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Sample records for plasmodynamic plasma-focus discharges

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

    Energy Technology Data Exchange (ETDEWEB)

    Vinogradov, V. P.; Krauz, V. I., E-mail: krauz-vi@nrcki.ru [National Research Center Kurchatov Institute (Russian Federation); Mokeev, A. N. [Project Center ITER (Russian Federation); Myalton, V. V.; Kharrasov, A. M. [National Research Center Kurchatov Institute (Russian Federation)

    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.

  2. Simulation of electrical discharge in a 3.6 Joule miniature plasma focus device using SIMULINK

    Science.gov (United States)

    Jafari, Hossein; Habibi, Morteza

    2014-08-01

    A novel technique has been developed and studied in this paper to simulate the electrical discharge circuit of a 3.6 J miniature plasma focus device (PFD) and investigate the effect of inductance variation on voltage spike and current dip. The technique is based on a correlation between the electrical discharge circuit and plasma dynamics in a very small PFD that operates at the energy of 3.6 J. The simulation inputs include the charging voltage, capacitor bank capacitance, current limiter resistance, by-pass resistance as well as the time-dependent inductance and resistance of the plasma sheath which are calculated by assuming the plasma dynamics as transit times in going from one phase to the next. The variations of the most important elements in the circuit (i.e. the constant and breakdown inductances) and their effects on the current dip are studied in PFDs with low and high constant inductance. The model demonstrated for achieving a good pinch in the PFD, although the total inductance of the system should be low; however there is always an optimum inductance which causes an appropriate pinch. Furthermore, the electrical power produced by the pulsed power supply, the mechanical energy as well as the magnetic energy which are transferred into the plasma tube were obtained from simulation. The graph of electrical power demonstrated a high instantaneous increment in the power transferred into the plasma as one of the greatest advantages of the pulsed power supply. The simulation was performed using software tools within the MATLAB/SIMULINK simulation environment.

  3. Observation of plasma jets in a table top plasma focus discharge

    Energy Technology Data Exchange (ETDEWEB)

    Pavez, Cristian; Soto, Leopoldo, E-mail: lsoto@cchen.cl [Comisión Chilena de Energía Nuclear, CCHEN, Casilla 188-D, Santiago (Chile); Center for Research and Applications in Plasma Physics and Pulsed Power, P4, Santiago-Talca (Chile); Departamento de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andrés Bello, República 220, Santiago (Chile); Pedreros, José [Comisión Chilena de Energía Nuclear, CCHEN, Casilla 188-D, Santiago (Chile); Departamento de Ingeniería Eléctrica, Universidad de Santiago de Chile, Santiago (Chile); Tarifeño-Saldivia, Ariel [Comisión Chilena de Energía Nuclear, CCHEN, Casilla 188-D, Santiago (Chile); Center for Research and Applications in Plasma Physics and Pulsed Power, P4, Santiago-Talca (Chile)

    2015-04-15

    In the last years, medium size Z-pinch experiments operating at tens of kJ are being used to create supersonic plasma jets. Those experiments are produced with wire arrays and radial foils, and they are conducted in generators based on water-filled transmission lines. Also plasma jets have been observed in small X-pinch experiments operating at 1 kJ. In this work, observations of plasma jets produced in a table top plasma focus device by means of optical and digital interferometry are shown. The device was operated at only ∼70 J, achieving 50 kA in 150 ns. The plasma jets were observed after the pinch, in the region close and on the anode, along the axis. The electron density measured from the jets is in the range 10{sup 24}–10{sup 25 }m{sup −3}. From two consecutive plasma images separated 18 ns, the axial jet velocity was measured in the order of 4 × 10{sup 4 }m/s.

  4. Research on anisotropy of fusion-produced protons and neutrons emission from high-current plasma-focus discharges

    Energy Technology Data Exchange (ETDEWEB)

    Malinowski, K., E-mail: karol.malinowski@ncbj.gov.pl; Sadowski, M. J.; Szydlowski, A. [National Centre for Nuclear Research (NCBJ), 05-400 Otwock (Poland); Institute of Plasma Physics and Laser Microfusion (IFPiLM), 01-497 Warsaw (Poland); Skladnik-Sadowska, E.; Czaus, K.; Kwiatkowski, R.; Zaloga, D. [National Centre for Nuclear Research (NCBJ), 05-400 Otwock (Poland); Paduch, M.; Zielinska, E. [Institute of Plasma Physics and Laser Microfusion (IFPiLM), 01-497 Warsaw (Poland)

    2015-01-15

    The paper concerns fast protons and neutrons from D-D fusion reactions in a Plasma-Focus-1000U facility. Measurements were performed with nuclear-track detectors arranged in “sandwiches” of an Al-foil and two PM-355 detectors separated by a polyethylene-plate. The Al-foil eliminated all primary deuterons, but was penetrable for fast fusion protons. The foil and first PM-355 detector were penetrable for fast neutrons, which were converted into recoil-protons in the polyethylene and recorded in the second PM-355 detector. The “sandwiches” were irradiated by discharges of comparable neutron-yields. Analyses of etched tracks and computer simulations of the fusion-products behavior in the detectors were performed.

  5. Research on soft x-rays in high-current plasma-focus discharges and estimation of plasma electron temperature

    Science.gov (United States)

    Skladnik-Sadowska, E.; Zaloga, D.; Sadowski, M. J.; Kwiatkowski, R.; Malinowski, K.; Miklaszewski, R.; Paduch, M.; Surala, W.; Zielinska, E.; Tomaszewski, K.

    2016-09-01

    The paper presents results of experimental studies of dense and high-temperature plasmas, which were produced by pulsed high-current discharges within a modernised PF-1000U facility operated at different initial gas conditions, and supplied from a condenser bank which delivered energy of about 350 kJ. The investigated discharges were performed at the initial deuterium filling under pressure of 1.6-2.0 hPa, with or without an additional puffing of pure deuterium (1 cm3, under pressure 0.15 MPa, at instants 1.5-2 ms before the main discharge initiation). For a comparison discharges were also performed at the initial neon filling under pressure of 1.1-1.3 hPa, with or without the addition of deuterium puffing. The recorded discharge current waveforms, laser interferometric images, signals of hard x-rays and fusion neutrons, as well as time-integrated x-ray pinhole images and time-resolved x-ray signals were compared. From a ratio of the x-ray signals recorded behind beryllium filters of different thickness there were estimated values of a plasma electron temperature (T e) in a region at the electrode outlets. For pure deuterium discharges an averaged T e value amounted to 150-170 eV, while for neon discharges with the deuterium puffing it reached 330-880 eV (with accuracy of  ±20%).

  6. Optical emission spectroscopy of deuterium and helium plasma jets emitted from plasma focus discharges at the PF-1000U facility

    Science.gov (United States)

    Skladnik-Sadowska, E.; Dan'ko, S. A.; Kwiatkowski, R.; Sadowski, M. J.; Zaloga, D. R.; Paduch, M.; Zielinska, E.; Kharrasov, A. M.; Krauz, V. I.

    2016-12-01

    Optical emission spectroscopy techniques were used to investigate the spectra of dense deuterium-plasma jets generated by high-current pulse discharges within the large PF-1000U facility and to estimate parameters of plasma inside the jets and their surroundings. Time-resolved optical spectra were recorded by means of a Mechelle®900 spectrometer. From an analysis of the deuterium line broadening, it was estimated that the electron concentration at a distance 57 cm from the electrode outlets amounted to (0.4-3.7) × 1017 cm-3 depending on the initial gas distribution and the time interval of the spectrum registration after the instant of the plasma jet generation. From the re-absorption dip in the Dβ profile, it was assessed that the electron concentration in the surrounding gas was equal to about 1.5 × 1015 cm-3. On the basis of the measured ratio of He II 468.6 nm and He I 587.6 nm line intensities, it was estimated that the electron temperature amounted to about 5.3 eV. Also estimated were some dimensionless parameters of the investigated plasma jets.

  7. Energy- and time-resolved measurements of fast ions emitted from plasma-focus discharges by means of a Thomson spectrometer

    Science.gov (United States)

    Kwiatkowski, R.; Czaus, K.; Paduch, M.; Sadowski, M. J.; Skladnik-Sadowska, E.; Zaloga, D. R.; Zielinska, E.; Żebrowski, J.

    2015-09-01

    The paper presents results of time-resolved measurements of fast deuterons emitted from high-current discharges of the Plasma-Focus (PF) type. The measurements were performed in a modified PF-1000U facility which is operated at the IFPiLM in Warsaw, Poland. The device was equipped with a fast-acting gas valve placed inside the inner electrode and oriented along the z-axis. The valve could inject a small volume of a chosen gas in front of this electrode. The PF discharges were initiated at the initial deuterium pressure equal to 1.6 or 2 hPa, with or without the use of the gas-puffing. Such discharges emitted intense beams of accelerated primary ions and X-ray pulses as well as products of nuclear fusion reactions. The reported measurements of the fast ion beams were performed by means of a Thomson-type spectrometer located at a chosen distance at the z-axis and equipped with miniature scintillation detectors. These detectors were placed in different points upon the deuteron parabola which corresponded to determined energy values. The detectors configuration allowed us to determine instants of the ion emission (using a TOF technique) and to compare them with instants of the X-ray emission. The collected data provided important information about emission characteristics of the modified PF-1000U facility.

  8. Study of the interrelation between the electrotechnical parameters of the plasma focus discharge circuit and the plasma compression dynamics on the PF-3 and PF-1000 facilities

    Energy Technology Data Exchange (ETDEWEB)

    Mitrofanov, K. N., E-mail: mitrkn@inbox.ru [Troitsk Institute for Innovation and Fusion Research (Russian Federation); Krauz, V. I., E-mail: krauz-vi@nrcki.ru, E-mail: vkrauz@yandex.ru [National Research Centre Kurchatov Institute (Russian Federation); Grabovski, E. V. [Troitsk Institute for Innovation and Fusion Research (Russian Federation); Myalton, V. V.; Vinogradov, V. P. [National Research Centre Kurchatov Institute (Russian Federation); Paduch, M. [Institute of Plasma Physics and Laser Microfusion (Poland); Scholz, M. [Polish Academy of Sciences, Niewodniczański Institute of Nuclear Physics (Poland); Karpiński, L. [Łukasiewicz University of Technology, Faculty of Electrical and Computer Engineering (Poland)

    2015-05-15

    The main stages of the plasma current sheath (PCS) dynamics on two plasma focus (PF) facilities with different geometries of the electrode system, PF-3 (Filippov type) and PF-1000 (Mather type), were studied by analyzing the results of the current and voltage measurements. Some dynamic characteristics, such as the PCS velocity in the acceleration phase in the Mather-type facility (PF-1000), the moment at which the PCS reaches the anode end, and the plasma velocity in the radial stage of plasma compression in the PF-3 Filippov-type facility, were determined from the time dependence of the inductance of the discharge circuit with a dynamic plasma load. The energy characteristics of the discharge circuit of the compressing PCS were studied for different working gases (deuterium, argon, and neon) at initial pressures of 1.5–3 Torr in discharges with energies of 0.3–0.6 MJ. In experiments with deuterium, correlation between the neutron yield and the electromagnetic energy deposited directly in the compressed PCS was investigated.

  9. Dense Plasma Focus Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hui [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Li, Shengtai [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jungman, Gerard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hayes-Sterbenz, Anna Catherine [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-31

    The mechanisms for pinch formation in Dense Plasma Focus (DPF) devices, with the generation of high-energy ions beams and subsequent neutron production over a relatively short distance, are not fully understood. Here we report on high-fidelity 2D and 3D numerical magnetohydrodynamic (MHD) simulations using the LA-COMPASS code to study the pinch formation dynamics and its associated instabilities and neutron production.

  10. Influence of the Al wire placed in the anode axis on the transformation of the deuterium plasma column in the plasma focus discharge

    Science.gov (United States)

    Kubes, P.; Paduch, M.; Cikhardtova, B.; Cikhardt, J.; Klir, D.; Kravarik, J.; Rezac, K.; Zielinska, E.; Zaloga, D.; Sadowski, M. J.; Tomaszewski, K.

    2016-06-01

    In this paper, we describe the influence of an Al wire of 270 μm in diameter placed along the anode axis on the transformation of the deuterium pinch column in a megaampere (MA) plasma focus device. The evolution of the pinched column and of the wire corona was investigated by means of the multiframe interferometry, neutron and X-ray diagnostics. The wire corona did not influence considerably on the evolution of dense plasma structures and neutron production, but it increased the plasma density and consequently, the currents around its surface. The distribution of the closed internal currents (ranging hundreds of kA) and associated magnetic fields amounting to 5 T were also estimated in the dense plasma column and in plasmoidal structures at the near-equilibrium state. The description is based on the balance of the plasma pressure and the pressure of the internal poloidal and toroidal current components compressed by the external pinched column. The dominant number of fusion deuterium-deuterium (D-D) neutrons is produced during the evolution of instabilities, when the uninterrupted wire corona (containing deuterium) connects the dense structures of the pinch, and it did not allow the formation of a constriction of the sub-millimeter diameter.

  11. Theoretical Study of a Spherical Plasma Focus

    Science.gov (United States)

    Ay, Yasar

    A theoretical model is developed for two concentric electrodes spherical plasma focus device in order to investigate the plasma sheath dynamics, radiative emission, and the ion properties. The work focuses on the model development of the plasma sheath dynamics and its validation, followed by studying of the radiation effects and the beam-ion properties in such unique geometry as a pulsed source for neutrons, soft and hard x-rays, and electron and ion beams. Chapter 1 is an introduction on fusion systems including plasma focus. Chapter 2 is an extensive literature survey on plasma focus modeling and experiments including the various radiations and their mechanism. Chapter 3 details modeling and validation of the plasma sheath dynamics model with comparison between hydrogen, deuterium, tritium and deuterium-tritium mixture for the production of pulsed neutrons. Chapter 4 is a study of the radiative phase, in which neutron yield is investigated, as well as the predicted beam-ion properties. Chapter 5 summarizes and discusses the results. Chapter 6 provides concluding remarks and proposed future works. The phases of the developed model are the rundown phase I, rundown phase II, the reflected phase and a radiative phase. The rundown phase I starts immediately after the completion of the gas breakdown and ends when the current sheath reaches the equator point of the spherical shape. Then immediately followed by rundown phase II to start and it ends when the shock front hits the axis, which is the beginning of the reflected shock phase. Reflected shock front moves towards the incoming current sheath and meets it which is both the end of the reflected shock phase and the beginning of the radiative phase. After the reflected shock front and the current sheath meet, the current sheath continues to move radially inward by compressing the produced plasma column until it reaches the axis. Since the discharge current contains important information about the plasma dynamic

  12. Plasma focus in the limit of low energy

    Energy Technology Data Exchange (ETDEWEB)

    Silva, P.; Soto, L.; Sylvester, G.; Zambra, M. [Comision Chilena de Energia Nuclear, Casilla 188 D, Santiago (Chile); Bruzzone, H.; Clausse, A.; Moreno, C. [Red Interinstitucional de Plasmas Densos y Magnetizados, PLADEMA (Argentina)

    2002-07-01

    In order to achieve the design of a repetitive neutron pulses source for a substance detector, a single shot very small plasma focus device has been designed and constructed. The plasma focus operates in the limit of low energy (160 nF capacitor bank, 25-50 nH, 30-40 kV, 70-130 J). The design of the electrode was assisted by a simple model of a Mather plasma focus. A neutron yield of 10{sup 4} - 10{sup 5} is expected when the discharge is operated with deuterium. (Author)

  13. Experimental results of breakdown in "Dena" plasma focus device

    Science.gov (United States)

    Goudarzi, Shervin; Hoseinian, S. M.; Raeisdana, A.

    2014-06-01

    In spite of the intense research activities on Plasma Focus devices, the physics of the initial breakdown and surface discharge phase has not been realized completely. In this paper we have analyzed the surface discharge and initial breakdown phase in Filippov-type Plasma Focus Facility "Dena" (90 kJ, 25 kV) on the base of the current and current derivative measured signals by using Argon, Neon and Krypton as working gases at different discharge voltages and gas pressures, and the effects of working conditions (atomic weight, discharge voltage and gas pressure) on the breakdown and surface discharge phase have expressed. Also, on the base of these results, we have investigated about the relation of this phase with final pinch phase.

  14. Low voltage operation of plasma focus.

    Science.gov (United States)

    Shukla, Rohit; Sharma, S K; Banerjee, P; Das, R; Deb, P; Prabahar, T; Das, B K; Adhikary, B; Shyam, A

    2010-08-01

    Plasma foci of compact sizes and operating with low energies (from tens of joules to few hundred joules) have found application in recent years and have attracted plasma-physics scientists and engineers for research in this direction. We are presenting a low energy and miniature plasma focus which operates from a capacitor bank of 8.4 muF capacity, charged at 4.2-4.3 kV and delivering approximately 52 kA peak current at approximately 60 nH calculated circuit inductance. The total circuit inductance includes the plasma focus inductance. The reported plasma focus operates at the lowest voltage among all reported plasma foci so far. Moreover the cost of capacitor bank used for plasma focus is nearly 20 U.S. dollars making it very cheap. At low voltage operation of plasma focus, the initial breakdown mechanism becomes important for operation of plasma focus. The quartz glass tube is used as insulator and breakdown initiation is done on its surface. The total energy of the plasma focus is approximately 75 J. The plasma focus system is made compact and the switching of capacitor bank energy is done by manual operating switch. The focus is operated with hydrogen and deuterium filled at 1-2 mbar.

  15. Kinetic Simulations of Dense Plasma Focus Breakdown

    Science.gov (United States)

    Schmidt, A.; Higginson, D. P.; Jiang, S.; Link, A.; Povilus, A.; Sears, J.; Bennett, N.; Rose, D. V.; Welch, D. R.

    2015-11-01

    A dense plasma focus (DPF) device is a type of plasma gun that drives current through a set of coaxial electrodes to assemble gas inside the device and then implode that gas on axis to form a Z-pinch. This implosion drives hydrodynamic and kinetic instabilities that generate strong electric fields, which produces a short intense pulse of x-rays, high-energy (>100 keV) electrons and ions, and (in deuterium gas) neutrons. A strong factor in pinch performance is the initial breakdown and ionization of the gas along the insulator surface separating the two electrodes. The smoothness and isotropy of this ionized sheath are imprinted on the current sheath that travels along the electrodes, thus making it an important portion of the DPF to both understand and optimize. Here we use kinetic simulations in the Particle-in-cell code LSP to model the breakdown. Simulations are initiated with neutral gas and the breakdown modeled self-consistently as driven by a charged capacitor system. We also investigate novel geometries for the insulator and electrodes to attempt to control the electric field profile. The initial ionization fraction of gas is explored computationally to gauge possible advantages of pre-ionization which could be created experimentally via lasers or a glow-discharge. Prepared by LLNL under Contract DE-AC52-07NA27344.

  16. Preliminary Results Of A 600 Joules Small Plasma Focus Device

    Science.gov (United States)

    Lee, S. H.; Yap, S. L.; Wong, C. S.

    2009-07-01

    Preliminary results of a 600 J (3.7 μF, 18 kV) Mather type plasma focus device operated at low pressure will be presented. The discharge is formed between a solid anode with length of 6 cm and six symmetrically and coaxially arranged cathode rods of same lengths. The cathode base is profiled in a knife-edge design and a set of coaxial plasma gun are attached to it in order to initiate the breakdown and enhance the current sheath formation. The experiments have been performed in argon gas under a low pressure condition of several microbars. The discharge current and the voltage across the electrodes during the discharge are measured with high voltage probe and current coil. The current and voltage characteristics are used to determine the possible range of operating pressure that gives good focusing action. At a narrow pressure regime of 9.0±0.5 μbar, focusing action is observed with good reproducibility. Preliminary result of ion beam energy is presented. More work will be carried out to investigate the radiation output.

  17. Numerical Analysis of Amirkabir Plasma Focus (APF) Device for Neon and Argon Gases

    Science.gov (United States)

    Niknam Sharak, M.; Goudarzi, S.; Raeisdana, A.; Jafarabadi, M.

    2013-04-01

    In this paper the experimental results in different working conditions in Amirkabir Plasma Focus (APF) Device have been compared with the numerical results of a two-dimensional simulation code based on Lee's model. The experiments were done with pure Neon and Argon as operating gases over a wide range of working conditions (gas pressures and discharge voltages). It is observed that by a proper choice for values of the efficiency factors, comparison between numerical and experimental results shows a good agreement.

  18. Note: Repetitive operation of the capacitor bank of the low-voltage miniature plasma focus at 50 Hz

    Science.gov (United States)

    Shukla, Rohit; Shyam, Anurag

    2013-10-01

    We have already reported the low-voltage operation of a plasma focus describing the operation of plasma focus at 4.2 kV which proposes possibility of making a repetitive system using compact driving source. Another recent article describes that the same capacitor-bank can drive the plasma focus for a measured ˜5 × 104 neutrons per shot at 5 kV and 59 kA current. In the present work, repetitive operation of the capacitor-bank of plasma focus is done and that too is being reported at a very high repetition rate of 50 Hz using very simple scheme of charging and triggering the bank. The bank is continuously discharged to burst duration of 20 s in this configuration admeasuring a thousand shots.

  19. Simulations with Conventional and Gas Puff Plasma Focus Devices

    Science.gov (United States)

    Shan, Bing; Liu, Mahe; Lee, Paul; Lee, Sing

    2000-10-01

    An energy consistent plasma focus model is improved by considering the plasma ionization states based on the corona equilibrium. This provides the model with the capability of calculating the plasma dynamics and states for different gases in plasma focus. The model is employed to simulate the behavior of the NX2 plasma focus, with both neon and argon gases. The results show that much lower pressure is required to work with argon for x-ray. The model has also been modified to describe a gas-puff plasma focus based on a measured pressure distribution profile. The simulation result reveals that the gas-puff scheme is more efficient in plasma heating and can improve the stability of the plasma column. By comparing with the published results, agreements have been obtained between the computations and experiments of both machines in the major points regarding plasma dynamics, plasma column stability and appearances, plasma temperatures, and x-ray radiation properties.

  20. Design and Construction of a Dense Plasma Focus Device

    Science.gov (United States)

    1976-10-01

    breakdown phase ............ 6 3. Typical device waveforms ........ .................... . 11 4. Fluid models of pinch mechanisms...16 5. Ion trajectory models ........... ...................... 19 6. Fillipov-type plasma focus device ...... ................ ... 22 7...52 14a. Pulse amplifier .......... ......................... ... 56 14b. Triggering circuit for the thyratron tube and spark gap ........ 57 15

  1. Multi-scaling of the dense plasma focus

    Science.gov (United States)

    Saw, S. H.; Lee, S.

    2015-03-01

    The dense plasma focus is a copious source of multi-radiations with many potential new applications of special interest such as in advanced SXR lithography, materials synthesizing and testing, medical isotopes and imaging. This paper reviews the series of numerical experiments conducted using the Lee model code to obtain the scaling laws of the multi-radiations.

  2. Plasma motion observations in a very small plasma focus in the limit of low energy

    Energy Technology Data Exchange (ETDEWEB)

    Soto, L.; Silva, P.; Moreno, J. [Comision Chilena de Energia Nuclear, Casilla 188-D Santiago, (Chile); Altamirano, L. [Dicontek, Pasaje Galicia 11365, La Florida, Santiago (Chile); Clausse, A. [PLADEMA, UNCPBA Tandil and Comision Nacional de Energia Atomica (Argentina)

    2003-07-01

    A very small plasma focus device has been designed and constructed. The plasma focus operates in the limit of low energy (160 n F capacitor bank, 65 n H, 20 - 40 kV, {approx} 32 - 100 J). The design of the electrode was assisted by a simple model of a Mather plasma focus. A neutron yield of 10{sup 4} - 10{sup 5} is expected when the discharge is operated with deuterium. Experiments in H{sub 2} has been performed at pressures over the range 0.1 to 2 mbar. The diagnostics used in the experiments include current derivative, voltage monitor, and plasma image using a ICCD camera gated at 5 ns. The umbrella-like current sheath running over the end of the coaxial electrodes and the pinch after the radial collapse can be clearly observed in the photographs. The velocity of the radial collapse is of the order of 10{sup 5} m/s. The observations are similar to the results obtained with devices operating at energies several order of magnitude higher. (Author)

  3. Stark Broadening Analysis Using Optical Spectroscopy of the Dense Plasma Focus

    Science.gov (United States)

    Ross, Patrick; Bennett, Nikki; Dutra, Eric; Hagen, E. Chris; Hsu, Scott; Hunt, Gene; Koch, Jeff; Waltman, Tom; NSTec DPF Team

    2015-11-01

    To aid in validating numerical modeling of MA-class dense plasma focus (DPF) devices, spectroscopic measurements of the Gemini Dense Plasma Focus (DPF) were performed using deuterium and deuterium/dopant (argon/krypton) gas. The spectroscopic measurements were made using a fiber-coupled spectrometer and streak camera. Stark line-broadening analysis was applied to the deuterium beta emission (486 nm) in the region near the breakdown of the plasma and during the run-down and run-in phases of the plasma evolution. Densities in the range of 1e17 to low 1e18 cm-3 were obtained. These values are in agreement with models of the DPF performed using the LSP code. The spectra also show a rise and fall with time, indicative of the plasma sheath passing by the view port. Impurity features were also identified in the spectra which grew in intensity as the gas inside the DPF was discharged repeatedly without cycling. Implications of this impurity increase for D-T discharges (without fresh gas fills between every discharge) will be discussed. This work was done by National Security Technologies, LLC, under Contract No. DE-AC52-06NA25946, and by Los Alamos National Laboratory, under Contract no. DE-AC52-06NA25396 with the U.S. Department of Energy. DOE/NV/25946-2515.

  4. Modelling of the internal dynamics and density in a tens of joules plasma focus device

    Energy Technology Data Exchange (ETDEWEB)

    Marquez, Ariel [CNEA and Instituto Balseiro, 8402 Bariloche (Argentina); Gonzalez, Jose [INVAP-CONICET and Instituto Balseiro, 8402 Bariloche, Argentina. (Argentina); Tarifeno-Saldivia, Ariel; Pavez, Cristian; Soto, Leopoldo [CCHEN, Comision Chilena de Energia Nuclear, Casilla 188-D, Santiago (Chile); Center for Research and Applications in Plasma Physics and Pulsed Power, P4 (Chile); Clausse, Alejandro [CNEA-CONICET and Universidad Nacional del Centro, 7000 Tandil (Argentina)

    2012-01-15

    Using MHD theory, coupled differential equations were generated using a lumped parameter model to describe the internal behaviour of the pinch compression phase in plasma focus discharges. In order to provide these equations with appropriate initial conditions, the modelling of previous phases was included by describing the plasma sheath as planar shockwaves. The equations were solved numerically, and the results were contrasted against experimental measurements performed on the device PF-50J. The model is able to predict satisfactorily the timing and the radial electron density profile at the maximum compression.

  5. A compact plasma focus device and its neutron emission

    Institute of Scientific and Technical Information of China (English)

    王新新; 韩旻; 王志文; 刘坤

    1999-01-01

    A 2.2-kJ compact plasma focus device was developed and its characteristics of neutron emission were investigated. A maximum neutron yield of (3.1 ± 1.5) × 10~7 was obtained at 15 hPa deuterium filling pressure. It was found that the neutron yield Y_n is strongly correlated with the amplitude of the pinch dip in di/dt waveform. The time resolved measurement of the neutron pulse indicated that both the hard X-rays and the neutrons are emitted from plasma focus at the same instant and the width of neutron pulse (FWHM) changes slightly from 50 to 53 ns. The pinch time t_p varies from 1.5 to 16.5 ns and it is usually the case that the shorter t_p, the higher the neutron yield. It was also found that the squirrel cage cathode is better than the tubular cathode.

  6. Numerical Experiments Providing New Insights into Plasma Focus Fusion Devices

    Directory of Open Access Journals (Sweden)

    Sing Lee

    2010-04-01

    Full Text Available Recent extensive and systematic numerical experiments have uncovered new insights into plasma focus fusion devices including the following: (1 a plasma current limitation effect, as device static inductance is reduced towards very small values; (2 scaling laws of neutron yield and soft x-ray yield as functions of storage energies and currents; (3 a global scaling law for neutron yield as a function of storage energy combining experimental and numerical data showing that scaling deterioration has probably been interpreted as neutron ‘saturation’; and (4 a fundamental cause of neutron ‘saturation’. The ground-breaking insights thus gained may completely change the directions of plasma focus fusion research.

  7. Application of an impedance matching transformer to a plasma focus.

    Science.gov (United States)

    Bures, B L; James, C; Krishnan, M; Adler, R

    2011-10-01

    A plasma focus was constructed using an impedance matching transformer to improve power transfer between the pulse power and the dynamic plasma load. The system relied on two switches and twelve transformer cores to produce a 100 kA pulse in short circuit on the secondary at 27 kV on the primary with 110 J stored. With the two transformer systems in parallel, the Thevenin equivalent circuit parameters on the secondary side of the driver are: C = 10.9 μF, V(0) = 4.5 kV, L = 17 nH, and R = 5 mΩ. An equivalent direct drive circuit would require a large number of switches in parallel, to achieve the same Thevenin equivalent. The benefits of this approach are replacement of consumable switches with non-consumable transformer cores, reduction of the driver inductance and resistance as viewed by the dynamic load, and reduction of the stored energy to produce a given peak current. The system is designed to operate at 100 Hz, so minimizing the stored energy results in less load on the thermal management system. When operated at 1 Hz, the neutron yield from the transformer matched plasma focus was similar to the neutron yield from a conventional (directly driven) plasma focus at the same peak current.

  8. Experimental study of the performance of a very small repetitive plasma focus device in different working conditions

    Science.gov (United States)

    Goudarzi, S.; Babaee, H.; Esmaeli, A.; Nasiri, A.

    2017-01-01

    SORENA-1 is a very small repetitive Mather-type plasma focus device (20 J) that can operate at frequencies up to 1 Hz. This device has been designed and constructed in the Plasma and Nuclear Fusion Research School of the Nuclear Science and Technology Research Institute of Iran. In this article, the structure of SORENA-1 is described and results of experiments with Ar, Ne, and D2 working gases at several discharge voltages and initial pressures are presented and analyzed.

  9. Reliable Field Distortion Spark Gap for Plasma Focus

    Institute of Scientific and Technical Information of China (English)

    S.HUSSAIN; M.ZAKAULLAH

    2007-01-01

    A simple,low cost,easily maintained,and reliable field distortion spark gap has been developed to operate at a voltage up to 30 kV.The header construction necessary to attach the spark gap switch to a single 12.5μF,40 kV(10 kJ)capacitor is described.The main features of the spark gap are its wide range of voltage operation,high current capacity,low inductance and long lifetime.The performance of spark gap has been tested in a plasma focus and results are presented in this report.

  10. Development of a mobile and repetitive plasma focus

    Science.gov (United States)

    Rapezzi, L.; Angelone, M.; Pillon, M.; Rapisarda, M.; Rossi, E.; Samuelli, M.; Mezzetti, F.

    2004-05-01

    A plasma focus device aimed at working in environmental conditions not tailored for nuclear equipment has been developed by ENEA. It can operate in deuterium at 1 Hz shot rate, with an average neutron production of 3 × 108 neutrons/shot at 6 kJ of capacitor energy. It is easy to transport and conceived for those industrial purposes where a rather intense neutron generator is required but the use of tritium is forbidden. The machine is designed to be reliable and uniform in emission and to be operated in the field by personnel who are not specialists, to meet the requirements of the possible transformation into a commercial product.

  11. Research on pinches driven by Speed-2 generator: Hard X-ray and neutron emission in plasma focus configuration

    Energy Technology Data Exchange (ETDEWEB)

    Soto, L.; Moreno, J.; Silva, P.; Sylvester, G.; Zambra, M.; Pavez, C. [Comision Chilena de Energia Nuclear, Santiago (Chile); Pavez, C. [Universidad de Concepcion (Chile); Raspa, V. [Buenos Aires Univ., PLADEMA, CONICET and INFIP (Argentina); Castillo, F. [Insitituto de Ciencias Nucleares, UNAM (Mexico); Kies, W. [Heinrich-Heine-Univ., Dusseldorf (Germany)

    2004-07-01

    Speed-2 is a generator based on Marx technology and was designed in the University of Dusseldorf. Speed-2 consists on 40 +/- Marx modules connected in parallel (4.1 {mu}F equivalent Marx generator capacity, 300 kV, 4 MA in short circuit, 187 kJ, 400 ns rise time, dI/dt {approx} 10{sup 13} A/s). Currently Speed-2 is operating at CCHEN (Chilean nuclear energy commission), being the most powerful and energetic device for dense transient plasma in the Southern Hemisphere. Most of the previous works developed in Speed-2 at Dusseldorf were done in a plasma focus configuration for soft X-ray emission and the neutron emission from Speed-2 was not completely studied. The research program at CCHEN considers experiments in different pinch configurations (plasma focus, gas puffed plasma focus, gas embedded Z-pinch, wire arrays) at current of hundred of kilo- to mega-amperes, using the Speed-2 generator. The Chilean operation has begun implementing and developing diagnostics in a conventional plasma focus configuration operating in deuterium in order to characterize the neutron emission and the hard X-ray production. Silver activation counters, plastics CR39 and scintillator-photomultiplier detectors are used to characterize the neutron emission. Images of metallic plates with different thickness are obtained on commercial radiographic film, Agfa Curix ST-G2, in order to characterize an effective energy of the hard X-ray outside of the discharge. (authors)

  12. Radiography using a dense plasma focus device as a source of pulsed X-rays

    Science.gov (United States)

    Herrera, Julio; Castillo, Fermín; Gamboa, Isabel; Rangel, José

    2007-11-01

    Soft and hard X-ray emissions have been studied in the FN-II, which is a small dense plasma focus machine (5 kJ), operating at the Instituto de Ciencias Nucleares, UNAM, using aluminum filtered pin-hole cameras. Their angular distribution has been measured using TLD-200 dosimeters [1]. Their temporal evolution has been observed by means of a PIN diode, and scinltillators coupled to photomultipliers outside the discharge chamber. The X rays source can be concentrated by placing a needle on the end of the electrode. X-rays crossing across a 300 micron aluminum window, through the axis of the machine, can be used to obtain high contrast radiographs, with an average dose of 0.4 mGy per shot. In contrast, the average dose with a hollow cathode is 0.2 mGy per shot. This work is partially supported by grant IN105705 de la DGAPA-UNAM. [1] F. Castillo, J.J.E. Herrera, J. Rangel, I. Gamboa, G. Espinosa y J.I. Golzarri ``Angular Distribution of fusion products and X-rays emitted by a small dense plasma focus machine'' Journal of Applied Physics 101 013303-1-7 (2007).

  13. Imperative function of electron beams in low-energy plasma focus device

    Indian Academy of Sciences (India)

    M Z Khan; L K Lim; S L Yap; C S Wong

    2015-12-01

    A 2.2 kJ plasma focus device was analysed as an electron beam and an X-ray source that operates with argon gas refilled at a specific pressure. Time-resolved X-ray signals were observed using an array of PIN diode detectors, and the electron beam energy was detected using a scintillator-assisted photomultiplier tube. The resultant X-rays were investigated by plasma focus discharge for pressures ranging from 1.5 mbar to 2.0 mbar. This range corresponded to the significant values of X-ray yields and electron beam energies from the argon plasma. The electron temperature of argon plasma at an optimum pressure range was achieved by an indirect method using five-channel BPX65 PIN diodes of aluminum foils with different thicknesses. X-ray yield, electron beam energy, and electron temperature of argon plasma were achieved at 1.5–2.0 mbar because of the strong bombardment of the energetic electron beam.

  14. Study of soft X-ray emission during wire array implosion under plasma focus conditions at the PF-3 facility

    Energy Technology Data Exchange (ETDEWEB)

    Dan’ko, S. A. [National Research Centre Kurchatov Institute (Russian Federation); Mitrofanov, K. N., E-mail: mitrofan@triniti.ru [Troitsk Institute for Innovation and Fusion Research (Russian Federation); Krauz, V. I.; Myalton, V. V.; Zhuzhunashvili, A. I.; Vinogradov, V. P.; Kharrasov, A. M.; Anan’ev, S. S.; Vinogradova, Yu. V.; Kalinin, Yu. G. [National Research Centre Kurchatov Institute (Russian Federation)

    2015-11-15

    Results of measurements of soft X-ray emission with photon energies of <1 keV under conditions of a plasma focus (PF) experiment are presented. The experiments were carried out at the world’s largest PF device—the PF-3 Filippov-type facility (I ⩽ 3 MA, T/4 ≈ 15–20 µs, W{sub 0} ⩽ 3 MJ). X-ray emission from both a discharge in pure neon and with a tungsten wire array placed on the axis of the discharge chamber was detected. The wire array imploded under the action of the electric current intercepted from the plasma current sheath of the PF discharge in neon. The measured soft X-ray powers from a conventional PF discharge in gas and a PF discharge in the presence of a wire array were compared for the first time.

  15. Numerical Experiments on Oxygen Plasma Focus: Scaling Laws of Soft X-Ray Yields

    Science.gov (United States)

    Akel, M.

    2013-08-01

    Numerical experiments have been investigated on UNU/ICTP PFF low energy plasma focus device with oxygen filling gas. In these numerical experiments, the temperature window of 119-260 eV has been used as a suitable temperature range for generating oxygen soft X-rays. The Lee model was applied to characterize the UNU/ICTP PFF plasma focus. The optimum soft X-ray yield (Ysxr) was found to be 0.75 J, with the corresponding efficiency of about 0.03 % at pressure of 2.36 Torr and the end axial speed was va = 5 cm/μs. The practical optimum combination of p0, z0 and `a' for oxygen Ysxr was found to be 0.69 Torr, 4.8 cm and 2.366 cm respectively, with the outer radius b = 3.2 cm. This combination gives Ysxr ~ 5 J, with the corresponding efficiency of about 0.16 %. Thus we expect to increase the oxygen Ysxr of UNU/ICTP PFF, without changing the capacitor bank, merely by changing the electrode configuration and operating pressure. Scaling laws on oxygen soft X-ray yield, in terms of storage energies E0, peak discharge current Ipeak and focus pinch current Ipinch were found over the range from 1 kJ to 1 MJ. It was found that the oxygen soft X-ray yields scale well with and for the low inductance (L0 = 30 nH) (where yields are in J and currents in kA). While the soft X-ray yield scaling laws in terms of storage energies were found to be as (E0 in kJ and Ysxr in J) with the scaling showing gradual deterioration as E0 rises over the range. The oxygen soft X-ray yield emitted from plasma focus is found to be about 8.7 kJ for storage energy of 1 MJ. The optimum efficiency for soft X-ray yield (1.1 %) is with capacitor bank energy of 120 kJ. This indicates that oxygen plasma focus is a good soft X-ray source when properly designed.

  16. Characterization of bismuth nanospheres deposited by plasma focus device

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, M., E-mail: cscientific2@aec.org.sy [IBA Laboratory, Chemistry Department, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus (Syrian Arab Republic); Al-Hawat, Sh.; Akel, M. [Physics Department, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus (Syrian Arab Republic); Mrad, O. [Chemistry Department, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus (Syrian Arab Republic)

    2015-02-14

    A new method for producing thin layer of bismuth nanospheres based on the use of low energy plasma focus device is demonstrated. Various techniques such as scanning electron microscopy, Rutherford backscattering spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy have been used to characterize the morphology and the composition of the nanospheres. Experimental parameters may be adjusted to favour the formation of bismuth nanospheres instead of microspheres. Therefore, the formation of large surface of homogeneous layer of bismuth nanospheres with sizes of below 100 nm can be obtained. The natural snowball phenomenon is observed to be reproduced in nanoscale where spheres roll over the small nanospheres and grow up to bigger sizes that can reach micro dimensions. The comet-like structure, a reverse phenomenon to snowball is also observed.

  17. Fully kinetic simulations of megajoule-scale dense plasma focus

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, A.; Link, A.; Tang, V.; Halvorson, C.; May, M. [Lawrence Livermore National Laboratory, Livermore California 94550 (United States); Welch, D. [Voss Scientific, LLC, Albuquerque, New Mexico 87108 (United States); Meehan, B. T.; Hagen, E. C. [National Security Technologies, LLC, Las Vegas, Nevada 89030 (United States)

    2014-10-15

    Dense plasma focus (DPF) Z-pinch devices are sources of copious high energy electrons and ions, x-rays, and neutrons. Megajoule-scale DPFs can generate 10{sup 12} neutrons per pulse in deuterium gas through a combination of thermonuclear and beam-target fusion. However, the details of the neutron production are not fully understood and past optimization efforts of these devices have been largely empirical. Previously, we reported on the first fully kinetic simulations of a kilojoule-scale DPF and demonstrated that both kinetic ions and kinetic electrons are needed to reproduce experimentally observed features, such as charged-particle beam formation and anomalous resistivity. Here, we present the first fully kinetic simulation of a MegaJoule DPF, with predicted ion and neutron spectra, neutron anisotropy, neutron spot size, and time history of neutron production. The total yield predicted by the simulation is in agreement with measured values, validating the kinetic model in a second energy regime.

  18. Dense plasma focus (DPF) accelerated non radio isotopic radiological source

    Energy Technology Data Exchange (ETDEWEB)

    Rusnak, Brian; Tang, Vincent

    2017-01-31

    A non-radio-isotopic radiological source using a dense plasma focus (DPF) to produce an intense z-pinch plasma from a gas, such as helium, and which accelerates charged particles, such as generated from the gas or injected from an external source, into a target positioned along an acceleration axis and of a type known to emit ionizing radiation when impinged by the type of accelerated charged particles. In a preferred embodiment, helium gas is used to produce a DPF-accelerated He2+ ion beam to a beryllium target, to produce neutron emission having a similar energy spectrum as a radio-isotopic AmBe neutron source. Furthermore, multiple DPFs may be stacked to provide staged acceleration of charged particles for enhancing energy, tunability, and control of the source.

  19. Low Energy Plasma Focus as an Intense X-ray Source for Radiography

    Institute of Scientific and Technical Information of China (English)

    S. Hussain; M. Zakaullah; Shujaat Ali; A. Waheed

    2004-01-01

    Study on X-ray emission from a low energy (1.8 k J) plasma focus device powered by a 9 μF capacitor bank, charged at 20 kV and giving peak discharge current of about 175 kA by using a lead-inserted copper-tapered anode is reported. The X-ray yield in different energy windows is measured as a function of hydrogen filling pressure. The maximum yield in 4π-geometry is found to be (27.3±1.1) J and corresponding wall plug efficiency for X-ray generation is 1.52 ±0.06%. X-ray emission, presumably due to bombarding activity of electrons in current sheath at the anode tip was dominant, which is confirmed by the pinhole images. The feasibility of the device as an intense X-ray source for radiography is demonstrated.

  20. Counter-facing plasma focus system as an efficient and long-pulse EUV light source

    Science.gov (United States)

    Kuwabara, H.; Hayashi, K.; Kuroda, Y.; Nose, H.; Hotozuka, K.; Nakajima, M.; Horioka, K.

    2011-04-01

    A plasma focus system composed of a pair of counter-facing coaxial plasma guns is proposed as a long-pulse and efficient EUV light source. A proof-of-concept experiment demonstrated that with an assist of breakdown and outer electrode connections, current sheets evolved into a configuration for stable plasma confinement at the center of the electrode. The current sheets could successively compress and confine the high energy density plasma every half period of the discharge current, enabling highly repetitive light emissions in extreme ultraviolet region with time duration in at least ten microseconds for Xe plasma. Also, we confirmed operations of our system for Li plasma. We estimated the highest EUV energy in Li plasma operation at 93mJ/4π sr per 2% bandwidth per pulse.

  1. Understanding neutron production in the deuterium dense plasma focus

    Energy Technology Data Exchange (ETDEWEB)

    Appelbe, Brian, E-mail: b.appelbe07@imperial.ac.uk, E-mail: j.chittenden@imperial.ac.uk; Chittenden, Jeremy, E-mail: b.appelbe07@imperial.ac.uk, E-mail: j.chittenden@imperial.ac.uk [The Blackett Laboratory, Imperial College London, SW7 2AZ (United Kingdom)

    2014-12-15

    The deuterium Dense Plasma Focus (DPF) can produce copious amounts of MeV neutrons and can be used as an efficient neutron source. However, the mechanism by which neutrons are produced within the DPF is poorly understood and this limits our ability to optimize the device. In this paper we present results from a computational study aimed at understanding how neutron production occurs in DPFs with a current between 70 kA and 500 kA and which parameters can affect it. A combination of MHD and kinetic tools are used to model the different stages of the DPF implosion. It is shown that the anode shape can significantly affect the structure of the imploding plasma and that instabilities in the implosion lead to the generation of large electric fields at stagnation. These electric fields can accelerate deuterium ions within the stagnating plasma to large (>100 keV) energies leading to reactions with ions in the cold dense plasma. It is shown that the electromagnetic fields present can significantly affect the trajectories of the accelerated ions and the resulting neutron production.

  2. Opening switch research on a dense plasma focus

    Science.gov (United States)

    Gerdin, G.

    1987-02-01

    Experiments were performed to enhance power coupling to the load by placing the load electrode opposite the muzzle end of the Dense Plasma Focus plasma gun. The impaler concept, whereby the current sheath is run into a knife edge insulator, was tested in two configurations. However, the power coupled to the load was always less than one tenth that of the experiments where the load was coupled to the breach of the gun. Other load coupling schemes where the load electrode was brought near the outside of the central electrode prevented pinches (voltage surges) when placed too close and the power coupled to the load was reduced when the load electrodes were moved away. The results were not as good as those of the impaler concept. Measurements of the dynamics of the current sheath in various stages were performed and compared with theory. Generally the velocity of the current sheath falls below theoretical expectations suggesting the presence of electrode drag, a phenomenon not present in the model. During the radial collapse phase the model and the experimental estimates of dL/dt are in substantiaL agreement before pinch time but disagree afterward due to two dimensional effects not present in the theory.

  3. MHD modeling of dense plasma focus electrode shape variation

    Science.gov (United States)

    McLean, Harry; Hartman, Charles; Schmidt, Andrea; Tang, Vincent; Link, Anthony; Ellsworth, Jen; Reisman, David

    2013-10-01

    The dense plasma focus (DPF) is a very simple device physically, but results to date indicate that very extensive physics is needed to understand the details of operation, especially during the final pinch where kinetic effects become very important. Nevertheless, the overall effects of electrode geometry, electrode size, and drive circuit parameters can be informed efficiently using MHD fluid codes, especially in the run-down phase before the final pinch. These kinds of results can then guide subsequent, more detailed fully kinetic modeling efforts. We report on resistive 2-d MHD modeling results applying the TRAC-II code to the DPF with an emphasis on varying anode and cathode shape. Drive circuit variations are handled in the code using a self-consistent circuit model for the external capacitor bank since the device impedance is strongly coupled to the internal plasma physics. Electrode shape is characterized by the ratio of inner diameter to outer diameter, length to diameter, and various parameterizations for tapering. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  4. Current and Perspective Applications of Dense Plasma Focus Devices

    Science.gov (United States)

    Gribkov, V. A.

    2008-04-01

    Dense Plasma Focus (DPF) devices' applications, which are intended to support the main-stream large-scale nuclear fusion programs (NFP) from one side (both in fundamental problems of Dense Magnetized Plasma physics and in its engineering issues) as well as elaborated for an immediate use in a number of fields from the other one, are described. In the first direction such problems as self-generated magnetic fields, implosion stability of plasma shells having a high aspect ratio, etc. are important for the Inertial Confinement Fusion (ICF) programs (e.g. as NIF), whereas different problems of current disruption phenomenon, plasma turbulence, mechanisms of generation of fast particles and neutrons in magnetized plasmas are of great interest for the large devices of the Magnetic Plasma Confinement—MPC (e.g. as ITER). In a sphere of the engineering problems of NFP it is shown that in particular the radiation material sciences have DPF as a very efficient tool for radiation tests of prospect materials and for improvement of their characteristics. In the field of broad-band current applications some results obtained in the fields of radiation material sciences, radiobiology, nuclear medicine, express Neutron Activation Analysis (including a single-shot interrogation of hidden illegal objects), dynamic non-destructive quality control, X-Ray microlithography and micromachining, and micro-radiography are presented. As the examples of the potential future applications it is proposed to use DPF as a powerful high-flux neutron source to generate very powerful pulses of neutrons in the nanosecond (ns) range of its duration for innovative experiments in nuclear physics, for the goals of radiation treatment of malignant tumors, for neutron tests of materials of the first wall, blankets and NFP device's constructions (with fluences up to 1 dpa per a year term), and ns pulses of fast electrons, neutrons and hard X-Rays for brachytherapy.

  5. In situ determination of the static inductance and resistance of a plasma focus capacitor bank.

    Science.gov (United States)

    Saw, S H; Lee, S; Roy, F; Chong, P L; Vengadeswaran, V; Sidik, A S M; Leong, Y W; Singh, A

    2010-05-01

    The static (unloaded) electrical parameters of a capacitor bank are of utmost importance for the purpose of modeling the system as a whole when the capacitor bank is discharged into its dynamic electromagnetic load. Using a physical short circuit across the electromagnetic load is usually technically difficult and is unnecessary. The discharge can be operated at the highest pressure permissible in order to minimize current sheet motion, thus simulating zero dynamic load, to enable bank parameters, static inductance L(0), and resistance r(0) to be obtained using lightly damped sinusoid equations given the bank capacitance C(0). However, for a plasma focus, even at the highest permissible pressure it is found that there is significant residual motion, so that the assumption of a zero dynamic load introduces unacceptable errors into the determination of the circuit parameters. To overcome this problem, the Lee model code is used to fit the computed current trace to the measured current waveform. Hence the dynamics is incorporated into the solution and the capacitor bank parameters are computed using the Lee model code, and more accurate static bank parameters are obtained.

  6. Counter-facing plasma focus system as a repetitive and/or long-pulse high energy density plasma source

    Science.gov (United States)

    Aoyama, Yutaka; Nakajima, Mitsuo; Horioka, Kazuhiko

    2009-11-01

    A plasma focus system composed of a pair of counter-facing coaxial plasma guns is proposed as a long-pulse and/or repetitive high energy density plasma source. A proof-of-concept experiment demonstrated that with an assist of breakdown and outer electrode connections, current sheets evolved into a configuration for stable plasma confinement at the center of the electrodes. The current sheets could successively compress and confine the high energy density plasma every half period of the discharge current, enabling highly repetitive light emissions in extreme ultraviolet region with time durations in at least ten microseconds.

  7. Construction of a Compact, Low-Inductance, 100 J Dense Plasma Focus for Yield Optimization Studies

    Science.gov (United States)

    Cooper, Christopher; Povilus, Alex; Chapman, Steven; Falabella, Steve; Podpaly, Yuri; Shaw, Brian; Liu, Jason; Schmidt, Andrea

    2016-10-01

    A new 100 J mini dense plasma focus (DPF) is constructed to optimize neutron yields for a variety of plasma conditions and anode shapes. The device generates neutrons by leveraging instabilities that occur during a z-pinch in a plasma sheath to accelerate a beam of deuterium ions into a background deuterium gas target. The features that distinguish this miniDPF from previous 100 J devices are a compact, engineered electrode geometry and a low-impedance driver. The driving circuit inductance is minimized by mounting the capacitors close to the back of the anode and cathode yields. The anode can rapidly be changed out to test new designs. The neutron yield and 2D images of the visible light emission are compared to simulations with the hybrid kinetic code LSP which can directly simulate the device and anode designs. Initial studies of the sheath physics and neutron yields for a scaling of discharge voltages and neutral fill pressures are presented. Prepared by LLNL under Contract DE-AC52-07NA27344.

  8. Measurements of fast electron beams and soft X-ray emission from plasma-focus experiments

    Directory of Open Access Journals (Sweden)

    Surała Władysław

    2016-06-01

    Full Text Available The paper reports results of the recent experimental studies of pulsed electron beams and soft X-rays in plasma-focus (PF experiments carried out within a modified PF-360U facility at the NCBJ, Poland. Particular attention was focused on time-resolved measurements of the fast electron beams by means of two different magnetic analyzers, which could record electrons of energy ranging from about 41 keV to about 715 keV in several (6 or 8 measuring channels. For discharges performed with the pure deuterium filling, many strong electron signals were recorded in all the measuring channels. Those signals were well correlated with the first hard X-ray pulse detected by an external scintillation neutron-counter. In some of the analyzer channels, electron spikes (lasting about dozens of nanoseconds and appearing in different instants after the current peculiarity (so-called current dip were also recorded. For several discharges, fast ion beams, which were emitted along the z-axis and recorded with nuclear track detectors, were also investigated. Those measurements confirmed a multibeam character of the ion emission. The time-integrated soft X-ray images, which were taken side-on by means of a pinhole camera and sensitive X-ray films, showed the appearance of some filamentary structures and so-called hot spots. The application of small amounts of admixtures of different heavy noble gases, i.e. of argon (4.8% volumetric, krypton (1.6% volumetric, or xenon (0.8% volumetric, decreased intensity of the recorded electron beams, but increased intensity of the soft X-ray emission and showed more distinct and numerous hot spots. The recorded electron spikes have been explained as signals produced by quasi-mono-energetic microbeams emitted from tiny sources (probably plasma diodes, which can be formed near the observed hot spots.

  9. Hard X-ray sources from miniature plasma focus devices

    Energy Technology Data Exchange (ETDEWEB)

    Raspa, V. [Buenos Aires Univ., PLADEMA, CONICET and INFIP (Argentina); Silva, P.; Moreno, J.; Zambra, M.; Soto, L. [Comision Chilena de Energia Nuclear, Santiago (Chile)

    2004-07-01

    As first stage of a program to design a repetitive pulsed radiation generator for industrial applications, two miniature plasma foci have been designed and constructed at the Chilean commission of nuclear energy. The devices operate at an energy level of the order of tens of joules (PF-50 J, 160 nF capacitor bank, 20-35 kV, 32-100 J, {approx} 150 ns time to peak current) and hundred of joules (PF-400 J, 880 nF, 20-35 kV, 176-539 J, {approx} 300 ns time to peak current). Hard X-rays are being studied in these devices operating with hydrogen. Images of metallic plates with different thickness were obtained on commercial radiographic film, Agfa Curix ST-G2, in order to characterize the energy of the hard X-ray outside of the discharge chamber of PF-400 J. An effective energy of the order of 90 keV was measured under those conditions. X ray images of different metallic objects also have been obtained. (authors)

  10. Soft X-ray Emission Optimization Studies with Krypton and Xenon Gases in Plasma Focus Using Lee Model

    Science.gov (United States)

    Akel, Mohamad

    2013-10-01

    The X-ray emission properties of krypton and xenon plasmas are numerically investigated using corona plasma equilibrium model. Numerical experiments have been investigated on various low energy plasma focus devices with Kr and Xe filling gases using Lee model. The Lee model was applied to characterize and to find the optimum combination of soft X-ray yields (Ysxr) for krypton (~4 Å) and xenon (~3 Å) plasma focus. These combinations give Ysxr = 0.018 J for krypton, and Ysxr = 0.5 J for xenon. Scaling laws on Kr and Xe soft X-ray yields, in terms of storage energies E0, peak discharge current Ipeak and focus pinch current Ipinch were found over the range from 2.8 to 900 kJ. Soft X-ray yields scaling laws in terms of storage energies were found to be as and for Kr and Xe, respectively, (E0 in kJ and Ysxr in J) with the scaling showing gradual deterioration as E0 rises over the range. The maximum soft X-ray yields are found to be about 0.5 and 27 J from krypton and xenon, respectively, for storage energy of 900 kJ. The optimum efficiencies for soft X-ray yields (0.0002 % for Kr) and (0.0047 % for Xe) are with capacitor bank energies of 67.5 and 225 kJ, respectively.

  11. Demonstration of neutron production in a table-top pinch plasma focus device operating at only tens of joules

    Energy Technology Data Exchange (ETDEWEB)

    Soto, Leopoldo; Silva, Patricio; Moreno, Jose; Zambra, Marcelo; Pavez, Cristian [Comision Chilena de EnergIa Nuclear, Casilla 188-D, Santiago (Chile); Kies, Walter; Altamirano, Luis; Huerta, Luis [Center for Research and Applications in Plasma Physics and Pulsed Power, P4 (Chile); Mayer, Roberto E [Centro Atomico Bariloche and Instituto Balseiro, 8400 Bariloche (Argentina); Clausse, Alejandro [CNEA-CONICET and Universidad Nacional del Centro, 7000 Tandil (Argentina)], E-mail: lsoto@cchen.cl

    2008-10-21

    Neutron emission from a deuterium plasma pinch generated in a very small plasma focus (6 mm anode diameter) operating at only tens of joules is presented. A maximum current of 50 kA is achieved 140 ns after the beginning of the discharge, when the device is charged at 50 J (160 nF capacitor bank, 38 nH, 20-30 kV, 32-72 J). Although the stored energy is very low, the estimated energy density in the plasma and the energy per particle in the plasma are of the same order as in higher energy devices. The dependence of the neutron yield on the filling pressure of deuterium was obtained for discharges with 50 and 67 J stored in the capacitor bank. Neutrons were measured by means of a system based on a {sup 3}He proportional counter in current mode. The average neutron yield for 50 J discharges at 6 mbar was (1.2 {+-} 0.5) x 10{sup 4} neutrons per shot, and (3.6 {+-} 1.6) x 10{sup 4} for 67 J discharges at 9 mbar. The maximum energy of the neutrons was (2.7 {+-} 1.8) MeV. Possible applications related to substance detection and others are discussed.

  12. Nanofocus: an ultra-miniature dense pinch plasma focus device with submillimetric anode operating at 0.1 J

    Energy Technology Data Exchange (ETDEWEB)

    Soto, Leopoldo; Pavez, Cristian; Moreno, Jose [Comision Chilena de Energia Nuclear, Casilla 188-D, Santiago (Chile); Barbaglia, Mario; Clausse, Alejandro [CNEA-CONICET and Universidad Nacional del Centro, 7000 Tandil (Argentina)], E-mail: lsoto@cchen.cl

    2009-02-01

    As a method for investigating the minimum energy to produce a pinch plasma focus (PF) discharge, an ultra-miniature device for pinch discharges has been designed, constructed and characterized (nanofocus (NF): 5 nF, 5-10 kV, 5-10 kA, 60-250 mJ, 16 ns time to peak current). Submillimetric anode radii (0.8 and 0.21 mm) covered by coaxial insulators were used for experiments in hydrogen. Evidence of pinch was observed in electrical signals in discharges operating at 3 mbar and {approx}100 mJ. A single-frame image converter camera (4 ns exposure) was used to obtain plasma images in the visible range. The dynamics observed from the photographs is consistent with (a) the formation of a plasma sheath close to the insulator surface, (b) the plasma covering the anode, (c) radial compression over the anode; (d) finally the plasma is detached from the anode in the axial direction. The total time from stages (a) to (d) was observed in {approx}30 ns. This ultra-miniature device has a value for the 'plasma energy density parameter' and for the 'drive parameter' of the same order or greater than PF devices operating at energies several orders of magnitude higher.

  13. Concrete shielding of neutron radiations of plasma focus and dose examination by FLUKA

    Science.gov (United States)

    Nemati, M. J.; Amrollahi, R.; Habibi, M.

    2013-07-01

    Plasma Focus (PF) is among those devices which are used in plasma investigations, but this device produces some dangerous radiations after each shot, which generate a hazardous area for the operators of this device; therefore, it is better for the operators to stay away as much as possible from the area, where plasma focus has been placed. In this paper FLUKA Monte Carlo simulation has been used to calculate radiations produced by a 4 kJ Amirkabir plasma focus device through different concrete shielding concepts with various thicknesses (square, labyrinth and cave concepts). The neutron yield of Amirkabir plasma focus at varying deuterium pressure (3-9 torr) and two charging voltages (11.5 and 13.5 kV) is (2.25 ± 0.2) × 108 neutrons/shot and (2.88 ± 0.29) × 108 neutrons/shot of 2.45 MeV, respectively. The most influential shield for the plasma focus device among these geometries is the labyrinth concept on four sides and the top with 20 cm concrete.

  14. Dense plasma focus research at the Institute of Laser Engineering, Osaka (Japan)

    Science.gov (United States)

    Yokoyama, M.; Yamamoto, Y.; Kisoda, A.; Yamada, Y.; Kitagawa, Y.; Yamanaka, M.; Yamanaka, C.

    1983-09-01

    Research using a 50 kV/50 kJ deuterium plasma focus with 1.25 MA maximum current is summarized. Plasma dynamics in implosion phase of dense plasma focus were investigated by 2nsec ruby laser holographic interferometry and shadowgraphy. Radial pinch velocity of the plasma column and ionizing front velocity are 20 million cm/sec. Rayleigh-Taylor instability is observed in the early stage of the implosion phase. Effects of CO2 laser light on a dense plasma focus are discussed. High energy deuteron intensity, energy spectrum, and angular distribution were measured from radioactivity induced in graphite, aliminum and copper in ion dominant low pressure mode and neutron dominant high pressure mode.

  15. Dense Plasma Focus - From Alternative Fusion Source to Versatile High Energy Density Plasma Source for Plasma Nanotechnology

    Science.gov (United States)

    Rawat, R. S.

    2015-03-01

    The dense plasma focus (DPF), a coaxial plasma gun, utilizes pulsed high current electrical discharge to heat and compress the plasma to very high density and temperature with energy densities in the range of 1-10 × 1010 J/m3. The DPF device has always been in the company of several alternative magnetic fusion devices as it produces intense fusion neutrons. Several experiments conducted on many different DPF devices ranging over several order of storage energy have demonstrated that at higher storage energy the neutron production does not follow I4 scaling laws and deteriorate significantly raising concern about the device's capability and relevance for fusion energy. On the other hand, the high energy density pinch plasma in DPF device makes it a multiple radiation source of ions, electron, soft and hard x-rays, and neutrons, making it useful for several applications in many different fields such as lithography, radiography, imaging, activation analysis, radioisotopes production etc. Being a source of hot dense plasma, strong shockwave, intense energetic beams and radiation, etc, the DPF device, additionally, shows tremendous potential for applications in plasma nanoscience and plasma nanotechnology. In the present paper, the key features of plasma focus device are critically discussed to understand the novelties and opportunities that this device offers in processing and synthesis of nanophase materials using, both, the top-down and bottom-up approach. The results of recent key experimental investigations performed on (i) the processing and modification of bulk target substrates for phase change, surface reconstruction and nanostructurization, (ii) the nanostructurization of PLD grown magnetic thin films, and (iii) direct synthesis of nanostructured (nanowire, nanosheets and nanoflowers) materials using anode target material ablation, ablated plasma and background reactive gas based synthesis and purely gas phase synthesis of various different types of

  16. Theoretical and experimental study of inertial gases admixtures influence on the hard x-ray emission of plasma focus

    Science.gov (United States)

    Dulatov, A. K.; Lemeshko, B. D.; Mikhailov, Yu V.; Prokuratov, I. A.; Selifanov, A. N.

    2015-11-01

    This paper studies the influence of inertial gases admixtures (Ar, Kr, Xe) to deuterium in plasma focus (PF) chambers. Experiments were realized in PF chambers with discharge currents of 350, 650 and 1000 kA. The measurements of the hard x-ray (HXR) emission were carried out by the scintillation detector SSDI38 with time resolution of 2.5 ns. Experiments show the existence of optimum amount of inertial gases, which corresponds with the atomic number of added gas. At the optimum amount of inertial gas and deuterium in PF chamber, the HXR yield rises up to 10 times in comparison with HXR yield only for deuterium filling. This work shows the dependence of HXR emission on PF device stored energy. The mechanism of inertial gases admixtures influence that leads to rise of HXR yield has been discussed. The mechanism concerns with different behavior of deuterium ions and ions of inertial gases during the pinch decay phase when the discharge current compression force has reduced. Inertial gas ions locate near the axis of the pinch and deuterium ions go to the near plasma area. Local positive charge in plasma forms on this axis because of multiply charged ions of inertial gases. Then electrons gather to the axis area and electron density increases. This electrons form high current electron beam under the influence of the induced electromotive force during the pinch decay phase. HXR emission is generated after the electron beam interaction with the anode target in PF chamber.

  17. Compression between ion and hard x-ray emissions from nitrogen and argon in Mather type plasma focus device

    Directory of Open Access Journals (Sweden)

    S Paghe

    2016-12-01

    Full Text Available In this study, some characteristics of a Mather type Plasma Focus (PF device such as a discharge current, pinch time, ion flux and hard x-ray intensity has been investigated simultaneously in argon and nitrogen gases separately for various operating gas pressures and charging voltages of capacitor bank. It was observed that pinch phenomena was energy and pressure dependent in current sheath as well as ion and hard x-ray emission intensity. Optimum pressure with maximum ion flux and the most intense hard x-ray showed a nearly linear dependence on the charging voltage of the device. Maximum ion flux was estimated in the order of 1018 ions per steradian in both gases. Hard x-ray emission was registered a little after discharge current and Faraday cup (FC signals. Also, optimum pressure for maximum ion flux was not the same as the pressure for intense hard x-rays. Hard x-ray intensity reached its peak at higher pressures

  18. Statistical characterization of the reproducibility of neutron emission of small plasma focus devices

    Energy Technology Data Exchange (ETDEWEB)

    Tarifeno-Saldivia, Ariel; Soto, Leopoldo [Comision Chilena de Energia Nuclear (CCHEN), Casilla 188-D, Santiago (Chile); Center for Research and Applications in Plasma Physics and Pulsed Power, P4 (Chile) and Departamento de Ciencias Fisicas, Universidad Andres Bello, Republica 220, Santiago (Chile)

    2012-09-15

    The purpose of this work is to discuss the techniques related to the detection of fast pulsed neutrons produced in plasma focus (PF) devices, the statistical analysis of the corresponding data, and the methodologies for evaluation of the device performance in low emission neutron sources. A general mathematical framework is presented for the assessment of the reproducibility of the neutron emission of small PF devices given the shot-to-shot distribution and detector efficiency. The effect on the reproducibility in case of using two independent detectors is also discussed. The analysis is applied to the neutron emission of the plasma focus device PF-50J operating in repetitive mode (0.1-0.5 Hz and 65 J bank energy).

  19. Neutron and Ion Beams Emitted from Plasma Focus (112.5 J) Device

    Science.gov (United States)

    El-Aragi M., G.

    2010-02-01

    Preliminary results of recent experiments performed within the Mather-type 112.5 J plasma focus device are presented. The ion beams from the focus device operated with deuterium filling at 1 mbar were registered using CR-39 solid state nuclear track detectors (SSNTD) and a Faraday cup detector for time-resolved measurements. The time-resolved neutron emission from the focus region measurements was detected with a photomultiplier tube (IP-28) optically coupled with a plastic scintillator NE 102.

  20. X-ray emission from a small 2 kJ plasma focus

    Science.gov (United States)

    Beg, F. N.; Ross, I.; Dangor, A. E.

    1997-05-01

    We report on a study of a 2 kJ, 200 kA plasma focus device as an x-ray source. The x-ray yield from a number of pure gases, deuterium, nitrogen, neon, argon, and xenon, was measured as a function of pressure. X-ray emission is mainly due to line radiation. Maximum x-ray yield of 12.5 J obtained for neon. At lower pressures, electron beams are generated which play an important role.

  1. Comparison of measured and computed radial trajectories of plasma focus devices UMDPF1 and UMDPF0

    Energy Technology Data Exchange (ETDEWEB)

    Lim, L. H.; Yap, S. L., E-mail: yapsl@um.edu.my; Lim, L. K.; Lee, M. C.; Poh, H. S.; Ma, J. [Plasma Technology Research Centre, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Yap, S. S. [UMPEDAC, University of Malaya, 50603 Kuala Lumpur (Malaysia); Faculty of Engineering, Multimedia University, Cyberjaya, 63100 Selangor (Malaysia); Lee, S. [Plasma Technology Research Centre, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); INTI International University, 71800 Nilai (Malaysia); Institute for Plasma Focus Studies, 32 Oakpark Drive, Chadstone 3148 (Australia)

    2015-09-15

    In published literature, there has been scant data on radial trajectory of the plasma focus and no comparison of computed with measured radial trajectory. This paper provides the first such comparative study. We compute the trajectories of the inward-moving radial shock and magnetic piston of UMDPF1 plasma focus and compare these with measured data taken from a streak photograph. The comparison shows agreement with the measured radial trajectory in terms of average speeds and general shape of trajectory. This paper also presents the measured trajectory of the radially compressing piston in another machine, the UMDPF0 plasma focus, confirming that the computed radial trajectory also shows similar general agreement. Features of divergence between the computed and measured trajectories, towards the end of the radial compression, are discussed. From the measured radial trajectories, an inference is made that the neutron yield mechanism could not be thermonuclear. A second inference is made regarding the speeds of axial post-pinch shocks, which are recently considered as a useful tool for damage testing of fusion-related wall materials.

  2. The effect of pre-ionization by a shunt resistor on the reproducibility of plasma focus x-ray emission

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, S [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Sadiq, Mehboob [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Shafiq, M [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Waheed, A [PINSTECH, PO Box 2151, 44000 Islamabad (Pakistan); Lee, P [Natural Sciences Academics Group, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, 637616 (Singapore); Zakaullah, M [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan)

    2006-08-15

    The effect of pre-ionization by means of a shunt resistor on the x-ray emission of a low energy (1.8 kJ) plasma focus device powered by a 9 {mu}F capacitor bank, charged at 20 kV and giving a peak discharge current of about 175 kA is investigated. Quantrad Si pin-diodes along with a suitable filter are employed as time-resolved x-ray detectors, whereas a multipinhole camera with absorption filters is used for time-integrated analysis. X-ray flux in 4{pi}-geometry is measured as a function of argon filling pressure with and without pre-ionization. It is found that appropriate selection of the shunt resistor increases shot-to-shot reproducibility of the x-ray emission as well as the stability of the pinch filament and broadens the x-ray pulse width. The x-ray emission is also enhanced by (45 {+-} 5)% at the optimum pressure.

  3. The Dense Plasma Focus Opportunities in Detection of Hidden Objects by Using Nanosecond Impulse Neutron Inspection System (NINIS)

    Science.gov (United States)

    Gribkov, V.; Dubrovsky, A.; Karpiński, L.; Miklaszewski, R.; Paduch, M.; Scholz, M.; StrzyŻewski, P.; Tomaszewski, K.

    2006-12-01

    Dense Plasma Focus device is proposed for use as a neutron source to generate very powerful pulses of neutrons in the nanosecond (ns) range of its duration. Our devices PF-6, recently put into operation at the Institute of Plasma Physics and Laser Microfusion, Warsaw, Poland, and PF-10 belonging to the Institute for Theoretical and Experimental Physics, Moscow, Russia, have energy storages in its capacitor banks 7.4 kJ and 13 kJ as a maximum. Operated with the DPF chambers of a special design they have a current maximum up to ˜760 kA with a quarter period of the discharge equal to 1 microsecond. They generate circa 109 of 2.5-MeV neutrons in one pulse of ≅ 10-ns duration when working with deuterium, what permit to expect 1011 14-MeV neutrons at their operation with DT-mixture. This feature gives a principal possibility to create a "single-shot detection system" for interrogation of hidden objects. It means that all necessary information will be received during a single bright pulse of neutrons having duration in a nanosecond range by means of the time-of-flight technique with a short flight base. It might be a base for the creation of the Nanosecond Impulse Neutron Inspection System (NINIS). These characteristics of the neutron source open a number of opportunities while interrogation time in this case would now depend only on the data-processing system.

  4. Knowing the dense plasma focus - The coming of age (of the PF) with broad-ranging scaling laws

    Science.gov (United States)

    Saw, S. H.; Lee, S.

    2017-03-01

    The dense plasma focus is blessed not only with copious multi-radiations ranging from electron and ion beams, x-rays both soft and hard, fusion neutrons D-D and D-T but also with the property of enhanced compression from radiative collapse leading to HED (high energy density) states. The Lee code has been used in extensive systematic numerical experiments tied to reality through fitting with measured current waveforms and verified through comparison of measured and computed yields and measurements of multi-radiation. The studies have led to establishment of scaling laws with respect to storage energy, discharge current and pinch currents for fusion neutrons, characteristic soft x-rays, all-line radiation and ion beams. These are summarized here together with a first-time presentation of a scaling law of radiatively enhanced compression as a function of atomic number of operational gas. This paper emphasizes that such a broad range of scaling laws signals the coming of age of the DPF and presents a reference platform for planning the many potential applications such as in advanced SXR lithography, materials synthesizing and testing, medical isotopes, imaging and energy and high energy density (HED).

  5. Palm top plasma focus device as a portable pulsed neutron source.

    Science.gov (United States)

    Rout, R K; Niranjan, Ram; Mishra, P; Srivastava, R; Rawool, A M; Kaushik, T C; Gupta, Satish C

    2013-06-01

    Development of a palm top plasma focus device generating (5.2 ± 0.8) × 10(4) neutrons∕pulse into 4π steradians with a pulse width of 15 ± 3 ns is reported for the first time. The weight of the system is less than 1.5 kg. The system comprises a compact capacitor bank, a triggered open air spark gap switch, and a sealed type miniature plasma focus tube. The setup is around 14 cm in diameter and 12.5 cm in length. The energy driver for the unit is a capacitor bank of four cylindrical commercially available electrolytic capacitors. Each capacitor is of 2 μF capacity, 4.5 cm in diameter, and 9.8 cm in length. The cost of each capacitor is less than US$ 10. The internal diameter and the effective length of the plasma focus unit are 2.9 cm and 5 cm, respectively. A DC to DC converter power supply powered by two rechargeable batteries charges the capacitor bank to the desired voltage and also provides a trigger pulse of -15 kV to the spark gap. The maximum energy of operation of the device is 100 J (8 μF, 5 kV, 59 kA) with deuterium gas filling pressure of 3 mbar. The neutrons have also been produced at energy as low as 36 J (3 kV) of operation. The neutron diagnostics are carried out with a bank of (3)He detectors and with a plastic scintillator detector. The device is portable, reusable, and can be operated for multiple shots with a single gas filling.

  6. Calibration constant of a silver activation counter used with plasma focus devices

    Directory of Open Access Journals (Sweden)

    GR Etaati

    2010-03-01

    Full Text Available The silver activation counters are commonly used for pulsed-neutron yield measurements especially in plasma focus devices. The counter normally consists of a Geiger-Muller tube along with silver foils and polyethylene (as a moderator, which is calibrated against an Am-Be radioisotope neutron source. The neutrons, after being slowed-down in the polyethylene, activate the silver foils. By measuring the foil activity with a Geiger-Muller counter, the neutron yield is determined. In the present paper, the activation counter’s calibration constant calculation using the MCNP4C code is explained. The calculated calibration constant is in good agreement with the experimental results.

  7. Hundred joules plasma focus device as a potential pulsed source for in vitro cancer cell irradiation

    Science.gov (United States)

    Jain, J.; Moreno, J.; Andaur, R.; Armisen, R.; Morales, D.; Marcelain, K.; Avaria, G.; Bora, B.; Davis, S.; Pavez, C.; Soto, L.

    2017-08-01

    Plasma focus devices may arise as useful source to perform experiments aimed to study the effects of pulsed radiation on human cells in vitro. In the present work, a table top hundred joules plasma focus device, namely "PF-400J", was adapted to irradiate colorectal cancer cell line, DLD-1. For pulsed x-rays, the doses (energy absorbed per unit mass, measured in Gy) were measured using thermoluminescence detectors (TLD-100 dosimeters). The neutron fluence and the average energy were used to estimate the pulsed neutron doses. Fifty pulses of x-rays (0.12 Gy) and fifty pulses of neutrons (3.5 μGy) were used to irradiate the cancer cells. Irradiation-induced DNA damage and cell death were assessed at different time points after irradiation. Cell death was observed using pulsed neutron irradiation, at ultralow doses. Our results indicate that the PF-400J can be used for in vitro assessment of the effect of pulsed radiation in cancer cell research.

  8. The Role of the Driver Circuit in the Neutron Yield of the Plasma Focus

    Science.gov (United States)

    Sears, Jason; Schmidt, Andrea; Link, Anthony; Welch, Dale

    2015-11-01

    Emperical observations have suggested that dense plasma focus (DPF) neutron yield increases with driver impedance. Using the particle-in-cell code LSP, we reproduce this trend in a kJ DPF, and demonstrate in detail how driver impedance is coupled to neutron output. We implement a 2-D model of the plasma focus including self-consistent circuit-driven boundary conditions. We show that m=0 growth is central to beam formation and is a chaotic, non-deterministic process. Neutrons are produced when high, short-lived electric fields in the low-density cavity of an m=0 mode accelerate a beam of ions into the dense downstream pinch region. Neutron yield is highest when the ion beam is generated within 50 ns of the pinch formation on axis, because at that time the pinch (target) density is highest. High driver impedance contributes to prompt beam formation in two ways. First, the high impedance driver, losing less energy to run-down, has a faster run-in velocity and hence larger Rayleigh-Taylor features that more readily seed the m=0 instability. Second, the shorter anode of the high-impedance driver retains less trailing mass in the run-down region and thus exhibits fewer and less parasitic restrikes. Prepared by LLNL under Contract DE-AC52-07NA27344.

  9. Assessment of image quality in x-ray radiography imaging using a small plasma focus device

    Science.gov (United States)

    Kanani, A.; Shirani, B.; Jabbari, I.; Mokhtari, J.

    2014-08-01

    This paper offers a comprehensive investigation of image quality parameters for a small plasma focus as a pulsed hard x-ray source for radiography applications. A set of images were captured from some metal objects and electronic circuits using a low energy plasma focus at different voltages of capacitor bank and different pressures of argon gas. The x-ray source focal spot of this device was obtained to be about 0.6 mm using the penumbra imaging method. The image quality was studied by several parameters such as image contrast, line spread function (LSF) and modulation transfer function (MTF). Results showed that the contrast changes by variations in gas pressure. The best contrast was obtained at a pressure of 0.5 mbar and 3.75 kJ stored energy. The results of x-ray dose from the device showed that about 0.6 mGy is sufficient to obtain acceptable images on the film. The measurements of LSF and MTF parameters were carried out by means of a thin stainless steel wire 0.8 mm in diameter and the cut-off frequency was obtained to be about 1.5 cycles/mm.

  10. Description of plasma focus current sheath as the Turner relaxed state of a Hall magnetofluid

    Science.gov (United States)

    Auluck, S. K. H.

    2009-12-01

    The central mystery of plasma focus research is the two orders-of-magnitude-higher-than-thermal fusion reaction rate and the fact that both the space-resolved neutron spectra and space-resolved reaction proton spectra show features which can be ascribed only to a rotational motion of the center-of-mass of the reacting deuteron population. It has been suggested earlier [S. K. H. Auluck, IEEE Trans. Plasma Sci. 25, 37 (1997)] that this and other experimental observations can be consistently explained in terms of a hypothesis involving rotation of the current carrying plasma annulus behind the imploding gas-dynamic shock. Such rotation (more generally, mass flow) is an in-built feature of relaxed state of a two-fluid plasma [R. N. Sudan, Phys. Rev. Lett. 42, 1277 (1979)]. Relaxation in the "Hall magnetofluid" approximation, in which the generalized Ohm's law includes the Hall effect term and the magnetic convection term but omits the contributions to the electric field from resistive dissipation, electron pressure gradient, thermoelectric effect, electron inertia, etc., has been extensively studied by many authors. In the present paper, Turner's [IEEE Trans. Plasma Sci. PS-14, 849 (1986)] degenerate solution for the relaxed state of the Hall magnetohydrodynamic plasma has been adapted to the case of an infinitely long annular current carrying plasma, a tractable idealization of the current sheath of a plasma focus. The resulting model is consistent with experimental values of ion kinetic energy and observation of predominantly radially directed neutron emission in good shots.

  11. Study of Neutron From a Dense Plasma Focus Paco Instrument by Means of Nuclear Tracks Detectors

    Directory of Open Access Journals (Sweden)

    M. Milanese

    2016-08-01

    Full Text Available A most interesting feature of dense plasma foci is the acceleration of charge particle at energy in the range of MeV per nucleon. Using deuterium gas, this devices produce fusion D-D reactions, generation fast neutron pulses (~ 2.5 MeV. The device used in the present work is a Mather-type dense plasma focus, called PACO. It is a 2kJ device at 31 kV, with an oxygen-free copper anode, 50 mm long with 40 mm diameter. The coaxial cathode is formed by ten copper rods arranged in a squirrel cage configuration at a radius of 50mm. The insulator in an annular Pyrex® tube located at the base of the anode. The energy store is provided by four 1 µF (40 kV, 40 nH capacitors in parallel. The plasma focus was operated at 1.5 mb deuterium gas pressure. Neutron and accelerated particles are analyzed with material detectors (CR-39 Lantrack® for different conditions. A detailed study is made of track diameters when the plastic is chemically etched with, 6N KOH at 60°C (±1 for 12 h.

  12. The plasma focus as a tool for plasma-wall-interaction studies

    Science.gov (United States)

    Ramos, G.; Martinez, M.; Herrera, J. J. E.; Castillo, F.

    2015-03-01

    The study of the interaction of magnetized plasmas with candidate materials for fusion reactors, as for example tungsten, is a main topic in fusion research. Many studies simulate the plasma wall interaction using ion beams, while only a few use plasma simulators. Plasma foci can produce dense magnetized plasmas of deuterium and helium among other species. We used the plasma focus Fuego-Nuevo II, to expose tungsten samples to deuterium and helium plasmas. The samples were analysed by means of SEM, RBS and NRA, evidencing surface erosion, surface melting and retention of deuterium in a shallow surface layer of 250 nm amounting 6.5·1016 D/cm2. The plasma temperature has been measured at the position of the samples using a triple Langmuir probe and compared to calculations of a snowplow model. The modelling of the electrode to reach desired plasma parameters is discussed.

  13. Low-Energy Plasma Focus Device as an Electron Beam Source

    Science.gov (United States)

    Seong Ling, Yap; Naresh Kumar, Nitturi; Lian Kuang, Lim; Chiow San, Wong

    2014-01-01

    A low-energy plasma focus device was used as an electron beam source. A technique was developed to simultaneously measure the electron beam intensity and energy. The system was operated in Argon filling at an optimum pressure of 1.7 mbar. A Faraday cup was used together with an array of filtered PIN diodes. The beam-target X-rays were registered through X-ray spectrometry. Copper and lead line radiations were registered upon usage as targets. The maximum electron beam charge and density were estimated to be 0.31 μC and 13.5 × 1016/m3, respectively. The average energy of the electron beam was 500 keV. The high flux of the electron beam can be potentially applicable in material sciences. PMID:25544952

  14. Time-resolved spectra of dense plasma focus using spectrometer, streak camera, and CCD combination

    Energy Technology Data Exchange (ETDEWEB)

    Goldin, F. J. [Livermore Operations, National Security Technologies, LLC, Livermore, California 94550 (United States); Meehan, B. T.; Hagen, E. C. [North Las Vegas Facility, National Security Technologies, LLC, North Las Vegas, Nevada 89030 (United States); Wilkins, P. R. [Lawrence Livermore National Laboratories, Livermore, California 94550 (United States)

    2010-10-15

    A time-resolving spectrographic instrument has been assembled with the primary components of a spectrometer, image-converting streak camera, and CCD recording camera, for the primary purpose of diagnosing highly dynamic plasmas. A collection lens defines the sampled region and couples light from the plasma into a step index, multimode fiber which leads to the spectrometer. The output spectrum is focused onto the photocathode of the streak camera, the output of which is proximity-coupled to the CCD. The spectrometer configuration is essentially Czerny-Turner, but off-the-shelf Nikon refraction lenses, rather than mirrors, are used for practicality and flexibility. Only recently assembled, the instrument requires significant refinement, but has now taken data on both bridge wire and dense plasma focus experiments.

  15. Time-Resolved Spectra of Dense Plasma Focus Using Spectrometer, Streak Camera, CCD Combination

    Energy Technology Data Exchange (ETDEWEB)

    F. J. Goldin, B. T. Meehan, E. C. Hagen, P. R. Wilkins

    2010-10-01

    A time-resolving spectrographic instrument has been assembled with the primary components of a spectrometer, image-converting streak camera, and CCD recording camera, for the primary purpose of diagnosing highly dynamic plasmas. A collection lens defines the sampled region and couples light from the plasma into a step index, multimode fiber which leads to the spectrometer. The output spectrum is focused onto the photocathode of the streak camera, the output of which is proximity-coupled to the CCD. The spectrometer configuration is essentially Czerny–Turner, but off-the-shelf Nikon refraction lenses, rather than mirrors, are used for practicality and flexibility. Only recently assembled, the instrument requires significant refinement, but has now taken data on both bridge wire and dense plasma focus experiments.

  16. Energy spectrum of argon ions emitted from Filippov type Sahand plasma focus

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadnejad, M.; Pestehe, S. J.; Mohammadi, M. A. [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Postal Code 5166614766, Tabriz (Iran, Islamic Republic of); Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz (Iran, Islamic Republic of)

    2013-07-15

    The energy and flux of the argon ions produced in Sahand plasma focus have been measured by employing a well-designed Faraday cup. The secondary electron emission effects on the ion signals are simulated and the dimensions of Faraday cup are optimized to minimize these effects. The measured ion energy spectrum is corrected for the ion energy loss and charge exchange in the background gas. The effects of the capacitor bank voltage and working gas pressure on the ion energy spectrum are also investigated. It has been shown that the emitted ion number per energy increases as the capacitor bank voltage increases. Decreasing the working gas pressure leads to the increase in the number of emitted ion per energy.

  17. Radiation protection of PFMA-1, a plasma focus for medical applications.

    Science.gov (United States)

    Fabbri, A; Frignani, M; Mannucci, S; Mostacci, D; Rocchi, F; Sumini, M; Teodori, F; Angeli, E; Tartari, A; Cucchi, G

    2007-12-01

    A plasma focus is being developed for breeding short-lived radionuclides. The different radiation protection issues and concerns posed by the machine once in operation are analysed and discussed. Activation is shown to be totally negligible and likewise neutron emission is found to pose no concern at all. The only source of radiation risk is found to rest in the radionuclides produced, 18F and 15 O, generating a peak exposure of 1.114 Sv y(-1) at the distance of closest approach of 2.5 m. Shielding to protect against this hazard is calculated to be 5 cm Pb or 54 cm concrete for the operation area and 5.5 cm Pb for the transportation flask.

  18. Analysis for Radiation and Shielding Dose in Plasma Focus Neutron Source Using FLUKA

    Science.gov (United States)

    Nemati, M. J.; Amrollahi, R.; Habibi, M.

    2012-06-01

    Monte Carlo simulations have been performed for the attenuation of neutron radiation produced at Plasma focus (PF) devices through various shielding design. At the test site it will be fired with deuterium and tritium (D-T) fusion resulting in a yield of about 1013 fusion neutrons of 14 MeV. This poses a radiological hazard to scientists and personnel operating the device. The goal of this paper was to evaluate various shielding options under consideration for the PF operating with D-T fusion. Shields of varying neutrons-shielding effectiveness were investigated using concrete, polyethylene, paraffin and borated materials. The most effective shield, a labyrinth structure, allowed almost 1,176 shots per year while keeping personnel under 20 mSV of dose. The most expensive shield that used, square shield with 100 cm concrete thickness on the walls and Borated paraffin along with borated polyethylene added outside the concrete allowed almost 15,000 shot per year.

  19. Preionization Techniques in a kJ-Scale Dense Plasma Focus

    Science.gov (United States)

    Povilus, Alexander; Shaw, Brian; Chapman, Steve; Podpaly, Yuri; Cooper, Christopher; Falabella, Steve; Prasad, Rahul; Schmidt, Andrea

    2016-10-01

    A dense plasma focus (DPF) is a type of z-pinch device that uses a high current, coaxial plasma gun with an implosion phase to generate dense plasmas. These devices can accelerate a beam of ions to MeV-scale energies through strong electric fields generated by instabilities during the implosion of the plasma sheath. The formation of these instabilities, however, relies strongly on the history of the plasma sheath in the device, including the evolution of the gas breakdown in the device. In an effort to reduce variability in the performance of the device, we attempt to control the initial gas breakdown in the device by seeding the system with free charges before the main power pulse arrives. We report on the effectiveness of two techniques developed for a kJ-scale DPF at LLNL, a miniature primer spark gap and pulsed, 255nm LED illumination. Prepared by LLNL under Contract DE-AC52-07NA27344.

  20. Ion beam and neutron output from a sub-kilojoule dense plasma focus

    Energy Technology Data Exchange (ETDEWEB)

    Ellsworth, J. L., E-mail: ellsworth7@llnl.gov; Falabella, S., E-mail: ellsworth7@llnl.gov; Schmidt, A., E-mail: ellsworth7@llnl.gov; Tang, V., E-mail: ellsworth7@llnl.gov [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)

    2014-12-15

    We are seeking to gain a better fundamental understanding of the ion beam acceleration and neutron production dense plasma focus (DPF) device. Experiments were performed on a kilojoule level, fast rise time DPF located at LLNL. Ion beam spectra and neutron yield were measured for deuterium pinches. Visible light images of the pinch are used to determine the pinch length. In addition, an RF probe was placed just outside the cathode to measure fluctuations in E{sub z} up to 6 GHz, which is within the range of the lower hybrid frequencies. We find these oscillations arise at a characteristic frequency near 4 GHz during the pinch. Comparisons of the neutron yield and ion beam characteristics are presented. The neutron yield is also compared to scaling laws.

  1. Advances towards pB11 Fusion with the Dense Plasma Focus

    CERN Document Server

    Lerner, Eric J

    2007-01-01

    The prospects for achieving net energy production with pB11 fuel have recently considerably brightened. Studies have shown that the multi-GG field potentially obtainable with modest dense plasma focus devices have the effect of reducing the flow of energy from the ions to the electrons and thus suppressing bremsstrahlung radiation that cools the plasma. We report here on new simulations that indicate that net energy production may be achievable in high-magnetic-field devices at peak currents as low as 2.3 MA. While these simulations only model the dense plasmoid formed in the focus, new simulation techniques can allow a full particle-in-cell simulation of DPF functioning over the wide range of time and space scales needed. Such simulations will be of great value in the next round of experiments that will use pB11 fuel.

  2. Feasibility analysis of a Plasma Focus neutron source for BNCT treatment of transplanted human liver

    Science.gov (United States)

    Benzi, V.; Mezzetti, F.; Rocchi, F.; Sumini, M.

    2004-01-01

    Boron Neutron Capture Therapy preliminary treatments on transplanted human liver have been recently conducted at Pavia University. The need of high fluences of thermal neutrons imposed the use of the available thermal channel of a TRIGA reactor properly modified for this application. We analyse the possibility of using the Plasma Focus (PF) machine as a pulsed neutron source for this medical application instead of a nuclear reactor. Thermalization of the fast (2.45 MeV for D-D reactions) neutrons produced by the PF is gained with a paraffin or polyethylene moderator which contains both the neutron source and the irradiation chamber. The design parameters of a PF optimized for such an application are discussed, as well as other considerations on the advantages that this machine can bring to this kind of cancer therapy.

  3. Dense Plasma Focus Z-pinches for High Gradient Particle Acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Tang, V; Adams, M L; Rusnak, B

    2009-07-24

    The final Z-pinch stage of a Dense Plasma Focus (DPF) could be used as a simple, compact, and potentially rugged plasma-based high-gradient accelerator with fields at the 100 MV/m level. In this paper we review previously published experimental beam data that indicate the feasibility of such an DPF-based accelerator, qualitatively discuss the physical acceleration processes in terms of the induced voltages, and as a starting point examine the DPF acceleration potential by numerically applying a self-consistent DPF system model that includes the induced voltage from both macroscopic and instability driven plasma dynamics. Applications to the remote detection of high explosives and a multi-staged acceleration concept are briefly discussed.

  4. Energy spectrum of argon ions emitted from Filippov type Sahand plasma focus

    Science.gov (United States)

    Mohammadnejad, M.; Pestehe, S. J.; Mohammadi, M. A.

    2013-07-01

    The energy and flux of the argon ions produced in Sahand plasma focus have been measured by employing a well-designed Faraday cup. The secondary electron emission effects on the ion signals are simulated and the dimensions of Faraday cup are optimized to minimize these effects. The measured ion energy spectrum is corrected for the ion energy loss and charge exchange in the background gas. The effects of the capacitor bank voltage and working gas pressure on the ion energy spectrum are also investigated. It has been shown that the emitted ion number per energy increases as the capacitor bank voltage increases. Decreasing the working gas pressure leads to the increase in the number of emitted ion per energy.

  5. MCNP Simulation to Hard X-Ray Emission of KSU Dense Plasma Focus Machine

    CERN Document Server

    Mohamed, Amgad E

    2015-01-01

    The MCNP program used to simulate the hard x-ray emission from KSU dense plasma focus device, an electron beam spectrum of maximum energy 100 keV was used to hit anode target. The bremsstrahlung radiation was measured using the F2 tally functions on the chamber walls and on a virtual sphere surrounding the machine, the radiation spectrum was recorded for various anode materials like tungsten, stainless steel and molybdenum. It was found that tungsten gives the best and the most intense radiation for the same electron beam. An aluminum filter of thickness 2mm and 4mm was used to cutoff the lower energy band from the x-ray spectrum. It was found that the filters achieved the mission and there is no distinct difference in between.

  6. Neutron angular distribution in a plasma focus obtained using nuclear track detectors.

    Science.gov (United States)

    Castillo-Mejía, F; Herrera, J J E; Rangel, J; Golzarri, J I; Espinosa, G

    2002-01-01

    The dense plasma focus (DPF) is a coaxial plasma gun in which a high-density, high-temperature plasma is obtained in a focused column for a few nanoseconds. When the filling gas is deuterium, neutrons can be obtained from fusion reactions. These are partially due to a beam of deuterons which are accelerated against the background hot plasma by large electric fields originating from plasma instabilities. Due to a beam-target effect, the angular distribution of the neutron emission is anisotropic, peaked in the forward direction along the axis of the gun. The purpose of this work is to illustrate the use of CR-39 nuclear track detectors as a diagnostic tool in the determination of the time-integrated neutron angular distribution. For the case studied in this work, neutron emission is found to have a 70% contribution from isotropic radiation and a 30% contribution from anisotropic radiation.

  7. Low-Energy Plasma Focus Device as an Electron Beam Source

    Directory of Open Access Journals (Sweden)

    Muhammad Zubair Khan

    2014-01-01

    Full Text Available A low-energy plasma focus device was used as an electron beam source. A technique was developed to simultaneously measure the electron beam intensity and energy. The system was operated in Argon filling at an optimum pressure of 1.7 mbar. A Faraday cup was used together with an array of filtered PIN diodes. The beam-target X-rays were registered through X-ray spectrometry. Copper and lead line radiations were registered upon usage as targets. The maximum electron beam charge and density were estimated to be 0.31 μC and 13.5×1016/m3, respectively. The average energy of the electron beam was 500 keV. The high flux of the electron beam can be potentially applicable in material sciences.

  8. Design of a 500-kJ Mather-type plasma focus device

    Energy Technology Data Exchange (ETDEWEB)

    Heidarnia, A., E-mail: a-heidarnia@yahoo.com; Sadighzadeh, A.; Zaeem, A. A.; Damideh, V. [Nuclear Science and Technology Research Institute, Plasma Physics and Nuclear Fusion Research School (Iran, Islamic Republic of)

    2016-12-15

    In this article, design of a 500-kJ Mather-type plasma focus device to achieve 10{sup 11} neutrons/shot is reported. One of its important characteristics is the triple-part anode design. The anode is surrounded by an alumina insulator. The second part of the anode is changeable in order to locate cylindrical, conical, or other shapes of pieces mounted on it. This geometry leads to the easier investigation of the neutron and X-ray emissions of the device. The third part of the anode is for changing the materials exposed to different kinds of radiations. The design parameters are considered by semiempirical and empirical formulas and are sketched by Solidworks software. Also, the peak current and neutron yield are estimated.

  9. Design of a 500-kJ Mather-type plasma focus device

    Science.gov (United States)

    Heidarnia, A.; Sadighzadeh, A.; Zaeem, A. A.; Damideh, V.

    2016-12-01

    In this article, design of a 500-kJ Mather-type plasma focus device to achieve 1011 neutrons/shot is reported. One of its important characteristics is the triple-part anode design. The anode is surrounded by an alumina insulator. The second part of the anode is changeable in order to locate cylindrical, conical, or other shapes of pieces mounted on it. This geometry leads to the easier investigation of the neutron and X-ray emissions of the device. The third part of the anode is for changing the materials exposed to different kinds of radiations. The design parameters are considered by semiempirical and empirical formulas and are sketched by Solidworks software. Also, the peak current and neutron yield are estimated.

  10. Developing a plasma focus research training system for the fusion energy age

    Science.gov (United States)

    Lee, S.

    2014-08-01

    The 3 kJ UNU/ICTP Plasma Focus Facility is the most significant device associated with the AAAPT (Asian African Association for Plasma Training). In original and modified/upgraded form it has trained generations of plasma focus (PF) researchers internationally, producing many PhD theses and peer-reviewed papers. The Lee Model code was developed for the design of this PF. This code has evolved to cover all PF machines for design, interpretation and optimization, for derivation of radiation scaling laws; and to provide insights into yield scaling limitations, radiative collapse, speed-enhanced and current-stepped PF variants. As example of fresh perspectives derivable from this code, this paper presents new results on energy transfers of the axial and radial phases of generalized PF devices. As the world moves inexorably towards the Fusion Energy Age it becomes ever more important to train plasma fusion researchers. A recent workshop in Nepal shows that demand for such training continues. Even commercial project development consultants are showing interest. We propose that the AAAPT-proven research package be upgraded, by modernizing the small PF for extreme modes of operation, switchable from the typical strong-focus mode to a slow-mode which barely pinches, thus producing a larger, more uniform plasma stream with superior deposition properties. Such a small device would be cost-effective and easily duplicated, and have the versatility of a range of experiments from intense multi-radiation generation and target damage studies to superior advanced-materials deposition. The complementary code is used to reference experiments up to the largest existing machine. This is ideal for studying machine limitations and scaling laws and to suggest new experiments. Such a modernized versatile PF machine complemented by the universally versatile code would extend the utility of the PF experience; so that AAAPT continues to provide leadership in pulsed plasma research training in

  11. Laser-optical measurements of the velocities of the plasma jets formed from different gases in a kilojoule-range plasma focus facility

    Energy Technology Data Exchange (ETDEWEB)

    Polukhin, S. N., E-mail: snpol@lebedev.ru; Dzhamankulov, A. M.; Gurei, A. E.; Nikulin, V. Ya., E-mail: vnik@lebedev.ru; Peregudova, E. N.; Silin, P. V. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2016-12-15

    The velocities of the plasma jets formed from Ne, N{sub 2}, Ar, and Xe gases in plasma focus facilities were determined by means of laser-optical shadowgraphy of the shock waves generated at the jet leading edge. In spite of the almost tenfold ratio between the atomic weights of these gases, the outflow velocities of the plasma jets formed in experiments with these gases differ by less than twice, in the range of (0.7–1.1) × 10{sup 7} cm/s under similar discharge conditions. The energies of the jet ions were found to vary from 0.7 keV for nitrogen to 4 keV for xenon.

  12. Comparative study of radiation emission without and with target in a 2.2 kJ plasma focus device

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Muhammad Zubair, E-mail: mzubairkhan-um76@yahoo.com [Plasma Technology Research Center, Department of Physics, Faculty of Science, University Malaya, 50603 Kuala Lumpur Malaysia and Department of Physics, Federal Urdu University of Arts, Science and Technology, 45320 Islamabad (Pakistan); Ling, Yap Seong; San, Wong Chiow [Plasma Technology Research Center, Department of Physics, Faculty of Science, University Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-03-24

    The radiation emission in a 2.2 kJ Mather-type dense plasma focus device is investigated using a five channel BPX65 PIN diode spectrometer. Estimated X-ray associated with the hollow anode without and with target in Argon gas medium is compared. At optimum conditions, the radiation emission from the system is found to be strongly influenced with target in hollow anode and the filling gas pressure. The maximum X-ray yield in 4π sr was obtained in case of hollow anode in argon gas medium with target 'Lead' due to interaction of electron beam. Results indicated that an appropriate design of hollow anode with target could enhance the radiation emission by more intense interaction of expected electron beam with target. The outcomes are helpful in designing a plasma focus with enhanced X-ray radiation with improved shot to shot reproducibility in plasma focus device.

  13. Comparative study of X-ray emission from plasma focus relative to different preionization schemes

    Science.gov (United States)

    Ahmad, S.; Qayyum, A.; Hassan, M.; Zakaullah, M.

    2017-07-01

    A 2.7-kJ Mather-type plasma focus has been investigated for X-ray emission with preionization produced by an α-source, a β-source, and a shunt resistor. Time-resolved and time integrated measurements are carried out using a PIN-diode-based X-ray spectrometer and pinhole camera. The β-source (28Ni63) assisted preionization enhances the X-ray emission up to 25%, while preionization induced by depleted uranium (92U238) increases both Cu-Kα and total X-ray yield of about 100%. The preionization caused by the optimum shunt resistor enhances the Cu-Kα and total X-ray yield of about 53%. It is found that preionization also broadens the working pressure range for the high X-ray yield and improves the shot-to-shot reproducibility of the system. Pinhole images reveal that the X-ray emission from the anode tip is dominant owing to impact of electron bombardment, while the X-ray emission from hot spots is also visible.

  14. A new attempt using LabVIEW into a computational experiment of plasma focus device

    Science.gov (United States)

    Kim, Myungkyu

    2017-03-01

    The simulation program of plasma focus device based on S. Lee's model has been first developed since 30 years ago and it is widely used to date. Originally the program made by GWbasic language, and then modified by visual basic which was included in the Microsoft Excel. Using Excel well-known to researchers is a key advantage of this program. But it has disadvantages in displaying data in same graph, in slow calculation speed, and in displaying data and calculation of smaller time step. To overcome all these points, the LabVIEW that made by national instrument and based on graphical environment is used for simulation. Furthermore it is correlated with data acquisition of experiment, once experiment being the data is directly transferred to the simulation program and then analyzes and predicts for the next shot. The mass swept factor (fm) and current factor (fc) can be easily find out using this program. This paper describes the detail function and usage of the program and compares the results with the existing one.

  15. Neutron production with mixture of deuterium and krypton in Sahand Filippov type plasma focus facility

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, M.A., E-mail: mohammadidorbash@yahoo.com [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Tabriz (Iran, Islamic Republic of); Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz (Iran, Islamic Republic of); Sobhanian, S. [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Tabriz (Iran, Islamic Republic of); Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz (Iran, Islamic Republic of); Rawat, R.S. [Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University (Singapore)

    2011-08-01

    This Letter reports the order of magnitude enhancement in neutron yield from Sahand plasma focus device with krypton seeded deuterium operation. The highest average neutron yield of 2.2x10{sup 9} neutrons per shot was achieved at 1.00 Torr deuterium with 3% krypton which is higher than the best average neutron yield of 3.18x10{sup 8} neutrons per shot for pure deuterium operation. Estimation of average neutron energy showed that the maximum and minimum average energies are 2.98±0.6 MeV at 16 kV in 0.25 Torr deuterium with 3% Kr and 2.07±0.2 MeV at 18 kV operation in 0.5 Torr deuterium with 3% Kr, respectively. The anisotropy of neutron emission from Sahand DPF showed that the neutrons are produced mainly by beam-target mechanisms. -- Highlights: → The highest average neutron yield of 2.2x10{sup 9} neutrons per shot was achieved at mixture of deuterium and krypton. → In the krypton seeding of deuterium also anisotropy of neutron emission deuterium is found. → The krypton seeding of deuterium made the neutron emission more reliable over wider operating pressure ranges.

  16. Nanofocus of tenth of joules and a portable plasma focus of few joules for field applications

    Science.gov (United States)

    Soto, Leopoldo; Pavéz, Cristian; Moreno, José; Tarifeño, Ariel; Pedreros, José; Altamirano, Luis

    2009-01-01

    A repetitive pinch plasma focus that works with stored energy less than 1 J per shot has be developed at the Chilean Nuclear Energy Commission. The main features of this device, repetitive Nanofocus, are 5 nF of capacity, 5 nH of inductance, 5-10 kV charging voltage, 60-250 mJ stored energy, 5-10 kA current peak, per shot. The device has been operated at 20 Hz in hydrogen and deuterium. X-ray radiographs of materials of different thickness were obtained. Neutrons were detected using a system based upon 3He proportional counter in chare integrated mode. However, the reproducibility of this miniaturized device is low and several technological subjects have to be previously solved in order to produce neutrons for periods greater than minutes. Further studies in the Nanofocus are being carried out. In addition, a device with a stored energy of a few joules is being explored. A preliminary compact, low weight (3 kg), portable PF device (25 cm×5 cm×5 cm) for field applications has been designed. This device was designed to operate with few kilovolts (10 kV or less) with a stored energy of 2 J and a repetition rate of 10 Hz without cooling. A neutron flux of the order of 104-105 n/s is expected.

  17. AmBe Radiological Source Replacement Using Dense Plasma Focus Z-Pinch

    Science.gov (United States)

    Shaw, Brian; Povilus, Alexander; Chapman, Steven; Podpaly, Yuri; Cooper, Christopher; Higginson, Drew; Link, Anthony; Schmidt, Andrea

    2016-10-01

    A dense plasma focus (DPF) is a compact plasma gun that produces high energy ion beams up to several MeV through strong potential gradients formed from m=0 plasma instabilities. These ion beams can be used to replace radiological sources for a variety of applications. Americium-beryllium (AmBe) neutron sources are commonly used for oil well logging. An optimized DPF produces high energy helium ion beams of 2+ MeV which can interact with a beryllium target to produce neutrons. The alpha-Be interaction produces a neutron energy spectrum similar to the neutrons produced by the AmBe reaction. To demonstrate this concept experimentally a 2 kJ DPF is used to produce a beam of alpha particles which interacts with a beryllium target. We report on the improvements made to the DPF platform using He gas and the observation of 3.0 ×104 peak neutrons generated per shot. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  18. Development and experimental study of oil-free capacitor module for plasma focus device

    Science.gov (United States)

    Sharma, Ravindra Kumar; Sharma, Archana

    2017-03-01

    This development is concerned with the compact capacitor module for a plasma focus device. Oil-free, non-standard geometry capacitors are designed and developed for high current delivery in sub-microseconds time. Metalized dielectric film based pulse capacitor becomes progressively less viable at currents above 10 kA. It is due to reliability and energy scaling difficulties, based on effects such as vaporization, high resistivity, and end connection. Bipolar electrolytic capacitors are also not preferred due to their limited life and comparatively low peak current delivery. Bi-axially oriented polypropylene (BOPP) film with extended aluminum foil is a combination to deliver moderately high power. But, electrically weak points, relative permittivity, and the edge gap margins have made its adoption difficult. A concept has been developed in lab for implementing the above combination in a less complex and costly manner. This paper concerns the development and testing process techniques for quite different hollow cylindrical, oil-free capacitors (4 μ F , 10 kV, 20 nH). Shot life of 1000 has been experimentally performed on the test bed at its rated energy density level. The technological methods and engineering techniques are now available and utilized for manufacturing and testing of BOPP film based oil-free capacitors.

  19. Effect of driver impedance on dense plasma focus Z-pinch neutron yield

    Energy Technology Data Exchange (ETDEWEB)

    Sears, Jason, E-mail: sears8@llnl.gov, E-mail: schmidt36@llnl.gov; Link, Anthony, E-mail: sears8@llnl.gov, E-mail: schmidt36@llnl.gov; Schmidt, Andrea, E-mail: sears8@llnl.gov, E-mail: schmidt36@llnl.gov [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Welch, Dale [Voss Scientific, Albuquerque, NM 87108 (United States)

    2014-12-15

    The Z-pinch phase of a dense plasma focus (DPF) heats the plasma by rapid compression and accelerates ions across its intense electric fields, producing neutrons through both thermonuclear and beam-target fusion. Driver characteristics have empirically been shown to affect performance, as measured by neutron yield per unit of stored energy. We are exploring the effect of driver characteristics on DPF performance using particle-in-cell (PIC) simulations of a kJ scale DPF. In this work, our PIC simulations are fluid for the run-down phase and transition to fully kinetic for the pinch phase, capturing kinetic instabilities, anomalous resistivity, and beam formation during the pinch. The anode-cathode boundary is driven by a circuit model of the capacitive driver, including system inductance, the load of the railgap switches, the guard resistors, and the coaxial transmission line parameters. It is known that the driver impedance plays an important role in the neutron yield: first, it sets the peak current achieved at pinch time; and second, it affects how much current continues to flow through the pinch when the pinch inductance and resistance suddenly increase. Here we show from fully kinetic simulations how total neutron yield depends on the impedance of the driver and the distributed parameters of the transmission circuit. Direct comparisons between the experiment and simulations enhance our understanding of these plasmas and provide predictive design capability for neutron source applications.

  20. Ion probe beam experiments and kinetic modeling in a dense plasma focus Z-pinch

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, A., E-mail: schmidt36@llnl.gov; Ellsworth, J., E-mail: schmidt36@llnl.gov; Falabella, S., E-mail: schmidt36@llnl.gov; Link, A., E-mail: schmidt36@llnl.gov; McLean, H., E-mail: schmidt36@llnl.gov; Rusnak, B., E-mail: schmidt36@llnl.gov; Sears, J., E-mail: schmidt36@llnl.gov; Tang, V., E-mail: schmidt36@llnl.gov [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore CA 94550 (United States); Welch, D. [Voss Scientific, LLC, 418 Washington St SE, Albuquerque NM 87108 (United States)

    2014-12-15

    The Z-pinch phase of a dense plasma focus (DPF) emits multiple-MeV ions in a ∼cm length. The mechanisms through which these physically simple devices generate such high energy beams in a relatively short distance are not fully understood. We are exploring the origins of these large gradients using measurements of an ion probe beam injected into a DPF during the pinch phase and the first kinetic simulations of a DPF Z-pinch. To probe the accelerating fields in our table top experiment, we inject a 4 MeV deuteron beam along the z-axis and then sample the beam energy distribution after it passes through the pinch region. Using this technique, we have directly measured for the first time the acceleration of an injected ion beam. Our particle-in-cell simulations have been benchmarked on both a kJ-scale DPF and a MJ-scale DPF. They have reproduced experimentally measured neutron yields as well as ion beams and EM oscillations which fluid simulations do not exhibit. Direct comparisons between the experiment and simulations enhance our understanding of these plasmas and provide predictive design capability for accelerator and neutron source applications.

  1. Plasma focus neutron anisotropy measurements and influence of a deuteron beam obstacle

    Science.gov (United States)

    Talebitaher, A.; Springham, S. V.; Rawat, R. S.; Lee, P.

    2017-03-01

    The deuterium-deuterium (DD) fusion neutron yield and anisotropy were measured on a shot-to-shot basis for the NX2 plasma focus (PF) device using two beryllium fast-neutron activation detectors at 0° and 90° to the PF axis. Measurements were performed for deuterium gas pressures in the range 6-16 mbar, and positive correlations between neutron yield and anisotropy were observed at all pressures. Subsequently, at one deuterium gas pressure (13 mbar), the contribution to the fusion yield produced by the forwardly-directed D+ ion beam, emitted from the plasma pinch, was investigated by using a circular Pyrex plate to obstruct the beam and suppress its fusion contribution. Neutron measurements were performed with the obstacle positioned at two distances from the anode tip, and also without the obstacle. It was found that 80% of the neutron yield originates in the plasma pinch column and just above that. In addition, proton pinhole imaging was performed from the 0° and 90° directions to the pinch. The obtained proton images are consistent with the conclusion that DD fusion is concentrated ( 80%) in the pinch column region.

  2. High-Energy Ion Acceleration Mechanisms in a Dense Plasma Focus Z-Pinch

    Science.gov (United States)

    Higginson, D. P.; Link, A.; Schmidt, A.; Welch, D.

    2016-10-01

    The compression of a Z-pinch plasma, specifically in a dense plasma focus (DPF), is known to accelerate high-energy electrons, ions and, if using fusion-reactant ions (e.g. D, T), neutrons. The acceleration of particles is known to coincide with the peak constriction of the pinch, however, the exact physical mechanism responsible for the acceleration remains an area of debate and uncertainty. Recent work has suggested that this acceleration is linked to the growth of an m =0 (sausage) instability that evacuates a region of low-density, highly-magnetized plasma and creates a strong (>MV/cm) electric field. Using the fully kinetic particle-in-cell code LSP in 2D-3V, we simulate the compression of a 2 MA, 35 kV DPF plasma and investigate in detail the formation of the electric field. The electric field is found to be predominantly in the axial direction and driven via charge-separation effects related to the resistivity of the kinetic plasma. The strong electric and magnetic fields are shown to induce non-Maxwellian distributions in both the ions and electrons and lead to the acceleration of high-energy tails. We compare the results in the kinetic simulations to assumptions of magnetohydrodynamics (MHD). Prepared by LLNL under Contract DE-AC52-07NA27344.

  3. Seeding the m = 0 instability in dense plasma focus Z-pinches with a hollow anode

    CERN Document Server

    Liu, J X; McMahon, M; Tummel, K; Cooper, C; Higginson, D; Shaw, B; Povilus, A; Link, A; Schmidt, A

    2016-01-01

    The dense plasma focus (DPF) is a classic Z-pinch plasma device that has been studied for decades as a radiation source. The formation of the m = 0 plasma instability during the compression phase is linked to the generation of high-energy charged particle beams, which, when operated in deuterium, lead to beam-target fusion reactions and the generation of neutron yield. In this paper, we present a technique of seeding the m = 0 instability by employing a hollow in the anode. As the plasma sheath moves along the anode's hollow structure, a low density perturbation is formed and this creates a non-uniform plasma column which is highly unstable. Dynamics of the low density perturbation and preferential seeding of the m = 0 instability were studied in detail with fully kinetic plasma simulations performed in the Large Scale Plasma particle-in-cell code as well as with a simple snowplow model. The simulations showed that by employing an anode geometry with appropriate inner hollow radius, the neutron yield of the D...

  4. Fully Three-dimensional Simulation and Modeling of a Dense Plasma Focus

    CERN Document Server

    Meehan, B T

    2014-01-01

    A Dense Plasma Focus (DPF) is a pulsed-power machine that electromagnetically accelerates and cylindrically compresses a shocked plasma in a Z-pinch. The pinch results in a brief (about 100 nanosecond) pulse of X-rays, and, for some working gases, also a pulse of neutrons. A great deal of experimental research has been done into the physics of DPF reactions, and there exist mathematical models describing its behavior during the different time phases of the reaction. Two of the phases, known as the inverse pinch and the rundown, are approximately governed by magnetohydrodynamics, and there are a number of well-established codes for simulating these phases in two dimensions or in three dimensions under the assumption of axial symmetry. There has been little success, however, in developing fully three-dimensional simulations. In this work we present three-dimensional simulations of DPF reactions and demonstrate that 3D simulations predict qualitatively and quantitatively different behavior than their 2D counterp...

  5. Repetitive tabletop plasma focus to produce a tunable damage factor on materials for fusion reactors

    Science.gov (United States)

    Soto, Leopoldo; Pavez, Cristian; Inestrosa-Izurieta, Maria Jose; Moreno, Jose; Davis, Sergio; Bora, Biswajit; Avaria, Gonzalo; Jain, Jalaj; Altamirano, Luis; Panizo, Miguel; Gonzalez, Raquel; Rivera, Antonio

    2016-10-01

    Future thermonuclear reactors, both magnetic and inertial confinement approaches, need materials capable of withstanding the extreme radiation and heat loads expected from high repetition rate plasma. A damage factor (F = qτ1/2) in the order of 104 (W/cm2) s1/2 is expected. The axial plasma dynamics after the pinch in a tabletop plasma focus of hundred joules, PF-400J, was characterized by means of pulsed optical refractive diagnostics. The energy, interaction time and power flux of the plasma burst interacting with targets was obtained. Results show a high dependence of the damage factor with the distance from the anode top where the sample is located. A tunable damage factor in the range 10- 105(W/cm2) s1/2 can be obtained. At present the PF-400J operating at 0.077 Hz is being used to study the effects of fusion-relevant pulses on material target, including nanostructured materials. A new tabletop device to be operated up to 1Hz including tunable damage factor has been designed and is being constructed, thus thousand cumulative shots on materials could be obtained in few minutes. The scaling of the damage factor for plasma foci operating at different energies is discussed. Supported by CONICYT: PIA ACT-1115, PAI 79130026.

  6. Search for thermonuclear neutrons in a mega-ampere plasma focus

    Science.gov (United States)

    Klir, D.; Kubes, P.; Paduch, M.; Pisarczyk, T.; Chodukowski, T.; Scholz, M.; Kalinowska, Z.; Bienkowska, B.; Karpinski, L.; Kortanek, J.; Kravarik, J.; Rezac, K.; Ivanova-Stanik, I.; Tomaszewski, K.; Zielinska, E.

    2012-01-01

    Plasma focus experiments were carried out at a modified PF-1000 where the cathode disc was added in front of the anode. Experimental results indicated a fraction of thermonuclear neutrons on the mega-ampere current level. In order to prove the thermonuclear mechanism, the time of neutron production and the neutron energy spectrum were measured by time-of-flight (TOF) diagnostics. Neutron TOF signals showed that the neutron production was a multiphase process and more than one mechanism occurred simultaneously. The occurrence of the thermonuclear mechanism was most evident during the plasma stagnation at low deuterium pressures. At low filling pressures, the narrow width of the neutron energy spectra demonstrated an ion temperature of about 1 keV. The possibility of thermonuclear neutrons was studied also after the stagnation, during the main neutron emission. In this case, the thermonuclear mechanism could be verified by calculating the number of deuterons that participate in the fusion process. For the bulk of thermonuclear plasmas, a significant fraction of plasma should participate in fusion. Finally, the basic consideration of the thermonuclear mechanism in Z-pinches showed the reasonableness of the MagLIF concept.

  7. Investigation of structural properties of chromium thin films prepared by a plasma focus device

    Science.gov (United States)

    Javadi, S.; Habibi, M.; Ghoranneviss, M.; Lee, S.; Saw, S. H.; Behbahani, R. A.

    2012-08-01

    We report the synthesis of chromium thin films on Si(400) substrates by utilizing a low-energy (1.6 kJ) plasma focus device. The films of chromium are deposited with different numbers of focus shots (15, 25 and 35) at a distance of 8 cm and at 0° angular position with respect to the anode axis. The films are investigated structurally by x-ray diffraction analysis and morphologically by atomic force microscopy and scanning electron microscopy. The elemental composition is characterized by energy dispersive x-ray analysis. Furthermore, Vicker's micro hardness is used to study the mechanical properties of the deposited films. The degree of crystallinity of chromium films, the size of the particles and the hardness values of the films increase when the number of focus shots is raised from 15 to 25 and then decrease when the substrate is treated with 35 shots. We discuss the dynamic processes involved in the formation of the chromium films.

  8. Comparisons of dense-plasma-focus kinetic simulations with experimental measurements

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Link, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Welch, D. [Voss Scientific, Inc., Albuquerque, NM (United States); Ellsworth, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Falabella, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tang, V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-06-01

    Dense-plasma-focus (DPF) Z-pinch devices are sources of copious high-energy electrons and ions, x rays, and neutrons. The mechanisms through which these physically simple devices generate such high-energy beams in a relatively short distance are not fully understood and past optimization efforts of these devices have been largely empirical. Previously we reported on fully kinetic simulations of a DPF and compared them with hybrid and fluid simulations of the same device. Here we present detailed comparisons between fully kinetic simulations and experimental data on a 1.2 kJ DPF with two electrode geometries, including neutron yield and ion beam energy distributions. A more intensive third calculation is presented which examines the effects of a fully detailed pulsed power driver model. We also compare simulated electromagnetic fluctuations with direct measurement of radiofrequency electromagnetic fluctuations in a DPF plasma. These comparisons indicate that the fully kinetic model captures the essential physics of these plasmas with high fidelity, and provide further evidence that anomalous resistivity in the plasma arises due to a kinetic instability near the lower hybrid frequency.

  9. Low-Energy Plasma Focus as a Tailored X-Ray Source

    Science.gov (United States)

    Zakaullah, M.; Alamgir, K.; Shafiq, M.; Sharif, M.; Waheed, A.; Murtaza, G.

    2000-06-01

    A low-energy (2.3 kJ) plasma focus energized by a single 32-μF capacitor charged at 12 kV with filling gases hydrogen, neon, and argon is investigated as an X-ray source. Experiments are conducted with a copper and an aluminum anode. Specifically, attention is given to tailoring the radiation in different windows, e.g., 1.2-1.3 keV, 1.3-1.5 keV, 2.5-5 keV, and Cu-Kα line radiation. The highest X-ray emission is observed with neon filling and the copper anode in the 1.2-1.3 keV window, which we speculate to be generated due to recombination of hydrogenlike neon ions with a few eV to a few 10s of eV electrons. The wall-plug efficiency of the device is found to be 4%. The other significant emission occurs with hydrogen filling, which exhibits wall-plug efficiency of 1.7% for overall X-ray emission and 0.35% for Cu-Kα line radiation. The emission is dominated by the interaction of electrons in the current sheath with the anode tip. The emission with the aluminum anode and hydrogen filling is up to 10 J, which corresponds to wall-plug efficiency of 0.4%. The X-ray emission with argon filling is less significant.

  10. Fully three-dimensional simulation and modeling of a dense plasma focus

    Energy Technology Data Exchange (ETDEWEB)

    Meehan, B. T.; Niederhaus, J. H. J.

    2014-10-01

    A dense plasma focus (DPF) is a pulsed-power machine that electromagnetically accelerates and cylindrically compresses a shocked plasma in a Z-pinch. The pinch results in a brief (~ 100 ns) pulse of X-rays, and, for some working gases, also a pulse of neutrons. A great deal of experimental research has been done into the physics of DPF reactions, and there exist mathematical models describing its behavior during the different time phases of the reaction. Two of the phases, known as the inverse pinch and the rundown, are approximately governed by magnetohydrodynamics, and there are a number of well-established codes for simulating these phases in two dimensions or in three dimensions under the assumption of axial symmetry. There has been little success, however, in developing fully three-dimensional simulations. In this work we present three-dimensional simulations of DPF reactions and demonstrate that three-dimensional simulations predict qualitatively and quantitatively different behavior than their two-dimensional counterparts. One of the most important quantities to predict is the time duration between the formation of the gas shock and Z-pinch, and the three-dimensional simulations more faithfully represent experimental results for this time duration and are essential for accurate prediction of future experiments.

  11. Construction and experimental study of a 2.5 kJ, simply configured, Mather type plasma focus device

    Energy Technology Data Exchange (ETDEWEB)

    Shirani, B.; Abbasi, F. [Shahid Beheshti University, Tehran (Iran, Islamic Republic of). Radiation Application Department

    2010-06-15

    In this work, a 2.5 kJ plasma focus device (named as SBUPF1) has been constructed on the basis of a simple configuration. The most important characteristics of this configuration is relative simplicity and using less components in its structure compared with common configurations. SBUPF1 has been tested between 18- 25 kV and wide range of pressure for various gases including Argon, Neon and Deuterium. The system shows consistent and reproducible plasma focusing action as well as fusion neutron production (when deuterium is used as working gas). (author)

  12. Particle-in-cell modeling for MJ scale dense plasma focus with varied anode shape

    Energy Technology Data Exchange (ETDEWEB)

    Link, A., E-mail: link6@llnl.gov; Halvorson, C., E-mail: link6@llnl.gov; Schmidt, A. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Hagen, E. C. [National Security Technologies, Las Vegas, NV 89030 (United States); Rose, D. V.; Welch, D. R. [Voss Scientific LLC, Albuquerque NM 87108 (United States)

    2014-12-15

    Megajoule scale dense plasma focus (DPF) Z-pinches with deuterium gas fill are compact devices capable of producing 10{sup 12} neutrons per shot but past predictive models of large-scale DPF have not included kinetic effects such as ion beam formation or anomalous resistivity. We report on progress of developing a predictive DPF model by extending our 2D axisymmetric collisional kinetic particle-in-cell (PIC) simulations from the 4 kJ, 200 kA LLNL DPF to 1 MJ, 2 MA Gemini DPF using the PIC code LSP. These new simulations incorporate electrodes, an external pulsed-power driver circuit, and model the plasma from insulator lift-off through the pinch phase. To accommodate the vast range of relevant spatial and temporal scales involved in the Gemini DPF within the available computational resources, the simulations were performed using a new hybrid fluid-to-kinetic model. This new approach allows single simulations to begin in an electron/ion fluid mode from insulator lift-off through the 5-6 μs run-down of the 50+ cm anode, then transition to a fully kinetic PIC description during the run-in phase, when the current sheath is 2-3 mm from the central axis of the anode. Simulations are advanced through the final pinch phase using an adaptive variable time-step to capture the fs and sub-mm scales of the kinetic instabilities involved in the ion beam formation and neutron production. Validation assessments are being performed using a variety of different anode shapes, comparing against experimental measurements of neutron yield, neutron anisotropy and ion beam production.

  13. Interaction of powerful hot plasma and fast ion streams with materials in dense plasma focus devices

    Energy Technology Data Exchange (ETDEWEB)

    Chernyshova, M., E-mail: maryna.chernyshova@ipplm.pl [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Gribkov, V.A. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Institution of Russian Academy of Sciences A.A. Baikov Institute of Metallurgy and Material Science RAS, Moscow (Russian Federation); Kowalska-Strzeciwilk, E.; Kubkowska, M.; Miklaszewski, R.; Paduch, M.; Pisarczyk, T.; Zielinska, E. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Demina, E.V.; Pimenov, V.N.; Maslyaev, S.A. [Institution of Russian Academy of Sciences A.A. Baikov Institute of Metallurgy and Material Science RAS, Moscow (Russian Federation); Bondarenko, G.G. [National Research University Higher School of Economics (HSE), Moscow (Russian Federation); Vilemova, M.; Matejicek, J. [Institute of Plasma Physics of the CAS, Prague (Czech Republic)

    2016-12-15

    Highlights: • Materials perspective for use in mainstream nuclear fusion facilities were studied. • Powerful streams of hot plasma and fast ions were used to induce irradiation. • High temporal, spatial, angular and spectral resolution available in experiments. • Results of irradiation were investigated by number of analysis techniques. - Abstract: A process of irradiating and ablating solid-state targets with hot plasma and fast ion streams in two Dense Plasma Focus (DPF) devices – PF-6 and PF-1000 was examined by applying a number of diagnostics of nanosecond time resolution. Materials perspective for use in chambers of the mainstream nuclear fusion facilities (mainly with inertial plasma confinement like NIF and Z-machine), intended both for the first wall and for constructions, have been irradiated in these simulators. Optical microscopy, SEM, Atomic Emission Spectroscopy, images in secondary electrons and in characteristic X-ray luminescence of different elements, and X-ray elemental analysis, gave results on damageability for a number of materials including low-activated ferritic and austenitic stainless steels, β-alloy of Ti, as well as two types of W and a composite on its base. With an increase of the number of shots irradiating the surface, its morphology changes from weakly pronounced wave-like structures or ridges to strongly developed ones. At later stages, due to the action of the secondary plasma produced near the target materials they melted, yielding both blisters and a fracturing pattern: first along the grain and then “in-between” the grains creating an intergranular net of microcracks. At the highest values of power flux densities multiple bubbles appeared. Furthermore, in this last case the cracks were developed because of microstresses at the solidification of melt. Presence of deuterium within the irradiated ferritic steel surface nanolayers is explained by capture of deuterons in lattice defects of the types of impurity atoms

  14. Research on pinches driven by SPPED 2 generator hard X-ray and neutron emission in plasma focus configuration

    CERN Document Server

    Sánchez-Soto, L L; Silva, P; Sylvester, G S; Zambra, M; Pavez, C; Raspa, V; Castillo, F; Kies, W; Soto, Leopoldo; Moreno, Jose; Silva, Patricio; Sylvester, Gustavo; Zambra, Marcelo; Pavez, Cristian; Raspa, Veronica; Castillo, Fermin; Kies, Walter

    2004-01-01

    SPEED2 is a generator based on Marx technology and was designed in the University of Dusseldorf. SPEED2 consists on 40 +/- Marx modules connected in parallel (4.1 mF equivalent Marx generator capacity, 300 kV, 4 MA in short circuit, 187 kJ, 400 ns rise time, dI/dt~1013 A/s). Currently the SPEED2 is operating at the Comision Chilena de Energia Nuclear, CCHEN, Chile, being the most powerful and energetic device for dense transient plasma in the Southern Hemisphere. Most of the previous works developed in SPEED2 at Dusseldorf were done in a plasma focus configuration for soft X-ray emission and the neutron emission from SPEED2 was not completely studied. The research program at CCHEN considers experiments in different pinch configurations (plasma focus, gas puffed plasma focus, gas embedded Z-pinch, wire arrays) at current of hundred of kiloamperes to mega-amperes, using the SPEED2 generator. The Chilean operation has begun implementing and developing diagnostics in a conventional plasma focus configuration oper...

  15. Catalytic action of β source on x-ray emission from plasma focus

    Science.gov (United States)

    Ahmad, S.; Sadiq, Mehboob; Hussain, S.; Shafiq, M.; Zakaullah, M.; Waheed, A.

    2006-01-01

    The influence of preionization around the insulator sleeve by a mesh-type β source (Ni6328) for the x-ray emission from a (2.3-3.9 kJ) plasma focus device is investigated. Quantrad Si p-i-n diodes along with suitable filters are employed as time-resolved x-ray detectors and a multipinhole camera with absorption filters is used for time-integrated analysis. X-ray emission in 4π geometry is measured as a function of argon and hydrogen gas filling pressures with and without β source at different charging voltages. It is found that the pressure range for the x-ray emission is broadened, x-ray emission is enhanced, and shot to shot reproducibility is improved with the β source. With argon, the CuKα emission is estimated to be 27.14 J with an efficiency of 0.7% for β source and 21.5 J with an efficiency of 0.55% without β source. The maximum x-ray yield in 4π geometry is found to be about 68.90 J with an efficiency of 1.8% for β source and 54.58 J with an efficiency of 1.4% without β source. With hydrogen, CuKα emission is 11.82 J with an efficiency of 0.32% for β source and 10.07 J with an efficiency of 0.27% without β source. The maximum x-ray yield in 4π geometry is found to be 30.20 J with an efficiency of 0.77% for β source and 25.58 J with an efficiency of 0.6% without β source. The x-ray emission with Pb insert at the anode tip without β source is also investigated and found to be reproducible and significantly high. The maximum x-ray yield is estimated to be 46.6 J in 4π geometry with an efficiency of 1.4% at 23 kV charging voltage. However, degradation of x-ray yield is observed when charging voltage exceeds 23 kV for Pb insert. From pinhole images it is observed that the x-ray emission due to the bombardment of electrons at the anode tip is dominant in both with and without β source.

  16. Using FLUKA to Study Concrete Square Shield Performance in Attenuation of Neutron Radiation Produced by APF Plasma Focus Neutron Source

    Science.gov (United States)

    Nemati, M. J.; Habibi, M.; Amrollahi, R.

    2013-04-01

    In 2010, representatives from the Nuclear Engineering and physics Department of Amirkabir University of Technology (AUT) requested development of a project with the objective of determining the performance of a concrete shield for their Plasma Focus as neutron source. The project team in Laboratory of Nuclear Engineering and physics department of Amirkabir University of Technology choose some shape of shield to study on their performance with Monte Carlo code. In the present work, the capability of Monte Carlo code FLUKA will be explored to model the APF Plasma Focus, and investigating the neutron fluence on the square concrete shield in each region of problem. The physical models embedded in FLUKA are mentioned, as well as examples of benchmarking against future experimental data. As a result of this study suitable thickness of concrete for shielding APF will be considered.

  17. FePt nanoparticle formation with lower phase transition temperature by single shot plasma focus ion irradiation

    Science.gov (United States)

    Lin, J. J.; Roshan, M. V.; Pan, Z. Y.; Verma, R.; Lee, P.; Springham, S. V.; Tan, T. L.; Rawat, R. S.

    2008-07-01

    Uniform FePt nanoparticles were synthesized through nanostructuring of pulsed laser deposited FePt thin films by single shot H+ ion irradiation using a plasma focus device. The annealing temperature required for phase transition from low Ku face-centred cubic to high Ku face-centred tetragonal, for ion irradiated samples, is simultaneously lowered down to 400 °C. The energetic H+ ion irradiation significantly reduces the activation energy for atomic ordering by increasing the number of vacancies. The advantage of using a plasma focus device is that it can achieve nanostructuring in much shorter time, in single shot ion exposure with pulse duration of typically about a few hundreds of nanoseconds, as compared with much longer duration required by continuous ion sources.

  18. Study of Magnetic Field Behavior at Lower Pressure of Neon in the Axial Phase of INTI Plasma Focus

    Directory of Open Access Journals (Sweden)

    K.K.A. Devi

    2014-03-01

    Full Text Available The magnetic field distribution substantially affects mechanisms for the generation of radiation in Z-pinches. Investigation of the axial component of the magnetic field is one of the important problems in plasma focus studies. The designed magnetic probe is intended to use for the study of current sheet in INTI plasma focus device with energy of about 3.3 kJ. The measurements of the azimuthal component of the magnetic field on the INTI Plasma Focus operated at neon pressures below 1 Torr was carried out using a custom built calibrated magnetic probe. The probe was tested for neon gas under the various lower pressures (i.e., 0.1, 0.3, 0.5 and 0.7, 1, 2, 3, 5 torr etc.. It is observed that the time response of the designed probe is sufficient for the rise time of the magnetic field associated with the current in the axial phase. We also note that the small size of the designed probe is well suited to sense the magnetic field without perturbing the plasma unduly. The probe designed and constructed is also suitable to carryout measurements to obtain axial distributions of trajectory, average axial velocity and magnetic field of the current sheath at a certain radial distances along the axis of the tube.

  19. OPTIMISATION OF NEON SXR (SOFT X-RAY YIELD OF THE INTI PLASMA FOCUS MACHINE AT 12 kV

    Directory of Open Access Journals (Sweden)

    A.R.J.A. FEDERICO

    2015-02-01

    Full Text Available The INTI plasma focus machine is a 3 kJ Mather type plasma focus machine,powered by a single Maxwell capacitor. The system produces remarkable consistent focusing action in neon, making it a suitable source for the production of high energy photons, electrons, ions and neon soft x-rays (SXR [1, 2]. The aim of this paper is to optimise the neon SXR yield of the INTI plasma focus machine operated at 12 kV by parametrically, changing the anode dimensions (radius and length using the Lee Model Code (version RADPFV5.15dd. Results of the optimisation procedures resulted in a neon SXR yield of 6.47 J at 2.5 torr and 12 kV, with a shorter length and a fatter anode radius of 7.9 cm and 1.2 cm respectively. This gives an improvement in the neon SXR yield of 40% when compares to neon SXR yield of 2.74 J at 2.5 torr 12 kV with the present configurations.

  20. Surface modifications of fusion reactor relevant materials on exposure to fusion grade plasma in plasma focus device

    Energy Technology Data Exchange (ETDEWEB)

    Niranjan, Ram, E-mail: niranjan@barc.gov.in [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Rout, R.K.; Srivastava, R. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Chakravarthy, Y. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Mishra, P. [Materials Processing Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kaushik, T.C.; Gupta, Satish C. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2015-11-15

    Graphical abstract: - Highlights: • Exposure of materials (W, Ni, SS, Mo and Cu) to fusion plasma in a plasma focus device. • The erosion and the formations of blisters, pores, craters, micro-cracks after irradiation. • The structural phase transformation in the SS sample after irradiation. • The surface layer alloying of the samples with the plasma focus anode material. - Abstract: An 11.5 kJ plasma focus (PF) device was used here to irradiate materials with fusion grade plasma. The surface modifications of different materials (W, Ni, stainless steel, Mo and Cu) were investigated using various available techniques. The prominent features observed through the scanning electron microscope on the sample surfaces were erosions, cracks, blisters and craters after irradiations. The surface roughness of the samples increased multifold after exposure as measured by the surface profilometer. The X-ray diffraction analysis indicated the changes in the microstructures and the structural phase transformation in surface layers of the samples. We observed change in volumes of austenite and ferrite phases in the stainless steel sample. The energy dispersive X-ray spectroscopic analysis suggested alloying of the surface layer of the samples with elements of the PF anode. We report here the comparative analysis of the surface damages of materials with different physical, thermal and mechanical properties. The investigations will be useful to understand the behavior of the perspective materials for future fusion reactors (either in pure form or in alloy) over the long operations.

  1. Experimental study of soft X-ray intensity with different anode tips in Amirkabir plasma focus device

    Indian Academy of Sciences (India)

    HABIBI MORTEZA; MAHTAB MAHSA

    2016-07-01

    To study the effect of different anode tip geometries on the intensity of soft X-rays emitted from a 4 kJ plasma focus device (PFD), we considered five different anode tips which were cylindrical-flat, cylindricalhollow, spherical-convex, cone-flat and cone-hollow tips. BPX-65 PIN diodes covered by four different filters are used to register the intensity of soft X-rays. The use of cone-flat anode tip has augmented the emitted X-ray three times compared to the conventional cylindrical-flat anode.

  2. Dense plasma focus PACO as a hard X-ray emitter: a study on the radiation source

    OpenAIRE

    Supán, L.; Guichón, S.; Milanese, Maria Magdalena; Niedbalski, Jorge Julio; Moroso, Roberto Luis; Acuña, H.; Malamud, Florencia

    2016-01-01

    The radiation in the X-ray range detected outside the vacuum chamber of the dense plasma focus (DPF) PACO, are produced on the anode zone. The zone of emission is studied in a shot-to-shot analysis, using pure deuterium as filling gas. We present a diagnostic method to determine the place and size of the hard X-ray source by image analysis of high density radiography plates. Fil: Supán, L.. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Insti...

  3. ESTIMATING RATIO OF PEAK TO UNIFORM VALUES OF VARIOUS PROFILES OF RELEVANCE TO PLASMA FOCUS PINCH COLUMNS

    Directory of Open Access Journals (Sweden)

    CHONG PERK LIN

    2013-02-01

    Full Text Available In the Lee Model code for radiative plasma focus computation, both the density profile and the temperature profile (versus anode radius of the pinch column are approximated by step functions with uniform values across the column radius. This means that the computed density and temperatures will be lower than the physical situation where the density and temperature profiles will certainly have peak values higher than the uniform (with radius values of the step function. It has been shown that the density profile is side-peaked (somewhat shell-shaped or like the shape of a volcanic crater with the assumption of no reflected shock wave; whereas the temperature profile is centre-peaked somewhat like a Gaussian shape. The aim of this paper is to investigate the use of higher degree mathematical function, where the crater-shaped profile can be well represented, to pproximate the plasma focus density profile. Two different approximated functions will be discussed: namely Gaussian distribution function and Bézier function. From these profiles we obtain the likely ratio of the profiled peak temperature to the step function uniform temperature and the peak density to the step function uniform density. In this manner we are able to suggest correction factors to the temperature and density computed by the Lee Model code.

  4. The Effect of Driver Rise-Time on Pinch Current and its Impact on Plasma Focus Performance and Neutron Yield

    Science.gov (United States)

    Sears, Jason; Schmidt, Andrea; Link, Anthony; Welch, Dale

    2016-10-01

    Experiments have suggested that dense plasma focus (DPF) neutron yield increases with faster drivers [Decker NIMP 1986]. Using the particle-in-cell code LSP [Schmidt PRL 2012], we reproduce this trend in a kJ DPF [Ellsworth 2014], and demonstrate how driver rise time is coupled to neutron output. We implement a 2-D model of the plasma focus including self-consistent circuit-driven boundary conditions. Driver capacitance and voltage are varied to modify the current rise time, and anode length is adjusted so that run-in coincides with the peak current. We observe during run down that magnetohydrodynamic (MHD) instabilities of the sheath shed blobs of plasma that remain in the inter-electrode gap during run in. This trailing plasma later acts as a low-inductance restrike path that shunts current from the pinch during maximum compression. While the MHD growth rate increases slightly with driver speed, the shorter anode of the fast driver allows fewer e-foldings and hence reduces the trailing mass between electrodes. As a result, the fast driver postpones parasitic restrikes and maintains peak current through the pinch during maximum compression. The fast driver pinch therefore achieves best simultaneity between its ion beam and peak target density, which maximizes neutron production. Prepared by LLNL under Contract DE-AC52-07NA27344.

  5. Pancreatitis - discharge

    Science.gov (United States)

    Chronic pancreatitis - discharge; Pancreatitis - chronic - discharge; Pancreatic insufficiency - discharge; Acute pancreatitis - discharge ... You were in the hospital because you have pancreatitis. This is a swelling of the pancreas. You ...

  6. Re-appraisal and extension of the Gratton-Vargas two-dimensional analytical snowplow model of plasma focus evolution in the context of contemporary research

    CERN Document Server

    Auluck, S K H

    2013-01-01

    Recent resurgence of interest in applications of dense plasma focus and doubts about the conventional view of dense plasma focus as a purely irrotational compressive flow have re-opened questions concerning device optimization. In this context, this paper re-appraises and extends the analytical snowplow model of plasma focus sheath evolution developed by F. Gratton and J.M. Vargas (GV) (Energy Storage, Compression and Switching, Ed. V. Nardi, H. Sahlin, and W. H. Bostick, Eds., vol. 2. New York: Plenum, 1983, p. 353) and shows its relevance to contemporary research. The GV model enables construction of a special orthogonal coordinate system in which the plasma flow problem can be simplified and a model of sheath structure can be formulated. The LPP plasma focus facility, which reports neutron yield better than global scaling law, is shown to be operating closer to an optimum operating point of the GV model as compared with PF-1000.

  7. Stereotactic radiosurgery - discharge

    Science.gov (United States)

    Gamma knife - discharge; Cyberknife - discharge; Stereotactic radiotherapy - discharge; Fractionated stereotactic radiotherapy - discharge; Cyclotrons - discharge; Linear accelerator - discharge; Lineacs - ...

  8. Re-appraisal and extension of the Gratton-Vargas two-dimensional analytical snowplow model of plasma focus. II. Looking at the singularity

    Energy Technology Data Exchange (ETDEWEB)

    Auluck, S. K. H., E-mail: skhauluck@gmail.com [HiQ TechKnowWorks Private Limited, Nerul, Navi Mumbai 400706 (India)

    2015-11-15

    The Gratton-Vargas snowplow model, recently revisited and expanded [S. K. H. Auluck, Phys. Plasmas 20, 112501 (2013)], has given rise to significant new insights into some aspects of the Dense Plasma Focus (DPF), in spite of being a purely kinematic description having no reference to plasma phenomena. It is able to provide a good fit to the experimental current waveforms in at least 4 large facilities. It has been used for construction of a local curvilinear frame of reference, in which conservation laws for mass, momentum, and energy can be reduced to effectively-one-dimensional hyperbolic conservation law equations. Its utility in global parameter optimization of device parameters has been demonstrated. These features suggest that the Gratton-Vargas model deserves a closer look at its supposed limitations near the singular phase of the DPF. This paper presents a discussion of its development near the device axis, based on the original work of Gratton and Vargas, with some differences. It is shown that the Gratton-Vargas partial differential equation has solutions for times after the current singularity, which exhibit an expanding bounded volume (which can serve as model of an expanding plasma column) and decreasing dynamic inductance of the discharge, in spite of having no built-in hydrodynamics. This enables the model to qualitatively reproduce the characteristic shape of the current derivative in DPF experiments without reference to any plasma phenomena, such as instabilities, anomalous resistance, or reflection of hydrodynamic shock wave from the axis. The axial propagation of the solution exhibits a power-law dependence on the dimensionless time starting from the time of singularity, which is similar to the power-law relations predicted by theory of point explosions in ideal gases and which has also been observed experimentally.

  9. Re-appraisal and extension of the Gratton-Vargas two-dimensional analytical snowplow model of plasma focus. II. Looking at the singularity

    Science.gov (United States)

    Auluck, S. K. H.

    2015-11-01

    The Gratton-Vargas snowplow model, recently revisited and expanded [S. K. H. Auluck, Phys. Plasmas 20, 112501 (2013)], has given rise to significant new insights into some aspects of the Dense Plasma Focus (DPF), in spite of being a purely kinematic description having no reference to plasma phenomena. It is able to provide a good fit to the experimental current waveforms in at least 4 large facilities. It has been used for construction of a local curvilinear frame of reference, in which conservation laws for mass, momentum, and energy can be reduced to effectively-one-dimensional hyperbolic conservation law equations. Its utility in global parameter optimization of device parameters has been demonstrated. These features suggest that the Gratton-Vargas model deserves a closer look at its supposed limitations near the singular phase of the DPF. This paper presents a discussion of its development near the device axis, based on the original work of Gratton and Vargas, with some differences. It is shown that the Gratton-Vargas partial differential equation has solutions for times after the current singularity, which exhibit an expanding bounded volume (which can serve as model of an expanding plasma column) and decreasing dynamic inductance of the discharge, in spite of having no built-in hydrodynamics. This enables the model to qualitatively reproduce the characteristic shape of the current derivative in DPF experiments without reference to any plasma phenomena, such as instabilities, anomalous resistance, or reflection of hydrodynamic shock wave from the axis. The axial propagation of the solution exhibits a power-law dependence on the dimensionless time starting from the time of singularity, which is similar to the power-law relations predicted by theory of point explosions in ideal gases and which has also been observed experimentally.

  10. Bounds imposed on the sheath velocity of a dense plasma focus by conservation laws and ionization stability condition

    CERN Document Server

    Auluck, S K H

    2014-01-01

    Experimental data compiled over five decades of dense plasma focus research is consistent with the snowplow model of sheath propagation, based on the hypothetical balance between magnetic pressure driving the plasma into neutral gas ahead and wind pressure resisting its motion. The resulting sheath velocity, or the numerically proportional drive parameter, is known to be approximately constant for devices optimized for neutron production over 8 decades of capacitor bank energy. This paper shows that the validity of the snowplow hypothesis, with some correction, as well as the non-dependence of sheath velocity on device parameters, have their roots in local conservation laws for mass, momentum and energy coupled with the ionization stability condition. Both upper and lower bounds on sheath velocity are shown to be related to material constants of the working gas and independent of the device geometry and capacitor bank impedance.

  11. Design and initial results from a kilojoule level dense plasma focus with hollow anode and cylindrically symmetric gas puff

    Science.gov (United States)

    Ellsworth, J. L.; Falabella, S.; Tang, V.; Schmidt, A.; Guethlein, G.; Hawkins, S.; Rusnak, B.

    2014-01-01

    We have designed and built a Dense Plasma Focus (DPF) Z-pinch device using a kJ-level capacitor bank and a hollow anode, and fueled by a cylindrically symmetric gas puff. Using this device, we have measured peak deuteron beam energies of up to 400 keV at 0.8 kJ capacitor bank energy and pinch lengths of ˜6 mm, indicating accelerating fields greater than 50 MV/m. Neutron yields of on the order of 107 per shot were measured during deuterium operation. The cylindrical gas puff system permitted simultaneous operation of DPF with a radiofrequency quadrupole accelerator for beam-into-plasma experiments. This paper describes the machine design, the diagnostic systems, and our first results.

  12. Bounds imposed on the sheath velocity of a dense plasma focus by conservation laws and ionization stability condition

    Science.gov (United States)

    Auluck, S. K. H.

    2014-09-01

    Experimental data compiled over five decades of dense plasma focus research are consistent with the snowplow model of sheath propagation, based on the hypothetical balance between magnetic pressure driving the plasma into neutral gas ahead and "wind pressure" resisting its motion. The resulting sheath velocity, or the numerically proportional "drive parameter," is known to be approximately constant for devices optimized for neutron production over 8 decades of capacitor bank energy. This paper shows that the validity of the snowplow hypothesis, with some correction, as well as the non-dependence of sheath velocity on device parameters, have their roots in local conservation laws for mass, momentum, and energy coupled with the ionization stability condition. Both upper and lower bounds on sheath velocity are shown to be related to material constants of the working gas and independent of the device geometry and capacitor bank impedance.

  13. Specific features of X-ray generation by plasma focus chambers with deuterium and deuterium-tritium fillings

    Science.gov (United States)

    Dulatov, A. K.; Krapiva, P. S.; Lemeshko, B. D.; Mikhailov, Yu. V.; Moskalenko, I. N.; Prokuratov, I. A.; Selifanov, A. N.

    2016-01-01

    The process of hard X-ray (HXR) generation in plasma focus (PF) chambers was studied experimentally. The radiation was recorded using scintillation detectors with a high time resolution and thermoluminescent detectors in combination with the method of absorbing filters. Time-resolved analysis of the processes of neutron and X-ray generation in PFs is performed. The spectra of HXR emission from PF chambers with deuterium and deuterium-tritium fillings are determined. In experiments with PF chambers filled with a deuterium-tritium mixture, in addition to the HXR pulse with photon energies of up to 200-300 keV, a γ-ray pulse with photon energies of up to 2.5-3.0 MeV is recorded, and a mechanism of its generation is proposed.

  14. Dense Plasma Focus Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hui [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Li, Shengtai [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jungman, Gerard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hayes-Sterbenz, Anna Catherine [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-07-10

    Here we report on high-fidelity 2D and 3D numerical magnetohydrodynamic (MHD) simulations using the LA-COMPASS code to study the pinch formation dynamics in a DPF and the associated instabilities and neutron production.

  15. Characterization of the axial plasma shock in a table top plasma focus after the pinch and its possible application to testing materials for fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Soto, Leopoldo, E-mail: lsoto@cchen.cl; Pavez, Cristian; Moreno, José [Comisión Chilena de Energía Nuclear, Casilla 188-D, Santiago (Chile); Centro de Investigación y Aplicaciones en Física de Plasmas y Potencia Pulsada, P" 4, Santiago-Talca (Chile); Departamento de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andrés Bello, República 220, Santiago (Chile); Inestrosa-Izurieta, María José [Comisión Chilena de Energía Nuclear, Casilla 188-D, Santiago (Chile); Centro de Investigación y Aplicaciones en Física de Plasmas y Potencia Pulsada, P" 4, Santiago-Talca (Chile); Veloso, Felipe [Instituto de Física, Pontificia Universidad Católica de Chile, Santiago (Chile); Gutiérrez, Gonzalo [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Santiago (Chile); Vergara, Julio [Facultad de Ingeniería, Pontificia Universidad Católica de Chile, Santiago (Chile); Clausse, Alejandro [CNEA-CONICET and Universidad Nacional del Centro, 7000 Tandil (Argentina); Bruzzone, Horacio [CONICET and Universidad de Mar del Plata, Mar del Plata (Argentina); Castillo, Fermín [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos (Mexico); and others

    2014-12-15

    The characterization of plasma bursts produced after the pinch phase in a plasma focus of hundreds of joules, using pulsed optical refractive techniques, is presented. A pulsed Nd-YAG laser at 532 nm and 8 ns FWHM pulse duration was used to obtain Schlieren images at different times of the plasma dynamics. The energy, interaction time with a target, and power flux of the plasma burst were assessed, providing useful information for the application of plasma focus devices for studying the effects of fusion-relevant pulses on material targets. In particular, it was found that damage factors on targets of the order of 10{sup 4} (W/cm{sup 2})s{sup 1/2} can be obtained with a small plasma focus operating at hundred joules.

  16. Global parameter optimization of Mather type plasma focus in the framework of the Gratton-Vargas two-dimensional snowplow model

    CERN Document Server

    Auluck, S K H

    2014-01-01

    Dense Plasma Focus (DPF) is known to produce highly energetic ions, electrons and plasma environment which can be used for breeding of short-lived isotopes, plasma nanotechnology and other material processing applications. Commercial utilization of DPF in such areas would need a design tool which can be deployed in an automatic search for the best possible device configuration for a given application. The recently revisited [S K H Auluck, Physics of Plasmas 20, 112501 (2013)] Gratton-Vargas (GV) two-dimensional analytical snowplow model of plasma focus provides a numerical formula for dynamic inductance of a Mather type plasma focus fitted to thousands of automated computations, which enables construction of such design tool. This inductance formula is utilized in the present work to explore global optimization, based on first-principles optimality criteria, in a 4-dimensional parameter-subspace of the zero-resistance GV model. The optimization process is shown to reproduce the empirically observed constancy ...

  17. Diagnostic systems for the nuclear fusion and plasma research in the PF-24 plasma focus laboratory at the IFJ PAN

    Directory of Open Access Journals (Sweden)

    Marciniak Łukasz

    2016-12-01

    Full Text Available This paper presents a set of diagnostics dedicated to PF-24 - new medium size - plasma focus (PF device built and operated at the Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN. The PF-24 can operate at energy level up to 93 kJ and charging voltage up to 40 kV. Each condenser is connected with a specially designed spark gap with a very small jitter, which ensures a high effi ciency and a low current rise time. The working parameters of PF-24 generator make it a suitable tool for testing new detection systems to be used in fusion research. Four types of such detection systems are presented in this article: three diagnostic systems used to measure electric quantities (Rogowski coil, magnetic probe, capacitance probe, neutron counter based on beryllium activation, fast neutron pinhole camera based on small-area BCF-12 plastic scintillation detectors and high-speed four-frame soft X-ray camera with microchannel plate.

  18. The effect of anode shape on neon soft x-ray emissions and current sheath configuration in plasma focus device

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, M A; Sobhanian, S [Faculty of Physics, University of Tabriz, Tabriz (Iran, Islamic Republic of); Wong, C S [Plasma Research Laboratory, Physics Department, University of Malaya, Kuala Lumpur (Malaysia); Lee, S; Lee, P; Rawat, R S, E-mail: rajdeep.rawat@nie.edu.s [Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University (Singapore)

    2009-02-21

    The effect of three different anode shapes, flat, tapered and hemispherical, on the x-ray emission characteristics of a neon filled UNU-ICTP plasma focus device is investigated. The current sheath dynamics, in the radial collapse phase, has been simultaneously interrogated using the laser shadowgraphy method to understand the variation in x-ray emission characteristics for anodes of different shapes used in the experiments. The maximum neon soft x-ray (SXR) yield for the flat anode is about 7.5 {+-} 0.4 J at 4 mbar, whereas for hemispherical and tapered anodes the neon SXR is almost halved with the optimum pressure shifting to a lower value of 3 mbar. The laser shadowgraphic images confirm that the reduction in the overall neon SXR yield is due to the reduced focused plasma column length for these anodes. The relative HXR yield was the highest for the hemispherical anode followed by the tapered and the flat anodes in that order. The shadowgraphic images and the voltage probe signals confirmed that for the hemispherical anode the multiple-pinch phenomenon was most commonly observed, which could be responsible for multiple HXR bursts for this anode with maximum HXR yields.

  19. Deposition of magnesium nitride thin films on stainless steel-304 substrates by using a plasma focus device

    Science.gov (United States)

    Ramezani, Amir Hoshang; Habibi, Maryam; Ghoranneviss, Mahmood

    2014-08-01

    In this research, for the first time, we synthesize magnesium nitride thin films on 304-type stainless steel substrates using a Mather-type (2 kJ) plasma focus (PF) device. The films of magnesium nitride are coated with different number of focus shots (like 15, 25 and 35) at a distance of 8 cm from the anode tip and at 0° angular position with respect to the anode axis. For investigation of the structural properties and surface morphology of magnesium nitride films, we utilized the X-ray diffractometer (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM) analysis, respectively. Also, the elemental composition is characterized by energy-dispersive X-ray (EDX) analysis. Furthermore, Vicker's microhardness is used to study the mechanical properties of the deposited films. The results show that the degree of crystallinity of deposited thin films (from XRD), the average size of particles and surface roughness (from AFM), crystalline growth of structures (from SEM) and the hardness values of the films depend on the number of focus shots. The EDX analysis demonstrates the existence of the elemental composition of magnesium in the deposited samples.

  20. Deposition of Chromium Thin Films on Stainless Steel-304 Substrates Using a Low Energy Plasma Focus Device

    Science.gov (United States)

    Javadi, S.; Ghoranneviss, M.; Hojabri, A.; Habibi, M.; Hosseinnejad, M. T.

    2012-06-01

    In this paper, we study thin films of chromium deposited on stainless steel-304 substrates using a low energy (1.6 kJ) plasma focus device. The films of chromium are likewise deposited with 25 focus shots each at various axial distances from the top of the anode (3, 5, 7, 9 and 11 cm). We also consider different angular positions with respect to the anode axis (0°, 15° and 30°) at a distance of 5 cm from the anode tip to deposit the chromium films on the stainless steel substrates. To characterize the structural properties of the films, we benefit from X-ray diffraction (XRD) analysis. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) are applied as well to study the surface morphology of these deposited films. Furthermore, we make use of Vicker's micro-hardness measurements to investigate the mechanical properties of chromium thin films. The XRD results show that the degree of crystallinity of chromium thin films depends on the substrate axial and angular positions. The AFM images illustrate that the film deposited at the distance of 5 cm and the angular position of 0° has quite a uniform surface with homogeneous distribution of grains on the film surface. From the hardness results, we observe that the sample deposited at the axial distance of 5 cm from the anode tip and at the angle of 0° with respect to the anode axis, is harder than the other deposited films.

  1. Effect of deposition parameters on structural and mechanical properties of niobium nitride synthesized by plasma focus device

    Science.gov (United States)

    Siddiqui, Jamil; Hussain, Tousif; Ahmad, Riaz; Khalid, Nida

    2015-06-01

    Effects of deposition angle and axial distance on the structural and mechanical properties of niobium nitride synthesized by a dense plasma focus (DPF) system are studied. The x-ray diffraction (XRD) confirms that the deposition parameters affect the growth of multi-phase niobium nitride. Scanning electron microscopy (SEM) shows the granular surface morphology with strong thermally assisted coagulation effects observed at the 5-cm axial distance. The non-porous granular morphology observed at the 9-cm distance along the anode axis is different from those observed at deposition angles of 10° and 20°. Energy dispersive x-ray (EDX) spectroscopy reveals the maximum nitrogen content at the shortest (5 cm) axial position. Atomic force microscopy (AFM) exhibits that the roughness of coated films varies for coatings synthesized at different axial and angular positions, and the Vickers micro-hardness test shows that a maximum hardness value is (08.44 ± 0.01) GPa for niobium nitride synthesized at 5-cm axial distance, which is about 500% more than that of a virgin sample. Project supported by the HEC, Pakistan.

  2. EBT2 Dosimetry of X-rays produced by the electron beam from PFMA-3, a Plasma Focus for medical applications

    CERN Document Server

    Ceccolini, Elisa; Mostacci, Domiziano; Sumini, Marco; Tartari, Agostino

    2011-01-01

    The electron beam emitted from the back of Plasma Focus devices is being studied as a radiation source for IORT (IntraOperative Radiation Therapy) applications. A Plasma Focus device is being developed to this aim, to be utilized as an X-ray source. The electron beam is driven to impinge on 50 {\\mu}m brass foil, where conversion X-rays are generated. Measurements with gafchromic film are performed to analyse the attenuation of the X-rays beam and to predict the dose given to the culture cell in radiobiological experiments to follow.

  3. Observed Multi-Decade DD and DT Z-Pinch Fusion Rate Scaling in 5 Dense Plasma Focus Fusion Machines

    Energy Technology Data Exchange (ETDEWEB)

    Hagen, E. C. [National Security Technologies, LLC; Lowe, D. R. [National Security Technologies, LLC; O' Brien, R. [University of Nevada, Las Vegas; Meehan, B. T. [National Security Technologies, LLC

    2013-06-18

    Dense Plasma Focus (DPF) machines are in use worldwide or a wide variety of applications; one of these is to produce intense, short bursts of fusion via r-Z pinch heating and compression of a working gas. We have designed and constructed a series of these, ranging from portable to a maximum energy storage capacity of 2 MJ. Fusion rates from 5 DPF pulsed fusion generators have been measured in a single laboratory using calibrated activation detectors. Measured rates range from ~ 1015 to more than 1019 fusions per second have been measured. Fusion rates from the intense short (20 – 50 ns) periods of production were inferred from measurement of neutron production using both calibrated activation detectors and scintillator-PMT neutron time of flight (NTOF) detectors. The NTOF detectors are arranged to measure neutrons versus time over flight paths of 30 Meters. Fusion rate scaling versus energy and current will be discussed. Data showing observed fusion cutoff at D-D fusion yield levels of approximately 1*1012, and corresponding tube currents of ~ 3 MA will be shown. Energy asymmetry of product neutrons will also be discussed. Data from the NTOF lines of sight have been used to measure energy asymmetries of the fusion neutrons. From this, center of mass energies for the D(d,n)3He reaction are inferred. A novel re-entrant chamber that allows extremely high single pulse neutron doses (> 109 neutrons/cm2 in 50 ns) to be supplied to samples will be described. Machine characteristics and detector types will be discussed.

  4. Global parameter optimization of a Mather-type plasma focus in the framework of the Gratton-Vargas two-dimensional snowplow model

    Science.gov (United States)

    Auluck, S. K. H.

    2014-12-01

    Dense plasma focus (DPF) is known to produce highly energetic ions, electrons and plasma environment which can be used for breeding short-lived isotopes, plasma nanotechnology and other material processing applications. Commercial utilization of DPF in such areas would need a design tool that can be deployed in an automatic search for the best possible device configuration for a given application. The recently revisited (Auluck 2013 Phys. Plasmas 20 112501) Gratton-Vargas (GV) two-dimensional analytical snowplow model of plasma focus provides a numerical formula for dynamic inductance of a Mather-type plasma focus fitted to thousands of automated computations, which enables the construction of such a design tool. This inductance formula is utilized in the present work to explore global optimization, based on first-principles optimality criteria, in a four-dimensional parameter-subspace of the zero-resistance GV model. The optimization process is shown to reproduce the empirically observed constancy of the drive parameter over eight decades in capacitor bank energy. The optimized geometry of plasma focus normalized to the anode radius is shown to be independent of voltage, while the optimized anode radius is shown to be related to capacitor bank inductance.

  5. Bronchiolitis - discharge

    Science.gov (United States)

    RSV bronchiolitis - discharge; Respiratory syncytial virus bronchiolitis - discharge ... Your child has bronchiolitis , which causes swelling and mucus to build up in the smallest air passages of the lungs. In the hospital, ...

  6. Experimental results on the irradiation of nuclear fusion relevant materials at the dense plasma focus ‘Bora’ device

    Science.gov (United States)

    Cicuttin, A.; Crespo, M. L.; Gribkov, V. A.; Niemela, J.; Tuniz, C.; Zanolli, C.; Chernyshova, M.; Demina, E. V.; Latyshev, S. V.; Pimenov, V. N.; Talab, A. A.

    2015-06-01

    Samples of materials counted as perspective ones for use in the first-wall and construction elements in nuclear fusion reactors (FRs) with magnetic and inertial plasma confinement (W, Ti, Al, low-activated ferritic steel ‘Eurofer’ and some alloys) were irradiated in the dense plasma focus (DPF) device ‘Bora’ having a bank energy of ⩽5 kJ. The device generates hot dense (T ˜ 1 keV, n ˜ 1019 cm-3) deuterium plasma, powerful plasma streams (v ˜ 3 × 107 cm s-1) and fast (E ˜ 0.1 … 1.0 MeV) deuterons of power flux densities q up to 1010 and 1012 W cm-2 correspondingly. ‘Damage factor’ F = q × τ0.5 ensures an opportunity to simulate radiation loads (predictable for both reactors types) by the plasma/ion streams, which have the same nature and namely those parameters as expected in the FR modules. Before and after irradiation we provided investigations of our samples by means of a number of analytical techniques. Among them we used optical and scanning electron microscopy to understand character and parameters of damageability of the surface layers of the samples. Atomic force microscopy was applied to measure roughness of the surface after irradiation. These characteristics are quite important for understanding mechanisms and values of dust production in FR that may relate to tritium retention and emergency situations in FR facilities. We also applied two new techniques. For the surface we elaborated the portable x-ray diffractometer that combines x-ray single photon detection with high spectroscopic and angular resolutions. For bulk damageability investigations we applied an x-ray microCT system where x-rays were produced by a Hamamatsu microfocus source (150 kV, 500 µA, 5 µm minimum focal spot size). The detector was a Hamamatsu CMOS flat panel coupled to a fibre optic plate under the GOS scintillator. The reconstruction of three-dimensional data was run with Cobra 7.4 and DIGIX CT software while VG Studio Max 2.1, and Amira 5.3 were used for

  7. The electromagnetic Ram action of the plasma focus as a paradigm for the generation of cosmic rays and the gigantic jets in active galaxies

    Science.gov (United States)

    Bostick, W. H.; Nardi, V.

    1985-08-01

    Recent measurements of the energy spectrum of the plasma-focus-generated deuteron beam yield as spectrum of the form N(E)=(approx.) E to the -2.7 for 1MeV E 13 MeV. Other measurements show that the beta 1 electron beam which is generated simultaneously with the deuteron beam is interrupted into segments of spacing 25ps and duration approximately 4ps. A stuttering-electro-magnetic-ram (ser) model of the plasma focus in proposed which is similar to Raudorf's electronic ram which produces a similar spectrum for an electron beam for 1Mev E 10MeV. It is proposed that the cosmic ray spectrum and the giganic galactic jets are both generated by ser action near the centers of active galaxies.

  8. The electromagnetic ram action of the plasma focus as a paradigm for the generation of cosmic rays and the gigantic jets in active galaxies

    Science.gov (United States)

    Bostick, W. H.; Nardi, V.

    1985-01-01

    Recent measurements of the energy spectrum of the plasma-focus-generated deuteron beam yield as spectrum of the form N(E)=(approx.) E to the -2.7 for 1MeV E 13 MeV. Other measurements show that the beta 1 electron beam which is generated simultaneously with the deuteron beam is interrupted into segments of spacing 25ps and duration approximately 4ps. A stuttering-electro-magnetic-ram (ser) model of the plasma focus in proposed which is similar to Raudorf's electronic ram which produces a similar spectrum for an electron beam for 1Mev E 10MeV. It is proposed that the cosmic ray spectrum and the giganic galactic jets are both generated by ser action near the centers of active galaxies.

  9. NIPPLE DISCHARGE

    Directory of Open Access Journals (Sweden)

    T. N. Bukharova

    2008-01-01

    Full Text Available According to the data available in the literature, as high as 50% of women have benign breast tumors frequently accompanied by nip- ple discharge. Nipple discharge may be serous, bloody, purulent, and colostric. The most common causes are breast abscess, injury, drugs, prolactinoma, intraductal pappiloma, ductal ectasia, intraductal cancer (not more than 10%.

  10. Discharge Dialogue

    DEFF Research Database (Denmark)

    Horsbøl, Anders

    2012-01-01

    less attention has been given to medical patients, who are often elderly and suffer from multiple diseases. This paper addresses the latter issue with a case study of a local initiative to improve transition from hospital to home (care) for medical patients at a Danish hospital, in which a discharge...... coordinator, employed at the hospital, is supposed to anticipate discharge and serve as mediator between the hospital and the municipal home care system. Drawing on methods from discourse and interaction analysis, the paper studies the practice of the discharge coordinator in two encounters between patients...

  11. Evidence of nuclear fusion neutrons in an extremely small plasma focus device operating at 0.1 Joules

    Science.gov (United States)

    Soto, Leopoldo; Pavéz, Cristián; Moreno, José; Altamirano, Luis; Huerta, Luis; Barbaglia, Mario; Clausse, Alejandro; Mayer, Roberto E.

    2017-08-01

    We report on D-D fusion neutron emission in a plasma device with an energy input of only 0.1 J, within a range where fusion events have been considered very improbable. The results presented here are the consequence of scaling rules we have derived, thus being the key point to assure the same energy density plasma in smaller devices than in large machines. The Nanofocus (NF)—our device—was designed and constructed at the P4 Lab of the Chilean Nuclear Energy Commission. Two sets of independent measurements, with different instrumentation, were made at two laboratories, in Chile and Argentina. The neutron events observed are 20σ greater than the background. The NF plasma is produced from a pulsed electrical discharge using a submillimetric anode, in a deuterium atmosphere, showing empirically that it is, in fact, possible to heat and compress the plasma. The strong evidence presented here stretches the limits beyond what was expected. A thorough understanding of this could possibly tell us where the theoretical limits actually lie, beyond conjectures. Notwithstanding, a window is thus open for low cost endeavours for basic fusion research. In addition, the development of small, portable, safe nonradioactive neutron sources becomes a feasible issue.

  12. Ileostomy - discharge

    Science.gov (United States)

    ... foods that may block your stoma are raw pineapple, nuts and seeds, celery, popcorn, corn, dried fruits ( ... ask your doctor Living with your ileostomy Low-fiber diet Small bowel resection - discharge Total colectomy or ...

  13. Gallstones - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000196.htm Gallstones - discharge To use the sharing features on this page, please enable JavaScript. You have gallstones. These are hard, pebble-like deposits that formed ...

  14. Interstitial lung disease - adults - discharge

    Science.gov (United States)

    Diffuse parenchymal lung disease - discharge; Alveolitis - discharge; Idiopathic pulmonary pneumonitis - discharge; IPP - discharge; Chronic interstitial lung - discharge; Chronic respiratory interstitial lung - discharge; Hypoxia - interstitial lung - discharge

  15. Application of plasma focus installations for a study of the influence of deuterium cumulative flows on materials

    Indian Academy of Sciences (India)

    L I Ivanov; A I Dedyurin; I V Borovitskaya; O N Krokhin; V Ya Nikulin; S N Polukhin; A A Tikhomirov; A S Fedotov

    2003-12-01

    In this work, as an example of an application of the plasma focus (PF) device, we study the influence on alloys of vanadium of a cumulative flow producing in the PF device. The experiment was done in a 4-kJ PF device with various gas fillings and various anode shapes. It was found that the velocity of the axial cumulative flow depends on the type of gas and is about $5\\cdot 10^{7}$ cm/s for deuterium and $2\\cdot 10^{7}$ cm/s for argon fillings of plasma focus chamber; the shape of the flow is changed from a broad conical fly for deuterium to a quasi-one-directional stream for argon. The dynamics and structure of such flows are investigated by means of laser diagnostics and an image converter camera. The experiments show that cumulative flows produce various defects in tested samples. The appearance of a large number of cracks on the surface of vanadium under the impulse influence of deuterium plasma shows that pure vanadium cannot be used for the construction of thermonuclear fusion reactors. Such PF installations could also be used effectively for the study of other material and construction elements proposed for the use in thermonuclear machines.

  16. Neon soft x-ray emission studies from the UNU-ICTP plasma focus operated with longer than optimal anode length

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, M A [Faculty of Physics, University of Tabriz, Tabriz, Iran (Iran, Islamic Republic of); Verma, R [Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University (Singapore); Sobhanian, S [Faculty of Physics, University of Tabriz, Tabriz, Iran (Iran, Islamic Republic of); Wong, C S [Plasma Research Laboratory, Physics Department, University of Malaya, Kuala Lumpur (Malaysia); Lee, S [Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University (Singapore); Springham, S V [Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University (Singapore); Tan, T L [Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University (Singapore); Lee, P [Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University (Singapore); Rawat, R S [Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University (Singapore)

    2007-11-15

    The UNU-ICTP plasma focus with a significantly longer than conventional anode can still be a reasonably good neon soft x-ray (SXR) source. The highest average neon SXR yield of 3.3 J was achieved at 3 mbar. The time difference between the two first peaks of the voltage probe signal at the radial collapse phase was found to be inversely related to the SXR yield, i.e. the smaller the time difference, the higher the yield and vice versa. The estimation of average current sheath speeds using the shadowgraphic method coupled with laser and focus peak timing signals showed that the average axial rundown speed is similar to the one obtained for the optimal anode length but the average radial compression speed is decreased significantly. The range of pressure for a good neon SXR yield, however, has become much narrower, making efficient plasma focus operation a very sensitive function of the filling gas pressure for longer than the optimal anode length.

  17. Use of delayed gamma rays for active non-destructive assay of {sup 235}U irradiated by pulsed neutron source (plasma focus)

    Energy Technology Data Exchange (ETDEWEB)

    Andola, Sanjay; Niranjan, Ram [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kaushik, T.C., E-mail: tckk@barc.gov.in [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Rout, R.K. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, Ashwani; Paranjape, D.B.; Kumar, Pradeep; Tomar, B.S.; Ramakumar, K.L. [Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Gupta, S.C. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-07-01

    A pulsed neutron source based on plasma focus device has been used for active interrogation and assay of {sup 235}U by monitoring its delayed high energy γ-rays. The method involves irradiation of fissile material by thermal neutrons obtained after moderation of a burst of neutrons emitted upon fusion of deuterium in plasma focus (PF) device. The delayed gamma rays emitted from the fissile material as a consequence of induced fission were detected by a large volume sodium iodide (NaI(Tl)) detector. The detector is coupled to a data acquisition system of 2k input size with 2k ADC conversion gain. Counting was carried out in pulse height analysis mode for time integrated counts up to 100 s while the temporal profile of delayed gamma has been obtained by counting in multichannel scaling mode with dwell time of 50 ms. To avoid the effect of passive (natural) and active (from surrounding materials) backgrounds, counts have been acquired for gamma energy between 3 and 10 MeV. The lower limit of detection of {sup 235}U in the oxide samples with this set-up is estimated to be 14 mg.

  18. A 160 kJ dual plasma focus (DuPF) for fusion-relevant materials testing and nano-materials fabrication

    Science.gov (United States)

    Saw, S. H.; Damideh, V.; Chong, P. L.; Lee, P.; Rawat, R. S.; Lee, S.

    2014-08-01

    This paper summarizes PF-160 Dual Plasma Focus (DuPF) numerical experiments using the Lee Model code and preliminary 3D design drawings using SolidWorks software. This DuPF consists of two interchangeable electrodes enabling it to be optimized for both Slow Pinch Mode (SFM) and Fast Pinch Mode (FFM); the latter using a speed factor (SF) of 90 kA cm-1 Torr-0.5 for FFM in deuterium [S Lee et al, IEEE Trans Plasma Science 24, 1101-1105 (1996)]; and the former with SF of less than half that value for SFM. Starting with available 6 × 450 µF capacitors rated at 11kV (10% reversal), numerical experiments indicate safe operation at 9 kV, 6 Torr deuterium with FFM anode of 5 cm radius; producing intense ion beam and streaming plasma pulses which would be useful for studies of potential fusion reactor wall materials. On the other hand operating at 5 kV, 10 Torr deuterium with SFM anode of 10 cm radius leads to long-duration, uniform large-area flow which could be more suitable for synthesis of nano-materials. The dual plasma focus design is illustrated here with two figures showing FFM and SFM electrodes.

  19. Discharge Dialogue

    DEFF Research Database (Denmark)

    Horsbøl, Anders

    2012-01-01

    For several years, efforts have been made to strengthen collaboration between health professionals with different specializations and to improve patient transition from hospital to home (care). In the Danish health care system, these efforts have concentrated on cancer and heart diseases, whereas...... less attention has been given to medical patients, who are often elderly and suffer from multiple diseases. This paper addresses the latter issue with a case study of a local initiative to improve transition from hospital to home (care) for medical patients at a Danish hospital, in which a discharge...... coordinator, employed at the hospital, is supposed to anticipate discharge and serve as mediator between the hospital and the municipal home care system. Drawing on methods from discourse and interaction analysis, the paper studies the practice of the discharge coordinator in two encounters between patients...

  20. Angioplasty and stent - heart - discharge

    Science.gov (United States)

    Drug-eluting stents - discharge; PCI - discharge; Percutaneous coronary intervention - discharge; Balloon angioplasty - discharge; Coronary angioplasty - discharge; Coronary artery angioplasty - discharge; Cardiac ...

  1. Dense Plasma Focus as Collimated Source of D-D Fusion Neutron Beams for Irradiation Experiences and Study of Emitted Radiations

    Science.gov (United States)

    Milanese, M.; Niedbalski, J.; Moroso, R.; Guichón, S.; Supán, J.

    2008-04-01

    A "table-top" 2 kJ, 250 kA plasma focus, the PACO (Plasma AutoConfinado), designed by the Dense Plasma Group of IFAS is used in its optimum regime for neutron yield for obtaining collimated pulsed neutron beams (100 ns). A simple and low-cost shielding arrangement was developed in order to fully eliminate the 2.45 MeV neutrons generated in the PACO device (108 per shot at 31 kV, 1-2 mbar). Conventional neutron diagnostics: scintillator-photomultiplier (S-PMT), silver activation counters (SAC), etc., are used to determine the minimum width of the shielding walls. Emission of very hard electromagnetic pulses is also studied. Collimation using lead and copper plates is made to determine the localization of the very hard X-ray source. The maximum energy of the continuum photon distribution is estimated in 0,6 MeV using a system of filters.

  2. Dense Plasma Focus: physics and applications (radiation material science, single-shot disclosure of hidden illegal objects, radiation biology and medicine, etc.)

    Science.gov (United States)

    Gribkov, V. A.; Miklaszewski, R.; Paduch, M.; Zielinska, E.; Chernyshova, M.; Pisarczyk, T.; Pimenov, V. N.; Demina, E. V.; Niemela, J.; Crespo, M.-L.; Cicuttin, A.; Tomaszewski, K.; Sadowski, M. J.; Skladnik-Sadowska, E.; Pytel, K.; Zawadka, A.; Giannini, G.; Longo, F.; Talab, A.; Ul'yanenko, S. E.

    2015-03-01

    The paper presents some outcomes obtained during the year of 2013 of the activity in the frame of the International Atomic Energy Agency Co-ordinated research project "Investigations of Materials under High Repetition and Intense Fusion-Relevant Pulses". The main results are related to the effects created at the interaction of powerful pulses of different types of radiation (soft and hard X-rays, hot plasma and fast ion streams, neutrons, etc. generated in Dense Plasma Focus (DPF) facilities) with various materials including those that are counted as perspective ones for their use in future thermonuclear reactors. Besides we discuss phenomena observed at the irradiation of biological test objects. We examine possible applications of nanosecond powerful pulses of neutrons to the aims of nuclear medicine and for disclosure of hidden illegal objects. Special attention is devoted to discussions of a possibility to create extremely large and enormously diminutive DPF devices and probabilities of their use in energetics, medicine and modern electronics.

  3. Study of the effect of pyrex and quartz insulators on X-ray intensity in a 4 kJ plasma focus device

    Science.gov (United States)

    Koohestani, Saeedeh; Habibi, Morteza; Amrollahi, Reza

    2013-06-01

    In this paper we study the soft X-ray (SXR) and hard X-ray (HXR) intensity produced in different insulator sleeves by a 4 kJ plasma focus device (APF) using filtered PIN-diodes and a fast scintillation detector. The experiments were performed for a great number of neon filling gas pressures at voltages of 11, 12 and 13 kV. Lengths of 40 and 50 mm look optimal to yield the most SXR intensity for the Pyrex and Quartz insulators respectively. The device appears to optimize much better for Pyrex insulator than the Quartz. For Pyrex and Quartz insulators, the lengths of 40 mm and 50 mm seem optimal to yield maximum HXR intensity, respectively.

  4. Axial magnetic field and toroidally streaming fast ions in the dense plasma focus are natural consequences of conservation laws in the curved axisymmetric geometry of the current sheath

    CERN Document Server

    Auluck, S K H

    2014-01-01

    Direct measurement of axial magnetic field in the PF-1000 dense plasma focus (DPF), and its reported correlation with neutron emission, call for a fresh look at previous reports of existence of axial magnetic field component in the DPF from other laboratories, and associated data suggesting toroidal directionality of fast ions participating in fusion reactions, with a view to understand the underlying physics. In this context, recent work dealing with application of the hyperbolic conservation law formalism to the DPF is extended in this paper to a curvilinear coordinate system, which reflects the shape of the DPF current sheath. Locally-unidirectional shock propagation in this coordinate system enables construction of a system of 7 one-dimensional hyperbolic conservation law equations with geometric source terms, taking into account all the components of magnetic field and flow velocity. Rankine-Hugoniot jump conditions for this system lead to expressions for the axial magnetic field and three components of ...

  5. Electron Temperature Measurement Using PIN Diodes as Detectors to Record the X-ray Pulses from a Low-Energy Mather-Type Plasma Focus

    Institute of Scientific and Technical Information of China (English)

    M. Asif; Amna Ikram

    2004-01-01

    In the experiment to determine the plasma electron temperature, a modified multichannel PIN diodes assembly is used as detectors to record the X-ray pulses from a low-energy Mather-type plasma focus device energized by a 32μF, 15 kV (3.6 k J) single capacitor, with deuterium as a filling gas. The ratio of the integrated bremsstrahlung emission transmitting through foils to the total incident flux as a function of foil thickness at various temperatures is obtained for foil absorbers of material. Using 3μm, 6μm, 9μm,12μm,15μm and 18μm thick aluminium absorbers, the transmitted X-ray flux is detected. By comparing the experimental and theoretical curves through a computer program, the plasma electron temperature is determined. Results show that the deuterium focus plasma electron temperature is about 800 eV.

  6. Synthesis of TiN/a-Si3N4 thin film by using a Mather type dense plasma focus system

    Institute of Scientific and Technical Information of China (English)

    T.Hussain; R.Ahmad; N.Khalid; Z.A.Umar; A.Hussnain

    2013-01-01

    A 2.3 kJ Mather type pulsed plasma focus device was used for the synthesis of a TiN/a-Si3N4 thin film at room temperature.The film was characterized using X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS),scanning electron microscopy (SEM),and atomic force microscopy (AFM).The XRD pattern confirms the growth of polycrystalline TiN thin film.The XPS results indicate that the synthesized film is non-stoichiometric and contains titanium nitride,silicon nitride,and a phase of silicon oxy-nitride.The SEM and AFM results reveal that the surface of the synthesized film is quite smooth with 0.59 nm roughness (root-mean-square).

  7. Ulcerative colitis - discharge

    Science.gov (United States)

    Inflammatory bowel disease - ulcerative colitis - discharge; Ulcerative proctitis - discharge; Colitis - discharge ... were in the hospital because you have ulcerative colitis. This is a swelling of the inner lining ...

  8. Pediatric heart surgery - discharge

    Science.gov (United States)

    ... discharge; Heart valve surgery - children - discharge; Heart surgery - pediatric - discharge; Heart transplant - pediatric - discharge ... Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics . 20th ed. Philadelphia, PA: Elsevier; 2016:chap 434. ...

  9. Lung surgery - discharge

    Science.gov (United States)

    ... Lung biopsy - discharge; Thoracoscopy - discharge; Video-assisted thoracoscopic surgery - discharge; VATS - discharge ... milk) for 2 weeks after video-assisted thoracoscopic surgery and 6 to 8 weeks after open surgery. ...

  10. Refractive corneal surgery - discharge

    Science.gov (United States)

    Nearsightedness surgery - discharge; Refractive surgery - discharge; LASIK - discharge; PRK - discharge ... You had refractive corneal surgery to help improve your vision. This surgery uses a laser to reshape your cornea. It corrects mild-to-moderate nearsightedness, ...

  11. Measurement of ion beam angular distribution at different helium gas pressures in a plasma focus device by large-area polycarbonate detectors

    Energy Technology Data Exchange (ETDEWEB)

    Sohrabi, M.; Habibi, M., E-mail: mortezahabibi@gmail.com; Ramezani, V. [Amirkabir University of Technology, Energy Engineering and Physics Department (Iran, Islamic Republic of)

    2017-02-15

    The paper presents an experimental study and analysis of full helium ion density angular distributions in a 4-kJ plasma focus device (PFD) at pressures of 10, 15, 25, and 30 mbar using large-area polycarbonate track detectors (PCTDs) (15-cm etchable diameter) processed by 50-Hz-HV electrochemical etching (ECE). Helium ion track distributions at different pressures, in particular, at the main axis of the PFD are presented. Maximum ion track density of ~4.4 × 10{sup 4} tracks/cm{sup 2} was obtained in the PCTD placed 6 cm from the anode. The ion distributions for all pressures applied are ring-shaped, which is possibly due to the hollow cylindrical copper anode used. The large-area PCTD processed by ECE proves, at the present state-of-theart, a superior method for direct observation and analysis of ion distributions at a glance with minimum efforts and time. Some observations of the ion density distributions at different pressures are reported and discussed.

  12. Re-appraisal and extension of the Gratton-Vargas two-dimensional analytical snowplow model of plasma focus - Part II: Looking at the singularity

    CERN Document Server

    Auluck, S K H

    2016-01-01

    The Gratton-Vargas snowplow model, recently revisited and expanded (S K H Auluck, Physics of Plasmas, 20, 112501 (2013)), has given rise to significant new insights into some aspects of the Dense Plasma Focus (DPF), in spite of being a purely kinematic description having no reference to plasma phenomena. It is able to provide a good fit to the experimental current waveforms in at least 4 large facilities. It has been used for construction of a local curvilinear frame of reference, in which conservation laws for mass, momentum and energy can be reduced to effectively-one-dimensional hyperbolic conservation law equations. Its utility in global parameter optimization of device parameters has been demonstrated. These features suggest that the Gratton-Vargas model deserves a closer look at its supposed limitations near the singular phase of the DPF. This paper presents a discussion of its development near the device axis, based on the original work of Gratton and Vargas, with some differences. It is shown that the...

  13. The effects of pre-ionization using a shunt resistor on reproducibility of the x-ray emission in a dense plasma focus device

    Science.gov (United States)

    Piriaei, D.; Yousefi, H. R.; Mahabadi, T. D.; SalarElahi, A.; Ghoranneviss, M.

    2017-08-01

    In this research, the effects of pre-ionization using a shunt resistor on reproducibility of x-ray emission in a Mather type plasma focus device have been studied. This technique increased the intensities of the emitted x-rays from argon as the filling gas of the device and made the x-ray yields with similar intensities reproducible. A Mirnov coil was also used to record the variations of the plasma's magnetic field, and the wavelet spectrums of these recorded signals showed the reduced instabilities due to the application of the pre-ionization technique. Moreover, it was demonstrated that this technique was capable of reducing the number of initial runaway electrons that could increase the impurities and instabilities inside the plasma. In addition to the above-mentioned features, this technique could improve the uniform formation of the current sheath during the breakdown phase that might later lead to a high quality pinch and high intensity emitted x-rays.

  14. Early effects comparison of X-rays delivered at high-dose-rate pulses by a plasma focus device and at low dose rate on human tumour cells.

    Science.gov (United States)

    Virelli, A; Zironi, I; Pasi, F; Ceccolini, E; Nano, R; Facoetti, A; Gavoçi, E; Fiore, M R; Rocchi, F; Mostacci, D; Cucchi, G; Castellani, G; Sumini, M; Orecchia, R

    2015-09-01

    A comparative study has been performed on the effects of high-dose-rate (DR) X-ray beams produced by a plasma focus device (PFMA-3), to exploit its potential medical applications (e.g. radiotherapy), and low-DR X-ray beams produced by a conventional source (XRT). Experiments have been performed at 0.5 and 2 Gy doses on a human glioblastoma cell line (T98G). Cell proliferation rate and potassium outward currents (IK) have been investigated by time lapse imaging and patch clamp recordings. The results showed that PFMA-3 irradiation has a greater capability to reduce the proliferation rate activity with respect to XRT, while it does not affect IK of T98G cells at any of the dose levels tested. XRT irradiation significantly reduces the mean IK amplitude of T98G cells only at 0.5 Gy. This work confirms that the DR, and therefore the source of radiation, is crucial for the planning and optimisation of radiotherapy applications.

  15. Study of x-ray emission from a table top plasma focus and its application as an x-ray backlighter

    Science.gov (United States)

    Beg, F. N.; Ross, I.; Lorenz, A.; Worley, J. F.; Dangor, A. E.; Haines, M. G.

    2000-09-01

    A study of a 2 kJ, 200 kA, table top plasma focus device as an intense x-ray source is reported. The x-ray yield from a number of gases, (deuterium, nitrogen, neon, argon, and xenon) is measured as a function of filling pressure and in neon as a function of anode length. In gases with Zplasma implodes to form a uniform cylindrical column, whereas for Z⩾18, the plasma consists of a number of hot spots. A maximum x-ray yield of 16.6 J and pulse length of 10-15 ns was obtained in neon. The x-ray emission was established to be due to H- and He-like line radiation. The temperature estimated from spectroscopic observations was about 300-400 eV at an electron density of (3-5)×1020cm-3 in neon. At low pressures in neon, hard x-ray radiation, presumably due to electron beams was dominant. Mesh images of different wire materials were recorded at the optimum pressure in neon as a proof of principle for x-ray backlighting.

  16. A novel technique based on a plasma focus device for nano-porous gallium nitride formation on P-type silicon

    Science.gov (United States)

    Sharifi Malvajerdi, S.; Salar Elahi, A.; Habibi, M.

    2017-04-01

    A new deposition formation was observed with a Mather-type Plasma Focus Device (MPFD). MPFD was unitized to fabricate porous Gallium Nitride (GaN) on p-type Silicon (Si) substrate with a (100) crystal orientation for the first time in a deposition process. GaN was deposited on Si with 4 and 7 shots. The samples were subjected to a 3 phase annealing procedure. First, the semiconductors were annealed in the PFD with nitrogen plasma shots after their deposition. Second, a thermal chemical vapor deposition annealed the samples for 1 h at 1050 °C by nitrogen gas at a pressure of 1 Pa. Finally, an electric furnace annealed the samples for 1 h at 1150 °C with continuous flow of nitrogen. Porous GaN structures were observed by Field emission scanning electron microscopy and atomic force microscopy. Furthermore, X-Ray diffraction analysis was carried out to determine the crystallinity of GaN after the samples were annealed. Energy-Dispersive X-Ray Spectroscopy indicated the amount of gallium, nitrogen, and oxygen due to the self-oxidation of the samples. Photoluminescence spectroscopy revealed emissions at 2.94 eV and 3.39 eV, which shows that hexagonal wurtzite crystal structures were formed.

  17. An ultra miniature pinch-focus discharge

    Energy Technology Data Exchange (ETDEWEB)

    Soto, L.; Pavez, C.; Moreno, J. [Comision Chilena de Energia Nuclear, Santiago (Chile); Pavez, C. [Universidad de Concepcion (Chile); Barbaglia, M.; Clausse, A. [Universidad Nacional del Centro, Pladema-CNEA-Conicet, Tandil (Argentina)

    2004-07-01

    As a way to investigate the minimum energy to produce a pinch plasma focus discharge, an ultra miniature device has been designed and constructed (nano focus NF: 5 nF, 5-10 kV, 5-10 kA, 60-250 mJ, 16 ns time to peak current). Sub-millimetric anode radius covered by a coaxial insulator were used for experiments in hydrogen. Evidence of pinch was observed in electrical signals in discharges operating at 60 mJ. A single-frame image converter camera (4 ns exposure) was used to obtain plasma images in the visible range. The dynamics observed from the photographs is consistent with: a) formation of a plasma sheath close to the insulator surface, b) fast axial motion of the plasma sheath, c) radial compression over the anode, and d) finally the plasma is detached from the anode in the axial direction. The total time since stage a) to d) was observed to be about 30 ns. X ray and neutron emission is being studied. Neutron yield of the order of 10{sup 3} neutrons per shot is expected for discharges operating in deuterium at 10 kA. (authors)

  18. A dense plasma focus-based neutron source for a single-shot detection of illicit materials and explosives by a nanosecond neutron pulse

    Energy Technology Data Exchange (ETDEWEB)

    Gribkov, V A; Latyshev, S V [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Miklaszewski, R A; Chernyshova, M [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Drozdowicz, K; Wiacek, U [Institute of Nuclear Physics, Krakow (Poland); Tomaszewski, K [ACS Ltd, Warsaw (Poland); Lemeshko, B D [N L Dukhov All-Russian Institute of Automation, Moscow (Russian Federation)], E-mail: gribkovv@yahoo.com

    2010-03-15

    Recent progress in a single-pulse Nanosecond Impulse Neutron Investigation System (NINIS) intended for interrogation of hidden objects by means of measuring elastically scattered neutrons is presented in this paper. The method uses very bright neutron pulses having duration of the order of 10 ns only, which are generated by dense plasma focus (DPF) devices filled with pure deuterium or DT mixture as a working gas. The small size occupied by the neutron bunch in space, number of neutrons per pulse and mono-chromaticity ({delta}E/E{approx}1%) of the neutron spectrum provides the opportunity to use a time-of-flight (TOF) technique with flying bases of about a few metres. In our researches we used DPF devices having bank energy in the range 2-7 kJ. The devices generate a neutron yield of the level of 10{sup 8}-10{sup 9} 2.45 MeV and 10{sup 10}-10{sup 11} 14 MeV neutrons per pulse with pulse duration {approx}10-20 ns. TOF base in the tests was 2.2-18.5 m. We have demonstrated the possibility of registering of neutrons scattered by the substances under investigation-1 litre bottles with methanol (CH{sub 3}OH), phosphoric (H{sub 2}PO{sub 4}) and nitric (HNO{sub 3}) acids as well as a long object-a 1 m gas tank filled with deuterium at high pressure. It is shown that the above mentioned short TOF bases and relatively low neutron yields are enough to distinguish different elements' nuclei composing the substance under interrogation and to characterize the geometry of lengthy objects in some cases. The wavelet technique was employed to 'clean' the experimental data registered. The advantages and restrictions of the proposed and tested NINIS technique in comparison with other methods are discussed.

  19. A dense plasma focus-based neutron source for a single-shot detection of illicit materials and explosives by a nanosecond neutron pulse

    Science.gov (United States)

    Gribkov, V. A.; Latyshev, S. V.; Miklaszewski, R. A.; Chernyshova, M.; Drozdowicz, K.; Wiącek, U.; Tomaszewski, K.; Lemeshko, B. D.

    2010-03-01

    Recent progress in a single-pulse Nanosecond Impulse Neutron Investigation System (NINIS) intended for interrogation of hidden objects by means of measuring elastically scattered neutrons is presented in this paper. The method uses very bright neutron pulses having duration of the order of 10 ns only, which are generated by dense plasma focus (DPF) devices filled with pure deuterium or DT mixture as a working gas. The small size occupied by the neutron bunch in space, number of neutrons per pulse and mono-chromaticity (ΔE/E~1%) of the neutron spectrum provides the opportunity to use a time-of-flight (TOF) technique with flying bases of about a few metres. In our researches we used DPF devices having bank energy in the range 2-7 kJ. The devices generate a neutron yield of the level of 108-109 2.45 MeV and 1010-1011 14 MeV neutrons per pulse with pulse duration ~10-20 ns. TOF base in the tests was 2.2-18.5 m. We have demonstrated the possibility of registering of neutrons scattered by the substances under investigation—1 litre bottles with methanol (CH3OH), phosphoric (H2PO4) and nitric (HNO3) acids as well as a long object—a 1 m gas tank filled with deuterium at high pressure. It is shown that the above mentioned short TOF bases and relatively low neutron yields are enough to distinguish different elements' nuclei composing the substance under interrogation and to characterize the geometry of lengthy objects in some cases. The wavelet technique was employed to 'clean' the experimental data registered. The advantages and restrictions of the proposed and tested NINIS technique in comparison with other methods are discussed.

  20. Concussion - adults - discharge

    Science.gov (United States)

    Brain injury - concussion - discharge; Traumatic brain injury - concussion - discharge; Closed head injury - concussion - discharge ... Getting better from a concussion takes days to weeks or even months. ... have trouble concentrating, or be unable to remember things. ...

  1. Tennis elbow surgery - discharge

    Science.gov (United States)

    ... epicondylitis surgery - discharge; Lateral tendinosis surgery - discharge; Lateral tennis elbow surgery - discharge ... long as you are told. This helps ensure tennis elbow will not return. You may be prescribed a ...

  2. Asthma - child - discharge

    Science.gov (United States)

    Pediatric asthma - discharge; Wheezing - discharge; Reactive airway disease - discharge ... Your child has asthma , which causes the airways of the lungs to swell and narrow. In the hospital, the doctors and nurses helped ...

  3. Eye muscle repair - discharge

    Science.gov (United States)

    ... Lazy eye repair - discharge; Strabismus repair - discharge; Extraocular muscle surgery - discharge ... You or your child had eye muscle repair surgery to correct eye muscle ... term for crossed eyes is strabismus. Children most often ...

  4. Neck dissection - discharge

    Science.gov (United States)

    Radical neck dissection - discharge; Modified radical neck dissection - discharge; Selective neck dissection - discharge ... 659-665. Robbins KT, Samant S, Ronen O. Neck dissection. In: Flint PW, Haughey BH, Lund V, et ...

  5. ACL reconstruction - discharge

    Science.gov (United States)

    Anterior cruciate ligament reconstruction - discharge; ACL reconstruction - discharge ... had surgery to reconstruct your anterior cruciate ligament (ACL). The surgeon drilled holes in the bones of ...

  6. Calibration of the RSS-131 high efficiency ionization chamber for radiation dose monitoring during plasma experiments conducted on plasma focus device

    Science.gov (United States)

    Szewczak, Kamil; Jednoróg, Sławomir

    2014-10-01

    Plasma research poses a radiation hazard. Due to the program of deuterium plasma research using the PF-1000 device, it is an intensive source of neutrons (up to 1011 n · pulse -1) with energy of 2,45 MeV and ionizing electromagnetic radiation with a broad energy spectrum. Both types of radiation are mostly emitted in ultra-short pulses (˜100 ns). The aim of this work was to test and calibrate the RSS-131 radiometer for its application in measurements of ultra-short electromagnetic radiation pulses with broad energy spectrum emitted during PF-1000 discharge. In addition, the results of raw measurements performed in the control room are presented.

  7. Foot amputation - discharge

    Science.gov (United States)

    Amputation - foot - discharge; Trans-metatarsal amputation - discharge ... You have had a foot amputation. You may have had an accident, or your foot may have had an infection or disease and doctors could not save ...

  8. Chronic obstructive pulmonary disease - adults - discharge

    Science.gov (United States)

    COPD - adults - discharge; Chronic obstructive airways disease - adults - discharge; Chronic obstructive lung disease - adults - discharge; Chronic bronchitis - adults - discharge; Emphysema - adults - discharge; Bronchitis - ...

  9. Predicting tile drainage discharge

    DEFF Research Database (Denmark)

    Iversen, Bo Vangsø; Kjærgaard, Charlotte; Petersen, Rasmus Jes;

    of the water load coming from the tile drainage system is therefore essential. This work aims at predicting tile drainage discharge using dynamic as well as a statistical predictive models. A large dataset of historical tile drain discharge data, daily discharge values as well as yearly average values were......More than 50 % of Danish agricultural areas are expected to be artificial tile drained. Transport of water and nutrients through the tile drain system to the aquatic environment is expected to be significant. For different mitigation strategies such as constructed wetlands an exact knowledge...... used in the analysis. For the dynamic modelling, a simple linear reservoir model was used where different outlets in the model represented tile drain as well as groundwater discharge outputs. This modelling was based on daily measured tile drain discharge values. The statistical predictive model...

  10. CO-AXIAL DISCHARGES

    Science.gov (United States)

    Luce, J.S.; Smith, L.P.

    1960-11-22

    A method and apparatus are given for producing coaxial arc discharges in an evacuated enclosure and within a strong, confining magnetic field. The arcs are maintained at a high potential difference. Electrons will diffuse to the more positive arc from the negative arc, and positive ions will diffuse from the more positive arc to the negative arc. Coaxial arc discharges have the advantage that ions which return to strike the positive arc discharge will lose no energy since they do not strike a solid wall or electrode. Those discharges are useful in confining an ionized plasma between the discharges, and have the advantage of preventing impurities from the walls of the enclosure from entering ihe plasma area because of the arc barrier set up bv the cylindrical outer arc.

  11. EFFECTIVE DISCHARGE CALCULATION GUIDE

    Institute of Scientific and Technical Information of China (English)

    D.S.BIEDENHARN; C.R.THORNE; P.J.SOAR; R.D.HEY; C.C.WATSON

    2001-01-01

    This paper presents a procedure for calculating the effective discharge for rivers with alluvial channels.An alluvial river adjusts the bankfull shape and dimensions of its channel to the wide range of flows that mobilize the boundary sediments. It has been shown that time-averaged river morphology is adjusted to the flow that, over a prolonged period, transports most sediment. This is termed the effective discharge.The effective discharge may be calculated provided that the necessary data are available or can be synthesized. The procedure for effective discharge calculation presented here is designed to have general applicability, have the capability to be applied consistently, and represent the effects of physical processes responsible for determining the channel, dimensions. An example of the calculations necessary and applications of the effective discharge concept are presented.

  12. Re-appraisal and extension of the Gratton-Vargas two-dimensional analytical snowplow model of plasma focus - III: Scaling theory for high pressure operation and its implications

    CERN Document Server

    Auluck, S K H

    2016-01-01

    Recent work on the revised Gratton-Vargas model has demonstrated that there are some aspects of Dense Plasma Focus (DPF) which are not sensitive to details of plasma dynamics and are well captured in an oversimplified model assumption which contains very little plasma physics. A hyperbolic conservation law formulation of DPF physics reveals the existence of a velocity threshold related to specific energy of dissociation and ionization, above which, the work done during shock propagation is adequate to ensure dissociation and ionization of the gas being ingested. These developments are utilized to formulate an algorithmic definition of DPF optimization that is valid in a wide range of applications, not limited to neutron emission. A universal scaling theory of DPF design optimization is proposed and illustrated for designing devices working at one or two orders higher pressure of deuterium than the current practice of designs optimized at pressures less than 10 mbar of deuterium. These examples show that the u...

  13. Filament Discharge Phenomena in Fingerprint Acquisition by Dielectric Barrier Discharge

    Institute of Scientific and Technical Information of China (English)

    WENG Ming; XU Weijun; LIU Qiang

    2007-01-01

    In this paper, the dielectric barrier discharge fingerprint acquisition technique is introduced. The filament discharge phenomena were observed in the process of fingerprint acquisition. The filament discharge reduced the quality of fingerprint images. Obviously, it was necessary to eliminate streamer discharges in order to get good fingerprint images. The streamer discharge was considered to be the cause of the filament discharge in the experiment. The relationship between the critical electric field and the discharge gap was calculated with the Raether's model of streamer discharge. The calculated results and our experiment proved that it would be difficult for the streamer discharge to occur when the discharge gap was narrow. With a narrow discharge gap, the discharge was homogeneous, and the fingerprint images were clear and large in area. The images obtained in the experiment are very suitable for fingerprint identification as they contain more information.

  14. Capacitor discharge engineering

    CERN Document Server

    Früngel, Frank B A

    1976-01-01

    High Speed Pulse Technology, Volume III: Capacitor Discharge Engineering covers the production and practical application of capacitor dischargers for the generation and utilization of high speed pulsed of energy in different forms. This nine-chapter volume discusses the principles of electric current, voltage, X-rays, gamma rays, heat, beams of electrons, neutrons and ions, magnetic fields, sound, and shock waves in gases and liquids. Considerable chapters consider the applications of capacitor discharges, such as impulse hardening of steel, ultrapulse welding of precision parts, X-ray flash t

  15. Abdominal radiation - discharge

    Science.gov (United States)

    Radiation - abdomen - discharge; Cancer - abdominal radiation; Lymphoma - abdominal radiation ... When you have radiation treatment for cancer, your body goes through changes. About 2 weeks after radiation treatment starts, you might notice changes ...

  16. Chest radiation - discharge

    Science.gov (United States)

    Radiation - chest - discharge; Cancer - chest radiation; Lymphoma - chest radiation ... When you have radiation treatment for cancer, your body goes through changes. About 2 weeks after your first treatment: It may be hard ...

  17. Breast radiation - discharge

    Science.gov (United States)

    Radiation - breast - discharge ... away around 4 to 6 weeks after the radiation treatment is over. You may notice changes in ... breast looks or feels (if you are getting radiation after a lumpectomy). These changes include: Soreness or ...

  18. Corneal transplant - discharge

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000243.htm Corneal transplant - discharge To use the sharing features on this page, please enable JavaScript. You had a corneal transplant. Most of the tissue of your cornea (the ...

  19. Brain radiation - discharge

    Science.gov (United States)

    Radiation - brain - discharge; Cancer-brain radiation; Lymphoma - brain radiation; Leukemia - brain radiation ... Decadron) while you are getting radiation to the brain. It may make you hungrier, cause leg swelling ...

  20. Pneumonia - children - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000011.htm Pneumonia in children - discharge To use the sharing features ... this page, please enable JavaScript. Your child has pneumonia, which is an infection in the lungs. In ...

  1. Pneumonia - adults - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000017.htm Pneumonia in adults - discharge To use the sharing features on this page, please enable JavaScript. You have pneumonia, which is an infection in your lungs. In ...

  2. Inguinal hernia - discharge

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000274.htm Inguinal hernia repair - discharge To use the sharing features on ... your child had surgery to repair an inguinal hernia caused by a weakness in the abdominal wall ...

  3. Cosmetic breast surgery - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000273.htm Cosmetic breast surgery - discharge To use the sharing features on this page, please enable JavaScript. You had cosmetic breast surgery to change the size or shape ...

  4. Pectus excavatum - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000298.htm Pectus excavatum - discharge To use the sharing features on this ... You or your child had surgery to correct pectus excavatum. This is a deformity of the front of ...

  5. Hip fracture - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000168.htm Hip fracture - discharge To use the sharing features on this page, please enable JavaScript. Hip fracture surgery is done to repair a break in ...

  6. Capacitor discharge pulse analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Michael Sean; Griffiths, Stewart K.; Tanner, Danelle Mary

    2013-08-01

    Capacitors used in firing sets and other high discharge current applications are discharge tested to verify performance of the capacitor against the application requirements. Parameters such as capacitance, inductance, rise time, pulse width, peak current and current reversal must be verified to ensure that the capacitor will meet the application needs. This report summarizes an analysis performed on the discharge current data to extract these parameters by fitting a second-order system model to the discharge data and using this fit to determine the resulting performance metrics. Details of the theory and implementation are presented. Using the best-fit second-order system model to extract these metrics results in less sensitivity to noise in the measured data and allows for direct extraction of the total series resistance, inductance, and capacitance.

  7. Pelvic radiation - discharge

    Science.gov (United States)

    Radiation of the pelvis - discharge; Cancer treatment - pelvic radiation; Prostate cancer - pelvic radiation; Ovarian cancer - pelvic radiation; Cervical cancer - pelvic radiation; Uterine cancer - pelvic radiation; Rectal cancer - pelvic radiation

  8. Identifying discharge practice training needs.

    Science.gov (United States)

    Lees, L; Emmerson, K

    A training needs analysis tool was developed to identify nurses' discharge training needs and to improve discharge practice. The tool includes 49 elements of discharge practice subdivided into four areas: corporate, operational, clinical and nurse-led discharge. The tool was disseminated to 15 wards on two hospital sites with assistance from the practice development team. Analysis of discharge training is important to assess discharge training needs and to identify staff who may assist with training.

  9. Microwave Discharge Ion Sources

    CERN Document Server

    Celona, L

    2013-01-01

    This chapter describes the basic principles, design features and characteristics of microwave discharge ion sources. A suitable source for the production of intense beams for high-power accelerators must satisfy the requirements of high brightness, stability and reliability. The 2.45 GHz off-resonance microwave discharge sources are ideal devices to generate the required beams, as they produce multimilliampere beams of protons, deuterons and singly charged ions. A description of different technical designs will be given, analysing their performance, with particular attention being paid to the quality of the beam, especially in terms of its emittance.

  10. MANAGEMENT OF VAGINAL DISCHARGE

    African Journals Online (AJOL)

    Enrique

    Vaginal infection is one of the top 25 reasons for women to consult doctors in the. USA. The 3 most common ... VAGINAL DISCHARGE IN POSTMENOPAUSAL WOMEN. In this age group, the .... More than one host fac- tor may be involved and ...

  11. Novel Molecular Discharges

    NARCIS (Netherlands)

    Hilbig, R.; Koerber, A.; Schwan, S.; Hayashi, D.

    2011-01-01

    A systematic investigation into halides and ~oxides showed the high potential of transition metal oxides as visible radiators for highly efficient gas discharge light sources. Zirconium monoxide (ZrO) has been identified as most promising candidate combining highly attractive green and red emission

  12. Electrical Discharge Machining.

    Science.gov (United States)

    Montgomery, C. M.

    The manual is for use by students learning electrical discharge machining (EDM). It consists of eight units divided into several lessons, each designed to meet one of the stated objectives for the unit. The units deal with: introduction to and advantages of EDM, the EDM process, basic components of EDM, reaction between forming tool and workpiece,…

  13. Flight Model Discharge System

    Science.gov (United States)

    1988-06-01

    Dielectric Sensor ................................... 12 5 ESA S/N 001 ......................................... 24 6 Preliminary Test Sequence...71 28 Optical Transmission Loss of Contamination "Witness" Slide 3 .................................. 72 29 Apparatus used in FMDS Spectroscopic...Monitor ( TPU ). This sensor detects the electromagnetic pulses generated by the onset of arcing. (2) An active discharge device (plasma source). (3) A

  14. Discharge pulse phenomenology

    Science.gov (United States)

    Frederickson, A. R.

    1985-01-01

    A model was developed which places radiation induced discharge pulse results into a unified conceptual framework. Only two phenomena are required to interpret all space and laboratory results: (1) radiation produces large electrostatic fields inside insulators via the trapping of a net space charge density; and (2) the electrostatic fields initiate discharge streamer plasmas similar to those investigated in high voltage electrical insulation materials; these streamer plasmas generate the pulsing phenomena. The apparent variability and diversity of results seen is an inherent feature of the plasma streamer mechanism acting in the electric fields which is created by irradiation of the dielectrics. The implications of the model are extensive and lead to constraints over what can be done about spacecraft pulsing.

  15. Electrostatic Discharge Training Manual

    Science.gov (United States)

    1980-09-01

    NAVSEA SE 003-AA-TRN-OO LEYE V ELECTROSTATIC DISCHARGE TRAINING MANUAL s DTIC ,T OF I!ELECTE, ,4MA 0W\\R 9 981 E PUBLISHED BY DIRECTION OF COMMANDER...AS: F (QIQ2 . . . ................................................. (1) WHERE: F = FORCE ( NEWTONS ) Q, AND Q2 = MAGNITUDES OF THE CHARGES (COULOMB) R...RATIONALIZED MKS UNITS IN EQUATION (1), WE HAVE: & I 9(5 X 1 - )(lO ř I ’ 32 I I I I. & I = .5 NEWTON

  16. Electrochemical Discharge Machining Process

    Directory of Open Access Journals (Sweden)

    Anjali V. Kulkarni

    2007-09-01

    Full Text Available Electrochemical discharge machining process is evolving as a promising micromachiningprocess. The experimental investigations in the present work substantiate this trend. In the presentwork, in situ, synchronised, transient temperature and current measurements have been carriedout. The need for the transient measurements arose due to the time-varying nature of the dischargeformation and time varying circuit current. Synchronised and transient measurements revealedthe discrete nature of the process. It also helped in formulating the basic mechanism for thedischarge formation and the material removal in the process. Temperature profile on workpieceand in electrochemical discharge machining cell is experimentally measured using pyrometer,and two varieties of K-type thermocouples. Surface topography of the discharge-affected zoneson the workpiece has been carried out using scanning electron microscope. Measurements andsurface topographical studies reveal the potential use of this process for machining in micronregime. With careful experimental set-up design, suitable supply voltage and its polarity, theprocess can be applied for both micromachining and micro-deposition. It can be extended formachining and or deposition of wide range of materials.

  17. Microhollow cathode discharges

    Science.gov (United States)

    Schoenbach, K. H.; Moselhy, M.; Shi, W.; Bentley, R.

    2003-07-01

    By reducing the dimensions of hollow cathodes into the hundred micrometer range, stable, direct current, high (atmospheric) pressure glow discharges in rare gases, rare gas-halide mixtures and in air could be generated. The electron energy distribution in these microdischarges is non-Maxwellian, with a pronounced high-energy tail. The high electron energy together with the high gas density, which favors three-body collisions, is the reason for an efficient excimer generation in these microplasmas. Excimer efficiencies from 1% to 9% have been measured for argon, xenon, argon fluoride, and xenon chloride direct current excimer emitters, with a radiant excimer emittance of up to 2 W/cm2 for xenon. Adding small amounts of oxygen to argon has allowed us to generate vacuum ultraviolet line radiation at 130.5 nm with an efficiency approaching 1%. Pulsing xenon discharges with nanosecond electrical pulses has led to an increase in intensity to 15 W/cm2 and to a simultaneous increase in efficiency to more than 20%. Operating the discharges in an abnormal glow mode has allowed us to generate microdischarge arrays without individual ballast. Applications of these plasma arrays are excimer lamps and plasma reactors.

  18. Modeling electronegative plasma discharge

    Energy Technology Data Exchange (ETDEWEB)

    Lichtenberg, A.J.; Lieberman, M.A. [Univ. of California, Berkley, CA (United States)

    1995-12-31

    Macroscopic analytic models for a three-component electronegative gas discharge are developed. Assuming the negative ions to be in Boltzmann equilibrium, a positive ion ambipolar diffusion equation is derived. The discharge consists of an electronegative core and electropositive edges. The electron density in the core is nearly uniform, allowing a parabolic approximation to the plasma profile to be employed. The resulting equilibrium equations are solved analytically and matched to a constant mobility transport model of an electropositive edge plasma. The solutions are compared to a simulation of a parallel-plane r.f. driven oxygen plasma for p = 50 mTorr and n{sub eo}= 2.4 x 10{sup 15} m{sup -3}. The ratio {alpha}{sub o} of central negative ion density to electron density, and the electron temperature T{sub e}, found in the simulation, are in reasonable agreement with the values calculated from the model. The model is extended to: (1) low pressures, where a variable mobility model is used in the electropositive edge region; and (2) high {alpha}{sub o} in which the edge region disappears. The inclusion of a second positive ion species, which can be very important in describing electronegative discharges used for materials processing, is a possible extension of the model.

  19. Spleen removal - open - adults - discharge

    Science.gov (United States)

    Splenectomy - adult - discharge; Spleen removal - adult - discharge ... You had surgery to remove your spleen. This operation is called splenectomy . The surgeon made a cut (incision) in the middle of your belly or on the left side ...

  20. Theory of gas discharge plasma

    CERN Document Server

    Smirnov, Boris M

    2015-01-01

    This book presents the theory of gas discharge plasmas in a didactical way. It explains the processes in gas discharge plasmas. A gas discharge plasma is an ionized gas which is supported by an external electric field. Therefore its parameters are determined by processes in it. The properties of a gas discharge plasma depend on its gas component, types of external fields, their geometry and regimes of gas discharge. Fundamentals of a gas discharge plasma include elementary, radiative and transport processes which are included in its kinetics influence. They are represented in this book together with the analysis of simple gas discharges. These general principles are applied to stationary gas discharge plasmas of helium and argon. The analysis of such plasmas under certain conditions is theoretically determined by numerical plasma parameters for given regimes and conditions.

  1. Re-appraisal and extension of the Gratton-Vargas two-dimensional analytical snowplow model of plasma focus. III. Scaling theory for high pressure operation and its implications

    Science.gov (United States)

    Auluck, S. K. H.

    2016-12-01

    Recent work on the revised Gratton-Vargas model (Auluck, Phys. Plasmas 20, 112501 (2013); 22, 112509 (2015) and references therein) has demonstrated that there are some aspects of Dense Plasma Focus (DPF), which are not sensitive to details of plasma dynamics and are well captured in an oversimplified model assumption, which contains very little plasma physics. A hyperbolic conservation law formulation of DPF physics reveals the existence of a velocity threshold related to specific energy of dissociation and ionization, above which, the work done during shock propagation is adequate to ensure dissociation and ionization of the gas being ingested. These developments are utilized to formulate an algorithmic definition of DPF optimization that is valid in a wide range of applications, not limited to neutron emission. This involves determination of a set of DPF parameters, without performing iterative model calculations, that lead to transfer of all the energy from the capacitor bank to the plasma at the time of current derivative singularity and conversion of a preset fraction of this energy into magnetic energy, while ensuring that electromagnetic work done during propagation of the plasma remains adequate for dissociation and ionization of neutral gas being ingested. Such a universal optimization criterion is expected to facilitate progress in new areas of DPF research that include production of short lived radioisotopes of possible use in medical diagnostics, generation of fusion energy from aneutronic fuels, and applications in nanotechnology, radiation biology, and materials science. These phenomena are expected to be optimized for fill gases of different kinds and in different ranges of mass density compared to the devices constructed for neutron production using empirical thumb rules. A universal scaling theory of DPF design optimization is proposed and illustrated for designing devices working at one or two orders higher pressure of deuterium than the current

  2. Plasma Discharge Process in a Pulsed Diaphragm Discharge System

    Science.gov (United States)

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

    2014-12-01

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

  3. Compact Intracloud Discharges

    Energy Technology Data Exchange (ETDEWEB)

    Smith, David A. [Univ. of Colorado, Boulder, CO (United States)

    1998-11-01

    In November of 1993, mysterious signals recorded by a satellite-borne broadband VHF radio science experiment called Blackboard led to a completely unexpected discovery. Prior to launch of the ALEXIS satellite, it was thought that its secondary payload, Blackboard, would most often detect the radio emissions from lightning when its receiver was not overwhelmed by noise from narrowband communication carriers. Instead, the vast majority of events that triggered the instrument were isolated pairs of pulses that were one hundred times more energetic than normal thunderstorm electrical emissions. The events, which came to be known as TIPPs (for transionospheric pulse pairs), presented a true mystery to the geophysics community. At the time, it was not even known whether the events had natural or anthropogenic origins. After two and one half years of research into the unique signals, two ground-based receiver arrays in New Mexico first began to detect and record thunderstorm radio emissions that were consistent with the Blackboard observations. On two occasions, the ground-based systems and Blackboard even recorded emissions that were produced by the same exact events. From the ground based observations, it has been determined that TIPP events areproduced by brief, singular, isolated, intracloud electrical discharges that occur in intense regions of thunderstorms. These discharges have been dubbed CIDS, an acronym for compact intracloud discharges. During the summer of 1996, ground-based receiver arrays were used to record the electric field change signals and broadband HF emissions from hundreds of CIDS. Event timing that was accurate to within a few microseconds made possible the determination of source locations using methods of differential time of arrival. Ionospheric reflections of signals were recorded in addition to groundwave/line-of-sight signals and were used to determine accurate altitudes for the discharges. Twenty-four CIDS were recorded from three

  4. Continuous pile discharging machine

    Science.gov (United States)

    Smith, Phillips P.

    1976-05-11

    A device for discharging cartridges from tubes under fluid pressure includes a cylindrical housing adapted to be seated in a leak-tight manner on the end of one of the tubes, a chute depending from the cylindrical housing near the end seated on the end of the tube, a rotatable piston having a wrench on the forward end thereof disposed in the cylindrical housing and adapted to manipulate a plug in the end of the tube, and a telescopic hydraulic ram adapted to move the piston toward the plug. In addition the wrench contains a magnet which prevents inadvertent uncoupling of the wrench and the plug.

  5. Experimental studies of radiation resistance of boron nitride, C2C ceramics Al2O3 and carbon-fiber composites using a PF-1000 plasma-focus device

    Science.gov (United States)

    Gribkov, V. A.; Tuniz, C.; Demina, E. V.; Dubrovsky, A. V.; Pimenov, V. N.; Maslyaev, S. V.; Gaffka, R.; Gryaznevich, M.; Skladnik-Sadowska, E.; Sadowski, M. J.; Miklaszewski, R.; Paduch, M.; Scholz, M.

    2011-04-01

    This paper reports on experiments undertaken to compare the radiation resistance of two types of ceramics, boron nitride (BN) and pure alumina (Al2O3), which are used in a TAEA antenna coil installed in the MAST spherical tokamak. Samples of the investigated materials (bulk BN and a 20 μm film of Al2O3 on Al substrate) were exposed on the axis of the plasma-focus PF-1000 device, which can emit intense streams of hot plasma (v≈107 cm s-1 and Npl≈1018 cm-3) and fast deuteron beams (Ei≈100 keV). The most powerful plasma-ion pulse lasted 0.2-1.0 μs and its intensity decayed in about 100 μs. The irradiation process was diagnosed using fast optical cameras, laser interferometry and optical spectrometry. Experiments were performed at power flux densities equal to 109-1010 W cm-2 or 108-109 W cm-2 during the most powerful stage of the interaction process. The irradiated specimens were investigated by means of optical microscopy and x-ray structure analysis (XRSA). It was shown that at 1010 W cm-2 pulses the Al2O3 coating was completely evaporated, whereas a surface of the BN sample became smoother than in the virgin one. A direct comparison of both samples after the action of 108 W cm-2 pulses demonstrated a wave-like structure (more distinct on Al2O3). Weighing of these samples showed, however, that the evaporation of BN was about two times stronger than that of Al2O3 in spite of the lower irradiation flux; the XRSA showed no evidence of cracking of Al2O3 after these pulses. The insulation properties of Al2O3 did not decline, and the Al2O3 coating may be potentially more beneficial, provided that it is kept below its melting point. Characteristic features of damages of a material based on the carbon-fiber composite with additions of silicium carbide (SiC; 8-40% volumetric) were also investigated. It was found that at q=109 W cm-2, the surface erosion is associated with sputtering and evaporation. The degree of this erosion depends on the fibers' orientation in

  6. Experimental studies of radiation resistance of boron nitride, C2C ceramics Al{sub 2}O{sub 3} and carbon-fiber composites using a PF-1000 plasma-focus device

    Energy Technology Data Exchange (ETDEWEB)

    Gribkov, V A; Demina, E V; Dubrovsky, A V; Pimenov, V N; Maslyaev, S V [Laboratory for Radiation Interaction with Metals, A A Baikov Institute of Metallurgy and Material Science, 119991 Moscow (Russian Federation); Tuniz, C [Multidisciplinary Laboratory, Abdus Salam International Centre for Theoretical Physics, 34014 Trieste (Italy); Gaffka, R; Gryaznevich, M [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Skladnik-Sadowska, E; Sadowski, M J [Andrzej Soltan Institute for Nuclear Studies, 05-400 Otwock-Swierk n. Warsaw (Poland); Miklaszewski, R; Paduch, M; Scholz, M, E-mail: gribkovv@yahoo.com [Dense Magnetized Plasma Division, Institute of Plasma Physics and Laser Microfusion, 01-497 Warsaw (Poland)

    2011-04-15

    This paper reports on experiments undertaken to compare the radiation resistance of two types of ceramics, boron nitride (BN) and pure alumina (Al{sub 2}O{sub 3}), which are used in a TAEA antenna coil installed in the MAST spherical tokamak. Samples of the investigated materials (bulk BN and a 20 {mu}m film of Al{sub 2}O{sub 3} on Al substrate) were exposed on the axis of the plasma-focus PF-1000 device, which can emit intense streams of hot plasma (v{approx}10{sup 7} cm s{sup -1} and N{sub pl}{approx}10{sup 18} cm{sup -3}) and fast deuteron beams (E{sub i}{approx}100 keV). The most powerful plasma-ion pulse lasted 0.2-1.0 {mu}s and its intensity decayed in about 100 {mu}s. The irradiation process was diagnosed using fast optical cameras, laser interferometry and optical spectrometry. Experiments were performed at power flux densities equal to 10{sup 9}-10{sup 10} W cm{sup -2} or 10{sup 8}-10{sup 9} W cm{sup -2} during the most powerful stage of the interaction process. The irradiated specimens were investigated by means of optical microscopy and x-ray structure analysis (XRSA). It was shown that at 10{sup 10} W cm{sup -2} pulses the Al{sub 2}O{sub 3} coating was completely evaporated, whereas a surface of the BN sample became smoother than in the virgin one. A direct comparison of both samples after the action of 10{sup 8} W cm{sup -2} pulses demonstrated a wave-like structure (more distinct on Al{sub 2}O{sub 3}). Weighing of these samples showed, however, that the evaporation of BN was about two times stronger than that of Al{sub 2}O{sub 3} in spite of the lower irradiation flux; the XRSA showed no evidence of cracking of Al{sub 2}O{sub 3} after these pulses. The insulation properties of Al{sub 2}O{sub 3} did not decline, and the Al{sub 2}O{sub 3} coating may be potentially more beneficial, provided that it is kept below its melting point. Characteristic features of damages of a material based on the carbon-fiber composite with additions of silicium carbide (Si

  7. Electrosurgical Plasma Discharges

    Science.gov (United States)

    Stalder, K. R.; Woloszko, J.

    2002-10-01

    Electrosurgical instruments employing plasmas to volumetrically ablate tissue are now enjoying widespread use in medical applications. We have studied several commercially available instruments in which luminous plasma discharges are formed near electrodes immersed in saline solutions when sufficiently large amplitude bipolar voltage waveforms are applied. Different aqueous salt solutions have been investigated, including isotonic NaCl solution as well as solutions of KCl, and BaCl_2. With strong driving voltage applied, a vapor layer is formed as well as visible and UV optical emissions. Spectroscopic measurements reveal the predominant emissions are from the low ionization potential salt species, but significant emissions from electron impact dissociated water fragments such as OH and H-atoms also are observed. The emissions also coincide with negative bias on the active electrode. These optical emissions are consistent with an electron density of about 10^12cm-3 and an electron temperature of about 4 eV. Experimental results and model calculations of the vapor layer formation process and plasma formation in the high-field region will be discussed.

  8. YANGTZE DISCHARGE MEMORY

    Institute of Scientific and Technical Information of China (English)

    Klaus Fraedrich; Xiuhua Zhu

    2009-01-01

    We present a review on studies focusing on memories in hydrological time series in the Yangtze Basin based on observational and reconstructed historical data.Memory appears as scaling of power spectra,S(f)~f-β,with 0 <β≤ 1.The presence of scaling is noteworthy in daily river discharge time series:1)from weeks to a couple of years,power spectra follow flicker noise,that is β≈ 1;2)beyond years,spectral scaling appraaclTes β≈0.3.In historical time series of floods and draughts,power spectra also shows scaling with β≈ 0.38 ~0.52.Furthermore,a 70-year peak is detected in historical maritime events series,which also appears in other past climate indicators.Presence of memory in these hydrological time series implies clustering of extremes and scaling of their recurrence times,therefore,probabilistic forecast potential for extremes can be derived.On the other hand,although several physical processes,for example,soil moisture storage and high intermittency of precipitation,have been suggested to be the possible candidates contributing to the presence of long term memory,they remain open for future research.

  9. Modelling Discharge Inception in Thunderstorms

    NARCIS (Netherlands)

    Rutjes, Casper; Dubinova, Anna; Ebert, Ute; Buitink, Stijn; Scholten, Olaf; Trinh, Gia Thi Ngoc

    2015-01-01

    The electric fields in thunderstorms can exceed the breakdown value locally near hydrometeors. But are fields high enough and the regions large enough to initiate a streamer discharge? And where would a sufficient density of free electrons come from to start the discharge in the humid air that rapid

  10. [Redesigning the hospital discharge process].

    Science.gov (United States)

    Martínez-Ramos, M; Flores-Pardo, E; Uris-Sellés, J

    2016-01-01

    The aim of this article is to show that the redesign and planning process of hospital discharge advances the departure time of the patient from a hospital environment. Quasi-experimental study conducted from January 2011 to April 2013, in a local hospital. The cases analysed were from medical and surgical nursing units. The process was redesigned to coordinate all the professionals involved in the process. The hospital discharge improvement process improvement was carried out by forming a working group, the analysis of retrospective data, identifying areas for improvement, and its redesign. The dependent variable was the time of patient administrative discharge. The sample was classified as pre-intervention, inter-intervention, and post-intervention, depending on the time point of the study. The final sample included 14,788 patients after applying the inclusion and exclusion criteria. The mean discharge release time decreased significantly by 50 min between pre-intervention and post-intervention periods. The release time in patients with planned discharge was one hour and 25 min less than in patients with unplanned discharge. Process redesign is a useful strategy to improve the process of hospital discharge. Besides planning the discharge, it is shown that the patient leaving the hospital before 12 midday is a key factor. Copyright © 2015 SECA. Published by Elsevier Espana. All rights reserved.

  11. The practice of terminal discharge.

    Science.gov (United States)

    Radha Krishna, Lalit Kumar; Murugam, Vengadasalam; Quah, Daniel Song Chiek

    2017-01-01

    'Terminal discharges' are carried out in Singapore for patients who wish to die at home. However, if due diligence is not exercised, parallels may be drawn with euthanasia. We present a theoretical discussion beginning with the definition of terminal discharges and the reasons why they are carried out in Singapore. By considering the intention behind terminal discharges and utilising a multidisciplinary team to deliberate on the clinical, social and ethical intricacies with a patient- and context-specific approach, euthanasia is avoided. It is hoped that this will provide a platform for professionals in palliative medicine to negotiate challenging issues when arranging a terminal discharge, so as to avoid the pitfall of committing euthanasia in a country such as Singapore where euthanasia is illegal. It is hoped that a set of guidelines for terminal discharges may someday be realised to assist professionals in Singapore and around the world.

  12. Discharge Planning in Chronic Conditions

    Science.gov (United States)

    McMartin, K

    2013-01-01

    Background Chronically ill people experience frequent changes in health status accompanied by multiple transitions between care settings and care providers. Discharge planning provides support services, follow-up activities, and other interventions that span pre-hospital discharge to post-hospital settings. Objective To determine if discharge planning is effective at reducing health resource utilization and improving patient outcomes compared with standard care alone. Data Sources A standard systematic literature search was conducted for studies published from January 1, 2004, until December 13, 2011. Review Methods Reports, randomized controlled trials, systematic reviews, and meta-analyses with 1 month or more of follow-up and limited to specified chronic conditions were examined. Outcomes included mortality/survival, readmissions and emergency department (ED) visits, hospital length of stay (LOS), health-related quality of life (HRQOL), and patient satisfaction. Results One meta-analysis compared individualized discharge planning to usual care and found a significant reduction in readmissions favouring individualized discharge planning. A second meta-analysis compared comprehensive discharge planning with postdischarge support to usual care. There was a significant reduction in readmissions favouring discharge planning with postdischarge support. However, there was significant statistical heterogeneity. For both meta-analyses there was a nonsignificant reduction in mortality between the study arms. Limitations There was difficulty in distinguishing the relative contribution of each element within the terms “discharge planning” and “postdischarge support.” For most studies, “usual care” was not explicitly described. Conclusions Compared with usual care, there was moderate quality evidence that individualized discharge planning is more effective at reducing readmissions or hospital LOS but not mortality, and very low quality evidence that it is more

  13. NPDES (National Pollution Discharge & Elimination System) Minor Dischargers

    Data.gov (United States)

    U.S. Environmental Protection Agency — As authorized by the Clean Water Act, the National Pollutant Discharge Elimination System (NPDES) permit program controls water pollution by regulating point sources...

  14. HIGH ENERGY GASEOUS DISCHARGE DEVICES

    Science.gov (United States)

    Josephson, V.

    1960-02-16

    The high-energy electrical discharge device described comprises an envelope, a pair of main discharge electrodes supported in opposition in the envelope, and a metallic shell symmetrically disposed around and spaced from the discharge path between the electrodes. The metallic shell comprises a first element of spaced helical turns of metallic material and a second element of spaced helical turns of methllic material insulatedly supported in superposition outside the first element and with the turns overlapping the gap between the turns of the first element.

  15. An introduction to gas discharges

    CERN Document Server

    Howatson, A M

    2013-01-01

    An Introduction to Gas Discharges: Second Edition aims to provide a compact introduction to the subject of gas discharges, which continues to make both scientific and industrial progress. In this second edition, the author has made minor corrections, rewritten and expanded some sections, used SI units and modernized notions, in hopes of making the book more up to date. Included in the book is a short history of the subject, an introduction that enumerates the types of gas discharges, the fundamental processes, and then moves on to the more specific areas such as the breakdown, the self-sustai

  16. Snowfall induced by corona discharge

    CERN Document Server

    Ju, Jingjing; Li, Ruxin; Du, Shengzhe; Sun, Haiyi; Liu, Yonghong; Tian, Ye; Bai, Yafeng; Liu, Yaoxiang; Chen, Na; Wang, Jingwei; Wang, Cheng; Liu, Jiansheng; Chin, S L; Xu, Zhizhan

    2016-01-01

    We demonstrated for the first time the condensation and precipitation (or snowfall) induced by a corona discharge inside a cloud chamber. Ionic wind was found to have played a more significant role than ions as extra Cloud Condensation Nuclei (CCN). 2.25 g of net snow enhancement was measured after applying a 30 kV corona discharge for 25 min. In comparison with another newly emerging femtosecond laser filamentation method, the snow precipitation induced by the corona discharge has about 4 orders of magnitude higher wall-plug efficiency under similar conditions.

  17. Research on the Optical Properties of Transformers Partial Discharge Based on Different Discharge Models

    Directory of Open Access Journals (Sweden)

    Wei Bengang

    2016-01-01

    Full Text Available In this paper, the different types of discharge in transformer were simulated based on the real transformer fault model. The optical partial discharge detection system was established based on optical sensors which were capturing partial discharge accompanied by optical effects. In this research, surface discharge and suspended discharge defect model was pressurized to generate partial discharge signal. The results showed that: Partial discharge optical signals could effectively respond the production and development process of transformer partial discharge. It was able to assess discharge level also. When the discharge phenomenon stabilized, the phase of surface discharge mainly between 60°~150°and 240°~330°, the phase of suspended discharge mainly between 260°~320°. According to the phase characteristic of discharge pattern, the creeping discharge and suspended discharge phenomenon of transformer can be distinguished. It laid the foundation for the application of transformer optical partial discharge detection technology.

  18. Pulsed discharge production Ar* metastables

    Science.gov (United States)

    Han, Jiande; Heaven, Michael C.; Emmons, Daniel; Perram, Glen P.; Weeks, David E.; Bailey, William F.

    2016-03-01

    The production of relatively high densities of Ar* metastables (>1012 cm-3) in Ar/He mixtures, at total pressures close to 1 atm, is essential for the efficient operation of an optically pumped Ar* laser. We have used emission spectroscopy and diode laser absorption spectroscopy measurements to observe the production and decay of Ar* in a parallel plate pulsed discharge. With discharge pulses of 1 μs duration we find that metastable production is dominated by processes occurring within the first 100 ns of the gas break-down. Application of multiple, closely spaced discharge pulses yields insights concerning conditions that favor metastable production. This information has been combined with time-resolved measurements of voltage and current. The experimental results and preliminary modeling of the discharge kinetics are presented.

  19. Circle Points Discharge Tube Current Controller

    Institute of Scientific and Technical Information of China (English)

    Meng Jinjia; Meng Lisheng

    2005-01-01

    Circle points discharge tube current controller is a new type device to limit theoutput of high voltage discharge current. Circle points uniform corona discharge to form airionization current in the discharge tube. On the outside, even if the discharge electrode is sparkdischarging or the two discharge electrodes are short circuited, the air ionization current in the tuberemains within a stable range, and there is no spark discharge. In this case, when the dischargecurrent only increases slightly, the requirement to limited current is obtained. By installing thecontroller at a discharge pole with a small power but high voltage supply, we can realize the shiftbetween the continuous spark line discharge and corona discharge. This provides a new simpledevice for spark discharge research and is a supplement to the Townsend discharge experiment.

  20. Study on the transition from filamentary discharge to diffuse discharge by using a dielectric barrier surface discharge device

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Discharge characteristics have been investigated in different gases under different pressures using a dielectric barrier surface discharge device. Electrical measurements and optical emission spectroscopy are used to study the discharge,and the results obtained show that the discharges in atmospheric pressure helium and in low-pressure air are diffuse,while that in high-pressure air is filamentary. With decreasing pressure, the discharge in air can transit from filamentary to diffuse one. The results also indicate that corona discharge around the stripe electrode is important for the diffuse discharge. The spectral intensity of N2+ (391.4 nm) relative to N2 (337.1 nm) is measured during the transition from diffuse to filamentary discharge. It is shown that relative spectral intensity increases during the discharge transition. This phenomenon implies that the averaged electron energy in diffuse discharge is higher than that in the filamentary discharge.

  1. Classification of electrical discharges in DC Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Srutarshi, E-mail: sruban.stephens@gmail.com [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Deb, A.K. [Department of Electrical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India); Rajan, Rehim N. [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Kishore, N.K. [Department of Electrical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)

    2016-08-11

    Controlled electrical discharge aids in conditioning of the system while uncontrolled discharges damage its electronic components. DC Accelerator being a high voltage system is no exception. It is useful to classify electrical discharges according to the severity. Experimental prototypes of the accelerator discharges are developed. Photomultiplier Tubes (PMTs) are used to detect the signals from these discharges. Time and Frequency domain characteristics of the detected discharges are used to extract features. Machine Learning approaches like Fuzzy Logic, Neural Network and Least Squares Support Vector Machine (LSSVM) are employed to classify the discharges. This aids in detecting the severity of the discharges.

  2. Classification of electrical discharges in DC Accelerators

    Science.gov (United States)

    Banerjee, Srutarshi; Deb, A. K.; Rajan, Rehim N.; Kishore, N. K.

    2016-08-01

    Controlled electrical discharge aids in conditioning of the system while uncontrolled discharges damage its electronic components. DC Accelerator being a high voltage system is no exception. It is useful to classify electrical discharges according to the severity. Experimental prototypes of the accelerator discharges are developed. Photomultiplier Tubes (PMTs) are used to detect the signals from these discharges. Time and Frequency domain characteristics of the detected discharges are used to extract features. Machine Learning approaches like Fuzzy Logic, Neural Network and Least Squares Support Vector Machine (LSSVM) are employed to classify the discharges. This aids in detecting the severity of the discharges.

  3. Microhollow Cathode Discharge Excimer Lamps

    Science.gov (United States)

    Schoenbach, K. H.

    1999-11-01

    character. Reducing the diameter of the cathode hole in a hollow cathode discharge geometry to values on the order of 100 μm has allowed us to extend the pressure range of stable, direct current hollow cathode gas discharges up to atmospheric pressure. The large concentration of high-energy electrons generated in the cathode fall, in combination with the high neutral gas density favors three-body processes such as excimer formation. Excimer emission in xenon discharges peaking at 172 nm, was observed with efficiencies between 6% and 9% at pressures of several hundred Torr. Typical forward voltages are 200 V at dc currents up to 8 mA. Pulsed operation allowed us to extend the current range to 80 mA with corresponding linear increase in optical power. Spatially resolved measurements showed that the source of the excimer radiation at atmospheric pressure and currents of less than 8 mA is confined to the cathode opening. The radiative emittance at 8 mA and atmospheric pressure is approximately 20 W/cm^2. With reduced pressure and increased current, respectively, the excimer source extends into the area outside the cathode hole. Besides in xenon, excimer emission in argon at a peak wavelength of 128 nm has been recorded. In addition to operating the discharge in rare gases, we have also explored its use as rare gas-halide excimer source. In a gas mixture containing 1% ArF we were able to generate stable dc discharges in flowing gas at pressures ranging from 100 Torr to atmospheric pressure. The spectra of the high-pressure ArF discharges are dominated by excimer radiation peaking at 193 nm. The excimer emission of a single ArF discharge at 700 Torr was measured as 150 mW at an efficiency of 3%. Parallel operation of these discharges by means of a resistive anode, which has recently been demonstrated for argon discharges, offers the possibility to use microhollow cathode discharge arrays as dc-excimer lamps, with estimated power densities exceeding 10 W/cm^2. abstract

  4. Water purification by electrical discharges

    Science.gov (United States)

    Arif Malik, Muhammad; Ghaffar, Abdul; Akbar Malik, Salman

    2001-02-01

    There is a continuing need for the development of effective, cheap and environmentally friendly processes for the disinfection and degradation of organic pollutants from water. Ozonation processes are now replacing conventional chlorination processes because ozone is a stronger oxidizing agent and a more effective disinfectant without any side effects. However, the fact that the cost of ozonation processes is higher than chlorination processes is their main disadvantage. In this paper recent developments targeted to make ozonation processes cheaper by improving the efficiency of ozone generation, for example, by incorporation of catalytic packing in the ozone generator, better dispersion of ozone in water and faster conversion of dissolved ozone to free radicals are described. The synthesis of ozone in electrical discharges is discussed. Furthermore, the generation and plasma chemical reactions of several chemically active species, such as H2O2, Obullet, OHbullet, HO2bullet, O3*, N2*, e-, O2-, O-, O2+, etc, which are produced in the electrical discharges are described. Most of these species are stronger oxidizers than ozone. Therefore, water treatment by direct electrical discharges may provide a means to utilize these species in addition to ozone. Much research and development activity has been devoted to achieve these targets in the recent past. An overview of these techniques and important developments that have taken place in this area are discussed. In particular, pulsed corona discharge, dielectric barrier discharge and contact glow discharge electrolysis techniques are being studied for the purpose of cleaning water. The units based on electrical discharges in water or close to the water level are being tested at industrial-scale water treatment plants.}

  5. Helicon plasma thruster discharge model

    Energy Technology Data Exchange (ETDEWEB)

    Lafleur, T., E-mail: trevor.lafleur@lpp.polytechnique.fr [Laboratoire de Physique des Plasmas, CNRS, Sorbonne Universités, UPMC Univ Paris 06, Univ Paris-Sud, Ecole Polytechnique, 91128 Palaiseau, France and ONERA - The French Aerospace Lab, 91120 Palaiseau (France)

    2014-04-15

    By considering particle, momentum, and energy balance equations, we develop a semi-empirical quasi one-dimensional analytical discharge model of radio-frequency and helicon plasma thrusters. The model, which includes both the upstream plasma source region as well as the downstream diverging magnetic nozzle region, is compared with experimental measurements and confirms current performance levels. Analysis of the discharge model identifies plasma power losses on the radial and back wall of the thruster as the major performance reduction factors. These losses serve as sinks for the input power which do not contribute to the thrust, and which reduce the maximum plasma density and hence propellant utilization. With significant radial plasma losses eliminated, the discharge model (with argon) predicts specific impulses in excess of 3000 s, propellant utilizations above 90%, and thruster efficiencies of about 30%.

  6. Capillary Discharge XUV Radiation Source

    Directory of Open Access Journals (Sweden)

    M. Nevrkla

    2009-01-01

    Full Text Available A device producing Z-pinching plasma as a source of XUV radiation is described. Here a ceramic capacitor bank pulse-charged up to 100 kV is discharged through a pre-ionized gas-filled ceramic tube 3.2 mm in diameter and 21 cm in length. The discharge current has amplitude of 20 kA and a rise-time of 65 ns. The apparatus will serve as experimental device for studying of capillary discharge plasma, for testing X-ray optics elements and for investigating the interaction of water-window radiation with biological samples. After optimization it will be able to produce 46.9 nm laser radiation with collision pumped Ne-like argon ions active medium. 

  7. Stroke rehabilitation and discharge planning.

    Science.gov (United States)

    Kerr, Peter

    Nurses play a pivotal role in the rehabilitation and discharge planning process of patients who have had a stroke. The nurse's role in the wider stroke multidisciplinary team is complex and diverse and, as such, stroke nurses may find it hard to describe their role and how it fits into the rehabilitation and discharge planning process. A definition of the stroke nurse role in prominent publications such as those of the Scottish Intercollegiate Guidelines Network and the Royal College of Physicians is lacking. This article emphasises the role of the stroke nurse in the rehabilitation and discharge planning process in the stroke unit, while highlighting the complexity, diversity and importance of this role in providing holistic care and support for patients who have survived a stroke. The author draws on his clinical experience of stroke nursing practice in primary, secondary and tertiary care in west central Scotland.

  8. State Waste Discharge Permit application, 183-N Backwash Discharge Pond

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    As part of the Hanford Federal Facility Agreement and Consent Order negotiations (Ecology et al. 1994), the US Department of Energy, Richland Operations Office, the US Environmental Protection Agency, and the Washington State Department of Ecology agreed that liquid effluent discharges to the ground on the Hanford Site which affect groundwater or have the potential to affect groundwater would be subject to permitting under the structure of Chapter 173--216 (or 173--218 where applicable) of the Washington Administrative Code, the State Waste Discharge Permit Program. As a result of this decision, the Washington State Department of Ecology and the US Department of Energy, Richland Operations Office entered into Consent Order No. DE91NM-177, (Ecology and DOE-RL 1991). The Consent Order No. DE91NM-177 requires a series of permitting activities for liquid effluent discharges. Liquid effluents on the Hanford Site have been classified as Phase I, Phase II, and Miscellaneous Streams. The Consent Order No. DE91NM-177 establishes milestones for State Waste Discharge Permit application submittals for all Phase I and Phase II streams, as well as the following 11 Miscellaneous Streams as identified in Table 4 of the Consent Order No. DE91NM-177.

  9. Compact monolithic capacitive discharge unit

    Science.gov (United States)

    Roesler, Alexander W.; Vernon, George E.; Hoke, Darren A.; De Marquis, Virginia K.; Harris, Steven M.

    2007-06-26

    A compact monolithic capacitive discharge unit (CDU) is disclosed in which a thyristor switch and a flyback charging circuit are both sandwiched about a ceramic energy storage capacitor. The result is a compact rugged assembly which provides a low-inductance current discharge path. The flyback charging circuit preferably includes a low-temperature co-fired ceramic transformer. The CDU can further include one or more ceramic substrates for enclosing the thyristor switch and for holding various passive components used in the flyback charging circuit. A load such as a detonator can also be attached directly to the CDU.

  10. Dielectric barrier discharges in analytical chemistry.

    Science.gov (United States)

    Meyer, C; Müller, S; Gurevich, E L; Franzke, J

    2011-06-21

    The present review reflects the importance of dielectric barrier discharges in analytical chemistry. Special about this discharge is-and in contrast to usual discharges with direct current-that the plasma is separated from one or two electrodes by a dielectric barrier. This gives rise to two main features of the dielectric barrier discharges; it can serve as dissociation and excitation device and as ionization mechanism, respectively. The article portrays the various application fields for dielectric barrier discharges in analytical chemistry, for example the use for elemental detection with optical spectrometry or as ionization source for mass spectrometry. Besides the introduction of different kinds of dielectric barrier discharges used for analytical chemistry from the literature, a clear and concise classification of dielectric barrier discharges into capacitively coupled discharges is provided followed by an overview about the characteristics of a dielectric barrier discharge concerning discharge properties and the ignition mechanism.

  11. Investigation of electrolyte electric discharge characteristics

    Science.gov (United States)

    Kirko, D. L.; Savjolov, A. S.

    2016-09-01

    The most important electrical characteristics of electrolyte electric discharge were investigated. The electric burning discharge was obtained with the help of different electrolytes. The spectral composition of the electric discharge electromagnetic radiation was determined, the plasma temperature was determined. The spectrum of the electric discharge high-frequency oscillations was calculated in the region v=10 kHz-80 MHz. The most appropriate modes of the electric burning discharge in different electrolytes were proposed.

  12. Electronic Discharge Letter Mobile App

    NARCIS (Netherlands)

    Lezcano, Leonardo; Triana, Michel; Ternier, Stefaan; Hartkopf, Kathleen; Stieger, Lina; Schroeder, Hanna; Sopka, Sasa; Drachsler, Hendrik; Maher, Bridget; Henn, Patrick; Orrego, Carola; Marcus, Specht

    2014-01-01

    The electronic discharge letter mobile app takes advantage of Near Field Communication (NFC) within the PATIENT project and a related post-doc study. NFC enabled phones to read passive RFID tags, but can also use this short-range wireless technology to exchange (small) messages. NFC in that sense co

  13. Plasma Characteristics of Electrosurgical Discharges*

    Science.gov (United States)

    Stalder, Kenneth R.

    2003-10-01

    Surgical devices utilizing electrical discharges of ever increasing sophistication have been used for decades for numerous procedures. Cushing and Bovie in 1928, for example, developed high-frequency spark generators to cauterize blood vessels and remove unwanted tissue by a thermal ablation processes. Modern Bovies (named after their inventor) use a high-frequency discharge from an electrode to nearby tissue to thermally ablate tissue. Spectroscopic analysis shows that these discharges are hot and are well represented by a thermal equilibrium model, and temperatures near 2000 K are easily achieved. New electrosurgical devices utilizing repetitive electrical discharges in a conducting saline environment have recently been developed. Electron emission from an active electrode during certain portions of the voltage waveform causes the formation of a vapor layer surrounding the electrode and the subsequent ionization and dissociation of species in this region. Electron temperatures of approximately 4 eV are achieved during the plasma phase. Water molecules are dissociated into reactive fragments, and the salt species are also excited and ionized in this nonequilibrium plasma. It is thought that the reactive species interact with nearby tissue, causing localized tissue removal (ablation) which surgeons can exploit during surgical procedures. Flowing saline surrounding the plasma region cools untargeted tissue and removes the reaction products. This presentation will focus on experimental results of the plasma conditions and discuss our current efforts to understand the complex reactions of the various plasma species with tissue structures such as collagen. A short clip showing tissue removal will also be shown.

  14. Electrical discharge machining in dentistry.

    Science.gov (United States)

    Van Roekel, N B

    1992-01-01

    A brief history of electrical discharge machining (EDM) is given and the process is discussed. A description of the application of EDM for fabricating precision attachment removable partial dentures, fixed-removable implant prostheses, and titanium-ceramic crowns is presented. The advantages and disadvantages of the EDM process for the dental profession are evaluated. Although expensive, the procedure has merit.

  15. Discharge current distribution in stratified soil under impulse discharge

    Science.gov (United States)

    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.

  16. Microhollow cathode discharge excimer lamps

    Science.gov (United States)

    Schoenbach, Karl H.; El-Habachi, Ahmed; Moselhy, Mohamed M.; Shi, Wenhui; Stark, Robert H.

    2000-05-01

    Microhollow cathode discharges are high-pressure, nonequilibrium gas discharges between a hollow cathode and a planar or hollow anode with electrode dimensions in the 100 μm range. The large concentration of high-energy electrons, in combination with the high-gas density favors excimer formation. Excimer emission was observed in xenon and argon, at wavelengths of 128 and 172 nm, respectively, and in argon fluoride and xenon chloride, at 193 and 308 nm. The radiant emittance of the excimer radiation was found to increase monotonically with pressure. However, due to the decrease in source size with pressure, the efficiency (ratio of excimer radiant power to input electrical power), has for xenon and argon fluoride a maximum at ˜400 Torr. The maximum efficiency is between 6% and 9% for xenon, and ˜2% for argon fluoride.

  17. Current-induced membrane discharge

    CERN Document Server

    Andersen, M B; Mani, A; Bruus, H; Biesheuvel, P M; Bazant, M Z

    2012-01-01

    Possible mechanisms for over-limiting current (OLC) through aqueous ion-exchange membranes (exceeding diffusion limitation) have been debated for half a century. Flows consistent with electro-osmotic instability (EOI) have recently been observed in microfluidic experiments, but the existing theory neglects chemical effects and remains to be quantitatively tested. Here, we show that charge regulation and water self-ionization can lead to OLC by "current-induced membrane discharge" (CIMD), even in the absence of fluid flow. Salt depletion leads to a large electric field which expels water co-ions, causing the membrane to discharge and lose its selectivity. Since salt co-ions and water ions contribute to OLC, CIMD interferes with electrodialysis (salt counter-ion removal) but could be exploited for current-assisted ion exchange and pH control. CIMD also suppresses the extended space charge that leads to EOI, so it should be reconsidered in both models and experiments on OLC.

  18. Current-Induced Membrane Discharge

    DEFF Research Database (Denmark)

    Andersen, Mathias Bækbo; van Soestbergen, M.; Mani, A.;

    2012-01-01

    Possible mechanisms for overlimiting current (OLC) through aqueous ion-exchange membranes (exceeding diffusion limitation) have been debated for half a century. Flows consistent with electro-osmotic instability have recently been observed in microfluidic experiments, but the existing theory...... neglects chemical effects and remains to be quantitatively tested. Here, we show that charge regulation and water self-ionization can lead to OLC by "current-induced membrane discharge'' (CIMD), even in the absence of fluid flow, in ion-exchange membranes much thicker than the local Debye screening length....... Salt depletion leads to a large electric field resulting in a local pH shift within the membrane with the effect that the membrane discharges and loses its ion selectivity. Since salt co-ions, H+ ions, and OH- ions contribute to OLC, CIMD interferes with electrodialysis (salt counterion removal...

  19. [Ductoscopy for pathologic nipple discharge].

    Science.gov (United States)

    Waaijer, Laurien; van Diest, Paul J; van der Pol, Carmen C; Verolme, Berna; Hennink, Annelies; Witkamp, Arjen J

    2013-01-01

    Pathologic nipple discharge is a symptom that frequently causes female patients to visit the outpatient breast clinic. In the vast majority of cases, the symptom is caused by a benign intraductal laesion. The options for diagnosis and treatment have long been limited; surgery was not infrequently the treatment of choice. With the advent of breast ductoscopy, a micro-endoscopic procedure, it is possible to visualise abnormalities in the ductal system. Tissue for histopathological investigation can be retrieved from the duct and the condition can be treated. The patient with nipple discharge is consequently prevented from having to undergo an invasive and fairly 'blindly' executed procedure under general anaesthesia. The miniscule dimensions of the duct in which the technique is carried out pose the greatest challenge to the further development of the ductoscope.

  20. Internal Electrostatic Discharge Monitor - IESDM

    Science.gov (United States)

    Kim, Wousik; Goebel, Dan M.; Jun, Insoo; Garrett, Henry B.

    2011-01-01

    A document discusses an innovation designed to effectively monitor dielectric charging in spacecraft components to measure the potential for discharge in order to prevent damage from internal electrostatic discharge (IESD). High-energy electrons penetrate the structural materials and shielding of a spacecraft and then stop inside dielectrics and keep accumulating. Those deposited charges generate an electric field. If the electric field becomes higher than the breakdown threshold (approx. =2 x 10(exp 5) V/cm), discharge occurs. This monitor measures potentials as a function of dielectric depth. Differentiation of potential with respect to the depth yields electric field. Direct measurement of the depth profile of the potential in a dielectric makes real-time electronic field evaluation possible without simulations. The IESDM has been designed to emulate a multi-layer circuit board, to insert very thin metallic layers between the dielectric layers. The conductors serve as diagnostic monitoring locations to measure the deposited electron-charge and the charge dynamics. Measurement of the time-dependent potential of the metal layers provides information on the amount of charge deposited in the dielectrics and the movement of that charge with time (dynamics).

  1. 42 CFR 32.89 - Discharge.

    Science.gov (United States)

    2010-10-01

    ... PERSONS WITH HANSEN'S DISEASE AND OTHER PERSONS IN EMERGENCIES Persons with Hansen's Disease § 32.89 Discharge. Patients with Hansen's disease will be discharged when, in the opinion of the medical staff of...

  2. EPA Region 1 No Discharge Zones

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset details No Discharge Zones (NDZ) for New England. Boaters may not discharge waste into these areas. Boundaries were determined mostly by Federal...

  3. Capacitor discharges, magnetohydrodynamics, X-rays, ultrasonics

    CERN Document Server

    Früngel, Frank B A

    1965-01-01

    High Speed Pulse Technology, Volume 1: Capacitor Discharges - Magnetohydrodynamics - X-Rays - Ultrasonics deals with the theoretical and engineering problems that arise in the capacitor discharge technique.This book discusses the characteristics of dielectric material, symmetrical switch tubes with mercury filling, and compensation conductor forms. The transformed discharge for highest current peaks, ignition transformer for internal combustion engines, and X-ray irradiation of subjects in mechanical motion are also elaborated. This text likewise covers the transformed capacitor discharge in w

  4. Modeling High Pressure Micro Hollow Cathode Discharges

    Science.gov (United States)

    2007-11-02

    cathode discharge excimer lamps , Phys. Plasmas 7, 286 (2000). [3] RH Stark and KH Schoenbach, Direct high pressure glow discharges, J. Appl. Phys...temperature profiles in argon glow discharges, J. Appl. Phys. 88, 2234 (2000) [8] M. Moselhy, W. Shi, R. Stark, A flat glow discharge excimer radiation...MHCD acts as a plasma cathode for a third electrode (anode). Some experimental results in this geometry are available for argon and for air from the

  5. Dielectric barrier discharges applied for optical spectrometry

    Science.gov (United States)

    Brandt, S.; Schütz, A.; Klute, F. D.; Kratzer, J.; Franzke, J.

    2016-09-01

    The present review reflects the importance of dielectric barrier discharges for optical spectrometric detection in analytical chemistry. In contrast to usual discharges with a direct current the electrodes are separated by at least one dielectric barrier. There are two main features of the dielectric barrier discharges: they can serve as dissociation and excitation devices as well as ionization sources, respectively. This article portrays various application fields of dielectric barrier discharges in analytical chemistry used for elemental and molecular detection with optical spectrometry.

  6. Early discharge hospital at home.

    Science.gov (United States)

    Gonçalves-Bradley, Daniela C; Iliffe, Steve; Doll, Helen A; Broad, Joanna; Gladman, John; Langhorne, Peter; Richards, Suzanne H; Shepperd, Sasha

    2017-06-26

    Early discharge hospital at home is a service that provides active treatment by healthcare professionals in the patient's home for a condition that otherwise would require acute hospital inpatient care. This is an update of a Cochrane review. To determine the effectiveness and cost of managing patients with early discharge hospital at home compared with inpatient hospital care. We searched the following databases to 9 January 2017: the Cochrane Effective Practice and Organisation of Care Group (EPOC) register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, and EconLit. We searched clinical trials registries. Randomised trials comparing early discharge hospital at home with acute hospital inpatient care for adults. We excluded obstetric, paediatric and mental health hospital at home schemes.   DATA COLLECTION AND ANALYSIS: We followed the standard methodological procedures expected by Cochrane and EPOC. We used the GRADE approach to assess the certainty of the body of evidence for the most important outcomes. We included 32 trials (N = 4746), six of them new for this update, mainly conducted in high-income countries. We judged most of the studies to have a low or unclear risk of bias. The intervention was delivered by hospital outreach services (17 trials), community-based services (11 trials), and was co-ordinated by a hospital-based stroke team or physician in conjunction with community-based services in four trials.Studies recruiting people recovering from strokeEarly discharge hospital at home probably makes little or no difference to mortality at three to six months (risk ratio (RR) 0.92, 95% confidence interval (CI) 0.57 to 1.48, N = 1114, 11 trials, moderate-certainty evidence) and may make little or no difference to the risk of hospital readmission (RR 1.09, 95% CI 0.71 to 1.66, N = 345, 5 trials, low-certainty evidence). Hospital at home may lower the risk of living in institutional setting at six months (RR 0.63, 96% CI

  7. A General Thermal Equilibrium Discharge Flow Model

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Min-fu; ZHANG; Dong-xu; LV; Yu-feng

    2015-01-01

    In isentropic and thermal equilibrium assumptions,a discharge flow model was derived,which unified the rules of normal temperature water discharge,high temperature and high pressure water discharge,two-phase critical flow,saturated steam and superheated steam critical

  8. 32 CFR 724.117 - Discharge review.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false Discharge review. 724.117 Section 724.117 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL NAVAL DISCHARGE REVIEW BOARD Definitions § 724.117 Discharge review. A nonadversary administrative reappraisal at the level...

  9. Continuous optical discharge in a laser cavity

    Science.gov (United States)

    Chivel', Yu. A.

    2016-08-01

    Optical discharge in a laser cavity is experimentally studied. A significant increase in the absorption of laser radiation (up to total absorption) is revealed. Optical schemes for initiation and maintaining of optical discharge in the cavity are proposed for technological applications of the optical discharge.

  10. Predictors of discharge in child psychoanalytic psychotherapy

    OpenAIRE

    Izabel Cristina Paez; Maria Lucia Tiellet Nunes; Vânia Naomi Hirakata

    2015-01-01

    Introduction: This empirical study was based on the analysis of the results of a study about dropout predictors among in child psychoanalytic psychotherapy. The objectives were to characterize the sample of children discharged from psychoanalytic psychotherapy, examine the association between sociodemographic/ clinical variables and child psychoanalytic psychotherapy discharge, and determine predictors of discharge in child psychoanalytic psychotherapy.Method: This quantitative, descriptive a...

  11. Double discharges in unipolar-pulsed dielectric barrier discharge xenon excimer lamps

    Science.gov (United States)

    Liu, Shuhai; Neiger, Manfred

    2003-07-01

    Excitation of dielectric barrier discharge xenon excimer lamps by unipolar short square pulses is studied in this paper. Two discharges with different polarity are excited by each voltage pulse (double discharge phenomenon). The primary discharge occurs at the top or at the rising flank of the applied unipolar square pulse, which is directly energized by the external circuit. The secondary discharge with the reversed polarity occurs at the falling flank or shortly after the falling flank end (zero external voltage) depending on the pulse width, which is energized by the energy stored by memory charges deposited by the primary discharge. Fast-speed ICCD imaging shows the primary discharge has a conic discharge appearance with a channel broadening on the anode side. This channel broadening increases with increasing the pulse top level. Only the anode-side surface discharge is observed in the primary discharge. The surface discharge on the cathode side which is present in bipolar sine voltage excitation is not observed. On the contrary, the secondary discharge has only the cathode-side surface discharge. The surface discharge on the anode side is not observed. The secondary discharge is much more diffuse than the primary discharge. Time-resolved emission measurement of double discharges show the secondary discharge emits more VUV xenon excimer radiation but less infrared (IR) xenon atomic emission than the primary discharge. It was found that the IR xenon atomic emission from the secondary discharge can be reduced by shortening the pulse width. The energy efficiency of unipolar-pulsed xenon excimer lamps (the overall energy efficiency of double discharges) is much higher than that obtained under bipolar sine wave excitation. The output VUV spectrum under unipolar pulse excitation is found to be identical to that under sine wave excitation and independent of injected electric power.

  12. State waste discharge permit application for cooling water and condensate discharges

    Energy Technology Data Exchange (ETDEWEB)

    Haggard, R.D.

    1996-08-12

    The following presents the Categorical State Waste Discharge Permit (SWDP) Application for the Cooling Water and Condensate Discharges on the Hanford Site. This application is intended to cover existing cooling water and condensate discharges as well as similar future discharges meeting the criteria set forth in this document.

  13. Elementary processes in gas discharges

    CERN Document Server

    Bronold, Franz X

    2008-01-01

    This chapter presents, from a quantum-mechanical point of view, a tutorial discussion of elementary collision processes in the bulk of a gas discharge. Instead of merely listing kitchen-made cross section formulae and unrelated cross section data, emphasis has been given on an unified description of elementary processes based on general principles of quantum-mechanical multi-channel scattering theory. By necessity, the presentation is rather dense. Technical details left out, as well as cross section data, can be found, respectively, in the quoted original papers and the review articles, monographs, and web-sites mentioned in the introductory remarks to this chapter.

  14. Interaction between Adjacent Lightning Discharges in Clouds

    Institute of Scientific and Technical Information of China (English)

    WANG Yanhui; ZHANG Guangshu; ZHANG Tong; LI Yajun; WU Bin; ZHANG Tinglong

    2013-01-01

    Using a 3D lightning radiation source locating system (LLS),three pairs of associated lightning discharges (two or more adjacent lightning discharges following an arbitrary rule that their space-gap was less than 10 km and their time-gap was less than 800 ms) were observed,and the interaction between associated lightning discharges was analyzed.All these three pairs of associated lightning discharges were found to involve three or more charge regions (the ground was considered as a special charge region).Moreover,at least one charge region involved two lightning discharges per pair of associated lightning discharges.Identified from electric field changes,the subsequent lightning discharges were suppressed by the prior lightning discharges.However,it is possible that the prior lightning discharge provided a remaining discharge channel to facilitate the subsequent lightning discharge.The third case provided evidence of this possibility.Together,the results suggested that,if the charges in the main negative charge region can be consumed using artificial lightning above the main negative charge regions,lightning accidents on the ground could be greatly reduced,on the condition that the height of the main negative charge region and the charge intensity of the lower positive charge region are suitable.

  15. Electromagnetic fields produced by simulated spacecraft discharges

    Science.gov (United States)

    Nonevicz, J. E.; Adamo, R. C.; Beers, B. L.; Delmer, T. N.

    1980-01-01

    The initial phase of a broader, more complete program for the characterization of electrical breakdowns on spacecraft insulating materials is described which consisted of the development of a discharge simulator and characterization facility and the performance of a limited number of discharge measurements to verify the operation of the laboratory setup and to provide preliminary discharge transient field data. A preliminary model of the electromagnetic characteristics of the discharge was developed. It is based upon the "blow off" current model of discharges, with the underlying assumption of a propagating discharge. The laboratory test facility and discharge characterization instrumentation are discussed and the general results of the "quick look" tests are described on quartz solar reflectors aluminized Kapton and silver coated Teflon are described.

  16. Feasibility of wear compensation in micro EDM milling based on discharge counting and discharge population characterization

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Hansen, Hans Nørgaard; Tristo, G.

    2011-01-01

    This paper investigates the applicability of real time wear compensation in micro EDM milling based on discharge counting and discharge population characterization. Experiments were performed involving discharge counting and tool electrode wear measurement in a wide range of process parameters...... settings involving different current pulse shapes. A strong correlation is found between average discharge energy of the populations and wear and material removal per discharge. A validation was carried out showing the feasibility of the proposed approach....

  17. Measurements of ion micro-beams in RPI-type discharges and fusion protons in PF-1000 experiments

    Science.gov (United States)

    Malinowska, A.; Malinowski, K.; Skladnik-Sadowska, E.; Sadowski, M. J.; Scholz, M.; Szydlowski, A.; Czaus, K.; Jaskola, M.; Korman, A.; Schmidt, H.

    2006-04-01

    The paper reports on experimental investigation of micro-beams of fast ions emitted from high-current pulse discharges within the RPI-IBIS (Rod Plasma Injector) device in Swierk and the PF-1000 (Plasma-Focus) facility in Warsaw. Time-integrated ion measurements were performed with pinhole cameras equipped with solid-state nuclear track detectors (SSNTDs). Before expositions the SSNTDs were calibrated by means of mono-energetic ion beams and/or Thomson-type parabolas recorded on the detector samples. The ion-pinhole cameras were placed at different angles to the symmetry axes of the investigated facilities. In order to record fast (>3 MeV) protons, which originated from D D nuclear fusion reactions in the PF-1000 facility, the SSNTDs were covered with appropriate Al filters. Time-integrated measurements of the fusion protons were performed for chosen series of PF discharges. The paper presents for the first time detailed maps of the fast proton fluxes, which makes it possible to draw conclusions regarding the spatial distribution of the fusion-proton sources.

  18. Microtearing modes in tokamak discharges

    Energy Technology Data Exchange (ETDEWEB)

    Rafiq, T.; Kritz, A. H. [Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Weiland, J. [Department of Applied Physics, Chalmers University, S41296 Gothenburg (Sweden); Luo, L. [IBM Research, Oak Ridge, Tennessee 37831 (United States); Pankin, A. Y. [Tech-X Corporation, Boulder, Colorado 80308 (United States)

    2016-06-15

    Microtearing modes (MTMs) have been identified as a source of significant electron thermal transport in tokamak discharges. In order to describe the evolution of these discharges, it is necessary to improve the prediction of electron thermal transport. This can be accomplished by utilizing a model for transport driven by MTMs in whole device predictive modeling codes. The objective of this paper is to develop the dispersion relation that governs the MTM driven transport. A unified fluid/kinetic approach is used in the development of a nonlinear dispersion relation for MTMs. The derivation includes the effects of electrostatic and magnetic fluctuations, arbitrary electron-ion collisionality, electron temperature and density gradients, magnetic curvature, and the effects associated with the parallel propagation vector. An iterative nonlinear approach is used to calculate the distribution function employed in obtaining the nonlinear parallel current and the nonlinear dispersion relation. The third order nonlinear effects in magnetic fluctuations are included, and the influence of third order effects on a multi-wave system is considered. An envelope equation for the nonlinear microtearing modes in the collision dominant limit is introduced in order to obtain the saturation level. In the limit that the mode amplitude does not vary along the field line, slab geometry, and strong collisionality, the fluid dispersion relation for nonlinear microtearing modes is found to agree with the kinetic dispersion relation.

  19. Silo Collapse under Granular Discharge

    Science.gov (United States)

    Gutiérrez, G.; Colonnello, C.; Boltenhagen, P.; Darias, J. R.; Peralta-Fabi, R.; Brau, F.; Clément, E.

    2015-01-01

    We investigate, at a laboratory scale, the collapse of cylindrical shells of radius R and thickness t induced by a granular discharge. We measure the critical filling height for which the structure fails upon discharge. We observe that the silos sustain filling heights significantly above an estimation obtained by coupling standard shell-buckling and granular stress distribution theories. Two effects contribute to stabilize the structure: (i) below the critical filling height, a dynamical stabilization due to granular wall friction prevents the localized shell-buckling modes to grow irreversibly; (ii) above the critical filling height, collapse occurs before the downward sliding motion of the whole granular column sets in, such that only a partial friction mobilization is at play. However, we notice also that the critical filling height is reduced as the grain size d increases. The importance of grain size contribution is controlled by the ratio d /√{R t }. We rationalize these antagonist effects with a novel fluid-structure theory both accounting for the actual status of granular friction at the wall and the inherent shell imperfections mediated by the grains. This theory yields new scaling predictions which are compared with the experimental results.

  20. Microtearing modes in tokamak discharges

    Science.gov (United States)

    Rafiq, T.; Weiland, J.; Kritz, A. H.; Luo, L.; Pankin, A. Y.

    2016-06-01

    Microtearing modes (MTMs) have been identified as a source of significant electron thermal transport in tokamak discharges. In order to describe the evolution of these discharges, it is necessary to improve the prediction of electron thermal transport. This can be accomplished by utilizing a model for transport driven by MTMs in whole device predictive modeling codes. The objective of this paper is to develop the dispersion relation that governs the MTM driven transport. A unified fluid/kinetic approach is used in the development of a nonlinear dispersion relation for MTMs. The derivation includes the effects of electrostatic and magnetic fluctuations, arbitrary electron-ion collisionality, electron temperature and density gradients, magnetic curvature, and the effects associated with the parallel propagation vector. An iterative nonlinear approach is used to calculate the distribution function employed in obtaining the nonlinear parallel current and the nonlinear dispersion relation. The third order nonlinear effects in magnetic fluctuations are included, and the influence of third order effects on a multi-wave system is considered. An envelope equation for the nonlinear microtearing modes in the collision dominant limit is introduced in order to obtain the saturation level. In the limit that the mode amplitude does not vary along the field line, slab geometry, and strong collisionality, the fluid dispersion relation for nonlinear microtearing modes is found to agree with the kinetic dispersion relation.

  1. Operational Characteristics of a High Voltage Dense Plasma Focus.

    Science.gov (United States)

    1985-11-01

    familia kinetic temperature is that of a molecular gas consisting of one particle species and complete space isotropy. Kinetic thermodynamic...Assuming sheath thickness of 1 cm, and area of 100 cm2 , the radiated power is Pb" erg/s. For 1 us rundown, the total radiated energy is Eb = 106

  2. Opening Switch Research on a Plasma Focus VI.

    Science.gov (United States)

    1988-02-26

    densi y ( -’cm-3 suggest that th. I asma is at max imu: compress ion. Xna xxmmn1m AVI JulmrW0 51 (a) PLASMA DENSITY (SCALE: 1.0=1.6- 1018CM-3 ) 1.0 .4 7...IEEE inter. Pulsed Power Conf., New Mexico , 350 (1983). 3. F. Venneri, and G. Gerdin, IEEE Int. Conf. on Plasma Sci., St. Louis, MO, 1984, Conf. Record

  3. Discharge processes of UV pre-ionized electric-discharge pulsed DF laser

    Science.gov (United States)

    Pan, Qikun; Xie, Jijiang; Shao, Chunlei; Wang, Chunrui; Shao, Mingzhen; Guo, Jin

    2016-03-01

    The discharge processes of ultraviolet (UV) pre-ionized electric-discharge pulsed DF laser operating with a SF6-D2 gas mixture are studied. A mathematical model based on continuity equation of electrons and Kirchhoff equations for discharge circuit is established to describe the discharge processes. Voltage and current waveforms of main discharge and voltage waveforms of pre-ionization are solved numerically utilizing the model. The calculations correctly display some physical processes, such as the delay time between pre-ionization and main discharge, breakdown of the main electrode and self-sustained volume discharge (SSVD). The results of theory are consistent with the experiments, which are performed in our non-chain pulsed DF laser. Then the delay inductance and peak capacitance are researched to analyze their influences on discharge processes, and the circuit parameters of DF laser are given which is useful to improve the discharge stability.

  4. Glow and pseudo-glow discharges in a surface discharge generator

    Institute of Scientific and Technical Information of China (English)

    Li Xue-Chen; Dong Li-Fang; Wang Long

    2005-01-01

    The glow discharge in flowing argon at one atmospheric pressure is realized in a surface discharge generator. The discharge current presents one peak per half-cycle of the applied voltage. The duration of the discharge pulse is more than 1μs when the frequency of the applied voltage is 60kHz. For the glow discharge in argon, the power consumption increases with the increase of voltage or the decrease of gas pressure.This relation is explained qualitatively based on the theory of the Townsend breakdown mechanism. In contrast, the discharge current in one atmospheric pressure air gives many spikes in each half-cycle, and correspondingly this kind of discharge is called pseudo-glow discharge. Every current spike oscillates with high-frequency damping. The pseudo-glow discharge in one atmospheric pressure air might result from the streamer breakdown mechanism.

  5. Stability of atmospheric pressure glow discharges

    Science.gov (United States)

    Chirokov, Alexandre V.

    There has been a considerable interest in non-thermal atmospheric pressure discharges over the past decade due to increased number of industrial applications. Although non-thermal atmospheric pressure discharges have been intensively studied for the past century the clear physical picture of these discharges is far from being complete. Spontaneous transition of non-thermal atmospheric pressure discharges to thermal discharge and discharge filamentation are among least understood plasma phenomena. The discharge stability and reliable control of plasma parameters are highly desirable for numerous applications. This study focuses on stability of atmospheric pressure glow discharges with respect to filamentation and arcing. Atmospheric pressure glow discharge (APG) is the newest and the most promising addition to the family of non-thermal atmospheric pressure discharges. However this discharge is very susceptible to thermal instability which causes arcing, loss of uniformity and significant damage to electrodes. Suppression of thermal instability and effective control of discharge parameters is critical for industrial applications. A model was developed to understand transition to arc in atmospheric pressure glow discharges. APG discharges that operate in pure helium and in helium with addition of oxygen and nitrogen were considered in these studies. Simulation results indicate that arcing is the result of sheath breakdown rather than thermal instability. It was shown that although sheath breakdown is always followed by overheating the transition to arc in atmospheric glow discharges is not a result of thermal instability. In second part of this research interaction between plasma filaments in dielectric barrier discharges has been studied. This interaction is responsible for the formation of microdischarge patterns reminiscent of two-dimensional crystals. Depending on the application, microdischarge patterns may have a significant influence on DBD performance

  6. Relativistic Electrons in Electric Discharges

    DEFF Research Database (Denmark)

    Cinar, Deniz

    discharges as the source. The “Atmosphere-Space Interactions Monitor” (ASIM) for the International Space Station in 2016, led by DTU Space, and the French microsatellite TARANIS, also with launch in 2016, will identify with certainty the source of TGFs. In preparation for the missions, the Ph.D. project has...... developed a Monte Carlo module of a simulation code to model the formation of avalanches of electrons accelerated to relativistic energies, and the generation of bremsstrahlung through interactions with the neutral atmosphere. The code will be used in the analysis of data from the two space missions. We...... scattering. However, we only explored the properties of the complete number of photons reaching space, not the distribution at speci_c locations as in the case of a satellite. With this reservation we conclude that it is not possible to deduce much information from a satellite measurement of the photons...

  7. Modelling Of Chlorine Inductive Discharges

    Science.gov (United States)

    Chabert P.; Despiau-Pujo, E.

    2010-07-01

    III-V compounds such as GaAs, InP or GaN-based materials are increasingly important for their use in optoelectronic applications, especially in the telecommunications and light detection industries. Photonic devices including lasers, photodetectors or LEDs, require reliable etching processes characterized by high etch rate, profile control and low damage. Although many problems remain to be understood, inductively coupled discharges seem to be promising to etch such materials, using Cl2/Ar, Cl2/N2 and Cl2/H2 gas chemistries. Inductively coupled plasma (ICP) sources meet most of the requirements for efficient plasma processing such as high etch rates, high ion densities and low controllable ion energies. However, the presence of a negative ion population in the plasma alters the positive ion flux, reduces the electron density, changes the electron temperature, modifies the spatial structure of the discharge and can cause unstable operation. Several experimental studies and numerical simulation results have been published on inductively coupled Cl2/Ar plasmas but relatively few systematic comparisons of model predictions and experimental data have been reported in given reactor geometries under a wide range of op- erating conditions. Validation of numerical predictions is essential for chemically complex plasma processing and there is a need to benchmark the models with as many measurements as possible. In this paper, comparisons of 2D fluid simulations with experimental measurements of Ar/Cl2 plasmas in a low pressure ICP reactor are reported (Corr et al. 2008). The electron density, negative ion fraction and Cl atom density are investigated for various conditions of Ar/Cl2 ratio, gas pressure and applied RF power in H mode. Simulations show that the wall recombination coefficient of Cl atom (?) is a key parameter of the model and that neutral densities are very sensitive to its variations. The best agreement between model and experiment is obtained for ? = 0

  8. Coordinated discharge of a collection of batteries

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, Shivakumar; Gimdogmus, Omer; Hartley, Tom T.; Veillette, Robert J. [Department of Electrical and Computer Engineering, The University of Akron, Akron, OH 44325-3904 (United States)

    2007-03-30

    Collections of batteries are used to supply energy to a variety of applications. By utilizing the energy in such a collection efficiently, we can improve the lifetime over which energy can be supplied to the application. We say that the discharge of a collection of batteries is coordinated when, at the end of discharge, the difference in the remaining capacity of individual batteries is small. This paper presents a decision-maker based on a goal-seeking formulation that coordinates the discharge of a collection of batteries. This formulation allows us to use a simple battery model and simple decision-making algorithms. We present results from MATLAB simulations that demonstrate the performance of the decision-maker when energy is drawn out of the collection in three different discharge scenarios. The new decision-maker consistently improves the discharge efficiency obtained using scheduling methods. Our results show that when the discharge is coordinated, the lifetime of the collection is extended. (author)

  9. Numerical modeling of partial discharges parameters

    Directory of Open Access Journals (Sweden)

    Kartalović Nenad M.

    2016-01-01

    Full Text Available In recent testing of the partial discharges or the use for the diagnosis of insulation condition of high voltage generators, transformers, cables and high voltage equipment develops rapidly. It is a result of the development of electronics, as well as, the development of knowledge about the processes of partial discharges. The aim of this paper is to contribute the better understanding of this phenomenon of partial discharges by consideration of the relevant physical processes in isolation materials and isolation systems. Prebreakdown considers specific processes, and development processes at the local level and their impact on specific isolation material. This approach to the phenomenon of partial discharges needed to allow better take into account relevant discharge parameters as well as better numerical model of partial discharges.

  10. Discharge estimation based on machine learning

    Institute of Scientific and Technical Information of China (English)

    Zhu JIANG; Hui-yan WANG; Wen-wu SONG

    2013-01-01

    To overcome the limitations of the traditional stage-discharge models in describing the dynamic characteristics of a river, a machine learning method of non-parametric regression, the locally weighted regression method was used to estimate discharge. With the purpose of improving the precision and efficiency of river discharge estimation, a novel machine learning method is proposed:the clustering-tree weighted regression method. First, the training instances are clustered. Second, the k-nearest neighbor method is used to cluster new stage samples into the best-fit cluster. Finally, the daily discharge is estimated. In the estimation process, the interference of irrelevant information can be avoided, so that the precision and efficiency of daily discharge estimation are improved. Observed data from the Luding Hydrological Station were used for testing. The simulation results demonstrate that the precision of this method is high. This provides a new effective method for discharge estimation.

  11. Heating dominated inception of pulsed discharges

    Science.gov (United States)

    Agnihotri, Ashutosh; Hundsdorfer, Willem; Ebert, Ute

    2016-09-01

    We simulate the inception of pulsed discharges with heating as the driving agent that leads to spark formation. To understand the phenomenon, we developed a 2D-cylindrically symmetric model that couples the electric discharge dynamics with the background gas dynamics. To capture the ion dynamics well, we reduced the classical drift-diffusion-reaction model of electric discharges to the timescale of ion motion. Additionally, we include secondary emission of electrons from the cathode. We employed the model to study electrical breakdown in air at STP conditions between planar electrodes under the application of pulsed voltages. Our model captures space-charge effects, thermal shocks and induced pressure waves. We observe a cycle of discharge pulses heating the gas and the thermal expansion helping the discharge. This cycle might either lead to spark formation or to discharge decay.

  12. Role of secondary emission on discharge dynamics in an atmospheric pressure dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Tay, W. H.; Kausik, S. S.; Yap, S. L.; Wong, C. S., E-mail: cswong@um.edu.my [Plasma Technology Research Centre, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-04-15

    The discharge dynamics in an atmospheric pressure dielectric barrier discharge (DBD) is studied in a DBD reactor consisting of a pair of stainless steel parallel plate electrodes. The DBD discharge has been generated by a 50 Hz ac high voltage power source. The high-speed intensified charge coupled device camera is used to capture the images of filaments occurring in the discharge gap. It is observed that frequent synchronous breakdown of micro discharges occurs across the discharge gap in the case of negative current pulse. The experimental results reveal that secondary emissions from the dielectric surface play a key role in the synchronous breakdown of plasma filaments.

  13. Plasma spark discharge reactor and durable electrode

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young I.; Cho, Daniel J.; Fridman, Alexander; Kim, Hyoungsup

    2017-01-10

    A plasma spark discharge reactor for treating water. The plasma spark discharge reactor comprises a HV electrode with a head and ground electrode that surrounds at least a portion of the HV electrode. A passage for gas may pass through the reactor to a location proximate to the head to provide controlled formation of gas bubbles in order to facilitate the plasma spark discharge in a liquid environment.

  14. Investigations into electrical discharges in gases

    CERN Document Server

    Klyarfel'D, B N

    2013-01-01

    Investigations into Electrical Discharges in Gases is a compilation of scientific articles that covers the advances in the investigation of the fundamental processes occurring in electrical discharges in gases and vapors. The book details the different aspects of the whole life cycle of an arc, which include the initiation of a discharge, its transition into an arc, the lateral spread of the arc column, and the recovery of electric strength after extinction of an arc. The text also discusses the methods for the dynamic measurement of vapor density in the vicinity of electrical discharges, alon

  15. Parallel Operation of Microhollow Cathode Discharges

    Science.gov (United States)

    Stark, Robert H.; Shi, Wenhui; Schoenbach, Karl H.

    1998-10-01

    The dc current-voltage characteristics of microhollow cathode discharges has, in certain ranges of the discharge current, a positive slope [1]. In these current ranges it should be possible to operate multiple discharges in parallel without individual ballast, and be used as flat panel excimer lamps [2] or large area plasma cathodes. In order to verify this hypothesis we have studied the parallel operation of two microhollow cathode discharges of 100 micrometer hole diameter in argon at pressures from 100 Torr to 800 Torr. Stable dc operation of the two discharges, without individual ballast, was obtained if the voltage-current characteristics of the individual discharges had a positive slope greater than 10 V/mA over a voltage range of more than 5 to obtain parallel operation over the entire current range of the microhollow cathode discharges, which includes regions of negative differential conductivity, we have replaced the metal anode by a semi-insulating semiconductor, which serves as distributed resistive ballast. With this method, we were able to ignite and sustain an array of dc microhollow cathode discharges over a wide range of pressure and discharge current. [1] K.H.Schoenbach et al. Appl. Phys. Lett. 68, 13 (1996). [2] A.El-Habachi and K.H.Schoenbach, APL. 72, 1 (1998). This work was funded by the Department of Energy, Advanced Energy Division, and by the Air Force Office of Scientific Research (AFOSR) in cooperation with the DDR&E Air Plasma Ramparts MURI Program.

  16. Surface water discharges from onshore stripper wells.

    Energy Technology Data Exchange (ETDEWEB)

    Veil, J. A.

    1998-01-16

    Under current US Environmental Protection Agency (EPA) rules, small onshore oil producers are allowed to discharge produced water to surface waters with approval from state agencies; but small onshore gas producers, however, are prohibited from discharging produced water to surface waters. The purpose of this report is to identify those states that allow surface water discharges from small onshore oil operations and to summarize the types of permitting controls they use. It is intended that the findings of this report will serve as a rationale to encourage the EPA to revise its rules and to remove the prohibition on surface water discharges from small gas operations.

  17. Device for generation of pulsed corona discharge

    Science.gov (United States)

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

    2012-05-08

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

  18. Discharge Characteristics in Atmospheric Pressure Glow Surface Discharge in Helium Gas

    Institute of Scientific and Technical Information of China (English)

    LI Xue-Chen; WANG Long

    2005-01-01

    @@ Atmospheric pressure glow discharge is observed for the first time in a surface discharge generator in flowing helium. Electrical and optical methods are used to measure the characteristics of atmospheric pressure glow discharge for different voltages. The results show that discharge current waveforms are asymmetric for the different polarities of the applied voltage. A continuous discharge profile with a width of several microseconds appears for per half cycle of the applied voltage when the voltage is increased to a certain value. The short-pulsed discharge and the continuous current would result from the Townsend breakdown and glow discharge mechanisms respectively. The properties of surface discharge in stagnant helium are completely different from that in flowing helium.

  19. Discharge lamp with reflective jacket

    Science.gov (United States)

    MacLennan, Donald A.; Turner, Brian P.; Kipling, Kent

    2001-01-01

    A discharge lamp includes an envelope, a fill which emits light when excited disposed in the envelope, a source of excitation power coupled to the fill to excite the fill and cause the fill to emit light, and a reflector disposed around the envelope and defining an opening, the reflector being configured to reflect some of the light emitted by the fill back into the fill while allowing some light to exit through the opening. The reflector may be made from a material having a similar thermal index of expansion as compared to the envelope and which is closely spaced to the envelope. The envelope material may be quartz and the reflector material may be either silica or alumina. The reflector may be formed as a jacket having a rigid structure which does not adhere to the envelope. The lamp may further include an optical clement spaced from the envelope and configured to reflect an unwanted component of light which exited the envelope back into the envelope through the opening in the reflector. Light which can be beneficially recaptured includes selected wavelength regions, a selected polarization, and selected angular components.

  20. The radiofrequency magnetic dipole discharge

    Science.gov (United States)

    Martines, E.; Zuin, M.; Marcante, M.; Cavazzana, R.; Fassina, A.; Spolaore, M.

    2016-05-01

    This paper describes a novel and simple concept of plasma source, which is able to produce a radiofrequency magnetized discharge with minimal power requirements. The source is based on the magnetron concept and uses a permanent magnet as an active electrode. The dipolar field produced by the magnet confines the electrons, which cause further ionization, thus producing a toroidally shaped plasma in the equatorial region around the electrode. A plasma can be ignited with such scheme with power levels as low as 5 W. Paschen curves have been built for four different working gases, showing that in Helium or Neon, plasma breakdown is easily obtained also at atmospheric pressure. The plasma properties have been measured using a balanced Langmuir probe, showing that the electron temperature is around 3-4 eV and higher in the cathode proximity. Plasma densities of the order of 1016 m-3 have been obtained, with a good positive scaling with applied power. Overall, the electron pressure appears to be strongly correlated with the magnetic field magnitude in the measurement point.

  1. KSC Electrostatic Discharge (ESD) Issues

    Science.gov (United States)

    Buhler, Charles

    2008-01-01

    Discussion of key electrostatic issues that have arisen during the past few years at KSC that the Electrostatics Laboratory has studied. The lab has studied in depth the Space Shuttle's Thermal Control System Blankets, the International Space Station Thermal Blanket, the Pan/Tilt Camera Blankets, the Kapton Purge Barrier Curtain, the Aclar Purge Barrier Curtain, the Thrust Vector Controller Blankets, the Tyvek Reaction Control System covers, the AID-PAK and FLU-9 pyro inflatable devices, the Velostat Solid Rocket Booster mats, and the SCAPE suits. In many cases these materials are insulating meaning that they might be a source of unsafe levels of electrostatic discharge (ESD). For each, the lab provided in-depth testing of each material within its current configuration to ensure that it does not cause an ESD concern that may violate the safety of the astronauts, the workers and equipment for NASA. For example the lab provides unique solutions and testing such as Spark Incendivity Testing that checks whether a material is capable of generating a spark strong enough to ignite a flammable gas. The lab makes recommendations to changes in specifications, procedures, and material if necessary. The lab also consults with a variety of non-safety related ESD issues for the agency.

  2. Arc discharge sliding over a conducting surface

    NARCIS (Netherlands)

    Goor, van F.A.; Mitko, S.V.; Ochkin, V.N.; Paramonov, A.P.; Witteman, W.J.

    1997-01-01

    Results of experimental and theoretical studies of the arc discharge which slides over the surface of a conductor are reported. Experiments were performed in air and argon ambients at various pressures. It is found that the velocity of the discharge plasma front depends linearly on the strength of t

  3. Pulse volume discharges in high pressure gases

    Science.gov (United States)

    Yamshchikov, V. A.

    2015-11-01

    New approach for suppression of plasma inhomogeneities and instabilities in the volume self-sustained discharge is offered. The physical model is offered and conditions of obtaining extremely homogeneous self-sustained discharge are defined (with full suppression of plasma inhomogeneity and instability). Results of calculations agree with experiments.

  4. Plasma discharge self-cleaning filtration system

    Science.gov (United States)

    Cho, Young I.; Fridman, Alexander; Gutsol, Alexander F.; Yang, Yong

    2014-07-22

    The present invention is directed to a novel method for cleaning a filter surface using a plasma discharge self-cleaning filtration system. The method involves utilizing plasma discharges to induce short electric pulses of nanoseconds duration at high voltages. These electrical pulses generate strong Shockwaves that disintegrate and dislodge particulate matter located on the surface of the filter.

  5. Generation of nanoparticles by spark discharge

    NARCIS (Netherlands)

    Tabrizi, N.S.; Ullmann, M.; Vons, V.A.; Lafont, U.; Schmidt-Ott, A.

    2008-01-01

    The production of nanoparticles by microsecond spark discharge evaporation in inert gas is studied systematically applying transmission electron microscopy, mobility analysis and BET surface area measurement. The method of spark discharge is of special interest, because it is continuous, clean, extr

  6. Aerated bunker discharge of fine dilating powders

    NARCIS (Netherlands)

    Ouwerkerk, C.E.D.; Molenaar, H.J.; Frank, M.J.W.

    1992-01-01

    The discharge rate of coarse powders (mean particle size 500 ¿m) from bunkers without aeration can be described by both empirical relations and theoretical models. In the case of small particles the discharge rate is largely overestimated. As the powder dilates during flow a negative pressure gradie

  7. Eddy correlation measurements of submarine groundwater discharge

    Science.gov (United States)

    Crusius, J.; Berg, P.; Koopmans, D.J.; Erban, L.

    2008-01-01

    This paper presents a new, non-invasive means of quantifying groundwater discharge into marine waters using an eddy correlation approach. The method takes advantage of the fact that, in virtually all aquatic environments, the dominant mode of vertical transport near the sediment-water interface is turbulent mixing. The technique thus relies on measuring simultaneously the fluctuating vertical velocity using an acoustic Doppler velocimeter and the fluctuating salinity and/or temperature using rapid-response conductivity and/or temperature sensors. The measurements are typically done at a height of 5-15??cm above the sediment surface, at a frequency of 16 to 64??Hz, and for a period of 15 to 60??min. If the groundwater salinity and/or temperature differ from that of the water column, the groundwater specific discharge (cm d- 1) can be quantified from either a heat or salt balance. Groundwater discharge was estimated with this new approach in Salt Pond, a small estuary on Cape Cod (MA, USA). Estimates agreed well with previous estimates of discharge measured using seepage meters and 222Rn as a tracer. The eddy correlation technique has several desirable characteristics: 1) discharge is quantified under in-situ hydrodynamic conditions; 2) salinity and temperature can serve as two semi-independent tracers of discharge; 3) discharge can be quantified at high temporal resolution, and 4) long-term records of discharge may be possible, due to the low power requirements of the instrumentation. ?? 2007 Elsevier B.V. All rights reserved.

  8. Computing discharge using the index velocity method

    Science.gov (United States)

    Levesque, Victor A.; Oberg, Kevin A.

    2012-01-01

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

  9. Estimation of combined sewer overflow discharge

    DEFF Research Database (Denmark)

    Ahm, Malte; Thorndahl, Søren Liedtke; Nielsen, Jesper Ellerbæk;

    2016-01-01

    Combined sewer overflow (CSO) structures are constructed to effectively discharge excess water during heavy rainfall, to protect the urban drainage system from hydraulic overload. Consequently, most CSO structures are not constructed according to basic hydraulic principles for ideal measurement...... weirs. It can, therefore, be a challenge to quantify the discharges from CSOs. Quantification of CSO discharges are important in relation to the increased environmental awareness of the receiving water bodies. Furthermore, CSO discharge quantification is essential for closing the rainfall-runoff mass......-balance in combined sewer catchments. A closed mass-balance is an advantage for calibration of all urban drainage models based on mass-balance principles. This study presents three different software sensor concepts based on local water level sensors, which can be used to estimate CSO discharge volumes from hydraulic...

  10. Characterisation of pulsed discharge in water

    Science.gov (United States)

    Kocik, Marek; Dors, Miroslaw; Podlinski, Janusz; Mizeraczyk, Jerzy; Kanazawa, Seiji; Ichiki, Ryuta; Sato, Takehiko

    2013-10-01

    In this paper, Schlieren photography technique has been applied for the visualization of the pressure field of a single-shot underwater pulsed discharge. A needle-to-plane electrode configuration submerged in distilled water was used. The detailed time- and space-resolved images of both streamers and pressure waves were captured. As a result, several phenomena, such as the phase change prior to the initiation of the discharge, primary and secondary streamers propagation, shock wave generation, and the bubble formation, were observed. From these observations, a scenario of multiple events from prebreakdown to post-discharge was proposed. The gas bubbles generated in discharge were used to visualize the electrohydrodynamic flow induced by the discharge. This work was presented on the occasion of the 13th International Symposium on High Pressure Low Temperature Plasma Chemistry (Hakone XIII).

  11. Influence on discharge uniformity of electrodes configuration

    CERN Document Server

    Zheng Jian; Sui Zhan; Lu Jing Ping; Zheng Kui Xing; Zhang Xiong Jun; Dong Yun; Feng Bin

    2002-01-01

    Large area glow discharge plasma that is transparent and highly conductive can be used as electrodes in Pockels cell to extend the switch aperture. To investigate this technology, a glow discharging chamber with a clear aperture of 5 cm x 5 cm was constructed, and hollow cathode, button cathode, pin cathode, bar cathode and bar anode were designed and produced. Using CCD imaging system, the discharging uniformity of different cathodes was tested with bar anode and under the different pressure pre-ionization voltage and main discharging voltage. A uniform plasma can be obtained with a hollow cathode when the pre-ionization voltage is about 700 V, the pressure is about 30 Pa, and the main discharging voltage is about 4 kV, which can be used for the plasma electrode of Pockels cell

  12. Discharge coefficient of small sonic nozzles

    Directory of Open Access Journals (Sweden)

    Yin Zhao-Qin

    2014-01-01

    Full Text Available The purpose of this investigation is to understand flow characteristics in mini/micro sonic nozzles, in order to precisely measure and control miniscule flowrates. Experimental and numerical simulation methods have been used to study critical flow Venturi nozzles. The results show that the nozzle’s size and shape influence gas flow characteristics which leading the boundary layer thickness to change, and then impact on the discharge coefficient. With the diameter of sonic nozzle throat decreasing, the discharge coefficient reduces. The maximum discharge coefficient exits in the condition of the inlet surface radius being double the throat diameter. The longer the diffuser section, the smaller the discharge coefficient becomes. Diffuser angle affects the discharge coefficient slightly.

  13. Impact of Pharmacist Facilitated Discharge Medication Reconciliation

    Directory of Open Access Journals (Sweden)

    Todd M. Super

    2014-07-01

    Full Text Available Preventable adverse drug events occur frequently at transitions in care and are a problem for many patients following hospital discharge. Many of these problems can be attributed to poor medication reconciliation. The purpose of this study was to assess the impact that direct pharmacist involvement in the discharge medication reconciliation process had on medication discrepancies, patient outcomes, and satisfaction. A cohort study of 70 patients was designed to assess the impact of pharmacist facilitated discharge medication reconciliation at a 204-bed community hospital in Battle Creek, Michigan, USA. Discharge summaries were analyzed to compare patients who received standard discharge without pharmacist involvement to those having pharmacist involvement. The total number of discrepancies in the group without pharmacist involvement was significantly higher than that of the pharmacist facilitated group.

  14. Helium corona-assisted air discharge

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Nan; Gao Lei; Ji Ailing; Cao Zexian [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2011-10-15

    Operation of atmospheric discharge of electronegative gases including air at low voltages yet without consuming any inert gas will enormously promote the application of non-thermal plasmas. By taking advantage of the low onset voltage for helium corona, air discharge was successfully launched at much reduced voltages with a needle-plate system partly contained in a helium-filled glass bulb--for a needle-plate distance of 12 mm, 1.0 kV suffices. Ultraviolet emission from helium corona facilitates the discharging of air, and the discharge current manifests distinct features such as relatively broad Trichel pulses in both half periods. This design allows safe and economic implementation of atmospheric discharge of electronegative gases, which will find a broad palette of applications in surface modification, plasma medicine and gas treatment, etc.

  15. The making of local hospital discharge arrangements

    DEFF Research Database (Denmark)

    Burau, Viola; Bro, Flemming

    2015-01-01

    Background Timely discharge is a key component of contemporary hospital governance and raises questions about how to move to more explicit discharge arrangements. Although associated organisational changes closely intersect with professional interests, there are relatively few studies...... and involvement in the process of organisational change: whereas in the ‘add on’ model the professional groups remain at a distance, in the ‘embedded model’ they are closely engaged. Conclusions In terms of understanding the making of hospital discharge arrangements, the study contributes two sets of insights...... in the literature on hospital discharge that explicitly examine the role of professional groups. Recent contributions to the literature on organisational studies of the professions help to specify how professional groups in hospitals contribute to the introduction and routinisation of discharge arrangements...

  16. Numerical investigation of dielectric barrier discharges

    Science.gov (United States)

    Li, Jing

    1997-12-01

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

  17. Discharge analysis and electrical modeling for the development of efficient dielectric barrier discharge

    Science.gov (United States)

    Pal, U. N.; Kumar, M.; Tyagi, M. S.; Meena, B. L.; Khatun, H.; Sharma, A. K.

    2010-02-01

    Dielectric-barrier discharges (DBDs) are characterized by the presence of at least one insulating layer in contact with the discharge between two planar or cylindrical electrodes connected to an AC/pulse power supply. The dielectric layers covering the electrodes act as current limiters and prevent the transition to an arc discharge. DBDs exist usually in filamentary mode, based on the streamer nature of the discharges. The main advantage of this type of electrical discharges is that nonequilibrium and non-thermal plasma conditions can be established at atmospheric pressure. VUV/UV sources based on DBDs are considered as promising alternatives of conventional mercury-based discharge plasmas, producing highly efficient VUV/UV radiation. The experiments have been performed using two coaxial quartz double barrier DBD tubes, which are filled with Xe/Ar at different pressures. A sinusoidal voltage up to 2.4 kV peak with frequencies from 20 to 100 kHz has been applied to the discharge electrodes for the generation of microdischarges. A stable and uniform discharge is produced in the gas gap between the dielectric barrier electrodes. By comparisons of visual images and electrical waveforms, the filamentary discharges for Ar tube while homogeneous discharge for Xe tube at the same conditions have been confirmed. The electrical modeling has been carried out to understand DBD phenomenon in variation of applied voltage waveforms. The simulated discharge characteristics have been validated by the experimental results.

  18. Influence of Four Factors on Discharge Capacity and Self-Discharge Rate of Iron Electrode

    Institute of Scientific and Technical Information of China (English)

    Dongfeng LIN; Shihai YE; Rong CAI; Deying SONG; Panwen SHEN

    2003-01-01

    Ni-Fe rechargeable batteries possess the advantages of long cycle life, high theoretical specific energy, abundant raw material,Iow price and environmental friendship. It has a wide applied perspective. The advantages, disadvantages and preparation methods of iron electrodes were summarized. The influence of four factors on discharge capacity and self-discharge rate of iron electrode were discussed by means of orthogonal experiments, galvanostatic charges and discharges. The influences of graphite on the discharge capacity and self-discharge rate of iron electrode were the most remarkable, the most unapparent influences on the discharge capacity and self-discharge rate were HPMC (hydroxy propoxy methoxy cellulose) and sodium sulphide, respectively. The aim of the present research was to study the effects of graphite, HPMC and iron powder added in the electrodes, sodium sulphide added in the electrolytes on the discharge capacity and self-discharge rate of iron electrodes.The largest discharge capacity of the iron electrodes was 488.5 mAh/g-Fe at 66.4 mA/g-Fe in the first ten cycles, and the average self-discharge rate was 0.367% per hour.

  19. High-pressure hollow cathode discharges

    Science.gov (United States)

    Schoenbach, Karl H.; El-Habachi, Ahmed; Shi, Wenhui; Ciocca, Marco

    1997-11-01

    Reducing the diameter of the cathode hole in a plane anode - hollow cathode geometry to 0963-0252/6/4/003/img1m has allowed us to generate direct current discharges in argon at atmospheric pressure. Up to pressure times cathode hole diameter (pD) values of approximately 5 Torr cm, and at sub-mA currents, glow discharges (predischarges) are observed with a shape which is determined by the vacuum electric field. In the same pD range, but at higher currents of up to approximately 4 mA, the discharges are of the hollow cathode discharge type. At pD values exceeding 5 Torr cm the predischarges turn into surface discharges along the mica spacer between the electrodes. At currents > 4 mA filamentary, pulsed discharges are observed. Qualitative information on the electron energy distribution in the microdischarges has been obtained by studying the VUV emission from ionized argon atoms and the argon excimer radiation at 130 nm. The results of the spectral measurements indicate the presence of a relatively large concentration of electrons with energies > 15 eV over the entire pressure range. The fact that the current - voltage characteristic of the microdischarges has a positive slope over much of the current range where excimer radiation is emitted indicates the possibility of forming arrays of these discharges and using them in flat panel excimer lamps.

  20. Whiteboards and discharge traffic lights: visual management in acute care.

    Science.gov (United States)

    O'Brien, Lauri; Bassham, Jane; Lewis, Melissa

    2015-04-01

    Flinders Medical Centre was experiencing issues with timely discharge and knowing the potential discharges and in-patient bed capacity for the next day. This case study describes the application of 'visual management' theory to discharge processes. The solutions developed were 'patient journey boards' and 'discharge traffic lights'. The implementation of these visual management systems has enabled the hospital to improve its discharge processes.

  1. Modes of Homogeneous Barrier Discharge at Atmospheric Pressure in Helium

    Institute of Scientific and Technical Information of China (English)

    WANG Yan-Hui; WANG De-Zhen

    2004-01-01

    @@ The discharge modes of a homogeneous barrier discharge at atmospheric pressure in helium are investigated with a one-dimensional fluid model It is found that, either in single peak discharge or in multipeak discharge, there are two discharge modes: glow and Townsend modes. The structure and features of the two modes are compared.The conditions forming the two modes are discussed.

  2. Mechanism of Striation in Dielectric Barrier Discharge

    Institute of Scientific and Technical Information of China (English)

    FENG Shuo; HE Feng; OUYANG Ji-Ting

    2007-01-01

    @@ The mechanism of striations in dielectric barrier discharge in pure neon is studied by a two-dimensional particlein-cell/Monte Carlo collision (PIC-MCC) model. It is shown that the striations appear in the plasma background,and non-uniform electrical field resulting from ionization and the negative wall charge appear on the dielectric layer above the anode. The sustainment of striations is a non-local kinetic effect of electrons in a stratified field controlled by non-elastic impact with neutral gases. The striations in the transient dielectric barrier discharge are similar to those in dc positive column discharge.

  3. Biological and Agricultural Studies on Application of Discharge Plasma and Electromagnetic Fields 2.Sterilization by Electrical Discharges and Plasmas

    Science.gov (United States)

    Watanabe, Takayuki

    The use of electrical discharges and plasmas for sterilization is reviewed. Plasmas generated by a silent discharge, a pulse discharge, and a radio frequency discharge under atmospheric pressure have been used for sterilization. Furthermore, a microwave plasma, a radio frequency plasma, and a low temperature plasma with hydrogen peroxide under low pressure conditions have been also used for sterilization. Sterilization results from injury caused by the discharge current, and from the reaction of species affected by the discharge. A silent discharge with air or oxygen is most effective for the sterilization. Nitrogen discharge also has a significant effect, however, argon discharge does not have a significant effect.

  4. Hospital discharge of respiratory-technology-dependent children: role of a dedicated respiratory care discharge coordinator.

    Science.gov (United States)

    Tearl, Donna K; Cox, Timothy J; Hertzog, James H

    2006-07-01

    Preparation of respiratory-technology-dependent children for hospital discharge presents many challenges. Adequate training and education of parental caregivers, discharge planning, and coordination with the durable-medical-equipment and home-nursing companies must be completed. A process using multiple respiratory therapists (RTs) to achieve this may not be efficient. We evaluated our model, in which a dedicated RT discharge coordinator provides education and coordinates discharge planning of respiratory-technology-dependent pediatric patients. This system provides a single contact for caregivers and outside agencies, a single respiratory-care educator for the caregivers, and a clinical pathway that involves the entire multidisciplinary team. Patient length of stay and customer satisfaction were evaluated before and after implementation of the discharge-coordinator program. Our dedicated-RT-discharge-coordinator model was associated with rapid initiation of frequent family-training sessions. Durable-medical-equipment-company personnel reported that they had increased satisfaction with the quality of training of the family caregivers. The members of the hospital multidisciplinary team had increased satisfaction with the discharge process. Patient length of stay nonsignificantly decreased after the implementation of the discharge-coordinator program. There are several advantages to using a dedicated RT-discharge-coordinator system for home-discharge preparation of respiratory-technology-dependent children.

  5. Fractal characterization of surface electrical discharges

    Energy Technology Data Exchange (ETDEWEB)

    Egiziano, L.; Femia, N.; Lupo' , G.; Tucci, V. (Salerno Univ. (Italy). Ist. di Ingegneria Elettronica Naples Univ. (Italy). Dip. di Ingegneria Elettrica)

    1991-01-01

    The concepts of fractal geometry have been usefully applied to describe several physical processes whose growth mechanisms are characterized by complex topological structures. The fractal characterization of electrical discharges taking place at the air/solid dielectric interface is considered in this paper. A numerical procedure allowing the reproduction the typical discharge patterns, known as Lichtenberg figures, is presented: the growth process of the discharge is simulated by solving iteratively the Laplace equation with moving boundary conditions and by considering two power probability laws whose exponents determine the ramification level of the structure. The discharge patterns are then considered as fractal sets and their characteristic parameters are determined. The dependence of the typical structures on the two exponents of the probability laws are also discussed.

  6. Pulsed electrical discharge in conductive solution

    Science.gov (United States)

    Panov, V. A.; Vasilyak, L. M.; Vetchinin, S. P.; Pecherkin, V. Ya; Son, E. E.

    2016-09-01

    Electrical discharge in a conductive solution of isopropyl alcohol in tap water (330 μ S cm-1) has been studied experimentally applying high voltage millisecond pulses (rise time  ˜0.4 μ \\text{s} , amplitude up to 15 kV, positive polarity) to a pin anode electrode. Dynamic current-voltage characteristics synchronized with high-speed images of the discharge were studied. The discharge was found to develop from high electric field region in the anode vicinity where initial conductive current with density  ˜100 A cm-2 results in fast heating and massive nucleation of vapor bubbles. Discharges in nucleated bubbles then produce a highly conductive plasma region and facilitate overheating instability development with subsequent formation of a thermally ionized plasma channel. The measured plasma channel propagation speed was 3-15 m s-1. A proposed thermal model of plasma channel development explains the low observed plasma channel propagation speed.

  7. Sawdust discharge rate from aerated hoppers

    Institute of Scientific and Technical Information of China (English)

    Pan Chen; Zhulin Yuan; Chien-Song Chyang; Fu-Xiong Zhuan

    2011-01-01

    This paper presents a numerical and experimental study of the discharge rate of sawdust from an aerated hopper as an important parameter in many industrial processes involving the handling of other granular materials. Numerical experiments are conducted by means of an Eulerian-Eulerian approach coupled with the kinetic theory of granular flow (KTGF). Emphasis is given to the effects of particle size, hopper outlet width, hopper half angle, aeration height and air flow rate. The results show that the discharge rate is significantly affected by hopper outlet width, particle size and air flow rate, but is not sensitive to the hopper half angle and aeration height: increasing hopper outlet width or air flow rate increases discharge rate, while increasing particle size decreases discharge rate. Close agreement between numerical predictions and experimental results is obtained.

  8. Leaving the hospital - your discharge plan

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000867.htm Leaving the hospital - your discharge plan To use the sharing features ... please enable JavaScript. After an illness, leaving the hospital is your next step toward recovery. Depending on ...

  9. On current termination in rotamak discharges

    Energy Technology Data Exchange (ETDEWEB)

    Donaldson, N.; Euripides, P.; Jones, I.R.; Xu, S. [Flinders Univ. of South Australia, Bedford Park, SA (Australia). School of Physical Sciences

    1995-03-01

    A new series of rotamak experiments conducted in a 50 litre spherical pyrex discharge vessel is described. An analysis of the results, together with that of previous results from a smaller, 10 litre vessel, provides an explanation for the current termination phenomenon which is such a noteworthy and characteristic feature of all rotamak discharges studied to date. It is shown that the amplitude of the applied rotating magnetic field, B{sub {omega}}, has to be greater than a certain critical value, B{sub {omega}}{sup crit}, for the rotamak discharge to be maintained. Provided B{sub {omega}} {>=} B{sub {omega}}{sup crit}, the properties of the discharge are then determined by the behaviour of the circuit used to couple the RF generators to the plasma load. The conditions necessary for the production of a compact toroidal magnetic configuration are presented. (author).

  10. Parental experiences of early postnatal discharge

    DEFF Research Database (Denmark)

    Nilsson, Ingrid; Danbjørg, Dorthe B.; Aagaard, Hanne

    2015-01-01

    and taking responsibility; A time of insecurity; Being together as a family; and Striving to be confident. The mothers׳ and fathers׳ experiences of responsibility, security and confidence in their parental role, were positively influenced by having the opportunity to be together as a family, receiving...... postnatal care that included both parents, having influence on time of discharge, and getting individualised and available support focused on developing and recognising their own experiences of taking care of the baby. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: the new parents׳ experiences of early...... discharge and becoming a parent were closely related. Feeling secure and confident in the parental role was positively or negatively influenced by the organisation of early discharge. This underscores the importance of the way health professionals support new mothers and fathers at early postnatal discharge....

  11. Electroformed Electrodes for Electrical-Discharge Machining

    Science.gov (United States)

    Werner, A.; Cassidenti, M.

    1984-01-01

    Copper electrodes replace graphite electrodes in many instances of electrical-discharge machining (EDM) of complex shapes. Copper electrodes wear longer and cause less contamination of EDM dielectric fluid than do graphite electrodes.

  12. Contamination-Free Electrical-Discharge Machining

    Science.gov (United States)

    Schmidt, Mark G.

    1987-01-01

    Contamination of parts by electrical-discharge machining (EDM) almost completely eliminated by reversing flow of coolant. Flow reversed from usual direction so coolant carries contaminants out through passage in electrode. Coolant for reverse flow is pressurized dichlorodifluoromethane vapor.

  13. Electrical-Discharge Machining Of Perpendicular Passages

    Science.gov (United States)

    Malinzak, R. Michael; Booth, Gary N.

    1996-01-01

    Perpendicular telescoping electrode used to perform electrical-discharge machining (EDM) of internal passage through previously inaccessible depth of metal workpiece. More specifically, used to make internal passage perpendicular to passage entering from outer surface.

  14. Setup Aid for Electrical-Discharge Machining

    Science.gov (United States)

    Lines, G.; Duca, J.

    1985-01-01

    Interlock assures that workpiece is correctly assembled in machining fixture. A Plunger in a Hollow Shaft actuates a switch, allowing a power supply to produce current for electrical-discharge machining. Plunger operates only when necessary parts are position.

  15. Mobile electric vehicles online charging and discharging

    CERN Document Server

    Wang, Miao; Shen, Xuemin (Sherman)

    2016-01-01

    This book examines recent research on designing online charging and discharging strategies for mobile electric vehicles (EVs) in smart grid. First, the architecture and applications are provided. Then, the authors review the existing works on charging and discharging strategy design for EVs. Critical challenges and research problems are identified. Promising solutions are proposed to accommodate the issues of high EV mobility, vehicle range anxiety, and power systems overload. The authors investigate innovating charging and discharging potentials for mobile EVS based on real-time information collections (via VANETS and/or cellular networks) and offer the power system adjustable load management methods.  Several innovative charging/discharging strategy designs to address the challenging issues in smart grid, i.e., overload avoidance and range anxiety for individual EVs, are presented. This book presents an alternative and promising way to release the pressure of the power grid caused by peak-time EV charging ...

  16. Research on Nanosecond Pulse Corona Discharge Attenuation

    Institute of Scientific and Technical Information of China (English)

    HE Zheng-hao; XU Huai-li; BAI Jing; YU Fu-sheng; HU Feng; LI Jin

    2007-01-01

    A line-to-plate reactor was set-up in the experimental study on the application of nanosecond pulsed corona discharge plasma technology in environmental pollution control.Investigation on the attenuation and distortion of the amplitude of the pulse wave front and the discharge image as well as the waveform along the corona wire was conducted.The results show that the wave front decreases sharply during the corona discharge along the corona wire.The higher the amplitude of the applied pulse is,the more the amplitude of the wave front decreased.The wave attenuation responds in a lower corona discharge inversely.To get a higher efficiency of the line-to-plate reactor a sharp attenuation of the corona has to be considered in practical design.

  17. Cleft lip and palate repair - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000004.htm Cleft lip and palate repair - discharge To use the sharing ... Elsevier Saunders; 2015:chap 8. Read More Cleft lip and palate Cleft lip and palate repair Review Date 5/9/ ...

  18. Abdominal aortic aneurysm repair - open - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000240.htm Abdominal aortic aneurysm repair - open - discharge To use the sharing features ... References Orandi BJ, Black JH. Open repair of abdominal aortic aneurysms. In: Cameron JL, Cameron AM, eds. Current Surgical ...

  19. Pulsed discharge plasmas in supercritical carbon dioxide

    OpenAIRE

    Kiyan, Tsuyoshi; Uemura, A.; Tanaka, K.; Zhang, C. H.; Namihira, Takao; Sakugawa, Takashi; Katsuki, Sunao; Akiyama, Hidenori; Roy, B.C.; Sasaki, M.; Goto, M.; キヤン, ツヨシ; ナミヒラ, タカオ; サクガワ, タカシ; カツキ, スナオ

    2005-01-01

    In recent years, several studies about electrical discharge plasma in supercritical carbon dioxide (CO2) have been carried out. One of the unique characteristics of supercritical fluid is a large density fluctuation near the critical point that can result in marked dramatic changes of thermal conductivity. Therefore, the electrical discharge plasma produced in supercritical fluid has unique features and reactions unlike those of normal plasma produced in gas phase. In our experiments, two typ...

  20. Generation of nanoparticles by spark discharge

    OpenAIRE

    Tabrizi, N.S.; Ullmann, M.; Vons, V.A.; Lafont, U.; Schmidt-Ott, A.

    2008-01-01

    The production of nanoparticles by microsecond spark discharge evaporation in inert gas is studied systematically applying transmission electron microscopy, mobility analysis and BET surface area measurement. The method of spark discharge is of special interest, because it is continuous, clean, extremely flexible with respect to material, and scale-up is possible. The particle size distributions are narrow and the mean primary particle size can be controlled via the energy per spark. Separate...

  1. Basic Studies of Distributed Discharge Limiters

    Science.gov (United States)

    2014-02-10

    radioactive sources , prior breakdown discharges, UV pre- excitation/pre-ionization, VUV radiation, multipactor, and field or triple-point emission; (2...o DC voltage bias effects and seed electron sources including radioactive sources , prior breakdown discharges, UV pre-excitation/pre-ionization, VUV ...found to be less susceptible to impurities and hydrogen Lyman-α emission remained dominant in the VUV regime. A MD- VUV source with a time averaged power

  2. Suprathermal electrons in a vacuum spark discharge

    Energy Technology Data Exchange (ETDEWEB)

    Bashutin, O. A., E-mail: boa308@mail.ru; Savjolov, A. S., E-mail: savjolov@plasma.mephi.ru [National Research Nuclear University MEPhI (Russian Federation)

    2016-04-15

    Results of experiments on the detection of suprathermal electron beams in the plasma of a highcurrent low-inductance vacuum spark by means of space-resolved spectral X-ray polarimetry are presented. It is shown that the observed polarization of bremsstrahlung may be caused by an ~100-keV electron beam propagating along the discharge axis from the pinching region toward the anode. The influence of the discharge initiation conditions on the parameters of the generated electron beams is analyzed.

  3. Plasma diagnostics discharge parameters and chemistry

    CERN Document Server

    Auciello, Orlando

    1989-01-01

    Plasma Diagnostics, Volume 1: Discharge Parameters and Chemistry covers seven chapters on the important diagnostic techniques for plasmas and details their use in particular applications. The book discusses optical diagnostic techniques for low pressure plasmas and plasma processing; plasma diagnostics for electrical discharge light sources; as well as Langmuir probes. The text also describes the mass spectroscopy of plasmas, microwave diagnostics, paramagnetic resonance diagnostics, and diagnostics in thermal plasma processing. Electrical engineers, nuclear engineers, microwave engineers, che

  4. Electric field in an AC dielectric barrier discharge overlapped with a nanosecond pulse discharge

    Science.gov (United States)

    Goldberg, Benjamin M.; Shkurenkov, Ivan; Adamovich, Igor V.; Lempert, Walter R.

    2016-08-01

    The effect of ns discharge pulses on the AC barrier discharge in hydrogen in plane-to-plane geometry is studied using time-resolved measurements of the electric field in the plasma. The AC discharge was operated at a pressure of 300 Torr at frequencies of 500 and 1750 Hz, with ns pulses generated when the AC voltage was near zero. The electric field vector is measured by ps four-wave mixing technique, which generates coherent IR signal proportional to the square of electric field. Absolute calibration was done using an electrostatic (sub-breakdown) field applied to the discharge electrodes, when no plasma was generated. The results are compared with one-dimensional kinetic modeling of the AC discharge and the nanosecond pulse discharge, predicting behavior of both individual micro-discharges and their cumulative effect on the electric field distribution in the electrode gap, using stochastic averaging based on the experimental micro-discharge temporal probability distribution during the AC period. Time evolution of the electric field in the AC discharge without ns pulses, controlled by a superposition of random micro-discharges, exhibits a nearly ‘flat top’ distribution with the maximum near breakdown threshold, reproduced quite well by kinetic modeling. Adding ns pulse discharges on top of the AC voltage waveform changes the AC discharge behavior in a dramatic way, inducing transition from random micro-discharges to a more regular, near-1D discharge. In this case, reproducible volumetric AC breakdown is produced at a well-defined moment after each ns pulse discharge. During the reproducible AC breakdown, the electric field in the plasma exhibits a sudden drop, which coincides in time with a well-defined current pulse. This trend is also predicted by the kinetic model. Analysis of kinetic modeling predictions shows that this effect is caused by large-volume ionization and neutralization of surface charges on the dielectrics by ns discharge pulses. The present

  5. River discharge estimation through MODIS data

    Science.gov (United States)

    Tarpanelli, Angelica; Brocca, Luca; Lacava, Teodosio; Faruolo, Mariapia; Melone, Florisa; Moramarco, Tommaso; Pergola, Nicola; Tramutoli, Valerio

    2011-11-01

    River discharge is an important quantity of the hydrologic cycle because it is essential for both scientific and operational applications related to water resources management and flood risk prevention. Streamflow measurements are sparse and for few sites along natural channels and, hence, they are not able to detect adequately the complexity of variation in surface water systems. Therefore, in recent years, the possibility to obtain river discharge estimates through remote sensing monitoring has received a great interest. In this context, the capability of the MODerate resolution Imaging Spectroradiometer (MODIS) for river discharge estimation is investigated here. Thanks to a very short revisiting time interval and a moderate spatial resolution (up to 250 m), MODIS has a significant potential for mapping flooded area extent and flow dynamics. Specifically, for the estimation of river discharge, the ratio of the MODIS channel 2 reflectance values between two pixels located within and outside the river is used. Time series of daily discharge between 2006 and 2010 measured at two gauging stations located along the Upper Tiber River basin (central Italy) are employed to test the procedure. The agreement between MODIS-derived and in situ discharge time series is found to be fairly good with correlation coefficient values close to 0.8.

  6. Glow discharge based device for solving mazes

    Energy Technology Data Exchange (ETDEWEB)

    Dubinov, Alexander E., E-mail: dubinov-ae@yandex.ru; Mironenko, Maxim S.; Selemir, Victor D. [Russian Federal Nuclear Center − All-Russian Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), Sarov, Nizhni Novgorod region 607188 (Russian Federation); Sarov Institute of Physics and Technology (SarFTI) of National Research Nuclear University “MEPhI,” Sarov, Nizhni Novgorod region 607188 (Russian Federation); Maksimov, Artem N.; Pylayev, Nikolay A. [Russian Federal Nuclear Center − All-Russian Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), Sarov, Nizhni Novgorod region 607188 (Russian Federation)

    2014-09-15

    A glow discharge based device for solving mazes has been designed and tested. The device consists of a gas discharge chamber and maze-transformer of radial-azimuth type. It allows changing of the maze pattern in a short period of time (within several minutes). The device has been tested with low pressure air. Once switched on, a glow discharge has been shown to find the shortest way through the maze from the very first attempt, even if there is a section with potential barrier for electrons on the way. It has been found that ionization waves (striations) can be excited in the maze along the length of the plasma channel. The dependancy of discharge voltage on the length of the optimal path through the maze has been measured. A reduction in discharge voltage with one or two potential barriers present has been found and explained. The dependency of the magnitude of discharge ignition voltage on the length of the optimal path through the maze has been measured. The reduction of the ignition voltage with the presence of one or two potential barriers has been observed and explained.

  7. Discharge state transition and cathode fall thickness evolution during chromium HiPIMS discharge

    Science.gov (United States)

    Zuo, Xiao; Ke, Peiling; Chen, Rende; Li, Xiaowei; Odén, Magnus; Wang, Aiying

    2017-08-01

    The temporal evolutions of target voltage and current waveforms under different pulse voltage and working pressure conditions were studied during Cr high power impulse magnetron sputtering discharges. Target voltage and current characteristics demonstrated that when the pulse width was set as 200 μs, HiPIMS discharge went through a four-stage sequence during each pulse, Townsend discharge, glow discharge, afterglow, and pulse-off stages. A discharge state transition in the glow discharge stage happened at high pulse voltage and working pressure conditions. Furthermore, the dependence of reduced cathode fall thickness pdc on pulse voltage, working pressure, and normalized current density j/p2 was presented. It was found that gas rarefaction leads to a change of relationship between pdc and j/p2. A noticeable increase of the cathode fall thickness caused by gas rarefaction has been found.

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

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Yu [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081 (China); Xie, Kan, E-mail: xiekan@bit.edu.cn [School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081 (China); Zhang, Yu; Ouyang, Jiting [School of Physics, Beijing Institute of Technology, Beijing 100081 (China)

    2016-02-15

    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 of 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.

  9. Performance of a large-scale barrier discharge plume improved by an upstream auxiliary barrier discharge

    Science.gov (United States)

    Li, Xuechen; Chu, Jingdi; Zhang, Qi; Zhang, Panpan; Jia, Pengying; Geng, Jinling

    2016-11-01

    Enhanced by an upstream auxiliary dielectric barrier discharge (ADBD), a transverse barrier discharge plume with a fairly large scale is generated downstream of a narrow slit. Electrical and optical characteristics are compared for the two discharges with and without the ADBD. Results indicate that the plume with the ADBD is longer, more uniform, and dissipates a higher power. Moreover, its inception voltage is much lower. High-speed imaging presents that the uniform plasma plume with the ADBD comprises a series of moving micro-discharge filaments in a glow regime, which are much smoother than those without the ADBD.

  10. Outcomes of very-low-birthweight infants after discharge with a discharge weight of 1500 grams.

    Science.gov (United States)

    Ahmadpour-Kacho, Mousa; Pasha, Yadollah Zahed; Aliabadi, Behdis Motevalli

    2012-04-01

    Discharge of very-low-birthweight (VLBW) neonates from hospital is an important issue and has a standard criterion worldwide. According to this criterion, VLBW infants will be discharged from hospital when weighing 1800-2100 g but in the newborn services at Amirkola Children's Hospital (ACH), VLBW neonates are discharged when reaching 1500 g. The aim of this study was to determine the safety of this policy. In this analytic-prospective study, 100 premature neonates with discharging weight (DW) of 1500 g and a control group of 150 neonates with DW of 1600-2500 g were included. Both groups showed similar socioeconomic, perinatal and postnatal conditions. They were admitted and treated in the newborn services at ACH. The outcome variables, including death after discharge, readmission and need for emergency visit for an acute problem up to 3 months after discharge, were studied. The information was analyzed by SPSS-16 software and a P-value discharge reached a significant difference between the two groups (31 in the case group vs 21 in the control group, P= 0.000), but there were no significant differences in the readmission rate and death after discharge (two deaths and 15 readmissions in the case group vs two deaths and 21 readmissions in the control group, P= 0.855) In order to decrease the need for emergency visits, we suggest a program of early hospital discharge with home nursing visits and neonatologist support. © 2011 The Authors. Pediatrics International © 2011 Japan Pediatric Society.

  11. Electric-discharge-pumped nitrogen ion laser

    Science.gov (United States)

    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.

  12. Patient participation in discharge planning conference

    Science.gov (United States)

    Bångsbo, Angela; Dunér, Anna; Lidén, Eva

    2014-01-01

    Introduction There is a need for individualized discharge planning to support frail older persons at hospital discharge. In this context, active participation on their behalf cannot be taken for granted. The aim of this study was to elucidate patient participation in discharge planning conferences, with a focus on frail older persons, supported by the theory of positioning described by Harré & van Langenhove. Methods The study was designed as a case study based on audio-recordings of multidisciplinary discharge planning conferences and interviews with health professionals elucidating their opinions on preconditions for patient participation in discharge planning. The analysis has been performed using qualitative content analysis and discourse analysis. Data collection took place during 2008–2009 and included 40 health professionals and 13 frail older persons in hospital or municipal settings. Results Findings revealed four different positions of participation, characterized by the older person's level of activity during the conference and his/her appearance as being reduced (patient) or whole (person). The positions varied dynamically from being an active person, passive person, active patient, or passive patient and the health professionals, next-of-kin, and the older persons themselves contributed to the positioning. Conclusions The findings showed how the institutional setting served as a purposeful structure or a confinement to patient participation. PMID:25411572

  13. Surface micro-discharges on spacecraft dielectrics

    Science.gov (United States)

    Balmain, K. G.; Cuchanski, M.; Kremer, P. C.

    1977-01-01

    Extensive measurements on Teflon and Kapton in a scanning electron microscope indicate the existence of a well-defined family of surface micro-discharges characteristic of the dielectric material. For a given small region exposed to the 16-20 kV electron beam, the strongest discharge pulses are similar in shape and amplitude. For Teflon, typical pulse durations are 2-3 ns, rise and fall times are sometimes as low as 0.2 ns, current amplitudes are approximately 100 mA flowing down to the pedestal and the pulses are unidirectional with no ringing. The use of a rapid-scan electron microscope with a secondary-electron imaging system reveals complex charge distributions resembling Lichtenberg figures on a supposedly flat homogeneous dielectric surface. These patterns undergo extensive alteration at each micro-discharge pulse and indicate that both the charging and discharging processes are highly nonuniform over the dielectric surface. The use of floodbeam causes the occurrence of a large-scale macro-discharges, in which a typical peak current is 40 A with a duration of 120 ns.

  14. Instabilities in inductive discharges in reactive gases

    Science.gov (United States)

    Chabert, Pascal

    2002-10-01

    High-density inductively coupled plasmas (ICP) are routinely used for etching in the microelectronics industry. Since there is a substantial voltage across the non-resonant inductive coil, a fraction of the discharge power is deposited capacitively. The real inductive discharge can therefore exist in two different modes: the capacitive mode (E mode), for low power, and the inductive mode (H mode), for high power. As the power is increased, transitions from capacitive to inductive modes (E-H transitions) are observed. Tuszewski (Journal of Applied Physics, 1996) found that when operating with reactive gases containing negative ions the transition can be unstable, and a wide range of powers exist where the discharge oscillates between higher and lower electron density states. Later, Lieberman and co-workers (Lieberman et al., Applied Physics Letters 1999, and Chabert et al. Plasma Sources Sci. and Technol. 2001) proposed a model of this instability, based on particle and energy balance, showing the crucial role of negative ions in the instability process. This paper will present recent experimental and theoretical work in this area. Oscillations in the unsaturated radical (CF and CF2 in a CF4 inductive discharge) concentrations were measured during the instability by time-resolved laser induced fluorescence, showing that neutral species dynamics can be significant. On the theoretical side, conditions for the stability of inductive discharges with electronegative gases were derived from the model.

  15. Relating river discharges to salinity changes

    Science.gov (United States)

    Xie, X.; Liu, W. T.

    2014-12-01

    New river discharge data are brought together with spacebased sea surface salinity measurements by Aquarius and SMOS to demonstrate the role of river discharge in salinity changes near three river mouths: the Mississippi, the Ganges, and the Amazon. The characteristics of the seasonal cycle and the year-to-year changes of the river runoff are described. Various versions of the satellite salinity data are compared. The relative roles of river discharge, surface water flux, and horizontal advection in changing surface salinity in regions near the river mouths are examined. Satellite measurements of SSS clearly track movements of the fresh water from river discharges. Besides the river discharge, E-P plays an important role in the seasonal salinity variation near the Ganges and Irrawaddy River mouths. For the Mississippi and Amazon river mouths, central and eastern ITCZ, E-P contributes very little to the salinity seasonal change. In the central and eastern ITCZ, contribution of advection to the salinity tendency is clearly identified. Both salinity and salinity tendency are dominated by semi-annual cycle in the Atlantic ITCZ between 5ºN to 9ºN, whereas annual cycle dominates at other latitudes.

  16. DISCHARGING MASTOID CAVITY: A CLINICAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    Praveen Kumar

    2015-05-01

    Full Text Available CONTEXT: A discharging mastoid cavity is a frustrating condition for both patient and surgeon and can occur after a canal wall down mastoidectomy operation . AIMS: To determine the percentage of patients having a discharging mastoid cavity and to establish the aetiological factors responsible for it . SETTING: Academic tertiary care referral institution . DESIGN: Prospective study MATERIALS AND METHODS: One hundred and sixty nine patie nts with chronic suppurative otitis media with cholesteatoma who underwent a canal wall down mastoidectomy were included in the study . These patients were regularly followed up to detect the occurrence of discharging mastoid cavity . RESULTS: Forty one ( 24 . 26% patients had a discharging mastoid cavity after a mean follow up of 4 . 2 years . The main causes were tympanic membrane perforation with exposed middle ear mucosa and open eustachian tube in thirty two patients ( 78 . 04% , followed by meatal stenosis in twenty five patients ( 60 . 97% and high facial ridge in twenty patients ( 48 . 78% . CONCLUSIONS: Tympanic membrane perforation with exposure of middle ear mucosa , meatal stenosis and a high facial ridge are important causes for a discharging mastoid cavity .

  17. Simulation of transition from Townsend mode to glow discharge mode in a helium dielectric barrier discharge at atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    Li Xue-Chen; Niu Dong-Ying; Xu Long-Fei; Jia Peng-Ying; Chang Yuan-Yuan

    2012-01-01

    The dielectric barrier discharge characteristics in helium at atmospheric pressure are simulated based on a one-dimensional fluid model.Under some discharge conditions,the results show that one discharge pulse per half voltage cycle usually appears when the amplitude of external voltage is low,while a glow-like discharge occurs at high voltage.For the one discharge pulse per half voltage cycle,the maximum of electron density appears near the anode at the beginning of the discharge,which corresponds to a Townsend discharge mode.The maxima of the electron density and the intensity of electric field appear in the vicinity of the cathode when the discharge current increases to some extent,which indicates the formation of a cathode-fall region.Therefore,the discharge has a transition from the Townsend mode to the glow discharge mode during one discharge pulse,which is consistent with previous experimental results.

  18. Discharge Education for Residents: A Study of Trainee Preparedness for Hospital Discharge.

    Science.gov (United States)

    Carnahan, Jennifer L; Fletcher, Kathlyn E

    2015-10-01

    Safe hospital discharges have become a major focus in the national discussion on transitions of care and care coordination. Education on the hospital discharge process is evolving as the needs of trainees are better understood. This study is a cross-sectional survey of residents in a Midwestern residency program about their confidence in safely discharging patients from the hospital, including how they have or have not learned to do so. An anonymous paper questionnaire was distributed to a convenience sample of interns and residents at a weekly meeting of the residency program. Most residents reported a general confidence in their abilities to safely discharge patients from the hospital; however, further probing revealed that their confidence breaks down when required to competently perform specific tasks of the discharge process such as activity restrictions or facilitation of home care. More than 50% of house staff surveyed responded that their education in many specific aspects of the discharge process are lacking. Interdisciplinary care education, and the discharge summary in particular, warrant further scrutiny as a care transition tool and means of teaching safe hospital discharge to trainees. We present a questionnaire that may serve useful as an anonymous tool to gauge residents' educational needs.

  19. The Experimental Investigations of Dielectric Barrier Discharge and Pulse Corona Discharge in Air Cleaning

    Institute of Scientific and Technical Information of China (English)

    左莉; 侯立安; 杨林松

    2003-01-01

    The dielectric barrier discharge (DBD) and pulse corona discharge(PCD) plasmagenerator was used to remove NH3, H2S, C7Hs etc. from atmosphere. The principle and charac-teristic of the two ways was discussed in the article. The test shows the result of PCD is betterthan that of DBD.

  20. Direct current dielectric barrier assistant discharge to get homogeneous plasma in capacitive coupled discharge

    Energy Technology Data Exchange (ETDEWEB)

    Du, Yinchang, E-mail: ycdu@mail.ustc.edu.cn [Modern Physics Department, University of Science and Technology of China, Hefei, Anhui 230026 (China); Max-Planck Institute for Extraterrestrial Physics, D-85748 Garching (Germany); Li, Yangfang [Max-Planck Institute for Extraterrestrial Physics, D-85748 Garching (Germany); Cao, Jinxiang; Liu, Yu; Wang, Jian; Zheng, Zhe [Modern Physics Department, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2014-06-15

    In this paper, we propose a method to get more homogeneous plasma in the geometrically asymmetric capacitive coupled plasma (CCP) discharge. The dielectric barrier discharge (DBD) is used for the auxiliary discharge system to improve the homogeneity of the geometrically asymmetric CCP discharge. The single Langmuir probe measurement shows that the DBD can increase the electron density in the low density volume, where the DBD electrodes are mounted, when the pressure is higher than 5 Pa. By this manner, we are able to improve the homogeneity of the plasma production and increase the overall density in the target volume. At last, the finite element simulation results show that the DC bias, applied to the DBD electrodes, can increase the homogeneity of the electron density in the CCP discharge. The simulation results show a good agreement with the experiment results.

  1. 42 CFR 418.26 - Discharge from hospice care.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Discharge from hospice care. 418.26 Section 418.26... (CONTINUED) MEDICARE PROGRAM HOSPICE CARE Eligibility, Election and Duration of Benefits § 418.26 Discharge from hospice care. (a) Reasons for discharge. A hospice may discharge a patient if— (1) The...

  2. Bloody nipple discharge in a 7-month-old boy.

    LENUS (Irish Health Repository)

    Zaid, Ahmed

    2011-10-01

    Isolated bloody nipple discharge is rare in infancy and is usually idiopathic. Discharge commonly resolves spontaneously, and ultrasonography is a useful diagnostic technique to detect the cause of discharge. The authors report a 7-month-old boy who presented with unilateral spontaneous bloody nipple discharge for 1 month without signs of infection or mass.

  3. Direct observation of laser guided corona discharges

    CERN Document Server

    Wang, Tie-Jun; Liu, Yaoxiang; Chen, Na; Liu, Yonghong; Ju, Jingjing; Sun, Haiyi; Wang, Cheng; Lu, Haihe; Liu, Jiansheng; Chin, See Leang; Li, Ruxin; Xu, Zhizhan

    2015-01-01

    Laser based lightning control holds a promising way to solve the problem of the long standing disaster of lightning strikes. But it is a challenging project due to insufficient understanding of the interaction between laser plasma channel and high voltage electric filed. In this work, a direct observation of laser guided corona discharge is reported. The high voltage corona discharge can be guided along laser plasma filament, and enhanced through the interaction with laser filaments. The fluorescence lifetime of laser filament guided corona discharge was measured to be several microseconds, which is 3 orders of magnitude longer than the fluorescence lifetime of laser filaments. This could be advantageous towards laser assisted leader development in the atmosphere.

  4. Paroxysmal discharges triggered by hearing spoken language.

    Science.gov (United States)

    Tsuzuki, H; Kasuga, I

    1978-04-01

    We examined the modality of EEG activation by various kinds of acoustic stimulation in a middle-aged Japanese female with epilepsy. Paroxysmal discharges were triggered in the right frontal area (F4) by verval stimulation. For the activation of EEG, concentration of attention on the stimulation was essential; therefore paroxysmal discharges were triggered most easily by verbal stimuli when someone spoke to the patient directly. Stronger responses than usual were triggered by specific words, and apparently reflected the interest and concern of the patient. The latency from stimulation to paroxysmal discharges ranged from 230 to 1,300 msec, suggesting that the responses may have been a function of the perception and recognition of acoustic stimuli. "Heard-word epilepsy" or "Angesprochene Epilepsie" is suggested in this case.

  5. Modelling of First Discharge in EAST Tokamak

    Institute of Scientific and Technical Information of China (English)

    LIU Chengyue; WU Bin; XIAO Bingjia; SHU Shuangbao

    2008-01-01

    An 1.5D equilibrium evolution code was used to model the time evolution of the first ohmic discharges in the EAST experiment. Good agreement between the simulation and the experimental results was obtained in the plasma current, major radius, electron temperature, loop voltage and poloidal field (PF) current for the entire duration of the discharge, which indicates that the code is highly reliable and will allow to further study the EAST discharge. At the same time, the code also simulates some important plasma parameters without experimental measured data yet, such as the plasma minor radius, central and edge safety factors, elongation and triangilarity, which are important in the analysis of EAST data.

  6. Determination of discharge during pulsating flow

    Science.gov (United States)

    Thompson, T.H.

    1968-01-01

    Pulsating flow in an open channel is a manifestation of unstable-flow conditions in which a series of translatory waves of perceptible magnitude develops and moves rapidly downstream. Pulsating flow is a matter of concern in the design and operation of steep-gradient channels. If it should occur at high stages in a channel designed for stable flow, the capacity of the channel may be inadequate at a discharge that is much smaller than that for which the channel was designed. If the overriding translatory wave carries an appreciable part of the total flow, conventional stream-gaging procedures cannot be used to determine the discharge; neither the conventional instrumentation nor conventional methodology is adequate. A method of determining the discharge during pulsating flow was tested in the Santa Anita Wash flood control channel in Arcadia, Calif., April 16, 1965. Observations of the dimensions and velocities of translatory waves were made during a period of controlled reservoir releases of about 100, 200, and 300 cfs (cubic feet per second). The method of computing discharge was based on (1) computation of the discharge in the overriding waves and (2) computation of the discharge in the shallow-depth, or overrun, part of the flow. Satisfactory results were obtained by this method. However, the procedure used-separating the flow into two components and then treating the shallow-depth component as though it were steady--has no theoretical basis. It is simply an expedient for use until laboratory investigation can provide a satisfactory analytical solution to the problem of computing discharge during pulsating flow. Sixteen months prior to the test in Santa Anita Wash, a robot camera had been designed .and programmed to obtain the data needed to compute discharge by the method described above. The photographic equipment had been installed in Haines Creek flood control channel in Los Angeles, Calif., but it had not been completely tested because of the infrequency of

  7. Excimer emission from cathode boundary layer discharges

    Science.gov (United States)

    Moselhy, Mohamed; Schoenbach, Karl H.

    2004-02-01

    The excimer emission from direct current glow discharges between a planar cathode and a ring-shaped anode of 0.75 and 1.5 mm diameter, respectively, separated by a gap of 250 μm, was studied in xenon and argon in a pressure range from 75 to 760 Torr. The thickness of the "cathode boundary layer" plasma, in the 100 μm range, and a discharge sustaining voltage of approximately 200 V, indicates that the discharge is restricted to the cathode fall and the negative glow. The radiant excimer emittance at 172 nm increases with pressure and reaches a value of 4 W/cm2 for atmospheric pressure operation in xenon. The maximum internal efficiency, however, decreases with pressure having highest values of 5% for 75 Torr operation. When the discharge current is reduced below a critical value, the discharge in xenon changes from an abnormal glow into a mode showing self-organization of the plasma. Also, the excimer spectrum changes from one with about equal contributions from the first and second continuum to one that is dominated by the second continuum emission. The xenon excimer emission intensity peaks at this discharge mode transition. In the case of argon, self-organization of the plasma was not seen, but the emission of the excimer radiation (128 nm) again shows a maximum at the transition from abnormal to normal glow. As was observed with xenon, the radiant emittance of argon increases with pressure, and the efficiency decreases. The maximum radiant emittance is 1.6 W/cm2 for argon at 600 Torr. The maximum internal efficiency is 2.5% at 200 Torr. The positive slope of the current-voltage characteristics at maximum excimer emission in both cases indicates the possibility of generating intense, large area, flat excimer lamps.

  8. Dielectric barrier discharge processing of aerospace materials

    Science.gov (United States)

    Scott, S. J.; Figgures, C. C.; Dixon, D. G.

    2004-08-01

    We report the use of atmospheric pressure, air based, dielectric barrier discharges (DBD) to treat materials commonly used in the aerospace industries. The material samples were processed using a test-bed of a conventional DBD configuration in which the sample formed one of the electrodes and was placed in close proximity to a ceramic electrode. The discharges generated a powerful, cold oxidizing environment which was able to remove organic contaminants, etch primer and paint layers, oxidize aluminium and roughen carbon fibre composites by the selective removal of resin.

  9. The Cellular Basis of a Corollary Discharge

    Science.gov (United States)

    Poulet, James F. A.; Hedwig, Berthold

    2006-01-01

    How do animals discriminate self-generated from external stimuli during behavior and prevent desensitization of their sensory pathways? A fundamental concept in neuroscience states that neural signals, termed corollary discharges or efference copies, are forwarded from motor to sensory areas. Neurons mediating these signals have proved difficult to identify. We show that a single, multisegmental interneuron is responsible for the pre- and postsynaptic inhibition of auditory neurons in singing crickets (Gryllus bimaculatus). Therefore, this neuron represents a corollary discharge interneuron that provides a neuronal basis for the central control of sensory responses.

  10. Early Home Supported Discharge of Stroke Patients:

    DEFF Research Database (Denmark)

    Larsen, Torben; Olsen, T. Skyhøj; Sørensen, Jan

    2006-01-01

    OBJECTIVES: A comprehensive and systematic assessment (HTA) of early home-supported discharge by a multidisciplinary team that plans, coordinates, and delivers care at home (EHSD) was undertaken and the results were compared with that of conventional rehabilitation at stroke units. METHODS......: A systematic literature search for randomized trials (RCTs) on "early supported discharge" was closed in April 2005. RCTs on EHSD without information on (i) death or institution at follow-up, (ii) change in Barthél Index, (iii) length of hospital stay, (iv) intensity of home rehabilitation, or (v) baseline...

  11. Pure Sulfur Discharges and Associated Spectra.

    Science.gov (United States)

    1978-10-01

    Graduate Engineering Physics G~~~ p~~~~ 9T8 7 Approved for public release; distribution unlimited . ~~~~ ~~~ - - -_ _ _ _ 0 Preface The author...the support of ARTO of A~~1L, the metalurgy lab and the machine shop at K.AFB NM have been essential in accomplishing the work presented here. A...Tables v Abstract vi I. INTRODUCTION 1 II. ELECTRONIC STRUCTURE, DISCHARGE PHYSICS , AND MOLECULAR PROCESSES Physical Characteristics 3 Discharge

  12. Micro-Discharge Micro-Thruster

    Science.gov (United States)

    2005-06-01

    breakdown at the maximum applied voltage (900 V) in Argon. The back side of the Paschen curve for Ar occurs at a pressure-length (P·d) product of less than...significant capacitance to ground from either lead (~ 100 nF). As small as this is, it had a profound effect on the discharge (see next section). A more space... effect in most thrusters even in the 100 Watt class. For a micro-discharge, even a stray coupling capacitance 50 pF observed for the power leads

  13. Acoustic field effects on a negative corona discharge

    Science.gov (United States)

    Bálek, R.; Červenka, M.; Pekárek, S.

    2014-06-01

    For a negative corona discharge under atmospheric pressure in different regimes, we investigated the effects of an acoustic field both on its electrical parameters and on the change in its visual appearance. We found that the application of an acoustic field on the true corona discharge, for particular currents, decreases the discharge voltage. The application of an acoustic field on the discharge in the filamentary streamer regime substantially extends the range of currents for which the discharge voltage remains more or less constant, i.e. it allows a substantial increase in the power delivered to the discharge. The application of an acoustic field on the discharge causes the discharge to spread within the discharge chamber and consequently, a highly reactive non-equilibrium plasma is created throughout the inter-electrode space. Finally, our experimental apparatus radiates almost no acoustic energy from the discharge chamber.

  14. Gas-discharge sources with charged particle emission from the plasma of glow discharge with a hollow cathode

    CERN Document Server

    Semenov, A P

    2001-01-01

    One studied properties of a magnetron discharge with a cold hollow and uncooled rod cathodes. One demonstrated the dominant effect of thermoelectron emission of a rod cathode heated in a discharge on characteristics of discharge and on emission properties of a gas-discharge plasma and the possibility pf a smooth transition of glow discharge to diffusion mode of arc discharge combustion. Paper describes sources of ions and electrons with improved physical and generalized design and engineering parameters. One shows the promise of the electrode structure of a hollow cathode magnetron discharge to be used as a source, in particular, of the atomic hydrogen and of atom flow of a working rod cathode

  15. The Electronic Discharge Letter Mobile App

    NARCIS (Netherlands)

    Lezcano, Leonardo; Ternier, Stefaan; Drachsler, Hendrik; Kalz, Marco; Specht, Marcus

    2013-01-01

    Lezcano, L., Ternier, S., Drachsler, H., Kalz, M., & Specht, M. (2013, September). The Electronic Discharge Letter Mobile App. In iProceedings of MEDICINE 2.0: 6th World Congress on Social Media, Mobile Apps, Internet/Web 2.0 (pp. 221-222). London, England. Retrieved from http://www.medicine20congre

  16. Scaling of a fast spherical discharge

    Energy Technology Data Exchange (ETDEWEB)

    Antsiferov, P. S., E-mail: Ants@isan.troitsk.ru; Dorokhin, L. A. [Russian Academy of Sciences, Institute of Spectroscopy (Russian Federation)

    2017-02-15

    The influence of the discharge cavity dimensions on the properties of the spherical plasma formed in a fast discharge was studied experimentally. The passage of a current pulse with an amplitude of 30–40 kA and a rise rate of ~10{sup 12} A/s (a fast discharge) through a spherical ceramic (Al{sub 2}O{sub 3}) cavity with an inner diameter of 11 mm filled with argon at a pressure of 80 Pa results in the formation of a 1- to 2-mm-diameter spherical plasma with an electron temperature of several tens of electronvolts and a density of 10{sup 18}–10{sup 19} cm{sup –3}. It is shown that an increase in the inner diameter of the discharge cavity from 11 to 21 mm leads to the fourfold increase in the formation time of the spherical plasma and a decrease in the average ion charge. A decrease in the cavity diameter to 7 mm makes the spherical plasma unstable.

  17. Generalized periodic discharges: Pathophysiology and clinical considerations

    NARCIS (Netherlands)

    van Putten, Michel Johannes Antonius Maria; Hofmeijer, Jeannette

    2015-01-01

    Generalized periodic discharges (GPDs) are commonly encountered in metabolic encephalopathy and cerebral hypoxia/ischemia. The clinical significance of this EEG pattern is indistinct, and it is unclear whether treatment with antiepileptic drugs is beneficial. In this study, we discuss potential

  18. Snowmelt contributions to discharge of the Ganges

    NARCIS (Netherlands)

    Siderius, C.; Biemans, H.; Wilthshire, A.; Rao, S.; Franssen, W.H.P.; Kumar, P.; Gosain, A.K.; Vliet, van A.; Collins, D.N.

    2013-01-01

    Himalayan headwaters supply large quantities of runoff derived from snowmelt and monsoon rainfall to the Ganges River. Actual snowmelt contribution to discharge in the Ganges remains conjectural under both present and future climatic conditions. As snowmelt is likely to be perturbed through climatic

  19. THE DISCHARGING EAR: A PRACTICAL APPROACH

    African Journals Online (AJOL)

    Enrique

    The substances that the ear may discharge include wax, pus, mucus, blood, cere- brospinal fluid (CSF) and ... ed with a history of trauma or skull base surgery, is likely to be CSF. Recurrent ... After assessing the patient's hearing with a tuning ...

  20. Generation of Nanoparticles by Spark Discharge

    NARCIS (Netherlands)

    Salman Tabrizi, N.

    2009-01-01

    Spark discharge is a method for producing nanoparticles from conductive materials. Besides the general advantages of nanoparticle synthesis in the gas phase, the method offers additional advantages like simplicity, compactness and versatility. The synthesis process is continuous and is performed at

  1. Estimating ground water discharge by hydrograph separation.

    Science.gov (United States)

    Hannula, Steven R; Esposito, Kenneth J; Chermak, John A; Runnells, Donald D; Keith, David C; Hall, Larry E

    2003-01-01

    Iron Mountain is located in the West Shasta Mining District in California. An investigation of the generation of acid rock drainage and metals loading to Boulder Creek at Iron Mountain was conducted. As part of that investigation, a hydrograph separation technique was used to determine the contribution of ground water to total flow in Boulder Creek. During high-flow storm events in the winter months, peak flow in Boulder Creek can exceed 22.7 m3/sec, and comprises surface runoff, interflow, and ground water discharge. A hydrograph separation technique was used to estimate ground water discharge into Boulder Creek during high-flow conditions. Total ground water discharge to the creek approaches 0.31 m3/sec during the high-flow season. The hydrograph separation technique combined with an extensive field data set provided reasonable estimates of ground water discharge. These estimates are useful for other investigations, such as determining a corresponding metals load from the metal-rich ground water found at Iron Mountain and thus contributing to remedial alternatives.

  2. Prosthesis fabrication using electrical discharge machining.

    Science.gov (United States)

    Van Roekel, N B

    1992-01-01

    Fixed-removable implant prostheses provide solutions for some of the problems associated with implant dentistry, especially in the maxilla. The technique for using electrical discharge machining to create a precise passive fit between the substructure bar and the removable suprastructure is presented. The advantages, disadvantages, and complications associated with this type of prosthesis are discussed.

  3. MICRO ELECTRICAL DISCHARGE MACHINING DEPOSITION IN AIR

    Institute of Scientific and Technical Information of China (English)

    JIN Baidong; ZHAO Wansheng; WANG Zhenlong; CAO Guohui

    2006-01-01

    A new deposition method is described using micro electrical discharge machining (EDM)to deposit tool electrode material on workpiece in air. The basic principles of micro electrical discharge deposition (EDD) are analyzed and the realized conditions are predicted. With an ordinary EDM shaping machine, brass as the electrode, high-speed steel as the workpiece, a lot of experiments are carried out on micro EDD systematically and thoroughly. The effects of major processing parameters, such as the discharge current, discharge duration, pulse interval and working medium, are obtained. As a result, a micro cylinder with 0.19 mm in diameter and 7.35 mm in height is deposited.By exchanging the polarities of the electrode and workpiece the micro cylinder can be removed selectively. So the reversible machining of deposition and removal is achieved, which breaks through the constraint of traditional EDM. Measurements show that the deposited material is compact and close to workpiece base, whose components depend on the tool electrode material.

  4. Monitor For Electrical-Discharge Machining

    Science.gov (United States)

    Burley, Richard K.

    1993-01-01

    Circuit monitors electrical-discharge-machining (EDM) process to detect and prevent abnormal arcing, which can produce unacceptable "burn" marks on workpiece. When voltage between EDM electrode and workpiece behaves in manner indicative of abnormal arcing, relay made to switch off EDM power, which remains off until operator attends to EDM setup and resets monitor.

  5. Electrical-Discharge Machining Of Curved Passages

    Science.gov (United States)

    Guirguis, Kamal S.

    1993-01-01

    Electrical-discharge machining (EDM) used to cut deep hole with bends. EDM process done with articulating segmented electrode. Originally straight, electrode curved as it penetrates part, forming long, smoothly curving hole. After hole cut, honed with slurry to remove thin layer of recast metal created by EDM. Breakage of tools, hand deburring, and drilling debris eliminated.

  6. Six-Axis Electrical-Discharge Machine

    Science.gov (United States)

    Werner, A. R.

    1983-01-01

    Electrical discharge machine (EDM) of unusual versitility made by conversion of radial drill. Drilling head is replaced by ram that holds and positions electrode. Tank and recirculation system for coolant are added. EDM has six independent motions and drastically reduced cost of manufacturing. New applications are constantly being found.

  7. Dielectric barrier discharge source for supersonic beams

    Energy Technology Data Exchange (ETDEWEB)

    Luria, K.; Lavie, N.; Even, U. [Sackler School of Chemistry, Tel Aviv University, Tel Aviv 69978 (Israel)

    2009-10-15

    We present a new excitation source for pulsed supersonic beams. The excitation is based on dielectric barrier discharge in the beam. It produces cold beams of metastable atoms, dissociated neutral atoms from molecular precursors, and both positive and negative ions with high efficiency and reliability.

  8. The Electrostatic Environments of Mars: Atmospheric Discharges

    Science.gov (United States)

    Calle, Carlos I.; Mackey, Paul J.; Johansen, Michael R.; Hogue, Michael D.; Phillips, James, III; Cox, Rachel E.

    2016-01-01

    The electrostatic environment on Mars is controlled by its ever present atmospheric dust. Dust devils and dust storms tribocharge this dust. Theoretical studies predict that lightning and/or glow discharges should be present on Mars, but none have been directly observed. Experiments are planned to shed light on this issue.

  9. From submarine to lacustrine groundwater discharge

    Science.gov (United States)

    Lewandowski, Jörg; Meinikmann, Karin; Pöschke, Franziska; Nützmann, Gunnar; Rosenberry, Donald O.

    2017-01-01

    Submarine groundwater discharge (SGD) and its role in marine nutrient cycling are well known since the last decade. The freshwater equivalent, lacustrine groundwater discharge (LGD), is often still disregarded, although first reports of LGD are more than 50 years old. We identify nine different reasons why groundwater has long been disregarded in both freshwater and marine environments such as invisibility of groundwater discharge, the size of the interface and its difficult accessibility. Although there are some fundamental differences in the hydrology of SGD and LGD, caused primarily by seawater recirculation that occurs only in cases of SGD, there are also a lot of similarities such as a focusing of discharge to near-shore areas. Nutrient concentrations in groundwater near the groundwater–surface water interface might be anthropogenically enriched. Due to spatial heterogeneity of aquifer characteristics and biogeochemical processes, the quantification of groundwater-borne nutrient loads is challenging. Both nitrogen and phosphorus might be mobile in near-shore aquifers and in a lot of case studies large groundwater-borne nutrient loads have been reported.

  10. The Electronic Discharge Letter Mobile App

    NARCIS (Netherlands)

    Lezcano, Leonardo; Ternier, Stefaan; Drachsler, Hendrik; Kalz, Marco; Specht, Marcus

    2013-01-01

    Lezcano, L., Ternier, S., Drachsler, H., Kalz, M., & Specht, M. (2013, September). The Electronic Discharge Letter Mobile App. In iProceedings of MEDICINE 2.0: 6th World Congress on Social Media, Mobile Apps, Internet/Web 2.0 (pp. 221-222). London, England. Retrieved from

  11. Generation of Nanoparticles by Spark Discharge

    NARCIS (Netherlands)

    Salman Tabrizi, N.

    2009-01-01

    Spark discharge is a method for producing nanoparticles from conductive materials. Besides the general advantages of nanoparticle synthesis in the gas phase, the method offers additional advantages like simplicity, compactness and versatility. The synthesis process is continuous and is performed at

  12. Electrostatic Discharge Properties of Irradiated Nanocomposites

    Science.gov (United States)

    2009-03-01

    xiii ESD Electrostatic Discharge Ext External Configuration with 200 gsm Ni, of Composite Group Two GA Genetic Algorithm GEO Geosynchronous...materials similar to those tested in this experiment are exposed throughout a life-cycle was simulated using the High Voltage Engineering, Europa

  13. Experimental studies of ITER demonstration discharges

    NARCIS (Netherlands)

    Sips, A.C.C.; Casper, T. A.; Doyle, E. J.; Giruzzi, G.; Gribov, Y.; Hobirk, J.; Hogeweij, G. M. D.; Horton, L. D.; Hubbard, A. E.; Hutchinson, I.; Ide, S.; Isayama, A.; Imbeaux, F.; Jackson, G. L.; Kamada, Y.; Kessel, C.; Kochl, F.; Lomas, P.; Litaudon, X.; Luce, T. C.; Marmar, E.; Mattei, M.; Nunes, I.; Oyama, N.; Parail, V.; Portone, A.; Saibene, G.; Sartori, R.; Stober, J. K.; Suzuki, T.; Wolfe, S. M.

    2009-01-01

    Key parts of the ITER scenarios are determined by the capability of the proposed poloidal field (PF) coil set. They include the plasma breakdown at low loop voltage, the current rise phase, the performance during the flat top (FT) phase and a ramp down of the plasma. The ITER discharge evolution has

  14. Partial discharge transients: The field theoretical approach

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson; Crichton, George C

    1998-01-01

    Up until the mid-1980s the theory of partial discharge transients was essentially static. This situation had arisen because of the fixation with the concept of void capacitance and the use of circuit theory to address what is in essence a field problem. Pedersen rejected this approach and instead...

  15. Partial discharges in ellipsoidal and spheroidal voids

    DEFF Research Database (Denmark)

    Crichton, George C; Karlsson, P. W.; Pedersen, Aage

    1989-01-01

    Transients associated with partial discharges in voids can be described in terms of the charges induced on the terminal electrodes of the system. The relationship between the induced charge and the properties which are usually measured is discussed. The method is illustrated by applying it to a s...

  16. Metal hydrides studied in gas discharge tube

    Science.gov (United States)

    Bozhinova, I.; Kolev, S.; Popov, Tsv.; Pashov, A.; Dimitrova, M.

    2016-05-01

    A novel construction of gas discharge tube has been tested for production of high densities of metal hydrydes. Its performance turned out to be comparable with the existing sources of the same type and even better. First results of the tests on NiH are reported and critically analysed. Plans for future modifiaction of the construction and application of the tube are discussed.

  17. Granular discharge rate for submerged hoppers

    Directory of Open Access Journals (Sweden)

    T. J. Wilson

    2014-10-01

    Full Text Available The discharge of spherical grains from a hole in the bottom of a right circular cylinder is measured with the entire system underwater. We find that the discharge rate depends on filling height, in contrast to the well-known case of dry non-cohesive grains. It is further surprising that the rate increases up to about twenty five percent, as the hopper empties and the granular pressure head decreases. For deep filling, where the discharge rate is constant, we measure the behavior as a function of both grain and hole diameters. The discharge rate scale is set by the product of hole area and the terminal falling speed of isolated grains. But there is a small-hole cutoff of about two and half grain diameters, which is larger than the analogous cutoff in the Beverloo equation for dry grains. Received: 11 September 2014, Accepted: 10 October 2014; Reviewed by: L. Staron, CNRS, Universite Pierre et Marie Curie, Institut Le Rond d'Alembert, Paris, France; Edited by: L. A. Pugnaloni; DOI: http://dx.doi.org/10.4279/PIP.060009 Cite as: T J Wilson, C R Pfeifer, N Meysingier, D J Durian, Papers in Physics 6, 060009 (2014

  18. Analytical calculations of anode plasma position in high-voltage discharge range in case of auxiliary discharge firing

    OpenAIRE

    Melnyk, Igor V.; Tugay, S. B.

    2012-01-01

    We consider the mathematical model of triode high-voltage glow discharge range in case of auxiliary discharge firing. On a basis of analysis of elementary processes of charged particles interaction in a discharge range we obtain analytical relation, which allows to obtain the anode plasma position with regard to the cathode. Obtained results can be used for analysis of analysis of energy balance in a discharge range and self-maintained electron-ion optics of high voltage glow discharge electr...

  19. The Impact of Revised Discharge Instructions on Patient Satisfaction

    Directory of Open Access Journals (Sweden)

    Heather Markey Waniga RN, MSN

    2016-09-01

    Full Text Available Introduction: The impact of discharge instructions on a patient’s experience is not fully understood. This research explored whether nurse- and physician-generated discharge instructions had a positive effect on patient perceptions regarding their discharge experience. Methods: We compared Press Ganey discharge-related patient satisfaction scores for the year prior to and the year subsequent to implementing revised discharge instructions for all patients admitted to a 180-bed community-based hospital. Results: Following the implementation of our revised discharge instructions, patient satisfaction significantly improved (84.7% vs 83%, P < .01. Patients responded that they felt ready for discharge (86.6% vs 84.9%, P = .01 and were satisfied with instructions for home care (87.8% vs 85.3%, P < .01. Discussion: This study finds that a novel discharge instruction set produced by both the nursing and physician staff may improve patient perceptions with the discharge process.

  20. Discharging dynamics in an electrolytic cell

    Science.gov (United States)

    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

  1. Ignition Features of Plasma-Beam Discharge in Gas-Discharge Electron Gun Operation

    Directory of Open Access Journals (Sweden)

    Valery A. Tutyk

    2013-01-01

    Full Text Available The current paper presents the results of experimental researches to determine the mode features of plasma-beam discharge (PBD generation by an electron beam injected by a low-vacuum gasdischarge electron gun (LGEG with the cold cathode and hollow anode on the basis of the high-voltage glow discharge and in the range of helium pressure of P ? 10 ÷ 130 Pa. The PBD boundaries and their dependences on parameters of an electron beam are found. The influence of PBD on parameters of low-vacuum gas-discharge electron gun is revealed. It causes an avalanche increase of electron beam current and burning of plasma-beam discharge in the whole space of the vacuum chamber volume and generation of electromagnetic radiation is revealed. Achieved results will be used for implementation of various vacuum technologies in the medium of reaction gas and generated electromagnetic radiation.

  2. ANALISA PENGARUH PERIODIK CHARGING DAN DISCHARGING PADA WAKTU CHARGING DAN DISCHARGING DARI METAL HYDRIDE REACTOR (MHR

    Directory of Open Access Journals (Sweden)

    Taurista Perdana Syawitri

    2015-01-01

    Full Text Available Perpindahan panas merupakan faktor penting yang mempengaruhi kinerja tangki penyimpanan hydrogen dalam bentuk metal hydride. Penelitian sebelumnya menyimpulkan bahwa penambahan sejumlah kecil metal foam pada interior metal hydride reactor (MHR merupakan cara yang efektif untuk meningkatkan perpindahan panas pada reaktor, sehingga mengurangi waktu charging. Namun, proses charging dan discharging MHR dilakukan secara terpisah dalam studi ini. Oleh karena itu, penelitian ini menyimulasikan model 2-D axisymmetric menggunakan software COMSOL untuk menginvestigasi pengaruh dari periodik charging dan discharging dari MHR yang mengandung metal foam dengan fraksi volume tertentu. Hasil simulasi menunjukkan bahwa model saat ini mempunyai hasil yang sesuai dengan hasil yang ditunjukkan di dalam literatur. Selain itu, ditemukan bahwa terdapat nilai optimum dari fraksi volume metal foam di setiap proses charging dan proses discharging yang memberikan waktu charging dan discharging lebih pendek.

  3. Influence of gas discharge parameters on emissions from a dielectric barrier discharge excited argon excimer lamp

    OpenAIRE

    2011-01-01

    A dielectric barrier discharge excited neutral argon (Ar I) excimer lamp has been developed and characterised. The aim of this study was to develop an excimer lamp operating at atmospheric pressure that can replace mercury lamps and vacuum equipment used in the sterilisation of medical equipment and in the food industry. The effects of discharge gas pressure, flow rate, excitation frequency and pulse width on the intensity of the Ar I vacuum ultraviolet (VUV) emission at 126 nm and near infra...

  4. Electron assisted glow discharges for conditioning fusion tokamak devices

    Science.gov (United States)

    Schaubel, K. M.; Jackson, G. L.

    1989-08-01

    Glow discharge conditioning of tokamaks with graphite plasma-facing surfaces has been used to reduce impurities and obtain density control of the plasma discharge. However, a major operational disadvantage of glow conditioning is the high pressure required to initiate the glow discharge, e.g., approx. 70 mTorr for helium in DIII-D, which requires isolating auxiliary components that can not tolerate the high pressure. An electron-gun assisted glow discharge can lower breakdown pressure, possibly eliminating the necessity of isolating these auxiliary systems during glow discharge conditioning and allowing glow discharge operation at lower pressures.

  5. Discharge current modes of high power impulse magnetron sputtering

    Directory of Open Access Journals (Sweden)

    Zhongzhen Wu

    2015-09-01

    Full Text Available 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.

  6. Atmospheric Pressure Glow Discharge with Liquid Electrode

    Science.gov (United States)

    Tochikubo, Fumiyoshi

    2013-09-01

    Nonthermal atmospheric pressure plasmas in contact with liquid are widely studied aiming variety of plasma applications. DC glow discharge with liquid electrode is an easy method to obtain simple and stable plasma-liquid interface. When we focus attention on liquid-phase reaction, the discharge system is considered as electrolysis with plasma electrode. The plasma electrode will supply electrons and positive ions to the liquid surface in a different way from the conventional metal electrode. However, the phenomena at plasma-liquid interface have not been understood well. In this work, we studied physical and chemical effect in liquid induced by dc atmospheric pressure glow discharge with liquid electrode. The experiment was carried out using H-shaped Hoffman electrolysis apparatus filled with electrolyte, to separate the anodic and cathodic reactions. Two nozzle electrodes made of stainless steel are set about 2 mm above the liquid surface. By applying a dc voltage between the nozzle electrodes, dc glow discharges as plasma electrodes are generated in contact with liquid. As electrolyte, we used aqueous solutions of NaCl, Na2SO4, AgNO3 and HAuCl4. AgNO3 and HAuCl4 are to discuss the reduction process of metal ions for synthesis of nanoparticles (NPs). OH radical generation yield in liquid was measured by chemical probe method using terephthalic acid. Discharge-induced liquid flow was visualized by Schlieren method. Electron irradiation to liquid surface (plasma cathode) generated OH- and OH radical in liquid while positive ion irradiation (plasma anode) generated H+ and OH radical. The generation efficiency of OH radical was better with plasma anode. Both Ag NPs in AgNO3 and Au NPs in HAuCl4 were synthesized with plasma cathode while only Au NPs were generated with plasma anode. Possible reaction process is qualitatively discussed. The discharge-induced liquid flow such as convection pattern was strongly influenced by the gas flow on the liquid surface. This work

  7. Numerical Simulation of Unsteady Discharge Flow with Fluctuation in Positive Discharge Blower

    Institute of Scientific and Technical Information of China (English)

    LIU Zhengxian; WANG Dou; XU Lianhuan

    2009-01-01

    The operating performance of positive discharge blower/s markedly influenced by the pulsation of the discharge flow, but difficult to be measured with experimental methods. The internal and discharge flow of positive discharge blower with involute type three-lobe are numerically investigated, both in air cooling and countercurrent cooling conditions by means of computational fluid dynamics (CFD). The unsteady compressible flow equations are solved using RNG κ-ε turbulent model. The finite difference method and the second order upwind difference scheme are applied into discrete equations. In the numerical simulation, the dynamic mesh techniques are used to approach the rotating displacement of cell cubage and the alterability of inlet, outlet flow area. The non-uniform mesh is applied to the rotor-stator coupled area. The reliability of the numerical method is verified by simulating the inner flow and comparing with the semi-empirical theory. The flow flux curves and the distributing of velocity vector showed obvious vortex motion in all the discharge process, both in air cooling and countercurrent cooling conditions. These vortexes with different positions, intension and numbers at different rotating angles have remarkable influences on the discharge flux. For air cooling, the vortex produced a second pulsation with big-amplitude in a cycle, and led to the early appearance of maximum of backflow. For countercurrent cooling, the frequency of pulsation increased due to the pre-inflow, but the hackflow at the outlet is prevented, also the pulsation strength has greatly decreased.

  8. RFID reader immunity test against electrostatic discharge

    Directory of Open Access Journals (Sweden)

    Pospisilik Martin

    2016-01-01

    Full Text Available This paper provides a description of an immunity test against the electrostatic discharge according to the standard EN 61000-4-2 that was applied to an RFID reader. The RFID reader was primarily developed for access systems, employing the on-board recognition of the RFID tags. The results obtained by the test are described hereby as well as the discussion on the security of this solution. The results of this experiment are beneficial for the developers of RFID devices, as these devices are endangered by the electrostatic discharge brought by their users. The hereby described results also shown a security hole in a simple access system based on the RFID technology. Details can be found in the paper.

  9. Structure formation of atmospheric pressure discharge

    Science.gov (United States)

    Medvedev, Alexey E.

    2016-02-01

    In this paper it is shown, by analyzing the results of experimental studies, that the outer boundary of the atmospheric pressure discharge pinch is determined by the condition of equality of plasma flows based on the thermal and electric field energy. In most cases, the number of charged particles coming from near-electrode zones is sufficient to compensate for losses in the discharge bulk. At large currents and enhanced heating, plasma is in the diffusion mode of losses, with recombination of charged particles at the pinch boundary. 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.

  10. Varactor with integrated micro-discharge source

    Science.gov (United States)

    Elizondo-Decanini, Juan M.; Manginell, Ronald P.; Moorman, Matthew W.

    2016-10-18

    An apparatus that includes a varactor element and an integrated micro-discharge source is disclosed herein. In a general embodiment, the apparatus includes at least one np junction and at least one voltage source that is configured to apply voltage across the np junction. The apparatus further includes an aperture that extends through the np junction. When the voltage is applied across the np junction, gas in the aperture is ionized, forming a plasma, in turn causing a micro-discharge (of light, charge particles, and space charge) to occur. The light (charge particles, and space charge) impinges upon the surface of the np junction exposed in the aperture, thereby altering capacitance of the np junction. When used within an oscillator circuit, the effect of the plasma on the np-junction extends the capacitance changes of the np-junction and extends the oscillator frequency range in ways not possible by a conventional voltage controlled oscillator (VCO).

  11. Sound spectrum of a pulsating optical discharge

    Energy Technology Data Exchange (ETDEWEB)

    Grachev, G N; Smirnov, A L; Tishchenko, V N [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Dmitriev, A K; Miroshnichenko, I B [Novosibirsk State Technical University (Russian Federation)

    2016-02-28

    A spectrum of sound of an optical discharge generated by a repetitively pulsed (RP) laser radiation has been investigated. The parameters of laser radiation are determined at which the spectrum of sound may contains either many lines, or the main line at the pulse repetition rate and several weaker overtones, or a single line. The spectrum of sound produced by trains of RP radiation comprises the line (and overtones) at the repetition rate of train sequences and the line at the repetition rate of pulses in trains. A CO{sub 2} laser with the pulse repetition rate of f ≈ 3 – 180 kHz and the average power of up to 2 W was used in the experiments. (optical discharges)

  12. Varactor with integrated micro-discharge source

    Energy Technology Data Exchange (ETDEWEB)

    Elizondo-Decanini, Juan M.; Manginell, Ronald P.; Moorman, Matthew W.

    2016-10-18

    An apparatus that includes a varactor element and an integrated micro-discharge source is disclosed herein. In a general embodiment, the apparatus includes at least one np junction and at least one voltage source that is configured to apply voltage across the np junction. The apparatus further includes an aperture that extends through the np junction. When the voltage is applied across the np junction, gas in the aperture is ionized, forming a plasma, in turn causing a micro-discharge (of light, charge particles, and space charge) to occur. The light (charge particles, and space charge) impinges upon the surface of the np junction exposed in the aperture, thereby altering capacitance of the np junction. When used within an oscillator circuit, the effect of the plasma on the np-junction extends the capacitance changes of the np-junction and extends the oscillator frequency range in ways not possible by a conventional voltage controlled oscillator (VCO).

  13. Similarity criterion of flood discharge atomization

    Institute of Scientific and Technical Information of China (English)

    Zhou Hui; Wu Shiqiang; Chen Huiling; Zhou Jie; Wu Xiufeng

    2008-01-01

    By combining the results of prototype observation of flood discharge atomization at the Wujiangdu Hydropower Station, and by adopting the serial model test method, the model scale effect was examined, the influences of the Reynolds and Weber numbers of water flow on the rain intensity of flood discharge atomization were analyzed and a rain intensity conversion relation was established. It is demonstrated that the level of atomization follows the geometric similarity relations and it is possible to ignore the influence of the surface tension of the flow when the Weber number is greater than 500. Despite limitations such as incomplete data sets, it is undoubtedly helpful to study the scale effect of atomization flow, and it is beneficial to identify the rules of the model test results in order to extrapolate to prototype prediction.

  14. Early supported discharge following mild stroke

    DEFF Research Database (Denmark)

    Lou, Stina; Carstensen, Kathrine; Møldrup, Marie;

    2016-01-01

    BACKGROUND: Early supported discharge (ESD) allows mild-to-moderate stroke patients to return home as soon as possible and continue rehabilitation at their own pace in familiar surroundings. Thus, the main responsibility for continued rehabilitation is in the hands of patients and their partners......, who must collaborate to adjust to poststroke everyday life. However, couples' joint experiences of stroke, early discharge and rehabilitation at home remain minimally investigated. AIM: To investigate how mild stroke patients' and their partners' experience and manage everyday life in a context of ESD....... METHODS: We conducted qualitative interviews with a purposive sample of 22 ESD patients and 18 partners. Interviews were conducted 3-6 weeks after stroke, and we used thematic analysis to analyse the data. FINDINGS: The analysis identified three themes. First, 'Home as a healing place' involved...

  15. Studying barrier-discharge-stimulated plasmachemical reactions

    Science.gov (United States)

    Malanichev, V. E.; Malashin, M. V.; Moshkunov, S. I.; Nebogatkin, S. V.; Khomich, V. Yu.; Shmelev, V. M.

    2017-05-01

    Barrier-discharge stimulation of chemical reactions has been studied in the case of methane oxidation by atmospheric oxygen with the formation of carbon monoxide and hydrogen. Experiments in a plasmachemical reactor demonstrated the possibility of increasing the yield of synthesis gas (syngas) by means of plasma pretreatment of the initial mixture of air and methane in a 7: 1 ratio at atmospheric pressure. The output-gas composition was determined by gas chromatography. It is established that the plasma-discharge treatment of the initial gas mixture leads to a 15% increase in the amount of syngas at the reactor output and increases the reaction selectivity with respect to hydrogen and carbon monoxide by 3.2 and 6.5%, respectively.

  16. On ULF Signatures of Lightning Discharges

    Science.gov (United States)

    Bösinger, T.; Shalimov, S. L.

    2008-06-01

    Recent works on magnetic signatures due to distant lightning discharges are reviewed. Emphasis is laid on magnetic signatures in the ULF range (in the old definition from less than 1 mHz up to 1 Hz), that is in the frequency range below the Schumann resonance. These signatures are known to be of importance for the excitation of the ionospheric Alfvén resonator (IAR) which works only at night time conditions. This emphasizes the difference between night and day time ULF signatures of lightning. The IAR forms a link between the atmosphere and magnetosphere. Similarities and differences of this link in the VLF (Trimpi effect) and ULF range are worked out. A search for a unique signature of sprite-associated positive cloud-to-ground (+CG) lightning discharges ended with a negative result. In this context, however, a new model of lightning-associated induced mesospheric currents was built. Depending on mesospheric condition it can produce magnetic signatures in the entire frequency range from VLF, ELF to ULF. In the latter case it can explain signatures known as the Ultra Slow Tail of +CG lightning discharges. A current problem on the magnetic background noise intensity has been solved by taking more seriously the contribution of +CG lightning discharges to the overall background noise. Their low occurrence rate is more than compensated by their large and long lasting continuing currents. By superposed epoch analysis it could be shown that the ULF response to -CG is one to two orders smaller that in case of +CG with similar peak current values of the return stroke.

  17. Methane conversion to hydrocarbons by double discharge

    Directory of Open Access Journals (Sweden)

    A. M. Ghorbanzadeh

    2004-12-01

    Full Text Available   Methane conversion to higher hydrocarbons by pulsed glow discharge at the atmospheric pressure was investigated. The energy efficiency up to 10 % was obtained which is higher than any value ever published for nonequilibrium plasma conversion of pure methame. This method has a potential for development and it is expected that the energy efficiency will be improved further if the plasma parameters are optimized.

  18. Device Stores and Discharges Metered Fluid

    Science.gov (United States)

    Hooper, S. L.; Setzer, D.

    1983-01-01

    Hand-held container accepts measured amount of liquid from pressurized supply. Supply pressure drives spring-loaded piston that stores enough mechanical energy to discharge measured liquid into another container. Original application of container was to rehydrate sterilized pre-packaged food in zerogravity environment of space vehicles. Possible terrestrial applicatios include dispensing of toxic fluids or metering of fluids for household, commercial or laboratory uses.

  19. Stream discharge measurements under ice cover

    Science.gov (United States)

    Noland, K. Michael; Jacobson, Nathan D.

    2000-01-01

    This training presentation shows procedures used by the U.S. Geological Survey to measure streamflow when streams are covered by ice. Although 'Ice Measurements' are generally more difficult to make than open-water measurements and are often made under uncomfortable conditions it is very important that ice measurements be made regularly during the winter. This is because a large part of many winter discharge records depend on such measurements.

  20. Electrical-Discharge Machining With Additional Axis

    Science.gov (United States)

    Malinzak, Roger M.; Booth, Gary N.

    1991-01-01

    Proposed electrical-discharge-machining (EDM) apparatus uses moveable vertical wire as electrode. Wire positionable horizontally along one axis as it slides vertically past workpiece. Workpiece indexed in rotation about horizontal axis. Because of symmetry of parts, process used to make two such parts at a time by defining boundary between them. Advantages: cost of material reduced, imparts less residual stress to workpiece, and less time spent machining each part when parts produced in such symmetrical pairs.

  1. Preset Electrodes for Electrical-Discharge Machining

    Science.gov (United States)

    Coker, Bill E.

    1987-01-01

    New electrode holder for electrical-discharge machining (EDM) provides for repeatable loading and setting of many electrodes. New holder is rotating-index tool carrying six, eight, or more electrodes. Before use, all electrodes set with aid of ring surrounding tool, and locked in position with screws. When electrode replaced, EDM operator pulls spring-loaded pin on tool so it rotates about center pin. Fresh electrode then rotated into position against workpiece.

  2. Microbiology of discharging ears in Ethiopia

    Institute of Scientific and Technical Information of China (English)

    Getachew Tesfaye; Daniel Asrat; Yimtubezinash Woldeamanuel; Messele Gizaw

    2009-01-01

    Objectives:To isolate and identify the bacterial etiologic agents,including their antibiotic susceptibility pat-tern isolated from patients with discharging ear infections.Methods:Between September 2006 and February 2007,178 patients with discharging ear visiting ENT clinics of St.Paul and Tikur Anbessa University Hospi-tals Addis Ababa,Ethiopia were investigated.Results:Of the patients investigated,52.8% were males and 47.2% were females resulting in an overall male to female ratio of 1.1:1.Ear discharge was the commonest clinical finding followed by hearing problem (91.2%),otalgia (ear pain)(74.7%),fever (17.9%)and itching of external ear (5.1%).S.aureus accounted for 30.2% of the total isolates followed by Proteus ssp. (P.mirabilis,P.vulgaris )(25.4%),and P.aeruginosa (13.4%).Both gram positive and negative bac-teria isolated from ear infections showed low resistance rates to most antimicrobial agents tested.Overall ceftri-axone and ciprofloxacin were the most effective drugs when compared to other drugs tested against the gram-positive and gram-negative bacteria.Conclusion:Otitis media was the most common clinical finding in pa-tients with ear infection.With discharging ear,the gram-negative bacteria were the predominant isolates.The susceptibility pattern of isolates from the study showed that ceftriaxone,ciprofloxacin and gentamicin were the most effective drugs.It is recommended that treatment of ear infections should be based on culture and sensi-tivity at the study sites.Therefore,efforts should be directed towards early diagnosis and treatment of acute ear infection and continued re-evaluation of the resistant patterns of organisms to optimize treatments and reduce complications.

  3. Documentation for the hydrological discharge model

    Energy Technology Data Exchange (ETDEWEB)

    Hagemann, S.; Duemenil, L. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

    1998-10-01

    To improve the representation of hydrological land surface processes, which has so far been treated inadequately in global models of the atmospheric general circulation (GCMs), a model for the lateral waterflows from the continents into the ocean on the global scale was developed. The model describes the translation and retention of the lateral discharge as a function of the spatially distributed land surface characteristics that are globally available. Here, global scale refers to the resolution of 0.5 and lower, corresponding to a typical GCM gridbox area of about 2500 km{sup 2}. This model is called the Hydrological Discharge model or HD model. The HD model computes the discharge only at 0.5 resolution. A model input fields (runoff and drainage, see Sect. 3.1.) from the various GCM resolutions are interpolated to the same 0.5 grid. Thus, input fields may be used from any available resolution, if the corresponding interpolation routine to the 0.5 degree grid is provided. Since the HD model uses a time step of one day, a temporal resolution of one day is sufficient for the input fields. (orig.)

  4. Estimation of peak discharges of historical floods

    Directory of Open Access Journals (Sweden)

    J. Herget

    2014-05-01

    Full Text Available There is no doubt, that the hazard assessment of future floods especially under consideration of the recent environmental change can be significantly improved by the consideration of historic flood events. While flood frequency inventories on local, regional and even European scale are already developed and published, the estimation of their magnitudes indicated by discharges is still challenging. Such data are required due to significant human impact on river channels and floodplains though historic flood levels cannot be related to recent ones or recent discharges. Based on own experiences from single local key studies the general outline of an approach to estimate the discharge of the previous flood based on handed down flood level and topographic data is presented. The model for one-dimensional steady flow is based on the empirical Manning equation for the mean flow velocity. Background and potential sources of information, acceptable simplifications and data transformation for each element of the model-equation are explained and discussed. Preliminary experiences on the accuracy of ±10% are documented and potential approaches for the validation of individual estimations given. A brief discussion on benefits and limitations including a generalized statement on alternative approaches closes the review presentation of the approach.

  5. Electron heating in atmospheric pressure glow discharges

    Science.gov (United States)

    Stark, Robert H.; Schoenbach, Karl H.

    2001-04-01

    The application of nanosecond voltage pulses to weakly ionized atmospheric pressure plasmas allows heating the electrons without considerably increasing the gas temperature, provided that the duration of the pulses is less than the critical time for the development of glow-to-arc transitions. The shift in the electron energy distribution towards higher energies causes a temporary increase in the ionization rate, and consequently a strong rise in electron density. This increase in electron density is reflected in an increased decay time of the plasma after the pulse application. Experiments in atmospheric pressure air glow discharges with gas temperatures of approximately 2000 K have been performed to explore the electron heating effect. Measurements of the temporal development of the voltage across the discharge and the optical emission in the visible after applying a 10 ns high voltage pulse to a weakly ionized steady state plasma demonstrated increasing plasma decay times from tens of nanoseconds to microseconds when the pulsed electric field was raised from 10 to 40 kV/cm. Temporally resolved photographs of the discharge have shown that the plasma column expands during this process. The nonlinear electron heating effect can be used to reduce the power consumption in a repetitively operated air plasma considerably compared to a dc plasma operation. Besides allowing power reduction, pulsed electron heating also has the potential to enhance plasma processes, which require elevated electron energies, such as excimer generation for ultraviolet lamps.

  6. Electric discharge excitation and energy source integration

    Science.gov (United States)

    Grosjean, D. F.

    1985-01-01

    Methods of transferring energy from electrical storage to an electro-negative gas discharge at high repetition rates of approx. modeling of the pertinent kinetics of a He/Xe/HCl gas mixture which was performed in conjunction with various configurations of pulse-forming networks is described; gas thyratrons and magnetic switches were used as switching elements. Due to the relatively constant E/N characterisitics of this system, a stripline arrangement is shown to provide the most efficient method of energy transfer for pulse lengths approx < 50 nsec. Capacitor discharge methods are applicable to shorter pulse lengths. Construction of a closed-cycled, high-rep-rate XeCl gas-discharge laser is described. Operation of an X-ray preionized system at 1.5 kHz is also detailed; no contamination was observed in this configuration. The application of the XeCl laser as a pump source for a high-rep-rate, high-average-power dye laser is also described. A flowing-dye jet was utilized in order to avoid liquid-cell boundary-layer problems of a fast-flow stream. The optical quality of the jet stream was the limiting factor in achieving the power goals. A method of achieving high efficiency in a rare-gas-halide system is proposed via a magnetic switch and prepulse arrangement in conjunctions with a stripline PFN.

  7. Numerical study of a helicon gas discharge

    Science.gov (United States)

    Batishchev, Oleg; Molvig, Kim

    2001-06-01

    Plasma sources based on the helicon gas discharge are widely used in industry [1] due to their high efficiency. We investigate performance of a particular helicon plasma sources designed for the VASIMR [2] plasma thruster. Specifically we are interested in the VX-10 configuration [3] operating with hydrogen or helium plasmas. Firstly, we use our zero-dimensional model to characterize plasma condition and composition [4]. Next we couple it to one-dimensional hybrid model [5] for a rarified gas flow in the system feeding pipe - quartz tube of the helicon. We perform numerical analysis of plasma source operation in different regimes. Results are compared and used to explain experimental data [3]. Finally, we'll discuss more detailed fully kinetic models for the gas and plasma species evolution in the helicon discharge with parameters typical to that of the VASIMR plasma thruster. [1] M.A. Lieberman and A.J.Lihtenberg, , 'Principles of plasma discharges and materials processing', Wiley, NY, 1994; [2] F.Chang-Diaz et al, Bull. APS 45 (7) 129, 2000; [3] J. Squire et al., Bull. APS 45 (7) 130, 2000; [4] O.Batishchev and Kim Molvig, AIAA technical paper 2000-3754, 2000; [5] O.Batishchev and Kim Molvig, AIAA technical paper 2001-0963, 2001.

  8. Nasogastric Tube Placement in Newborns Before Discharge.

    Science.gov (United States)

    Alnemri, Abdulrahman M; Saeed, Anjum; Assiri, Asaad M

    2016-04-01

    The aim of this study was to assess the knowledge of medical staff (physicians) at different levels about insertion or placement of nasogastric tube (NGT) in a normal newborn before discharge. It was a survey-based, observational study conducted at King Khalid University Hospital. Atotal of 103 doctors were sent text message; among those 81 (78.6%) responded. Among the respondents, 27, 16, 11 and 27 were neonatologists, general physicians, obstetricians/ ENT/pediatric surgeons, and senior registrars neonatology (SRN), respectively. Majority of physicians, 57 (70.3%) rejected the idea of insertion of NGTin a normal newborn but in 24 (29.6%), answer was to insert NGTin all the newborns before discharge to check the patency of nasal cavities. Regarding the position, region of doctors and their response, majority from Center said ‘No’(not in favour of insertion) but from South, 17/18 (94.4%) said ‘Yes’(in favour of insertion). Regarding other specialties, majority of them showed rejection of this idea. In conclusion, most of the healthcare professionals, directly involved with neonatal care, rejected the idea of routine insertion of NGTin normal newborn examination before discharge; rather, some non-invasive technique could be opted.

  9. Electrostatic discharges in Saturn's B-ring

    Science.gov (United States)

    Warwick, J. W.; Romig, J. H.; Evans, D. R.

    1983-01-01

    The Voyager observations of electrical discharges in Saturn's rings strongly support earlier speculations on the role played by electrostatics, magnetic fields, and lightning phenomena in the primitive solar system. They also suggest conditions then by direct analogy rather than by extrapolating backwards through time from conditions now. The observed discharges show a pronounced 10h periodicity, which suggests a source in Keplerian orbit at 1.80 + or - 0.01 Saturn radii. In that region, the B ring is thicker than optical depth 1.8 for about 5,000 km. At 1.805 + or - 0.001 Saturn radii, however, the ring is virtually transparent for a gap of width 200 m. It is concluded that a small satellite orbits Saturn at that radius and clears the gap. The gap edges must prevent diffusive filling of the gap by fine material which is especially abundant at this position in the rings and would otherwise destroy the gap in minutes. The discharges represent the satellite's interaction with the outer edge of the gap. Spoke formation may involve the interaction of ring material in the vicinity of the gap.

  10. Study and optimization of the partial discharges in capacitor model ...

    African Journals Online (AJOL)

    model at different temperatures. Etude et ... undegased is measured and the effect of temperature was examined. The partial discharge ... discharges and show that the low temperature ..... Journal Exploring the Frontiers of Physics, Vol. 66 (1),.

  11. 32 CFR 70.9 - Discharge review standards.

    Science.gov (United States)

    2010-07-01

    ... which the applicant was discharged, even though the discharge was determined to have been otherwise...) Awards and decorations; (C) Letters of commendation or reprimand; (D) Combat service; (E) Wounds...

  12. Thermally induced atmospheric pressure gas discharges using pyroelectric crystals

    Science.gov (United States)

    Johnson, Michael J.; Linczer, John; Go, David B.

    2014-12-01

    Using a heated pyroelectric crystal, an atmospheric pressure gas discharge was generated through the input of heat. When put through a change in temperature, the polarization of a pyroelectric can change significantly, creating a substantial electric potential at its surface. When configured with a grounded sharp counter electrode, a large inhomogeneous electric field forms in the interstitial gas to initiate a corona-like discharge. Under constant heating conditions, gaseous ions drifting to the pyroelectric accumulate and screen the electric field, extinguishing the discharge. By thermally cycling the pyroelectric, negative and positive discharges are generated during heating and cooling, respectively, with peak currents on the order of 80 nA. Time-integrated visualization confirmed the generation of both a corona-like discharge and a surface discharge on the pyroelectric. Parametric studies identified that thermal cycling conditions significantly influence discharge formation for this new atmospheric pressure discharge approach.

  13. Treatment Episode Data Set: Discharges (TEDS-D-2009)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Treatment Episode Data Set -- Discharges (TEDS-D) is a national census data system of annual discharges from substance abuse treatment facilities. TEDS-D...

  14. Treatment Episode Data Set: Discharges (TEDS-D-2010)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Treatment Episode Data Set -- Discharges (TEDS-D) is a national census data system of annual discharges from substance abuse treatment facilities. TEDS-D...

  15. Treatment Episode Data Set: Discharges (TEDS-D-2006)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Treatment Episode Data Set -- Discharges (TEDS-D) is a national census data system of annual discharges from substance abuse treatment facilities. TEDS-D...

  16. Treatment Episode Data Set: Discharges (TEDS-D-2007)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Treatment Episode Data Set -- Discharges (TEDS-D) is a national census data system of annual discharges from substance abuse treatment facilities. TEDS-D...

  17. Treatment Episode Data Set: Discharges (TEDS-D-2011)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Treatment Episode Data Set -- Discharges (TEDS-D) is a national census data system of annual discharges from substance abuse treatment facilities. TEDS-D...

  18. Treatment Episode Data Set: Discharges (TEDS-D-2008)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Treatment Episode Data Set -- Discharges (TEDS-D) is a national census data system of annual discharges from substance abuse treatment facilities. TEDS-D...

  19. Visible and VUV images of dielectric barrier discharges in Xe

    Energy Technology Data Exchange (ETDEWEB)

    Mildren, R.P. [Centre for Lasers and Applications, Macquarie University, Sydney, NSW (Australia); Carman, R.J. [Department of Physics, Macquarie University, Sydney, NSW (Australia); Falconer, I.S. [School of Physics A28, University of Sydney, Sydney, NSW (Australia)

    2001-12-07

    We have recorded short exposure images of visible and vacuum ultraviolet (VUV) emission from a Xe dielectric barrier discharge lamp, and investigated the effects of excitation by fast rising pulse and sinusoidal voltage waveforms on the discharge structure. The images from the pulsed discharge are essentially uniform over the active electrode area unlike the sinusoidal discharge which is filamentary. By investigating a single filament discharge, it is also found that a large fraction ((>)90%) of the total visible and VUV emission for sinusoidal excitation is generated from regions outside the filament. The images suggest that the VUV is generated from surface discharges, or 'feelers', which branch out laterally from the filaments. Model calculations suggest that surface or volume discharges, in which the current density is much lower than for filamentary discharges, generate VUV emission more efficiently due to the reduced rate for multi-step electron excitation of Xe* species. (author)

  20. Combustion Enhancement with a Silent Discharge Plasma

    Science.gov (United States)

    Rosocha, Louis

    2003-10-01

    It is well known that the application of an external electric field to a flame can affect its propagation speed, stability, and combustion chemistry (Lawton & Weinberg 1969). External electrodes, arc discharges, and plasma jets have been employed to allow combustible gas mixtures to operate outside their flammability limits by gas heating, injection of free radicals, and field-promoted flame stabilization (Yagodnikov & Voronetskii 1994). Other investigators have carried out experiments with silent electrical discharges applied to propagating flames (Inomata et al 1983, Kim et al 2003). These have demonstrated that the flame propagation velocity is actually decreased (combustion retarded) when a silent discharge is applied directly to the flame region, but that the flame propagation velocity is increased (combustion promoted) when a silent discharge is applied to the unburned gas mixture upstream of a flame. Two other recent works have considered the possibility of combustion enhancement in aircraft gas turbine engine combustor mixers by using a plasma-generating fuel nozzle, that employs an electric-arc or microwave plasma generator, to produce dissociated fuel or ionized fuel (Johnson et al 2001); and pulsed corona-enhanced detonation of fuel-air mixtures in jet engines (Wang et al 2003). In contrast to these prior works, we have employed a silent discharge plasma (SDP) reactor to break up large fuel molecules into smaller molecules and create free radicals or other active species in a gas stream before the fuel is mixed with an oxidizer and combusted. In experiments reported here, a cylindrical SDP reactor was used to 'activate' propane before mixing it with air and igniting the combustible gas mixture. With the plasma, the physical appearance of the flame changes and substantial changes in mass spectrometer fragmentation peaks are observed (e.g., propane fragments decrease and water and carbon dioxide increase). This indicates that the combustion process is

  1. Studying discharges in the Gas Electron Multiplies in Alice Detector

    CERN Document Server

    EُlGedawy, Omar

    2016-01-01

    Characterizing discharges is very important in the operation of the GEM detector. Once the discharges happen, a current will go through the GEM, the voltages across the GEM foils sides drop, charge amplification cannot take place anymore, resulting in a loss of signal. So the goal is to understand how the discharges evolve and propagate, in order to find requirements on the voltage settings, which allow to decrease the discharge probability.

  2. 34 CFR 674.61 - Discharge for death or disability.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false Discharge for death or disability. 674.61 Section 674... Discharge for death or disability. (a) Death. An institution must discharge the unpaid balance of a borrower... disability as defined in § 674.51(aa)(1)—(1) General. A borrower's Defense, NDSL, or Perkins loan is...

  3. Optical Spectra of the High Voltage Erosive Water Discharge

    CERN Document Server

    Pirozerski, A L

    2008-01-01

    In the present paper kinetics of emission spectra of the high voltage erosive water discharge at near ultraviolet and visible spectral ranges has been investigated. Obtained results show a similarity of physical properties of this discharge (and of corresponding plasmoids) to that of some other types of erosional discharges which also result in the formation of dust-gas fireballs.

  4. Research on Discharging Mechanism of Powder Mixed EDM

    Institute of Scientific and Technical Information of China (English)

    WANG Yuangang; ZHAO Fuling

    2006-01-01

    This paper presents investigations on discharging mechanism in powder mixed EDM. By analyzing the inception, growth of electrical tree and the ignition of discharges in liquid filled gap, the whole discharging process is proposed. It is explored that the reason of modification of ignition behaves by adding fine particle powders of metal or semiconductor to the working liquid.

  5. 46 CFR 14.305 - Entries in continuous discharge book.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Entries in continuous discharge book. 14.305 Section 14.305 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MERCHANT MARINE OFFICERS AND SEAMEN SHIPMENT... discharge book. If the merchant mariner holds a continuous discharge book, the master or individual...

  6. The Discharge Coefficient of a Centre-Pivot Roof Window

    DEFF Research Database (Denmark)

    Iqbal, Ahsan; Afshari, Alireza; Nielsen, Peter V.

    2012-01-01

    value of discharge coefficient is used. The constant value of discharge coefficient leads to deceptive airflow estimation in the cases of centre-pivot roof windows. The object of this paper is to study and evaluate the discharge coefficient of the centre pivot roof window. Focus is given...

  7. 32 CFR 724.221 - Scheduling of discharge reviews.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false Scheduling of discharge reviews. 724.221 Section 724.221 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL NAVAL DISCHARGE REVIEW BOARD Authority/Policy for Departmental Discharge Review § 724.221 Scheduling of...

  8. Recent results from studies of electric discharges in the mesosphere

    DEFF Research Database (Denmark)

    Neubert, Torsten; Rycroft, M.; Farges, T.

    2008-01-01

    The paper reviews recent advances in studies of electric discharges in the stratosphere and mesosphere above thunderstorms, and their effects on the atmosphere. The primary focus is on the sprite discharge occurring in the mesosphere, which is the most commonly observed high altitude discharge by...

  9. Enhanced volume production of negative ions in the post discharge of a multicusp hydrogen discharge

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, M.B.; Bacal, M.; Graham, W.G. (Laboratoire de Physique des Milieux Ionises, Laboratoire du C.N.R.S., Ecole Polytechnique, 91128 Palaiseau Cedex (France))

    1991-08-15

    In this paper we demonstrate a new concept in the production of negative hydrogen ions in a low-pressure multicusp discharge. The discharge voltage is modulated to produce a non-Maxwellian, hot-electron plasma during the current pulse, followed by a cool Maxwellian electron plasma in the post discharge. This procedure, of separating in time the required hot and cold electron plasmas required for volume H{sup {minus}} production, is called a temporal filter. The time evolution of the electron energy distribution function is measured using the time-resolved second derivative of a Langmuir probe characteristic. Time-resolved measurements of the negative ion density are made using laser photodetachment. The measurements show that the negative ion density in the center of the source, at a gas pressure of 0.07 Pa, increases by a factor of 2 when the discharge is switched off. At this low pressure the average H{sup {minus}} beam current extracted from the source, when operated with a discharge current of 1 A in the pulse modulated mode exceeds the H{sup {minus}} beam current from a 5 A continuously operated source. The increase in efficiency of the pulsed source is explained in terms of a two-step H{sup {minus}} production mechanism.

  10. Modified PADSS (Post Anaesthetic Discharge Scoring System) for monitoring outpatients discharge.

    Science.gov (United States)

    Palumbo, Piergaspare; Tellan, Guglielmo; Perotti, Bruno; Pacilè, Maria Antonietta; Vietri, Francesco; Illuminati, Giulio

    2013-01-01

    The decision to discharge a patient undergoing day surgery is a major step in the hospitalization pathway, because it must be achieved without compromising the quality of care, thus ensuring the same assistance and wellbeing as for a long-term stay. Therefore, the use of an objective assessment for the management of a fair and safe discharge is essential. The authors propose the Post Anaesthetic Discharge Scoring System (PADSS), which considers six criteria: vital signs, ambulation, nausea/vomiting, pain, bleeding and voiding. Each criterion is given a score ranging from 0 to 2. Only patients who achieve a score of 9 or more are considered ready for discharge. Furthermore, PADSS has been modified to ensure a higher level of safety, thus the "vital signs" criteria must never score lower than 2, and none of the other five criteria must ever be equal to 0, even if the total score reaches 9. The effectiveness of PADSS was analyzed on 2432 patients, by recording the incidence of postoperative complications and the readmission to hospital. So far PADDS has proved to be an efficient system that guarantees safe discharge.

  11. Lightning discharges and discharges from overhead power lines with human burn injuries as consequences

    Directory of Open Access Journals (Sweden)

    Javor Sanja

    2013-01-01

    Full Text Available Discharges from overhead power lines and lightning discharges may severely endanger human life and health. If non-lethal, burn injuries may also last for a lifetime, so as Lichtenberg figures caused by lightning discharges. Some accidents with burns are discussed in this paper and recommendations given for safety reasons. Specific energy transferred by typical lightning strokes currents given in the standard IEC 62305 is calculated. The aim of the paper is to suggest a simple expression for the estimation of safe approach distances to overhead lines, especially if high temperatures and changes in terrain reduced the secure height above ground, or if carrying elevated objects. Results of these calculations are compared to safe approach distances given in regulations of different countries. Safe distances from railway power lines are also considered.

  12. Optimal length of capacitive-discharge and glow-discharge excilamps

    Science.gov (United States)

    Boichenko, A. M.; Erofeev, M. V.; Sosnin, E. A.; Tarasenko, V. F.; Yakovlenko, S. I.

    2007-06-01

    The optimal tube length of capacitive-discharge and glow-discharge excimer lamps with ring and circular electrodes of equal radii is considered. It is demonstrated that, at the same potential difference between electrodes and their radii, the ratio of the optimal lengths of the tubes with circular and ring electrodes depends on width L of the ring electrodes. The ratio of the lengths decreases with decreasing L. A relationship between the tube length and radius, the width of ring electrodes, and the minimum voltage at the tube that provide for an approximately uniform glow of the discharge column in the presence of voltage pulses with opposite polarities at the electrodes is derived.

  13. State waste discharge permit application: Hydrotest, maintenance and construction discharges. Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-01

    On December 23, 1991, the US DOE< Richland Operation Office (RL) and the Washington State Department of Ecology (Ecology) agreed to adhere to the provisions of the Department of Ecology Consent Order No. DE91NM-177 (216 Consent Order) (Ecology and US DOE 1991). The 216 Consent Order list regulatory milestones for liquid effluent streams at the Hanford Site and requires compliance with the permitting requirements of Washington Administrative Code. Hanford Site liquid effluent streams discharging to the soil column have been categorized on the 216 Consent Order as follows: Phase I Streams; Phase II Streams; Miscellaneous Streams. Phase I and Phase II Streams were initially addressed in two report. Miscellaneous Streams are subject to the requirements of several milestones identified in the 216 Consent Order. This document constitutes the Categorical State Waste Discharge Permit application for hydrotest,maintenance and construction discharges throughout the Hanford Site. This categorical permit application form was prepared and approved by Ecology.

  14. A Study on the improvement of Paldang dam discharge evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Song, Young Chul; Kim, Chong Hak; Lee, Dae Soo [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center; Lee, Won Hwan; Cho, Won Chul; Heo, Jun Haeng [Yonsei Univ., Seoul (Korea, Republic of)

    1995-12-31

    Besides the original purpose of electric power generation, the Paldang dam plays such important roles as flood control and water supply in the Han river. However, significant drawdown of the downstream water level since 1973 has caused considerable differences between the real discharges and the estimated values currently in use. This study was performed to improve discharge evaluation method and to provide new discharge table appropriate for the changed condition. Through the physical model tests assisted by numerical test, the discharge equations were modified, the discharge table was revised for steady and unsteady flow conditions, but the gate operation rules proved reasonable and remained unchanged. (author). 81 refs., 166 figs.

  15. From Aldrete to PADSS: Reviewing discharge criteria after ambulatory surgery.

    Science.gov (United States)

    Ead, Heather

    2006-08-01

    Nurses working in perianesthesia care areas use discharge scoring criteria to complete patient assessments and ensure patient readiness for discharge or transfer to the next phase of recovery. However, all discharge criteria have both advantages and disadvantages. Comparative studies on the reliability of the different discharge criteria in use are extremely limited. As the acuity of our aging population increases, as well as the number of annual surgeries performed on an outpatient basis, it is most timely to ensure that we are following evidence-based discharge criteria.

  16. Discharge planning as part of daily nursing practice.

    Science.gov (United States)

    Foust, Janice B

    2007-05-01

    Nurses deal with planning posthospitalization care within increasingly urgent focused environments and amid competing priorities. The purpose of this qualitative study was to examine nurses' discharge planning efforts as these occurred in practice. Eight nurses were observed and interviewed as they cared for selected patients. Major findings indicate that nurses' expectations of patients' progress guided their discharge assessments, teaching, and planning over time. Discharge teaching was a prominent part of daily practice that became more specific as hospital discharge neared. A gap between observed and documented discharge planning efforts existed, which poses significant challenges for nurses in many positions.

  17. Self-similarity of skeletal structures in laboratory high current electric discharges (plasmas and fractal dust deposits), severe weather phenomena and space

    Science.gov (United States)

    Kukushkin, A. B.; Rantsev-Kartinov, V. A.

    2003-10-01

    The phenomenon of skeletal structures (tubules, cartwheels, and their simple combinations) formerly found in laboratory plasmas, is extended to atmospheric and cosmic phenomena (Phys. Lett. A 306, 175, Dec. 2002). The long-lived filaments in plasmas have been suggested (1998) to possess a skeleton self-assembled during electric breakdown from wildly produced nanodust. The proof-of-concept studies revealed the skeletal structures in (1) plasmas in tokamaks, Z-pinches, plasma focus (in the range 0.01-10 cm), including the electric breakdown stage of discharge, (2) dust deposits in tokamak (10 nm - 10 microns), (3) hailstones (1-10 cm), tornado (10 m -1 km), (4) a wide class of objects in space (10^11-10^23 cm). The similarity of, and the trend toward self-similarity in, skeletal structures suggest all them to possess a fractal condensed matter of particular topology of the fractal. Here we discuss probable role of skeletal structures in the fast nonlocal transport of energy in strongly localized severe weather phenomena (tornado) and laboratory plasmas.

  18. DEPOSITION CARBON NANOSTRUCTURES BY SURFATRON GENERATED DISCHARGE

    Directory of Open Access Journals (Sweden)

    Marina Davydova

    2014-12-01

    Full Text Available Carbon nanostructures were deposited by surface wave discharge using various Ar/CH4/ CO2 gas mixture ratios. The morphology was controlled by adjusting of gas concentration and was investigated by scanning electron microscopy (SEM. Also, the influence of the low temperature plasma treatment and process time on the wettability of the diamond films has been studied. The results indicate that for hydrogen termination of diamond surface indicate that the temperature as low as 400°C and treatment time of 15 min is sufficient to attain the p-type surface conductivity of diamond.

  19. Building micro and nanosystems with electrochemical discharges

    Energy Technology Data Exchange (ETDEWEB)

    Wuethrich, Rolf, E-mail: wuthrich@encs.concordia.c [Department of Mechanical and Industrial Engineering, Concordia University, 1455 de Maisonneuve Blvd. West, Montreal, QC (Canada); Allagui, Anis [Department of Mechanical and Industrial Engineering, Concordia University, 1455 de Maisonneuve Blvd. West, Montreal, QC (Canada)

    2010-11-30

    Since the discovery of the electrochemical discharge phenomenon by Fizeau and Foucault, several contributions have expanded the wide range of applications associated with this high current density electrochemical process. The complexity of the phenomenon, from the macroscopic to the microscopic scales, led since then to experimental and theoretical studies from different research fields. This contribution reviews the chemical and electrochemical perspectives where a mechanistic model based on results from radiation chemistry of aqueous solutions is proposed. In addition applications to micro-machining and fabrication of nanoparticles are discussed.

  20. Hydrogen Production from Methanol Using Corona Discharges

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Hydrogen production at room temperature from liquid methanol has been conductedusing corona discharge. The content of water in methanol solution has a significant effect on thisproduction. When water concentration increases from 1.0 % to 16.7 %, the methanol conversionrate changes from 0.196 to 0.284 mol/h. An important finding in this investigation is theformation of ethylene glycol as a major by-product. The yield of ethylene glycol is ranged from0.0045 to 0.0075 mol/h based on the water content.

  1. A numerical study of planar discharge motion

    Directory of Open Access Journals (Sweden)

    Benkhaldoun F.

    2014-06-01

    Full Text Available Presented paper describes a numerical study of discharge plasma motion. This non-stationary phenomenon with steep gradients and sharp peaks in unknowns is described as a coupled problem of convection-diffusion equation with source term for electron, ion densities and Poisson’s equation for electric potential. The numerical method is 2nd order of accuracy in space and time and it uses dynamical adaptation of unstructured triangular mesh. Results of numerical studies included size of computational domain, type of boundary conditions and numerical convergence test are presented.

  2. Desensitizing nano powders to electrostatic discharge ignition

    Energy Technology Data Exchange (ETDEWEB)

    Steelman, Ryan [Texas Tech Univ., Lubbock, TX (United States). Dept. of Mechanical Engineering; Clark, Billy [Texas Tech Univ., Lubbock, TX (United States). Dept. of Mechanical Engineering; Pantoya, Michelle L. [Texas Tech Univ., Lubbock, TX (United States). Dept. of Mechanical Engineering; Heaps, Ronald J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Daniels, Michael A. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-08-01

    Electrostatic discharge (ESD) is a main cause for ignition in powder media ranging from grain silos to fireworks. Nanoscale particles are orders of magnitude more ESD ignition sensitive than their micron scale counterparts. This study shows that at least 13 vol. % carbon nanotubes (CNT) added to nano-aluminum and nano-copper oxide particles (nAl + CuO) eliminates ESD ignition sensitivity. The CNT act as a conduit for electric energy and directs electric charge through the powder to desensitize the reactive mixture to ignition. For nanoparticles, the required CNT concentration for desensitizing ESD ignition acts as a diluent to quench energy propagation.

  3. Analysis of radiofrequency discharges in plasma

    Science.gov (United States)

    Kumar, Devendra; McGlynn, Sean P.

    1992-01-01

    Separation of laser optogalvanic signals in plasma into two components: (1) an ionization rate change component, and (2) a photoacoustic mediated component. This separation of components may be performed even when the two components overlap in time, by measuring time-resolved laser optogalvanic signals in an rf discharge plasma as the rf frequency is varied near the electrical resonance peak of the plasma and associated driving/detecting circuits. A novel spectrometer may be constructed to make these measurements. Such a spectrometer would be useful in better understanding and controlling such processes as plasma etching and plasma deposition.

  4. A PDE-based partial discharge simulator

    Science.gov (United States)

    Villa, Andrea; Barbieri, Luca; Gondola, Marco; Leon-Garzon, Andres R.; Malgesini, Roberto

    2017-09-01

    Partial discharges are the main ageing and failure mechanism of solid insulating materials subjected to alternated current stresses. This phenomenon, from a simulation point of view, has been almost always tackled using semi-empirical schemes. In this work, a fully physically-based model, based on a set of conservation partial differential equations, is introduced. A numerical algorithm, specifically designed to solve this particular problem, is developed and its validation is discussed considering some experimental data acquired in a simple geometry containing an isolated void.

  5. Ultrasonic Vibration Electrical Discharge Machining in Gas

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new method of ultrasonic vibration electrical discharge machining(UEDM) in gas is proposed in this paper. In UEDM in gas, the gap between tool electrode and workpiece is small(about 0.01mm), and the voltage between them is higher than EDM in liquid, so short circuit is easy to take place. It is very important for improving the MRR to avoid short circuit. Therefore, some measures have been taken, a rotation and a planetary motion are superimposed upon the tool electrode. During UEDM in gas, workpiece is vi...

  6. SOCIAL ADAPTATION OF DISCHARGED MILITARY PERSONNEL

    Directory of Open Access Journals (Sweden)

    Tatyana A. Stakhy

    2014-01-01

    Full Text Available In the life plans of servicemen, retired includevocational training or retraining, developmentof new relations, the formation of a new value system based on the new realities and theirsocial experience.The article considers legal and organizationalsupport of former soldiers, analyzed groupof servicemen discharged from the Armed Forces, as a specific social group and identified its place in the structure of Russiansociety; revealed the ways and forms ofadaptation to new conditions of life; to makean analysis of the life plans of servicemen,removed to the reserve.

  7. Early Stage of Pulsed Discharge in Water

    Institute of Scientific and Technical Information of China (English)

    卢新培; 潘垣; 刘克富; 刘明海; 张寒虹

    2001-01-01

    The bubble radius at the early stage of discharge in water is investigated using high-speed photography. Some simulation results on the bubble radius are presented, which are in agreement with the experimental results, with a maximum difference of about 10%. The reasons why the peak pressure of the first shock wave is only related to the energy released in the bubble during the first half period are addressed. The energy released in the bubble after the first half period increases the bubble pulsation period, but it produces no more than 10% under the peak pressure of the second shock wave.

  8. Point discharge current measurements beneath dust devils

    Science.gov (United States)

    Lorenz, Ralph D.; Neakrase, Lynn D. V.; Anderson, John P.; Harrison, R. Giles; Nicoll, Keri A.

    2016-12-01

    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 current ramping up towards closest approach, switching to a decaying negative current as the devil recedes. The currents, induced on a small wire about 10 cm above the ground, correlate with dust devil intensity (pressure drop) and dust loading, and reached several hundred picoAmps.

  9. Stage-discharge rating curves based on satellite altimetry and modeled discharge in the Amazon basin

    Science.gov (United States)

    Paris, Adrien; Dias de Paiva, Rodrigo; Santos da Silva, Joecila; Medeiros Moreira, Daniel; Calmant, Stephane; Garambois, Pierre-André; Collischonn, Walter; Bonnet, Marie-Paule; Seyler, Frederique

    2016-05-01

    In this study, rating curves (RCs) were determined by applying satellite altimetry to a poorly gauged basin. This study demonstrates the synergistic application of remote sensing and watershed modeling to capture the dynamics and quantity of flow in the Amazon River Basin, respectively. Three major advancements for estimating basin-scale patterns in river discharge are described. The first advancement is the preservation of the hydrological meanings of the parameters expressed by Manning's equation to obtain a data set containing the elevations of the river beds throughout the basin. The second advancement is the provision of parameter uncertainties and, therefore, the uncertainties in the rated discharge. The third advancement concerns estimating the discharge while considering backwater effects. We analyzed the Amazon Basin using nearly one thousand series that were obtained from ENVISAT and Jason-2 altimetry for more than 100 tributaries. Discharge values and related uncertainties were obtained from the rain-discharge MGB-IPH model. We used a global optimization algorithm based on the Monte Carlo Markov Chain and Bayesian framework to determine the rating curves. The data were randomly allocated into 80% calibration and 20% validation subsets. A comparison with the validation samples produced a Nash-Sutcliffe efficiency (Ens) of 0.68. When the MGB discharge uncertainties were less than 5%, the Ens value increased to 0.81 (mean). A comparison with the in situ discharge resulted in an Ens value of 0.71 for the validation samples (and 0.77 for calibration). The Ens values at the mouths of the rivers that experienced backwater effects significantly improved when the mean monthly slope was included in the RC. Our RCs were not mission-dependent, and the Ens value was preserved when applying ENVISAT rating curves to Jason-2 altimetry at crossovers. The cease-to-flow parameter of our RCs provided a good proxy for determining river bed elevation. This proxy was validated

  10. OH radicals generated by DC corona discharge for improving the pulsed discharge desulfuration efficiency

    Institute of Scientific and Technical Information of China (English)

    LI Jie; LI Guo-feng; WU Yan; WANG Ning-hui; HUANG Qiu-nan

    2004-01-01

    Positive DC corona discharge is formed with needle-plate electrode configuration, in which the water vapor is ejected though the needle points. The purpose is to increase the numbers of the water-based radicals, ionize the water molecule and improve the desulfuration efficiency of pulsed corona reactor. The water ions were determined by four stages molecular beam mass spectrometer and diagnose the water-based radicals by emission spectrograph. A conclusion on formation of ions and radicals with DC corona discharges can be drawn.

  11. Discharge characteristics of motor units during long-duration contractions.

    Science.gov (United States)

    Pascoe, Michael A; Holmes, Matthew R; Stuart, Douglas G; Enoka, Roger M

    2014-10-01

    The purpose of the study was to determine how long humans could sustain the discharge of single motor units during a voluntary contraction. The discharge of motor units in first dorsal interosseus of subjects (27.8 ± 8.1 years old) was recorded for as long as possible. The task was terminated when the isolated motor unit stopped discharging action potentials, despite the ability of the individual to sustain the abduction force. Twenty-three single motor units were recorded. Task duration was 21.4 ± 17.8 min. When analysed across discharge duration, mean discharge rate (10.6 ± 1.8 pulses s(-1)) and mean abduction force (5.5 ± 2.8% maximum) did not change significantly (discharge rate, P = 0.119; and abduction force, P = 0.235). In contrast, the coefficient of variation for interspike interval during the initial 30 s of the task was 22.2 ± 6.0% and increased to 31.9 ± 7.0% during the final 30 s (P < 0.001). All motor units were recruited again after 60 s of rest. Although subjects were able to sustain a relatively constant discharge rate, the cessation of discharge was preceded by a gradual increase in discharge variability. The findings also showed that the maximal duration of human motor unit discharge exceeds that previously reported for the discharge elicited in motor neurons by intracellular current injection in vitro.

  12. Pulsed positive streamer discharges in air at high temperatures

    Science.gov (United States)

    Ono, Ryo; Kamakura, Taku

    2016-08-01

    Atmospheric-pressure air pulsed positive streamer discharges are generated in a 13 mm point-plane gap in the temperature range of 293 K-1136 K, and the effect of temperature on the streamer discharges is studied. When the temperature is increased, the product of applied voltage and temperature VT proportional to the reduced electric field can be used as a primary parameter that determines some discharge parameters regardless of temperature. For a given VT, the transferred charge per pulse, streamer diameter, product of discharge energy and temperature, and length of secondary streamer are almost constant regardless of T, whereas the streamer velocity decreases with increasing T and the decay rate of the discharge current is proportional to 1/T. The N2(C) emission intensity is approximately determined by the discharge energy independent of T. These results are useful to predict the streamer discharge and its reactive species production when the ambient temperature is increased.

  13. Study of the Discharge Mode in Micro-Hollow Cathode

    Institute of Scientific and Technical Information of China (English)

    HE Feng; HE Shoujie; ZHAO Xiaofei; GUO Bingang; OUYANG Jiting

    2012-01-01

    In this study, micro-hollow cathode discharge (MHCD) is investigated by a fluid model with drift-diffusion approximation. The MHC device is a cathode/dielectric/anode sandwich structure with one hole of a diameter D=200 um. The gas is a Ne/Xe mixture at a pressure p=50-500 Torr. The evolutions of the discharge show that there are two different discharge modes. At larger pD the discharge plasma and high density excited species expand along the cathode surface and, a ringed discharge mode is formed. At smaller pD, the discharge plasma and the excited species expand along the axis of the cathode aperture to form a columnar discharge.

  14. Characterizing uniform discharge in atmospheric helium by numerical modelling

    Institute of Scientific and Technical Information of China (English)

    Lü Bo; Wang Xin-Xin; Luo Hai-Yun; Liang Zhuo

    2009-01-01

    One-dimensional fluid model of dielectric barrier discharge (DBD) in helium at atmospheric pressure was estab-lished and the discharge was numerically simulated. It was found that not only the spatial distributions of the internal parameters such as the electric field, the electron density and ion density are similar to those in a low-pressure glow discharge, but also the visually apparent attribute (light emission) is exactly the same as the observable feature of a low-pressure glow discharge. This confirms that the uniform DBD in atmosphcric helium is a glow type discharge. The fact that the thickness of the cathode fall layer is about 0.5 ram, much longer than that of a normal glow dischargc in helium at atmospheric pressure, indicates the discharge being a sub-normal glow discharge close to normal one. The multipulse phenomenon was reproduced in the simulation and a much less complicated explanation for this phenomenon was given.

  15. Quantitative relationship between the maximum streamer length and discharge voltage of a pulsed positive streamer discharge in water

    Science.gov (United States)

    Wen, Xiaoqiong; Li, Qian; Li, Jingsen; Ren, Chunsheng

    2017-08-01

    A linear relationship has been realized between the maximum streamer length and discharge voltage of a pulsed positive streamer discharge by measuring the streamer length in water with conductivity of 100 μS cm-1 using high-speed photography. Based on Ohm’s law, a quantitative equation has been derived for the dependence of the maximum streamer length on the discharge voltage of a pulsed positive streamer discharge in water. According to the equation, our results suggest that the streamers spontaneously stop propagating through water due to the voltage at the streamer head dropping below the ignition voltage of a pulsed positive streamer discharge.

  16. Electrostatic Discharge Properties of Fused Silica Coatings

    Science.gov (United States)

    Andersen, Allen; Sim, Charles; Dennison, J. R.

    2012-10-01

    The electric field value at which electrostatic discharge (ESD) occurs was studied for thin coatings of fused silica (highly disordered SiO2/SiOx) on conductive substrates, such as those encountered as optical coatings and in Si microfabrication. The electrostatic breakdown field was determined using an increasing voltage, while monitoring the leakage current. A simple parallel-plate capacitor geometry was used, under medium vacuum and at temperatures down to ˜150 K using a liquid N2 reservoir. The breakdown field, pre-breakdown arcing and I-V curves for fused silica samples are compared for ˜60 nm and ˜80 μm thick, room and low temperature, and untreated and irradiated samples. Unlike typical I-V results for polymeric insulators, the thin film silica samples did not exhibit pre-breakdown arcing, displayed transitional resistivity after initial breakdown, and in many cases showed evidence of a second discontinuity in the I-V curves. This diversity of observed discharge phenomena is discussed in terms of breakdown modes and defect generation on a microscopic scale.

  17. First gaseous boronization during pulsed discharge cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Ko, J., E-mail: jinseok@nfri.re.kr [Department of Physics, University of Wisconsin, Madison, WI (United States); Den Hartog, D.J.; Goetz, J.A.; Weix, P.J.; Limbach, S.T. [Department of Physics, University of Wisconsin, Madison, WI (United States)

    2013-01-15

    The first successful gaseous boronization during a pulsed discharge is reported. Sublimation of o-carborane (C{sub 2}B{sub 10}H{sub 12}) combined with pulsed discharge plasmas with a repetition rate of 1 Hz is used to produce a hard boron-containing coating for reversed field pinch (RFP) plasmas in the Madison Symmetric Torus. X-ray photoelectron spectroscopy with Ar ion beam etching for silicon coupons installed at the plasma boundary shows about 60% boron concentration in the deposited layer. Both profilometer and scanning electron microscope analyses of the silicon coupons imply a strong toroidally non-uniform deposition depending on the location of the o-carborane injection. The layer thickness ranges from 50 to 300 nm. Ellipsometry calibrated with the profilometer results yields a refractive index of 2.2-2.3 for the films. The high refractive index implies that the coating is hard and has a well-ordered morphology. A reduction in wall recycling has consistently been observed after all boronization sessions. Comparison of the X-ray spectra in standard RFP plasmas before and after boronization indicates a slight decrease in the effective ionic charge.

  18. First gaseous boronization during pulsed discharge cleaning

    Science.gov (United States)

    Ko, J.; Den Hartog, D. J.; Goetz, J. A.; Weix, P. J.; Limbach, S. T.

    2013-01-01

    The first successful gaseous boronization during a pulsed discharge is reported. Sublimation of o-carborane (C2B10H12) combined with pulsed discharge plasmas with a repetition rate of 1 Hz is used to produce a hard boron-containing coating for reversed field pinch (RFP) plasmas in the Madison Symmetric Torus. X-ray photoelectron spectroscopy with Ar ion beam etching for silicon coupons installed at the plasma boundary shows about 60% boron concentration in the deposited layer. Both profilometer and scanning electron microscope analyses of the silicon coupons imply a strong toroidally non-uniform deposition depending on the location of the o-carborane injection. The layer thickness ranges from 50 to 300 nm. Ellipsometry calibrated with the profilometer results yields a refractive index of 2.2-2.3 for the films. The high refractive index implies that the coating is hard and has a well-ordered morphology. A reduction in wall recycling has consistently been observed after all boronization sessions. Comparison of the X-ray spectra in standard RFP plasmas before and after boronization indicates a slight decrease in the effective ionic charge.

  19. Closed cycle electric discharge laser design investigation

    Science.gov (United States)

    Baily, P. K.; Smith, R. C.

    1978-01-01

    Closed cycle CO2 and CO electric discharge lasers were studied. An analytical investigation assessed scale-up parameters and design features for CO2, closed cycle, continuous wave, unstable resonator, electric discharge lasing systems operating in space and airborne environments. A space based CO system was also examined. The program objectives were the conceptual designs of six CO2 systems and one CO system. Three airborne CO2 designs, with one, five, and ten megawatt outputs, were produced. These designs were based upon five minute run times. Three space based CO2 designs, with the same output levels, were also produced, but based upon one year run times. In addition, a conceptual design for a one megawatt space based CO laser system was also produced. These designs include the flow loop, compressor, and heat exchanger, as well as the laser cavity itself. The designs resulted in a laser loop weight for the space based five megawatt system that is within the space shuttle capacity. For the one megawatt systems, the estimated weight of the entire system including laser loop, solar power generator, and heat radiator is less than the shuttle capacity.

  20. Early discharge. Risks, benefits, and who decides.

    Science.gov (United States)

    Kiely, M; Drum, M A; Kessel, W

    1998-09-01

    Over the last several decades, there has been a significant decrease in the length of hospital stays for mothers and their newborns, ranging from the average of 7 to 10 days before World War II to approximately 2 days in recent years. Many women saw the benefit of early discharge as a means to demedicalize the birth process, to be home with their families sooner, and to have their deliveries be a more positive experience. Although the trend toward shorter hospital stays was originally initiated by consumer interest, the recent further shortening of maternity stays has escalated as a result of insurance and managed care plans attempting to contain health care costs. With this trend toward earlier discharge, a litany of problems have been reported, including missed newborn screening, jaundice, feeding problems, missed congenital anomalies, and readmissions. Although cost-efficient use of health care is vital, the ultimate goal should not only be the prevention of unnecessary morbidity and mortality, but the promotion of health and well being for the child and family.

  1. Electrostatic discharge testing of electroexplosive devices

    Energy Technology Data Exchange (ETDEWEB)

    Hingorani, S.L.

    1990-01-01

    Electrostatic discharge (ESD) testing of electroexplosive devices has previously been regarded as single pulse, go/no-go testing, the emphasis being on the safety of the devices when exposed to human handling. For some components it has been found to be a destructive test; for others the test is performed 100% in production product-acceptance testing and is considered a nondestructive and nondegrading test if the component does not fire. Recent studies performed by R. J. Fisher at Sandia have resulted in a new model of the worst case human body electrostatic discharge that is more accurate than the model that is currently in use for testing electroexplosive components. In addition, recent requirements for no degradation or loss of reliability after multiple exposures (up to 100) have changed the go/no-go nature of the test. Several components have been tested to the new ESD model; results regarding both safety and reliability will be presented and discussed. 9 refs., 7 figs., 2 tabs.

  2. Pulsed microhollow cathode discharge excimer sources

    Science.gov (United States)

    Moselhy, Mohamed; Shi, Wenhui; Strak, Robert H.; Schoenbach, Karl H.

    2001-10-01

    Microhollow cathode discharges (MHCDs) are non-equilibrium, high-pressure gas discharges between perforated electrodes separated by a dielectric layer. Typical dimensions for the electrode foil thickness and hole diameter are 100 μm. Direct current experiments in xenon, argon, neon, helium, argon fluoride, and xenon chloride [1,2] have been performed. The excimer efficiency varies between 1 % and 9 %. Pulsed operation allowed us to increase the current from 8 mA (dc) to approximately 80 mA (pulsed with a pulse width of 700 μs), limited by the onset of instabilities. The total excimer power was found to increase linearly with current, however, the radiant emittance and efficiency stayed constant. Reducing the pulse duration into the nanosecond range allowed us to increase the current into the ampere range. The maximum measured excimer power was 2.75 W per microdischarge. The maximum radiant emittance was 15 W/cm^2 and the efficiency reached values of 20 %. This effect is assumed to be due to non-equilibrium electron heating in the high-pressure plasma [3]. This work was supported by the National Science Foundation under grant # CTS0078618. 1. Karl H. Schoenbach, Ahmed El-Habachi, Mohamed M. Moselhy, Wenhui Shi, and Robert H. Stark, Physics of Plasmas 7, 2186 (2000). 2. P. Kurunczi, J. Lopez, H. Shah, and K. Becker, Int. J. Mass Spectrom. 205, 277 (2001). 3. Robert H. Stark and Karl H. Schoenbach, J. Appl. Phys. 89, 3568 (2001).

  3. Ozone kinetics in low-pressure discharges

    Science.gov (United States)

    Guerra, Vasco; Marinov, Daniil; Guaitella, Olivier; Rousseau, Antoine

    2012-10-01

    Ozone kinetics is quite well established at atmospheric pressure, due to the importance of ozone in atmospheric chemistry and to the development of industrial ozone reactors. However, as the pressure is decreased and the dominant three-body reactions lose importance, the main mechanisms involved in the creation and destruction of ozone are still surrounded by important uncertainties. In this work we develop a self-consistent model for a pulsed discharge and its afterglow operating in a Pyrex reactor with inner radius 1 cm, at pressures in the range 1-5 Torr and discharge currents of 40-120 mA. The model couples the electron Boltzmann equation with a system of equations for the time evolution of the heavy particles. The calculations are compared with time-dependent measurements of ozone and atomic oxygen. Parametric studies are performed in order to clarify the role of vibrationally excited ozone in the overall kinetics and to establish the conditions where ozone production on the surface may become important. It is shown that vibrationally excited ozone does play a significant role, by increasing the time constants of ozone formation. Moreover, an upper limit for the ozone formation at the wall in these conditions is set at 10(-4).

  4. Advances in the Remote Glow Discharge Experiment

    Science.gov (United States)

    Dominguez, Arturo; Zwicker, A.; Rusaits, L.; McNulty, M.; Sosa, Carl

    2014-10-01

    The Remote Glow Discharge Experiment (RGDX) is a DC discharge plasma with variable pressure, end-plate voltage and externally applied axial magnetic field. While the experiment is located at PPPL, a webcam displays the live video online. The parameters (voltage, magnetic field and pressure) can be controlled remotely in real-time by opening a URL which shows the streaming video, as well as a set of Labview controls. The RGDX is designed as an outreach tool that uses the attractive nature of a plasma in order to reach a wide audience and extend the presence of plasma physics and fusion around the world. In March 2014, the RGDX was made publically available and, as of early July, it has had approximately 3500 unique visits from 107 countries and almost all 50 US states. We present recent upgrades, including the ability to remotely control the distance between the electrodes. These changes give users the capability of measuring Paschen's Law remotely and provides a comprehensive introduction to plasma physics to those that do not have access to the necessary equipment.

  5. Effect of air flow on the micro-discharge dynamics in an array of integrated coaxial microhollow dielectric barrier discharges

    Science.gov (United States)

    Nayak, Gaurav; Du, Yanjun; Brandenburg, Ronny; Bruggeman, Peter J.

    2017-03-01

    The micro-discharge properties and evolution in a 2D array of integrated coaxial microhollow dielectric barrier discharges are studied by using highly time-resolved electrical and optical diagnostics. The study is focused on the effect of the gas flow rate and gas residence time on discharge properties. The investigated integrated coaxial microhollow discharge geometry allows operating the discharge at exceptionally small residence times, which can be equal to or even smaller than the discharge period, at reasonable gas flow rates. The gas flow has an impact on gas heating, residual humidity, pre-ionization density and the densities of excited and reactive species produced by previous discharges. A unique voltage–charge plot is obtained with elongated periods without discharge activity. A very significant effect of flow on NO emission is observed that relates to the impact of flow on the NO production in these micro-discharges. Using the emission intensities of molecular bands of the second positive system of nitrogen and the first negative system of the nitrogen ion, effective reduced electric field strengths are obtained with a maximum equal to 870 Td. The reduced electric field decreases with increasing gas flow rate. This behavior is consistent with the reduction of the overall discharge intensity due to a reduced amount of charges present in the discharge gap. Both the flow rate and a reduction in water impurity changing the ion mobility can be responsible for the different effective electric field distributions at the highest and no flow conditions.

  6. Medication reconciliation to solve discrepancies in discharge documents after discharge from the hospital.

    NARCIS (Netherlands)

    Geurts, M.M.; Flier, M. van der; Vries-Bots, A.M. de; Brink van der Wal, T.I.; Gier, J.J. de

    2013-01-01

    BACKGROUND: When patients are admitted to, and discharged from hospital there is a high chance of discrepancies and errors occurring during the transfer of patients' medication information. This often causes drug related problems. Correct and fast communication of patients' medication information

  7. Medication reconciliation to solve discrepancies in discharge documents after discharge from the hospital

    NARCIS (Netherlands)

    Geurts, Marlies M. E.; van der Flier, Merel; de Vries-Bots, Anne M. B.; Brink-van der Wal, Thaliet I. C.; de Gier, Johan J.

    Background When patients are admitted to, and discharged from hospital there is a high chance of discrepancies and errors occurring during the transfer of patients' medication information. This often causes drug related problems. Correct and fast communication of patients' medication information

  8. Optical characteristics for capacitively and inductively radio frequency discharge and post-discharge of helium

    Energy Technology Data Exchange (ETDEWEB)

    Tanışlı, Murat, E-mail: mtanisli@anadolu.edu.tr; Şahin, Neslihan [Department of Physics, Anadolu University, Yunusemre Campus 26470 Eskişehir (Turkey)

    2016-01-15

    The optical properties for radiofrequency (RF) post-discharge of pure helium (He) with two different methods as capacitively and inductively have been presented using the modified Boltzmann method in comparison. Optical emission spectroscopy (OES) is often used in the diagnosis of laboratory plasma, such as gas discharge plasma. OES is a very useful method for calculating of the electron temperature in the plasma and the determination of different atoms and molecules. In this study, OES is applied for characterizations of capacitively and inductively RF He plasma at pressures between 0.62 and 2.2 mbar for newly reactor type. Plasmas are generated with an RF power generator at a frequency of 13.56 MHz and output powers of 100, 160, and 200 W. Spectra have been evaluated in the range 200–1200 nm by an optical spectrometer. At low pressure, the main spectral features reported are the wavelengths of the atomic He transitions at 388.87 and 728.13 nm. The atomic emission intensities showed a maximum in inductive system when the pressure is about 0.62 mbar. OES of capacitive discharge and inductive discharge is compared in detail. The transition for 587.56 nm is shown to be increased in time.

  9. Charging of moving surfaces by corona discharges sustained in air

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jun-Chieh, E-mail: junchwan@umich.edu; Kushner, Mark J., E-mail: mjkush@umich.edu [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109-2122 (United States); Zhang, Daihua, E-mail: dhzhang@tju.edu.cn [Tianjin University, Tianjin (China); Leoni, Napoleon, E-mail: napoleon.j.leoni@hp.com; Birecki, Henryk, E-mail: henryk.birecki@hp.com; Gila, Omer, E-mail: omer-gila@hp.com [Hewlett-Packard Research Labs, Palo Alto, California 94304 (United States)

    2014-07-28

    Atmospheric pressure corona discharges are used in electrophotographic (EP) printing technologies for charging imaging surfaces such as photoconductors. A typical corona discharge consists of a wire (or wire array) biased with a few hundred volts of dc plus a few kV of ac voltage. An electric discharge is produced around the corona wire from which electrons drift towards and charge the underlying dielectric surface. The surface charging reduces the voltage drop across the gap between the corona wire and the dielectric surface, which then terminates the discharge, as in a dielectric barrier discharge. In printing applications, this underlying surface is continuously moving throughout the charging process. For example, previously charged surfaces, which had reduced the local electric field and terminated the local discharge, are translated out of the field of view and are replaced with uncharged surface. The uncharged surface produces a rebound in the electric field in the vicinity of the corona wire which in turn results in re-ignition of the discharge. The discharge, so reignited, is then asymmetric. We found that in the idealized corona charging system we investigated, a negatively dc biased corona blade with a dielectric covered ground electrode, the discharge is initially sustained by electron impact ionization from the bulk plasma and then dominated by ionization from sheath accelerated secondary electrons. Depending on the speed of the underlying surface, the periodic re-ignition of the discharge can produce an oscillatory charging pattern on the moving surface.

  10. Charging of moving surfaces by corona discharges sustained in air

    Science.gov (United States)

    Wang, Jun-Chieh; Zhang, Daihua; Leoni, Napoleon; Birecki, Henryk; Gila, Omer; Kushner, Mark J.

    2014-07-01

    Atmospheric pressure corona discharges are used in electrophotographic (EP) printing technologies for charging imaging surfaces such as photoconductors. A typical corona discharge consists of a wire (or wire array) biased with a few hundred volts of dc plus a few kV of ac voltage. An electric discharge is produced around the corona wire from which electrons drift towards and charge the underlying dielectric surface. The surface charging reduces the voltage drop across the gap between the corona wire and the dielectric surface, which then terminates the discharge, as in a dielectric barrier discharge. In printing applications, this underlying surface is continuously moving throughout the charging process. For example, previously charged surfaces, which had reduced the local electric field and terminated the local discharge, are translated out of the field of view and are replaced with uncharged surface. The uncharged surface produces a rebound in the electric field in the vicinity of the corona wire which in turn results in re-ignition of the discharge. The discharge, so reignited, is then asymmetric. We found that in the idealized corona charging system we investigated, a negatively dc biased corona blade with a dielectric covered ground electrode, the discharge is initially sustained by electron impact ionization from the bulk plasma and then dominated by ionization from sheath accelerated secondary electrons. Depending on the speed of the underlying surface, the periodic re-ignition of the discharge can produce an oscillatory charging pattern on the moving surface.

  11. Electrostatic Discharge Effects on Thin Film Resistors

    Science.gov (United States)

    Sampson, Michael J.; Hull, Scott M.

    1999-01-01

    Recently, open circuit failures of individual elements in thin film resistor networks have been attributed to electrostatic discharge (ESD) effects. This paper will discuss the investigation that came to this conclusion and subsequent experimentation intended to characterize design factors that affect the sensitivity of resistor elements to ESD. The ESD testing was performed using the standard human body model simulation. Some of the design elements to be evaluated were: trace width, trace length (and thus width to length ratio), specific resistivity of the trace (ohms per square) and resistance value. However, once the experiments were in progress, it was realized that the ESD sensitivity of most of the complex patterns under evaluation was determined by other design and process factors such as trace shape and termination pad spacing. This paper includes pictorial examples of representative ESD failure sites, and provides some options for designing thin film resistors that are ESD resistant. The risks of ESD damage are assessed and handling precautions suggested.

  12. Characteristics of pellet injected discharges in TEXTOR

    Energy Technology Data Exchange (ETDEWEB)

    Finken, K.H. [Institut fuer Plasmaphysik, Forschungszentrum Juelich GmbH, Assocition Euratom-KFA, 52425 Juelich (Germany); Sato, K.N. [National Institute for Fusion Science, Nagoya 464-01 (Japan); Akiyama, H. [Kumamoto University, Kumamoto 860 (Japan); Fuchs, G.; Jaspers, R. [Institut fuer Plasmaphysik, Forschungszentrum Juelich GmbH, Assocition Euratom-KFA, 52425 Juelich (Germany); Kogoshi, S. [Science University of Tokyo, Noda 278 (Japan); Koslowski, H.R.; Mank, G. [Institut fuer Plasmaphysik, Forschungszentrum Juelich GmbH, Assocition Euratom-KFA, 52425 Juelich (Germany); Sakakita, H.; Sakamoto, M. [National Institute for Fusion Science, Nagoya 464-01 (Japan); Sander, M.; Soltwisch, H. [Institut fuer Plasmaphysik, Forschungszentrum Juelich GmbH, Assocition Euratom-KFA, 52425 Juelich (Germany)

    1995-09-01

    Pellets injected into the TEXTOR tokamak lead to a density profile peaking which is strongest at low plasma current and weakest at high current independent of {ital B}{sub {ital T}}. After the injection two types of density oscillations are excited, the first type follows immediately the injection and the second one is excited with a delay of more than ten milliseconds. The oscillations are also observed in runaway discharges; the synchrotron light from the relativistic electrons drops after the pellet injection and is subsequently modulated due to a trapping of the runaways in magnetic islands. First Faraday measurements have been performed indicating that the distribution of the plasma current is not measurably modified by the pellet. {copyright} {ital 1995 American Institute of Physics.}

  13. FLOW REGIMES BELOW AERATORS FOR DISCHARGE TUNNELS

    Institute of Scientific and Technical Information of China (English)

    MA Fei; WU Jian-hua

    2012-01-01

    The flow regimes below an aerator influence directly the air entrainment and the cavitation damage control.Based on the theoretical considerations,the experiments of the aerator for a discharge tunnel were conducted,and the relationships between the flow regime and hydraulic and geometric parameters were investigated.The results showed that,there are two kinds of threshold values for the flow regime conversions.One is Fr1-2 standing for the conversion from the fully filled cavity to the partially filled cavity,and the other is Fr2-3 which shows the change from the partially filled cavity to the net air cavity.Two empirical expressions were obtained for the conversions of the flow regimes,which can be used in the designs of the aerators.

  14. River Network Modeling Beyond Discharge at Gauges

    Science.gov (United States)

    David, C. H.; Famiglietti, J. S.; Salas, F. R.; Whiteaker, T. L.; Maidment, D. R.; Tolle, K.

    2014-12-01

    Over the past two decades, the estimation of water flow in river networks within hydro-meteorological models has mostly focused on simulations of natural processes and on their verification at available river gauges. Despite valuable existing skills in hydrologic modeling the accounting for anthropogenic actions in current models remains limited. The emerging availability of datasets containing measured dam outflows and reported irrigation withdrawals motivates their inclusion into simulations of flow in river networks. However, the development of advanced river network models accounting for such datasets of anthropogenic influences requires a detailed data model and a thorough handling of the various data types, sources and time scales. This contribution details the development of a consistent data model suitable for accounting some observations of anthropogenic modifications of the surface water cycle and presents the impact of such inclusion on simulations using the Routing Application for Parallel computatIon of Discharge (RAPID).

  15. Behaviour of air discharged from a sparger

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Yoon Yeong [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2000-03-01

    This research has been performed as a part of the project, Development of Design Verification Technology for Korea Next Generation Reactor. At first, current state of the art of the bubble dynamics and the result will be used to develop an optimum tool including computer code for analysis of air or air-steam mixture bubble, which is discharged from a sparger. Introduced are linear perturbation; spherical bubble cloud theory; bubble interaction; and Volume of Fluid, a method of tracking free surface, which is to be used in computational fluid dynamics. An analysis was performed for the oscillation of an air bubble of perfect spherical shape. The heat transfer through the bubble surface is considered, although the effect was not so significant. The effect of initial and boundary conditions were investigated and the correlation equation was developed. 42 refs., 22 figs., 2 tabs. (Author)

  16. Electrostatic Discharge testing of propellants and primers

    Energy Technology Data Exchange (ETDEWEB)

    Berry, R.B.

    1994-02-01

    This report presents the results of testing of selected propellants and primers to Electrostatic Discharge (ESD) characteristic of the human body. It describes the tests and the fixturing built to accommodate loose material (propellants) and the packed energetic material of the primer. The results indicate that all powders passed and some primers, especially the electric primers, failed to pass established requirements which delineate insensitive energetic components. This report details the testing of components and materials to four ESD environments (Standard ESD, Severe ESD, Modified Standard ESD, and Modified Severe ESD). The purpose of this study was to collect data based on the customer requirements as defined in the Sandia Environmental Safety & Health (ES&H) Manual, Chapter 9, and to define static sensitive and insensitive propellants and primers.

  17. Sheet Plasma Produced by Hollow Cathode Discharge

    Institute of Scientific and Technical Information of China (English)

    张龙; 张厚先; 杨宣宗; 冯春华; 乔宾; 王龙

    2003-01-01

    A sheet plasma is produced by a hollow cathode discharge under an axial magnetic field.The plasma is about 40cm in length,4 cm in width and 1cm in thickness.The electron density is about 108cm-3.The hollow cathode is made to be shallow with a large opening,which is different from the ordinary deep hollow cathode.A Langmuir probe is used to detect the plasma.The electron density and the spatial distribution of the plasma change when voltage,pressure and the magnetic field vary.A peak and a data fluctuation at about 200 G-300 G are observed in the variation of electron density(or thickness of the sheet plasma)with the magnetic field.Our work will be helpful in characterizing the sheet plasma and will make the production of dense sheet plasma more controllable.

  18. Investigation of gas discharge impulse image intensifiers

    Energy Technology Data Exchange (ETDEWEB)

    Gushchin, E.M. E-mail: evgeni@phep.mephi.msk.su; Somov, S.V.; Timofeev, M.K

    1999-08-21

    The gas discharge impulse image intensifiers (GDIII) operated in the streamer mode are studied in this work. The GDIII has a resolution of 5-15 lines/cm and light amplification up to {approx}10{sup 10}. The possibility to design a single-electron GDIII for RICH-detectors is considered. For this purpose the emission of photoelectrons in He, Ne, Ar, Xe, CO{sub 2}, iC{sub 4}H{sub 10} and their mixtures in the 50-760 Torr pressure range have been investigated. The best working gas for the GDIII is Ne+({approx}0.1%)iC{sub 4}H{sub 10} mixture having an electron output factor up to 0.45.

  19. Partial Discharge Degradation of Several Biodegradable Polymers

    Science.gov (United States)

    Fuse, Norikazu; Fujita, Shinjiro; Hirai, Naoshi; Tanaka, Toshikatsu; Kozako, Masahiro; Kohtoh, Masanori; Okabe, Shigemitsu; Ohki, Yoshimichi

    Partial discharge (PD) resistance was examined by applying a constant voltage for four kinds of biodegradable polymers, i.e. poly-L-lactic acid (PLLA), polyethylene terephthalate succinate (PETS), poly ε-caprolactone butylene succinate (PCL-BS), and polybutylene succinate (PBS), and the results were compared with those of low density polyethylene (LDPE) and crosslinked low density polyethylene (XLPE). The PD resistance is determined by the erosion depth and the surface roughness caused by PDs, and is ranked as LDPE ≅ XLPE > PLLA ≅ PETS > PBS > PCL-BS. This means that the sample with a lower permittivity has better PD resistance. Furthermore, observations of the sample surface by a polarization microscope and a laser confocal one reveal that crystalline regions with spherulites are more resistant to PDs than amorphous regions. Therefore, good PD resistance can be achieved by the sample with a high crystallinity and a low permittivity.

  20. Thermal discharges from the Savannah River Plant

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.J.; Jacobsen, W.R.; Rabon, E.W.; Tilly, L.J.

    1972-09-01

    The nuclear production reactors at the AEC's Savannah River Plant, located by siting requirements, utilize on-site natural watercourses, swamps, and cooling water impoundments to dissipate heat in effluent cooling water. Stream-swamp cooling is the most efficient and economical cooling mechanism available to the two reactors presently using this method of heat dissipation. The effects on the Savannah River of high temperature water discharged from the reactors are thus minimized, and detrimental environmental consequences are confined to the plantsite. A large cooling water impoundment, which is currently being used to dissipate heat from one reactor, has furnished an extensive area for biological research into the effects on the aquatic community resulting from its varied thermal conditions.