area and about 529 million gallons per day enters the ground-water system as recharge. Average annual ground-water withdrawal from wells totals only about 3 million gallons per day; proposed (as of 1998) additional withdrawals total about 18 million gallons per day. Additionally, tunnels and ditches of an extensive irrigation network directly intercept at least 10 million gallons per day of ground water. The total amount of average annual streamflow in gaged stream subbasins upstream of 1,300 feet altitude is about 255 million gallons per day and the total amount of average annual base flow is about 62 million gallons per day. Six major surface-water diversion systems in the study area have diverted an average of 163 million gallons per day of streamflow (including nearly all base flow of diverted streams) for irrigation and domestic supply in central Maui during 1925-97. Fresh ground water is found in two main forms. West of Keanae Valley, ground-water flow appears to be dominated by a variably saturated system. A saturated zone in the uppermost rock unit, the Kula Volcanics, is separated from a freshwater lens near sea level by an unsaturated zone in the underlying Honomanu Basalt. East of Keanae Valley, the ground-water system appears to be fully saturated above sea level to altitudes greater than 2,000 feet. The total average annual streamflow of gaged streams west of Keanae Valley is about 140 million gallons per day at 1,200 feet to 1,300 feet altitude. It is not possible to estimate the total average annual streamflow at the coast. All of the base flow measured in the study area west of Keanae Valley represents ground-water discharge from the high-elevation saturated zone. Total average daily ground-water discharge from the high-elevation saturated zone upstream of 1,200 feet altitude is greater than 38 million gallons per day, all of which is eventually removed from the streams by surface-water diversion systems. Perennial streamflow has been measured at altitudes greater than 3,000 feet in several of the streams. Discharge from the high-elevation saturated zone is persistent even during periods of little rainfall. The total average annual streamflow of the gaged streams east of Keanae Valley is about 109 million gallons per day at about 1,300 feet altitude. It is not possible to estimate the total average annual streamflow at the coast nor at higher altitudes. All of the base flow measured east of Keanae Valley represents ground-water discharge from the vertically extensive freshwater-lens system. Total average daily ground-water discharge to gaged streams upstream of 1,200 feet altitude is about 27 million gallons per day. About 19 million gallons per day of ground water discharges through the Kula and Hana Volcanics between about 500 feet and 1,300 feet altitude in the gaged stream sub-basins. About 13 million gallons per day of this discharge is in Hanawi Stream. The total ground-water discharge above 500 feet altitude in this part of the study area is greater than 56 million gallons per day.

Characteristics and dispersity of a two gap capillary discharge applied for long spark gap ignition in air

NASA Astrophysics Data System (ADS)

Huang, Dong; Yang, Lanjun; Guo, Haishan; Zhang, Zhiyuan; Jiang, Hongqiu; Xu, Haipeng

2017-07-01

In this paper, the characteristics and dispersity of a two gap capillary (TGC) discharge applied for long spark gap ignition are studied. Under the same discharge condition, 30 repetitive discharges are done to get a certain number of data samples. Accordingly, the change trend of the characteristics and the dispersity with the charging voltage of C1 are analyzed statistically. The delay of soft capillary discharge is determined by the saturation rate of the magnetic core of the pulse transformer and decreases with the increase in the charging voltage. The main discharge delay decreases from 1.0 kV to 2.0 kV and stops the decreasing trend when the charging voltage increases to 2.5 kV. In contrast, the current amplitude of soft capillary discharge and main discharge increases with charging voltage. Long tail extinction is witnessed at the charging voltage of 1.0 kV and the major cause is the insufficient pressure in the post discharge. The waveform of the capillary arc resistivity is U-like shape and the minimum resistivity decreases with the increase in the charging voltage. Meanwhile, the arc resistivity in the ascending stage is much higher than that in the descending stage with the same value of the discharge current. The energy consumption of the TGC discharge can be mainly divided into four parts and more than 70% of the energy is consumed in main discharge.

Pulsed electromagnetic gas accelleration. [incorporation of hollow cathode in plasma discharge and suitability determination of MPD discharge as plasmadynamic laser source

NASA Technical Reports Server (NTRS)

Jahn, R. G.

1973-01-01

Direct measurement with thermocouples of the power deposited in the anode of a multi-megawatt magnetoplasmadynamic discharge has shown the fractional anode power to decrease from 50% at 200 kW to 10% at 20 MW. Using local measurements of current density, electric potential, and electron temperature, the traditional model for heat conduction to the anode is found to be inadequate. Other experiments in which the voltage-current characteristics and exhaust velocities of MPD arcs using Plexiglas and boron nitride chamber insulators and various mass injection configurations show that ablation can affect nominal accelerator operation in several distinct ways. The incorporation of a hollow cathode in a 7 kA plasma discharge has shown that a stable current attachment can be realized in the cavity without the aid of cathode heaters, keeper electrodes, or emissive coatings.

Intelligent automotive battery systems

NASA Astrophysics Data System (ADS)

Witehira, P.

A single power-supply battery is incompatible with modern vehicles. A one-cmbination 12 cell/12 V battery, developed by Power Beat International Limited (PBIL), is described. The battery is designed to be a 'drop in' replacement for existing batteries. The cell structures, however, are designed according to load function, i.e., high-current shallow-discharge cycles and low-current deep-discharge cycles. The preferred energy discharge management logic and integration into the power distribution network of the vehicle to provide safe user-friendly usage is described. The system is designed to operate transparent to the vehicle user. The integrity of the volatile high-current cells is maintained by temperature-sensitive voltage control and discharge management. The deep-cycle cells can be fully utilized without affecting startability under extreme conditions. Electric energy management synchronization with engine starting will provide at least 6% overall reduction in hydrocarbon emissions using an intelligent on-board power-supply technology developed by PBIL.

Power matching between plasma generation and electrostatic acceleration in helicon electrostatic thruster

NASA Astrophysics Data System (ADS)

Ichihara, D.; Nakagawa, Y.; Uchigashima, A.; Iwakawa, A.; Sasoh, A.; Yamazaki, T.

2017-10-01

The effects of a radio-frequency (RF) power on the ion generation and electrostatic acceleration in a helicon electrostatic thruster were investigated with a constant discharge voltage of 300 V using argon as the working gas at a flow rate either of 0.5 Aeq (Ampere equivalent) or 1.0 Aeq. A RF power that was even smaller than a direct-current (DC) discharge power enhanced the ionization of the working gas, thereby both the ion beam current and energy were increased. However, an excessively high RF power input resulted in their saturation, leading to an unfavorable increase in an ionization cost with doubly charged ion production being accompanied. From the tradeoff between the ion production by the RF power and the electrostatic acceleration made by the direct current discharge power, the thrust efficiency has a maximum value at an optimal RF to DC discharge power ratio of 0.6 - 1.0.

Quantitative characterization of arc discharge as vacuum interface

DOE PAGES

Huang, S.; Zhu, K.; Lu, Y. R.; ...

2014-12-19

An arc discharge with channel diameters of 3 mm and 6 mm and lengths between 30mm and 60mm was experimentally investigated for its potential to function as plasma window, i.e., interface vacuum regions of different pressures. In this study, electron temperature of the plasma channel measured spectroscopically varied in the range of 7000K to 15000K, increasing with discharge current while decreasing with gas flow rate. The plasma window had a slightly positive I-V characteristics over the whole range of investigated current 30A–70 A. Measurements of pressure separation capability, which were determined by input current, gas flow rate, discharge channel diameter,more » and length, were well explained by viscosity effect and “thermal-block” effect. The experimental results of global parameters including temperature, gas flow rate, and voltage had a good agreement with the simulation results calculated by an axis-symmetry Fluent-based magneto-hydrodynamic model.« less

Sulfate threshold target to control methylmercury levels in wetland ecosystems

USGS Publications Warehouse

Corrales, J.; Naja, G.M.; Dziuba, C.; Rivero, R.G.; Orem, W.

2011-01-01

Sulfate contamination has a significant environmental implication through the stimulation of toxic hydrogen sulfide and methylmercury (MeHg) production. High levels of MeHg are a serious problem in many wetland ecosystems worldwide. In the Florida Everglades, it has been demonstrated that increasing MeHg occurrence is due to a sulfate contamination problem. A promising strategy of lowering the MeHg occurrence is to reduce the amount of sulfate entering the ecosystem. High surface water sulfate concentrations in the Everglades are mainly due to discharges from the Everglades Agricultural Area (EAA) canals. Water and total sulfur mass balances indicated that total sulfur released by soil oxidation, Lake Okeechobee and agricultural application were the major sources contributing 49,169, 35,217 and 11,775mtonsyear-1, respectively. Total sulfur loads from groundwater, levees, and atmospheric deposition contributed to a lesser extent: 4055; 5858 and 4229mtonsyear-1, respectively. Total sulfur leaving the EAA into Water Conservation Areas (WCAs) through canal discharge was estimated at 116,360mtonsyear-1, and total sulfur removed by sugarcane harvest accounted for 23,182mtonsyear-1. Furthermore, a rise in the mineral content and pH of the EAA soil over time, suggested that the current rates of sulfur application would increase as the buffer capacity of the soil increases. Therefore, a site specific numeric criterion for sulfate of 1mgL-1 was recommended for the protection of the Everglades; above this level, mercury methylation is enhanced. In parallel, sulfide concentrations in the EAA exceeded the 2??gL-1 criterion for surface water already established by the U.S. Environmental Protection Agency (EPA). ?? 2011 Elsevier B.V.

Methods for Estimating Annual Wastewater Nutrient Loads in the Southeastern United States

USGS Publications Warehouse

McMahon, Gerard; Tervelt, Larinda; Donehoo, William

2007-01-01

This report describes an approach for estimating annual total nitrogen and total phosphorus loads from point-source dischargers in the southeastern United States. Nutrient load estimates for 2002 were used in the calibration and application of a regional nutrient model, referred to as the SPARROW (SPAtially Referenced Regression On Watershed attributes) watershed model. Loads from dischargers permitted under the National Pollutant Discharge Elimination System were calculated using data from the U.S. Environmental Protection Agency Permit Compliance System database and individual state databases. Site information from both state and U.S. Environmental Protection Agency databases, including latitude and longitude and monitored effluent data, was compiled into a project database. For sites with a complete effluent-monitoring record, effluent-flow and nutrient-concentration data were used to develop estimates of annual point-source nitrogen and phosphorus loads. When flow data were available but nutrient-concentration data were missing or incomplete, typical pollutant-concentration values of total nitrogen and total phosphorus were used to estimate load. In developing typical pollutant-concentration values, the major factors assumed to influence wastewater nutrient-concentration variability were the size of the discharger (the amount of flow), the season during which discharge occurred, and the Standard Industrial Classification code of the discharger. One insight gained from this study is that in order to gain access to flow, concentration, and location data, close communication and collaboration are required with the agencies that collect and manage the data. In addition, the accuracy and usefulness of the load estimates depend on the willingness of the states and the U.S. Environmental Protection Agency to provide guidance and review for at least a subset of the load estimates that may be problematic.

Enhanced reproducibility of L-mode plasma discharges via physics-model-based q-profile feedback control in DIII-D

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

Schuster, Eugenio J.; Wehner, William P.; Barton, Joseph E.

Recent experiments on DIII-D demonstrate the potential of physics-model-based q-profile control to improve reproducibility of plasma discharges. A combined feed forward + feedback control scheme is employed to optimize the current ramp-up phase by consistently achieving target q profiles (Target 1: q min = 1.3,q 95 = 4:4; Target 2: q min = 1.65,q 95 = 5.0; Target 3: q min = 2.1,q 95 = 6:2) at prescribed times during the plasma formation phase (Target 1: t = 1.5 s; Target 2: t = 1:3 s; Target 3: t = 1.0 s). At the core of the control scheme ismore » a nonlinear, first-principles-driven, physics-based, control-oriented model of the plasma dynamics valid for low confinement (L-mode) scenarios. To prevent undesired L-H transitions, a constraint on the maximum allowable total auxiliary power is imposed in addition to the maximum powers for the individual heating and current-drive sources. Experimental results are presented to demonstrate the effectiveness of the combined feed forward + feedback control scheme to consistently achieve the desired target profiles at the predefined times. Here, these results also show how the addition of feedback control significantly improves upon the feed forward only control solution by reducing the matching error and also how the feedback controller is able to reduce the matching error as the constraint on the maximum allowable total auxiliary power is relaxed while keeping the plasma in L-mode.« less

Experimental verification of the vaporization's contribution to the shock waves generated by underwater electrical wire explosion under micro-second timescale pulsed discharge

NASA Astrophysics Data System (ADS)

Han, Ruoyu; Zhou, Haibin; Wu, Jiawei; Clayson, Thomas; Ren, Hang; Wu, Jian; Zhang, Yongmin; Qiu, Aici

2017-06-01

This paper studies pressure waves generated by exploding a copper wire in a water medium, demonstrating the significant contribution of the vaporization process to the formation of shock waves. A test platform including a pulsed current source, wire load, chamber, and diagnostic system was developed to study the shock wave and optical emission characteristics during the explosion process. In the experiment, a total of 500 J was discharged through a copper wire load 0.2 mm in diameter and 4 cm in length. A water gap was installed adjacent to the load so that the current was diverted away from the load after breakdown occurred across the water gap. This allows the electrical energy injection into the load to be interrupted at different times and at different stages of the wire explosion process. Experimental results indicate that when the load was bypassed before the beginning of the vaporization phase, the measured peak pressure was less than 2.5 MPa. By contrast, the peak pressure increased significantly to over 6.5 MPa when the water gap broke down after the beginning of the vaporization phase. It was also found that when bypassing the load after the voltage peak, similar shock waves were produced to those from a non-bypassed load. However, the total optical emission of these bypassed loads was at least an order of magnitude smaller. These results clearly demonstrate that the vaporization process is vital to the formation of shock waves and the energy deposited after the voltage collapse may only have a limited effect.

Enhanced reproducibility of L-mode plasma discharges via physics-model-based q-profile feedback control in DIII-D

DOE PAGES

Schuster, Eugenio J.; Wehner, William P.; Barton, Joseph E.; ...

2017-08-09

Recent experiments on DIII-D demonstrate the potential of physics-model-based q-profile control to improve reproducibility of plasma discharges. A combined feed forward + feedback control scheme is employed to optimize the current ramp-up phase by consistently achieving target q profiles (Target 1: q min = 1.3,q 95 = 4:4; Target 2: q min = 1.65,q 95 = 5.0; Target 3: q min = 2.1,q 95 = 6:2) at prescribed times during the plasma formation phase (Target 1: t = 1.5 s; Target 2: t = 1:3 s; Target 3: t = 1.0 s). At the core of the control scheme ismore » a nonlinear, first-principles-driven, physics-based, control-oriented model of the plasma dynamics valid for low confinement (L-mode) scenarios. To prevent undesired L-H transitions, a constraint on the maximum allowable total auxiliary power is imposed in addition to the maximum powers for the individual heating and current-drive sources. Experimental results are presented to demonstrate the effectiveness of the combined feed forward + feedback control scheme to consistently achieve the desired target profiles at the predefined times. Here, these results also show how the addition of feedback control significantly improves upon the feed forward only control solution by reducing the matching error and also how the feedback controller is able to reduce the matching error as the constraint on the maximum allowable total auxiliary power is relaxed while keeping the plasma in L-mode.« less

Discharges with surgical procedures performed less often than once per month per hospital account for two-thirds of hospital costs of inpatient surgery.

PubMed

O'Neill, Liam; Dexter, Franklin; Park, Sae-Hwan; Epstein, Richard H

2017-09-01

Most surgical discharges (54%) at the average hospital are for procedures performed no more often than once per month at that hospital. We hypothesized that such uncommon procedures would be associated with an even greater percentage of the total cost of performing all surgical procedures at that hospital. Observational study. State of Texas hospital discharge abstract data: 4th quarter of 2015 and 1st quarter of 2016. Inpatients discharged with a major therapeutic ("operative") procedure. For each of N=343 hospitals, counts of discharges, sums of lengths of stay (LOS), sums of diagnosis related group (DRG) case-mix weights, and sums of charges were obtained for each procedure or combination of procedures, classified by International Classification of Diseases version 10 Procedure Coding System (ICD-10-PCS). Each discharge was classified into 2 categories, uncommon versus not, defined as a procedure performed at most once per month versus those performed more often than once per month. Major procedures performed at most once per month per hospital accounted for an average among hospitals of 68% of the total inpatient costs associated with all major therapeutic procedures. On average, the percentage of total costs associated with uncommon procedures was 26% greater than expected based on their share of total discharges (P<0.00001). Average percentage differences were insensitive to the endpoint, with similar results for the percentage of patient days and percentage of DRG case-mix weights. Approximately 2/3rd (mean 68%) of inpatient costs among surgical patients can be attributed to procedures performed at most once per month per hospital. The finding that such uncommon procedures account for a large percentage of costs is important because methods of cost accounting by procedure are generally unsuitable for them. Copyright © 2017 Elsevier Inc. All rights reserved.

Experimental demonstration of plasma startup by coaxial helicity injection

NASA Astrophysics Data System (ADS)

Raman, R.; Jarboe, T. R.; Nelson, B. A.; Hamp, W. T.; Izzo, V. A.; O'Neill, R. G.; Redd, A. J.; Sieck, P. E.; Smith, R. J.

2004-05-01

Experimental results on the transfer of a coaxial-helicity-injection (CHI) produced discharge to inductive operation are reported. CHI assisted plasma startup is more robust than inductive only operation and reduces volt-seconds consumption. After handoff to inductive operation, the initial 100 kA of CHI produced current drops to 50 kA, then ramps up to 180 kA, using only 30 mVs, about 40% higher than that produced by induction alone. Results show that initiation of CHI discharges at lower densities produce higher levels of coupling current. Coupling a CHI produced discharge to induction from a precharged central solenoid has produced record currents of 290 kA using only 52 mWb of central solenoid flux. CHI discharges can also be generated while the central transformer is in the process of being precharged, during which period it induces a negative loop voltage on the CHI discharge. These significant results were obtained on the Helicity Injected Torus-II (HIT-II) [T.R. Jarboe, Fusion Technol. 15, 7 (1989)] spherical torus experiment (major/minor radius of 0.3/0.2 m and elongation of 1.5).

Electron distribution functions in electric field environments

NASA Technical Reports Server (NTRS)

Rudolph, Terence H.

1991-01-01

The amount of current carried by an electric discharge in its early stages of growth is strongly dependent on its geometrical shape. Discharges with a large number of branches, each funnelling current to a common stem, tend to carry more current than those with fewer branches. The fractal character of typical discharges was simulated using stochastic models based on solutions of the Laplace equation. Extension of these models requires the use of electron distribution functions to describe the behavior of electrons in the undisturbed medium ahead of the discharge. These electrons, interacting with the electric field, determine the propagation of branches in the discharge and the way in which further branching occurs. The first phase in the extension of the referenced models , the calculation of simple electron distribution functions in an air/electric field medium, is discussed. Two techniques are investigated: (1) the solution of the Boltzmann equation in homogeneous, steady state environments, and (2) the use of Monte Carlo simulations. Distribution functions calculated from both techniques are illustrated. Advantages and disadvantages of each technique are discussed.

Studies of corona and back discharges in carbon dioxide

NASA Astrophysics Data System (ADS)

Czech, Tadeusz; Sobczyk, Arkadiusz Tomasz; Jaworek, Anatol; Krupa, Andrzej; Rajch, Eryk

2013-01-01

Results of spectroscopic investigations and current-voltage characteristics of corona and back discharges generated in point-plane electrode geometry in CO2 at atmospheric pressure for positive and negative polarity of the discharge electrode are presented in the paper. Three forms of back discharge, for both polarities, were investigated: glow, streamer and low-current back-arc. To generate the back-discharges for the conditions similar to electrostatic precipitator, the plate electrode was covered with fly ash layer. In order to characterize back discharge processes, the emission spectra were measured and compared with those obtained for normal discharge, generated in the same electrode configuration but without the fly ash layer on the plate electrode. The measurements have shown that optical emission spectral lines of atoms and molecules, excited or ionised in back discharge, depend on the forms of the discharge, the discharge current, and are different in the zones close to needle electrode and fly ash layer. From the comparison of spectral lines of back and normal discharges, an effect of fly ash layer on discharge characteristics and morphology has been determined. In normal corona, the emission spectra are mainly predetermined by the working gas components, but in the case of back discharge, the atomic and molecular lines, resulting from chemical composition of fly ash, are also identified. Differences in the spectra of back discharge for positive and negative polarities of the needle electrode have been explained by considering the kind of ions generated in the crater in fly ash layer. For back arc, the emission of spectral lines of atoms and molecules from fly ash layer can be recorded in the crater zone, but in the needle zone, only the emission lines of CO2 and its decomposition products (CO and C2) can be noticed. The studies of back discharge in CO2, as one of the main components of flue gases, were undertaken because this type of discharge, after unwanted inception, decreases the energy and collection efficiencies of electrostatic precipitator. The second reason behind these studies is that CO2 is the main component of flue gas leaving oxyfuel boiler that re-circulates in the combustion-precipitation cycle. It was shown that discharges in CO2 lead to contamination of discharge electrode with carbonaceous products that can cause severe maintenance problems of electrostatic precipitator. The recognition of the characteristics of electrostatic precipitator operating in the oxyfuel system is, therefore, of crucial importance for exhaust gas cleaning in modern combustion systems.

Effect of high energy electrons on H⁻ production and destruction in a high current DC negative ion source for cyclotron.

PubMed

Onai, M; Etoh, H; Aoki, Y; Shibata, T; Mattei, S; Fujita, S; Hatayama, A; Lettry, J

2016-02-01

Recently, a filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In this study, numerical modeling of the filament arc-discharge source plasma has been done with kinetic modeling of electrons in the ion source plasmas by the multi-cusp arc-discharge code and zero dimensional rate equations for hydrogen molecules and negative ions. In this paper, main focus is placed on the effects of the arc-discharge power on the electron energy distribution function and the resultant H(-) production. The modelling results reasonably explains the dependence of the H(-) extraction current on the arc-discharge power in the experiments.

Laser-assisted guiding of electric discharges around objects

PubMed Central

Clerici, Matteo; Hu, Yi; Lassonde, Philippe; Milián, Carles; Couairon, Arnaud; Christodoulides, Demetrios N.; Chen, Zhigang; Razzari, Luca; Vidal, François; Légaré, François; Faccio, Daniele; Morandotti, Roberto

2015-01-01

Electric breakdown in air occurs for electric fields exceeding 34 kV/cm and results in a large current surge that propagates along unpredictable trajectories. Guiding such currents across specific paths in a controllable manner could allow protection against lightning strikes and high-voltage capacitor discharges. Such capabilities can be used for delivering charge to specific targets, for electronic jamming, or for applications associated with electric welding and machining. We show that judiciously shaped laser radiation can be effectively used to manipulate the discharge along a complex path and to produce electric discharges that unfold along a predefined trajectory. Remarkably, such laser-induced arcing can even circumvent an object that completely occludes the line of sight. PMID:26601188

Detrapping of tungsten nanoparticles in a direct-current argon glow discharge

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

Couëdel, L., E-mail: lenaic.couedel@univ-amu.fr; Kumar, K. Kishor; Arnas, C.

2014-12-15

Nanoparticles are grown from the sputtering of a tungsten cathode in a direct current argon glow discharge. Laser light scattering of a vertical laser sheet going through the plasma reveals that the dust particle cloud is compressed and pushed towards the anode during the discharge. Scanning electron microscopy images of substrates exposed to the plasma for given durations show that dust particles are continuously falling down on the anode during the discharge. These observations are explained by the fact that the electrostatic force at the negative glow-anode sheath boundary cannot balance the ion drag, gravity, and thermophoresis forces for particlesmore » of more than a few tens of nanometres in diameter.« less

Stage-discharge relations for Black Warrior River at Warrior Dam near Eutaw, Alabama; updated 1985

USGS Publications Warehouse

Nelson, G.H.; Ming, C.O.

1986-01-01

The construction of Warrior Dam, completed in 1962, has resulted in changes to the stage-discharge relations in the vicinity. The scarcity of current-meter measurements, coupled with backwater conditions, make definition of a single stage-discharge relation impossible without considerable error. However, as a useful alternative, limit curves were developed in 1983 that defined the limits of possible stage-discharge relations at the dam tailwater section. Since the 1983 report, 37 discharge values computed through the dam for the flood of December 1983 were used to verify or update the lower end of the limit curves. Data obtained from a current-meter measurement of the February 1961 flood (furnished by the U.S. Army Corps of Engineers) were used to update the upper end of the curves. This report presents the updated information. (USGS)

Comparison of acoustic doppler current profiler and Price AA mechanical current meter measurements made during the 2011 Mississippi River Flood

USGS Publications Warehouse

O'Brien, Patrick; Mueller, David; Pratt, Thad

2012-01-01

The Mississippi River and Tributaries project performed as designed during the historic 2011 Mississippi River flood, with many of the operational decisions based on discharge targets as opposed to stage. Measurement of discharge at the Tarbert Landing, Mississippi range provides critical information used in operational decisions for the floodways located in Louisiana. Historically, discharge measurements have been made using a Price AA current meter and the mid-section method, and a long record exists based on these types of measurements, including historical peak discharges. Discharge measurements made using an acoustic Doppler current profiler from a moving boat have been incorporated into the record since the mid 1990's, and are used along with the Price AA mid-section measurements. During the 2011 flood event, both methods were used and appeared to provide different results at times. The apparent differences between the measurement techniques are due to complex hydrodynamics at this location that created large spatial and temporal fluctuations in the flow. The data and analysis presented herein show the difference between the two methods to be within the expected accuracy of the measurements when the measurements are made concurrently. The observed fluctuations prevent valid comparisons of data collected sequentially or even with different observation durations.

Effect of secondary electron emission on subnanosecond breakdown in high-voltage pulse discharge

NASA Astrophysics Data System (ADS)

Schweigert, I. V.; Alexandrov, A. L.; Gugin, P.; Lavrukhin, M.; Bokhan, P. A.; Zakrevsky, Dm E.

2017-11-01

The subnanosecond breakdown in open discharge may be applied for producing superfast high power switches. Such fast breakdown in high-voltage pulse discharge in helium was explored both in experiment and in kinetic simulations. The kinetic model of electron avalanche development was developed using PIC-MCC technique. The model simulates motion of electrons, ions and fast helium atoms, appearing due to ions scattering. It was shown that the mechanism responsible for ultra-fast breakdown development is the electron emission from cathode. The photoemission and emission by ions or fast atoms impact is the main reason of current growth at the early stage of breakdown, but at the final stage, when the voltage on discharge gap drops, the secondary electron emission (SEE) is responsible for subnanosecond time scale of current growth. It was also found that the characteristic time of the current growth τS depends on the SEE yield of the cathode material. Three types of cathode material (titanium, SiC, and CuAlMg-alloy) were tested. It is shown that in discharge with SiC and CuAlMg-alloy cathodes (which have enhanced SEE) the current can increase with a subnanosecond characteristic time as small as τS = 0.4 ns, for the pulse voltage amplitude of 5- 12 kV..

Relation Between Sprite Distribution and Source Locations of VHF Pulses Derived From JEM- GLIMS Measurements

NASA Astrophysics Data System (ADS)

Sato, Mitsuteru; Mihara, Masahiro; Ushio, Tomoo; Morimoto, Takeshi; Kikuchi, Hiroshi; Adachi, Toru; Suzuki, Makoto; Yamazaki, Atsushi; Takahashi, Yukihiro

2015-04-01

JEM-GLIMS is continuing the comprehensive nadir observations of lightning and TLEs using optical instruments and electromagnetic wave receivers since November 2012. For the period between November 20, 2012 and November 30, 2014, JEM-GLIMS succeeded in detecting 5,048 lightning events. A total of 567 events in 5,048 lightning events were TLEs, which were mostly elves events. To identify the sprite occurrences from the transient optical flash data, it is necessary to perform the following data analysis: (1) a subtraction of the appropriately scaled wideband camera data from the narrowband camera data; (2) a calculation of intensity ratio between different spectrophotometer channels; and (3) an estimation of the polarization and CMC for the parent CG discharges using ground-based ELF measurement data. From a synthetic comparison of these results, it is confirmed that JEM-GLISM succeeded in detecting sprite events. The VHF receiver (VITF) onboard JEM-GLIMS uses two patch-type antennas separated by a 1.6-m interval and can detect VHF pulses emitted by lightning discharges in the 70-100 MHz frequency range. Using both an interferometric technique and a group delay technique, we can estimate the source locations of VHF pulses excited by lightning discharges. In the event detected at 06:41:15.68565 UT on June 12, 2014 over central North America, sprite was distributed with a horizontal displacement of 20 km from the peak location of the parent lightning emission. In this event, a total of 180 VHF pulses were simultaneously detected by VITF. From the detailed data analysis of these VHF pulse data, it is found that the majority of the source locations were placed near the area of the dim lightning emission, which may imply that the VHF pulses were associated with the in-cloud lightning current. At the presentation, we will show detailed comparison between the spatiotemporal characteristics of sprite emission and source locations of VHF pulses excited by the parent lightning discharges of sprites.

Positron Annihilation in Thunderstorms Observed by ILDAS.

NASA Astrophysics Data System (ADS)

Kochkin, P.; Sarria, D., Sr.; Van Deursen, A.; de Boer, A.; Bardet, M.; Allasia, C.; Flourens, F.; Østgaard, N.

2017-12-01

Positron clouds within thunderstorms were for the first time reported in 2015 [Dwyer et al. 2015]. The observation was made by the Airborne Detector for Energetic Lightning Emissions (ADELE) in 2009 at 14.1 km altitude. Strong 511 keV line enhancement was recorded synchronously with nearby electrical activity. It lasted at least 0.2 s and was modeled as annihilation from disperse positron cloud more than a kilometer across. Different positron generation mechanisms were proposed in the paper. In January 2016 an Airbus A340 factory test aircraft was intentionally flying through thunderstorms over Northern Australia. The aircraft was equipped with a dedicated in-flight lightning detection system ILDAS (http://ildas.nlr.nl). The system contains two gamma-ray scintillation detectors each with 38x38 mm cylinder LaBr3 crystals. Total 9 video cameras were installed on-board to monitor the outer surfaces. When the aircraft flew at 12 km inside an active thundercloud, the ambient electric field was strong enough to trigger electrical discharges from the sharp edges. One sequence of such discharges was accompanied with enhancements of 511 keV line, each lasted for 0.5 - 1.0 s and total duration over 15 s. The video cameras recorded electrical discharges attached to the aircraft during this process. ILDAS reported brief 100 A current pulses in association with these discharges. Ground-based lightning location networks, i.e. WWLLN and local Australian LIAS, have not detected any sferics from this region. A detailed Geant4 model of the aircraft was created. The model was used to test different production mechanisms for the observed emission. In this presentation we will show a detailed reconstruction ofthe events with precise mapping on infrared cloud snapshot. Videos from the cameras at the positron detection moment will be shown. The results of the Geant4 simulation will be presented and discussed. References: 1. Dwyer, Joseph R., et al. "Positron clouds within thunderstorms." Journal of Plasma Physics 81.4 (2015).

Effect of turbulent flow on an atmospheric-pressure AC powered gliding arc discharge

NASA Astrophysics Data System (ADS)

Kong, Chengdong; Gao, Jinlong; Zhu, Jiajian; Ehn, Andreas; Aldén, Marcus; Li, Zhongshan

2018-06-01

A high-power gliding arc (GA) discharge was generated in a turbulent air flow driven by a 35 kHz alternating current electric power supply. The effects of the flow rate on the characteristics of the GA discharge were investigated using combined optical and electrical diagnostics. Phenomenologically, the GA discharge exhibits two types of discharge, i.e., glow type and spark type, depending on the flow rates and input powers. The glow-type discharge, which has peak currents of hundreds of milliamperes, is sustained at low flow rates. The spark-type discharge, which is characterized by a sharp current spike of several amperes with duration of less than 1 μs, occurs more frequently as the flow rate increases. Higher input power can suppress spark-type discharges in moderate turbulence, but this effect becomes weak under high turbulent conditions. Physically, the transition between glow- and spark-type is initiated by the short cutting events and the local re-ignition events. Short cutting events occur owing to the twisting, wrinkling, and stretching of the plasma columns that are governed by the relatively large vortexes in the flow. Local re-ignition events, which are defined as re-ignition along plasma columns, are detected in strong turbulence due to increment of the impedance of the plasma column and consequently the internal electric field strength. It is suggested that the vortexes with length scales smaller than the size of the plasma can penetrate into the plasma column and promote mixing with surroundings to accelerate the energy dissipation. Therefore, the turbulent flow influences the GA discharges by ruling the short cutting events with relatively large vortexes and the local re-ignition events with small vortexes.

Numerical simulation and analysis of electromagnetic-wave absorption of a plasma slab created by a direct-current discharge with gridded anode

NASA Astrophysics Data System (ADS)

Yuan, Chengxun; Tian, Ruihuan; Eliseev, S. I.; Bekasov, V. S.; Bogdanov, E. A.; Kudryavtsev, A. A.; Zhou, Zhongxiang

2018-03-01

In this paper, we present investigation of a direct-current discharge with a gridded anode from the point of view of using it as a means of creating plasma coating that could efficiently absorb incident electromagnetic (EM) waves. A single discharge cell consists of two parallel plates, one of which (anode) is gridded. Electrons emitted from the cathode surface are accelerated in the short interelectrode gap and are injected into the post-anode space, where they lose acquired energy on ionization and create plasma. Numerical simulations were used to investigate the discharge structure and obtain spatial distributions of plasma density in the post-anode space. The numerical model of the discharge was based on a simple hybrid approach which takes into account non-local ionization by fast electrons streaming from the cathode sheath. Specially formulated transparency boundary conditions allowed performing simulations in 1D. Simulations were carried out in air at pressures of 10 Torr and higher. Analysis of the discharge structure and discharge formation is presented. It is shown that using cathode materials with lower secondary emission coefficients can allow increasing the thickness of plasma slabs for the same discharge current, which can potentially enhance EM wave absorption. Spatial distributions of electron density obtained during simulations were used to calculate attenuation of an incident EM wave propagating perpendicularly to the plasma slab boundary. It is shown that plasma created by means of a DC discharge with a gridded anode can efficiently absorb EM waves in the low frequency range (6-40 GHz). Increasing gas pressure results in a broader range of wave frequencies (up to 500 GHz) where a considerable attenuation is observed.

Measurements of velocity and discharge, Grand Canyon, Arizona, May 1994

USGS Publications Warehouse

Oberg, Kevin A.; Fisk, Gregory G.; ,

1995-01-01

The U.S. Geological Survey (USGS) evaluated the feasibility of utilizing an acoustic Doppler current profiler (ADCP) to collect velocity and discharge data in the Colorado River in Grand Canyon, Arizona, in May 1994. An ADCP is an instrument that can be used to measure water velocity and discharge from a moving boat. Measurements of velocity and discharge were made with an ADCP at 54 cross sections along the Colorado River between the Little Colorado River and Diamond Creek. Concurrent measurements of discharge with an ADCP and a Price-AA current meter were made at three U.S. Geological Survey streamflow-gaging stations: Colorado River above the Little Colorado River near Desert View, Colorado River near Grand Canyon, and Colorado River above Diamond Creek near Peach Springs. Discharges measured with an ADCP were within 3 percent of the rated discharge at each streamflow-gaging station. Discharges measured with the ADCP were within 4 percent of discharges measured with a Price-AA meter, except at the Colorado River above Diamond Creek. Vertical velocity profiles were measured with the ADCP from a stationary position at four cross sections along the Colorado River. Graphs of selected vertical velocity profiles collected in a cross section near National Canyon show considerable temporal variation among profile.

A Modelling Study of the Coastal Current in the Northwestern South China Sea: Response to Strong and Weak Southwest Monsoon

NASA Astrophysics Data System (ADS)

Ding, Y.; Yu, J.; Bao, X.; Yao, Z.

2016-02-01

The characteristics and dynamical mechanism of summer-time coastal current over the northwestern South China Sea (NSCS) shelf have been investigated based on a high resolution unstructured-grid finite volume community ocean model (FVCOM). Model-data comparison demonstrates that model well resolves the coastal dynamics over the NSCS shelf. The coastal current on the NSCS shelf is intensively influenced by monsoon and freshwater discharge of the Pearl River. Strong southwesterly wind drive the coastal current northeastward. However, under weak southwest monsoon, the coastal current west of Pearl River estuary (PRE) advects toward southwest, and splits into two parts when reaching east of the Qiongzhou Strait, with one branch entering the Gulf of Tonkin through the Qiongzhou Strait, transporting low salinity water into the Gulf of Tonkin, and the other part flows cyclonic and interacts with the northeastward current around southeast of Hainan Island, forming a cyclonic eddy east of the Qiongzhou Strait. A variety of model experiments focused on freshwater discharge, wind forcing, tidal rectification, and stratification are performed to study the physical mechanism of the southwestward coastal current which is usually against the summer wind. Process-oriented experiment results indicate that the southwest monsoon and freshwater discharge are important factors influencing the formation of southwestward coastal current during summer. Momentum balance analysis suggests that the along shelf barotropic pressure gradient due to the Pearl River discharge and wind forcing provides the main driving force for the southwestward coastal current.

Electric fields and current densities under small Florida thunderstorms

NASA Technical Reports Server (NTRS)

Deaver, Lance E.; Krider, E. P.

1991-01-01

Results are presented of measurements of the electric field E and Maxwell current density that were performed simultaneously under and near small Florida thunderstorms. It is shown that the amplitude of JM is of the order of 1 nA/sq cm or less in the absence of precipitation and that there are regular time variations in JM during the intervals between lightning discharges that tend to have the same shapes after different discharges in different storms. It is argued that the major causes of time variations in JM between lightning discharges are currents that flow in the finitely conducting atmosphere in response to the field changes rather than rapid time variations in the strength of cloud current sources. The displacement current densities that are computed from the E records dominate JM except when there is precipitation, when E is large and steady, or when E is unusually noisy.

New model simulations of the global atmospheric electric circuit driven by thunderstorms and electrified shower clouds: The roles of lightning and sprites

NASA Astrophysics Data System (ADS)

Rycroft, Michael J.; Odzimek, Anna; Arnold, Neil F.; Füllekrug, Martin; Kułak, Andrzej; Neubert, Torsten

2007-12-01

Several processes acting below, in and above thunderstorms and in electrified shower clouds drive upward currents which close through the global atmospheric electric circuit. These are all simulated in a novel way using the software package PSpice. A moderate negative cloud-to-ground lightning discharge from the base of a thunderstorm increases the ionospheric potential above the thundercloud by 0.0013%. Assuming the ionosphere to be an equipotential surface, this discharge increases the current flowing in the global circuit and the fair-weather electric field also by 0.0013%. A moderate positive cloud-to-ground lightning discharge from the bottom of a thunderstorm decreases the ionospheric potential by 0.014%. Such a discharge may trigger a sprite, causing the ionospheric potential to decrease by ˜1V. The time scales for the recovery of the ionospheric potential are shown to be ˜250s, which is of the same order as the CR time constant for the global circuit. Knowing the global average rate of lightning discharges, it is found that negative cloud-to-ground discharges increase the ionospheric potential by only ˜4%, and that positive cloud-to-ground discharges reduce it by ˜3%. Thus, overall, lightning contributes only ˜1%—an almost insignificant proportion—to maintaining the high potential of the ionosphere. It is concluded that the net upward current to the ionosphere due to lightning is only ˜20A. Further, it is concluded that conduction and convection currents associated with “batteries” within thunderclouds and electrified shower clouds contribute essentially equally (˜500A each) to maintaining the ionospheric potential.

Overview of recent experimental results from the Aditya tokamak

NASA Astrophysics Data System (ADS)

Tanna, R. L.; Ghosh, J.; Chattopadhyay, P. K.; Raj, Harshita; Patel, Sharvil; Dhyani, P.; Gupta, C. N.; Jadeja, K. A.; Patel, K. M.; Bhatt, S. B.; Panchal, V. K.; Patel, N. C.; Chavda, Chhaya; Praveenlal, E. V.; Shah, K. S.; Makawana, M. N.; Jha, S. K.; Gopalkrishana, M. V.; Tahiliani, K.; Sangwan, Deepak; Raju, D.; Nagora, Umesh; Pathak, S. K.; Atrey, P. K.; Purohit, S.; Raval, J.; Joisa, Y. S.; Rao, C. V. S.; Chowdhuri, M. B.; Banerjee, S.; Ramaiya, N.; Manchanda, R.; Thomas, J.; Kumar, Ajai; Ajay, Kumar; Sharma, P. K.; Kulkarni, S. V.; Sathyanarayana, K.; Shukla, B. K.; Das, Amita; Jha, R.; Saxena, Y. C.; Sen, A.; Kaw, P. K.; Bora, D.; the ADITYA Team

2017-10-01

Several experiments, related to controlled thermonuclear fusion research and highly relevant for large size tokamaks, including ITER, have been carried out in ADITYA, an ohmically heated circular limiter tokamak. Repeatable plasma discharges of a maximum plasma current of ~160 kA and discharge duration beyond ~250 ms with a plasma current flattop duration of ~140 ms have been obtained for the first time in ADITYA. The reproducibility of the discharge reproducibility has been improved considerably with lithium wall conditioning, and improved plasma discharges are obtained by precisely controlling the position of the plasma. In these discharges, chord-averaged electron density ~3.0-4.0  ×  1019 m-3 using multiple hydrogen gas puffs, with a temperature of the order of ~500-700 eV, have been achieved. Novel experiments related to disruption control are carried out and disruptions, induced by hydrogen gas puffing, are successfully mitigated using the biased electrode and ion cyclotron resonance pulse techniques. Runaway electrons are successfully mitigated by applying a short local vertical field (LVF) pulse. A thorough disruption database has been generated by identifying the different categories of disruption. Detailed analysis of several hundred disrupted discharges showed that the current quench time is inversely proportional to the q edge. Apart from this, for volt-sec recovery during the plasma formation phase, low loop voltage start-up and current ramp-up experiments have been carried out using electron cyclotron resonance heating (ECRH). Successful recovery of volt-sec leads to the achievement of longer plasma discharge durations. In addition, the neon gas puff assisted radiative improved confinement mode has also been achieved in ADITYA. All of the above mentioned experiments will be discussed in this paper.

Colored Dissolved Organic Matter Dynamics in the Northern Gulf of Mexico from Ocean Color and Numerical Model Results

DTIC Science & Technology

2014-07-01

Various factors such as winds , river discharges, and detached eddies from the Loop Current can contribute to the generation of currents over the...component of transport over the inner shelf is produced by wind (40–48%), with river discharge (28–33%) and Loop Current (LC) eddies (19–33...accounting for the rest (Oey, 1995). Two seasonal current patterns that depend on wind characteristics are distinguishable over the shelf (Cho, Reid, and

Pediatric Tracheotomy: A 5-Year Experience in Düzce University Medical Faculty

PubMed Central

Ünlü, İlhan; İlhan, Ethem; Ünlü, Elif Nisa; Ateş, Hakan; Gün, Emrah; Yaman, Hüseyin; Güçlü, Ender

2015-01-01

Objective Tracheotomy is one of the oldest surgical procedures. Pediatric tracheotomy indications have changed in recent decades. Currently, tracheotomy is performed because of prolonged intubation, upper airway obstruction, neuromuscular, and craniofacial anomalies instead of acute airway infections. This study aims to present our experience regarding indications and complications of tracheotomy in pediatric patients. Methods We retrospectively evaluated 17 pediatric patients who underwent tracheotomy because of prolonged intubation, increased pulmonary secretions, and upper respiratory tract obstruction from June 2010 to June 2015. The patients’ age, gender, tracheotomy indications, duration of intubation, complications, and actual clinical condition were recorded. Results Tracheotomy was performed on 17 pediatric patients in our clinic. Discharged patients were followed with a 3-month routine check. Six patients (35.29%) had died because of a primary disease during follow-up, and one (5.88%) of them was a one-day-old newborn who had anomalies that were incompatible with life. In one patient, emergency tracheotomy was performed because of a tracheal trauma. None of the patients has been decannulated except one (5.88%). One (5.88%) patient had an accidental decannulation, while another had bleeding in the operation field. The total minor complication rate was 11.76%, and no major complication was observed. Two (11.76%) of the discharged patients underwent re-operation for widening of the tracheotomy stoma during their routine visit. Conclusion Currently, tracheotomy in pediatric patients is mostly performed for prolonged intubation and upper respiratory tract obstruction for which intubation is not possible. Tracheotomy enables the discharge of these patients after training their families. PMID:29391991

Superior short-term cholesterol control and achievement of the adult treatment panel III low-density lipoprotein goals with initiation of statin therapy by the time of hospital discharge following acute myocardial infarction.

PubMed

Bybee, Kevin A; Powell, Brian D; Williams, Brent A; Murphy, Joseph G; Kopecky, Stephen L; Wright, R Scott

2004-03-15

In a community-based population, we compared serum cholesterol concentrations following hospital discharge after acute myocardial infarction based on statin therapy at the time of hospital discharge. At the time of follow-up cholesterol measurement, patients discharged from the hospital on a statin had lower mean low-density lipoprotein (LDL) (106.4 vs 116.7 mg/dl, p <0.01) and total cholesterol (182.2 vs 193.6 mg/dl, p <0.01) concentrations, larger absolute reductions in LDL (-24.7 vs -4.7 mg/dl, p <0.01) and total cholesterol (-24.2 vs -0.1 mg/dl, p <0.01) from pre-myocardial infarction levels, and superior attainment of the Adult Treatment Panel III LDL goal of <100 mg/dl at the time of follow-up compared with patients who were discharged without a statin (49% vs 33%; adjusted odds ratio 2.56; p <0.01).

Evolution of lightning in an isolated hailstorm of moderate size in the tropics

NASA Astrophysics Data System (ADS)

Kamra, A. K.; Pawar, S. D.

2007-10-01

Evolution of lightning activity in a tropical hailstorm of moderate size that developed in the premonsoon season at Pune (18°32'N, 73°51'E, 559 m above sea level) is studied from the measurements of surface electric field, the Maxwell current and thunder. Total flash rate is counted from the electric field record, and the cloud-to-ground (CG) flash rate is estimated from the visual observations. Precise timings of their occurrence were confirmed from the observations of overshoot in the Maxwell current records. The storm exhibited an almost constant rate of one CG flash every 1 to 2 min over the whole life time of the storm. The ratio of intracloud (IC) to CG flashes (IC/CG) increased with the increase in total flash rate. In the convective stage of the storm, field changes from consecutive flashes were generally found to alternate in polarity. Moreover, in this stage, field changes occur in pairs, the first field change of each pair being of negative polarity and the second one of positive polarity. The two field changes in a pair occur with an average time difference of 14.3 ± 8.4 s while two consecutive pairs appear after 29.3 ± 9.1 s. In between the convective and mature stages, our observations suggest the occurrence of the phenomenon of rain gush and the field excursion associated with falling precipitation. Development of the mature stage was marked with rapid transitions in the surface electric field and the Maxwell current polarities from negative to positive. Further, total flash rate and IC/CG ratio sharply increase, and the lightning-induced electric field changes become almost exclusively of negative polarity. Observations suggest possibly a lifting up of the charging region in mature stage of the storm. The dissipating stage of the storm witnessed hail and rain showers, sharp transition of electric field and the Maxwell current from positive to negative polarity and occurrence of a few positive CG discharges. Our observations are consistent with the general belief that that some lightning flashes, by neutralizing and depositing charge in the region of opposite polarity, change the charge distribution so as to trigger another discharge in the storm.

Photo-triggering and secondary electron produced ionization in electric discharge ArF* excimer lasers

NASA Astrophysics Data System (ADS)

Xiong, Zhongmin; Kushner, Mark J.

2011-10-01

Electric discharge excimer lasers are sustained in multi-atmosphere attaching gas mixtures that are typically preionized to enable a reproducible, uniform glow, which maximizes optical quality and gain. This preionization is often accomplished using UV light produced by a corona discharge within the plasma cavity. To quantify the relationship between corona discharge properties and those of the laser discharge, the triggering of electron avalanche by preionizing UV light in an electric discharge-pumped ArF* excimer laser was numerically investigated using a two-dimensional model. The preionizing UV fluxes were generated by a corona-bar discharge driven by the same voltage pulse as the main discharge sustained in a multi-atmospheric Ne/Ar/Xe/F2 gas mixture. The resulting peak photo-electron density in the inter-electrode spacing is around 108 cm-3, and its distribution is biased toward the UV source. The preionization density increases with increasing dielectric constant and capacitance of the corona bar. The symmetry and uniformity of the discharge are, however, improved significantly once the main avalanche develops. In addition to bulk electron impact ionization, the ionization generated by sheath accelerated secondary electrons was found to be important in sustaining the discharge current at experimentally observed values. At peak current, the magnitude of the ionization by sheath accelerated electrons is comparable to that from bulk electron impact in the vicinity of the cathode.

Comparison of electrical and optical characteristics in gas-phase and gas-liquid phase discharges

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

Qazi, H. I. A.; Li, He-Ping, E-mail: liheping@tsinghua.edu.cn; Zhang, Xiao-Fei

This paper presents an AC-excited argon discharge generated using a gas-liquid (two-phase) hybrid plasma reactor, which mainly consists of a powered needle electrode enclosed in a conical quartz tube and grounded deionized water electrode. The discharges in the gas-phase, as well as in the two-phase, exhibit two discharge modes, i.e., the low current glow-like diffuse mode and the high current streamer-like constrict mode, with a mode transition, which exhibits a negative resistance of the discharges. The optical emission spectral analysis shows that the stronger diffusion of the water vapor into the discharge region in the two-phase discharges boosts up themore » generation of OH (A–X) radicals, and consequently, leads to a higher rotational temperature in the water-phase plasma plume than that of the gas-phase discharges. Both the increase of the power input and the decrease of the argon flow rate result in the increase of the rotational temperature in the plasma plume of the water-phase discharge. The stable two-phase discharges with a long plasma plume in the water-phase under a low power input and gas flow rate may show a promising prospect for the degradation of organic pollutants, e.g., printing and dyeing wastewater, in the field of environmental protection.« less

Optical Diagnostic Characterization of High-Power Hall Thruster Wear and Operation

NASA Technical Reports Server (NTRS)

Williams, George J., Jr.; Soulas, George C.; Kamhawi, Hani

2012-01-01

Optical emission spectroscopy is employed to correlate BN insulator erosion with high-power Hall thruster operation. Specifically, actinometry leveraging excited xenon states is used to normalize the emission spectra of ground state boron as a function of thruster operating condition. Trends in the strength of the boron signal are correlated with thruster power, discharge voltage, and discharge current. In addition, the technique is demonstrated on metallic coupons embedded in the walls of the HiVHAc EM thruster. The OES technique captured the overall trend in the erosion of the coupons which boosts credibility in the method since there are no data to which to calibrate the erosion rates of high-power Hall thrusters. The boron signals are shown to trend linearly with discharge voltage for a fixed discharge current as expected. However, the boron signals of the higher-power NASA 300M and NASA 457Mv2 trend with discharge current and show an unexpectedly weak to inverse dependence on discharge voltage. Electron temperatures measured optically in the near-field plume of the thruster agree well with Langmuir probe data. However, the optical technique used to determine Te showed unacceptable sensitivity to the emission intensities. Near-field, single-frequency imaging of the xenon neutrals is also presented as a function of operating condition for the NASA 457 Mv2.

Ozone production by a dc corona discharge in air contaminated by n-heptane

NASA Astrophysics Data System (ADS)

Pekárek, S.

2008-01-01

Beneficial purposes of ozone such as elimination of odours, harmful bacteria and mildew can be used for transportation of food, fruits and vegetables with the aim to extend their storage life. To date the main technique used for this purpose in the transportation of these commodities, e.g. by trucks, was cooling. Here a combination of cooling together with the supply of ozone into containers with these commodities is considered. For these purposes we studied the effect of air contamination by n-heptane (part of automotive fuels) and humidity on ozone production by a dc hollow needle to mesh corona discharge. We found that, for both polarities of the needle electrode, addition of n-heptane to air (a) decreases ozone production; (b) causes discharge poisoning to occur at lower current than for air; (c) does not substantially influence the current for which the ozone production reaches the maximum. Finally the maximum ozone production for the discharge in air occurs for the same current as the maximum ozone production for the discharge contaminated by n-heptane. We also found that humidity decreases ozone production from air contaminated by n-heptane irrespective of the polarity of the coronating needle electrode. This dependence is stronger for the discharge with the needle biased positively.

Measuring stream discharge by non-contact methods: A proof-of-concept experiment

USGS Publications Warehouse

Costa, J.E.; Spicer, K.R.; Cheng, R.T.; Haeni, F.P.; Melcher, N.B.; Thurman, E.M.; Plant, W.J.; Keller, W.C.

2000-01-01

This report describes an experiment to make a completely non-contact open-channel discharge measurement. A van-mounted, pulsed doppler (10GHz) radar collected surface-velocity data across the 183-m wide Skagit River, Washington at a USGS streamgaging station using Bragg scattering from short waves produced by turbulent boils on the surface of the river. Surface velocities were converted to mean velocities for 25 sub-sections by assuming a normal open-channel velocity profile (surface velocity times 0.85). Channel cross-sectional area was measured using a 100 MHz ground-penetrating radar antenna suspended from a cableway car over the river. Seven acoustic doppler current profiler discharge measurements and a conventional current-meter discharge measurement were also made. Three non-contact discharge measurements completed in about a 1-hour period were within 1 % of the gaging station rating curve discharge values. With further refinements, it is thought that open-channel flow can be measured reliably by non-contact methods.

Self-consistent modeling of self-organized patterns of spots on anodes of DC glow discharges

NASA Astrophysics Data System (ADS)

Bieniek, M. S.; Almeida, P. G. C.; Benilov, M. S.

2018-05-01

Self-organized patterns of spots on a flat metallic anode in a cylindrical glow discharge tube are simulated. A standard model of glow discharges is used, comprising conservation and transport equations for a single species of ion and electrons, written with the use of the drift-diffusion and local-field approximations, and the Poisson equation. Only processes in the near-anode region are considered and the computation domain is the region between the anode and the discharge column. Multiple solutions, existing in the same range of discharge current and describing modes with and without anode spots, are computed for the first time. A reversal of the local anode current density in the spots was found, i.e. mini-cathodes are formed inside the spots or, as one could say, anode spots operate as a unipolar glow discharge. The solutions do not fit into the conventional pattern of self-organization in bistable nonlinear dissipative systems; In particular, the modes are not joined by bifurcations.

Role of turbulence fluctuations on uncertainties of acoutic Doppler current profiler discharge measurements

USGS Publications Warehouse

Tarrab, Leticia; Garcia, Carlos M.; Cantero, Mariano I.; Oberg, Kevin

2012-01-01

This work presents a systematic analysis quantifying the role of the presence of turbulence fluctuations on uncertainties (random errors) of acoustic Doppler current profiler (ADCP) discharge measurements from moving platforms. Data sets of three-dimensional flow velocities with high temporal and spatial resolution were generated from direct numerical simulation (DNS) of turbulent open channel flow. Dimensionless functions relating parameters quantifying the uncertainty in discharge measurements due to flow turbulence (relative variance and relative maximum random error) to sampling configuration were developed from the DNS simulations and then validated with field-scale discharge measurements. The validated functions were used to evaluate the role of the presence of flow turbulence fluctuations on uncertainties in ADCP discharge measurements. The results of this work indicate that random errors due to the flow turbulence are significant when: (a) a low number of transects is used for a discharge measurement, and (b) measurements are made in shallow rivers using high boat velocity (short time for the boat to cross a flow turbulence structure).

Particle control and plasma performance in the Lithium Tokamak eXperimenta)

NASA Astrophysics Data System (ADS)

Majeski, R.; Abrams, T.; Boyle, D.; Granstedt, E.; Hare, J.; Jacobson, C. M.; Kaita, R.; Kozub, T.; LeBlanc, B.; Lundberg, D. P.; Lucia, M.; Merino, E.; Schmitt, J.; Stotler, D.; Biewer, T. M.; Canik, J. M.; Gray, T. K.; Maingi, R.; McLean, A. G.; Kubota, S.; Peebles, W. A.; Beiersdorfer, P.; Clementson, J. H. T.; Tritz, K.

2013-05-01

The Lithium Tokamak eXperiment is a small, low aspect ratio tokamak [Majeski et al., Nucl. Fusion 49, 055014 (2009)], which is fitted with a stainless steel-clad copper liner, conformal to the last closed flux surface. The liner can be heated to 350 °C. Several gas fueling systems, including supersonic gas injection and molecular cluster injection, have been studied and produce fueling efficiencies up to 35%. Discharges are strongly affected by wall conditioning. Discharges without lithium wall coatings are limited to plasma currents of order 10 kA, and discharge durations of order 5 ms. With solid lithium coatings discharge currents exceed 70 kA, and discharge durations exceed 30 ms. Heating the lithium wall coating, however, results in a prompt degradation of the discharge, at the melting point of lithium. These results suggest that the simplest approach to implementing liquid lithium walls in a tokamak—thin, evaporated, liquefied coatings of lithium—does not produce an adequately clean surface.

The influence of NH3 on NO2 conversion in a dc corona discharge in N2:O2:CO2:NO2:NH3 mixture

NASA Astrophysics Data System (ADS)

Dors, Mirosław; Mizeraczyk, Jerzy; Czech, Tadeusz; Konieczka, Jerzy

1996-10-01

The aim of this paper is to investigate the influence of NH3 additive (540-1470 ppm) on the conversion of NO2 and the creation of NO and N2O in a mixture of N2:O2:CO2: NO2:NH3 subjected to the so-called direct current (dc) corona discharge. The dc corona discharge was generated in a needle-to-plate reactor. Seven positively polarized needles were used as one electrode and a stainless steel plate as the other. The time-averaged discharge current was varied from 0 to 7 mA. It was found that the dc corona discharge decomposed NO2 and produced NO and N2O. The reduction of NO2 was higher without NH3 additive if the residence time of the operating gas was relatively short. However, in a longer corona discharge processing the NH3 additive may be useful for reduction of NO2.

Physiotherapy in the management of total knee arthroplasty: a review.

PubMed

Akodu, A K; Giwa, S O; Akinbo, S R A; Ahmed, U A

2011-01-01

Although total knee arthroplasty (TKA) is considered the treatment of choice for patients with intractable pain and substantial functional disabilities who have not had acceptable relief and functional improvement after conservative treatment. It was found out that patients with total knee arthroplasty need physiotherapy intervention for pre-operative and post-operative management. To take a critical look at the importance of TKA following destruction of the knee joint, its indications and contraindications and to ascertain the current trend involved in the physiotherapy management of TKA. The current literature materials on physiotherapy management of TKA was reviewed. The aim of treatment is to maximize functionality and independence and to minimize complication such as deep vein thrombosis and pulmonary embolism by relieving pain using cryotherapy, improving range of motion with mobilization techniques, muscle strengthening, therapeutic exercise, transfer training, gait training and training of activities of daily living. These are administered as home programme or in organized groups led by a physiotherapist and has been shown to improve outcome related to physical activity after knee joint arthroplasty. It was concluded that interventions, including physiotherapy and functional exercises after discharge, is still beneficial after TKA.

The effect of frequency on atmospheric pressure glow discharge in a pin-to-plate gap sustained by a resonant power supply

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

Wang, Yong Sheng; Ding, Wei Dong; Wang, Ya Nan

More and more researchers have been attracted to the research of atmospheric pressure glow discharge (APGD) because of its great prospect in numerous industrial applications. Nevertheless, almost all of the industrial applications are based on achievement of stable, large-volume, and uniform APGD. In a previous study, stable filamentary APGD was obtained by applying a resonant power supply between pin-to-plate electrodes which could limit the peak value of discharge current to supress the glow-to-arc transition through a series-wound resonance principle. The filamentary APGD is centimeter-level in the length but only several millimeters in diameter. Therefore, in order to obtain large-volume andmore » uniform APGD, it is significant to study how to diffuse filamentary APGD in radial direction. With the increasing resonant frequency of alternating current discharge, excited particles (mainly including energetic electrons and trapped ions left from the previous half-cycle discharge) in the electrodes gap increase, which benefits obtaining stable self-sustaining APGD. In this paper, mechanism and law of the influence of resonant frequency on the diffusion of filamentary APGD in ambient air were studied. By comparing the photos of discharge plasma and waveforms of the discharge voltage and current, it is found that the volume of the glow discharge plasma enlarges as the resonant frequency of the power supply increases. It is very significant and anticipating to study how to obtain stable, large-volume, and uniform APGD in ambient air by the resonant power supply.« less

Correcting acoustic Doppler current profiler discharge measurement bias from moving-bed conditions without global positioning during the 2004 Glen Canyon Dam controlled flood on the Colorado River

USGS Publications Warehouse

Gartner, J.W.; Ganju, N.K.

2007-01-01

Discharge measurements were made by acoustic Doppler current profiler at two locations on the Colorado River during the 2004 controlled flood from Glen Canyon Dam, Arizona. Measurement hardware and software have constantly improved from the 1980s such that discharge measurements by acoustic profiling instruments are now routinely made over a wide range of hydrologic conditions. However, measurements made with instruments deployed from moving boats require reliable boat velocity data for accurate measurements of discharge. This is normally accomplished by using special acoustic bottom track pings that sense instrument motion over bottom. While this method is suitable for most conditions, high current flows that produce downstream bed sediment movement create a condition known as moving bed that will bias velocities and discharge to lower than actual values. When this situation exists, one solution is to determine boat velocity with satellite positioning information. Another solution is to use a lower frequency instrument. Discharge measurements made during the 2004 Glen Canyon controlled flood were subject to moving-bed conditions and frequent loss of bottom track. Due to site conditions and equipment availability, the measurements were conducted without benefit of external positioning information or lower frequency instruments. This paper documents and evaluates several techniques used to correct the resulting underestimated discharge measurements. One technique produces discharge values in good agreement with estimates from numerical model and measured hydrographs during the flood. ?? 2007, by the American Society of Limnology and Oceanography, Inc.

Postoperative Calcium Management in Same-Day Discharge Thyroid and Parathyroid Surgery.

PubMed

Nelson, Kurt L; Hinson, Andrew M; Lawson, Bradley R; Middleton, Derek; Bodenner, Donald L; Stack, Brendan C

2016-05-01

To describe a safe and effective postoperative prophylactic calcium regimen for same-day discharge thyroid and parathyroid surgery. Case series with chart review. Tertiary referral academic institution. In total, 162 adult patients who underwent total thyroidectomy, completion thyroidectomy, unilateral parathyroidectomy, parathyroidectomy with bilateral neck exploration, or revision parathyroidectomy were identified preoperatively to be candidates for same-day discharge. All patients in this study were successfully discharged the same day on our standard prophylactic calcium regimen. Less than 1% (1/162) of patients re-presented to the hospital within 30 days of surgery, and that patient was successfully discharged from the emergency department after negative workup for hypocalcemia. There was no significant difference between preoperative and postoperative calcium levels in the total/completion thyroidectomy groups (9.3 vs 9.2 mg/dL, respectively; P = .14). The average postoperative calcium level in the parathyroid group was well within normal limits (9.5 mg/dL), and the difference in postoperative calcium levels between revision and primary parathyroidectomy cases was not significantly different (P = .34). The reported calcium regimen demonstrates a safe, effective, and objective means of postoperative calcium management in outpatient thyroid and parathyroid surgery in appropriately selected patients. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

Correlation of shoulder range of motion limitations at discharge with limitations in activities and participation one year later in persons with spinal cord injury.

PubMed

Eriks-Hoogland, Inge E; de Groot, Sonja; Post, Marcel W M; van der Woude, Lucas H V

2011-02-01

To study the correlation between limited shoulder range of motion in persons with spinal cord injury at discharge and the performance of activities, wheeling performance, transfers and participation one year later. Multicentre prospective cohort study. A total of 146 newly injured subjects with spinal cord injury. Shoulder range of motion was measured at discharge. One year later, Functional Independence Measure (FIM), transfer ability, wheelchair circuit and Physical Activity Scale for Individuals with Physical Disabilities (PASIPD) were assessed. Corrections were made for possible confounding factors (age, gender, level and completeness of injury, time since injury and shoulder pain). All subjects with limited shoulder range of motion at discharge had a lower FIM motor score and were less likely (total group 5 times, and subjects with tetraplegia 10 times less likely) to be able to perform an independent transfer one year later. Subjects with limited shoulder range of motion in the total group needed more time to complete the wheelchair circuit. No significant associations with the PASIPD were found in either group. Persons with spinal cord injury and limited shoulder range of motion at discharge are more limited in their activities one year later than those without limited shoulder range of motion.

Habitat sequencing and the importance of discharge in inferences

Treesearch

Robert H. Hilderbrand; A. Dennis Lemly; C. Andrew Dolloff

1999-01-01

The authors constructed stream maps for a low-­gradient trout stream in southwestern Virginia during autumn (base flow) and spring (elevated flows) to compare spatial and temporal variation in stream habitats. Pool-riffle sequencing and total area occupied by pools and riffles changed substantially depending on the level of discharge: reduced discharge resulted in an...

Theoretical and experimental investigation into high current hollow cathode arc attachment

NASA Astrophysics Data System (ADS)

Downey, Ryan T.

This research addresses several concerns of the mechanisms controlling performance and lifetime of high-current single-channel-hollow-cathodes, the central electrode and primary life-limiting component in Magnetoplasmadynamic thrusters. Specifically covered are the trends, and the theorized governing mechanisms, seen in the discharge efficiency and power, the size of the plasma attachment to the cathode (the active zone), cathode exit plume plasma density and energy, along with plasma property distributions of the internal plasma column (the IPC) of a single-channel-hollow-cathode. Both experiment and computational modeling were employed in the analysis of the cathodes. Employing Tantalum and Tungsten cathodes (of 2, 6 and 10 mm inner diameter), experiments were conducted to measure the temperature profile of operating cathodes, the width of the active zone, the discharge voltage, power, plasma arc resistance and efficiency, with mass flow rates of 50 to 300 sccm of Argon, and discharge currents of 15 to 50 Amps. Langmuir probing was used to obtain measurements for the electron temperature, plasma density and plasma potential at the cathode exit plane (down stream tip). A computational model was developed to predict the distribution of plasma inside the cathode, based upon experimentally determined boundary conditions. It was determined that the peak cathode temperature is a function of both interior cathode density and discharge current, though the location of the peak temperature is controlled gas density but not discharge current. The active zone width was found to be an increasing function of the discharge current, but a decreasing function of the mass flow rate. The width of the active zone was found to not be controlled by the magnitude of the peak cathode wall temperature. The discharge power consumed per unit of mass throughput is seen as a decreasing function of the mass flow rate, showing the increasing efficiency of the cathode. Finally, this new understanding of the mechanisms of the plasma attachment phenomena of a single-channel-hollow-cathode were extrapolated to the multi-channel-hollow-cathode environment, to explain performance characteristics of these devices seen in previous research.

Geographic information systems supporting the solution of emergencies and their connection to self-actuated notification systems

NASA Astrophysics Data System (ADS)

Reil, Adam; Bureš, Luděk; Roub, Radek; Hejduk, Tomáš; Novák, Pavel

2015-04-01

Geographic information systems represent an important tool in supporting the operation and crisis management of Integrated Rescue System (IRS) branches. The technology of geographic information systems makes it possible to localize specific information directly in the concerned area. A basic pre-requisite for efficient IRS functioning is the identification of so-called critical points in the given territory. The next step is the identification of endangered persons and properties. In these issues, emphasis is put particularly on the time scale, which represents a key aspect of the crisis management. In case of flood danger, the Early Flood Warning Service would inform flood authorities responsible for warning the population, declaring flood activity degrees, IRS activation and organization. For their decision-making, the flood authorities need data on level heights, current discharge rates and inundation areas. The information about discharge rates and height levels can be obtained from the network of recording stream gauge stations operated by the Czech Hydrometeorological Institute. Inundation areas are plotted in the flood control plans of municipalities, which however contain default information about areas flooded at the N-year flood discharges Q5, Q20 and Q100. Because of large intervals, these three scenarios are insufficient for the crisis management of larger communities and towns. Therefore, a data store was suggested that would include maps showing flow rate fields and inundation areas for a finer scale of flood discharges at regular intervals. The scale should be based on the N-year flood discharges with a possibility of extension if required by flood authorities. The discharge interval size should be selected with regard to the dynamics of level height change in the given watercourse. The inundation areas will be then established by way of calculation using the MIKE 21C 2D hydrodynamic model. The novel approach was applied recently in the cadastral area of Lety on the Berounka River. Two sets of certified maps were created: (1) The map of endangered properties 1 - grid of depths, and (2) The map of endangered properties 2 - grid of flow rates. The maps were created from the discharge of 500 m3/s to 1460 m3/s at intervals of 60 m3/s. Two additional discharge values were 1500 m3/s and a calibration discharge of 990 m3/s. In total, thirty-eight maps were created the foundation of which was an orthophotograph map where endangered properties were plotted together with inundation areas. The next step will now be a specific proposal for data store version. The data store will be placed on the web interface where scenarios will be possible to display according to the selected discharge. At the same time, information will be available about the current discharge in the given watercourse. The web interface will be publicly accessible and will be connected to IRS. This study was supported from the Project VG20132015127 as a part of the Security Research conducted by the Ministry of the Interior of the Czech Republic. Keywords: IRS, MIKE 21C, flood

Total pollution effect of urban surface runoff.

PubMed

Luo, Hongbing; Luo, Lin; Huang, Gu; Liu, Ping; Li, Jingxian; Hu, Sheng; Wang, Fuxiang; Xu, Rui; Huang, Xiaoxue

2009-01-01

For pollution research with regard to urban surface runoff, most sampling strategies to date have focused on differences in land usage. With single land-use sampling, total surface runoff pollution effect cannot be evaluated unless every land usage spot is monitored. Through a new sampling strategy known as mixed stormwater sampling for a street community at discharge outlet adjacent to river, this study assessed the total urban surface runoff pollution effect caused by a variety of land uses and the pollutants washed off from the rain pipe system in the Futian River watershed in Shenzhen City of China. The water quality monitoring indices were COD (chemical oxygen demand), TSS (total suspend solid), TP (total phosphorus), TN (total nitrogen) and BOD (biochemical oxygen demand). The sums of total pollution loads discharged into the river for the four indices of COD, TSS, TN, and TP over all seven rainfall events were very different. The mathematical model for simulating total pollution loads was established from discharge outlet mixed stormwater sampling of total pollution loads on the basis of four parameters: rainfall intensity, total land area, impervious land area, and pervious land area. In order to treat surface runoff pollution, the values of MFF30 (mass first flush ratio) and FF30 (first 30% of runoff volume) can be considered as split-flow control criteria to obtain more effective and economical design of structural BMPs (best management practices) facilities.

Feasibility of outpatient total hip and knee arthroplasty in unselected patients

PubMed Central

Gromov, Kirill; Kjærsgaard-Andersen, Per; Revald, Peter; Kehlet, Henrik; Husted, Henrik

2017-01-01

Background and purpose The number of patients who are suitable for outpatient total hip and knee arthroplasty (THA and TKA) in an unselected patient population remains unknown. The purpose of this prospective 2-center study was to identify the number of patients suitable for outpatient THA and TKA in an unselected patient population, to investigate the proportion of patients who were discharged on the day of surgery (DOS), and to identify reasons for not being discharged on the DOS. Patients and methods All consecutive, unselected patients who were referred to 2 participating centers and who were scheduled for primary THA and TKA were screened for eligibility for outpatient surgery with discharge to home on DOS. If patients did not fulfill the discharge criteria, the reasons preventing discharge were noted. Odds factors with relative risk intervals for not being discharged on DOS were identified while adjusting for age, sex, ASA score, BMI and distance to home. Results Of the 557 patients who were referred to the participating surgeons during the study period, 54% were potentially eligible for outpatient surgery. Actual DOS discharge occurred in 13–15% of the 557 patients. Female sex and surgery late in the day increased the odds of not being discharged on the DOS. Interpretation This study shows that even in unselected THA and TKA patients, same-day discharge is feasible in about 15% of patients. Future studies should evaluate safety aspects and economic benefits. PMID:28426262

Effect of the radio frequency discharge on the dust charging process in a weakly collisional and fully ionized plasma

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

Motie, Iman; Bokaeeyan, Mahyar, E-mail: Mehyar9798@gmail.com

2015-02-15

A close analysis of dust charging process in the presence of radio frequency (RF) discharge on low pressure and fully ionized plasma for both weak and strong discharge's electric field is considered. When the electromagnetic waves pass throughout fully ionized plasma, the collision frequency of the plasma is derived. Moreover, the disturbed distribution function of plasma particles in the presence of the RF discharge is obtained. In this article, by using the Krook model, we separate the distribution function in two parts, the Maxwellian part and the perturbed part. The perturbed part of distribution can make an extra current, so-calledmore » the accretion rate of electron (or ion) current, towards a dust particle as a function of the average electron-ion collision frequency. It is proven that when the potential of dust grains increases, the accretion rate of electron current experiences an exponential reduction. Furthermore, the accretion rate of electron current for a strong electric field is relatively smaller than that for a weak electric field. The reasons are elaborated.« less

Flood Discharge Analysis with Nakayasu Method Using Combination of HEC-RAS Method on Deli River in Medan City

NASA Astrophysics Data System (ADS)

Harahap, Rumilla; Jeumpa, Kemala; Hadibroto, Bambang

2018-03-01

The problem in this research is how in the rainy season the water does not overflow, does not occur flood and during the dry season does not occur drought so it can adjust the condition or existence of Deli river which is around Medan city. Deli River floods often occur, either caused by a smaller capacity than the existing discharge, lack of maintenance and drainage and disposal systems that do not fit with the environment, resulting in flood subscriptions every year. The purpose of this research is to know flood discharge at Deli river as Flood control in Medan city. This research is analyzed on several methods such as log Pearson, Gumbel and hydrograph unit, while HEC-RAS method is modeling conducted in analyzing the water profile of the Deli River. Furthermore, the calculation of the periodic flood discharge using the Nakayasu Method. Calculation result at Deli River return period flood discharge 2 years with an area of 14.8 km2 annual flood hydrograph the total is 26.79 m3/sec on the hours at the 4th time. Return period flood discharge 5 years with an area of 14.8 km2 annual flood hydrograph the total is 73,44 m3/sec. While 25 annual return period total flood hydrograph is 146.50 m3/sec. With flood analysis can reduce and minimize the risk of losses and land can be mapped if in the area there is flooding.