WorldWideScience

Sample records for sustained glow discharges

  1. Mechanism behind self-sustained oscillations in direct current glow discharges and in dusty plasmas

    CERN Document Server

    Cho, Sung Nae

    2013-01-01

    An alternative explanation to the mechanism behind self-sustained oscillations of ions in direct current (DC) glow discharges is provided. Such description is distinguished from the one provided by fluid models, where oscillations are attributed to positive feedback mechanism associated with photoionization of particles and photoemission of electrons from the cathode. Here, oscillations arise as consequence of interaction between an ion and surface charges induced by it at the bounding electrodes. Such mechanism provides an elegant explanation to why self-sustained oscillations occur only in the negative resistance region of the voltage-current characteristic curve in DC glow discharges. It is found that oscillation frequencies increase with ion's surface charge density, but at the rate which is significantly slower than it does with electric field. The presented mechanism also describes the self-sustained oscillations of ions in dusty plasmas, demonstrating that oscillations in dusty plasmas and DC glow disc...

  2. Constricted glow discharge plasma source

    Science.gov (United States)

    Anders, Andre; Anders, Simone; Dickinson, Michael; Rubin, Michael; Newman, Nathan

    2000-01-01

    A constricted glow discharge chamber and method are disclosed. The polarity and geometry of the constricted glow discharge plasma source is set so that the contamination and energy of the ions discharged from the source are minimized. The several sources can be mounted in parallel and in series to provide a sustained ultra low source of ions in a plasma with contamination below practical detection limits. The source is suitable for applying films of nitrides such as gallium nitride and oxides such as tungsten oxide and for enriching other substances in material surfaces such as oxygen and water vapor, which are difficult process as plasma in any known devices and methods. The source can also be used to assist the deposition of films such as metal films by providing low-energy ions such as argon ions.

  3. Powerful glow discharge excilamp

    Science.gov (United States)

    Tarasenko, Victor F.; Panchenko, Aleksey N.; Skakun, Victor S.; Sosnin, Edward A.; Wang, Francis T.; Myers, Booth R.; Adamson, Martyn G.

    2002-01-01

    A powerful glow discharge lamp comprising two coaxial tubes, the outer tube being optically transparent, with a cathode and anode placed at opposite ends of the tubes, the space between the tubes being filled with working gas. The electrodes are made as cylindrical tumblers placed in line to one other in such a way that one end of the cathode is inserted into the inner tube, one end of the anode coaxially covers the end of the outer tube, the inner tube penetrating and extending through the anode. The increased electrodes' surface area increases glow discharge electron current and, correspondingly, average radiation power of discharge plasma. The inner tube contains at least one cooling liquid tube placed along the axis of the inner tube along the entire lamp length to provide cathode cooling. The anode has a circumferential heat extracting radiator which removes heat from the anode. The invention is related to lighting engineering and can be applied for realization of photostimulated processes under the action of powerful radiation in required spectral range.

  4. Radiation power control of the industrial CO2 lasers excited by a nonself-sustained glow discharge with regard to dissociation in a working gas mixture

    Science.gov (United States)

    Shemyakin, Andrey N.; Rachkov, Michael Yu.; Solovyov, Nikolay G.; Yakimov, Mikhail Yu.

    2018-01-01

    The action of a working gas mixture degradation related to the plasma chemical reactions in a glow discharge on the laser output power of the molecular laser excited by a nonself-sustained glow discharge has been studied by the example of an industrial laser of ;Lantan; CO2 laser series. It was found that the laser power overshoot when operating on a fresh gas mixture may exceed 3 times power level set in a steady-state regime. The working algorithm for the control system was proposed and developed setting standard fresh CO2/N2/He laser gas mixture to plasma chemical equilibrium composition during the laser turn-on procedure after full refill of a working gas mixture.

  5. Non-self-sustained glow discharge with electrostatic confinement of electrons sustained by a fast neutral molecule beam

    Science.gov (United States)

    Metel, A. S.; Melnik, Yu. A.; Panin, V. V.

    2011-04-01

    Experimental study of plasma produced at the nitrogen pressure 0.2-1 Pa in the chamber volume V ≈ 0.12 m3 as a result of injection into the chamber of a broad nitrogen molecule beam with 1-4 keV energy and 0.1-1 A equivalent current is carried out, and the study results are presented. Dependences of the plasma density distribution on the beam equivalent current I b , energy E b , and gas pressure p indicate a crucial role of fast molecules in gas ionization, and the probe characteristics reveal two groups of plasma electrons with the temperatures T e ˜ 0.4 eV and T e ˜ 16 eV. Immersion in plasma of an electrode isolated from the chamber and application to the electrode of a positive voltage U result in non-self-sustained discharge. When U changes from ˜0.5 to ˜1.5 V, the discharge current I rapidly rises to a certain value I*, and after that the rate of rise dI/ dU drops by an order of magnitude. At U ˜ 10 V, the current I rises to I 0 ≈ 1.5 I*, and dI/ dU once again drops by an order of magnitude. Current I 0 specifies the number of electrons produced inside the chamber per second, and it grows up with E b , I b , and p. At U > 20 V, due to gas ionization by fast electrons emitted by the chamber and accelerated up to the energy ˜ eU in the sheath between the plasma and the chamber walls, the current I rises again. When U grows up to ˜50 V, production of fast electrons with energies exceeding the ionization threshold begins inside the sheath, and the ionization intensity rises dramatically. At U > 150 V, contribution of fast electrons to gas ionization already exceeds the contribution of fast molecules, and the plasma density and its distribution homogeneity inside the chamber both grow up substantially. However, even in this case, the discharge is non-self-sustained, and only at U > 300 V it does not expire when the beam source is switched off.

  6. Glow plasma jet - experimental study of a transferred atmospheric pressure glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Guerra-Mutis, Marlon H [Mares Oil Ltd., Instituto Colombiano del Petroleo (ICP) - ECOPETROL (Colombia); U, Carlos V Pelaez [Laboratorio de Control Magnetico de Fluidos, Instituto Colombiano del Petroleo (ICP) - ECOPETROL (Colombia); H, Rafael Cabanzo [Laboratorio de Espectroscopia Atomico-Molecular (LEAM) - UIS (Colombia)

    2003-05-01

    In this paper we present the experimental study of a glow plasma jet (GPJ) obtained from a transferred atmospheric pressure glow discharge (APGD) operating at 60 Hz. The characterization of the emission spectra for both electrical discharges is presented and the electrical circuit features for APGD generation are discussed. The potentiality of GPJ as a source of active species for depletion of contaminants in liquid hydrocarbon fractions is also established.

  7. Multifunctional Glow Discharge Analyzer for Spacecraft Monitoring Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and Penn State University (PSU) propose to develop a highly sensitive spectrometer based on glow discharge emission for the...

  8. Simulation of nonstationary phenomena in atmospheric-pressure glow discharge

    Science.gov (United States)

    Korolev, Yu. D.; Frants, O. B.; Nekhoroshev, V. O.; Suslov, A. I.; Kas'yanov, V. S.; Shemyakin, I. A.; Bolotov, A. V.

    2016-06-01

    Nonstationary processes in atmospheric-pressure glow discharge manifest themselves in spontaneous transitions from the normal glow discharge into a spark. In the experiments, both so-called completed transitions in which a highly conductive constricted channel arises and incomplete transitions accompanied by the formation of a diffuse channel are observed. A model of the positive column of a discharge in air is elaborated that allows one to interpret specific features of the discharge both in the stationary stage and during its transition into a spark and makes it possible to calculate the characteristic oscillatory current waveforms for completed transitions into a spark and aperiodic ones for incomplete transitions. The calculated parameters of the positive column in the glow discharge mode agree well with experiment. Data on the densities of the most abundant species generated in the discharge (such as atomic oxygen, metastable nitrogen molecules, ozone, nitrogen oxides, and negative oxygen ions) are presented.

  9. Oxidation of 1020 steel in the abnormal glow discharge

    Science.gov (United States)

    García Zúñiga, J. A.; Sarmiento Santos, A.; Gómez, E. Y. Soto

    2017-01-01

    1020 steel is a material very used for surface treatment in the abnormal glow discharge. Because the composition of the gaseous atmosphere has an important influence on the results of plasma treatment, in this work the oxidation process of 1020 steel is verified on the abnormal glow discharge under different concentrations of air (20% to 100%) at temperatures of 600°C and 900°C. For each atmosphere used mass variation is measured during the process of surface oxidation, the structure and microstructure of the oxide film formed is observed and also its mechanical properties through its microhardness.

  10. [Automatic adjustment control system for DC glow discharge plasma source].

    Science.gov (United States)

    Wan, Zhen-zhen; Wang, Yong-qing; Li, Xiao-jia; Wang, Hai-zhou; Shi, Ning

    2011-03-01

    There are three important parameters in the DC glow discharge process, the discharge current, discharge voltage and argon pressure in discharge source. These parameters influence each other during glow discharge process. This paper presents an automatic control system for DC glow discharge plasma source. This system collects and controls discharge voltage automatically by adjusting discharge source pressure while the discharge current is constant in the glow discharge process. The design concept, circuit principle and control program of this automatic control system are described. The accuracy is improved by this automatic control system with the method of reducing the complex operations and manual control errors. This system enhances the control accuracy of glow discharge voltage, and reduces the time to reach discharge voltage stability. The glow discharge voltage stability test results with automatic control system are provided as well, the accuracy with automatic control system is better than 1% FS which is improved from 4% FS by manual control. Time to reach discharge voltage stability has been shortened to within 30 s by automatic control from more than 90 s by manual control. Standard samples like middle-low alloy steel and tin bronze have been tested by this automatic control system. The concentration analysis precision has been significantly improved. The RSDs of all the test result are better than 3.5%. In middle-low alloy steel standard sample, the RSD range of concentration test result of Ti, Co and Mn elements is reduced from 3.0%-4.3% by manual control to 1.7%-2.4% by automatic control, and that for S and Mo is also reduced from 5.2%-5.9% to 3.3%-3.5%. In tin bronze standard sample, the RSD range of Sn, Zn and Al elements is reduced from 2.6%-4.4% to 1.0%-2.4%, and that for Si, Ni and Fe is reduced from 6.6%-13.9% to 2.6%-3.5%. The test data is also shown in this paper.

  11. Experimental study of voltage fluctuations in a glow discharge

    Science.gov (United States)

    Yunusov, R. F.; Garipov, M. M.

    2017-11-01

    The article is devoted to the experimental study of voltage pulsations in a glow discharge. The longitudinal discharge was ignited in a stream of air moving in a cylindrical discharge chamber (DC). Copper hollow electrodes were located at a distance of a = (2-8) cm from each other along the axis of the DC. The gas pressure P = (4.7 - 26) kPa and its flow rate G = (0-0.06) g/s were monitored. The discharge current and voltage varied accordingly in the ranges: I = (20-100) mA, U = (1, 5 - 4, 2) kV. The current-voltage characteristics of the discharge were measured. The voltage decreased with increasing current, which is typical for a given type of discharge. The oscillations of the discharge voltage were registered by an oscilloscope; the current-voltage characteristic of the discharge was recorded by a two-coordinate recorder. Three regions of the current-voltage characteristic were detected. The luminous positive discharge column (PC) occupied the entire interelectrode space in the current region I = (100-70) mA. In the current range I = (70-40) mA there is a smooth transition to the discharge without visible glow of the PC with a significant increase in the discharge voltage. With further reduction of the current intensity (the third region), the discharge exists almost at a constant voltage until its quenching. Low-frequency and high-frequency oscillations of the discharge voltage were observed at the boundary of the second and third regions of the current-voltage characteristic.

  12. Dust particle charge distribution in a stratified glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Sukhinin, Gennady I [Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Lavrentyev Ave., 1, Novosibirsk 630090 (Russian Federation); Fedoseev, Alexander V [Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Lavrentyev Ave., 1, Novosibirsk 630090 (Russian Federation); Ramazanov, Tlekkabul S [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty 050012 (Kazakhstan); Dzhumagulova, Karlygash N [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty 050012 (Kazakhstan); Amangaliyeva, Rauan Zh [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty 050012 (Kazakhstan)

    2007-12-21

    The influence of a highly pronounced non-equilibrium characteristic of the electron energy distribution function in a stratified dc glow discharge on the process of dust particle charging in a complex plasma is taken into account for the first time. The calculated particle charge spatial distribution is essentially non-homogeneous and it can explain the vortex motion of particles at the periphery of a dusty cloud obtained in experiments.

  13. Glow discharge sources for atomic and molecular analyses

    Science.gov (United States)

    Storey, Andrew Patrick

    Two types of glow discharges were used and characterized for chemical analysis. The flowing atmospheric pressure afterglow (FAPA) source, based on a helium glow discharge (GD), was utilized to analyze samples with molecular mass spectrometry. A second GD, operated at reduced pressure in argon, was employed to map the elemental composition of a solid surface with novel optical detection systems, enabling new applications and perspectives for GD emission spectrometry. Like many plasma-based ambient desorption-ionization sources being used around the world, the FAPA requires a supply of helium to operate effectively. With increased pressures on global helium supply and pricing, the use of an interrupted stream of helium for analysis was explored for vapor and solid samples. In addition to the mass spectra generated by the FAPA source, schlieren imaging and infrared thermography were employed to map the behavior of the source and its surroundings under the altered conditions. Additionally, a new annular microplasma variation of the FAPA source was developed and characterized. A spectroscopic imaging system that utilized an adjustable-tilt interference filter was used to map the elemental composition of a sample surface by glow discharge emission spectroscopy. This apparatus was compared to other GD imaging techniques for mapping elemental surface composition. The wide bandpass filter resulted in significant spectral interferences that could be partially overcome with chemometric data processing. Because time-resolved GD emission spectroscopy can provide fine depth-profiling measurements, a natural extension of GD imaging would be its application to three-dimensional characterization of samples. However, the simultaneous cathodic sputtering that occur across the sample results in a sampling process that is not completely predictable. These issues are frequently encountered when laterally varied samples are explored with glow discharge imaging techniques. These insights

  14. The Use of DC Glow Discharges as Undergraduate Educational Tools

    Energy Technology Data Exchange (ETDEWEB)

    Stephanie A. Wissel and Andrew Zwicker, Jerry Ross, and Sophia Gershman

    2012-10-09

    Plasmas have a beguiling way of getting students excited and interested in physics. We argue that plasmas can and should be incorporated into the undergraduate curriculum as both demonstrations and advanced investigations of electromagnetism and quantum effects. Our device, based on a direct current (DC) glow discharge tube, allows for a number of experiments into topics such as electrical breakdown, spectroscopy, magnetism, and electron temperature.

  15. Exploration to generate atmospheric pressure glow discharge plasma in air

    Science.gov (United States)

    Wenzheng, LIU; Chuanlong, MA; Shuai, ZHAO; Xiaozhong, CHEN; Tahan, WANG; Luxiang, ZHAO; Zhiyi, LI; Jiangqi, NIU; Liying, ZHU; Maolin, CHAI

    2018-03-01

    Atmospheric pressure glow discharge (APGD) plasma in air has high application value. In this paper, the methods of generating APGD plasma in air are discussed, and the characteristics of dielectric barrier discharge (DBD) in non-uniform electric field are studied. It makes sure that APGD in air is formed by DBD in alternating current electric field with using the absorbing electron capacity of electret materials to provide initial electrons and to end the discharge progress. Through designing electric field to form two-dimensional space varying electric field and three-dimensional space varying electric field, the development of electron avalanches in air-gap is suppressed effectively and a large space of APGD plasma in air is generated. Further, through combining electrode structures, a large area of APGD plasma in air is generated. On the other hand, by using the method of increasing the density of initial electrons, millimeter-gap glow discharge in atmospheric pressure air is formed, and a maximum gap distance between electrodes is 8 mm. By using the APGD plasma surface treatment device composed of contact electrodes, the surface modification of high polymer materials such as aramid fiber and polyester are studied and good effect of modifications is obtained. The present paper provides references for the researchers of industrial applications of plasma.

  16. Uncertainty of relative sensitivity factors in glow discharge mass spectrometry

    Science.gov (United States)

    Meija, Juris; Methven, Brad; Sturgeon, Ralph E.

    2017-10-01

    The concept of the relative sensitivity factors required for the correction of the measured ion beam ratios in pin-cell glow discharge mass spectrometry is examined in detail. We propose a data-driven model for predicting the relative response factors, which relies on a non-linear least squares adjustment and analyte/matrix interchangeability phenomena. The model provides a self-consistent set of response factors for any analyte/matrix combination of any element that appears as either an analyte or matrix in at least one known response factor.

  17. Sputtering of the 1020 AISI steel in abnormal glow discharge

    Science.gov (United States)

    García Zúñiga, J. A.; Sarmiento Santos, A.; Álvarez Luna, B.

    2017-12-01

    In all material treated in Sbnormal Glow Discharge (AGD) the phenomenon of sputtering occurs. In this work we study the sputtering suffered at different temperatures by AISI 1020 steel subjected to a DC discharge in two types of atmospheres. The steel samples were previously sanded until obtaining mirror brightness and subjected to the AGD plasma in the gaseous atmospheres of H2 and Ar. The temperature for each sputtering process was set in the range of 420°C to 600°C. In these samples the mass variation was measured and the yield sputtering processes was determined. Next, the simulation of the sputtering process was performed in the SRIM/TRIM 2008 software, by adjusting sputtering yield computational computations to those experimentally measured, in order to determine the energy with which the responsible ions of the sputtering collide with studied target.

  18. Determination of the plasma impedance of a glow discharge in carbon dioxide

    Science.gov (United States)

    Kiselev, A. S.; Smirnov, E. A.

    2017-07-01

    In this work an expression for the dynamic resistance of a glow discharge flowing in long tubes is obtained and analyzed. The expression describes the physical processes occurring in the positive column of a glow discharge. The frequency dependences of the active and reactive components as well as the dynamic resistance module for the discharge conditions corresponding to CO2-lasers have been calculated. Based on the simulation results developed a computer program in the C# programming language for modeling the dynamic resistance discharge of glow discharge lasers.

  19. Auxiliary glow discharge in the trigger unit of a hollow-cathode thyratron

    Energy Technology Data Exchange (ETDEWEB)

    Korolev, Yu. D.; Landl, N. V., E-mail: landl@lnp.hcei.tsc.ru; Geyman, V. G.; Frants, O. B.; Shemyakin, I. A.; Nekhoroshev, V. O. [Russian Academy of Sciences, Institute of High-Current Electronics, Siberian Branch (Russian Federation)

    2016-08-15

    Results from studies of a low-current glow discharge with a hollow cathode are presented. A specific feature of the discharge conditions was that a highly emissive tablet containing cesium carbonate was placed in the cathode cavity. In the absence of a tablet, the discharge ignition voltage was typically ≥3.5 kV, while the burning voltage was in the range of 500–600 V. The use of the tablet made it possible to decrease the ignition voltage to 280 V and maintain the discharge burning voltage at a level of about 130 V. A model of the current sustainment in a hollow-cathode discharge is proposed. Instead of the conventional secondary emission yield, the model uses a generalized emission yield that takes into account not only ion bombardment of the cathode, but also the emission current from an external source. The model is used to interpret the observed current−voltage characteristics. The results of calculations agree well with the experimental data. It is shown that, in some discharge modes, the external emission current from the cathode can reach 25% of the total discharge current.

  20. Surface analysis of titanium biological modification with glow discharge.

    Science.gov (United States)

    Chang, Yu-Chi; Feng, Sheng-Wei; Huang, Haw-Ming; Teng, Nai-Chia; Lin, Che-Tong; Lin, Hsi-Kuei; Wang, Peter-D; Chang, Wei-Jen

    2015-06-01

    Glow discharge plasma (GDP) technology has been used to graft various proteins to the titanium surface, including albumin, type I collagen, but without fibronectin. The aim of this study was to evaluate and analyze the physical properties of fibronectin-grafted titanium surfaces after GDP treatment. Grade II titanium discs after cleaning and autoclaving were considered as original specimens, thus divided into four groups. The groups were different upon two treatments (GDP only and fibronectin grafting after GDP) and two storage temperature (4°C and 25°C). The implant surface morphology was characterized by scanning electron microscopy (SEM), roughness measurement, and wettability evaluation. The concentration relationship of fibronectin was by fluorescein isothiocyanate (FITC) labeling. SEM images showed that regular planar texture revealed on the surface of GDP-treated group, and irregular-folding protein was found on the fibronectin-grafted discs. Fibronectin-grafted groups had higher hydrophilicity and greater surface roughness than GDP-treated specimens. The storage temperature did not make obvious difference on the surface topography, wettability, and roughness. The number of fibronectin dots on the titanium surface labeling by FITC had positive relationship with the concentration of fibronectin solution used. Biologically modified titanium surface is more hydrophilic and rougher than GDP-treated ones. GDP treatment combined with fibronectin grafting increased the surface hydrophilicity and surface roughness of titanium discs, which may attribute to the affinity of cell adhesion, migration, proliferation, and differentiation. © 2013 Wiley Periodicals, Inc.

  1. Radio frequency glow discharge-induced acidification of fluoropolymers.

    Science.gov (United States)

    Krawczyk, Benjamin M; Baltrusaitis, Jonas; Yoder, Colin M; Vargo, Terrence G; Bowden, Ned B; Kader, Khalid N

    2011-12-01

    Fluoropolymer surfaces are unique in view of the fact that they are quite inert, have low surface energies, and possess high thermal stabilities. Attempts to modify fluoropolymer surfaces have met with difficulties in that it is difficult to control the modification to maintain bulk characteristics of the polymer. In a previously described method, the replacement of a small fraction of surface fluorine by acid groups through radio frequency glow discharge created a surface with unexpected reactivity allowing for attachment of proteins in their active states. The present study demonstrates that 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC) reacts with the acid groups on fluoropolymer surfaces in a novel reaction not previously described. This reaction yields an excellent leaving group in which a primary amine on proteins can substitute to form a covalent bond between a protein and these surfaces. In an earlier study, we demonstrated that collagen IV could be deposited on a modified PTFE surface using EDC as a linker. Once collagen IV is attached to the surface, it assembles to form a functional stratum resembling collagen IV in native basement membrane. In this study, we show data suggesting that the fluorine to carbon ratio determines the acidity of the fluoropolymer surfaces and how well collagen IV attaches to and assembles on four different fluoropolymer surfaces. Copyright © 2011 Wiley Periodicals, Inc.

  2. Microhollow Glow Discharge Instrument for In Situ Lunar Surface Measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and Penn State University (PSU) propose to develop a highly sensitive spectrometer based on glow discharge plasma emission for the...

  3. Modeling plasma glow discharges in Air near a Mach 3 bow shock with KRONOS

    Science.gov (United States)

    Rassou, Sebastien; Labaune, Julien; Packan, Denis; Elias, Paul-Quentin

    2016-09-01

    In this work, plasma glow discharge in Air is modeled near a Mach 3 bow shock. Numerical simulations are performed using the coupling KRONOS which have been developed at ONERA. The flow field is modeled using the code CFD: CEDRE from ONERA and the electrical and plasma part by the EDF open-source code CODE_SATURNE. The plasma kinetic modeling consists on a two-term Boltzmann equation solver and a chemical reaction solver depending of the electric field. The coupling KRONOS is fully parallelized and run on ONERA supercomputers. The shock wave is formed by the propagation of a supersonic flow (M = 3) through a truncated conical model mounted with a central spike. Depending on the spike's voltage value, corona, glow or arc regime could be obtained in a steady flow. The parameters for the supersonic flow and the spike configurations are chosen to be in glow discharge regime and to reproduce the experimental setup. In our simulations, 12 species and 80 reactions (ionization, electronic or vibrational excitation, attachment etc ...) are considered to properly model the glow discharge and the afterglow. In a stationary flow, glow discharge is observed only at the upstream of the shock wave near the high voltage spike. Behind the bow shock, in the afterglow, negative ions are provided by electrons attachment with O2. The negative ions flow convection ensures the electrical conduction and the establishment of the glow discharge.

  4. Coaxial, cylindrical, and planar UV excilamps pumped by glow or barrier discharge

    Science.gov (United States)

    Tarasenko, Victor F.; Lomaev, Mikhail I.; Panchenko, Alexei N.; Sosnin, Edward A.

    1997-03-01

    Design and operating parameters of powerful KrCl((lambda) approximately 222nm), XeCl((lambda) approximately 308nm) excilamps with different discharge geometry pumped by continuous glow discharges along with Ar2((lambda) approximately 126nm) and Kr2((lambda) approximately 146nm) excilamps pumped by barrier discharge are presented. Excilamps with high spatial uniformity of the output and gas lifetime up to 100 hours were developed. It was shown that efficiency of luminescence of exciplex molecules of about 30 percent can be obtained in high-voltage glow discharge and positive column of glow discharge. Output at (lambda) approximately 222nm up to 200 W from single excilamp and 500 W from three excilamps, operated in parallel, was demonstrated.

  5. Endotoxin removal by radio frequency gas plasma (glow discharge)

    Science.gov (United States)

    Poon, Angela

    2011-12-01

    Contaminants remaining on implantable medical devices, even following sterilization, include dangerous fever-causing residues of the outer lipopolysaccharide-rich membranes of Gram-negative bacteria such as the common gut microorganism E. coli. The conventional method for endotoxin removal is by Food & Drug Administration (FDA)-recommended dry-heat depyrogenation at 250°C for at least 45 minutes, an excessively time-consuming high-temperature technique not suitable for low-melting or heat-distortable biomaterials. This investigation evaluated the mechanism by which E. coli endotoxin contamination can be eliminated from surfaces during ambient temperature single 3-minute to cumulative 15-minute exposures to radio-frequency glow discharge (RFGD)-generated residual room air plasmas activated at 0.1-0.2 torr in a 35MHz electrodeless chamber. The main analytical technique for retained pyrogenic bio-activity was the Kinetic Chromogenic Limulus Amebocyte Lysate (LAL) Assay, sufficiently sensitive to document compliance with FDA-required Endotoxin Unit (EU) titers less than 20 EU per medical device by optical detection of enzymatic color development corresponding to LAL Assay of sterile water extracts from both glass and Ge specimens. The Ge prism MAIR-IR measurements were repeated after employing 3-minute RFGD treatments sequentially for more than 10 cycles to observe removal of deposited matter that correlated with diminished EU titers. The results showed that 5 cycles, for a total exposure time of 15 minutes to low-temperature gas plasma, was sufficient to reduce endotoxin titers to below 0.05 EU/ml, and correlated with concurrent reduction of major endotoxin reference standard absorption bands at 3391 cm-1, 2887 cm-1, 1646 cm -1 1342 cm-1, and 1103 cm-1 to less than 0.05 Absorbance Units. Band depletion varied from 15% to 40% per 3-minute cycle of RFGD exposure, based on peak-to-peak analyses. In some cases, 100% of all applied biomass was removed within 5 sequential

  6. Detection of negative ions in glow discharge mass spectrometry for analysis of solid specimens

    DEFF Research Database (Denmark)

    Canulescu, Stela; Molchan, Igor S.; Tauziede, C.

    2010-01-01

    A new method is presented for elemental and molecular analysis of halogen-containing samples by glow discharge time-of-flight mass spectrometry, consisting of detection of negative ions from a pulsed RF glow discharge in argon. Analyte signals are mainly extracted from the afterglow regime...... of the discharge, where the cross section for electron attachment increases. The formation of negative ions from sputtering of metals and metal oxides is compared with that for positive ions. It is shown that the negative ion signals of F(-) and TaO(2)F(-) are enhanced relative to positive ion signals and can...... be used to study the distribution of a tantalum fluoride layer within the anodized tantala layer. Further, comparison is made with data obtained using glow-discharge optical emission spectroscopy, where elemental fluorine can only be detected using a neon plasma. The ionization mechanisms responsible...

  7. Time dependent argon glow discharge treatment of Al-alloy samples

    Indian Academy of Sciences (India)

    A cylindrical discharge chamger of SS 304 with various ports on it, evacuated by turbomoleculer pumping unit is used in the experimental system. A hollow cathode de glow discharge in argon for different time durations is used to treat chemically cleaned ASA 6063 aluminium alloy samples, keeping all other parameters ...

  8. Short-term low-temperature glow discharge nitriding of 316L austenitic steel

    Directory of Open Access Journals (Sweden)

    T. Frączek

    2011-07-01

    Full Text Available The AISI 316L austenitic steel after glow discharge nitriding at temperature of T = 673 K and duration of τ=14,4 ks, for two different variants of specimen arrangement in the glow-discharge chamber was investigated. In order to assess the effectiveness of nitriding process, the surface layers profile analysis examination, surface hardness and hardness profile examination, the analysis of surface layer structures and corrosion resistance tests were performed. It has been found that application of a booster screen effects in a nitrogen diffusion depth increment into the 316L austenitic steel surface, what results in the surface layer thickness escalation.

  9. Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches

    Science.gov (United States)

    Christophorou, L.G.; Hunter, S.R.

    1988-06-28

    An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc. 11 figs.

  10. Neon dc glow discharge at cryogenic cooling: experiment and simulation

    Science.gov (United States)

    Shumova, V. V.; Polyakov, D. N.; Vasilyak, L. M.

    2017-10-01

    The results of the measurement and simulation of electrical characteristics of neon dc discharge are presented. These results have been obtained in the discharge cooled to the temperature of liquid nitrogen (77 K). The experiments were carried out at a neon pressure of 18-187 Pa and a discharge current of 0.01-3.5 mA. Cooling in the subnormal discharge mode at a constant value of discharge current led to a change in the discharge mode. When cooled, the electric field in the positive column and at the boundary of the transition to the normal discharge increased, and the reduced electric field decreased in all the investigated ranges of discharge current, pressure and neon concentration. The simulation of the positive column, based on the diffusion-drift (fluid) model, has shown that the input in the ionization of processes involving excited atoms increases with decreasing discharge temperature.

  11. Effects of glow discharge cleanings on hydrogen isotope removal for plasma facing materials

    Energy Technology Data Exchange (ETDEWEB)

    Yamauchi, Y., E-mail: yamauchi@qe.eng.hokudai.ac.jp [Faculty of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Matsumoto, A.; Kosaka, Y.; Kimura, Y.; Takeda, K. [Graduate School of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Hino, T.; Nobuta, Y. [Faculty of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Nishimura, K. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292 (Japan); Ueda, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2013-07-15

    The effect of the discharge cleanings on hydrogen isotope removal have been evaluated for graphite, stainless steel, tungsten, boron and titanium. For all materials, the helium glow discharge cleaning was the most effective on the hydrogen isotope removal among the inert gas discharges. High efficiency of energy transfer to target atom and deep projected range for helium ion might be responsible for the high removal fraction. The effect of argon glow discharge cleaning was small. The small removal fraction for the argon might be owing to re-deposition layer, which acted as a screening to the removal. The hydrogen isotope in the tungsten was hardly removed by the inert gas discharge cleanings. The small removal fraction for the tungsten might be owing to hydrogen isotope retention in deeper regions resulting from diffusion along with the grain boundary or the porous structure. Surface impurity and morphologies significantly influenced the deuterium removal effects.

  12. High explosives vapor detection by atmospheric sampling glow discharge ionization/tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    McLuckey, S.A.; Goeringer, D.E.; Asano, K.G. [Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.

    1996-02-01

    The combination of atmospheric sampling glow discharge ionization with tandem mass spectrometry for the detection of traces of high explosives is described. Particular emphasis is placed on use of the quadrupole ion trap as the type of tandem mass spectrometer. Atmospheric sampling glow discharge provides a simple, rugged, and efficient means for anion formation while the quadrupole ion trap provides for efficient tandem mass spectrometry. Mass selective ion accumulation and non-specific ion activation methods can be used to overcome deleterious effects arising from ion/ion interactions. Such interactions constitute the major potential technical barrier to the use of the ion trap for real-time monitoring of targeted compounds in uncontrolled and highly variable matrices. Tailored waveforms can be used to effect both mass selective ion accumulation and ion activation. Concatenated tailored waveforms allow for both functions in a single experiment thereby providing the capability for monitoring several targeted species simultaneously. The combination of atmospheric sampling glow discharge ionization with a state-of-the-art analytical quadrupole ion trap is a highly sensitive and specific detector for traces of high explosives. The combination is also small and inexpensive relative to virtually any other form of tandem mass spectrometry. The science and technology underlying the glow discharge/ion trap combination is sufficiently mature to form the basis for an engineering effort to make the detector portable. 85 refs.

  13. Plasma Processing with a One Atmosphere Uniform Glow Discharge Plasma (OAUGDP)

    Science.gov (United States)

    Reece Roth, J.

    2000-10-01

    The vast majority of all industrial plasma processing is conducted with glow discharges at pressures below 10 torr. This has limited applications to high value workpieces as a result of the large capital cost of vacuum systems and the production constraints of batch processing. It has long been recognized that glow discharges would play a much larger industrial role if they could be operated at one atmosphere. The One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) has been developed at the University of Tennessee Plasma Sciences Laboratory. The OAUGDP is non-thermal RF plasma with the time-resolved characteristics of a classical low pressure DC normal glow discharge. An interdisciplinary team was formed to conduct exploratory investigations of the physics and applications of the OAUGDP. This team includes collaborators from the UTK Textiles and Nonwovens Development Center (TANDEC) and the Departments of Electrical and Computer Engineering, Microbiology, Food Science and Technology, and Mechanical and Aerospace Engineering and Engineering Science. Exploratory tests were conducted on a variety of potential plasma processing and other applications. These include the use of OAUGDP to sterilize medical and dental equipment and air filters; diesel soot removal; plasma aerodynamic effects; electrohydrodynamic (EDH) flow control of the neutral working gas; increasing the surface energy of materials; increasing the wettability and wickability of fabrics; and plasma deposition and directional etching. A general overview of these topics will be presented.

  14. Nonlocal control of electron temperature in short direct current glow discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Demidov, V. I. [Department of Optics and Spectroscopy, St. Petersburg State University, St. Petersburg 199034 (Russian Federation); International Laboratory “Nonlocal Plasma in Nanotechnology and Medicine”, ITMO University, Kronverkskiy pr. 49, St. Petersburg 197101 (Russian Federation); Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States); Kudryavtsev, A. A.; Stepanova, O. M. [Department of Optics and Spectroscopy, St. Petersburg State University, St. Petersburg 199034 (Russian Federation); Kurlyandskaya, I. P. [International Laboratory “Nonlocal Plasma in Nanotechnology and Medicine”, ITMO University, Kronverkskiy pr. 49, St. Petersburg 197101 (Russian Federation); St. Petersburg University of State Fire Service of EMERCOM RF, Murmansk Branch, Murmansk 183040 (Russian Federation)

    2014-09-15

    To demonstrate controlling the electron temperature in nonlocal plasma, experiments have been performed on a short (without positive column) dc glow discharge with a cold cathode by applying different voltages to the conducting discharge wall. The experiments have been performed for low-pressure noble gas discharges. The applied voltage can modify trapping the energetic electrons emitted from the cathode sheath and arising from the atomic and molecular processes in the plasma within the device volume. This phenomenon results in the energetic electrons heating the slow plasma electrons, which consequently modifies the electron temperature. Furthermore, a numerical model of the discharge has demonstrated the electron temperature modification for the above case.

  15. Monte Carlo Simulation of Normal and Abnormal Glow Discharge Plasmas Using the Limited Weight Probability Method

    Science.gov (United States)

    Goto, Makoto; Kondoh, Yoshiomi

    1998-01-01

    A self-consistent Monte Carlo modelling technique has been developed to study normal and abnormal glow discharge plasmas. To simulate nonequilibrium particles, a limited weight probability method is introduced and a fine subslab system is used. These two methods are applied to a DC Ar-like gas discharge simulation. The simulations are performed for conditions corresponding to the experimental voltage and current sets of normal and abnormal glow disharges. The characteristic spatial profiles of plasmas for normal and abnormal glow discharges with high nonequilibrium electron energy distributions are obtained. The increase in the current and the voltage from the normal glow leads to the following: (1) the density peak of the ions rises in the cathode region, (2) the density peak of electrons rises and catches up with that of ions and the peak position occurs closer to the cathode simultaneously; instead of a small increase of plasma density in the bulk plasma region, (3) reversal field strength next to the cathode fall increases and (4) the two groups of the enregy distribution separates into three groups at the cathode fall edge.

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

    Science.gov (United States)

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

    2018-01-01

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

  17. Electric regimes and luminescent behavior of D C air glow discharge plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Delgado-Aparicio V, L.F. [Pontificia Universidad Catolica del Peru, Lima (Peru). Seccion Fisica. Grupo de Investigacion en Plasmas. E-mail: plasma@pucp.edu.pe

    1998-07-01

    A study of the electric regimes or modes with a brief summary on their dependence with the eight luminescent zones (between dark and glowing ones) of a DC air glow discharge plasma is presented. This research, carried out as part of a thesis, describes the electric behavior of the discharge through potential, current and resistance measurements. With these, we explain the strong dependence of the subnormal, normal and abnormal regimes with pressure and gap separation. Also we can correlate the previous conclusions with the luminescent analysis that we had made, finding that varying the pressure varies the length and luminous intensity of the three principal mechanisms in the discharge: the cathode and anode fall, and in between them, the positive column. (author)

  18. Elimination of inter-discharge helium glow discharge cleaning with lithium evaporation in NSTX

    Directory of Open Access Journals (Sweden)

    R. Maingi

    2017-08-01

    Full Text Available Operation in the National Spherical Torus Experiment (NSTX typically used either periodic boronization and inter-shot helium glow discharge cleaning (HeGDC, or inter-shot lithium evaporation without boronization, and initially with inter-shot HeGDC. To assess the viability of operation without HeGDC, dedicated experiments were conducted in which Li evaporation was used while systematically shrinking the HeGDC between shots from the standard 10min to zero (10→6.5→4→0. Good shot reproducibility without HeGDC was achieved with lithium evaporations of 100mg or higher; evaporations of 200–300mg typically resulted in very low ELM frequency or ELM-free operation, reduced wall fueling, and improved energy confinement. The use of HeGDC before lithium evaporation modestly reduced Dα in the outer scrape-off layer, but not at the strike point. Pedestal electron and ion temperature also improved modestly, suggesting that HeGDC prior to lithium evaporation is a useful tool for experiments that seek to maximize plasma performance.

  19. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    OpenAIRE

    Pai, David,; Lacoste, Deanna,; Laux, C.

    2010-01-01

    International audience; In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determine...

  20. Elongated dust particles growth in a spherical glow discharge in ethanol

    Science.gov (United States)

    Fedoseev, A. V.; Sukhinin, G. I.; Sakhapov, S. Z.; Zaikovskii, A. V.; Novopashin, S. A.

    2018-01-01

    The formation of elongated dust particles in a spherical dc glow discharge in ethanol was observed for the first time. Dust particles were formed in the process of coagulation of ethanol dissociation products in the plasma of gas discharge. During the process the particles were captured into clouds in the electric potential wells of strong striations of spherical discharge. The size and the shape of dust particles are easily detected by naked eye after the illumination of the laser sheet. The description of the experimental setup and conditions, the analysis of size, shape and composition of the particles, the explanation of spatial ordering and orientation of these particles are presented.

  1. Slow electron energy balance for hybrid models of direct-current glow discharges

    Science.gov (United States)

    Eliseev, S. I.; Bogdanov, E. A.; Kudryavtsev, A. A.

    2017-09-01

    In this paper, we present the formulation of slow electron energy balance for hybrid models of direct current (DC) glow discharge. Electrons originating from non-local ionization (secondary) contribute significantly to the energy balance of slow electrons. An approach towards calculating effective energy brought by a secondary electron to the group of slow electrons by means of Coulomb collisions is suggested. The value of effective energy shows a considerable dependence on external parameters of a discharge, such as gas pressure, type, and geometric parameters. The slow electron energy balance was implemented into a simple hybrid model that uses analytical formulation for the description of non-local ionization by fast electrons. Simulations of short (without positive column) DC glow discharge in argon are carried out for a range of gas pressures. Comparison with experimental data showed generally good agreement in terms of current-voltage characteristics, electron density, and electron temperature. Simulations also capture the trend of increasing electron density with decreasing pressure observed in the experiment. Analysis shows that for considered conditions, the product of maximum electron density ne and electron temperature Te in negative glow is independent of gas pressure and depends on the gas type, cathode material, and discharge current. Decreasing gas pressure reduces the heating rate of slow electrons during Coulomb collisions with secondary electrons, which leads to lower values of Te and, in turn, higher maximum ne.

  2. Measurement and analysis for optical radiation of glow discharge plasma at atmospheric pressure

    Science.gov (United States)

    Ren, Qinglei; Lin, Qi

    2006-02-01

    The optical radiation measurement and analysis to the glow discharge plasma at atmospheric pressure have been done in the paper. The low temperature plasma due to atmospheric pressure glow discharge (APGD) in air has been produced on the planar surface of designed electrode plate. The optical radiation spectra of the plasma produced in two kinds of electrode plats with different power values loaded have been measured and sampled with the minitype grating spectrograph system. The acquired spectra data are processed averagely and analyzed. The results of analysis indicate that the optical characteristic of the APGD plasma is related to the loaded power and layout of the electrode plate. This shows that it is feasible to describe the characteristic parameters of APGD plasma qualitatively and control the strength of the APGD plasma quantitatively by the obtained relationship, which provides a convenient approach for utilizing APGD plasma effectively and also establishes some foundation to investigate APGD plasma further.

  3. Effective secondary electron emission coefficient in DC abnormal glow discharge plasmas

    Science.gov (United States)

    Arumugam, Saravanan; Alex, Prince; Sinha, Suraj Kumar

    2017-11-01

    In this work, a self-consistent model has been used to estimate the effective secondary electron emission coefficient (γE) of the cathode in typical abnormal dc glow discharge conditions. Using this model, the value of γE has been obtained for tungsten (W), copper (Cu), and stainless steel (SS304) cathode samples for argon (Ar) and nitrogen (N2) discharges. The γE for W is lower than the Cu cathode under identical operating conditions. The results show possible dependence of γE on the Fermi energy of the cathode material since it influences the probability of electron to be emitted by the incident ion. In addition to this, we found, significant contribution of cathode directed species other than ion to γE. Further, the effect of pressure on γE for the N2 discharge has been investigated in the pressure range of 0.5 mbar to 2.0 mbar and its value increases from 0.38 to 0.47 with pressure for the SS304 cathode. The knowledge of γE successfully explains the governing processes in abnormal glow discharge plasma that cannot be explained by the value of the ion induced secondary electron emission coefficient γi. The measurement of the γE value of the cathode material in typical abnormal glow discharge plasma conditions presents possibilities of exciting advancement in various applications by accurate estimation of discharge characteristics including flux of species, fraction of power carried by ions and electrons, plasma density, discharge current density, etc.

  4. Ethanol reforming in non-equilibrium plasma of glow discharge

    CERN Document Server

    Levko, D

    2012-01-01

    The results of a detailed kinetic study of the main plasma chemical processes in non-equilibrium ethanol/argon plasma are presented. It is shown that at the beginning of the discharge the molecular hydrogen is mainly generated in the reaction of ethanol H-abstraction. Later hydrogen is formed from active H, CH2OH and CH3CHOH and formaldehyde. Comparison with experimental data has shown that the used kinetic mechanism predicts well the concentrations of main species at the reactor outlet.

  5. Charging of dust grains in a nonequilibrium plasma of a stratified glow discharge

    Science.gov (United States)

    Sukhinin, G. I.; Fedoseev, A. V.

    2007-12-01

    A theoretical model is presented that describes the charging of dust grains in the positive plasma column of a stratified glow dc discharge in argon. A one-dimensional self-consistent model is used to obtain axial profiles of the electric field, as well as the electron energy distribution function along the axis of the discharge tube. Radial profiles of the electric field are determined in the ambipolar diffusion approximation. It is assumed that, in the radial direction, the electron distribution function depends only on the total electron energy. Two-dimensional distributions of the discharge plasma parameters are calculated and used to determine the potential and charge of a test dust grain at a certain point within the discharge and the electrostatic forces acting on it. It is shown that the grain charge distribution depends strongly on the nonequilibrium electron distribution function and on the nonuniform distribution of the electric field in a stratified glow discharge. A discussion is presented on the suspension of dust grains, the separation of grains by size in the discharge striations, and a possible mechanism for the onset of vortex dust motion at the edge of a dust cloud.

  6. Non-linear macro evolution of a dc driven micro atmospheric glow discharge

    Science.gov (United States)

    Xu, S. F.; Zhong, X. X.

    2015-10-01

    We studied the macro evolution of the micro atmospheric glow discharge generated between a micro argon jet into ambient air and static water. The micro discharge behaves similarly to a complex ecosystem. Non-linear behaviors are found for the micro discharge when the water acts as a cathode, different from the discharge when water behaves as an anode. Groups of snapshots of the micro discharge formed at different discharge currents are captured by an intensified charge-coupled device with controlled exposure time, and each group consisted of 256 images taken in succession. Edge detection methods are used to identify the water surface and then the total brightness is defined by adding up the signal counts over the area of the micro discharge. Motions of the water surface at different discharge currents show that the water surface lowers increasingly rapidly when the water acts as a cathode. In contrast, the water surface lowers at a constant speed when the water behaves as an anode. The light curves are similar to logistic growth curves, suggesting that a self-inhibition process occurs in the micro discharge. Meanwhile, the total brightness increases linearly during the same time when the water acts as an anode. Discharge-water interactions cause the micro discharge to evolve. The charged particle bomb process is probably responsible for the different behaviors of the micro discharges when the water acts as cathode and anode.

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

    Science.gov (United States)

    Reece Roth, J.

    2004-11-01

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

  8. Stabilization of a cold cathode electron beam glow discharge for surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Mingolo, N.; Gonzalez, C.R. [Lab. de Haces Dirigidos, Depto. de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Martinez, O.E. [Lab. de Electronica Cuantica, Depto. de Fisica, Universidad de Buenos Aires, Pabellon 1, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Rocca, J.J. [Department of Electrical Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States)

    1997-10-01

    We have demonstrated that the reproducibility of electron beam pulses generated by a high power, cold cathode glow discharge is greatly improved by adding a small continuous keep-alive discharge current. A current of the order of 200 {mu}A was found to limit the shot to shot current variation to within 1.5{percent}. This stabilization in turn reduces by an order of magnitude the fluctuations of the energy density deposited on the target, demonstrating a reliable energy source for surface treatment. {copyright} {ital 1997 American Institute of Physics.}

  9. Charge mitigation techniques using glow and corona discharges for advanced gravitational wave detectors

    Science.gov (United States)

    Campsie, P.; Cunningham, L.; Hendry, M.; Hough, J.; Reid, S.; Rowan, S.; Hammond, G. D.

    2011-11-01

    Charging of silica test masses in gravitational wave detectors could potentially become a significant low-frequency noise source for advanced detectors. Charging noise has already been observed and confirmed in the GEO600 detector and is thought to have been observed in one of the LIGO detectors. In this paper, two charge mitigation techniques using glow and corona discharges were investigated to create repeatable and robust procedures. The glow discharge procedure was used to mitigate charge under vacuum and would be intended to be used in the instance where an optic has become charged while the detector is in operation. The corona discharge procedure was used to discharge samples at atmospheric pressure and would be intended to be used to discharge the detector optics during the cleaning of the optics. Both techniques were shown to reduce both polarities of surface charge on fused silica to a level that would not limit advanced LIGO. Measurements of the transmission of samples that had undergone the charge mitigation procedures showed no significant variation in transmission, at a sensitivity of ~ 200 ppm, in TiO2-doped Ta2O5/SiO2 multi-layer coated fused silica.

  10. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    Science.gov (United States)

    Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-05-01

    In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determined, with the notable result that there exists a minimum and maximum gap distance for its existence at a given ambient gas temperature. The minimum gap distance increases with decreasing gas temperature, whereas the maximum does not vary appreciably. To explain the experimental results, an analytical model is developed to explain the corona-to-glow (C-G) and glow-to-spark (G-S) transitions. The C-G transition is analyzed in terms of the avalanche-to-streamer transition and the breakdown field during the conduction phase following the establishment of a conducting channel across the discharge gap. The G-S transition is determined by the thermal ionization instability, and we show analytically that this transition occurs at a certain reduced electric field for the NRP discharges studied here. This model shows that the electrode geometry plays an important role in the existence of the NRP glow regime at a given gas temperature. We derive a criterion for the existence of the NRP glow regime as a function of the ambient gas temperature, pulse repetition frequency, electrode radius of curvature, and interelectrode gap distance.

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

    Energy Technology Data Exchange (ETDEWEB)

    Prevosto, L., E-mail: prevosto@waycom.com.ar; Mancinelli, B.; Chamorro, J. C.; Cejas, E. [Grupo de Descargas Eléctricas, Departamento Ing. Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto (2600), Santa Fe (Argentina); Kelly, H. [Grupo de Descargas Eléctricas, Departamento Ing. Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto (2600), Santa Fe (Argentina); Instituto de Física del Plasma (CONICET), Facultad de Ciencias Exactas y Naturales (UBA) Ciudad Universitaria Pab. I, 1428, Buenos Aires (Argentina)

    2015-02-15

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

  12. Boltzmann statistical consideration on the excitation mechanism of iron atomic lines emitted from glow discharge plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lei; Kashiwakura, Shunsuke; Wagatsuma, Kazuaki, E-mail: wagatuma@imr.tohoku.ac.jp

    2011-11-15

    A Boltzmann plot for many iron atomic lines having excitation energies of 3.3-6.9 eV was investigated in glow discharge plasmas when argon or neon was employed as the plasma gas. The plot did not show a linear relationship over a wide range of the excitation energy, but showed that the emission lines having higher excitation energies largely deviated from a normal Boltzmann distribution whereas those having low excitation energies (3.3-4.3 eV) well followed it. This result would be derived from an overpopulation among the corresponding energy levels. A probable reason for this is that excitations for the high-lying excited levels would be caused predominantly through a Penning-type collision with the metastable atom of argon or neon, followed by recombination with an electron and then stepwise de-excitations which can populate the excited energy levels just below the ionization limit of iron atom. The non-thermal excitation occurred more actively in the argon plasma rather than the neon plasma, because of a difference in the number density between the argon and the neon metastables. The Boltzmann plots yields important information on the reason why lots of Fe I lines assigned to high-lying excited levels can be emitted from glow discharge plasmas. - Highlights: Black-Right-Pointing-Pointer This paper shows the excitation mechanism of Fe I lines from a glow discharge plasma. Black-Right-Pointing-Pointer A Boltzmann distribution is studied among iron lines of various excitation levels. Black-Right-Pointing-Pointer We find an overpopulation of the high-lying energy levels from the normal distribution. Black-Right-Pointing-Pointer It is caused through Penning-type collision of iron atom with argon metastable atom.

  13. Cathodic contact glow discharge electrolysis: its origin and non-faradaic chemical effects

    Science.gov (United States)

    Gupta, Susanta K. Sen; Singh, Rajshree

    2017-01-01

    Normal electrolysis (NE), at sufficiently high voltages, breaks down and undergoes a transition to a phenomenon called contact glow discharge electrolysis (CGDE) in which a sheath of glow discharge plasma encapsulates one of the electrodes, the anode or the cathode. The chemical effects of CGDE are highly non-faradaic e.g. a mixture of H2 and H2O2 plus O2 each in excess of the Faraday law value is liberated at the glow discharge plasma electrode from an aqueous electrolyte solution. Studies of cathodic CGDE, particularly its origin and chemical effects, in comparison to those of anodic CGDE have received significantly less attention and have not been studied in detail. The present paper is an attempt towards elucidation of the mechanisms of the growth of cathodic CGDE during NE and its non-faradaic chemical effects. The findings of the study have led to the inference that emission of secondary electrons from the metal cathode with sufficient kinetic energies, vaporization of the electrolyte solvent in the vicinity of the cathode surface induced by Joule heating and the onset of hydrodynamic instabilities in local vaporization contribute to the generation of the plasma at the cathode during NE. The findings have further shown that non-faradaic yields of CGDE at the cathode originate from energy transfer processes in two reaction zones: a plasma phase reaction zone around the cathode which accounts for ~75% of the yields, and a liquid phase reaction zone near the plasma-catholyte solution interface accounting for the remaining ~25% of the yields.

  14. Hydrogen in carbon foils made by DC glow discharge in ethylene

    Science.gov (United States)

    Bailey, P.; Armour, D. G.; England, J. B. A.; Tait, N. R. S.; Tolfree, D. W. L.

    1983-08-01

    Thermal desorption has been studied from thin films of carbon prepared by dc glow discharge in ethylene. The only gases released in significant quantities are hydrogen and methane. Both releases can be characterised by a continuum of activation energies but the methane release peaks at a lower temperature than that from hydrogen. The estimated total hydrogen release is compared with the hydrogen content determined by nuclear scattering experiments. Infra red studies suggest that the majority of CH 2 and CH 3 bonds can be ruptured by annealing at 300°C, a temperature well below the hydrogen and methane release rate maxima. Possible hydrogen bonding modes and desorption mechanisms are discussed.

  15. Surface modification of austenitic steel by various glow-discharge nitriding methods

    Directory of Open Access Journals (Sweden)

    Tomasz Borowski

    2015-09-01

    Full Text Available Recent years have seen intensive research on modifying glow-discharge nitriding processes. One of the most commonly used glow-discharge methods includes cathodic potential nitriding (conventional method, and active screen plasma nitriding. Each of these methods has a number of advantages. One very important, common feature of these techniques is full control of the microstructure, chemical and phase composition, thickness and the surface topography of the layers formed. Another advantage includes the possibility of nitriding such materials as: austenitic steels or nickel alloys, i.e. metallic materials which do not diffuse nitrogen as effectively as ferritic or martensitic steels. However, these methods have some disadvantages as well. In the case of conventional plasma nitriding, engineers have to deal with the edge effect, which makes it difficult to use this method for complexly shaped components. In turn, in the case of active screen plasma nitriding, the problem disappears. A uniform, smooth layer forms, but is thinner, softer and is not as resistant to friction compared to layers formed using the conventional method. Research is also underway to combine these methods, i.e. use an active screen in conventional plasma nitriding at cathodic potential. However, there is a lack of comprehensive data presenting a comparison between these three nitriding processes and the impact of pulsating current on the formation of the microstructure and functional properties of austenitic steel surfaces. The article presents a characterisation of nitrided layers produced on austenitic X2CrNiMo17-12-2 (AISI 316L stainless steel in the course of glow-discharge nitriding at cathodic potential, at plasma potential and at cathodic potential incorporating an active screen. All processes were carried out at 440 °C under DC glow-discharge conditions and in 100 kHz frequency pulsating current. The layers were examined in terms of their microstructure, phase and

  16. Transmission characteristics of microwave in a glow-discharge dusty plasma

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Jieshu; Yuan, Chengxun, E-mail: yuancx@hit.edu.cn; Gao, Ruilin; Wang, Ying; Zhou, Zhong-Xiang [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Liu, Sha; Yue, Feng [Shanghai Institute of Spaceflight Control Technology, Shanghai 200233 (China); Wu, Jian [China Research Institute of Radio wave Propagation, Qingdao 102206 (China); Li, Hui [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); China Research Institute of Radio wave Propagation, Qingdao 102206 (China)

    2016-07-15

    In this study, the propagation characteristics of electromagnetic wave in a glow discharge plasma with dust particles are experimentally investigated. A helium alternating current glow discharge plasmas have been successfully generated. Measurements of the plasma parameters using Langmuir probes, in the absence of dust particles, provide plasma densities (n{sub e}) of 10{sup 17 }m{sup −3} and electron temperatures (T{sub e}) ranging from 2 to 4 eV. Dusty plasmas are made by adding 30 nm radius aluminum oxide (Al{sub 2}O{sub 3}) particles into the helium plasma. The density of the dust particle (n{sub d}) in the device is about 10{sup 11}–10{sup 12 }m{sup −3}. The propagation characteristics of electromagnetic waves are determined by a vector network analyzer with 4–6 GHz antennas. An apparent attenuation by the dust is observed, and the measured attenuation data are approximately in accordance with the theoretical calculations. The effects of gas pressure and input power on the propagation are also investigated. Results show that the transmission attenuation increases with the gas pressure and input power, the charged dust particles play a significant role in the microwave attenuation.

  17. Glow discharge optical emission spectroscopy for accurate and well resolved analysis of coatings and thin films

    KAUST Repository

    Wilke, Marcus

    2011-12-01

    In the last years, glow discharge optical emission spectrometry (GDOES) gained more and more acceptance in the analysis of functional coatings. GDOES thereby represents an interesting alternative to common depth profiling techniques like AES and SIMS, based on its unique combination of high erosion rates and erosion depths, sensitivity, analysis of nonconductive layers and easy quantification even for light elements such as C, N, O and H. Starting with the fundamentals of GDOES, a short overview on new developments in instrument design for accurate and well resolved thin film analyses is presented. The article focuses on the analytical capabilities of glow discharge optical emission spectrometry in the analysis of metallic coatings and thin films. Results illustrating the high depth resolution, confirmation of stoichiometry, the detection of light elements in coatings as well as contamination on the surface or interfaces will be demonstrated by measurements of: a multilayer system Cr/Ti on silicon, interface contamination on silicon during deposition of aluminum, Al2O3-nanoparticle containing conversion coatings on zinc for corrosion resistance, Ti3SiC2 MAX-phase coatings by pulsed laser deposition and hydrogen detection in a V/Fe multilayer system. The selected examples illustrate that GDOES can be successfully adopted as an analytical tool in the development of new materials and coatings. A discussion of the results as well as of the limitations of GDOES is presented. © 2011 Elsevier B.V.

  18. Decomposition of toluene in a steady-state atmospheric-pressure glow discharge

    Science.gov (United States)

    Trushkin, A. N.; Grushin, M. E.; Kochetov, I. V.; Trushkin, N. I.; Akishev, Yu. S.

    2013-02-01

    Results are presented from experimental studies of decomposition of toluene (C6H5CH3) in a polluted air flow by means of a steady-state atmospheric pressure glow discharge at different water vapor contents in the working gas. The experimental results on the degree of C6H5CH3 removal are compared with the results of computer simulations conducted in the framework of the developed kinetic model of plasma chemical decomposition of toluene in the N2: O2: H2O gas mixture. A substantial influence of the gas flow humidity on toluene decomposition in the atmospheric pressure glow discharge is demonstrated. The main mechanisms of the influence of humidity on C6H5CH3 decomposition are determined. The existence of two stages in the process of toluene removal, which differ in their duration and the intensity of plasma chemical decomposition of C6H5CH3 is established. Based on the results of computer simulations, the composition of the products of plasma chemical reactions at the output of the reactor is analyzed as a function of the specific energy deposition and gas flow humidity. The existence of a catalytic cycle in which hydroxyl radical OH acts a catalyst and which substantially accelerates the recombination of oxygen atoms and suppression of ozone generation when the plasma-forming gas contains water vapor is established.

  19. Borax as flux on sintering of iron Ancor Steel 1000® under glow discharge

    Science.gov (United States)

    Ariza Suarez, H. G.; Sarmiento Santos, A.; Ortiz Otálora, C. A.

    2016-02-01

    This work studies the flux effect of borax (di sodium tetraborate decahydrate) on sintering of iron Ancor Steel 1000® in abnormal glow discharge. The incidence of the percentage by weight of borax and the sintering temperature in the process were observed. Samples of powder metallurgical iron were prepared with proportions of 0.50%, 2.0%, 4.0% and 6.0% by weight of borax using the procedures of powder metallurgy. The samples were sintered at 800 and 1100°C for 30min, by glow discharge at low pressure in a reducing atmosphere composed of 20% H2+80% Ar. The samples in compact green-state were analyzed by TGA-DSC to determine the fusion process and mass loss during sintering. The analysis of microhardness and density, shows that at a sintering temperature of 800°C the sample density decreases and the sample microhardness increases with respect to sintered samples without borax. Sintered samples were analysed by DRX showing the absence of precipitates.

  20. Laser-induced optogalvanic signal oscillations in miniature neon glow discharge plasma.

    Science.gov (United States)

    Saini, V K

    2013-06-20

    Laser-induced optogalvanic (OG) signal oscillations detected in miniature neon glow discharge plasma are investigated using a discharge equivalent-circuit model. The damped oscillations in OG signal are generated when a pulsed dye laser is tuned to a specific neon transition (1s5→2p2) at 588.2 nm under the discharge conditions where dynamic resistance changes its sign. Penning ionization via quasi-resonant energy transfer collisions between neon gas atoms in metastable state and sputtered electrode atoms in ground state is discussed to explain the negative differential resistance properties of discharge plasma that are attributed to oscillations in the OG signal. The experimentally observed results are simulated by analyzing the behavior of an equivalent discharge-OG circuit. Good agreement between theoretically calculated and experimental results is observed. It is found that discharge plasma is more sensitive and less stable in close vicinity to dynamic resistance sign inversion, which can be useful for weak-optical-transition OG detection.

  1. Irradiation of silver and agar/silver nanoparticles with argon, oxygen glow discharge plasma, and mercury lamp.

    Science.gov (United States)

    Ahmad, Mahmoud M; Abdel-Wahab, Essam A; El-Maaref, A A; Rawway, Mohammed; Shaaban, Essam R

    2014-01-01

    The irradiation effect of argon, oxygen glow discharge plasma, and mercury lamp on silver and agar/silver nanoparticle samples is studied. The irradiation time dependence of the synthesized silver and agar/silver nanoparticle absorption spectra and their antibacterial effect are studied and compared. In the agar/silver nanoparticle sample, as the irradiation time of argon glow discharge plasma or mercury lamp increases, the peak intensity and the full width at half maximum, FWHM, of the surface plasmon resonance absorption band is increased, however a decrease of the peak intensity with oxygen glow plasma has been observed. In the silver nanoparticle sample, as the irradiation time of argon, oxygen glow discharge plasma or mercury lamp increases, the peak intensity of the surface plasmon resonance absorption band is increased, however, there is no significant change in the FWHM of the surface plasmon resonance absorption band. The SEM results for both samples showed nanoparticle formation with mean size about 50 nm and 40 nm respectively. Throughout the irradiation time with the argon, oxygen glow discharge plasma or mercury lamp, the antibacterial activity of several kinds of Gram-positive and Gram-negative bacteria has been examined.

  2. Degradation of methyl tert-butyl ether (MTBE) in water by glow discharge plasma.

    Science.gov (United States)

    Tong, Shaoping; Ni, Yanyan; Shen, Chensi; Wen, Yuezhong; Jiang, Xuanzhen

    2011-01-01

    This study evaluated the ability of the glow discharge plasma (GDP) technique to degrade methyl tert-butyl ether (MTBE) in an aqueous solution. The results showed that a large amount of hydrogen peroxide and highly active *OH free radicals were produced during the treatment. Various experimental parameters including discharge current, initial MTBE concentration and initial pH played significant roles on MTBE degradation. In addition, Fe2+ had a catalytic effect on the degradation of MTBE, which is potentially attributable to the reaction between Fe3+ and the hydrated electron. It was also confirmed that GDP was comparable to electrocatalytic oxidation and high-density plasma and more efficient than photocatalytic degradation techniques. These results suggest that GDP may become a competitive MTBE wastewater treatment technology.

  3. Isotopic abundance measurements on solid nuclear-type samples by glow discharge mass spectrometry.

    Science.gov (United States)

    Betti, M; Rasmussen, G; Koch, L

    1996-07-01

    A double-focusing Glow Discharge Mass Spectrometer (GDMS) installed in a glovebox for nuclear sample screening has been employed for isotopic measurements. Isotopic compositions of zirconium, silicon, lithium, boron, uranium and plutonium which are elements of nuclear concern have been determined. Interferences arising from the matrix sample and the discharge gas (Ar) for each of these elements are discussed. The GDMS results are compared with those from Thermal Ionization Mass Spectrometry (TIMS). For boron and lithium at microg/g-ng/g levels, the two methods gave results in good agreement. In samples containing uranium the isotopic composition obtained by GDMS was in agreement with those from TIMS independently of the enrichment. Attempts for the determination of plutonium isotopic composition were also made. In this case, due to the interferences of uranium at mass 238 and americium at mass 241, the GDMS raw data are complementary with those values obtained from physical non-destructive techniques.

  4. Plasma nitriding of aluminium in a pulsed dc glow discharge of nitrogen

    Science.gov (United States)

    Naseer, S.; Khan, F. U.; Rehman, N. U.; Qayyum, A.; Rahman, F.; Zakaullah, M.

    2010-02-01

    Plasma nitriding of aluminium in a 50 Hz pulsed-dc glow discharge is studied for different ion-current densities (2.0-5.0 mA cm-2) by keeping the corresponding discharge parameters such as treatment time, chamber pressure, substrate temperature and gas composition same. The treated samples are analysed for changes induced in surface properties using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Vickers's micro-hardness testing. XRD showed the downshift in the original diffraction peak corresponding to (111) plane reflection along with the emergence of new diffraction peak corresponding to (220) plane reflection, confirming the N-diffusion into existing Al-lattice and formation of AlN compound. Surface hardness is significantly improved which might be attributed to the diffusion of nitrogen and compound layer formation.

  5. Time-delayed transition of normal-to-abnormal glow in pin-to-water discharge

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, S.-Y.; Byeon, Y.-S.; Yoo, S.; Hong, E. J.; Kim, S. B.; Yoo, S. J.; Ryu, S., E-mail: smryu@nfri.re.kr [Plasma Technology Research Center of National Fusion Research Institute, 37, Dongjangsan-ro, Gunsan-si, Jeollabuk-do, Gunsan 54004 (Korea, Republic of)

    2016-08-15

    Time-delayed transition of normal-to-abnormal glow was investigated in discharge between spoke-like pins and ultrapure water by applying AC-driven power at a frequency of 14.3 kHz at atmospheric pressure. The normal-to-abnormal transition can be recognized from the slope changes of current density, gas temperature, electrode temperature, and OH density. The slope changes took place in tens of minutes rather than just after discharge, in other words, the transition was delayed. The time-delay of the transition was caused by the interaction between the plasma and water. The plasma affected water properties, and then the water affected plasma properties.

  6. The hydrogen and oxygen content of self-supporting carbon foils prepared bydc glow discharge in ethylene

    Science.gov (United States)

    Tait, N. R. S.; Tolfree, D. W. L.; John, P.; Odeh, I. M.; Thomas, M. J. K.; Tricker, M. J.; Wilson, J. I. B.; England, J. B. A.; Newton, D.

    1980-10-01

    The hydrogen and oxygen content of self-supporting carbon films produced bydc glow discharge have been determined using a precise method involving the elastic scattering of 25 MeV α-particles. The number of carbon-hydrogen bonds has been determined for similar samples using infra-red spectroscopy. The results are compared with those for samples made by the carbon arc process. Assuming that the glow discharge carbon contains graphitic regions surrounded by amorphous tetrahedrally bonded material to which hydrogen can attach, a simple estimate is made of the relative numbers of carbon atoms in the two forms.

  7. Non-local effects in a stratified glow discharge with dust particles

    Energy Technology Data Exchange (ETDEWEB)

    Sukhinin, G I; Fedoseev, A V [Institute of Thermophysics SB RAS, Lavrentyev Ave., 1, Novosibirsk, 630090 (Russian Federation); Ramazanov, T S; Amangaliyeva, R Zh; Dosbalayev, M K; Jumabekov, A N [Institute of Experimental and Theoretical Physics, Al Farabi Kazakh National University, Tole Bi, 96a, Almaty, 050012 (Kazakhstan)], E-mail: fedoseev@itp.nsc.ru

    2008-12-21

    The work is aimed at describing non-local effects in the positive column of a low-pressure stratified dc glow discharge in argon with dust particles in a vertical cylindrical discharge tube. Numerical calculations of plasma parameters in the axis of the discharge tube were performed with the help of a hybrid model based on the solution of a non-local Boltzmann equation for electron energy distribution function (EEDF). Axial distributions of optical emission from striations with dust particles were measured experimentally. Negatively charged dust particles in a low-pressure stratified gas discharge should levitate at the anode-side branch of an electric field distribution above its maximum. At the same time the experiments showed that the dust particles levitate at the cathode side of a stratum. This paradox is explained by the fact that in a low-pressure striated discharge the optical emission distribution is displaced relative to the electric field distribution that was shown both by numerical simulations and experimental measurements.

  8. A study of the glow discharge plasma jet of the novel Hamburger-electrode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenzheng, E-mail: wzhliu@bjtu.edu.cn; Ma, Chuanlong, E-mail: 15121452@bjtu.edu.cn; Yang, Xiao; Cui, Weisheng; Chen, Xiuyang [School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044 (China)

    2016-08-15

    To generate atmospheric pressure glow discharge plasma jets (APGDPJs), a novel Hamburger-electrode was proposed. Through the study on electric field distributions, flow field distributions, and characteristics of the discharge and jet, we found that adopting the mode of dielectric barrier discharge with non-uniform thickness of dielectric, it was easy to form the strong electric field areas which were conducive to generate discharge and electric field distributions with large electric field intensity in the narrow gap and weak electric field intensity in the wide gap that were not inclined to form a filament discharge. Using the structure of evenly distributed inner electrodes, it was easy to weaken the pressure of strong electric field areas and form flow field distributions which is beneficial for taking out the high density charged particles and generating APGDPJs. Stable APGDPJs in nitrogen with 3.5 mm in diameter and 9 mm in length were formed by using the novel Hamburger-electrode.

  9. Atmospheric-pressure solution-cathode glow discharge: A versatile ion source for atomic and molecular mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Andrew J. [Department of Chemistry, Indiana University, Bloomington, IN, 47405 (United States); Williams, Kelsey L. [Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242 (United States); Hieftje, Gary M. [Department of Chemistry, Indiana University, Bloomington, IN, 47405 (United States); Shelley, Jacob T., E-mail: shellj@rpi.edu [Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242 (United States); Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY, 12180 (United States)

    2017-01-15

    An atmospheric-pressure solution-cathode glow discharge (SCGD) has been evaluated as an ion source for atomic, molecular, and ambient desorption/ionization mass spectrometry. The SCGD consists of a direct-current plasma, supported in the ambient air in the absence of gas flows, and sustained upon the surface of a flowing liquid cathode. Analytes introduced in the flowing liquid, as an ambient gas, or as a solid held near the plasma are vaporized and ionized by interactions within or near the discharge. Introduction of acidic solutions containing metal salts produced bare elemental ions as well as H{sub 2}O, OH{sup −} and NO{sub 3}{sup −} adducts. Detection limits for these elemental species ranged from 0.1 to 4 ppb, working curves spanned more than 4 orders of linear dynamic range, and precision varied between 5 and 16% relative standard deviation. Small organic molecules were also efficiently ionized from solution, and both the intact molecular ion and fragments were observed in the resulting SCGD mass spectra. Fragmentation of molecular species was found to be tunable; high discharge currents led to harder ionization, while low discharge currents produced stronger molecular-ion signals. Ambient gases and solids, desorbed by the plasma from a glass probe, were also readily ionized by the SCGD. Indeed, strong analyte signals were obtained from solid samples placed at least 2 cm from the plasma. These findings indicate that the SCGD might be useful also for ambient desorption/ionization mass spectrometry. Combined with earlier results that showed the SCGD is useful for ionization of labile biomolecules, the results here indicate that the SCGD is a highly versatile ion source capable of providing both elemental and molecular mass-spectral information. - Highlights: • Solution-cathode glow discharge used as an ionization source for mass spectrometry. • SCGD-MS can provide atomic as well as intact molecular mass spectra. • Atomic limits of detection range

  10. AGING EFFECTS OF REPEATEDLY GLOW-DISCHARGED POLYETHYLENE - INFLUENCE ON CONTACT-ANGLE, INFRARED-ABSORPTION, ELEMENTAL SURFACE-COMPOSITION, AND SURFACE-TOPOGRAPHY

    NARCIS (Netherlands)

    VANDERMEI, HC; STOKROOS, [No Value; SCHAKENRAAD, JM; BUSSCHER, HJ

    1991-01-01

    Aging effects of repeatedly oxygen glow-discharged polyethylene surfaces were determined by water contact angle measurements, infrared (IR) spectroscopy, X-ray photoelectron (XPS) spectroscopy, and surface topography determination. Glow-discharged surfaces were stored at room temperature and in

  11. Discharge transitions between glow-like and filamentary in a xenon/chlorine-filled barrier discharge lamp

    Energy Technology Data Exchange (ETDEWEB)

    Xu Jinzhou; Guo Ying; Xia Lei; Zhang Jing [Department of Applied Physics, Plasma and Application Research Center, DongHua University, Shanghai 201620 (China)

    2007-08-15

    An asymmetric electric voltage pulse source (2-20 kHz, V{sub p-p}: 0-20 kV) was applied to stimulate excimer radiation by a dielectric barrier discharge in a binary gas mixture of chlorine (10.8 Torr)/xenon at high pressure ({approx}460 Torr). When the source frequency increases continuously from 2.0 to 12.0 kHz or in reverse under a fixed output voltage of V{sub p-p} (13.8 kV), it is observed that the discharge modes excited by this pulse source transmit between glow-like and filamentary, and we observe a mixed mode with filaments randomly distributed in the diffuse-like background in the narrow frequency range 7.0-8.0 kHz. It is argued that the reasons for the discharge transition could be the frequency and the time derivative of the voltage waveform of the power source. It is also observed that there is an obvious difference in the emission spectral profiles and the energy efficiency of excimer emission for the two discharge modes.

  12. Hybrid modelling of open glow discharge with account of nonlocal ionization by fast electrons

    Science.gov (United States)

    Eliseev, Stepan; Eremin, Denis; Kudryavtsev, Anatoly

    2015-11-01

    Cage and open discharges as well as hollow cathode devices are used for creating negative glow plasma. In order to perform numerical simulations of such kind of plasma object properly it is necessary to account for nonlocal excitation and ionization induced by fast electrons emitted from cathode and accelerated up to energies 102-103eV in cathode voltage drop. In this work a numerical study of open discharge in argon is presented. Simulations were performed using simple hybrid model that incorporates nonlocal ionization by fast electrons into ``extended'' fluid framework. Electron energy balance is written with account of electron heating due to coulomb interaction between ``bulks'' (with energies less than 1eV) and ``intermediate'' electrons (with energies up to inelastic collisions energy threshold). Distributions of main discharge parameters, such charged particle densities, electron temperature, electric potential, current-voltage characteristics of the discharge were obtained. Comparison with experimental results showed good agreement and suggests good applicability of the model. This work was supported by Russian Science Foundation (project #14-19-00311).

  13. Turbulence Induced Distortion of Resonance Absorption in a Glow Discharge Tube's Plasma*

    Science.gov (United States)

    Johnson, J. A., III; Roberson, Stephen; Williams, Kyron; Appartaim, Richard

    1999-11-01

    The glow discharge tube provides a reliable turbulent plasma over a range of turbulent states with densities comparable to the tokamak divertor regions. The fully turbulent plasma state can be manipulated through changes in the tube's pressure and the tube's operating current. A pulsed OPO laser at 488.0nm excites Ar ions in the plasma which in turn provide resonant radiation at 422.7nm. We observe changes in the lifetime of the excited state which are correlated with changes in the nature of the local turbulence and changes in a superposed local magnetic field. These changes are interpreted using quantum mechanical enhancements of a modified kinetic theory. The results are applied to potential stability issues in the design of fusion power plants.

  14. Control of discharge conditions to reduce hydrogen content in low Z films produced with DC glow

    Energy Technology Data Exchange (ETDEWEB)

    Natsir, M.; Sagara, A.; Tsuzuki, K.; Tsuchiya, B.; Hasegawa, Y.; Motojima, O.

    1995-09-01

    Boronization at near room temperature has been performed in plasma processing teststand (PPT) by using a 5 % diborane gases B{sub 2}H{sub 6} in He on electrically floating or unfloating Al samples under various conditions on DC glow discharge power or total gas pressure. The hydrogen concentration was analyzed by using elastic recoil detection method (ERD) and a new modified normalizing technique with Rutherford back scattering (RBS). Results showed that a high growth rate of film formation and floating surface were effective in reducing hydrogen concentration in B films. This result was in good agreement with earlier measurements of H with flash filament (FF) desorption method. In particular the H/B ratio was reduced by decreasing ions but increasing radicals for B film formation. (author).

  15. Direct Current Magnetron Glow Discharge Plasma Characteristics Study for Controlled Deposition of Titanium Nitride Thin Film

    Directory of Open Access Journals (Sweden)

    Sankar Moni Borah

    2013-01-01

    Full Text Available This paper reports on the study of direct current (DC magnetron glow discharge plasma characteristics in a cylindrical magnetron system in argon-nitrogen. Presence of nitrogen gas makes the plasma environment reactive, and it results in significant changes of the plasma properties—number density, electron temperature, floating potential, and sheath thickness. Applied magnetic field is a parameter which is closely related to proper deposition of thin film. Cylindrical Langmuir probe and Emissive probe are used as diagnostics for the estimation of various plasma parameters indicated earlier. Controlled titanium nitride (TiN thin film deposition on bell-metal at different argon-nitrogen gases ratio is another important study reported.

  16. Hydrogen in carbon foils made by DC glow discharge in ethylene

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, P.; Armour, D.G. (Salford Univ. (UK). Dept. of Electrical Engineering); England, J.B.A. (Birmingham Univ. (UK). Dept. of Physics); Tait, N.R.S.; Tolfree, D.W.L. (Science and Engineering Research Council, Daresbury (UK). Daresbury Lab.)

    1983-08-01

    Thermal desorption has been studied from thin films of carbon prepared by dc glow discharge in ethylene. The only gases released in significant quantities are hydrogen and methane. Both releases can be characterised by a continuum of activation energies but the methane release peaks at a lower temperature than that from hydrogen. The estimated total hydrogen release is compared with the hydrogen content determined by nuclear scattering experiments. Infrared studies suggest that the majority of CH/sub 2/ and CH/sub 3/ bonds can be ruptured by annealing at 300/sup 0/C, a temperature well below the hydrogen and methane release rate maxima. Possible hydrogen bonding modes and desorption mechanisms are discussed.

  17. Effects of the ion-solid interaction in glow discharge vapour deposition polymerization of pyromellitic dianhydride

    Energy Technology Data Exchange (ETDEWEB)

    Maggioni, G. E-mail: maggioni@inl.infn.it; Carturan, S.; Rigato, V.; Pieri, U

    2000-05-02

    Low energy He ion bombardment of pyromellitic dianhydride monomer used in glow discharge vapour deposition polymerization (GDVDP) of polyimide coatings and its effects on the film deposition process have been studied. The sublimation of the monomer molecules and the simultaneous formation of a damaged, carbon-rich surface layer on the target are discussed from a theoretical point of view based on simulations of the ion-solid interaction. Optical emission and mass spectrometry have been used to analyse the species emitted from the target. In order to study the time evolution of the PMDA target damage, the deposition rate of monomer molecules has been monitored. FT-IR spectroscopy has been used to determine the molecular damaging of the target monomer and deposited films.

  18. Effect of glow discharge sintering in the properties of a composite material fabricated by powder metallurgy

    Science.gov (United States)

    Cardenas, A.; Pineda, Y.; Sarmiento Santos, A.; Vera, E.

    2016-02-01

    Composite samples of 316 stainless steel and SiC were produced by powder metallurgy. Starting materials were mixed in different proportions and compacted to 700MPa. Sintering stage was performed by abnormal glow discharge plasma with direct current in an inert atmosphere of argon. The process was conducted at a temperature of 1200°C±5°C with a heating rate of 100°C/min. This work shows, the effectiveness of plasma sintering process to generate the first contacts between particles and to reduce vacancies. This fact is confirmed by comparing green and sintered density of the material. The results of porosity show a decrease after plasma sintering. Wear tests showed the wear mechanisms, noting that at higher SiC contents, the wear resistance decreases due to poor matrix-reinforcement interaction and by the porosity presence which causes matrix-reinforcement sliding.

  19. Heterodyne detection at 300 GHz using neon indicator lamp glow discharge detector.

    Science.gov (United States)

    Aharon Akram, Avihai; Rozban, Daniel; Kopeika, Natan S; Abramovich, Amir

    2013-06-10

    A miniature neon indicator lamp, also known as a glow discharge detector (GDD), costing about 50 cents, was found to be an excellent room temperature terahertz radiation detector. Proof-of-concept 300 GHz heterodyne detection using GDD is demonstrated in this paper. Furthermore, a comparison to direct detection was carried out as well. Previous results with the GDD at 10 GHz showed 40 times better sensitivity using heterodyne detection compared to direct detection. Preliminary results at 300 GHz showed better sensitivity by a factor of 20 with only 56 μW local-oscillator power using heterodyne compared to direct detection. The higher the local-oscillator power (P(lo)), the better the sensitivity of the detector. Further improvement can be achieved by employing better quasi-optical design.

  20. Nonlinear time-series analysis of current signal in cathodic contact glow discharge electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Allagui, Anis, E-mail: aallagui@sharjah.ac.ae; Abdelkareem, Mohammad Ali [Department of Sustainable and Renewable Energy Engineering, University of Sharjah, PO Box 27272, Sharjah (United Arab Emirates); Rojas, Andrea Espinel [Institut de Recherche en Communications et Cybernétique de Nantes, Ecole Centrale de Nantes, 44300 Nantes (France); Bonny, Talal; Elwakil, Ahmed S. [Department of Electrical and Computer Engineering, University of Sharjah, PO Box 27272, Sharjah (United Arab Emirates)

    2016-05-28

    In the standard two-electrode configuration employed in electrolytic process, when the control dc voltage is brought to a critical value, the system undergoes a transition from conventional electrolysis to contact glow discharge electrolysis (CGDE), which has also been referred to as liquid-submerged micro-plasma, glow discharge plasma electrolysis, electrode effect, electrolytic plasma, etc. The light-emitting process is associated with the development of an irregular and erratic current time-series which has been arbitrarily labelled as “random,” and thus dissuaded further research in this direction. Here, we examine the current time-series signals measured in cathodic CGDE configuration in a concentrated KOH solution at different dc bias voltages greater than the critical voltage. We show that the signals are, in fact, not random according to the NIST SP. 800-22 test suite definition. We also demonstrate that post-processing low-pass filtered sequences requires less time than the native as-measured sequences, suggesting a superposition of low frequency chaotic fluctuations and high frequency behaviors (which may be produced by more than one possible source of entropy). Using an array of nonlinear time-series analyses for dynamical systems, i.e., the computation of largest Lyapunov exponents and correlation dimensions, and re-construction of phase portraits, we found that low-pass filtered datasets undergo a transition from quasi-periodic to chaotic to quasi-hyper-chaotic behavior, and back again to chaos when the voltage controlling-parameter is increased. The high frequency part of the signals is discussed in terms of highly nonlinear turbulent motion developed around the working electrode.

  1. Positive column of a glow discharge in neon with charged dust grains (a review)

    Science.gov (United States)

    Polyakov, D. N.; Shumova, V. V.; Vasilyak, L. M.

    2017-03-01

    The effect of charged micron-size dust grains (microparticles) on the electric parameters of the positive column of a low-pressure dc glow discharge in neon has been studied experimentally and numerically. Numerical analysis is carried out in the diffusion-drift approximation with allowance for the interaction of dust grains with metastable neon atoms. In a discharge with a dust grain cloud, the longitudinal electric field increases. As the number density of dust grains in an axisymmetric cylindrical dust cloud rises, the growth of the electric field saturates. It is shown that the contribution of metastable atoms to ionization is higher in a discharge with dust grains, in spite of the quenching of metastable atoms on dust grains. The processes of charging of dust grains and the dust cloud are considered. As the number density of dust grains rises, their charge decreases, while the space charge of the dust cloud increases. The results obtained can be used in plasma technologies involving microparticles.

  2. Optical investigations of high pressure glow discharges based on MSE arrays

    Energy Technology Data Exchange (ETDEWEB)

    Penache, C.; Hohn, O.; Schmidt-Boecking, H. [Frankfurt Univ. (Germany); Spielberger, L. [Deutsche Gesellschaft fuer Technische Zusammenarbeit GmbH (GTZ), Eschborn (Germany); Braeuning-Demian, A.; Penache, D. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)

    2001-07-01

    The micro-structure-electrode (MSE) arrays are providing a non-thermal high pressure plasma. These arrays consist of a matrix of holes perforated in a thin multilayer made out of two metallic foils separated by a dielectric. The holes diameter and the thickness of the insulator spacer need to be around 100 {mu}m to allow for the MSE operation at pressure ranging from 0.1 to 1 bar and above. In this work single direct current microdischarges and systems of parallel operated holes in argon at 0.2 bar have been optically investigated. The spatial distribution of the emitted light has been monitored by a digital camera connected to an optical microscope. The UV photon emission has been recorded by a position sensitive photon detector allowing for space and time resolved measurements. Its time resolution of about 1 nsec makes possible the investigation of fast processes, e.g. the constriction of the discharge. Due to its typical position resolution of 100 {mu}m, this detector needs to be used in combination with an optical system allowing for the magnification of the discharge area. The optical appearance show a stable, volume filling glow discharge, fact proved also by the typical current-voltage characteristic.

  3. Positive column of a glow discharge in neon with charged dust grains (a review)

    Energy Technology Data Exchange (ETDEWEB)

    Polyakov, D. N., E-mail: cryolab@ihed.ras.ru; Shumova, V. V.; Vasilyak, L. M. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2017-03-15

    The effect of charged micron-size dust grains (microparticles) on the electric parameters of the positive column of a low-pressure dc glow discharge in neon has been studied experimentally and numerically. Numerical analysis is carried out in the diffusion-drift approximation with allowance for the interaction of dust grains with metastable neon atoms. In a discharge with a dust grain cloud, the longitudinal electric field increases. As the number density of dust grains in an axisymmetric cylindrical dust cloud rises, the growth of the electric field saturates. It is shown that the contribution of metastable atoms to ionization is higher in a discharge with dust grains, in spite of the quenching of metastable atoms on dust grains. The processes of charging of dust grains and the dust cloud are considered. As the number density of dust grains rises, their charge decreases, while the space charge of the dust cloud increases. The results obtained can be used in plasma technologies involving microparticles.

  4. Study of generating nitrogen plasma jet by using glow discharge in non-uniform gap

    Science.gov (United States)

    Liu, Wenzheng; Li, Zhiyi; Ma, Chuanlong; Zhao, Luxiang

    2017-10-01

    Experimental studies of a larger-scale atmospheric pressure glow discharge (APGD) nitrogen plasma jet are presented in this paper. A chamber with non-uniform gap formed in the electrode structure is designed by using non-uniform thickness of dielectrics. Through the electric field simulation, it is found that there is a non-uniform electric field distribution in the lateral and longitudinal directions of the chamber. The discharge starts from the larger electric field intensity of the submillimeter and then is followed by the development to the left and right sides of the smaller electric field intensity of the long gap. Moreover, the non-uniform electric field distribution in the lateral and longitudinal directions can help to suppress the generation of filament discharge. The experiments indicate that a uniform APGD in nitrogen is formed in the chamber and the inner electrode surface has a large luminous intensity. Through the fluid simulation, it is found that the velocity of the gas at the inner electrode surface is large. As a result, the nitrogen flow can effectively bring out the high-density plasmas on the inner electrode surface, which is beneficial to the formation of the plasma jet. The experimental results show that the electrode structure can generate APGD nitrogen plasma jets with the length of 10 mm and width of 15 mm, which is of relatively high application value.

  5. Time evolution of vibrational temperatures in a CO2 glow discharge measured with infrared absorption spectroscopy

    Science.gov (United States)

    Klarenaar, B. L. M.; Engeln, R.; van den Bekerom, D. C. M.; van de Sanden, M. C. M.; Morillo-Candas, A. S.; Guaitella, O.

    2017-11-01

    Vibrational temperatures of CO2 are studied in a pulsed glow discharge by means of time-resolved in situ Fourier transform infrared spectroscopy, with a 10 μs temporal resolution. A method to analyze the infrared transmittance through vibrationally excited CO2 is presented and validated on a previously published CO2 spectrum, showing good agreement between fit and data. The discharge under study is pulsed with a typical duty cycle of 5–10 ms on–off, at 50 mA and 6.7 mbar. A rapid increase of the temperature of the asymmetric stretch vibration (T 3) is observed at the start of the pulse, reaching 1050 K, which is an elevation of 550 K above the rotational temperature ({T}{{rot}}) of 500 K. After the plasma pulse, the characteristic relaxation time of T 3 to {T}{{rot}} strongly depends on the rotational temperature. By adjusting the duty cycle, the rotational temperature directly after the discharge is varied from 530 to 860 K, resulting in relaxation times between 0.4 and 0.1 ms. Equivalently, as the gas heats up during the plasma pulse, the elevation of T 3 above {T}{{rot}} decreases strongly.

  6. Global Modeling of N2O Discharges: Rate Coefficients and Comparison with ICP and Glow Discharges Results

    Directory of Open Access Journals (Sweden)

    Konstantinos Katsonis

    2013-01-01

    Full Text Available We developed a Global Model for N2O plasmas valid for applications in various power, gas flow rate, and pressure regimes. Besides energy losses from electron collisions with N2O, it takes into consideration those due to molecular N2 and O2 and to atomic N and O species. Positive atomic N+ and O+ and molecular N2O+, N2+, and O2+ have been treated as separate species and also negative O− ions. The latter confer an electronegative character to the discharge, calling for modified plasma sheath and plasma potential formulas. Electron density and temperature and all species densities have been evaluated, hence the ionization and dissociation percentages of N2O, N2, and O2 molecules and the plasma electronegativity. The model is extended to deal with N2/O2 mixtures feedings, notably with air. Rate coefficients and model results are discussed and compared with those from available theoretical and experimental work on ICP and glow discharge devices.

  7. Glow discharge plasma in water: a green approach to enhancing ability of chitosan for dye removal.

    Science.gov (United States)

    Wen, Yuezhong; Shen, Chensi; Ni, Yanyan; Tong, Shaoping; Yu, Feng

    2012-01-30

    There is a need to explore effective and green approaches to enhancing the ability to use chitosan for contaminant removal for practical implementation of this technology. In the present study, glow discharge plasma (GDP), which has thus far been studied for degradation of contaminants, was used for the first time to pre-treat chitosan for dye removal in aqueous solution. The results show that the GDP treatment changed the morphology and crystallinity of chitosan particles, and the number of -CH(2) and -CH(3) groups in the chitosan samples increased. Various pretreatment parameters, including discharge current and time, played significant roles in the chitosan modification. It is observed that dye uptake in GDP-modified chitosan was faster than adsorption in untreated chitosan. The maximum adsorption by chitosan followed the order of untreated chitosanGDP current: 50 mA)GDP current: 120 mA), implying that the chitosan modified by GDP had a higher maximum adsorption capacity in comparison with the untreated chitosan. A possible mechanism is proposed. These results show that GDP may be an attractive pretreatment technology for environmental adsorption materials. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Control of plasma properties in a short direct-current glow discharge with active boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Adams, S. F. [Air Force Research Laboratory, WPAFB, Ohio 45433 (United States); Demidov, V. I., E-mail: vladimir.demidov@mail.wvu.edu [Air Force Research Laboratory, WPAFB, Ohio 45433 (United States); West Virginia University, Morgantown, West Virginia 26506 (United States); Bogdanov, E. A.; Kudryavtsev, A. A. [St. Petersburg State University, St. Petersburg 199034 (Russian Federation); Koepke, M. E. [West Virginia University, Morgantown, West Virginia 26506 (United States); Kurlyandskaya, I. P. [St. Petersburg University of State Fire Service of EMERCOM RF, Murmansk Branch, Murmansk 183040 (Russian Federation)

    2016-02-15

    To demonstrate controlling electron/metastable density ratio and electron temperature by applying negative voltages to the active (conducting) discharge wall in a low-pressure plasma with nonlocal electron energy distribution function, modeling has been performed in a short (lacking the positive-column region) direct-current glow discharge with a cold cathode. The applied negative voltage can modify the trapping of the low-energy part of the energetic electrons that are emitted from the cathode sheath and that arise from the atomic and molecular processes in the plasma within the device volume. These electrons are responsible for heating the slow, thermal electrons, while production of slow electrons (ions) and metastable atoms is mostly due to the energetic electrons with higher energies. Increasing electron temperature results in increasing decay rate of slow, thermal electrons (ions), while decay rate of metastable atoms and production rates of slow electrons (ions) and metastable atoms practically are unchanged. The result is in the variation of electron/metastable density ratio and electron temperature with the variation of the wall negative voltage.

  9. Atmospheric Pressure Glow Discharge for Point-of-Use Water Treatment

    Science.gov (United States)

    Lindsay, Alexander; Byrns, Brandon; Shannon, Steven; Knappe, Detlef

    2012-10-01

    Treatment of biological and chemical contaminants is an area of growing global interest where atmospheric pressure plasmas can make a significant contribution. Addressing key challenges of volume processing and operational cost, a large volume 162 MHz coaxial air-plasma source has been developed.footnotetextByrns (2012) J. Phys. D: Appl. Phys. 45 (2012) 195204 Because of VHF ballasting effects, the electric discharge is maintained at a steady glow, allowing formation of critical non-equilibrium chemistry. High densities, ne = 10^11-10^12, have been recorded. The atmospheric nature of the device permits straightforward and efficient treatment of water samples. [H^+] concentrations in 150 milliliter tap water samples have been shown to increase by 10^5 after five minutes of discharge exposure. Recent literature has demonstrated that increasing acidity is strongly correlated with a solution's ability to deactivate microbial contaminants.footnotetextTraylor (2011) J. Phys. D: Appl. Phys. 44 (2011) 472001 The work presented here will explore the impact of treatment gas, system configuration, and power density on water disinfection and PFC abatement. An array of plasma diagnostics, including OES and electrical measurements, are combined with post-process water analysis, including GC-MS and QT analysis of coliform and E.coli bacteria. Development of volume processing atmospheric plasma disinfection methods offers promise for point-of-use treatments in developing areas of the world, potentially supplementing or replacing supply and weather-dependent disinfection methods.

  10. Investigation of the transition between glow and streamer discharges in atmospheric air

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jai Hyuk [Department of Metallurgical Engineering, Yonsei University, Seodaemoon-Ku, Shinchon-Dong 134, Seoul 120-749 (Korea, Republic of); Lee, Tae Il [Department of Metallurgical Engineering, Yonsei University, Seodaemoon-Ku, Shinchon-Dong 134, Seoul 120-749 (Korea, Republic of); Han, Inho [Department of Metallurgical Engineering, Yonsei University, Seodaemoon-Ku, Shinchon-Dong 134, Seoul 120-749 (Korea, Republic of); Baik, Hong Koo [Department of Metallurgical Engineering, Yonsei University, Seodaemoon-Ku, Shinchon-Dong 134, Seoul 120-749 (Korea, Republic of); Song, Kie Moon [Department of Applied Physics, KonKuk University, Chungju 380-701 (Korea, Republic of); Lim, Yong Sik [Department of Applied Physics, KonKuk University, Chungju 380-701 (Korea, Republic of); Lee, Eung Suok [Advanced Technology Team, Samsung Electro-Mechanics Co Ltd, Suwon, 442-743 (Korea, Republic of)

    2006-08-15

    Generally, the parameter p {center_dot} d (pressure x gap distance) in dielectric barrier discharge (DBD) controls the electrical breakdown and also the plasma characteristics. We investigated the optimum plasma transition p {center_dot} d by controlling the pressure. To find the transition p {center_dot} d (p {center_dot} d{sub tr}) condition, optical emission spectroscopy (OES) was used to measure emission spectra from the DBD. All p {center_dot} d data were normalized by the second positive system of nitrogen molecules, the wavelength of which was 337.1 nm. Then we compared the relative intensities of species generated during the discharge by OES analysis. Species selected for comparison were the first negative system (FNS) of nitrogen molecules (391.4 nm) and atomic oxygen spectra (777.1 nm). Experimental results showed that relative intensities were almost constant as p {center_dot} d decreased, but at specific p {center_dot} d data, the intensity started to increase. The increase in FNS of nitrogen molecules means not only an increase in electron energy but also a change in the plasma mode, streamer to glow transition. In the case of DBD using alumina with 1 mm thickness applied ac power, the plasma transition occurred at the 1 Torr cm condition.

  11. Design and characterization of a direct current glow discharge lamp for analytical applications

    Energy Technology Data Exchange (ETDEWEB)

    Dimri, A.K. [Central Scientific Instruments Organisation, Sector-30, Chandigarh 160030 (India)]. E-mail: akrdimri@yahoo.com; Paul, A.K. [Central Scientific Instruments Organisation, Sector-30, Chandigarh 160030 (India); Bajpai, R.P. [Central Scientific Instruments Organisation, Sector-30, Chandigarh 160030 (India)

    2004-11-08

    This paper describes a compact, small volume direct current glow discharge lamp operating at low wattage for atomic emission spectrometric analysis and its process optimization for copper and brass solid samples. The design aspects, fundamental characteristics and analytical performance are described in detail. The discharge is observed end-on, with water-cooled cathode surface parallel to the spectroscopic entrance slit. The anode diameter is 7 mm and the minimum sample diameter required is 20 mm. The sample is located outside the lamp for easy access and interchangeability. The lamp is powered by a dc power supply capable of delivering 300 mA (max.) and 1500 V. The studies of fundamental characteristics include the current-voltage relationship and their dependence on pressure and the emission intensity of copper spectral line (324.7 nm). The studies were made in the pressure range of 2-7 mbar. Long-term stability of optical emission spectra was also recorded to be within {+-}0.75%. The performance of the lamp is quite linear in the pressure range 3.5-7 mbar at an applied voltage of about 450 V.

  12. Aspects of the practical application of titanium alloys after low temperature nitriding glow discharge in hydrogen- free -gas media

    Energy Technology Data Exchange (ETDEWEB)

    Mashovets, N.S., E-mail: mashovets@rambler.ru [Khmelnickiy National University (Ukraine); Pastukh, I.M., E-mail: pastim@mail.ru [Khmelnickiy National University (Ukraine); Voloshko, S.M. [Khmelnickiy National University (Ukraine); National Technical University of Ukraine “Kyiv Polytechnic Institute” (Ukraine)

    2017-01-15

    Highlights: • Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. • Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). • The above material shows the promise of the technology of low-temperature hydrogen-nitriding by glow discharge. This greatly expands the range of practical applications of titanium alloys. - Abstract: X-ray diffraction analysis, X-ray photoelectron spectroscopy, and Electron Auger-spectroscopy investigation of phase transformation on the surface of the VT8 titanium alloy after a low temperature hydrogen-free nitriding in a glow discharge. Operational characteristics of titanium alloys defined physical-mechanical characteristics of the surface and their phase composition, which depend on the process parameters of nitriding. Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. The main advantage of this method lies in the absence of hydrogen embrittlement and complete environmental safety process. Application of the glow discharge can not only speed up the process by the order of the diffusion surface saturation with nitrogen, but also significantly alters the kinetics of the process and quality of the nitrided layer, in particular its physio-mechanical properties and phase composition. For research purposes, the standards from an α + β alloy Ti-Al6-Cr2-Mo2,5 (VT8) were used. Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Stratified analysis by AES was conducted by etching the surface of the samples’ argon ion beam with diameters of 1.5 mm with an energy of 3000 eV and a current density of 400 mA/cm{sup 2}. The above material shows the promise of the technology of low

  13. Variation of Lap Shear Tensile Strength of Polycarbonate Mild Steel Adhesive Joints with DC Glow Discharge Modified Polycarbonate

    Science.gov (United States)

    Panwar, Amrish K.; Barthwal, S. K.; Ray, S.

    2007-01-01

    It has been observed that the wettability/surface energy of polycarbonate (PC) changes with the variation in process parameters, such as discharge power and time of exposure of DC glow discharge. The wettability of the PC surface has been measured by the contact angle measurements of two test liquids, such as water and formamide, by the sessile drop method. The lap shear tensile strength (LSTS) of PC to the mild steel (MS) adhesive joint has been measured with both the as-received polymer and those exposed under DC glow discharge. An appreciable increase in the LSTS has been attained for samples treated under DC glow discharge at a lower power level and also at a short exposure time at higher power. This increase in LSTS is attributed to increased polar surface energy with increasing power and time of exposure. After a certain level of surface modification of the PC, the strength of the adhesive joint deteriorates, while the total surface energy and its polar component may increase continuously. The subsurface damage taking place particularly at long exposure times and at higher power may lead to deterioration of LSTS in spite of a strong interface between the polymer and the adhesive. In such a case, the joint is observed to fracture not across the interface but through the subsurface. The optimum exposure limits the subsurface damage while creating a strong interface.

  14. Composite state control and magnetic properties of Co and Si cluster assemblies prepared with double-glow-discharge sources

    Science.gov (United States)

    Katoh, Ryoji; Hihara, Takehiko; Peng, Dong-Liang; Sumiyama, Kenji

    2006-08-01

    Using a double-glow-discharge-cluster-source system, in which one glow discharge was a dc mode and the other an rf discharge mode, Co and Si clusters were independently produced and simultaneously deposited on a substrate. When a separation plate was inserted between two glow-discharge chambers, a mixture of Co and Si clusters was obtained: small Co clusters were distributed at random, while the Si clusters were aggregated to form large secondary particles. Without inserting the separation plate, on the other hand, core-shell clusters were obtained: a Co core was surrounded by small Si crystallites. The magnetization measurement indicated that the magnetic coercive force of Co /Si core-shell cluster assemblies was much smaller than that of Co cluster assemblies in which Co clusters were covered with antiferromagnetic CoO shells, indicating that the Si shell prevented Co cluster surfaces from their oxidation. Therefore, the present double-cluster-source system is useful in fabricating various sorts of cluster composites, which cannot be prepared by conventional coevaporation or precipitation methods.

  15. Sustained diffusive alternating current gliding arc discharge in atmospheric pressure air

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Li, Zhongshan

    2014-01-01

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

  16. Enhancing DC Glow Discharge Tube Museuum Displays using a Theremin Controlled Helmholtz Coil to Demonstrate Magnetic Confinement

    Science.gov (United States)

    Siu, Theodore; Wissel, Stephanie; Guttadora, Larry; Liao, Susan; Zwicker, Andrew

    2010-11-01

    Since their discovery in the mid 1800's, DC glow discharge apparatuses have commonly been used for spectral analysis, the demonstration of the Frank-Hertz experiment, and to study plasma breakdown voltages following from the Paschen Curve. A DC glow discharge tube museum display was outfitted with a Helmholtz Coil electromagnet in order to demonstrate magnetic confinement for a science museum display. A device commonly known as a ``theremin'' was designed and built in order to externally control the Helmholtz Coil current and the plasma current. Originally a musical instrument, a theremin has two variable capacitors connected to two radio frequency oscillators which determine pitch and volume. Using a theremin to control current and ``play'' the plasma adds appeal and durability by providing a new innovative means of interacting with a museum exhibit. Educationally, students can use the display to not only learn about plasma properties but also electronic properties of the human body.

  17. Order–chaos–order–chaos transition and evolution of multiple anodic double layers in glow discharge plasma

    Directory of Open Access Journals (Sweden)

    Prince Alex

    2015-01-01

    Full Text Available Plasma often shows complex dynamic behavior. We present an experimental observation of order–chaos–order–chaos transition in glow discharge plasma. These transitions correspond to the evolution of different stages of a multiple anodic double layer. Multiple anodic double layers were produced in a typical glow discharge condition and associated floating potential oscillations were recorded for monotonous variation of one of the control parameters i.e. the cathode voltage. With a variation in the cathode voltage, the multiple anodic double layers were evolved to different stages. The recorded experimental time series data had been analyzed and quantified using power spectra, phase space trajectories, time-delay reconstructions of state space, Lyapunov exponent and correlation dimensions. The analysis shows that the chaotic behavior corresponds to diffused boundaries between two double layers.

  18. Destruction of 4-phenolsulfonic acid in water by anodic contact glow discharge electrolysis.

    Science.gov (United States)

    Yang, Haiming; An, Baigang; Wang, Shaoyan; Li, Lixiang; Jin, Wenjie; Li, Lihua

    2013-06-01

    Destruction of 4-phenolsulfonic acid (4-PSA) in water was carried out using anodic contact glow discharge electrolysis. Accompanying the decay of 4-PSA, the amount of total organic carbon (TOC) in water correspondingly decreased, while the sulfonate group of 4-PSA was released as sulfate ion. Oxalate and formate were obtained as minor by-products. Additionally, phenol, 1,4-hydroquinone, hydroxyquinol and 1,4-benzoquinone were detected as primary intermediates in the initial stages of decomposition of 4-PSA. A reaction pathway involving successive attacks of hydroxyl and hydrogen radicals was assumed on the basis of the observed products and kinetics. It was revealed that the decay of both 4-PSA and TOC obeyed a first-order rate law. The effects of different Fe ions and initial concentrations of 4-PSA on the degradation rate were investigated. It was found that the presence of Fe ions could increase the degradation rate of 4-PSA, while initial concentrations lower than 80 mmol/L had no significant effect on kinetic behaviour. The disappearance rate of 4-PSA was significantly affected by pH.

  19. Surface Modification of Asymmetric Polysulfone/Polyethylene Glycol Membranes by DC Ar-Glow Discharge Plasma

    Directory of Open Access Journals (Sweden)

    Chalad Yuenyao

    2016-01-01

    Full Text Available Polysulfone/polyethylene glycol (PSF/PEG membranes were prepared by dry/wet phase inversion method. Effects of direct current glow discharge plasma using argon as working gas on morphological structures and gas separation properties of membranes were studied. Alteration of membrane characteristics were analyzed by various techniques like contact angle, scanning electron microscope, Fourier transform infrared spectroscopy, and dynamic mechanical thermal analysis. Gas separation properties were measured in terms of permeation and ideal O2/N2 selectivity. Results showed that hydrophilic and gas separation properties of PSF/PEG membranes increased by plasma surface modification. It was also shown that the dosage of PEG and plasma treatment affected the morphological structures and mechanical and gas separation properties. The macro voids and transmembrane structure disappeared with a little amount of PEG dosage. Pore size and mechanical strength tend to decrease with increasing PEG dosage up to 10 wt%. Glass transition temperature (Tg receded from 201.8 to 143.7°C for pure PSF and PSF/PEG with PEG dosage of 10 wt%. O2 and N2 gases permeation through the 10-minute plasma treated membranes tend to increase. However, the permeation strongly dispersed when treatment time was more extended.

  20. Dechlorination and decomposition of chloroform induced by glow discharge plasma in an aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yongjun, E-mail: lyjglow@sohu.com [College of Environmental Science & Engineering, Dalian Maritime University, Dalian 116026 (China); Brook Byers Institute for Sustainable Systems, Georgia Institute of Technology, Atlanta 30332 (United States); Crittenden, John C. [Brook Byers Institute for Sustainable Systems, Georgia Institute of Technology, Atlanta 30332 (United States); Wang, Lei [College of Environmental Science & Engineering, Xiamen University of Technology, Xiamen 361024 (China); Liu, Panliang [Brook Byers Institute for Sustainable Systems, Georgia Institute of Technology, Atlanta 30332 (United States)

    2016-05-05

    Highlights: • Hydrated electrons played an important role for chloroform decomposition. • Oxygen enhanced hydrolyses are critical for the chloroform mineralization. • Energy efficiency of GDP is higher than those of the typical competitive processes. - Abstract: In this study, efficient dechlorination and decomposition of chloroform (CF) induced by glow discharge plasma (GDP) in contact with a sodium sulfate solution was investigated. Intermediate byproducts were determined by ionic chromatography and headspace gas chromatography, respectively. Results showed that CF can be effectively dechlorinated and decomposed under the action of GDP. Both removal and dechlorination of CF increased with increasing pH and with addition of hydroxyl radical scavengers to the solution. Addition of H{sub 2}O{sub 2} to the solution slightly decreased the CF removal. Formic acid, oxalic acid and dichloromethane were determined as the major intermediate byproducts. Final products were carbon dioxide and hydrochloric acid. Hydrated electrons were the most likely active species responsible for initiation of the dechlorination, and hydroxyl radicals may be the ones for the oxidation of the organic intermediate byproducts. Hydrolyses of the chloromethyl radicals contributed much in the mineralization of the organic chlorine. Reaction mechanism was proposed based on the dechlorination kinetics and the distribution of intermediate byproducts.

  1. Investigation of multifractal nature of floating potential fluctuations obtained from a dc glow discharge magnetized plasma

    Science.gov (United States)

    Shaw, Pankaj Kumar; Saha, Debajyoti; Ghosh, Sabuj; Janaki, M. S.; Iyengar, A. N. Sekar

    2017-03-01

    In this paper, multifractal detrended fluctuation analysis (MF-DFA) has been used to analyze the floating potential fluctuations obtained with a Langmuir probe from a dc glow discharge magnetized plasma device. The generalized Hurst exponents (h(q)) , local fluctuation function (Fq(s)) , the Rényi exponents (τ(q)) and the multifractal spectrum F(α) have been calculated by applying the MF-DFA method. The result of the MF-DFA shows the multifractal nature of these fluctuations. We have investigated the influence of magnetic field on the multifractal nature of the fluctuations and it is seen that degree of multifractality is reduced with the increase in the magnetic field strength. The values of h(q) have been restricted between 0.7 and 1 for the magnetized fluctuations. This result is evidence of the existence of long-range correlations in the fluctuations. Furthermore, we employed shuffle and surrogate approaches to analyze the origins of multifractality. Comparing the MF-DFA results for the data set to those for shuffled and surrogate series, we have found that its multifractal nature is due to the existence of significant long-term correlation.

  2. Synthesis of magnetic nanoparticles by atmospheric-pressure glow discharge plasma-assisted electrolysis

    Science.gov (United States)

    Shirai, Naoki; Yoshida, Taketo; Uchida, Satoshi; Tochikubo, Fumiyoshi

    2017-07-01

    For the synthesis of magnetic nanoparticles (NPs), we used plasma-assisted electrolysis in which atmospheric-pressure DC glow discharge using a liquid electrode is combined with electrolysis. The solution surface is exposed to positive ions or electrons in plasma. To synthesize magnetic NPs, aqueous solutions of FeCl2 or an iron electrode immersed in liquid was used to supply iron ions in the liquid. Magnetic NPs were synthesized at the plasma-liquid interface upon the electron irradiation of the liquid surface. In the case of using aqueous solutions of FeCl2, the condition of magnetic NP synthesis depended on the gas species of plasma and the chemical agent in the liquid for controlling oxidization. The amount of magnetic NPs synthesized using plasma is not very large. On the other hand, in the case of using an iron electrode immersed in NaCl solution, magnetic NPs were synthesized without using FeCl2 solutions. When plasma-assisted electrolysis was operated, the iron electrode eluted Fe cations, resulting in the formation of magnetic NPs at the plasma-liquid interface. Magnetic NP synthesis depended on the concentration of NaCl solution and discharge current. The magnetic NPs were identified to be magnetite. By using this method, more magnetite NPs were synthesized than in the case of plasma-assisted electrolysis with FeCl2 aqueous solutions. The pH of the liquid used in plasma-assisted electrolysis was important for the synthesis of magnetite NPs.

  3. Investigation of Gas Heating by Nanosecond Repetitively Pulsed Glow Discharges Used for Actuation of a Laminar Methane-Air Flame

    KAUST Repository

    Lacoste, Deanna

    2017-05-24

    This paper reports on the quantification of the heating induced by nanosecond repetitively pulsed (NRP) glow discharges on a lean premixed methane-air flame. The flame, obtained at room temperature and atmospheric pressure, has an M-shape morphology. The equivalence ratio is 0.95 and the thermal power released by the flame is 113 W. The NRP glow discharges are produced by high voltage pulses of 10 ns duration, 7 kV amplitude, applied at a repetition frequency of 10 kHz. The average power of the plasma, determined from current and voltage measurements, is 1 W, i.e. about 0.9 % of the thermal power of the flame. Broadband vibrational coherent anti-Stokes Raman spectroscopy of nitrogen is used to determine the temperature of the flame with and without plasma enhancement. The temperature evolution in the flame area shows that the thermal impact of NRP glow discharges is in the uncertainty range of the technique, i.e., +/- 40 K.

  4. Development of soft ionization using direct current pulse glow discharge plasma source in mass spectrometry for volatile organic compounds analysis

    Science.gov (United States)

    Nunome, Yoko; Kodama, Kenji; Ueki, Yasuaki; Yoshiie, Ryo; Naruse, Ichiro; Wagatsuma, Kazuaki

    2018-01-01

    This study describes an ionization source for mass analysis, consisting of glow discharge plasma driven by a pulsed direct-current voltage for soft plasma ionization, to detect toxic volatile organic compounds (VOCs) rapidly and easily. The novelty of this work is that a molecular adduct ion, in which the parent molecule attaches with an NO+ radical, [M + NO]+, can be dominantly detected as a base peak with little or no fragmentation of them in an ambient air plasma at a pressure of several kPa. Use of ambient air as the discharge plasma gas is suitable for practical applications. The higher pressure in an ambient air discharge provided a stable glow discharge plasma, contributing to the soft ionization of organic molecules. Typical mass spectra of VOCs toluene, benzene, o-xylene, chlorobenzene and n-hexane were observed as [M + NO]+ adduct ion whose peaks were detected at m/z 122, 108, 136, 142 and 116, respectively. The NO generation was also confirmed by emission bands of NO γ-system. The ionization reactions were suggested, such that NO+ radical formed in an ambient air discharge could attach with the analyte molecule.

  5. Non-self-sustained discharge with hollow anode for plasma-based surface treatment

    Directory of Open Access Journals (Sweden)

    Misiruk Ivan O.

    2016-06-01

    Full Text Available The paper discusses plasma methods for surface modification using the non-self-sustained glow discharge with a hollow anode. This discharge is characterised by low voltage and high values of electron and ion currents. It can be easily excited in vacuum-arc installations that are widely used for coatings deposition. It is shown that such type of discharge may be effectively used for ion pumping, film deposition, ion etching, diffusion saturation of metallic materials, fusion and brazing of metals, and for combined application of above mentioned technologies in a single vacuum cycle.

  6. Preliminary fluid channel design and thermal-hydraulic analysis of glow discharge cleaning permanent electrode

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Lijun, E-mail: cailj@swip.ac.cn [Southwestern Institute of Physics, Chengdu (China); Lin, Tao; Wang, Yingqiao; Wang, Mingxu [Southwestern Institute of Physics, Chengdu (China); Maruyama, So; Yang, Yu; Kiss, Gabor [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

    2016-11-01

    Highlights: • The plasma facing closure cap has to survive after 30,000 thermal heat load cycles. • 0.35 MW/m2 radiation heat load plus nuclear heat load are very challenging for stainless steel. • Multilayer structure has been designed by using advanced welding and drilling technology to solve the neutron heating problem. • Accurate volumetric load application in analysis model by CFX has been mastered. - Abstract: Glow discharge cleaning (GDC) shall be used on ITER device to reduce and control impurity and hydrogenic fuel out-gassing from in-vessel plasma facing components. After first plasma, permanent electrode (PE) will be used to replace Temporary Electrode (TE) for subsequent operation. Two fundamental scenarios i.e., GDC and Plasma Operation State (POS) should be considered for electrode design, which requires the heat load caused by plasma radiation and neutron heating must be taken away by cooling water flowing inside the electrode. In this paper, multilayer cooling channels inside PE are preliminarily designed, and snakelike route in each layer is adopted to improve the heat exchange. Detailed thermal-hydraulic analyses have been done to validate the design feasibility or rationality. The analysis results show that during GDC the cooling water inlet and outlet temperature difference is far less than the allowable temperature rise under water flow rate 0.15 kg/s compromised by many factors. For POS, the temperature rise and pressure drop are within the design goals, but high thermal stress occurs on the front surface of closure cap of electrode. After several iterations of optimization of the closure cap, the equivalent strain range after 30,000 loading cycles for POS is well below 0.3% design goals.

  7. Effects of rf power on chemical composition and surface roughness of glow discharge polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ling; He, Xiaoshan; Chen, Guo; Wang, Tao; Tang, Yongjian; He, Zhibing, E-mail: hezhibing802@163.com

    2016-03-15

    Graphical abstract: - Highlights: • The growth mechanism of defects in GDP films was studied upon plasma diagnosis. • Increasing rf power enhanced the etching effects of smaller-mass species. • The “void” defect was caused by high energy hydrocarbons bombardment on the surface. • The surface roughness was only 12.76 nm, and no “void” defect was observed at 30 W. - Abstract: The glow discharge polymer (GDP) films for laser fusion targets were successfully fabricated by plasma enhanced chemical vapor deposition (PECVD) at different radio frequency (rf) powers. The films were deposited using trans-2-butene (T{sub 2}B) mixed with hydrogen as gas sources. The composition and state of plasma were diagnosed by quadrupole mass spectrometer (QMS) and Langmuir probe during the deposition process. The composition, surface morphology and roughness were investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and white-light interferometer (WLI), respectively. Based on these observation and analyses, the growth mechanism of defects in GDP films were studied. The results show that, at low rf power, there is a larger probability for secondary polymerization and formation of multi-carbon C-H species in the plasma. In this case, the surface of GDP film turns to be cauliflower-like. With the increase of rf power, the degree of ionization is high, the relative concentration of smaller-mass hydrocarbon species increases, while the relative concentration of larger-mass hydrocarbon species decreases. At higher rf power, the energy of smaller-mass species are high and the etching effects are strong correspondingly. The GDP film's surface roughness shows a trend of decrease firstly and then increase with the increasing rf power. At rf power of 30 W, the surface root-mean-square roughness (Rq) drops to the lowest value of 12.8 nm, and no “void” defect was observed.

  8. ULTRAVIOLET INDUCED MOTION OF A FLUORESCENT DUST CLOUD IN AN ARGON DIRECT CURRENT GLOW DISCHARGE PLASMA

    Energy Technology Data Exchange (ETDEWEB)

    Hvasta, M.G.; and Zwicker, A.

    2008-01-01

    Dusty plasmas consist of electrons, ions, neutrals and nm-μm sized particles commonly referred to as dust. In man-made plasmas this dust may represent impurities in a tokamak or plasma etching processing. In astrophysical plasmas this dust forms structures such as planetary rings and comet tails. To study dusty plasma dynamics an experiment was designed in which a 3:1 silica (<5 μm diameter) and fl uorescent dust mixture was added to an argon DC glow discharge plasma and exposed to UV radiation. This fl uorescent lighting technique offers an advantage over laser scattering (which only allows two-dimensional slices of the cloud to be observed) and is simpler than scanning mirror techniques or particle image velocimetry. Under typical parameters (P=150 mTorr, V anode= 100 V, Vcathode= -400 V, Itotal < 2mA) when the cloud is exposed to the UV light (100W, λ = 365 nm) the mixture fl uoresces, moves ~2mm towards the light source and begins rotating in a clockwise manner (as seen from the cathode). By calibrating a UV lamp and adjusting the relative intensity of the UV with a variable transformer it was found that both translational and rotational velocities are a function of UV intensity. Additionally, it was determined that bulk cloud rotation is not seen when the dust tray is not grounded while bulk translation is. This ongoing experiment represents a novel way to control contamination in man-made plasmas and a path to a better understanding of UV-bathed plasma systems in space..

  9. Heat and Radiofrequency Plasma Glow Discharge Pretreatment of a Titanium Alloy: Eveidence for Enhanced Osteoinductive Properties

    Science.gov (United States)

    Rapuano, Bruce E.; Singh, Herman; Boskey, Adele L.; Doty, Stephen B.; MacDonald, Daniel E.

    2013-01-01

    It is believed that orthopedic and implant longevity can be improved by optimizing fixation, or direct bone-implant contact, through the stimulation of new bone formation around the implant. The purpose of this study was to determine whether heat (600°C) or radiofrequency plasma glow discharge (RFGD) pretreatment of Ti6Al4V stimulated calcium-phosphate mineral formation in cultures of attached MC3T3 osteoprogenitor cells with or without a fibronectin coating. Calcium-phosphate mineral was analyzed by flame atomic absorption spectrophotometry, scanning electron microscopy (SEM)/electron dispersive X-ray microanalysis (EDAX) and Fourier transformed infrared spectroscopy (FTIR). RFGD and heat pretreatments produced a general pattern of increased total soluble calcium levels, although the effect of heat pretreatment was greater than that of RFGD. SEM/EDAX showed the presence of calcium-and phosphorus-containing particles on untreated and treated disks that were more numerous on fibronectin-coated disks. These particles were observed earliest (1 week) on RFGD-pretreated surfaces. FTIR analyses showed that the heat pretreatment produced a general pattern of increased levels of apatite mineral at 2–4 weeks; a greater effect was observed for fibronectin-coated disks compared to uncoated disks. The observed findings suggest that heat pretreatment of Ti6Al4V increased the total mass of the mineral formed in MC3T3 osteoprogenitor cell cultures more than RFGD while the latter pretreatment hastened the early deposition of mineral. These findings help to support the hypothesis that the pretreatments enhance the osteoinductive properties of the alloy. PMID:23494951

  10. Design and characterization of a radio-frequency-powered glow discharge source for double-focusing mass spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Duckworth, D.C.; Donohue, D.L.; Smith, D.H.; Lewis, T.A. (Oak Ridge National Lab., TN (United States)); Marcus, R. K. (Clemson Univ., SC (United States))

    1993-09-15

    A radio-frequency- (rf-) powered glow discharge has been interfaced to a double-focusing mass spectrometer. This type of discharge allows direct analysis of nonconducting, as well as conducting, solids. The rf discharge source and electrical system overcome several problems which have inhibited success in prior efforts. Problems of inadequate rf shielding, maintaining the necessary dc bias potential on the sample surface, preventing rf modulation of ion energies, and coupling of the accelerating potential to the discharge are resolved. Representative spectra of glass, soil, and brass matrices are presented. Preliminary relative sensitivity factors for conducting and non-conducting matrices show relatively small differences in ion yields across the periodic table. 31 refs., 9 figs., 2 tabs.

  11. Estimating the parameters of a positive column of the halogen-containing glow discharge at moderate pressures

    Directory of Open Access Journals (Sweden)

    Alexander P. Golovitskii

    2015-03-01

    Full Text Available The methodical recommendations for estimating the plasma parameters of an electronegative glow discharge containing halogens at moderate pressures (up to 40 Torr with the use of simple analytic formulae and without numerical modeling are given. The initial data are easily measureable discharge parameters such as a discharge current, a voltage and a gas mixture pressure and composition as well. It is shown how one can easily consider such important plasma features as non-Maxwellian electron energy distribution function and halogen molecules dissociation by electron impact. As a result, such plasma parameters as the absolute degree of electronegativity, the value of border coordinate between ion–ion and electron–ion plasmas, and the forms of transversal profiles of electron and negative ion concentrations can be evaluated. The comparison of the results with the ones given by a global numerical model shows the suitability of said analytic approach to estimate plasma parameters of real discharges.

  12. Behavior of hydrogen atoms in boron films during H{sub 2} and He glow discharge and thermal desorption

    Energy Technology Data Exchange (ETDEWEB)

    Tsuzuki, K.; Natsir, M.; Inoue, N. [and others

    1995-09-01

    Hydrogen absorption and desorption characteristics in boron films deposited on a graphite liner have been studied. Number of hydrogen atoms absorbed in the films is estimated from a decrease in hydrogen pressure during a hydrogen glow discharge. It was 1.9 x 10{sup 17} atoms/cm{sup 2} in the 1 hour discharge after an evacuation of H atoms contained in the original boron films by thermal desorption. Hydrogen atoms were absorbed continuously without saturation for 3 hours during the discharge. Number of H atoms absorbed reached to 2.6 x 10{sup 17} atoms/cm{sup 2} at 3 hour. A discharge in helium was carried out to investigate H desorption characteristics from hydrogen implanted boron films. It was verified that reactivity for hydrogen absorption was recovered after the He discharge. Hydrogen atoms were accumulated in the films by repetition of alternate He and H{sub 2} discharge. Thermal desorption experiments have been carried out by raising the liner temperature up to 500degC for films after 1 hour, 3 hours hydrogen discharge and 6 times repetition of H{sub 2}/He discharges. Most of H atoms in the films were desorbed for all these cases. The slow absorption process was confirmed through the thermal desorption experiments. (author).

  13. Ab initio and experimental studies of glow-discharge polymer used in laser mégajoule capsules

    Science.gov (United States)

    Colin-Lalu, P.; Recoules, V.; Salin, G.; Huser, G.

    2017-01-01

    The equations of state tables used in Inertial Confinement Fusion Capsule design tools are highly dependent on the cold curve in the multimegabar pressure range. Original ab initio molecular dynamic simulations were performed to get accurate cold curves of glow-discharge polymer (GDP) plastics. Furthermore the effect of oxygen absorption by GDP structure is studied on the cold curve, as well as its impact on the Hugoniot curves. Results are compared with the Hugoniot experimental data obtained in a recent experiment at the LULI2000 laser facility in France. This study leads to improve the equation of states knowledge of ablator materials, which is of primary importance for NIF and LMJ experiments.

  14. High-photosensitivity a-SiGe: H films prepared by RF glow discharge plasma CVD method

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Fangqing (Dept. of Physics, Lanzhou Univ. (China)); Song Zhizhong (Dept. of Physics, Lanzhou Univ. (China)); Guo Yongping (Dept. of Physics, Lanzhou Univ. (China)); Chen Guanghua (Dept. of Physics, Lanzhou Univ. (China))

    1993-04-01

    Highly photosensitive and narrow band gap a-SiGe:H films have been prepared by the RF glow discharge plasma CVD method. The photosensitivity was 2.01x10[sup 5] for the film with an optical band gap of E[sub g]=1.47 eV. H[sub 2] dilution and a relatively high RF power are attributed to the improving of the optoelectrical properties. Thermally induced changes of the a-SiGe:H films have been also investigated. (orig.)

  15. Setting-up of the Laser Induced Fluorescence diagnostic. Measurements of Cr density in a neon glow discharge; Puesta a punto del diagnstico de fluorescencia inducida por laser. Medidas de densidad de Cr en Glow discharg de Neon

    Energy Technology Data Exchange (ETDEWEB)

    Tafalla, D.; Cal, E. de la; Tabares, F. L.

    1994-07-01

    A plasma diagnostic based on the Laser Induced Fluorescence (LIF) technique has been set up in the Fusion Division at the CIEMAT. In a preliminary experiment, the density of sputtered chromium atoms produced in a neon glow discharge was measured. Firstly, the laser beam was characterized by calibration of its wavelength, bandwidth and energy profile and Rayleigh scattering in N2 was used for the optical system calibration. An absolute density of Cr atoms of n {approx} 5x10 cm was obtained in discharges at 100 mA and pressure of 15 mTorr and a linear dependence of the LIF signal us. current was found. These values are in agreement with those expected from the tabulated sputtering yields and the thermalization and diffusion of the sputtered atoms into the Ne plasma. (Author) 19 refs.

  16. Relationship between Plasma Parameters and Carbon Atom Coordination in a-C:H Films Prepared by RF Glow Discharge Decomposition

    Science.gov (United States)

    Yamamoto, Kenji; Ichikawa, Yosuke; Nakayama, Takehisa; Tawada, Yoshihisa

    1988-08-01

    Amorphous C:H films were prepared by rf glow discharge decomposition from CH4 using a permanent magnet system to apply a static magnetic field perpendicular to the rf electric field. The structure and properties of a-C:H films have been investigated systematically with respect to the hydrogen content, hardness and coordination of carbon atoms as a function of rf power (self-bias voltage). The coordination of carbon atoms has been determined by solid-state 13C magic angle spinning nuclear magnetic resonance measurements. It is found that the fraction of graphitic (sp2) versus tetrahedral (sp3) bonding increases with increasing rf power (negative self-bias voltage). Film hardness is understood in terms of the balance between the incorporated hydrogen and the fraction of graphitic (sp2) versus tetrahedral (sp3) bonding. The production of ionic and neutral species from a glow discharge has also been monitored by mass spectroscopy and optical emission spectroscopy to investigate the relation between plasma parameters and carbon atom coordination. Using these measurements and negative self-bias measurements, it is shown that the coordination of carbon atoms is determined not only by the energy of impinging ions on the substrate but also by the type of active species. In addition, the neutral and ionic C2H2 related species are thought to be some of the species which increase the fraction of graphitic (sp2) versus tetrahedral (sp3) bonding.

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

    Science.gov (United States)

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

    2011-02-01

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

  18. A study of internal oxidation in carburized steels by glow discharge optical emission spectroscopy and scanning electron microscopy

    CERN Document Server

    An, X; Rainforth, W M; Chen, L

    2003-01-01

    The internal oxidation of Cr-Mn carburizing steel was studied. Internal oxidation was induced using a commercial carburizing process. Sputter erosion coupled with glow discharge optical emission spectroscopy (GDOES) was used to determine the depth profile elemental distribution within the internal oxidation layer (<10 mu m). In addition, scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) studies were carried out on selected sputter eroded surfaces. Oxide type was identified primarily by transmission electron microscopy (TEM). The carburized surface was found to consist of a continuous oxide layer, followed by a complex internal oxidation layer, where Cr and Mn oxides were found to populate grain boundaries in a globular form in the near surface region. At greater depths (5-10 mu m), Si oxides formed as a grain boundary network. The internal oxides (mainly complex oxides) grew quickly during the initial stages of the carburizing process (2 h, 800 deg. C+3 h, 930 deg. C). G...

  19. Enhancement of Osteoblastic-Like Cell Activity by Glow Discharge Plasma Surface Modified Hydroxyapatite/β-Tricalcium Phosphate Bone Substitute

    Directory of Open Access Journals (Sweden)

    Eisner Salamanca

    2017-11-01

    Full Text Available Glow discharge plasma (GDP treatments of biomaterials, such as hydroxyapatite/β-tricalcium phosphate (HA/β-TCP composites, produce surfaces with fewer contaminants and may facilitate cell attachment and enhance bone regeneration. Thus, in this study we used argon glow discharge plasma (Ar-GDP treatments to modify HA/β-TCP particle surfaces and investigated the physical and chemical properties of the resulting particles (HA/β-TCP + Ar-GDP. The HA/β-TCP particles were treated with GDP for 15 min in argon gas at room temperature under the following conditions: power: 80 W; frequency: 13.56 MHz; pressure: 100 mTorr. Scanning electron microscope (SEM observations showed similar rough surfaces of HA/β-TCP + Ar-GDP HA/β-TCP particles, and energy dispersive spectrometry analyses showed that HA/β-TCP surfaces had more contaminants than HA/β-TCP + Ar-GDP surfaces. Ca/P mole ratios in HA/β-TCP and HA/β-TCP + Ar-GDP were 1.34 and 1.58, respectively. Both biomaterials presented maximal intensities of X-ray diffraction patterns at 27° with 600 a.u. At 25° and 40°, HA/β-TCP + Ar-GDP and HA/β-TCP particles had peaks of 200 a.u., which are similar to XRD intensities of human bone. In subsequent comparisons, MG-63 cell viability and differentiation into osteoblast-like cells were assessed on HA/β-TCP and HA/β-TCP + Ar-GDP surfaces, and Ar-GDP treatments led to improved cell growth and alkaline phosphatase activities. The present data indicate that GDP surface treatment modified HA/β-TCP surfaces by eliminating contaminants, and the resulting graft material enhanced bone regeneration.

  20. Influence of Operating Parameters on Surface Properties of RF Glow Discharge Oxygen Plasma Treated TiO2/PET Film for Biomedical Application

    Science.gov (United States)

    Thin transparent titania (TiO2) films were coated on the surface of flexible poly (ethylene terephthalate) (PET) surface using standard sol gel techniques. The TiO2/PET thin film surfaces were further modified by exposing the films to a RF glow discharge oxygen plasma. The exposu...

  1. Improved platelet compatiblity of water vapour glow discharge treated non-woven poly(ethylene terephthalate) leukocyte-reduction filters for different types of platelet concentrates

    NARCIS (Netherlands)

    Kostelijk, E. H.; Klomp, A. J.; Engbers, G. H.; Gouwerok, C. W.; Verhoeven, A. J.; van Aken, W. G.; Feijen, J.; de Korte, D.

    2001-01-01

    Non-woven poly[ethylene terephthalate] (NW-PET) filter fabric, usually used for leucocyte removal of red cells, was modified by water vapour glow discharge (WVGD) treatment to improve platelet compatibility. Modified filter material was evaluated with different kinds of platelet concentrates (PCs).

  2. Improved platelet compatibility of water vapour glow discharge treated non-woven poly(ethylene therephthalate) leukocyte-reduction filters of different types of platelet concentrates

    NARCIS (Netherlands)

    Kostelijk, E.H.; Klomp, A.J.A.; Klomp, A.J.A.; Engbers, G.H.M.; Gouwerok, C.W.N.; van Aken, W.G.; Verhoeven, A.J.; Feijen, Jan; de Korte, D.

    2001-01-01

    Non-woven poly[ethylene terephthalate] (NW-PET) filter fabric, usually used for leucocyte removal of red cells, was modified by water vapour glow discharge (WVGD) treatment to improve platelet compatibility. Modified filter material was evaluated with different kinds of platelet concentrates (PCs).

  3. Irregular-regular mode oscillations inside plasma bubble and its fractal analysis in glow discharge magnetized plasma

    Science.gov (United States)

    Megalingam, Mariammal; Hari Prakash, N.; Solomon, Infant; Sarma, Arun; Sarma, Bornali

    2017-04-01

    Experimental evidence of different kinds of oscillations in floating potential fluctuations of glow discharge magnetized plasma is being reported. A spherical gridded cage is inserted into the ambient plasma volume for creating plasma bubbles. Plasma is produced between a spherical mesh grid and chamber. The spherical mesh grid of 80% optical transparency is connected to the positive terminal of power supply and considered as anode. Two Langmuir probes are kept in the ambient plasma to measure the floating potential fluctuations in different positions within the system, viz., inside and outside the spherical mesh grid. At certain conditions of discharge voltage (Vd) and magnetic field, irregular to regular mode appears, and it shows chronological changes with respect to magnetic field. Further various nonlinear analyses such as Recurrence Plot, Hurst exponent, and Lyapunov exponent have been carried out to investigate the dynamics of oscillation at a range of discharge voltages and external magnetic fields. Determinism, entropy, and Lmax are important measures of Recurrence Quantification Analysis which indicate an irregular to regular transition in the dynamics of the fluctuations. Furthermore, behavior of the plasma oscillation is characterized by the technique called multifractal detrended fluctuation analysis to explore the nature of the fluctuations. It reveals that it has a multifractal nature and behaves as a long range correlated process.

  4. Glow discharge electrolysis plasma initiated preparation of temperature/pH dual sensitivity reed hemicellulose-based hydrogels.

    Science.gov (United States)

    Zhang, Wenming; Zhu, Sha; Bai, Yunping; Xi, Ning; Wang, Shaoyang; Bian, Yang; Li, Xiaowei; Zhang, Yucang

    2015-05-20

    The temperature/pH dual sensitivity reed hemicellulose-based hydrogels have been prepared through glow discharge electrolysis plasma (GDEP). The effect of different discharge voltages on the temperature and pH response performance of reed hemicellulose-based hydrogels was inspected, and the formation mechanism, deswelling behaviors of reed hemicellulose-based hydrogels were also discussed. At the same time, infrared spectroscopy (FT-IR), scanning differential thermal analysis (DSC) and scanning electron microscope (SEM) were adopted to characterize the structure, phase transformation behaviors and microstructure of hydrogels. It turned out to be that all reed hemicellulose-based hydrogels had a double sensitivity to temperature and pH, and their phase transition temperatures were all approximately 33 °C, as well as the deswelling dynamics met the first model. In addition, the hydrogel (TPRH-3), under discharge voltage 600 V, was more sensitive to temperature and pH and had higher deswelling ratio. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. FAST TRACK COMMUNICATION: Contrasting characteristics of sub-microsecond pulsed atmospheric air and atmospheric pressure helium-oxygen glow discharges

    Science.gov (United States)

    Walsh, J. L.; Liu, D. X.; Iza, F.; Rong, M. Z.; Kong, M. G.

    2010-01-01

    Glow discharges in air are often considered to be the ultimate low-temperature atmospheric pressure plasmas for numerous chamber-free applications. This is due to the ubiquitous presence of air and the perceived abundance of reactive oxygen and nitrogen species in air plasmas. In this paper, sub-microsecond pulsed atmospheric air plasmas are shown to produce a low concentration of excited oxygen atoms but an abundance of excited nitrogen species, UV photons and ozone molecules. This contrasts sharply with the efficient production of excited oxygen atoms in comparable helium-oxygen discharges. Relevant reaction chemistry analysed with a global model suggests that collisional excitation of O2 by helium metastables is significantly more efficient than electron dissociative excitation of O2, electron excitation of O and ion-ion recombination. These results suggest different practical uses of the two oxygen-containing atmospheric discharges, with air plasmas being well suited for nitrogen and UV based chemistry and He-O2 plasmas for excited atomic oxygen based chemistry.

  6. Characterization of an AC glow-type gliding arc discharge in atmospheric air with a current-voltage lumped model

    Science.gov (United States)

    Kong, Chengdong; Gao, Jinlong; Zhu, Jiajian; Ehn, Andreas; Aldén, Marcus; Li, Zhongshan

    2017-09-01

    Quantitative characterization of a high-power glow-mode gliding arc (GM-GA) discharge operated in open air is performed using a current-voltage lumped model that is built from the perspective of energy balance and electron conservation. The GM-GA discharge is powered by a 35 kHz alternating current power supply. Instantaneous images of the discharge volume are recorded using a high-speed camera at a frame rate of 50 kHz, synchronized with the simultaneously recorded current and voltage waveforms. Detailed analyzation indicates that the electrical input power is dissipated mainly through the transport of vibrationally excited nitrogen and other active radicals (such as O). The plasma is quite non-thermal with the ratio of vibrational and translational temperatures (Tv/Tg) larger than 2 due to the intense energy dissipation. The electron number density reaches 3 × 1019 m-3 and is always above the steady value owing to the short cutting events, which can recover the electron density to a relatively large value and limits the maximum length of the gliding arc. The slow decaying rate of electrons is probably attributed to the decomposed state of a hot gaseous mixture and the related associative ionization.

  7. Modification of hydrophobic acrylic intraocular lens with poly(ethylene glycol) by atmospheric pressure glow discharge: A facile approach

    Energy Technology Data Exchange (ETDEWEB)

    Lin Lin; Wang Yao; Huang Xiaodan [Eye Center, Affiliated Second Hospital, College of Medicine, Zhejiang University, Hangzhou 310009 (China); Xu Zhikang [Key Laboratory of Macromolecular Synthesis and Functionalization (Ministry of Education), Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Yao Ke, E-mail: xlren@zju.edu.cn [Eye Center, Affiliated Second Hospital, College of Medicine, Zhejiang University, Hangzhou 310009 (China)

    2010-10-01

    To improve the anterior surface biocompatibility of hydrophobic acrylic intraocular lens (IOL) in a convenient and continuous way, poly(ethylene glycol)s (PEGs) were immobilized by atmospheric pressure glow discharge (APGD) treatment using argon as the discharge gas. The hydrophilicity and chemical changes on the IOL surface were characterized by static water contact angle and X-ray photoelectron spectroscopy to confirm the covalent binding of PEG. The morphology of the IOL surface was observed under field emission scanning electron microscopy and atomic force microscopy. The surface biocompatibility was evaluated by adhesion experiments with platelets, macrophages, and lens epithelial cells (LECs) in vitro. The results revealed that the anterior surface of the PEG-grafted IOL displayed significantly and permanently improved hydrophilicity. Cell repellency was observed, especially in the PEG-modified IOL group, which resisted the attachment of platelets, macrophages and LECs. Moreover, the spread and growth of cells were suppressed, which may be attributed to the steric stabilization force and chain mobility effect of the modified PEG. All of these results indicated that hydrophobic acrylic IOLs can be hydrophilic modified by PEG through APGD treatment in a convenient and continuous manner which will provide advantages for further industrial applications.

  8. Emission characteristics of laser ablation-hollow cathode glow discharge spectral source

    Directory of Open Access Journals (Sweden)

    Karatodorov Stefan

    2014-11-01

    Full Text Available The emission characteristics of a scheme combining laser ablation as sample introduction source and hollow cathode discharge as excitation source are presented. The spatial separation of the sample material introduction by laser ablation and hollow cathode excitation is achieved by optimizing the gas pressure and the sample-cathode gap length. At these conditions the discharge current is maximized to enhance the analytical lines intensity.

  9. Glow Discharge Emission Spectrometry (GDOES): Theoretical Introduction, General Aspects, and its Applications within the Framework of the Technofusion Programs; Glow Discharge Emission Spectrometry (GDOES): Introduccion Teorica, Aspectos Generales y Aplicabilidad en el Marco del Programa Technofusion

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Rojo, A. B.; Gonzalez, M.; Tabares, F. L.

    2013-02-01

    The demand by material research groups for the direct composition analysis of solids is increasing as a solution to the time-consuming problems and errors inherent to classical chemical analysis, where the attack and solubilisation of the starting material is mandatory, often producing the introduction of impurities and component loss of the initial matrix. From the existing solid analysis techniques the present work is focused on the Glow Discharge Emission Spectrometry (GDOES), a fast, simply-executed technique, for which quantitative, high resolution depth profile determination of any element in the periodic table can be performed with a high sensibility and detection limit. The theoretical concepts, the required instrumentation and the basic analytic applications are revised, giving especial attention to the issues related to the analysis of materials for fusion applications. Finally, a comparative study with a more advanced spectroscopic technique (Secondary Ion Mass Spectrometry (SIMS)) is performed and the concomitance of both techniques to correct limitations such as the spatial resolution and the quantification of the analysis, important factors that are required in the chemical analysis of the complex materials used in Fusion, is addressed. (Author) 41 refs.

  10. Comparison of dielectric barrier discharge, atmospheric pressure radiofrequency-driven glow discharge and direct analysis in real time sources for ambient mass spectrometry of acetaminophen

    Science.gov (United States)

    Kratzer, Jan; Mester, Zoltán; Sturgeon, Ralph E.

    2011-08-01

    Three plasma-based ambient pressure ion sources were investigated; laboratory constructed dielectric barrier and rf glow discharges, as well as a commercial corona discharge (DART source). All were used to desorb and ionize a model analyte, providing sampling techniques for ambient mass spectrometry (MS). Experimental parameters were optimized to achive highest signal for acetaminophen as the analyte. Insight into the mechanisms of analyte desorption and ionization was obtained by means of emission spectrometry and ion current measurements. Desorption and ionization mechanisms for this analyte appear to be identical for all three plasma sources. Emission spectra differ only in the intensities of various lines and bands. Desorption of solid analyte requires transfer of thermal energy from the plasma source to sample surface, in the absence of which complete loss of MS response occurs. For acetaminophen, helium was the best plasma gas, providing 100- to 1000-fold higher analyte response than with argon or nitrogen. The same trend was also evident with background ions (protonated water clusters). MS analyte signal intensity correlates with the ion density (expressed as ion current) in the plasma plume and with emission intensity from excited state species in the plasma. These observations support an ionization process which occurs via proton transfer from protonated water clusters to analyte molecules.

  11. Comparison of dielectric barrier discharge, atmospheric pressure radiofrequency-driven glow discharge and direct analysis in real time sources for ambient mass spectrometry of acetaminophen

    Energy Technology Data Exchange (ETDEWEB)

    Kratzer, Jan [Institute for National Measurement Standards, National Research Council of Canada, 1200 Montreal Road, Ottawa, Ontario, K1A 0R6 (Canada); Institute of Analytical Chemistry of the ASCR, v.v.i., Veveri 97, CZ-602 00 Brno (Czech Republic); Mester, Zoltan [Institute for National Measurement Standards, National Research Council of Canada, 1200 Montreal Road, Ottawa, Ontario, K1A 0R6 (Canada); Sturgeon, Ralph E., E-mail: Ralph.Sturgeon@nrc-cnrc.gc.ca [Institute for National Measurement Standards, National Research Council of Canada, 1200 Montreal Road, Ottawa, Ontario, K1A 0R6 (Canada)

    2011-08-15

    Three plasma-based ambient pressure ion sources were investigated; laboratory constructed dielectric barrier and rf glow discharges, as well as a commercial corona discharge (DART source). All were used to desorb and ionize a model analyte, providing sampling techniques for ambient mass spectrometry (MS). Experimental parameters were optimized to achive highest signal for acetaminophen as the analyte. Insight into the mechanisms of analyte desorption and ionization was obtained by means of emission spectrometry and ion current measurements. Desorption and ionization mechanisms for this analyte appear to be identical for all three plasma sources. Emission spectra differ only in the intensities of various lines and bands. Desorption of solid analyte requires transfer of thermal energy from the plasma source to sample surface, in the absence of which complete loss of MS response occurs. For acetaminophen, helium was the best plasma gas, providing 100- to 1000-fold higher analyte response than with argon or nitrogen. The same trend was also evident with background ions (protonated water clusters). MS analyte signal intensity correlates with the ion density (expressed as ion current) in the plasma plume and with emission intensity from excited state species in the plasma. These observations support an ionization process which occurs via proton transfer from protonated water clusters to analyte molecules.

  12. Quantification of scaling exponent with Crossover type phenomena for different types of forcing in DC glow discharge plasma

    Science.gov (United States)

    Saha, Debajyoti; Shaw, Pankaj Kumar; Ghosh, Sabuj; Janaki, M. S.; Sekar Iyengar, A. N.

    2018-01-01

    We have carried out a detailed study of scaling region using detrended fractal analysis test by applying different forcing likewise noise, sinusoidal, square on the floating potential fluctuations acquired under different pressures in a DC glow discharge plasma. The transition in the dynamics is observed through recurrence plot techniques which is an efficient method to observe the critical regime transitions in dynamics. The complexity of the nonlinear fluctuation has been revealed with the help of recurrence quantification analysis which is a suitable tool for investigating recurrence, an ubiquitous feature providing a deep insight into the dynamics of real dynamical system. An informal test for stationarity which checks for the compatibility of nonlinear approximations to the dynamics made in different segments in a time series has been proposed. In case of sinusoidal, noise, square forcing applied on fluctuation acquired at P = 0.12 mbar only one dominant scaling region is observed whereas the forcing applied on fluctuation (P = 0.04 mbar) two prominent scaling regions have been explored reliably using different forcing amplitudes indicating the signature of crossover phenomena. Furthermore a persistence long range behavior has been observed in one of these scaling regions. A comprehensive study of the quantification of scaling exponents has been carried out with the increase in amplitude and frequency of sinusoidal, square type of forcings. The scalings exponent is envisaged to be the roughness of the time series. The method provides a single quantitative idea of the scaling exponent to quantify the correlation properties of a signal.

  13. Investigation of working pressure on the surface roughness controlling technology of glow discharge polymer films based on the diagnosed plasma

    Science.gov (United States)

    Zhang, Ling; Chen, Guo; He, Zhibing; Ai, Xing; Huang, Jinglin; Liu, Lei; Tang, Yongjian; He, Xiaoshan

    2017-07-01

    The effects of working pressure on the component, surface morphology, surface roughness, and deposition rate of glow discharge polymer (GDP) films by a trans-2-butene/hydrogen gas mixture were investigated based on plasma characteristics diagnosis. The composition and ion energy distributions of a multi-carbon (C4H8/H2) plasma mixture at different working pressures were diagnosed by an energy-resolved mass spectrometer (MS) during the GDP film deposition process. The Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (SEM) and white-light interferometer (WLI) results were obtained to investigate the structure, morphology and roughness characterization of the deposited films, respectively. It was found that the degree of ionization of the C4H8/H2 plasma reduces with an increase in the working pressure. At a low working pressure, the C-H fragments exhibited small-mass and high ion energy in plasma. In this case, the film had a low CH3/CH2 ratio, and displayed a smooth surface without any holes, cracks or asperities. While the working pressure increased to 15 Pa, the largest number of large-mass fragments led to the deposition rate reaching a maximum of 2.11 μm h-1, and to hole defects on the film surface. However, continuing to increase the working pressure, the film surface became smooth again, and the interface between clusters became inconspicuous without etching pits.

  14. Atmospheric pressure glow discharge generated in nitrogen-methane gas mixture: PTR-MS analyzes of the exhaust gas

    Science.gov (United States)

    Torokova, Lucie; Mazankova, Vera; Krcma, Frantisek; Mason, Nigel J.; Matejcik, Stefan

    2015-07-01

    This paper reports the results of an extensive study of with the in situ mass spectrometry analysis of gaseous phase species produced by an atmospheric plasma glow discharge in N2-CH4 gas mixtures (with methane concentrations ranging from 1% to 4%). The products are studied using proton-transfer-reaction mass spectrometry (PTR-MS). HCN and CH3CN are identified as the main gaseous products. Hydrazine, methanimine, methyldiazene, ethylamine, cyclohexadiene, pyrazineacetylene, ethylene, propyne and propene are identified as minor compounds. All the detected compounds and their relative abundances are determined with respect to the experimental conditions (gas composition and applied power). The same molecules were observed by the Cassini-Huygens probe in Titan's atmosphere (which has same N2-CH4 gas mixtures). Such, experiments show that the formation of such complex organics in atmospheres containing C, N and H, like that of Titan, could be a source of prebiotic molecules. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  15. Low Pressure DC Glow Discharge Air Plasma Surface Treatment of Polyethylene (PE) Film for Improvement of Adhesive Properties

    Science.gov (United States)

    Krishnasamy Navaneetha, Pandiyaraj; Vengatasamy, Selvarajan; Rajendrasing, R. Deshmukh; Paramasivam, Yoganand; Suresh, Balasubramanian; Sundaram, Maruthamuthu

    2013-01-01

    The present work deals with the change in surface properties of polyethylene (PE) film using DC low pressure glow discharge air plasma and makes it useful for technical applications. The change in hydrophilicity of the modified PE film surface was investigated by measuring contact angle and surface energy as a function of exposure time. Changes in the morphological and chemical composition of PE films were analyzed by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The improvement in adhesion was studied by measuring T-peel and lap-shear strength. The results show that the wettability and surface energy of the PE film has been improved due to the introduction of oxygen-containing polar groups and an increase in surface roughness. The XPS result clearly shows the increase in concentration of oxygen content and the formation of polar groups on the polymer surface. The AFM observation on PE film shows that the roughness of the surface increased due to plasma treatment. The above morphological and chemical changes enhanced the adhesive properties of the PE film surfaces, which was confirmed by T-peel and lap-shear tests.

  16. Comprehensive Evaluation of the Properties of Nanocrystalline Diamond Coatings Grown Using CVD with E/H Field Glow Discharge Stabilization

    Directory of Open Access Journals (Sweden)

    Iu. Nasieka

    2015-01-01

    Full Text Available The nanocrystalline diamond films (coatings were prepared using the plasma enhanced chemical vapor deposition (PECVD technique. In this method, direct current (DC glow discharge in the crossed E/H fields was used to activate the gas phase. The diamond coatings were deposited from the working gas mixture CH4/H2 with addition of nitrogen in various concentrations. It was ascertained that addition of N2 to the working gas mixture leads to reduction in the sizes of diamond grains as well as to the substantial decrease in the resistivity of the studied films. The electrophysical data are in good agreement with the changes induced by varying the N2 content in the Raman scattering spectra. The increase in the N2 concentration causes significant lowering of the crystalline diamond related peak and increase in the intensity of the peaks related to the sp2-bonded carbon. These changes in the spectra indicate significant disordering of the structure of prepared films and its uniformity in the nanodiamond film volume. With the great possibility, it is associated with a decrease in the sizes of diamond crystalline grains and tendency of NCD film to amorphization.

  17. Depth Profile Analysis of Amorphous Silicon Thin Film Solar Cells by Pulsed Radiofrequency Glow Discharge Time of Flight Mass Spectrometry

    Science.gov (United States)

    Alvarez-Toral, Aitor; Sanchez, Pascal; Menéndez, Armando; Pereiro, Rosario; Sanz-Medel, Alfredo; Fernández, Beatriz

    2015-02-01

    Among the different solar cell technologies, amorphous silicon (a-Si:H) thin film solar cells (TFSCs) are today very promising and, so, TFSCs analytical characterization for quality control issues is increasingly demanding. In this line, depth profile analysis of a-Si:H TFSCs on steel substrate has been investigated by using pulsed radiofrequency glow discharge-time of flight mass spectrometry (rf-PGD-TOFMS). First, to discriminate potential polyatomic interferences for several analytes (e.g., 28Si+, 31P+, and 16O+) appropriate time positions along the GD pulse profile were selected. A multi-matrix calibration approach, using homogeneous certified reference materials without hydrogen as well as coated laboratory-made standards containing hydrogen, was employed for the methodological calibration. Different calibration strategies (in terms of time interval selection on the pulse profile within the afterglow region) have been compared, searching for optimal calibration graphs correlation. Results showed that reliable and fast quantitative depth profile analysis of a-Si:H TFSCs by rf-PGD-TOFMS can be achieved.

  18. Fluorine and boron co-doped diamond-like carbon films deposited by pulsed glow discharge plasma immersion ion processing

    CERN Document Server

    He, X M; Peters, A M; Taylor, B; Nastasi, M

    2002-01-01

    Fluorine (F) and boron (B) co-doped diamond-like carbon (FB-DLC) films were prepared on different substrates by the plasma immersion ion processing (PIIP) technique. A pulse glow discharge plasma was used for the PIIP deposition and was produced at a pressure of 1.33 Pa from acetylene (C sub 2 H sub 2), diborane (B sub 2 H sub 6), and hexafluoroethane (C sub 2 F sub 6) gas. Films of FB-DLC were deposited with different chemical compositions by varying the flow ratios of the C sub 2 H sub 2 , B sub 2 H sub 6 , and C sub 2 F sub 6 source gases. The incorporation of B sub 2 H sub 6 and C sub 2 F sub 6 into PIIP deposited DLC resulted in the formation of F-C and B-C hybridized bonding structures. The levels of the F and B concentrations effected the chemical bonding and the physical properties as was evident from the changes observed in density, hardness, stress, friction coefficient, and contact angle of water on films. Compared to B-doped or F-doped DLC films, the F and B co-doping of DLC during PIIP deposition...

  19. Depth profile characterization of Zn-TiO2 nanocomposite films by pulsed radiofrequency glow discharge-optical emission spectrometry.

    Science.gov (United States)

    Alberts, Deborah; Fernández, Beatriz; Frade, Tania; Gomes, Anabela; Pereira, Maria Isabel da Silva; Pereiro, Rosario; Sanz-Medel, Alfredo

    2011-04-15

    In recent years particular effort is being devoted towards the development of radiofrequency (rf) pulsed glow discharges (GDs) coupled to optical emission spectrometry (OES) for depth profile analysis of materials with technological interest. In this work, pulsed rf-GD-OES is investigated for the fast and sensitive depth characterization of Zn-TiO(2) nanocomposite films deposited on conductive substrates (Ti and steel). The first part of this work focuses on assessing the advantages of pulsed GDs, in comparison with the continuous GD, in terms of analytical emission intensities and emission yields. Next, the capability of pulsed rf-GD-OES for determination of thickness and compositional depth profiles is demonstrated by resorting to a simple multi-matrix calibration procedure. A rf forward power of 75 W, a pressure of 600 Pa, 10 kHz pulse frequency and 50% duty cycle were selected as GD operation parameters.Quantitative depth profiles obtained with the GD proposed methodology for Zn-TiO(2) nanocomposite films, prepared by the occlusion electrodeposition method using pulsed reverse current electrolysis, have proved to be in good agreement with results achieved by complementary techniques, including scanning electron microscopy and inductively coupled plasma-mass spectrometry. The work carried out demonstrates that pulsed rf-GD-OES is a promising tool for the fast analytical characterization of nanocomposite films. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Degradation of phenol and Cr (VI) wastewater with contact glow discharge electrolysis method and the addition of Fe2+

    Science.gov (United States)

    Kurniawan, Raden Ridzki Aditya; Saksono, Nelson

    2017-11-01

    Phenol and Cr (VI) are an organic waste and dangerous heavy metals which generated from a wide variety of industrial processes such as textiles, paints, dyes, and others. For that reason, we need effective waste treatment technologies, one of them is Contact Glow Discharge Electrolysis (CGDE). This method produce reactive species such as radical hidroxyl so as to be able to degradate phenol and Cr(VI) wastewater effectively. This research aims to obtain the effect of Fe 2+ and air bubbles in degradation of phenol and Cr (VI) waste simultaneously. Waste degradation is measured its absorbance with UV-Vis spectrophotometer. In the conditions of 600 Volt voltage, Na2SO4 0.02 M, anode depth of 1.5 cm, the addition of Fe2+ 40 ppm and the addition of air bubbles for 30 minutes was obtained a percentage degradation of phenol 99.47%, Cr (VI) 76.75% and specific energy of 344.473 kJ / mmol.

  1. A Critical Review of Published Data on the Gas Temperature and the Electron Density in the Electrolyte Cathode Atmospheric Glow Discharges

    Directory of Open Access Journals (Sweden)

    Tamás Cserfalvi

    2012-05-01

    Full Text Available Electrolyte Cathode Discharge (ELCAD spectrometry, a novel sensitive multielement direct analytical method for metal traces in aqueous solutions, was introduced in 1993 as a new sensing principle. Since then several works have tried to develop an operational mechanism for this exotic atmospheric glow plasma technique, however these attempts cannot be combined into a valid model description. In this review we summarize the conceptual and technical problems we found in this upcoming research field of direct sensors. The TG gas temperature and the ne electron density values published up to now for ELCAD are very confusing. These data were evaluated by three conditions. The first is the gas composition of the ELCAD plasma, since TG was determined from the emitted intensity of the N2 and OH bands. Secondly, since the ELCAD is an atmospheric glow discharge, thus, the obtained TG has to be close to the Te electron temperature. This can be used for the mutual validation of the received temperature data. Thirdly, as a consequence of the second condition, the values of TG and ne have to agree with the Engel-Brown approximation of the Saha-equation related to weakly ionized glow discharge plasmas. Application of non-adequate experimental methods and theoretical treatment leads to unreliable descriptions which cannot be used to optimize the detector performance.

  2. Secondary electron emission and glow discharge properties of 12CaO·7Al2O3 electride for fluorescent lamp applications

    Science.gov (United States)

    Watanabe, Satoru; Watanabe, Toshinari; Ito, Kazuhiro; Miyakawa, Naomichi; Ito, Setsuro; Hosono, Hideo; Mikoshiba, Shigeo

    2011-06-01

    12CaO·7Al2O3 electride, a sub-nanoporous compound having a work function of 2.4 eV, was examined as a candidate cathode material in fluorescent lamps. The electron emission yield was higher and the discharge voltage was lower for 12CaO·7Al2O3 than for existing cathode materials such as Ni, Mo or W; therefore, the energy consumption of the fluorescent lamps can be improved using 12CaO·7Al2O3 cathodes. Prototype glow-discharge lamps using 12CaO·7Al2O3 were constructed and exhibited reasonable durability.

  3. Secondary electron emission and glow discharge properties of 12CaO·7Al2O3 electride for fluorescent lamp applications.

    Science.gov (United States)

    Watanabe, Satoru; Watanabe, Toshinari; Ito, Kazuhiro; Miyakawa, Naomichi; Ito, Setsuro; Hosono, Hideo; Mikoshiba, Shigeo

    2011-06-01

    12CaO·7Al2O3 electride, a sub-nanoporous compound having a work function of 2.4 eV, was examined as a candidate cathode material in fluorescent lamps. The electron emission yield was higher and the discharge voltage was lower for 12CaO·7Al2O3 than for existing cathode materials such as Ni, Mo or W; therefore, the energy consumption of the fluorescent lamps can be improved using 12CaO·7Al2O3 cathodes. Prototype glow-discharge lamps using 12CaO·7Al2O3 were constructed and exhibited reasonable durability.

  4. Complementary low energy ion scattering and X-ray photoelectron spectroscopy characterization of polystyrene submitted to N{sub 2}/H{sub 2} glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Bonatto, F., E-mail: bonatto02@yahoo.com.br [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil); Rovani, S. [Universidade de Caxias do Sul, Caxias do Sul, Rio Grande do Sul 95070-560 (Brazil); Kaufmann, I.R.; Soares, G.V. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil); Baumvol, I.J.R. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil); Universidade de Caxias do Sul, Caxias do Sul, Rio Grande do Sul 95070-560 (Brazil); Krug, C. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil)

    2012-02-15

    Low energy ion scattering (LEIS) and X-ray photoelectron spectroscopy (XPS) were used to access the elemental composition and chemical bonding characteristics of polystyrene (PS) surfaces sequentially treated by corona and glow discharge (plasma) processing in N{sub 2}/H{sub 2} ambient. The latter has shown activity as suppressor of pathogenic Staphylococcus epidermidis biofilms. LEIS indicated that oxygen from the corona discharge process is progressively replaced by nitrogen at the PS surface. XPS shows C=N and N-C=O chemical groups as significant inhibitors of bacterial adhesion, suggesting application in medical devices.

  5. Transition rate diagrams — A new approach to the study of selective excitation processes: The spectrum of manganese in a Grimm-type glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, Zdeněk [LECO Instrumente Plzeň spol. s r.o., Plaská 66, 323 25 Plzeň (Czech Republic); Steers, Edward B.M. [London Metropolitan University, 166-220 Holloway Road, London N7 8DB (United Kingdom); Pickering, Juliet C. [Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom); Mushtaq, Sohail [London Metropolitan University, 166-220 Holloway Road, London N7 8DB (United Kingdom)

    2014-02-01

    The emission spectra of manganese observed using a Grimm-type glow discharge in pure argon, argon with 0.3% v/v hydrogen and pure neon were studied in order to identify major excitation and ionization processes of manganese in the plasma. A new procedure is proposed, in which each observed emission line is associated with the corresponding transition between different states of the Mn atom or Mn ion, and, by considering all the observed transitions from and into a specific state, a measure of the total rate is determined at which this state is radiatively populated and depopulated. These resulting population/depopulation rates are then plotted as function of level energy. Such plots, called here “transition rate diagrams”, show the role of individual states in the formation of the observed spectrum and can be used to identify possible selective excitation processes. Also, cascade excitation by radiative decay of higher excited states can be conveniently evaluated in this way. A detailed description of the observed Mn I and Mn II spectra is given for Ar, Ar–H{sub 2} and Ne plasmas and relevant excitation/ionization mechanisms are discussed. Matrix effects in analysis of manganese by glow discharge spectroscopy are discussed. A list of important Mn I and Mn II lines excited in the glow discharge plasma is given. - Highlights: • We measured GD-OES spectra of Mn in Ar, Ar(H) and Ne discharges. • We determined transition rate diagrams of Mn I and Mn II in these discharges. • Using those diagrams, we identified major excitation processes involved.

  6. MMW/THz imaging using upconversion to visible, based on glow discharge detector array and CCD camera

    Science.gov (United States)

    Aharon, Avihai; Rozban, Daniel; Abramovich, Amir; Yitzhaky, Yitzhak; Kopeika, Natan S.

    2017-10-01

    An inexpensive upconverting MMW/THz imaging method is suggested here. The method is based on glow discharge detector (GDD) and silicon photodiode or simple CCD/CMOS camera. The GDD was previously found to be an excellent room-temperature MMW radiation detector by measuring its electrical current. The GDD is very inexpensive and it is advantageous due to its wide dynamic range, broad spectral range, room temperature operation, immunity to high power radiation, and more. An upconversion method is demonstrated here, which is based on measuring the visual light emitting from the GDD rather than its electrical current. The experimental setup simulates a setup that composed of a GDD array, MMW source, and a basic CCD/CMOS camera. The visual light emitting from the GDD array is directed to the CCD/CMOS camera and the change in the GDD light is measured using image processing algorithms. The combination of CMOS camera and GDD focal plane arrays can yield a faster, more sensitive, and very inexpensive MMW/THz camera, eliminating the complexity of the electronic circuits and the internal electronic noise of the GDD. Furthermore, three dimensional imaging systems based on scanning prohibited real time operation of such imaging systems. This is easily solved and is economically feasible using a GDD array. This array will enable us to acquire information on distance and magnitude from all the GDD pixels in the array simultaneously. The 3D image can be obtained using methods like frequency modulation continuous wave (FMCW) direct chirp modulation, and measuring the time of flight (TOF).

  7. Characterization of thin film tandem solar cells by radiofrequency pulsed glow discharge - Time of flight mass spectrometry.

    Science.gov (United States)

    Fernandez, Beatriz; Lobo, Lara; Reininghaus, Nies; Pereiro, Rosario; Sanz-Medel, Alfredo

    2017-04-01

    Beside low production costs and the use of nontoxic and abundant raw materials, silicon based thin-film solar cells have the advantage to be built up as multi junction devices like tandem or triple junction solar cells. Silicon thin film modules made of tandem cells with hydrogenated amorphous silicon (a-Si:H) top cell and microcrystalline (μc) Si:H bottom cell are available on the market. In this work, the analytical potential of state-of-the art radiofrequency (rf) pulsed glow discharge (PGD) time of flight mass spectrometry (TOFMS) commercial instrumentation is investigated for depth profiling analysis of tandem-junctions solar cells on 2mm thick glass substrate with 1µm thick ZnO:Al. Depth profile characterization of two thin film tandem photovoltaic devices was compared using millisecond and sub-millisecond rf-PGD regimes, as well as the so-called "low mass mode" available in the commercial instrument used. Two procedures for sample preparation, namely using flat or rough cell substrates, were compared and the distribution of dopant elements (phosphorous, boron and germanium) was investigated in both cases. Experimental results obtained by rf-PGD-TOFMS as well as electrical measurements of the samples showed that a worse depth resolution of dopant elements in the silicon layers (e.g. distribution of boron in a thicker region that suggests a diffusion of this dopant in the coating of the sample) found using a rough sample substrate was related to a higher power conversion efficiency. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Gas chromatography coupled to tunable pulsed glow discharge time-of-flight mass spectrometry for environmental analysis.

    Science.gov (United States)

    Solà-Vázquez, Auristela; Lara-Gonzalo, Azucena; Costa-Fernández, José M; Pereiro, Rosario; Sanz-Medel, Alfredo

    2010-05-01

    A tuneable microsecond pulsed direct current glow discharge (GD)-time-of-flight mass spectrometer MS(TOF) developed in our laboratory was coupled to a gas chromatograph (GC) to obtain sequential collection of the mass spectra, at different temporal regimes occurring in the GD pulses, during elution of the analytes. The capabilities of this set-up were explored using a mixture of volatile organic compounds of environmental concern: BrClCH, Cl(3)CH, Cl(4)C, BrCl(2)CH, Br(2)ClCH, Br(3)CH. The experimental parameters of the GC-pulsed GD-MS(TOF) prototype were optimized in order to separate appropriately and analyze the six selected organic compounds, and two GC carrier gases, helium and nitrogen, were evaluated. Mass spectra for all analytes were obtained in the prepeak, plateau and afterpeak temporal regimes of the pulsed GD. Results showed that helium offered the best elemental sensitivity, while nitrogen provided higher signal intensities for fragments and molecular peaks. The analytical performance characteristics were also worked out for each analyte. Absolute detection limits obtained were in the order of ng. In a second step, headspace solid phase microextraction (HS SPME), as sample preparation and preconcentration technique, was evaluated for the quantification of the compounds under study, in order to achieve the required analytical sensitivity for trihalomethanes European Union (EU) environmental legislation. The analytical figures of merit obtained using the proposed methodology showed rather good detection limits (between 2 and 13 microg L(-1) depending on the analyte). In fact, the developed methodology met the EU legislation requirements (the maximum level permitted in tap water for the "total trihalomethanes" is set at 100 microg L(-1)). Real analysis of drinking water and river water were successfully carried out. To our knowledge this is the first application of GC-pulsed GD-MS(TOF) for the analysis of real samples. Its ability to provide elemental

  9. Determination of uranium isotope ratios using a liquid sampling atmospheric pressure glow discharge/Orbitrap mass spectrometer system.

    Science.gov (United States)

    Hoegg, Edward D; Marcus, R Kenneth; Koppenaal, David W; Irvahn, Jan; Hager, George J; Hart, Garret L

    2017-09-30

    The field of highly accurate and precise isotope ratio analysis, for use in nonproliferation, has been dominated by thermal ionization and inductively coupled plasma mass spectrometry. While these techniques are considered the gold standard for isotope ratio analysis, a downsized instrument capable of accurately and precisely measuring uranium (U) isotope ratios is desirable for field studies or in laboratories with limited infrastructure. The developed system interfaces the liquid sampling, an atmospheric pressure glow discharge (LS-APGD) ion source, with a high-resolution Exactive Orbitrap mass spectrometer. With this experimental setup certified U isotope standards and unknown samples were analyzed. The accuracy and precision of the system were then determined. The LS-APGD/Exactive instrument measured a certified reference material of natural U (235 U/238 U = 0.007261) with a 235 U/238 U ratio of 0.007065 and a % relative standard uncertainty of 0.082, meeting the International Target Values for the destructive analysis of U. In addition, when three unknowns were measured and these measurements were compared with the results from an ICP multi-collector instrument, there were no statistical differences between the two instruments. The LS-APGD/Orbitrap system, while still in the preliminary stages of development, offers highly accurate and precise isotope ratio results that suggest a potential paradigm shift in the world of isotope ratio analysis. Furthermore, the portability of the LS-APGD as an elemental ion source, combined with the small size and smaller operating demands of the Orbitrap, suggests that the instrumentation is capable of being field-deployable. Copyright © 2017 John Wiley & Sons, Ltd.

  10. A photon counting dynamic digital lock-in amplifier for background suppression in glow discharge atomic emission spectrometry

    Science.gov (United States)

    Gökmen, Ali; Ulgen, Ahmet; Yalçin, Şerife

    1996-01-01

    A photon counting dynamic digital lock-in amplifier, (PC-DDLIA), has been developed for the suppression of Ar lines in glow discharge lamp atomic emission spectrometry, (GDL-AES). The experimental set-up consists of a Grimm-type GDL, a prism-type scanning monochromator, photon counting electronics, an Apple Ile computer with an interface card and a computer controllable high voltage power supply. The photon counting electronics are designed to convert the photon pulses to logic pulses. A discriminator is used to reject pulses below a threshold level. The high voltage power supply is modulated with a square waveform generated from DAC and photon pulses are counted synchronously by the timer/counter chip, versatile interface adaptor (VIA-6522) on the interface card of computer. The data are analyzed in two steps. In the "learn mode", the GDL is modulated with a square waveform between 370 and 670 V and two spectra consisting of only Ar lines are obtained in a spectral window between 287.1 and 290.0 nm. A new modulation waveform is computed from these spectra which yields two overlapped spectra when the PC-DDLIA is scanned over the same spectral window. In the "analysis mode" of data acquisition, a target material with the analyte element(s) in it is used and the spectrometer is scanned with a dynamically varying rectangular waveform over the same spectral window. The net spectrum consists of pure atomic lines free from any Ar lines. The detection limit for the determination of Si (288.2 nm) in the presence of interfering Ar lines (288.1 and 288.4 nm) is found to be 0.083%, whereas suppression of Ar lines over the same spectral window lowers the detection limit to 0.013%.

  11. Etching of UO2 in NF3 RF Plasma Glow Discharge

    Energy Technology Data Exchange (ETDEWEB)

    Veilleux, John M. [Univ. of California, Berkeley, CA (United States)

    1999-08-01

    A series of room temperature, low pressure (10.8 to 40 Pa), low power (25 to 210 W) RF plasma glow discharge experiments with UO2 were conducted to demonstrate that plasma treatment is a viable method for decontaminating UO2 from stainless steel substrates. Experiments were conducted using NF3 gas to decontaminate depleted uranium dioxide from stainless-steel substrates. Depleted UO2 samples each containing 129.4 Bq were prepared from 100 microliter solutions of uranyl nitrate hexahydrate solution. The amorphous UO2 in the samples had a relatively low density of 4.8 gm/cm3. Counting of the depleted UO2 on the substrate following plasma immersion was performed using liquid scintillation counting with alpha/beta discrimination due to the presence of confounding beta emitting daughter products, 234Th and 234Pa. The alpha emission peak from each sample was integrated using a gaussian and first order polynomial fit to improve quantification. The uncertainties in the experimental measurement of the etched material were estimated at about ± 2%. Results demonstrated that UO2 can be completely removed from stainless-steel substrates after several minutes processing at under 200 W. At 180 W and 32.7 Pa gas pressure, over 99% of all UO2 in the samples was removed in just 17 minutes. The initial etch rate in the experiments ranged from 0.2 to 7.4 μm/min. Etching increased with the plasma absorbed power and feed gas pressure in the range of 10.8 to 40 Pa. A different pressure effect on UO2 etching was also noted below 50 W in which etching increased up to a maximum pressure, ~23 Pa, then decreased with further increases in pressure.

  12. Surface Oxide Net Charge of a Titanium Alloy; Comparison Between Effects of Treatment With Heat or Radiofrequency Plasma Glow Discharge

    Science.gov (United States)

    MacDonald, Daniel E.; Rapuano, Bruce E.; Schniepp, Hannes C.

    2010-01-01

    In the current study, we have compared the effects of heat and radiofrequency plasma glow discharge (RFGD) treatment of a Ti6Al4V alloy on the physico-chemical properties of the alloy’s surface oxide. Titanium alloy (Ti6Al4V) disks were passivated alone, heated to 600 °C, or RFGD plasma treated in pure oxygen. RFGD treatment did not alter the roughness, topography, elemental composition or thickness of the alloy’s surface oxide layer. In contrast, heat treatment altered oxide topography by creating a pattern of oxide elevations approximately 50–100 nm in diameter. These nanostructures exhibited a three-fold increase in roughness compared to untreated surfaces when RMS roughness was calculated after applying a spatial high-pass filter with a 200 nm cutoff wavelength. Heat treatment also produced a surface enrichment in aluminum and vanadium oxides. Both RFGD and heat treatment produced similar increases in oxide wettability. Atomic force microscopy (AFM) measurements of metal surface oxide net charge signified by a long range force of attraction to or repulsion from a (negatively charged) silicon nitride AFM probe were also obtained for all three experimental groups. Force measurements showed that the RFGD-treated Ti6Al4V samples demonstrated a higher net positive surface charge at pH values below 6 and a higher net negative surface charge at physiological pH (pH values between 7 and 8) compared to control and heat-treated samples These findings suggest that RFGD treatment of metallic implant materials can be used to study the role of negatively charged surface oxide functional groups in protein bioactivity, osteogenic cell behavior and osseointegration independently of oxide topography. PMID:20880672

  13. Correlation between reversion of signs of the electric field in the near-cathode plasma and anode fall potential in a short DC glow discharge

    Science.gov (United States)

    Prokhorova, E. I.; Kudryavtsev, A. A.; Platonov, A. A.; Slyshov, A. G.

    2017-07-01

    Relatively simple probe and optical experiments were performed, confirming the presence of two main scenarios for the formation of the longitudinal characteristics of a short (without positive column) glow discharge. 1. At low pressures, when there is a single point of sign reverse of the electric field at the maximum of the plasma density, the anode fall is negative and the magnitude of the anode fall is small, there is no ionization and the anode area is dark. 2. Upon an increase in pressure, two points of field reversal are to be expected, the sign of the anode fall is positive and the anode fall of potential is comparable to the gas ionization potential; therefore, the intensive ionization directly at the anode, which glows brightly, takes place.

  14. Study of the excitation mechanisms of the second positive system in the negative glow of a N{sub 2}-Ar discharge

    Energy Technology Data Exchange (ETDEWEB)

    Isola, L; Lopez, M; Gomez, B J, E-mail: isola@ifir-conicet.gov.ar [Instituto de Fisica Rosario (CONICET-UNR) 27 Febrero 210 Bis. (S2000EZP) Rosario (Argentina)

    2011-09-21

    In an Ar-N{sub 2} discharge, the high excitation transfer from Ar({sup 3}P{sub 2,0}) to N{sub 2} produces an overpopulation of the high rotational levels of the bands of the second positive system (SPS), and so the spectra interpretation is not straightforward. This paper presents a fit function for the SPS bands measured in Ar-N{sub 2}, which allows us to study the excitation process contributions to the N{sub 2}(C) level. The procedure was tested in the negative glow of a pulsed Ar-N{sub 2} discharge at a pressure of 2.5 Torr, for different mixture concentrations. In this discharge, through the fitting, it was possible to calculate the variation of the N{sub 2}(C) densities produced by different excitation processes as well as the variation of Ar metastable density.

  15. Difference in shape and width of Dα lines in the overvoltage and abnormal glow regimes of open discharge in narrow gap

    Science.gov (United States)

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

    2017-11-01

    Strong overvoltage discharges in a narrow gap between the solid cathode and grid anode (so called “open discharges”) are widely used for generation of the high-current electron beams. At low gas pressure (about 1 Torr) we revealed that discharge in the overvoltage gap stressed by stepwise voltage with amplitude up to 25 kV exhibits two regimes which follow one by one and generate the e-beams. The first of them produces the high-energy e-beam but the second generates the low-energy e-beam. The physical properties of these gas discharge regimes have been explored insufficiently. We have done the spectroscopic measurements of these regimes in D2 and found out that the overvoltage regime produces positive ions with high kinetic energy up to several keV but anomalous glow discharge forms the ions with energy of several tens of eV. The existence of high-energy ions in the overvoltage discharge provides a strong increase in the electron secondary emission from the cathode and possibly contributes to the ionization of the gas by fast ions. Our findings promote more insight into physics of the overvoltage discharge generating the high-current e-beams with energy up to 25 keV.

  16. Secondary electron emission and glow discharge properties of 12CaOcenterdot7Al2O3 electride for fluorescent lamp applications

    Directory of Open Access Journals (Sweden)

    Satoru Watanabe, Toshinari Watanabe, Kazuhiro Ito, Naomichi Miyakawa, Setsuro Ito, Hideo Hosono and Shigeo Mikoshiba

    2011-01-01

    Full Text Available 12CaOcenterdot7Al2O3 electride, a sub-nanoporous compound having a work function of 2.4 eV, was examined as a candidate cathode material in fluorescent lamps. The electron emission yield was higher and the discharge voltage was lower for 12CaOcenterdot7Al2O3 than for existing cathode materials such as Ni, Mo or W; therefore, the energy consumption of the fluorescent lamps can be improved using 12CaOcenterdot7Al2O3 cathodes. Prototype glow-discharge lamps using 12CaOcenterdot7Al2O3 were constructed and exhibited reasonable durability.

  17. Secondary electron emission and glow discharge properties of 12CaO{center_dot}7Al{sub 2}O{sub 3} electride for fluorescent lamp applications

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Satoru; Watanabe, Toshinari; Ito, Kazuhiro; Miyakawa, Naomichi; Ito, Setsuro [Research Center, Asahi Glass Co. Ltd, 1150 Hazawa-cho, Kanagawa-ku, Yokohama 221-8755 (Japan); Hosono, Hideo [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Mikoshiba, Shigeo, E-mail: satoru-webster@agc.com [Department of Electronic Engineering, The University of Electro-Communications, 1-5-1 Chofu, Tokyo 182-8585 (Japan)

    2011-06-15

    12CaO{center_dot}7Al{sub 2}O{sub 3} electride, a sub-nanoporous compound having a work function of 2.4 eV, was examined as a candidate cathode material in fluorescent lamps. The electron emission yield was higher and the discharge voltage was lower for 12CaO{center_dot}7Al{sub 2}O{sub 3} than for existing cathode materials such as Ni, Mo or W; therefore, the energy consumption of the fluorescent lamps can be improved using 12CaO{center_dot}7Al{sub 2}O{sub 3} cathodes. Prototype glow-discharge lamps using 12CaO{center_dot}7Al{sub 2}O{sub 3} were constructed and exhibited reasonable durability.

  18. Nanolayer biofilm coated on magnetic nanoparticles by using a dielectric barrier discharge glow plasma fluidized bed for immobilizing an antimicrobial peptide

    Science.gov (United States)

    Chen, Guangliang; Zhou, Mingyan; Chen, Shihua; Lv, Guohua; Yao, Juming

    2009-11-01

    Using the monomer of acrylic acid and the novel technique of using a dielectric barrier discharge glow plasma fluidized bed (GPFB), a nanolayer biofilm of polyacrylic acid (PAA) was uniformly coated on the surface of magnetic nickel nanoparticles (NPs). Transmission electron microscopy, Fourier transform infrared spectroscopy, and x-ray photoelectron spectroscopy, etc, were used to characterize the modified NPs. The thickness of the biofilm was about 2 nm when the NPs were treated using the GPFB once, and the discharging conditions affected the density of the carboxyl group obviously. The PAA acting as an adhesion layer was used to immobilize the antimicrobial peptide LL-37, to kill the bacteria of Escherichia coli (E. coli), and the results indicated that the modified nickel NPs immobilizing a certain concentration of LL-37 could kill the bacteria effectively.

  19. Study on the effect of hydrogen addition on the variation of plasma parameters of argon-oxygen magnetron glow discharge for synthesis of TiO2 films

    Directory of Open Access Journals (Sweden)

    Partha Saikia

    2016-04-01

    Full Text Available We report the effect of hydrogen addition on plasma parameters of argon-oxygen magnetron glow discharge plasma in the synthesis of H-doped TiO2 films. The parameters of the hydrogen-added Ar/O2 plasma influence the properties and the structural phases of the deposited TiO2 film. Therefore, the variation of plasma parameters such as electron temperature (Te, electron density (ne, ion density (ni, degree of ionization of Ar and degree of dissociation of H2 as a function of hydrogen content in the discharge is studied. Langmuir probe and Optical emission spectroscopy are used to characterize the plasma. On the basis of the different reactions in the gas phase of the magnetron discharge, the variation of plasma parameters and sputtering rate are explained. It is observed that the electron and heavy ion density decline with gradual addition of hydrogen in the discharge. Hydrogen addition significantly changes the degree of ionization of Ar which influences the structural phases of the TiO2 film.

  20. Influence of “Glow Discharge Plasma” as an External Stimulus on the Self-Assembly, Morphology and Binding Affinity of Gold Nanoparticle-Streptavidin Conjugates

    Science.gov (United States)

    Mamdouh, Wael; Li, Yingzhi; Shawky, Sherif M.; Azzazy, Hassan M. E.; Liu, Chang-Jun

    2012-01-01

    In this study, we investigate the influence of glow discharge plasma (GDP) on the self-assembly, morphology and binding affinity of streptavidin coated gold nanoparticles (Au-NP-SV) and biotinylated antibody (bAb) adsorbed on a highly oriented pyrolytic graphite (HOPG) substrate. Atomic force microscope (AFM) was used to image the pre- and post-GDP treated samples. The analysis of the AFM images showed a considerable change in the aggregation and morphology of Au-NP-conjugates after treatment with GDP. To our knowledge, this is the first report on using GDP to enhance and speed-up the aggregation (sintering) of adsorbed NP biomolecular conjugates. These results show a promising route that could be generalized for other NPs and their conjugates. It can also be considered as an alternative and cheap aggregation method for controlling the binding affinity of biomolecular species on different surfaces with interesting applications. PMID:22837648

  1. Influence of “Glow Discharge Plasma” as an External Stimulus on the Self-Assembly, Morphology and Binding Affinity of Gold Nanoparticle-Streptavidin Conjugates

    Directory of Open Access Journals (Sweden)

    Chang-Jun Liu

    2012-05-01

    Full Text Available In this study, we investigate the influence of glow discharge plasma (GDP on the self-assembly, morphology and binding affinity of streptavidin coated gold nanoparticles (Au-NP-SV and biotinylated antibody (bAb adsorbed on a highly oriented pyrolytic graphite (HOPG substrate. Atomic force microscope (AFM was used to image the pre- and post-GDP treated samples. The analysis of the AFM images showed a considerable change in the aggregation and morphology of Au-NP-conjugates after treatment with GDP. To our knowledge, this is the first report on using GDP to enhance and speed-up the aggregation (sintering of adsorbed NP biomolecular conjugates. These results show a promising route that could be generalized for other NPs and their conjugates. It can also be considered as an alternative and cheap aggregation method for controlling the binding affinity of biomolecular species on different surfaces with interesting applications.

  2. Modeling of a DC glow discharge in a neon-xenon gas mixture at low pressure and with metastable atom densities

    Science.gov (United States)

    Bouchikhi, A.

    2017-09-01

    The physical properties of Ne-Xe DC glow discharges at low pressure are reported for a gap length of 1 cm for the first time in the literature. The model deals specifically with the first three moments of Boltzmann’s equation and includes the radiation processes and metastable atom densities. The spatio-temporal distributions of the electron and neon and xenon ion densities, the neon and xenon metastable atom densities, the electric potential and the electric field as well as the mean electron energy are presented at 1.5 Torr and 250 V. The current-voltage characteristic is shown at 3 Torr, and it is compared with previous work for pure neon gas. The model is validated theoretically and experimentally in the case of pure gas.

  3. 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.

  4. 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.

  5. Deviation from Boltzmann distribution in excited energy levels of singly-ionized iron in an argon glow discharge plasma for atomic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lei; Kashiwakura, Shunsuke; Wagatsuma, Kazuaki, E-mail: wagatuma@imr.tohoku.ac.jp

    2012-01-15

    A Boltzmann plot for many iron ionic lines having excitation energies of 4.7-9.1 eV was investigated in an argon glow discharge plasma when the discharge parameters, such as the voltage/current and the gas pressure, were varied. A Grimm-style radiation source was employed in a DC voltage range of 400-800 V at argon pressures of 400-930 Pa. The plot did not follow a linear relationship over a wide range of the excitation energy, but it yielded a normal Boltzmann distribution in the range of 4.7-5.8 eV and a large overpopulation in higher-lying excitation levels of iron ion. A probable reason for this phenomenon is that excitations for higher excited energy levels of iron ion would be predominantly caused by non-thermal collisions with argon species, the internal energy of which is received by iron atoms for the ionization. Particular intense ionic lines, which gave a maximum peak of the Boltzmann plot, were observed at an excitation energy of ca. 7.7 eV. They were the Fe II 257.297-nm and the Fe II 258.111-nm lines, derived from the 3d{sup 5}4s4p {sup 6}P excited levels. The 3d{sup 5}4s4p {sup 6}P excited levels can be highly populated through a resonance charge transfer from the ground state of argon ion, because of good matching in the excitation energy as well as the conservation of the total spin before and after the collision. An enhancement factor of the emission intensity for various Fe II lines could be obtained from a deviation from the normal Boltzmann plot, which comprised the emission lines of 4.7-5.8 eV. It would roughly correspond to a contribution of the charge transfer excitation to the excited levels of iron ion, suggesting that the charge-transfer collision could elevate the number density of the corresponding excited levels by a factor of ca.10{sup 4}. The Boltzmann plots give important information on the reason why a variety of iron ionic lines can be emitted from glow discharge plasmas.

  6. Depth-profile analysis of thermoelectric layers on Si wafers by pulsed r.f. glow discharge time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Reinsberg, K.-G. [Institute for Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, D-20146 Hamburg (Germany); Schumacher, C. [Institute for Applied Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Tempez, A. [HORIBA Jobin Yvon, 16-18 rue du Canal, F-91160 Longjumeau (France); Nielsch, K. [Institute for Applied Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Broekaert, J.A.C., E-mail: jose.broekaert@chemie.uni-hamburg.de [Institute for Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, D-20146 Hamburg (Germany)

    2012-10-15

    In this work the depth-profile analysis of thermoelectric layers deposited on Au and Cr covered Si wafers with the aid of pulsed radiofrequency glow discharge time-of-flight mass spectrometry (pulsed RF-GD-TOFMS also called plasma profiling TOFMS (PP-TOFMS Trade-Mark-Sign )) is described. For thermoelectric materials the depth resolutions obtained with both PP-TOFMS and secondary ion mass spectrometry (SIMS) are shown to be well comparable and in the order of the roughness of the corresponding layers (between 20 and 3700 nm). With both methods a direct solid analysis without any preparation steps is possible. In addition, the analysis of the samples with PP-TOFMS proved to be faster by a factor of 26 compared to SIMS, as sputtering rates were found to be 80 nm s{sup -1} and 3 nm s{sup -1}, respectively. For the analyzed samples the results of PP-TOFMS and SIMS show that a homogeneous deposition was obtained. Quantitative results for all samples could also be obtained directly by PP-TOFMS when the stoichiometry of one sample was determined beforehand for instance by inductively coupled plasma optical emission spectrometry (ICP-OES) and scanning electron microscopy energy dispersive X-ray fluorescence spectrometry (SEM-EDX). For Bi{sub 2}Te{sub 3} the standard deviation for the main component concentrations within one sample then is found to be between 1.1% and 1.9% and it is 3.6% from sample to sample. For Sb{sub 2}Te{sub 3} the values within one sample are from 1.7% to 4.2% and from sample to sample 5.3%, respectively. - Highlights: Black-Right-Pointing-Pointer Depth resolution in sub micrometer size by glow discharge mass spectrometry. Black-Right-Pointing-Pointer Bi and Sb telluride layers composition with GD-TOF-MS, ICP-OES and SEM-EDX agree. Black-Right-Pointing-Pointer Homogeneities of layers measured with GD-TOF-MS and SIMS agree.

  7. Investigation on the erosion/deposition processes in the ITER-like wall divertor at JET using glow discharge optical emission spectrometry technique

    Science.gov (United States)

    Ruset, C.; Grigore, E.; Luculescu, C.; Tiseanu, I.; Likonen, J.; Mayer, M.; Rubel, M.; Matthews, G. F.; contributors, JET

    2016-02-01

    As a complementary method to Rutherford back scattering (RBS), glow discharge optical emission spectrometry (GDOES) was used to investigate the depth profiles of W, Mo, Be, O and C concentrations into marker coatings (CFC/Mo/W/Mo/W) and the substrate of divertor tiles up to a depth of about 100 μm. A number of 10 samples cored from particular areas of the divertor tiles were analyzed. The results presented in this paper are valid only for those areas and they cannot be extrapolated to the entire tile. Significant deposition of Be was measured on Tile 3 (near to the top), Tile 6 (at about 40 mm from the innermost edge) and especially on Tile 0 (HFGC). Preliminary experiments seem to indicate a penetration of Be through the pores and imperfections of CFC material up to a depth of 100 μm in some cases. No erosion and a thin layer of Be (<1 μm) was detected on Tiles 4, 7 and 8. On Tile 1 no erosion was found at about 1/3 from bottom.

  8. One-step preparation of nanostructured martite catalyst and graphite electrode by glow discharge plasma for heterogeneous electro-Fenton like process.

    Science.gov (United States)

    Khataee, Alireza; Sajjadi, Saeed; Hasanzadeh, Aliyeh; Vahid, Behrouz; Joo, Sang Woo

    2017-09-01

    Natural Martite ore particles and graphite were modified by alternating current (AC) glow discharge plasma to form nanostructured catalyst and cathode electrode for using in the heterogeneous-electro Fenton-like (Het-EF-like) process. The performance of the plasma-treated martite (PTM) and graphite electrode (PTGE) was studied for the treatment of paraquat herbicide in a batch system. 85.78% degradation efficiency for 20 mg L -1 paraquat was achieved in the modified process under desired operational conditions (i.e. current intensity of 300 mA, catalyst amount of 1 g L -1 , pH = 6, and background electrolyte (Na 2 SO 4 ) concentration of 0.05 mol L -1 ) which was higher than the 41.03% for the unmodified one after 150 min of treatment. The ecofriendly modification of the martite particles and the graphite electrode, no chemical needed, low leached iron and milder operational pH were the main privileges of plasma utilization. Moreover, the degradation efficiency through the process was not declined after five repeated cycles at the optimized conditions, which proved the stability of the nanostructured PTM and PTGE in the long-term usage. The archived results exhibit this method is the first example of high efficient, cost-effective, and environment-friendly method for generation of nanostructured samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Hydrogen retention studies on lithiated tungsten exposed to glow discharge plasmas under varying lithiation environments using Thermal Desorption Spectroscopy and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Castro, A. de, E-mail: alfonso.decastro@ciemat.es [Fusion National Laboratory-CIEMAT, Av Complutense 40, 28040 Madrid (Spain); Valson, P. [Max-Planck-Institut für Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald (Germany); Tabarés, F.L. [Fusion National Laboratory-CIEMAT, Av Complutense 40, 28040 Madrid (Spain)

    2017-04-15

    For the design of a Fusion Reactor based on a liquid lithium divertor target and a tungsten first wall at high temperature, the interaction of the wall material with plasmas of significant lithium content must be assessed, as issues like fuel retention, tungsten embrittlement and enhanced sputtering may represent a showstopper for the selection of the first wall material compatible with the presence of liquid metal divertor. In this work we address this topic for the first time at the laboratory level, hot W samples (100 °C) have been exposed to Glow Discharges of H{sub 2} or Li-seeded H{sub 2} followed by in situ thermal desorption studies (TDS) of the uptake of H{sub 2} on the samples. Pure and pre-lithiated tungsten was investigated in order to evaluate the differential effect of Li ion implantation on H retention. Global particle balance was also used for the determination of trapped H into the full W wall of the plasma chamber. A factor of 3-4 lower retention was deduced for samples and main W wall exposed to H/Li plasma than that measured on pre-lithiated W.

  10. Evaluation of different strategies for quantitative depth profile analysis of Cu/NiCu layers and multilayers via pulsed glow discharge - Time of flight mass spectrometry

    Science.gov (United States)

    Muñiz, Rocío; Lobo, Lara; Németh, Katalin; Péter, László; Pereiro, Rosario

    2017-09-01

    There is still a lack of approaches for quantitative depth-profiling when dealing with glow discharges (GD) coupled to mass spectrometric detection. The purpose of this work is to develop quantification procedures using pulsed GD (PGD) - time of flight mass spectrometry. In particular, research was focused towards the depth profile analysis of Cu/NiCu nanolayers and multilayers electrodeposited on Si wafers. PGDs are characterized by three different regions due to the temporal application of power: prepeak, plateau and afterglow. This last region is the most sensitive and so it is convenient for quantitative analysis of minor components; however, major elements are often saturated, even at 30 W of applied radiofrequency power for these particular samples. For such cases, we have investigated two strategies based on a multimatrix calibration procedure: (i) using the afterglow region for all the sample components except for the major element (Cu) that was analyzed in the plateau, and (ii) using the afterglow region for all the elements measuring the ArCu signal instead of Cu. Seven homogeneous certified reference materials containing Si, Cr, Fe, Co, Ni and Cu have been used for quantification. Quantitative depth profiles obtained with these two strategies for samples containing 3 or 6 multilayers (of a few tens of nanometers each layer) were in agreement with the expected values, both in terms of thickness and composition of the layers.

  11. The Influence of CO2 Admixtures on the Product Composition in a Nitrogen-Methane Atmospheric Glow Discharge Used as a Prebiotic Atmosphere Mimic.

    Science.gov (United States)

    Mazankova, V; Torokova, L; Krcma, F; Mason, N J; Matejcik, S

    2016-11-01

    This work extends our previous experimental studies of the chemistry of Titan's atmosphere by atmospheric glow discharge. The Titan's atmosphere seems to be similarly to early Earth atmospheric composition. The exploration of Titan atmosphere was initiated by the exciting results of the Cassini-Huygens mission and obtained results increased the interest about prebiotic atmospheres. Present work is devoted to the role of CO2 in the prebiotic atmosphere chemistry. Most of the laboratory studies of such atmosphere were focused on the chemistry of N2 + CH4 mixtures. The present work is devoted to the study of the oxygenated volatile species in prebiotic atmosphere, specifically CO2 reactivity. CO2 was introduced to the standard N2 + CH4 mixture at different mixing ratio up to 5 % CH4 and 3 % CO2. The reaction products were characterized by FTIR spectroscopy. This work shows that CO2 modifies the composition of the gas phase with the detection of oxygenated compounds: CO and others oxides. There is a strong influence of CO2 on increasing concentration other products as cyanide (HCN) and ammonia (NH3).

  12. Isotope ratio characteristics and sensitivity for uranium determinations using a liquid sampling-atmospheric pressure glow discharge ion source coupled to an Orbitrap mass analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Hoegg, Edward D.; Barinaga, Charles J.; Hager, George J.; Hart, Garret L.; Koppenaal, David W.; Marcus, R. Kenneth

    2016-01-01

    Abstract The continued development of the liquid sampling-atmospheric pressure glow discharge (LS-APGD) microplasma as an ion source for diverse, elemental/isotopic analysis applications continues. To this end, characterization of the capabilities in performing precise and accurate isotope ratio (IR) determinations is essential. Based on past experience with the Thermo Exactive Orbitrap mass analyzer, the LS-APGD was interfaced with this instrument for these tests. While the Orbitrap platform has demonstrated excellent mass resolution and accuracy in “organic” mass spectrometry (MS) applications, work using an Orbitrap for IR analysis is very sparse. These efforts build off previous work in this coupling, where the importance of a few of the LS-APGD discharge parameters and Orbitrap data acquisition methods on IR precision and accuracy were probed. Presented here are the results of a study that evaluated the analytical precision for natural uranium sample (assumed 235U/238U = 0.0072) determinations. The instrumental parameters evaluated include the number of microscans and scans making up a data acquisition set, uranium concentration/signal level, sample make-up, and Fourier transform digitization window. Ultimately, a precision of 0.41% relative standard deviation (RSD) can be achieved for a single determination, with a reproducibility of 1.63 %RSD over 10 separate analytical measurements. A preliminary study of matrix effects on IR measurements of U is presented, highlighting the importance of pre-mass selection before injection into the Orbitrap. The analytical system sensitivity is suggested with the ability to produce a calibration function having an R2 value of >0.99 over a range of 4 orders of magnitude of concentration (~1 – 1000 ng mL-1). These efforts demonstrate the very promising pairing of the LS-APGD ionization source and the Orbitrap, pointing as well to definitive paths forward to better utilize both components in high quality isotope ratio

  13. Rydberg gas theory of a glow discharge plasma: III. Formation, occupied state distributions, free energy, and kinetic control.

    Science.gov (United States)

    Mason, Rod S; Douglas, Peter

    2010-04-21

    It has been suggested that Rydberg gas atoms are involved in conducting electricity through a steady state flowing afterglow (FAG) discharge plasma (R. S. Mason, D. J. Mitchell and P. M. Dickinson, Phys. Chem. Chem. Phys., 2010, DOI: ). From known properties of Rydberg atoms, a statistical model is developed here to find the distribution of levels (principal quantum number n) occupied in such a hypothetical Rydberg gas. It behaves non-ideally at positive column plasma densities, predicting 30 states are very long-lived and almost completely separated from the low n states by the low probability of intermediate levels. The effects of Rydberg gas (N(R)) and free charge densities are examined. The gas can exist in a deep free energy well (> 120 kJ mol(-1) below ionisation level when 10(10) collision and deceleration at the opposite NG-Positive Column (PC) plasma boundary. The atoms become stabilized after passing into the PC, by collisionally induced (nlm) mixing of states and the removal of free charge by charge transfer (and hence the passage of electric current through the Rydberg gas). The coupling of Rydberg states with the ionization continuum is poor; therefore, if the rate of their charge transfer is greater than that of their ionization, the Rydberg gas will remain relatively charge free and hence stable when it is conducting a current. When applied to the FAG plasma, the model provides a self-consistent interpretive framework for all its electrical, mass spectrometric and chemical behaviour. The effect on the optical spectroscopy of these plasmas is considered briefly.

  14. Influence of Nitrided Layer on The Properties of Carbon Coatings Produced on X105CrMo17 Steel Under DC Glow-Discharge Conditions

    Directory of Open Access Journals (Sweden)

    Tomasz BOROWSKI

    2016-09-01

    Full Text Available In most cases, machine components, which come in contact with each other, are made of steel. Common steel types include 100Cr6 and X105CrMo17 are widely used in rolling bearings, which are subjected to high static loads. However, more and more sophisticated structural applications require increasingly better performance from steel. The most popular methods for improving the properties of steel is carburisation or nitriding. Unfortunately, when very high surface properties of steel are required, this treatment may be insufficient. Improvement of tribological properties can be achieved by increasing the hardness of the surface, reducing roughness or reducing the coefficient of friction. The formation of composite layers on steel, consisting of a hard nitride diffusion layer and an external carbon coating with a low coefficient of friction, seems to be a prospect with significant potential. The article describes composite layers produced on X105CrMo17 steel and defines their morphology, surface roughness and their functional properties such as: resistance to friction-induced wear, coefficient of friction and corrosion resistance. The layers have been formed at a temperature of 370°C in successive processes of: nitriding in low-temperature plasma followed by deposition of a carbon coating under DC glow-discharge conditions. An evaluation was also made of the impact of the nitrided layers on the properties and morphology of the carbon coatings formed by comparing them to coatings formed on non-nitrided X105CrMo17 steel substrates. A study of the surface topography, adhesion, resistance to friction-induced wear and corrosion shows the significant importance of the substrate type the carbon coatings are formed on.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.7532

  15. Determination of Hg{sup 2+} by on-line separation and pre-concentration with atmospheric-pressure solution-cathode glow discharge atomic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qing [Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 200050 (China); Zhang, Zhen [Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 200050 (China); School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Wang, Zheng, E-mail: wangzheng@mail.sic.ac.cn [Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 200050 (China)

    2014-10-03

    Highlights: • A modified SBA-15 mesoporous silica (SH-SBA-15) was synthesized as a sorbent. • On-line SPE combined with SCGD-AES based on FIA was used to detect Hg{sup 2+} firstly. • A simple, low-cost Hg{sup 2+} analysis in a complex matrix was established. • The sensitive detection of Hg{sup 2+} was achieved with a detection limit of 0.75 μg L{sup −1}. - Abstract: A simple and sensitive method to determine Hg{sup 2+} was developed by combining solution-cathode glow discharge atomic emission spectrometry (SCGD-AES) with flow injection (FI) based on on-line solid-phase extraction (SPE). We synthesized L-cysteine-modified mesoporous silica and packed it in an SPE microcolumn, which was experimentally determined to possess a good mercury adsorption capacity. An enrichment factor of 42 was achieved under optimized Hg{sup 2+} elution conditions, namely, an FI flow rate of 2.0 mL min{sup −1} and an eluent comprised of 10% thiourea in 0.2 mol L{sup −1} HNO{sub 3}. The detection limit of FI–SCGD-AES was determined to be 0.75 μg L{sup −1}, and the precision of the 11 replicate Hg{sup 2+} measurements was 0.86% at a concentration of 100 μg L{sup −1}. The proposed method was validated by determining Hg{sup 2+} in certified reference materials such as human hair (GBW09101b) and stream sediment (GBW07310)

  16. Isotope dilution mass spectrometry for quantitative elemental analysis of powdered samples by radiofrequency pulsed glow discharge time of flight mass spectrometry.

    Science.gov (United States)

    Alvarez-Toral, Aitor; Fernandez, Beatriz; Malherbe, Julien; Claverie, Fanny; Molloy, John L; Pereiro, Rosario; Sanz-Medel, Alfredo

    2013-10-15

    In recent years particular effort is being devoted to the development of pulsed glow discharges (PGDs) for mass spectrometry because this powering operation mode could offer important ionization analytical advantages. However, the capabilities of radiofrequency (RF) PGD coupled to a time of flight mass spectrometry (ToFMS) for accurate isotope ratio measurements have not been demonstrated yet. This work is focused on investigating different time positions along the pulse profile for the accurate measurement of isotope ratios. As a result, a method has been developed for the direct and simultaneous multielement determination of trace elements in powdered geological samples by RF-PGD-ToFMS in combination with isotope dilution mass spectrometry (IDMS) as an absolute measurement method directly traceable to the International System of Units. Optimized operating conditions were 70 W of applied radiofrequency power, 250 Pa of pressure, 2 ms of pulse width and 4 ms of pulse period, being argon the plasma gas used. To homogeneously distribute the added isotopically-enriched standards, lithium borate fusion of powdered solid samples was used as sample preparation approach. In this way, Cu, Zn, Ba and Pb were successfully determined by RF-PGD-ToF(IDMS) in two NIST Standard Reference Materials (SRM 2586 and SRM 2780) representing two different matrices of geological interest (soil and rock samples). Cu, Zn, Ba and Pb concentrations determined by RF-PGD-ToF(IDMS) were well in agreement with the certified values at 95% confidence interval and precisions below 12% relative standard deviation were observed for three independent analyses. Elemental concentrations investigated were in the range of 81-5770 mg/kg, demonstrating the potential of RF-PGD-ToF(IDMS) for a sensitive, accurate and robust analysis of powdered samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Influence of operating parameters on surface properties of RF glow discharge oxygen plasma treated TiO{sub 2}/PET film for biomedical application

    Energy Technology Data Exchange (ETDEWEB)

    Pandiyaraj, K. Navaneetha, E-mail: dr.knpr@gmail.com [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L and T by pass, Chinniyam Palayam (post), Coimbatore 641062 (India); Deshmukh, R.R. [Department of Physics, Institute of Chemical Technology, Matunga, Mumbai 400 019 (India); Mahendiran, R. [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L and T by pass, Chinniyam Palayam (post), Coimbatore 641062 (India); Su, Pi-G [Department of Chemistry, Chinese Culture University, Taipei 111, Taiwan (China); Yassitepe, Emre; Shah, Ismat [Department of Physics and Astronomy, Department of Materials Science and Engineering, University of Delaware, 208 Dupont Hall, Newark (United States); Perni, Stefano [School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff (United Kingdom); Prokopovich, Polina [School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff (United Kingdom); Institute of Medical Engineering and Medical Physics, School of Engineering, Cardiff University (United Kingdom); Nadagouda, Mallikarjuna N., E-mail: Nadagouda.Mallikarjuna@epamail.epa.gov [The U.S. Environmental Protection Agency, ORD, NRMRL, WSWRD, 26W. Martin Luther King Drive, Cincinnati, OH 45268 (United States)

    2014-03-01

    In this paper, a thin transparent titania (TiO{sub 2}) film was coated on the surface of flexible poly(ethylene terephthalate) (PET) film using the sol–gel method. The surface properties of the obtained TiO{sub 2}/PET film were further improved by RF glow discharge oxygen plasma as a function of exposure time and discharge power. The changes in hydrophilicity of TiO{sub 2}/PET films were analyzed by contact angle measurements and surface energy. The influence of plasma on the surface of the TiO{sub 2}/PET films was analyzed by atomic force microscopy (AFM) as well as the change in chemical state and composition that were investigated by X-ray photo electron spectroscopy (XPS). The cytotoxicity of the TiO{sub 2}/PET films was analyzed using human osteoblast cells and the bacterial eradication behaviors of TiO{sub 2}/PET films were also evaluated against Staphylococcus bacteria. It was found that the surface roughness and incorporation of oxygen containing polar functional groups of the plasma treated TiO{sub 2}/PET films increased substantially as compared to the untreated one. Moreover the increased concentration of Ti{sup 3+} on the surface of plasma treated TiO{sub 2}/PET films was due to the transformation of chemical states (Ti{sup 4+} → Ti{sup 3+}). These morphological and chemical changes are responsible for enhanced hydrophilicity of the TiO{sub 2}/PET films. Furthermore, the plasma treated TiO{sub 2}/PET film exhibited no citotoxicity against osteoblast cells and antibacterial activity against Staphylococcus bacteria which can find application in manufacturing of biomedical devices. - Graphical abstract: Mechanism of plasma treatment on the surface of TiO{sub 2}/PET films. - Highlights: • Investigated the surface properties of TiO{sub 2}/PET films modified by O{sub 2} plasma • Studied the effect of operating parameters on surface properties of TiO{sub 2}/PET films • Mechanism of the plasma treatment on TiO{sub 2}/PET was clearly investigated.

  18. Rapid analysis of pesticide residues in drinking water samples by dispersive solid-phase extraction based on multiwalled carbon nanotubes and pulse glow discharge ion source ion mobility spectrometry.

    Science.gov (United States)

    Zou, Nan; Gu, Kejia; Liu, Shaowen; Hou, Yanbing; Zhang, Jialei; Xu, Xiang; Li, Xuesheng; Pan, Canping

    2016-03-01

    An analytical method based on dispersive solid-phase extraction with a multiwalled carbon nanotubes sorbent coupled with positive pulse glow discharge ion mobility spectrometry was developed for analysis of 30 pesticide residues in drinking water samples. Reduced ion mobilities and the mass-mobility correlation of 30 pesticides were measured. The pesticides were divided into five groups to verify the separation capability of pulse glow discharge in mobility spectrometry. The extraction conditions such as desorption solvent, ionic strength, conditions of adsorption and desorption, the amounts of multiwalled carbon nanotubes, and solution pH were optimized. The enrichment factors of pesticides were 5.4- to 48.7-fold (theoretical enrichment factor was 50-fold). The detection limits of pesticides were 0.01∼0.77 μg/kg. The linear range was 0.005-0.2 mg/L for pesticide standard solutions, with determination coefficients from 0.9616 to 0.9999. The method was applied for the analysis of practical and spiked drinking water samples. All results were confirmed by high-performance liquid chromatography with tandem mass spectrometry. The proposed method was proven to be a commendably rapid screening qualitative and semiquantitative technique for the analysis of pesticide residues in drinking water samples on site. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Diamond-like carbon film preparation using a high-repetition nanosecond pulsed glow discharge plasma at gas pressure of 1 kPa generated by a SiC-MOSFET inverter power supply

    Science.gov (United States)

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

    2017-10-01

    A high-repetition nanosecond pulsed glow discharge plasma at a gas pressure of 1 kPa was generated using a SiC-MOSFET inverter power supply for diamond-like carbon (DLC) film preparation. At a high repetition frequency above 50 kHz, the period of the nanosecond voltage pulse became shorter than the decay time of the afterglow plasma, and many ions and radicals remained in the gap space. The deposition rate was 0.1 µm/min, which was 5 times higher than that of a conventional plasma CVD process. An increase in hardness to 13 GPa and a decrease in hydrogen content in the DLC film were confirmed by increasing the repetition frequency to 200 kHz.

  20. On self-sustainment of DC discharges with gridded anode

    Science.gov (United States)

    Yuan, Chengxun; Yao, Jingfeng; Eliseev, S. I.; Bogdanov, E. A.; Kudryavtsev, A. A.; Zhou, Zhongxiang

    2017-10-01

    The paper presents results of numerical investigation of a large-volume plasma source based on a DC discharge with gridded anode. Geometry and configuration of the electrodes were chosen so as to ensure the formation of a cathode sheath, which would accelerate electrons up to high energies and inject them into the post-anode space and create plasma. Simulations were carried out using a hybrid model, and distributions of the main discharge parameters were obtained in a wide range of currents. At low currents, cathode sheath occupies whole interelectrode gap while plasma is formed in the post-anode space. It is shown that ions moving through the anode grid into the interelectrode gap cause reduction of discharge voltage when compared to the case of classical obstructed discharge with virtually closed anode grid. At higher currents, however, plasma is formed within the interlectrode gap as well, and ions moving from plasma in the post-anode space become trapped by reversed electric field. This essentially nullifies influence of the post-anode plasma on discharge properties.

  1. Secondary electron emission and glow discharge properties of 12CaOcenterdot7Al2O3 electride for fluorescent lamp applications

    National Research Council Canada - National Science Library

    Satoru Watanabe, Toshinari Watanabe, Kazuhiro Ito, Naomichi Miyakawa, Setsuro Ito, Hideo Hosono and Shigeo Mikoshiba

    2011-01-01

    ... of 2.4 eV, was examined as a candidate cathode material in fluorescent lamps. The electron emission yield was higher and the discharge voltage was lower for 12CaOcenterdot7Al2O3 than for existing cathode materials such as Ni, Mo or W...

  2. Effect of the percentage of reinforcement on the wear in the metal matrix composites sintered with abnormal glow discharge; Efecto del porcentaje de refuerzo frente al desgaste en compuestos de matriz metalica sinterizados con descarga luminiscente anormal

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Velasquez, S.; Pineda-Triana, Y.; Aguilar-Castro, Y.; Vera-Lopez, E.

    2016-05-01

    In this study an analysis of the behavior of dry wear coefficient of a Metal Matrix Composite (MMC) in 316 stainless steel reinforced with particles of titanium carbide (TiC) according to ASTM G 99 standards, in a pin-on-disk test. In this research it is tested the effect of the percentage of reinforcement in the MMC manufactured with 3, 6 y 9% (vol.) of TiC, in samples compacted at 800 MPa, generating different values of grain size, hardness and density, they are sintered with abnormal glow discharge, at a temperature of 1200 degree centigrade ±5 degree centigrade, with a protection atmosphere H{sub 2} - N{sub 2} and a permanence time of 30 minutes. According to the results obtained it is concluded that the best condition for the MMC manufacturing, in relation to the reinforcement percentage, is the one obtained when the mixture contains 6% of TiC compacted at 800 MPa. In these conditions, it was obtained: achieving smaller grain size, the greater hardness and the lowest coefficient of friction. In this respect, it was observed that the incorporation of the ceramic particles (TiC) in a matrix of austenitic steel (316) shows significant improvements in the resistance to the wear. (Author)

  3. Mechanisms of sustaining a radio-frequency atmospheric pressure planar discharge

    Science.gov (United States)

    Wang, Lei; Dinescu, Gheorghe; Deng, Xiaolong; Ionita, Eusebiu-Rosini; Leys, Christophe; Nikiforov, Anton Yu

    2017-07-01

    The time behavior of an atmospheric pressure planar discharge sustained in He gas was investigated experimentally and through two dimensional (2D) discharge simulation. The 30 mm long uniform α-mode discharge was observed at radio frequency (RF) input power below 35 W. The gas temperature of 375 ± 50 K in the discharge core was estimated by emission spectroscopy of OH(A-X) emission. A sheath region of about 100-150 μm width near both electrodes was observed during the whole RF cycle. However, there were differences in emission dynamics among various species detected in the discharge. OH(A) emission does not follow the RF voltage temporal variation. Strong He emission was always detected near the cathode, which was consistent with the 2D discharge simulation results. He-excited species production was found mainly due to the electron impact process. The simulation showed that both the electron and ion density vary from 1.88 × 1017 m-3 to 1.92 × 1017 m-3, and the electron temperature was about 1.85 eV in the plasma bulk. The ion temperature stayed close to the rotational temperature of OH radicals, and only increased near the sheath region to 0.65 eV. It was found that the mechanism of the sheath formation in atmospheric pressure discharge strongly correlates with the dynamics of the electron density and electron temperature variation in the gap, and the process is similar to low pressure RF capacitively coupled discharges. The high uniformity of the discharge and the upscale possibility to any desirable size are considered beneficial for industrial applications of the source, which is key for processes of thin coating deposition and polymer modification.

  4. Non-self-sustained electric discharge in oxygen gas mixtures: singlet delta oxygen production

    CERN Document Server

    Ionin, A A; Kotkov, A A; Kochetov, I V; Napartovich, A P; Seleznev, L V; Sinitsyn, D V; Hager, G D

    2003-01-01

    The possibility of obtaining a high specific input energy in an electron-beam sustained discharge ignited in oxygen gas mixtures O sub 2 : Ar : CO (or H sub 2) at the total gas pressures of 10-100 Torr was experimentally demonstrated. The specific input energy per molecular component exceeded approx 6 kJ l sup - sup 1 atm sup - sup 1 (150 kJ mol sup - sup 1) as a small amount of carbon monoxide was added into a gas mixture of oxygen and argon. It was theoretically demonstrated that one might expect to obtain a singlet delta oxygen yield of 25% exceeding its threshold value needed for an oxygen-iodine laser operation at room temperature, when maintaining a non-self-sustained discharge in oxygen gas mixtures with molecular additives CO, H sub 2 or D sub 2. The efficiency of singlet delta oxygen production can be as high as 40%.

  5. Micro glow plasma for localized nanostructural modification of carbon nanotube forest

    Energy Technology Data Exchange (ETDEWEB)

    Sarwar, Mirza Saquib us; Xiao, Zhiming; Saleh, Tanveer; Nojeh, Alireza; Takahata, Kenichi [University of British Columbia, Vancouver, British Columbia V6T 1Z4 (Canada)

    2016-08-22

    This paper reports the localized selective treatment of vertically aligned carbon nanotubes, or CNT forests, for radial size modification of the nanotubes through a micro-scale glow plasma established on the material. An atmospheric-pressure DC glow plasma is shown to be stably sustained on the surface of the CNT forest in argon using micromachined tungsten electrodes with diameters down to 100 μm. Experiments reveal thinning or thickening of the nanotubes under the micro glow depending on the process conditions including discharge current and process time. These thinning and thickening effects in the treated nanotubes are measured to be up to ∼30% and ∼300% in their diameter, respectively, under the tested conditions. The elemental and Raman analyses suggest that the treated region of the CNT forest is pure carbon and maintains a degree of crystallinity. The local plasma treatment process investigated may allow modification of material characteristics in different domains for targeted regions or patterns, potentially aiding custom design of micro-electro-mechanical systems and other emerging devices enabled by the CNT forest.

  6. Ways for accurate analysis of high purity materials using the glow discharge mass spectrometry (GD-MS); Wege zur genauen Charakterisierung hochreiner Materialien mit der Glimmentladungs-Massenspektrometrie (GD-MS)

    Energy Technology Data Exchange (ETDEWEB)

    Gusarova, Tamara

    2010-04-14

    The main aim of this work consists in the investigation, development and application of improved possibilities of accurate analysis of high purity materials using the solid sample technique of Glow Discharge Mass Spectrometry (GD-MS), as well as in the sensitivity enhancement of GD Optical Emission Spectrometry (GD-OES) by implicating the hollow cathode effect. The emphasis of the PhD thesis consists in the accurate quantification for GD-MS. As appropriate certified reference materials (CRMs) for calibration are lacking in most cases an accurate quantification especially for trace elements mass fractions at {mu}g kg{sup -1} level can often not be achieved. To overcome this problem and to expand the possibilities of modern GD-MS hereby, synthetic standards were applied for calibration of both high resolution GD-MS instruments ''VG 9000'' and ''Element GD''. The standards were prepared by doping of matrix powder with trace element standard solutions followed by drying and pressing the doped powder to compact pellets. With the quantification approach worked out and described here accurate analysis results with small uncertainties can be achieved for most elements of periodic table in almost every matrix composition. Furthermore direct traceability of the analytical results to the International System of Units (SI) is provided ensuring their higher metrological quality. Numerous additional systematic investigations concerning the preparation of the synthetic standards and their properties were carried out. The results of calibration of GD-MS instruments with synthetic standards for Co (Co-C), Cu, In, Fe and Zn matrices were checked by measuring CRMs. These results were also contrasted with those of other quantification approaches, as usually used in GD-MS routine. The results achieved with synthetic standards had the highest accuracy. The successful participation in the round robin test CCQM-P107 between international

  7. Achieving ultrahigh vacuum in an unbaked chamber with glow ...

    Indian Academy of Sciences (India)

    Glow discharge conditioning (GDC) has long been accepted as one of the basic wall conditioning techniques for achieving ultrahigh vacuum in an unbaked chamber. As a part of this fundamental experimental study, a test chamber has been fabricated from stainless steel 304 L with its inner surface electropolished on ...

  8. Generation of uniform atmospheric pressure argon glow plasma by ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 80; Issue 3. Generation of uniform atmospheric pressure argon glow plasma by dielectric barrier discharge. Raju Bhai Tyata Deepak Prasad Subedi Rajendra Shrestha Chiow San Wong. Research Articles Volume 80 Issue 3 March 2013 pp 507-517 ...

  9. Faecal coliform simulation on sewage discharge for an environmentally sustainable township in Medini Iskandar Johor Malaysia

    Science.gov (United States)

    Teh, Su Yean; Koh, Hock Lye; Lee, Elizabeth; Woo, Wing Thye; Tan, Wai Kiat

    2017-11-01

    The Medini Iskandar Development is a 2300-acre multi-purpose urban development comprising residential, commercial, educational, business and recreational areas. The developer applied to the Department of Environment (DOE) Johor in July 2008 for approval of the environmental impact assessment (EIA) report for the overall Medini development. A conditional approval of the EIA report was granted by the DOE subject to some conditions, one of which stipulated that sewage effluent from the centralized sewage treatment plant (STP) is not permitted to be discharged into Sungai Pendas. A suitable location for the discharge of sewage into the Selat Johor is to be identified, based on a hydraulic and water quality modelling investigation. This modelling investigation aims to assess the impact of the discharge of treated sewage effluent on the marine water quality and on aquatic life in the Selat Johor. The supplementary EIA report was submitted to the DOE. Approval was granted in December 2011 for the construction of the marine sewage outfall and its operations. This paper presents the sampling and simulation results for key hydraulic and environmental parameters suitable for sustaining acceptable faecal coliform criteria in Selat Johor. Simulation models used include WASP7 developed by USEPA and AQUASEA developed by Vatnaskil Consulting Engineers.

  10. Detection of surface glow related to spacecraft glow phenomena

    Science.gov (United States)

    Langer, W. D.; Cohen, S. A.; Manos, D. M.; Motley, R. W.; Ono, M.

    1986-01-01

    A source of low energy neutral atoms and molecules has been developed by using a biased limiter to scrape off and reflect neutralized ions from a toroidal plasma. Beams of nitrogen and nitrogen-oxygen mixtures with energies of 1 to 15 eV and fluxes greater than about 10 to the 14 per centimeter per second were directed onto target surfaces consisting of Z-302 and Z-306 paints. With the nitrogen beams, a glow due to beam-surface interactions was successfully detected. In addition, a volume glow effect due to beam-gas interactions was observed which may play a role in spacecraft glow.

  11. Sky Glow Modeling and Measurements

    Science.gov (United States)

    Davis, D.

    2004-05-01

    It is very helpful to be able to model the impact of artificial night lighting on sky glow and also to measure such sky glow in a quantitative way. Such information is needed to understand the sources of the major impacts on the sky glow and to be able to offer effective solutions. This paper will review the current work underway on both these fronts, at professional observatories, a program in the Tucson and Pima County area in Tucson, by the National Park Service, and by the International Dark-Sky Association.

  12. Cold starting of fluorescent lamps - part II: experiments on glow times and electrode damaging

    Science.gov (United States)

    Langer, Reinhard; Paul, Irina; Hilscher, Achim; Horn, Siegfried; Tidecks, Reinhard

    2017-01-01

    In the present work we present experiments on cold start and the resulting electrode damaging (reducing lamp life) of AC driven fluorescent lamps. The crucial parameter is the glow time, determined from time resolved measurements of lamp voltage and current. The relation between the energy consumed during glow phase and the glow time is studied. It turns out that there is no common threshold of energy until the glow-to-arc transition takes place, but strong energy input into the lamp yields short glow times. The transient behaviour from the glow to the arc regime is investigated and the stable operation points of the arc discharge are determined, yielding an arc discharge voltage-current characteristics of the lamp type investigated. The electrode damage is investigated as a function of the open source voltage and the ballast resistance. Subsequent cold starts lead to an increase of the glow time due to electrode damaging, i.e., the electrode damage accumulates. Different regeneration procedures and their effectiveness are compared. Regeneration burning turns out to be more effective than heating up the electrode. A criterion for avoiding high electrode damage is obtained, indicating that the average power during glow time should exceed 20 W.

  13. Study of short atmospheric pressure dc glow microdischarge in air

    Science.gov (United States)

    Kudryavtsev, Anatoly; Bogdanov, Eugene; Chirtsov, Alexander; Emelin, Sergey

    2011-10-01

    The results of experiments and simulations of short (without positive column) atmospheric pressure dc glow discharge in air are presented. We used metal steel electrodes with a gap of 5-100 microns. The experimental voltage-current characteristic's (VAC) have a constant or slightly increasing form at low gap. The most stable microdischarges were burning with a flat cathode and rounded anode, when the length of the discharge is automatically established near the minimum of the Paschen curve by changing their binding on the anode. In this case microdischarge was stable and it had growing VAC. For simulations we used 2D fluid model with kinetic description of electrons. We solved the balance equations for the vibrationally- and the electronically-excited states of a nitrogen and oxygen molecules; nitrogen and oxygen atoms; ozone molecule; and different nitrogen and oxygen ions with different plasmochemical reactions between them. Simulations predicted the main regions of the dc glow discharges including cathode and anode sheath and plasma of negative glow, Faraday dark space and transition region. Gas heating plays an important role in shaping the discharge profiles. The results of experiments and simulations of short (without positive column) atmospheric pressure dc glow discharge in air are presented. We used metal steel electrodes with a gap of 5-100 microns. The experimental voltage-current characteristic's (VAC) have a constant or slightly increasing form at low gap. The most stable microdischarges were burning with a flat cathode and rounded anode, when the length of the discharge is automatically established near the minimum of the Paschen curve by changing their binding on the anode. In this case microdischarge was stable and it had growing VAC. For simulations we used 2D fluid model with kinetic description of electrons. We solved the balance equations for the vibrationally- and the electronically-excited states of a nitrogen and oxygen molecules; nitrogen

  14. Triggering Excimer Lasers by Photoionization from Corona Discharges

    Science.gov (United States)

    Xiong, Zhongmin; Duffey, Thomas; Brown, Daniel; Kushner, Mark

    2009-10-01

    High repetition rate ArF (192 nm) excimer lasers are used for photolithography sources in microelectronics fabrication. In highly attaching gas mixtures, preionization is critical to obtaining stable, reproducible glow discharges. Photoionization from a separate corona discharge is one technique for preionization which triggers the subsequent electron avalanche between the main electrodes. Photoionization triggering of an ArF excimer laser sustained in multi-atmosphere Ne/Ar/F2/Xe gas mixtures has been investigated using a 2-dimensional plasma hydrodynamics model including radiation transport. Continuity equations for charged and neutral species, and Poisson's equation are solved coincident with the electron temperature with transport coefficients obtained from solutions of Boltzmann's equation. Photoionizing radiation is produced by a surface discharge which propagates along a corona-bar located adjacent to the discharge electrodes. The consequences of pulse power waveform, corona bar location, capacitance and gas mixture on uniformity, symmetry and gain of the avalanche discharge will be discussed.

  15. Plasma Glow Discharge as a Tool for Surface Modification of Catalytic Solid Oxides: A Case Study of La0.6Sr0.4Co0.2Fe0.8O3−δ Perovskite

    Directory of Open Access Journals (Sweden)

    Yanxiang Zhang

    2016-09-01

    Full Text Available Performance of solid oxide fuel cells (SOFCs is hindered by the sluggish catalytic kinetics on the surfaces of cathode materials. It has recently been reported that improved electrochemical activity of perovskite oxides can be obtained with the cations or the oxides of some metallic elements at the surface. Here, we used a cost-effective plasma glow charge method as a generic tool to deposit nano-size metallic particles onto the surface of SOFC materials. Ni nano-scale patterns were successfully coated on the La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF surface. The microstructure could be well controlled. The kinetics of oxygen exchange on the modified LSCF surface was promoted significantly, confirmed by electrical conductivity relaxation (ECR measurement.

  16. The influence of a transverse magnetic field on a subnormal glow ...

    Indian Academy of Sciences (India)

    Abstract. In subnormal glow discharge under d.c. excitation at different pressure in a varying transverse magnetic field (0 to 30 G) some measurements have been carried out for various initial average tube currents. The voltage across the discharge increases and average tube current and residual current decreases in the ...

  17. Laser sustained discharge nozzle apparatus for the production of an intense beam of high kinetic energy atomic species

    Science.gov (United States)

    Cross, Jon B.; Cremers, David A.

    1988-01-01

    Laser sustained discharge apparatus for the production of intense beams of high kinetic energy atomic species. A portion of the plasma resulting from a laser sustained continuous optical discharge which generates energetic atomic species from a gaseous source thereof is expanded through a nozzle into a region of low pressure. The expanded plasma contains a significant concentration of the high kinetic energy atomic species which may be used to investigate the interaction of surfaces therewith. In particular, O-atoms having velocities in excess of 3.5 km/s can be generated for the purpose of studying their interaction with materials in order to develop protective materials for spacecraft which are exposed to such energetic O-atoms during operation in low earth orbit.

  18. Spatiotemporally resolved characteristics of a gliding arc discharge in a turbulent air flow at atmospheric pressure

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas

    2017-01-01

    of the glow-type discharge is the same as that of the electronic power dissipated in the plasma column. The glow-type discharge can transfer into a spark discharge characterized by a sharp peak current of several amperes and a sudden increase of the brightness in the plasma column. Transitions can also......A gliding arc discharge was generated in a turbulent air flow at atmospheric pressure driven by a 35 kHz alternating current (AC) electric power. The spatiotemporally resolved characteristics of the gliding arc discharge, including glow-type discharges, spark-type discharges, short-cutting events...... be found to take place from spark-type discharges to glow-type discharges. Short-cutting events were often observed as the intermediate states formed during the spark-glow transition. Three different types of short-cutting events have been observed to generate new current paths between two plasma channel...

  19. Photo-triggering and secondary electron produced ionization in electric discharge ArF* excimer lasers

    Science.gov (United States)

    Xiong, Zhongmin; Kushner, Mark J.

    2011-10-01

    Electric discharge excimer lasers are sustained in multi-atmosphere attaching gas mixtures that are typically preionized to enable a reproducible, uniform glow, which maximizes optical quality and gain. This preionization is often accomplished using UV light produced by a corona discharge within the plasma cavity. To quantify the relationship between corona discharge properties and those of the laser discharge, the triggering of electron avalanche by preionizing UV light in an electric discharge-pumped ArF* excimer laser was numerically investigated using a two-dimensional model. The preionizing UV fluxes were generated by a corona-bar discharge driven by the same voltage pulse as the main discharge sustained in a multi-atmospheric Ne/Ar/Xe/F2 gas mixture. The resulting peak photo-electron density in the inter-electrode spacing is around 108 cm-3, and its distribution is biased toward the UV source. The preionization density increases with increasing dielectric constant and capacitance of the corona bar. The symmetry and uniformity of the discharge are, however, improved significantly once the main avalanche develops. In addition to bulk electron impact ionization, the ionization generated by sheath accelerated secondary electrons was found to be important in sustaining the discharge current at experimentally observed values. At peak current, the magnitude of the ionization by sheath accelerated electrons is comparable to that from bulk electron impact in the vicinity of the cathode.

  20. Glow Sticks: Spectra and Color Mixing

    Science.gov (United States)

    Birriel, Jennifer; Birriel, Ignacio

    2014-01-01

    Glow sticks are a popular Halloween staple familiar to most of our students. The production of light via a chemical reaction is called "chemiluminescence," and glow sticks are often used as demonstrations and experiments in the chemistry classroom to study reaction rates as a function of temperature. A black light can be used to…

  1. In-flight observation of long duration gamma-ray glows by aircraft

    Science.gov (United States)

    Kochkin, Pavlo; (Lex) van Deursen, A. P. J.; de Boer, Alte; Bardet, Michiel; Allasia, Cedric; Boissin, Jean Francois; Ostgaard, Nikolai

    2017-04-01

    The Gamma-Ray Glow is a long-lasting (several seconds to minutes) X- and gamma radiation presumably originated from high-electric field of thunderclouds. Such glows were previously observed by aircraft, balloons, and from the ground. When detected on ground with other particles, i.e. electrons and neutrons, they are usually called Thunderstorm Ground Enhancements (TGEs). Their measured spectra are often consistent with Relativistic Runaway Electron Avalanche (RREA) mechanism. That is why RREA is a commonly accepted explanation for their existence. The gamma-ray glows are observed to be interrupted by lightning discharge, which terminates the high-electric field region. In January 2016 an Airbus A340 factory test aircraft was performing intentional flights through thunderstorms over Northern Australia. The aircraft was equipped with a dedicated in-flight lightning detection system called ILDAS (http://ildas.nlr.nl). The system also contained two scintillation detectors each with 38x38 mm cylinder LaBr3 crystals. While being at 12 km altitude the system detected a gamma-ray flux enhancement 30 times the background counts. It lasted for 20 seconds and was abruptly terminated by a lightning flash. The flash hit the aircraft and its parameters were recorded with 10 ns sampling time including gamma radiation. Ground-based lightning detection network WWLLN detected 4 strikes in the nearby region, all in association with the same flash. The ILDAS system recorded the time-resolved spectrum of the glow. In 6 minutes, after making a U-turn, the aircraft passed the same glow region. Smaller gamma-ray enhancement was again detected. In this presentation we will show the mapped event timeline including airplane, gamma-ray glow, WWLLN, and cloud data. We will discuss the glow's properties, i.e. intensity and differential spectrum, and its possible origin. This result will also be compared to previously reported observations.

  2. Glow plasma trigger for electron cyclotron resonance ion sources.

    Science.gov (United States)

    Vodopianov, A V; Golubev, S V; Izotov, I V; Nikolaev, A G; Oks, E M; Savkin, K P; Yushkov, G Yu

    2010-02-01

    Electron cyclotron resonance ion sources (ECRISs) are particularly useful for nuclear, atomic, and high energy physics, as unique high current generators of multicharged ion beams. Plasmas of gas discharges in an open magnetic trap heated by pulsed (100 micros and longer) high power (100 kW and higher) high-frequency (greater than 37.5 GHz) microwaves of gyrotrons is promising in the field of research in the development of electron cyclotron resonance sources for high charge state ion beams. Reaching high ion charge states requires a decrease in gas pressure in the magnetic trap, but this method leads to increases in time, in which the microwave discharge develops. The gas breakdown and microwave discharge duration becomes greater than or equal to the microwave pulse duration when the pressure is decreased. This makes reaching the critical plasma density initiate an electron cyclotron resonance (ECR) discharge during pulse of microwave gyrotron radiation with gas pressure lower than a certain threshold. In order to reduce losses of microwave power, it is necessary to shorten the time of development of the ECR discharge. For fast triggering of ECR discharge under low pressure in an ECRIS, we initially propose to fill the magnetic trap with the plasmas of auxiliary pulsed discharges in crossed ExB fields. The glow plasma trigger of ECR based on a Penning or magnetron discharge has made it possible not only to fill the trap with plasma with density of 10(12) cm(-3), required for a rapid increase in plasma density and finally for ECR discharge ignition, but also to initially heat the plasma electrons to T(e) approximately = 20 eV.

  3. Sintering unalloyed titanium in DC electrical abnormal glow discharge

    Directory of Open Access Journals (Sweden)

    Allan Seeber

    2010-03-01

    Full Text Available Powder metallurgy is widely used in the manufacture of components that have complex geometry. The good dimensional control, reduction in manufacturing steps and operating costs which has favored the use of this technique for manufacturing of titanium alloys components. However, the high affinity of this material with oxygen hinders strongly the sintering process. For this, the sintering associated with plasma technology can be considered an alternative technique for the processing of this material. The strict control of sintering atmosphere performed at low pressures and the reactive species present in the plasma environment can help to improve the sintering of this material. The results presented in this paper show a good correlation between the parameters used for the compaction of the samples and the microstructure develop during the plasma sintering of samples. The microstructure of the plasma assisted samples is also affected by the particular configuration used in the plasma reactor.

  4. Sustain and address discharge characteristics of AC-PDP with MgO surface coated by MgO nano crystal powders.

    Science.gov (United States)

    Kim, J H; Park, C S; Park, H D; Tae, H S; Lee, S H

    2013-05-01

    This paper examined the sustain and address discharge characteristics of ac-PDPs with MgO surface coated by MgO nano crystal powders. The MgO nano crystal powder was deposited by about 5% on the MgO surface by using the spray method. To investigate the effects of the partial addition of MgO nano crystal powders on the sustain discharge as well as the address discharge, the luminance, IR spectra of 823, 828 nm, cathodoluminance, and firing voltage were measured with the measurement of the address delay times and wall voltage variation in the 42-inch ac-PDP module with a high Xe content of 17%. As a result, the statistical delay characteristics were improved considerably especially under the low panel temperature of -5 degrees C for the MgO surface with MgO nano crystal powder. However, both MgO surfaces with and without the MgO nano crystal powder showed almost similar sustain and address discharge characteristics except the statistical delay characteristics.

  5. The Glowing Pickle and Other Vegetables

    Directory of Open Access Journals (Sweden)

    Ryan Burns

    2009-06-01

    Full Text Available The phenomenon known as the glowing pickle was investigated. Voltages ranging from 80-140 Volts AC were placed across a variety of vegetable specimens, both fresh and soaked in several salt solutions. The glowing was caused by electric arcing across a steam-filled cavity in the specimen. The emission spectra showed lines indicating the presence of potassium and sodium ions in the fresh specimens. In the specimens soaked in salt solutions, emission spectra matching the salt ions were observed.

  6. Studying Townsend and glow modes in an atmospheric-pressure DBD using mass spectrometry

    Science.gov (United States)

    McKay, Kirsty; Donaghy, David; He, Feng; Bradley, James W.

    2018-01-01

    Ambient molecular beam mass spectrometry has been employed to examine the effects of the mode of operation and the excitation waveform on the ionic content of a helium-based atmospheric-pressure parallel plate dielectric barrier discharge. By applying 10 kHz microsecond voltage pulses with a nanosecond rise times and 10 kHz sinusoidal voltage waveforms, distinctly different glow and Townsend modes were produced, respectively. Results showed a significant difference in the dominant ion species between the two modes. In the Townsend mode, molecular oxygen ions, atomic oxygen anions and nitric oxide anions are the most abundant species, however, in the glow mode water clusters ions and hydrated nitric oxygen anions dominate. Several hypotheses are put forward to explain these differences, including low electron densities and energies in the Townsend mode, more efficient ionization of water molecules through penning ionization and charge exchange with other species in glow mode, and large temperature gradients due to the pulsed nature of the glow mode, leading to more favorable conditions for cluster formation.

  7. Mastectomy - discharge

    Science.gov (United States)

    Breast removal surgery - discharge; Nipple-sparing mastectomy - discharge; Total mastectomy - discharge; Simple mastectomy - discharge; Modified radical mastectomy - discharge; Breast cancer - mastectomy -discharge

  8. Effect of Glow-to-Arc Transition on Loss Mechanism of Ba Atoms from Electrode of Fluorescent Lamp

    Science.gov (United States)

    Ueda, Takashi; Samir, Ahmed; Egashira, Yuichi; Yamashita, Go; Shimada, Shozaburo; Yamagata, Yukihiko; Uchino, Kiichiro; Manabe, Yoshio

    2007-10-01

    The loss of Ba atoms from the electrode of a fluorescent lamp was measured while the lamp was operated in the glow and arc discharge modes at 60 Hz. A laser-induced fluorescence (LIF) technique was applied to the measurements of the temporal and spatial distributions of Ba atoms in the vicinity of the electrode. Ground-state (61S0) Ba atoms were excited to a 51P1 level by a frequency-doubled dye laser beam (350.1 nm), and the subsequent fluorescence (51P1-51D2, 582.6 nm) was detected. The temporal and spatial distributions of Ba atoms were found to be completely different in the two discharge modes. Temporally; in the arc discharge mode, the density of the Ba atoms was found to have two peaks, and the number of Ba atoms emitted in the anode half-cycle was about twofold larger than that emitted in the cathode half-cycle. In the glow discharge mode, the number of Ba atoms emitted in the anode half-cycle was found to be negligible compared with that emitted in the cathode half-cycle. Spatially; in the arc discharge mode, Ba atoms were found to be emitted mainly from the hot spot of the filament electrode. In the glow discharge mode, Ba atoms were found to be emitted from all parts of the filament electrodes homogeneously. The mechanism of Ba atom loss in both modes was discussed.

  9. Characterization of ultra-short pulsed discharge plasma for CVD processing. [Chemical Vapor Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, Akira (Toyohashi Univ. of Technology (Japan). Dept. of Ecological Engineering); Okazaki, Ken (Tokyo Inst. of Technology (Japan). Research Center for Carbon Recycling and Utilization); Takekoshi, Takashi (Mitsubishi Kasei Co., Okayama (Japan). Mizushima Works); Tobe, Ryoki (Anelva Corp., Tokyo (Japan). Research Development Center)

    Characteristics of pulsed discharge plasma of methane-hydrogen gas mixture and Ar gas have been studied for active control of plasma chemical vapor deposition (CVD) processing. Voltage-current characteristics, time-lag of the current pulse, and the photon emission intensity profile have been investigated using high-voltage pulses of 50-1000 ns duration. In such a pulse discharge, voltages much higher than those in a dc glow discharge can be applied without any plasma nonuniformity or arcing because voltage amplitude falls to zero before glow to arc transition. A current value of more than 10[sup 3] times those in a glow discharge can be established. Very high photon emission intensity from CH radicals and H ions have been observed near the anode in a pulsed plasma. This is different in dc plasma, where the negative glow region near the cathode is the brightest.

  10. Discharge creeping along the surface in the process for producing nanomaterials

    Science.gov (United States)

    Timerkaev, B. A.; Andreeva, A. A.; Sofronitskiy, A. O.

    2017-11-01

    In this paper, we propose a new principle of assembling carbon nanoparticles in the plasma of a glow discharge creeping along the surface. In this paper, it is shown that carbon nanoparticles (fullerenes and nanotubes), as well as light fractions of oil, can be produced by means of a glow discharge on the surface of the fuel oil. Single-walled carbon nanotubes of about 10 μm in length were obtained.

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

    Energy Technology Data Exchange (ETDEWEB)

    Baldanov, B. B., E-mail: baibat@mail.ru [Russian Academy of Sciences, Institute of Physical Material Science, Siberian Branch (Russian Federation)

    2016-01-15

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

  12. Hybrid simulation of electron energy distributions and plasma characteristics in pulsed RF CCP sustained in Ar and SiH4/Ar discharges

    Science.gov (United States)

    Wang, Xi-Feng; Jia, Wen-Zhu; Song, Yuan-Hong; Zhang, Ying-Ying; Dai, Zhong-Ling; Wang, You-Nian

    2017-11-01

    Pulsed-discharge plasmas offer great advantages in deposition of silicon-based films due to the fact that they can suppress cluster agglomeration, moderate the energy of bombarding ions, and prolong the species' diffusion time on the substrate. In this work, a one-dimensional fluid/Monte-Carlo hybrid model is applied to study pulse modulated radio-frequency (RF) plasmas sustained in capacitively coupled Ar and SiH4/Ar discharges. First, the electron energy distributions in pulsed Ar and SiH4/Ar plasmas have been investigated and compared under identical discharge-circuit conditions. The electron energy distribution function (EEDF) in Ar discharge exhibits a familiar bi-Maxwellian shape during the power-on phase of the pulse, while a more complex (resembling a multi-Maxwellian) distribution with extra inflection points at lower energies is observed in the case of the SiH4/Ar mixture. These features become more prominent with the increasing fraction of SiH4 in the gas mixture. The difference in the shape of the EEDF (which is pronounced inside the plasma but not in the RF sheath where electron heating occurs) is mainly attributed to the electron-impact excitations of SiH4. During the power-off phase of the pulse, the EEDFs in both Ar and SiH4/Ar discharges evolve into bi-Maxwellian shapes, with shrinking high energy tails. Furthermore, the parameter of ion species in the case of SiH4/Ar discharge is strongly modulated by pulsing. For positive ions, such as SiH3+ and Si2H4+ , the particle fluxes overshoot at the beginning of the power-on interval. Meanwhile, for negative ions such as SiH2- and SiH3- , density profiles observed between the electrodes are saddle-shaped due to the repulsion by the self-bias electric field as it builds up. During the power-off phase, the wall fluxes of SiH2- and SiH3- gradually increase, leading to a significant decrease in the net surface charge density on the driven electrode. Compared with ions, the density of SiH3 is poorly modulated

  13. A photometric model for predicting the sky glow of greenhouses

    NARCIS (Netherlands)

    Alferdinck, J.W.A.M.; Janssen, E.G.O.N.; Zonneveldt, L.; Ruigrok, J.

    2006-01-01

    many greenhouses use artificial light to grow plants. Part of this light escapes, scatters in the sky and causes sky glow. Residents in the vicinity complain about the absence of natural darkness. A light scatter model is developed in order to quantify the dose of the sky glow. The luminance of the

  14. Thermoluminescence glow curve involving any extent of retrapping ...

    Indian Academy of Sciences (India)

    considered to be the basic equations which have been used by various workers to explain the occurrence of TL glow curve [3]. Mechanisms inherent in systems involving first- order kinetics or monomolecular kinetics are supposed to be recombination dominant with negligible or zero retrapping. Intensity (I1) of the TL glow ...

  15. Generation of metallic arc spectrum of pumping discharge of XeCl laser; XeCl ekishima laser reiki hoden ni okeru arc iko to kinzoku supekutoru no hassei

    Energy Technology Data Exchange (ETDEWEB)

    Koike, H.; Yukimura, K. [Doshisha University, Kyoto (Japan)

    1997-12-20

    An arc generation of a long-pulse spiker-sustainer excimer laser with about 250ns of pulse width , is discussed by using time-varying spectroscopic method. First arcing occurs during a main discharge for laser excitation and shows XeII spectrum, while a glow-like discharge represents only XeI spectrum, the metallic spectrum such as Nil caused by vaporization of electrode material begins to appear just after the termination of the main discharge. Second arcing occurs after about 2{mu}s, which brings strong intensity of Nil spectrum. It means that the reignition arc might be produced in a metallic vapor that appears during the main discharge. Accordingly, it is concluded that the reignition arc is inherently metallic, which is different from the main arc with rare gas plasma. 9 refs., 9 figs.

  16. Acting green elicits a literal warm glow

    Science.gov (United States)

    Taufik, Danny; Bolderdijk, Jan Willem; Steg, Linda

    2015-01-01

    Environmental policies are often based on the assumption that people only act environmentally friendly if some extrinsic reward is implicated, usually money. We argue that people might also be motivated by intrinsic rewards: doing the right thing (such as acting environmentally friendly) elicits psychological rewards in the form of positive feelings, a phenomenon known as warm glow. Given the fact that people's psychological state may affect their thermal state, we expected that this warm glow could express itself quite literally: people who act environmentally friendly may perceive the temperature to be higher. In two studies, we found that people who learned they acted environmentally friendly perceived a higher temperature than people who learned they acted environmentally unfriendly. The underlying psychological mechanism pertains to the self-concept: learning you acted environmentally friendly signals to yourself that you are a good person. Together, our studies show that acting environmentally friendly can be psychologically rewarding, suggesting that appealing to intrinsic rewards can be an alternative way to encourage pro-environmental actions.

  17. Measurement of radiation and temperature of cathod spots in excimer laser discharge; Ekishima reza reiki hodennai ni fukumareru inkyoku kiten no kogakuteki kansoku to ondo no sokutei

    Energy Technology Data Exchange (ETDEWEB)

    Minamitani, Y.; Nakatani, H. [Mitsubishi Electric Corp., Tokyo (Japan)

    1996-08-20

    Excimer laser is used in various fields such as luminous source for steppers, annealing treatment, ablation process, nuclear fusion and so on. In this paper, the radiation timing and gas temperature of cathode spots, streamer discharges and glow discharges in KrF excimer are measured by observing the radiating spectra thereof. The following conclusions are obtained from the results of the present study. Cathode spots begin to radiate at about 20ns after the discharge initiation, then the first and second radiation peaks are observed respectively when the discharge current reversing after passing zero point and the reserved discharged current approaching zero point. Streamer discharge makes flashover between electrodes at the second radiation peak of cathode spots, while the glow discharges almost disappear when streamer discharges occurring. The temperatures of cathode spots and glow discharge as 5500K and 2600K respectively are almost constant and independent upon the discharging voltage of laser. 14 refs., 12 figs.

  18. Acute hospitalization and discharge outcome of neurologically intact trauma patients sustaining thoracolumbar vertebral fractures managed conservatively with thoracolumbosacral orthoses and physical therapy.

    Science.gov (United States)

    Melchiorre, P J

    1999-02-01

    To identify the acute hospital discharge functional status achieved and the amount of physical therapy (PT) and occupational therapy (OT) received by neurologically intact patients with thoracolumbar vertebral fractures managed only by bracing with a custom-molded thoracolumbosacral orthosis (TLSO). These patients would be expected to ambulate independently soon after receiving their TLSOs unless they had concomitant lower extremity injuries, but they may need assistance with lower extremity activities of daily living. Retrospective study. Urban, level I trauma center. Twenty-seven subjects who sustained one or more thoracolumbar fractures, were neurologically intact, and were managed nonoperatively with a custom-molded TLSO. Median time to TLSO arrival, start of PT, number of PT sessions, time to ambulate independently from admission, and length of stay (LOS). Median time to TLSO arrival was 2 days, start of PT was 4 days, number of PT sessions was one, time to ambulate independently from admission was 3(1/2) days, and LOS was 5 days. Subjects with lower extremity fractures required significantly (p TLSO ambulate independently after receiving one or two sessions of PT and can be discharged home on the same day of PT clearance. Patients with lower-extremity fractures need more PT to achieve independent ambulation. The consequences of a minority of these patients being evaluated and seen by OT are not fully known. Future research may be able to document the need for more OT services.

  19. Atmospheric-pressure glow plasma synthesis of plasmonic and photoluminescent zinc oxide nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Bilik, N., E-mail: bilik006@umn.edu, E-mail: kortshagen@umn.edu; Greenberg, B. L.; Yang, J.; Kortshagen, U. R., E-mail: bilik006@umn.edu, E-mail: kortshagen@umn.edu [Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Aydil, E. S. [Department of Chemical Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2016-06-28

    In this paper, we present a large-volume (non-micro) atmospheric pressure glow plasma capable of rapid, large-scale zinc oxide nanocrystal synthesis and deposition (up to 400 μg/min), whereas in the majority of the literature, nanoparticles are synthesized using micro-scale or filamentary plasmas. The reactor is an RF dielectric barrier discharge with a non-uniform gap spacing. This design encourages pre-ionization during the plasma breakdown, making the discharge uniform over a large volume. The produced zinc oxide nanocrystals typically have diameters ranging from 4 to 15 nm and exhibit photoluminescence at ≈550 nm and localized surface plasmon resonance at ≈1900 cm{sup −1} due to oxygen vacancies. The particle size can be tuned to a degree by varying the gas temperature and the precursor mixing ratio.

  20. Nanosecond Repetitively Pulsed Discharges in Air at Atmospheric Pressure -- Experiment and Theory of Regime Transitions

    Science.gov (United States)

    Pai, David; Lacoste, Deanna; Laux, Christophe

    2009-10-01

    In atmospheric pressure air preheated from 300 to 1000 K, the Nanosecond Repetitively Pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and inter-electrode gap distance) of each discharge regime. Notably, there is a minimum gap distance for the existence of the glow regime that increases with decreasing gas temperature. A theory is developed to describe the Corona-to-Glow (C-G) and Glow-to-Spark (G-S) transitions for NRP discharges. The C-G transition is shown to depend on the Avalanche-to-Streamer Transition (AST) as well as the electric field strength in the positive column. The G-S transition is due to the thermal ionization instability. The minimum gap distance for the existence of the glow regime can be understood by considering that the applied voltage of the AST must be lower than that of the thermal ionization instability. This is a previously unknown criterion for generating glow discharges, as it does not correspond to the Paschen minimum or to the Meek-Raether criterion.

  1. tgcd: An R package for analyzing thermoluminescence glow curves

    Directory of Open Access Journals (Sweden)

    Jun Peng

    2016-01-01

    Full Text Available Thermoluminescence (TL glow curves are widely used in dosimetric studies. Many commercial and free-distributed programs are used to deconvolute TL glow curves. This study introduces an open-source R package tgcd to conduct TL glow curve analysis, such as kinetic parameter estimation, glow peak simulation, and peak shape analysis. TL glow curves can be deconvoluted according to the general-order empirical expression or the semi-analytical expression derived from the one trap-one recombination center (OTOR model based on the Lambert W function by using a modified Levenberg–Marquardt algorithm from which any of the parameters can be constrained or fixed. The package provides an interactive environment to initialize parameters and offers an automated “trial-and-error” protocol to obtain optimal fit results. First-order, second-order, and general-order glow peaks (curves are simulated according to a number of simple kinetic models. The package was developed using a combination of Fortran and R programming languages to improve efficiency and flexibility.

  2. tgcd: An R package for analyzing thermoluminescence glow curves

    Science.gov (United States)

    Peng, Jun; Dong, ZhiBao; Han, FengQing

    Thermoluminescence (TL) glow curves are widely used in dosimetric studies. Many commercial and free-distributed programs are used to deconvolute TL glow curves. This study introduces an open-source R package tgcd to conduct TL glow curve analysis, such as kinetic parameter estimation, glow peak simulation, and peak shape analysis. TL glow curves can be deconvoluted according to the general-order empirical expression or the semi-analytical expression derived from the one trap-one recombination center (OTOR) model based on the Lambert W function by using a modified Levenberg-Marquardt algorithm from which any of the parameters can be constrained or fixed. The package provides an interactive environment to initialize parameters and offers an automated "trial-and-error" protocol to obtain optimal fit results. First-order, second-order, and general-order glow peaks (curves) are simulated according to a number of simple kinetic models. The package was developed using a combination of Fortran and R programming languages to improve efficiency and flexibility.

  3. Feedback model of secondary electron emission in DC gas discharge plasmas

    Science.gov (United States)

    Saravanan, ARUMUGAM; Prince, ALEX; Suraj, Kumar SINHA

    2018-01-01

    Feedback is said to exist in any amplifier when the fraction of output power in fed back as an input. Similarly, in gaseous discharge ions that incident on the cathode act as a natural feedback element to stabilize and self sustain the discharge. The present investigation is intended to emphasize the feedback nature of ions that emits secondary electrons (SEs) from the cathode surface in DC gas discharges. The average number of SEs emitted per incident ion and non ionic species (energetic neutrals, metastables and photons) which results from ion is defined as effective secondary electron emission coefficient (ESEEC,{γ }{{E}}). In this study, we derive an analytic expression that corroborates the relation between {γ }{{E}} and power influx by ion to the cathode based on the feedback theory of an amplifier. In addition, experimentally, we confirmed the typical positive feedback nature of SEE from the cathode in argon DC glow discharges. The experiment is done for three different cathode material of same dimension (tungsten (W), copper (Cu) and brass) under identical discharge conditions (pressure: 0.45 mbar, cathode bias: ‑600 V, discharge gab: 15 cm and operating gas: argon). Further, we found that the {γ }{{E}} value of these cathode material controls the amount of feedback power given by ions. The difference in feedback leads different final output i.e the power carried by ion at cathode ({P}{{i}}{\\prime }{| }{{C}}). The experimentally obtained value of {P}{{i}}{\\prime }{| }{{C}} is 4.28 W, 6.87 W and 9.26 W respectively for W, Cu and brass. In addition, the present investigation reveals that the amount of feedback power in a DC gas discharges not only affect the fraction of power fed back to the cathode but also the entire characteristics of the discharge.

  4. 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 ...

  5. Transition from symmetric discharge to asymmetric discharge in a short gap helium dielectric barrier discharge

    Science.gov (United States)

    Ning, Wenjun; Dai, Dong; Zhang, YuHui; Hao, Yanpeng; Li, Licheng

    2017-07-01

    The discharge dynamics of a 2.08 mm gap helium dielectric barrier discharge (DBD) are studied with a one-dimensional fluid model. By increasing the amplitude of a sinusoidal voltage source, it is observed that the discharge is symmetric at first and abruptly turns into an asymmetric state after passing a certain critical value. Compared with former publications dealing with relatively larger gap-distance DBD, our simulation results indicate some new discoveries. First, in both the symmetric and asymmetric states, every discharge event is fully developed from Townsend discharge to glow discharge, and the discharge current appears as a steep narrow pulse. Second, the residual positive column is always completely dissipated before the next break down; therefore, its influence on the symmetric-to-asymmetric transition can be eliminated. It is further revealed that the symmetric-to-asymmetric transition in the short-gap DBD is more delicate. A subtle phase shift is observed before the transition process. When the phase shift is further promoted with voltage rising, a discordance of the evolution paces between electron and ions occurs, which consequently leads to the formation of discharge asymmetry.

  6. Thermoluminescence study of the trapped charge at an alumina surface electrode in different dielectric barrier discharge regimes

    Energy Technology Data Exchange (ETDEWEB)

    Ambrico, P F; Ambrico, M; Dilecce, G; De Benedictis, S [Consiglio Nazionale delle Ricerche, Istituto di Metodologie Inorganiche e dei Plasmi UOS Bari-c/o Dipartimento di Chimica, Universita degli Studi di Bari ' Aldo Moro' , via Orabona, 4, 70126 Bari (Italy); Colaianni, A [Dipartimento di Geologia e Geofisica, Universita degli Studi di Bari ' Aldo Moro' , via Orabona, 4, 70126 Bari (Italy); Schiavulli, L, E-mail: paolofrancesco.ambrico@cnr.i [Dipartimento Interateneo di Fisica, Universita degli Studi di Bari ' Aldo Moro' , via Orabona, 4, 70126 Bari (Italy)

    2010-08-18

    In this study, the charge trapping effect in alumina dielectric surfaces has been deeply investigated by means of a dedicated dielectric barrier discharge apparatus in different discharge regimes and gas mixtures. This work further validates our previous findings in the case of air discharges in a filamentary regime. Long lasting charge trapping has been evidenced by ex situ thermoluminescence characterizations of alumina dielectric barrier plates exposed to a plasma. The density of trapped surface charges was found to be higher in the glow discharge with respect to pseudo-glow and filamentary regimes, and for all regimes the minimum trap activation temperature was 390 K and the trap energy was less than or around 1 eV. This implies that in the case of glow discharges a higher reservoir of electrons is present. Also, the effect was found to persist for several days after running the discharge.

  7. Characteristics of a propagating, self-pulsing, constricted ‘γ-mode-like’ discharge

    Science.gov (United States)

    Schröder, Daniel; Burhenn, Sebastian; de los Arcos, Teresa; Schulz-von der Gathen, Volker

    2015-02-01

    Investigations on the self-pulsing operation regime of a modified micro-scaled atmospheric pressure plasma jet (μ-APPJ) are presented. Using a wedge-shaped electrode configuration, a self-pulsing behavior of the device is achieved, which is characterized by the repetitive ignition of a constricted ‘γ-mode-like’ discharge at the gas inlet, which propagates with the gas flow towards the nozzle, where it extinguishes. The ‘γ-mode-like’ feature coexists with the homogeneous alpha-glow. Synchronized voltage/current and optical emission measurements are presented in order to correlate the evolution of electrical quantities such as voltage, current, dissipated power and phase with changes in the discharge structure. First insights are gained into the underlying discharge dynamics responsible for a stable self-sustainment, propagation and extinction of the constricted discharge. The results indicate that processes induced by helium metastables play a major role. Maximal electron densities on the order of ne = 3.2 · 1012 cm-3 and dissipated power of 18.9 W are achieved in this novel operation regime.

  8. On the homogeneity of a diffuse barrier discharge in atmospheric air between flat cylindrical electrodes

    Science.gov (United States)

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

    2015-05-01

    The degree of homogeneity of a diffuse dielectric barrier discharge in millimeter air gaps under atmospheric pressure has been analyzed. This analysis is based on the glow-brightness distribution in the discharge gap cross section with allowance for a cylindrical electrode shape. It is shown that the degree of discharge homogeneity depends on both the repetition frequency of voltage pulses applied to the discharge gap and the barrier material.

  9. A Monte Carlo Method for Low Pressure Radio Frequency Discharges

    Directory of Open Access Journals (Sweden)

    Lahouaria Settaouti

    2003-06-01

    Full Text Available There is increasing interest in glow discharges because of their importance to a large number of application fields, like the microelectronics industry, flat plasma display panel technology, the laser and light industry and analytical spectrochemistry. To improve the capabilities of rf glow discharges, a good understanding of the discharge physics is highly desirable. The typical calculated results include the radio frequency (rf voltage, the electrical field distribution, the density of argon ions and electrons, the electron energy distribution function and information about the collision processes of the electrons with the Monte Carlo model. These results are presented throughout the discharge axis and as a function of time in the rf cycle. Moreover, we have investigated how many rf cycles have to be followed before a periodic steady state is reached.

  10. Pilot system development in metre-scale laboratory discharge

    OpenAIRE

    Kochkin, Pavlo; Lehtinen, Nikolai; Alexander,; van Deursen, P. J.; Østgaard, Nikolai

    2017-01-01

    The pilot system development in metre-scale negative laboratory discharges is studied with ns-fast photography. The systems appear as bipolar structures in the vicinity of the negative high-voltage electrode. They appear as a result of a single negative streamer propagation and determine further discharge development. Such systems possess features like glowing beads, bipolarity, different brightness of the top and bottom parts, and mutual reconnection. A 1D model of the ionization evolution i...

  11. Atmospheric-pressure electric discharge as an instrument of chemical activation of water solutions

    Science.gov (United States)

    Rybkin, V. V.; Shutov, D. A.

    2017-11-01

    Results of experimental studies and numerical simulations of physicochemical characteristics of plasmas generated in different types of atmospheric-pressure discharges (pulsed streamer corona, gliding electric arc, dielectric barrier discharge, glow-discharge electrolysis, diaphragmatic discharge, and dc glow discharge) used to initiate various chemical processes in water solutions are analyzed. Typical reactor designs are considered. Data on the power supply characteristics, plasma electron parameters, gas temperatures, and densities of active particles in different types of discharges excited in different gases and their dependences on the external parameters of discharges are presented. The chemical composition of active particles formed in water is described. Possible mechanisms of production and loss of plasma particles are discussed.

  12. Computational physics of electric discharges in gas flows

    CERN Document Server

    Surzhikov, Sergey T

    2012-01-01

    Gas discharges are of interest for many processes in mechanics, manufacturing, materials science and aerophysics. To understand the physics behind the phenomena is of key importance for the effective use and development of gas discharge devices. This worktreats methods of computational modeling of electrodischarge processes and dynamics of partially ionized gases. These methods are necessary to tackleproblems of physical mechanics, physics of gas discharges and aerophysics.Particular attention is given to a solution of two-dimensional problems of physical mechanics of glow discharges.The use o

  13. Filamentation of a Magnetized, Radio Frequency Discharge

    Science.gov (United States)

    Konopka, Uwe; Lynch, Brian; Bandyopadhyay, Pintu; Sharma, Devendra; Thomas, Edward

    2014-10-01

    A filamentation instability has been observed in a radio-frequency (rf) discharge that was subject to an externally applied, homogeneous magnetic field. The instability arises in a uniform rf-discharge after the magnetic field strength is sufficiently increased. First, the plasma shows target-like glow structures, followed by spiral structures at higher fields. Finally, the plasma breaks up into individual, string-like, magnetic field aligned filaments that seem to repel each other. A variety of filamentation states can be observed, but their overall shapes follow the aforementioned rule of magnetic field strength dependency. The detailed picture of the discharge glow, however, depends on experiment specific conditions as the geometric shape and type of the discharge electrodes, the discharge pressure and power. In an effort to verify that the observed effect is universal, we compare experimental measurements made using two different high magnetic field, dusty plasma experiment facilities: the experiment that was located at the Max Planck Institute in Garching, Germany and the newly built MDPX (magnetized dusty plasma experiment) at Auburn University, Alabama. In both experimental setups we could observe filamentation. This work is supported from funding from DOE and NSF.

  14. Camp GLOW (Girls Leading Our World): Handbook for Volunteers.

    Science.gov (United States)

    Peace Corps, Washington, DC. Information Collection and Exchange Div.

    Camp GLOW (Girls Leading Our World) began in Romania in 1995 as a weeklong leadership camp with the purpose of encouraging young women to become active citizens by building their self-esteem and confidence, increasing their self-awareness, and developing their skills in goal-setting, assertiveness, and career and life planning. Since that first…

  15. Altruism, warm glow, and charitable giving: Three experiments

    NARCIS (Netherlands)

    Bekkers, R.H.F.P.; Ottoni-Wilhelm, M.; Verkaik, D.J.

    2015-01-01

    One of the key questions in the science of philanthropy is to what extent donations to charity are motivated by altruism – concern for public benefits, including the well-being of recipients – and warm glow – concerns for private benefits, including emotional gratification. To disentangle altruism

  16. SkyGlowNet as a Vehicle for STEM Education

    Science.gov (United States)

    Flurchick, K. M.; Craine, E. R.; Culver, R. B.; Deal, S.; Foster, C.

    2013-06-01

    SkyGlowNet is an emerging network of internet-enabled sky brightness meters (iSBM) that continuously record and log sky brightness at the zenith of each network node site. Also logged are time and weather information. These data are polled at a user-defined frequency, typically about every 45 seconds. The data are uploaded to the SkyGlowNet website, initially to a proprietary area where the data for each institution are embargoed for one or two semesters as students conduct research projects with their data. When released from embargo, the data are moved to another area where they can be accessed by all SkyGlowNet participants. Some of the data are periodically released to a public area on the website. In this presentation we describe the data formats and provide examples of both data content and the structure of the website. Early data from two nodes in the SkyGlowNet have been characterized, both quantitatively and qualitatively, by undergraduate students at NCAT. A summary of their work is presented here. These analyses are of utility in helping those new to looking at these data to understand how to interpret them. In particular, we demonstrate differences between effects on light at night and sky brightness due to astronomical cycles, atmospheric phenomena, and artificial lighting. Quantitative characterization of the data includes statistical analyses of parsed segments of the temporal data stream. An attempt is made to relate statistical metrics to specific types of phenomena.

  17. Thermoluminescence glow curve involving any extent of retrapping ...

    Indian Academy of Sciences (India)

    A simple model is proposed which explains the occurrence of TL glow curve involving any extent of retrapping or any order of kinetics. It has been observed that the extents of recombination and simultaneous rewrapping decide the order of kinetics involved. TL decay parameters, order of kinetics and initial concentration of ...

  18. INTENSE ENERGETIC GAS DISCHARGE

    Science.gov (United States)

    Luce, J.S.

    1960-03-01

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

  19. Atmospheric and sub-atmospheric dielectric barrier discharges in helium and nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Sublet, A [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, CH-1015 Lausanne (Switzerland); Ding, C [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, CH-1015 Lausanne (Switzerland); Dorier, J-L [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, CH-1015 Lausanne (Switzerland); Hollenstein, Ch [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, CH-1015 Lausanne (Switzerland); Fayet, P [Tetra Pak (Suisse) SA, Tetra Pak R and D Plasma Technology, CH-1680 Romont (Switzerland); Coursimault, F [Tetra Pak (Suisse) SA, Tetra Pak R and D Plasma Technology, CH-1680 Romont (Switzerland)

    2006-11-01

    Dielectric barrier discharges (DBDs) are investigated in helium and nitrogen as a function of pressure from 5 to 1000 mbar. Different regimes are observed: glow, Townsend, multi-peak and filamentary, depending on pressure, power and electrode gap. In helium, DBD is a glow-like discharge with a transition to multi-peak or Townsend discharge at high power. In nitrogen, the discharge is Townsend-like and shows a transition to multi-peak mode below 300 mbar. Transition to filamentary mode is observed for large gaps. Fast exposure imaging is used to investigate multi-peak mode in nitrogen. Electrical measurements and time-resolved optical emission spectroscopy are used to characterize the discharge, to study the evolution of metastable species as a function of the pressure and to analyse the discharge startup. These results offer new perspectives for the operation of DBDs in low vacuum.

  20. Heart bypass surgery - discharge

    Science.gov (United States)

    Off-pump coronary artery bypass - discharge; OPCAB - discharge; Beating heart surgery - discharge; Bypass surgery - heart - discharge; CABG - discharge; Coronary artery bypass graft - discharge; Coronary artery ...

  1. Validating the Goldstein-Wehner Law for the Stratified Positive Column of DC Discharge in an Undergraduate Laboratory

    Science.gov (United States)

    Lisovskiy, V. A.; Koval, V. A.; Artushenko, E. P.; Yegorenkov, V. D.

    2012-01-01

    In this paper we suggest a simple technique for validating the Goldstein-Wehner law for a stratified positive column of dc glow discharge while studying the properties of gas discharges in an undergraduate laboratory. To accomplish this a simple device with a pre-vacuum mechanical pump, dc source and gas pressure gauge is required. Experiments may…

  2. 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, ...

  3. Angina - discharge

    Science.gov (United States)

    ... also learn how to take care of your heart disease . Diet and lifestyle Try to limit how much alcohol ... surgery - discharge Heart bypass surgery - minimally invasive - discharge Heart disease - risk ... Review Date 8/2/2016 Updated by: Michael ...

  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. Fe2O3-SiO2 Multi Coating of TiO2 Powder Treated in Atmospheric Pressure Glow Plasma

    Science.gov (United States)

    Kogoma, Masuhiro; Takeda, Atsushi; Tanaka, Kunihito

    Fe oxide-coated TiO2 particles for UV protection cosmetics were produced by means of atmospheric pressure glow discharge using IAA(Iron acethyl acetonato). The particles were also coated by a silica protection layer. To examine the UV catalytic ability of Fe oxide -coated TiO2, we measured a squalene that contained the powders by GCMS for the gas products after the squalene had been irradiated by a Xe lamp for one hour. Using silica-coated TiO2 that was coated by Fe oxide, we find almost no signals from any harmful organic oxides in the GC-MS spectra of the UV irradiated squalene. The multi- coated powder shows very fine and flesh like-color with pearl-like glowing.

  6. Cardiac catheterization - discharge

    Science.gov (United States)

    Catheterization - cardiac - discharge; Heart catheterization - discharge: Catheterization - cardiac; Heart catheterization; Angina - cardiac catheterization discharge; CAD - cardiac catheterization discharge; Coronary ...

  7. Numerical investigation of trichel pulse of negative corona discharge in N2–O2 mixture

    Science.gov (United States)

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

    2017-12-01

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

  8. Thermoluminescence glow curve analysis and CGCD method for erbium doped CaZrO3 phosphor

    Science.gov (United States)

    Tiwari, Ratnesh; Chopra, Seema

    2016-05-01

    The manuscript report the synthesis, thermoluminescence study at fixed concentration of Er3+ (1 mol%) doped CaZrO3 phosphor. The phosphors were prepared by modified solid state reaction method. The powder sample was characterized by thermoluminescence (TL) glow curve analysis. In TL glow curve the optimized concentration in 1mol% for UV irradiated sample. The kinetic parameters were calculated by computerized glow curve deconvolution (CGCD) techniaue. Trapping parameters gives the information of dosimetry loss in prepared phosphor and its usability in environmental monitoring and for personal monitoring. CGCD is the advance tool for analysis of complicated TL glow curves.

  9. A new gas discharge process for preparation of non-fouling surfaces on biomaterials

    NARCIS (Netherlands)

    Sheu, M.S.; Hoffman, A.S.; Terlingen, J.G.A.; Feijen, Jan

    1993-01-01

    A non-fouling surface containing immobilized polyethylene oxide (PEO) was achieved using an argon radio-frequency glow discharge treatment (RFGD) of polyethylene films precoated with Brij hydrocarbon-PEO surfactants. Surface wettability of RFGD-treated and washed surfaces increased the most when PEO

  10. Surface Cleaning by Glow Discharge in High-Volume Gas Flow

    Science.gov (United States)

    1976-04-07

    was used with a #25 size hypodermic needle the results are shown in Table 2. A slightly smaller drop was obtained when using the same size needle coated...small to measure, indicates a surface free of both water and of substances which are hydrophobic. The theory of the significance of the small contact...and its diameter when spread out over the surface of the clean specimen. The experiment data to test the following theory , was accumulated by measuring

  11. 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%.

  12. 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.

  13. Absolute number densities of helium metastable atoms determined by atomic absorption spectroscopy in helium plasma-based discharges used as ambient desorption/ionization sources for mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Reininger, Charlotte; Woodfield, Kellie [Brigham Young University, Department of Chemistry and Biochemistry, Provo, UT 84602 (United States); Keelor, Joel D.; Kaylor, Adam; Fernández, Facundo M. [Georgia Institute of Technology, School of Chemistry and Biochemistry, Atlanta, GA 30332 (United States); Farnsworth, Paul B., E-mail: paul_farnsworth@byu.edu [Brigham Young University, Department of Chemistry and Biochemistry, Provo, UT 84602 (United States)

    2014-10-01

    The absolute number densities of helium atoms in the 2s {sup 3}S{sub 1} metastable state were determined in four plasma-based ambient desorption/ionization sources by atomic absorption spectroscopy. The plasmas included a high-frequency dielectric barrier discharge (HF-DBD), a low temperature plasma (LTP), and two atmospheric-pressure glow discharges, one with AC excitation and the other with DC excitation. Peak densities in the luminous plumes downstream from the discharge capillaries of the HF-DBD and the LTP were 1.39 × 10{sup 12} cm{sup −3} and 0.011 × 10{sup 12} cm{sup −3}, respectively. Neither glow discharge produced a visible afterglow, and no metastable atoms were detected downstream from the capillary exits. However, densities of 0.58 × 10{sup 12} cm{sup −3} and 0.97 × 10{sup 12} cm{sup −3} were measured in the interelectrode regions of the AC and DC glow discharges, respectively. Time-resolved measurements of metastable atom densities revealed significant random variations in the timing of pulsed absorption signals with respect to the voltage waveforms applied to the discharges. - Highlights: • We determine He metastable number densities for four plasma types • The highest number densities were observed in a dielectric barrier discharge • No helium metastable atoms were observed downstream from the exits of glow discharges.

  14. Effect of the field dependence of the coefficient of ion-electron emission on the characteristics of a normal cathode discharge

    NARCIS (Netherlands)

    Azarov, AV; Ochkin, VN

    2004-01-01

    The electric characteristics of the cathode layer of a normal glow discharge are discussed. The value of the normal current density and its dependence on the discharge parameters are modeled within a one-dimensional drift approximation with a local ionization. The dependence of the coefficient of

  15. A self-consistent fluid model for radio-frequency discharges in SiH4-H-2 compared to experiments

    NARCIS (Netherlands)

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

    1997-01-01

    A one-dimensional fluid model for radio-frequency glow discharges is presented which describes silane/hydrogen discharges that are used for the deposition of amorphous silicon (a-Si:H). The model is used to investigate the relation between the external settings (such as pressure, gas inlet, applied

  16. Transitions of an atmospheric-pressure diffuse dielectric barrier discharge in helium for frequencies increasing from kHz to MHz

    Science.gov (United States)

    Boisvert, J.-S.; Margot, J.; Massines, F.

    2017-03-01

    Recent studies have shown that tuning a dielectric barrier discharge (DBD) in the medium-frequency range (MF: from 0.3 to 3 MHz) allows a low-power and a high-power mode to be sustained. In the present article the effect of the driving frequency on a DBD is studied from the low-frequency range (LF: from 30 to 300 kHz) to the high-frequency range (HF: from 3 to 30 MHz). This is achieved using fast imaging together with electrical and spectroscopic diagnostics. At every frequency, a diffuse discharge is sustained. It is observed that at 25 kHz the discharge is an atmospheric-pressure glow discharge (APGD) while at 15 MHz the discharge behaves as a capacitive discharge in the RF-α mode. The usual LF APGD behavior is observed up to 100 kHz. Above 200 kHz, the positive column remains during the whole cycle so that the hybrid mode is sustained. At 5 MHz, the hybrid mode finally turns into the RF-α mode. In addition to the LF APGD, RF-α and hybrid modes obtained when the applied voltage is significantly higher than the ignition value, two other modes can be reached at low applied voltage. A Townsend-like mode is achieved from 50 to 100 kHz while in the medium-frequency range, the Ω mode is sustained. Moreover, only from 1.0 to 2.7 MHz there is a large hysteresis occurring when the discharge transits back and forth from the Ω to the hybrid mode. It is also found that when the frequency increases from 25 kHz to 15 MHz, the rms current increases over two orders of magnitudes while the rms voltage decreases by about 60%. The gas temperature estimated from N2 rotational spectra is always close to room temperature but the discharge is more energy efficient (in the HF range) as a lower fraction of energy turns into gas heating.

  17. Combined influence of the impurities and radial electric field on dielectric barrier discharges in atmospheric helium

    Science.gov (United States)

    Huang, Zhiming; Hao, Yanpeng; Han, Yuying; Yang, Lin; Tang, Li; Liao, Yifan; Li, Licheng

    2017-11-01

    The combined influence of nitrogen impurities and radial electric field on dielectric barrier discharges in atmospheric helium is investigated using a two-dimensional (2D) fluid simulation. Discharge current waveforms, 2D electron densities, distributions of surface charge, and radial and axial components of the electric field at the electrode edge are calculated for different impurity levels varying from 0 to 30 ppm. It is observed that the discharge presents the characteristic of a column in pure helium, and it gradually becomes a relatively uniform glow discharge as the impurity level is increased to 20 ppm; for the higher impurity level of 30 ppm, the discharge adopts a concentric-ring pattern discharge. Our result shows that the radial electric field at the electrode edge is approximately 0.6-1.2 kV/cm during the discharge. This radial electric field has an effect that leads to a non-uniform discharge. After doping a low level of impurities, the Penning ionizations caused by the impurities can inhibit this effect and lead to a uniform discharge. However, for a higher impurity level (30 ppm), the effect of the radial electric field again becomes dominant, which easily leads to a non-uniform discharge. These results provide a new perspective on obtaining a uniform glow discharge when both influences of the impurity and radial electric field are taken into account.

  18. Glow experiment documentation of OMS/RCS pods and vertical stabilizer

    Science.gov (United States)

    1982-01-01

    Glow experiment documentation of orbital maneuvering system (OMS) reaction control system (RCS) pods and vertical stabilizer shows chemo-luminescent effect resulting from atomic oxygen impacting the spacecraft and building to the point that the atomic oxygen atoms combine to form molecules of oxygen. Image intensifier on NIKON 35mm camera was used to record glow on vertical tail and OMS pods.

  19. Glow experiment documentation of OMS/RCS pod and vertical stabilizer

    Science.gov (United States)

    1982-01-01

    Glow experiment documentation of one of the orbital maneuvering system (OMS) reaction control system (RCS) pods and a portion of the vertical stabilizer shows chemoluminescent effectresulting from atomic oxygen impacting the spacecraft and building to the point that the atomic oxygen atoms combine to form molecules of oxygen. The Image Intensifier on NIKON 35mm camera was used to record the glow.

  20. Numerical analysis of thermoluminescence glow curves; Analisis numerico de las cruvas de termoluminiscencia

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Ros, J. M.; Delgado, A.

    1989-07-01

    This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs.

  1. Deconvolution and simulation of thermoluminescence glow curves with Mathcad.

    Science.gov (United States)

    Kiisk, V

    2013-09-01

    The paper reports two quite general and user-friendly calculation codes (called TLD-MC and TLS-MC) for deconvolution and simulation, respectively, of thermoluminescence (TL) glow curves, which have been implemented using the well-known engineering computing software PTC Mathcad. An advantage of this commercial software is the flexibility and productivity in setting up tailored computations due to a natural math notation, an interactive calculation environment and the availability of advanced numerical methods. TLD-MC includes the majority of popular models used for TL glow-curve deconvolution (the user can easily implement additional models if necessary). The least-squares (Levenberg-Marquardt) optimisation of various analytical and even some non-analytical models is reasonably fast and the obtained figure-of-merit values are generally excellent. TLS-MC implements numerical solution of the original set of differential equations describing charge carrier dynamics involving arbitrary number of interactive electron and hole traps. The programs are freely available from the website http://www.physic.ut.ee/~kiisk/mcadapps.htm.

  2. Ear discharge

    Science.gov (United States)

    ... antibiotic medicines, which are placed in the ear. Antibiotics may be given by mouth if a ruptured eardrum from an ear infection is causing the discharge. Alternative Names Drainage from the ear; Otorrhea; Ear bleeding; ...

  3. Osteomyelitis - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000297.htm Osteomyelitis - discharge To use the sharing features on this page, please enable JavaScript. You have osteomyelitis , a bone infection caused by bacteria or other ...

  4. Accounting protesting and warm glow bidding in Contingent Valuation surveys considering the management of environmental goods

    DEFF Research Database (Denmark)

    Grammatikopoulou, Ioanna; Olsen, Søren Bøye

    2013-01-01

    Based on a Contingent Valuation survey aiming to reveal the willingness to pay (WTP) for conservation of a wetland area in Greece, we show how protest and warm glow motives can be taken into account when modeling WTP. In a sample of more than 300 respondents, we find that 54% of the positive bids...... are rooted to some extent in warm glow reasoning while 29% of the zero bids can be classified as expressions of protest rather than preferences. In previous studies, warm glow bidders are only rarely identified while protesters are typically identified and excluded from further analysis. We test...... for selection bias associated with simple removal of both protesters and warm glow bidders in our data. Our findings show that removal of warm glow bidders does not significantly distort WTP whereas we find strong evidence of selection bias associated with removal of protesters. We show how to correct...

  5. Long duration gamma-ray glows observed from the tops of thunderstorms

    Science.gov (United States)

    Kelley, N.; Smith, D. M.; Dwyer, J. R.; Hazelton, B. J.; Grefenstette, B. W.; Lowell, A.; Splitt, M. E.; Lazarus, S. M.; Rassoul, H. K.

    2011-12-01

    The Airborne Detector for Energetic Lightning Emissions (ADELE) observed 12 γ-ray glows from thunderstorms near Montana and Florida during its Summer 2009 campaign. These glows have been observed from both the ground and air but this is the first evidence that they are a common, long duration occurrence at the tops of thunderclouds. Glows could be evidence that continuous relativistic runaway with feedback limits thunderstorm charging in a way that competes with lightning. We compare our observed glows to local lightning activity and find a slight but poor correlation, indicating that lightning and glows measure different aspects of cloud electrification. We have shown for all 11 of our observed glows in Florida that there is always an active cell nearby, but there were also many passes near active cells that had no observed glow. We will examine the meteorological differences between active lightning cells with and without glows. We have found the spectrum to be very hard for each glow, with a large fraction of the counts being above 5 MeV. Using a Monte Carlo simulation of relativistic runaway with positron feedback and a GEANT3 model of the atmosphere and instrument response from within a plane, we will distinguish between two different possibilities for a hard spectrum: an upward relativistic avalanche very deep in the atmosphere, so that most low energy photons have been removed via Compton scattering, and a downward relativistic avalanche between the upper positive and the screening layer, with the bremsstrahlung from the upward positron beam (a side-effect of feedback) producing the glow. If the latter model is correct, it demonstrates that positron feedback is indeed a common process in thunderclouds.

  6. Transformative Use of an Improved All-Payer Hospital Discharge Data Infrastructure for Community-Based Participatory Research: A Sustainability Pathway.

    Science.gov (United States)

    Salemi, Jason L; Salinas-Miranda, Abraham A; Wilson, Roneé E; Salihu, Hamisu M

    2015-08-01

    To describe the use of a clinically enhanced maternal and child health (MCH) database to strengthen community-engaged research activities, and to support the sustainability of data infrastructure initiatives. Population-based, longitudinal database covering over 2.3 million mother-infant dyads during a 12-year period (1998-2009) in Florida. A community-based participatory research (CBPR) project in a socioeconomically disadvantaged community in central Tampa, Florida. Case study of the use of an enhanced state database for supporting CBPR activities. A federal data infrastructure award resulted in the creation of an MCH database in which over 92 percent of all birth certificate records for infants born between 1998 and 2009 were linked to maternal and infant hospital encounter-level data. The population-based, longitudinal database was used to supplement data collected from focus groups and community surveys with epidemiological and health care cost data on important MCH disparity issues in the target community. Data were used to facilitate a community-driven, decision-making process in which the most important priorities for intervention were identified. Integrating statewide all-payer, hospital-based databases into CBPR can empower underserved communities with a reliable source of health data, and it can promote the sustainability of newly developed data systems. © Health Research and Educational Trust.

  7. Hip fracture - discharge

    Science.gov (United States)

    Inter-trochanteric fracture repair - discharge; Subtrochanteric fracture repair - discharge; Femoral neck fracture repair - discharge; Trochanteric fracture repair - discharge; Hip pinning surgery - ...

  8. The warm glow heuristic: when liking leads to familiarity.

    Science.gov (United States)

    Monin, Benoît

    2003-12-01

    Five studies demonstrate that the positive valence of a stimulus increases its perceived familiarity, even in the absence of prior exposure. For example, beautiful faces feel familiar. Two explanations for this effect stand out: (a). Stimulus prototypicality leads both to positivity and familiarity, and (b). positive affect is used to infer familiarity in a heuristic fashion. Studies 1 and 2 show that attractive faces feel more familiar than average ones and that prototypicality accounts for only part of this effect. In Study 3, the rated attractiveness of average faces was manipulated by contrast, and their perceived familiarity changed accordingly, although their inherent prototypicaliry remained the same. In Study 4, positive words felt more familiar to participants than neutral and negative words. Study 5 shows that the effect is strongest when recognition is difficult. The author concludes that both prototypicality and a warm glow heuristic are responsible for the "good-is-familiar" phenomenon.

  9. Does exclusion of protest zeros and warm-glow bidders cause selection bias in Contingent Valuation?

    DEFF Research Database (Denmark)

    Grammatikopoulou, Ioanna; Olsen, Søren Bøye; Pouta, Eija

    the true WTP due to protest behavior. We conduct a contingent valuation study to estimate the WTP for conserving a Natura 2000 wetland area in Greece. We find that 54% of the positive bidders exert warm glow motivations while 29% of all responses can be classified as protest zero bids. We employ three...... different models to test for the potential impacts of how these positive warm glow and protest zero bidders are treated. We first exclude the warm glow cases, secondly we include them, and, finally, we correct for selection bias by using the Full Information Maximum Likelihood method for grouped data model...

  10. Micro-structured electrode arrays : high-frequency discharges at atmospheric pressure—characterization and new applications

    NARCIS (Netherlands)

    Baars-Hibbe, Lutz; Schrader, Christian; Sichler, Philipp; Cordes, Thorben; Gericke, Karl-Heinz; Büttgenbach, Stephanus; Draeger, Siegfried

    2004-01-01

    Micro-structured electrode (MSE) arrays allow to generate large-area uniform glow discharges over a wide pressure range up to atmospheric pressure. The electrode dimensions in the µm-range realized by means of modern micro-machining and galvanic techniques are small enough to generate sufficiently

  11. Diagnosis of the local thermal equilibrium by optical emission spectroscopy in the evolution of electric discharge; Diagnostico del equilibrio termico local por espectroscopia optica de emision en la evolucion de una descarga electrica

    Energy Technology Data Exchange (ETDEWEB)

    Valdivia B, R.; Pacheco S, J.; Pacheco P, M.; Ramos F, F.; Cruz A, A. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Velazquez P, S. [Instituto Tecnologico de Toluca, Av. Instituto Tecnologico s/n, Ex-Rancho la Virgen, Metepec 52140, Estado de Mexico (Mexico)

    2008-07-01

    In this work applies the technique of optical emission spectroscopy to diagnose the temperature of the species generated in plasma in the transition to glow discharge arc. Whit this diagnosis is possible to determine the local thermal equilibrium conditions of the discharge. (Author)

  12. TL glow curve analysis of UV, beta and gamma induced limestone collected from Amarnath holy cave

    Directory of Open Access Journals (Sweden)

    Vikas Dubey

    2015-01-01

    Full Text Available The paper reports themoluminescence glow curve analysis of UV (ultraviolet, β (beta and γ (gamma induced limestone collected from Amarnath holy cave. The collected natural sample was characterized by X-ray diffraction (XRD technique and crystallite size calculated by Scherer's formula. Surface morphology and particle size was calculated by transmission electron microscopy (TEM study. Effect of annealing temperature on collected lime stone examined by TL glow curve study. The limestone was irradiated by UV radiation (254 nm source and the TL glow curve recorded for different UV exposure time. For beta irradiation Sr90 source was used and is shows intense peak at 256 °C with a shoulder peak at higher temperature range. For gamma radiation Co60 source and TL glow curve recorded for different doses of gamma. The kinetic parameters calculation was performed for different glow curve by computerized glow curve deconvolution (CGCD technique. The chemical composition of natural limestone was analyzed by energy dispersive X-ray spectroscopy (EDXS.

  13. Study of the glow curve structure of the minerals separated from black pepper (Piper nigrum L.)

    Science.gov (United States)

    Guzmán, S.; Ruiz Gurrola, B.; Cruz-Zaragoza, E.; Tufiño, A.; Furetta, C.; Favalli, A.; Brown, F.

    2011-04-01

    The inorganic mineral fraction extracted from black pepper (Piper nigrum L.) has been analysed using a thermoluminescence (TL) method, investigating the glow curve structure, including an evaluation of the kinetic parameters. Different grain sizes, i.e. 10, 74, and 149 μm, were selected from commercial black pepper. The X-ray diffraction of the inorganic fraction shows that quartz is the main mineral present in it. The samples were exposed to 1-25 kGy doses by gamma rays of 60Co in order to analyse the thermally stimulated luminescence response as a function of the delivered dose. The glow curves show a complex structure for different grain sizes of the pepper mineral samples. The fading of the TL signal at room temperature was obtained after irradiation, and it was observed that the maximum peaks of the glow curves shift towards higher values of the temperature when the elapsed time from irradiation increases. It seems that the fading characteristic may be related to a continuous trap distribution responsible for the complex structure of the glow curve. Similar glow curves structure behaviour was found under ultraviolet irradiation of the samples. The activation energy and the frequency factor were determined from the glow curves of different grain sizes using a deconvolution programme because of the evident complexity of the structure.

  14. Two-dimensional simulation of filaments in barrier discharges

    CERN Document Server

    Steinle, G; Hiller, W; Pietralla, M

    1999-01-01

    We present a fluid model for barrier discharges in air at atmospheric pressure with spectral resolved photonic secondary processes, implemented with general finite-element software. The results show five different discharge phases, a homogenous and a space-charge dominated avalanche phase, a phase of dielectric charging with field enhancement due to positive ions causing streamer formation, a cathode streamer and a subsequent glow-discharge phase with a cathode-fall region. Quenching of the microdischarge occurs after a few nanoseconds by the increasing charge on the dielectric. While the capacity of the dielectric has nearly no influence on the energetic efficiency of radical production and vacuum-UV-irradiation of the dielectric, a higher voltage causes a small decrease in radical efficiency and a significant increase in the efficiency of VUV-irradiation of the dielectric. (author)

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

    Science.gov (United States)

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

    2018-01-01

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

  16. Stereotactic radiosurgery - discharge

    Science.gov (United States)

    ... discharge; Linear accelerator - discharge; Lineacs - discharge; Proton beam radiosurgery - discharge ... You received stereotactic radiosurgery (SRS), or radiotherapy. This is a form of radiation therapy that focuses high-powered x-rays onto a small ...

  17. Atrial fibrillation - discharge

    Science.gov (United States)

    Auricular fibrillation - discharge; A-fib - discharge; AF - discharge; Afib - discharge ... Avoid salty and fatty foods. Stay away from fast-food restaurants. ... how to check your pulse, and check it every day. It is better ...

  18. Effects of time-temperature profiles on glow curves of germanium-doped optical fibre

    Science.gov (United States)

    Lam, S. E.; Alawiah, A.; Bradley, D. A.; Mohd Noor, N.

    2017-08-01

    The Germanium (Ge) doped silica optical fibres have demonstrated the great potential to be developed as a thermoluminescent (TL) dosimeter that can be used in various applications in radiotherapy, diagnostic radiology, UV dosimetry system and food irradiation industry. Different time-temperature profile (TTP) parameters of the TL reader have been employed by many researchers in various of TL studies. Nevertheless, none of those studies adequately addressed the effects of the reader's preheat temperature and heating rate on the kinetic parameters of the TL glow curve specifically, the Ge-doped silica optical fibres. This research addresses the issue of TTP parameters with special attention to the determination of the kinetic parameters of the glow curve. The glow curve responses were explored and the kinetic parameters were analyzed by the WinGCF software, to show the effect of the preheat temperature and heating rate of the reader on Ge-doped fibre irradiated with 18 Gy of 6 MV photons radiation. The effect of TTP parameters was discussed and compared against the commercial fibre and tailored made fibre of 6 mol% Ge-doped of flat and cylindrical shape. The deconvolution of glow peaks and the kinetic parameters were obtained by the WinGCF software. This enables to fit accurately (1.5%glow curves. A positive, moderate linear relationship exists between the TL response and the heating rate when the specific preheat temperature was used to read commercial fibre (50 °C) and cylindrical fibre (80 °C and 160 °C). It is found that the glow peaks of cylindrical fibre exhibit the highest peak integral as compared to flat and commercial fibres. This study revealed the possible relationship between the reader's TTP parameters and the kinetic parameters of TL glow curves for the commercial and tailored made Ge-doped silica optical fibres.

  19. Thermoluminescence glow curve analysis and CGCD method for erbium doped CaZrO{sub 3} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, Ratnesh, E-mail: 31rati@gmail.com [Department of Physics, Bhilai Institute of Technology, Raipur, 493661 (India); Chopra, Seema [Department Physics, G.D Goenka Public School (India)

    2016-05-06

    The manuscript report the synthesis, thermoluminescence study at fixed concentration of Er{sup 3+} (1 mol%) doped CaZrO{sub 3} phosphor. The phosphors were prepared by modified solid state reaction method. The powder sample was characterized by thermoluminescence (TL) glow curve analysis. In TL glow curve the optimized concentration in 1mol% for UV irradiated sample. The kinetic parameters were calculated by computerized glow curve deconvolution (CGCD) techniaue. Trapping parameters gives the information of dosimetry loss in prepared phosphor and its usability in environmental monitoring and for personal monitoring. CGCD is the advance tool for analysis of complicated TL glow curves.

  20. Glow-curve deconvolution of thermoluminescence curves in the simplified OTOR equation using the Hybrid Genetic Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Lovedy Singh, L., E-mail: lovedyo1@yahoo.co.in; Gartia, R.K.

    2014-01-15

    Highlights: • Use of Hybrid Genetic Algorithm in TL analysis. • Deconvolution in simplified OTOR equation. • Glow curve analysis. -- Abstract: A novel method of analyzing thermoluminescence TL glow curves is presented here. This method is based on the recently derived simplified OTOR equation. It employs the Hybrid Genetic Algorithm for the extraction of the TL parameters. This method has been tested against theoretical glow-curve data that were generated using the full iteration method without any prior approximation in the OTOR model, and it has also been tested using the complex glow curve of NaCl.

  1. High-performance cathode elements for gas-discharge light sources

    Directory of Open Access Journals (Sweden)

    Sevastyanov V. V.

    2009-02-01

    Full Text Available Application of cathode elements of the arc-discharge activator made on the basis of developed material — alloy of iridium and rare-earth metals (of cerium group — has been suggested. The working samples of arc lamps have been produced and tested. The location of metal-alloy cathode has been optimized. The tests demonstrated, that after 4500 hours of work the lighting-up and glowing parameters of such lamps remained stable.

  2. Thermoluminescence systems with two or more glow peaks described by anomalous kinetic parameters

    Energy Technology Data Exchange (ETDEWEB)

    Levy, P.W.

    1983-01-01

    The usual first and second order TL kinetic expressions are based on a number of assumptions, including the usually unstated assumption that charges released from one type of trap, giving rise to one glow peak, are not retrapped on other types of traps, associated with other glow peaks. Equations have been developed describing TL systems in which charges released from one type of trap may be retrapped in other types of traps. Called interactive kinetic equations, they are quite simple but have been studied by numerical methods. In particular, glow curves computed from the interactive kinetic equations have been regarded as data and analyzed by fitting them to the usual first and second order kinetic expressions. All of the anomalous features described above are reproduced. For example, usually the computed glow peaks are well fitted by the first and second order expressions over their upper 60 to 80% but not in the wings. This explains why the usual analysis methods, especially those utilizing peak temperature, full width, etc. appear to describe such peaks. Often unrealistic kinetic parameters are often obtained. Furthermore, the computed glow curves often reproduce the observed dependence on dose.

  3. Glow gel hand washing in the waiting room: a novel approach to improving hand hygiene education.

    Science.gov (United States)

    Fishbein, Anna B; Tellez, Itza; Lin, Henry; Sullivan, Christine; Groll, Mary E

    2011-07-01

    To characterize handwashing behaviors of children and assess the efficacy of a waiting room-based hand hygiene intervention at improving handwashing ability. Prospective randomized pilot study. Emergency department waiting room at a freestanding urban pediatric hospital. Children (8-18 years) and their parent. Participants were randomized to glow gel hand washing without hand hygiene education or glow gel hand washing with hand hygiene education. After participants washed with glow gel, "dirty areas" were illuminated using a black light, and hands were scored. A questionnaire about handwashing behavior was administered. All subjects returned 2-4 weeks after intervention to repeat glow gel hand washing and the questionnaire. Sixty pediatric patients and 57 parents were recruited, with 77% of patients returning for follow up. Patients were 50% male, 58% Latino, 28% African American, and 8% Caucasian. At the initial visit, 91% of children reported hand washing after using the bathroom and 78% reported hand washing before dinner. On the basis of objective scoring, all children improved handwashing ability when compared with the initial visit (P = .02) and were more likely to use warm water at follow up (P = .01). Parents did not significantly improve in handwashing ability (P = .73). Glow gel hand washing is an effective method to improve children's handwashing ability. This short-term intervention was effective even in the absence of specific hand hygiene education. This intervention could serve as a valuable public health measure to teach hand washing in healthcare settings.

  4. High-voltage discharge in supersonic jet of plumbum vapor

    Science.gov (United States)

    Amirov, R. Kh; Antonov, N. N.; Liziakin, G. D.; Polistchook, V. P.; Samoylov, I. S.; Usmanov, R. A.; Yartsev, I. M.

    2015-11-01

    During study of vacuum discharge in plumbum evaporating from molybdenum crucible in identical geometry of discharge gap and the same crucible temperature existence of two different discharge forms were observed. These two forms are vacuum arc with current above 10 A and voltage about 15 V and high-voltage discharge with current about 10 mA and voltage of 340 V. Plumbum was placed in heat-isolated crucible (cathode). Electron-beam heater was situated under the crucible. At the temperature of 1.25 kK that corresponds to plumbum saturated vapor pressure about 0.1 kPa voltage from power source (380 V, 200 A) was applied to anode and high-voltage discharge initiated with characteristics mentioned above. After a few seconds this discharge could turn into arc or could exist hundreds of seconds until total plumbum evaporation. Glow of discharge could take the form of a cone, harness or plasma bunch that hanged at the appreciable distance from the electrodes. The estimations of plasma parameters are presented.

  5. Self-stabilized discharge filament in plane-parallel barrier discharge configuration: formation, breakdown mechanism, and memory effects

    Science.gov (United States)

    Tschiersch, R.; Nemschokmichal, S.; Bogaczyk, M.; Meichsner, J.

    2017-10-01

    Single self-stabilized discharge filaments were investigated in the plane-parallel electrode configuration. The barrier discharge was operated inside a gap of 3 mm shielded by glass plates to both electrodes, using helium-nitrogen mixtures and a square-wave feeding voltage at a frequency of 2 kHz. The combined application of electrical measurements, ICCD camera imaging, optical emission spectroscopy and surface charge diagnostics via the electro-optic Pockels effect allowed the correlation of the discharge development in the volume and on the dielectric surfaces. The formation criteria and existence regimes were found by systematic variation of the nitrogen admixture to helium, the total pressure and the feeding voltage amplitude. Single self-stabilized discharge filaments can be operated over a wide parameter range, foremost, by significant reduction of the voltage amplitude after the operation in the microdischarge regime. Here, the outstanding importance of the surface charge memory effect on the long-term stability was pointed out by the recalculated spatio-temporally resolved gap voltage. The optical emission revealed discharge characteristics that are partially reminiscent of both the glow-like barrier discharge and the microdischarge regime, such as a Townsend pre-phase, a fast cathode-directed ionization front during the breakdown and radially propagating surface discharges during the afterglow.

  6. Heating rate effect on thermoluminescence glow curves of LiF:Mg,Cu,P+PTFE phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Cruz-Zaragoza, E. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, Mexico D.F. 04510 (Mexico); Gonzalez, P.R., E-mail: pedro.gonzalez@inin.gob.mx [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca S/N, C.P. 52750, Ocoyoacac, Estado de Mexico (Mexico); Azorin, J. [Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, 09340 Mexico D.F. (Mexico); Furetta, C. [Touro University Rome, Division of Touro College New York, Circne Gianicolense 15-17, 00153 Rome (Italy)

    2011-10-15

    The influence of heating rate on the thermoluminescence (TL) property of LiF:Mg,Cu,P+PTFE was analyzed. The activation energy and the frequency factor as a function of the heating rate were determined. The kinetic parameters and their dependence on the heating rate were evaluated using the sequential quadratic programming glow curve deconvolution (SQPGCD). The results showed that as the heating rate increases, the peak intensity at the maximum (I{sub M}) decreases and shifts to higher temperature; similar behavior of the kinetics parameters was observed. - Highlights: >Heating rate influence on the thermoluminescence (TL) property of LiF:Mg,Cu,P was analyzed. > The kinetic parameters, activation energy and frequency factor were evaluated using the sequential quadratic programming glow curve deconvolution. > The peak intensity at the maximum (I{sub M}) of the glow curves decreases. > Shifts to higher temperature were observed as the heating rate increased. > Similar behavior of the kinetics parameters was noticed.

  7. Apocenter Glow in Eccentric Debris Disks: Implications for Fomalhaut and Epsilon Eridani

    Science.gov (United States)

    Pan, Margaret; Nesvold, Erika R.; Kuchner, Marc J.

    2016-01-01

    Debris disks often take the form of eccentric rings with azimuthal asymmetries in surface brightness. Such disks are often described as showing pericenter glow, an enhancement of the disk brightness in regions nearest the central star. At long wavelengths, however, the disk apocenters should appear brighter than their pericenters: in the long-wavelength limit, we find that the apocenter pericenter flux ratio scales as 1 + e for disk eccentricity e. We produce new models of this apocenter glow to explore its causes and wavelength dependence and study its potential as a probe of dust grain properties. Based on our models, we argue that several far-infrared and (sub)millimeter images of the Fomalhaut and Epsilon Eridani debris rings obtained with Herschel, JCMT, SHARC II, ALMA, and ATCA should be reinterpreted as suggestions or examples of apocenter glow. This reinterpretation yields new constraints on the disks dust grain properties and size distributions.

  8. Computerized glow curve deconvolution of thermoluminescent emission from polyminerals of Jamaica Mexican flower

    Science.gov (United States)

    Favalli, A.; Furetta, C.; Zaragoza, E. Cruz; Reyes, A.

    The aim of this work is to study the main thermoluminescence (TL) characteristics of the inorganic polyminerals extracted from dehydrated Jamaica flower or roselle (Hibiscus sabdariffa L.) belonging to Malvaceae family of Mexican origin. TL emission properties of the polymineral fraction in powder were studied using the initial rise (IR) method. The complex structure and kinetic parameters of the glow curves have been analysed accurately using the computerized glow curve deconvolution (CGCD) assuming an exponential distribution of trapping levels. The extension of the IR method to the case of a continuous and exponential distribution of traps is reported, such as the derivation of the TL glow curve deconvolution functions for continuous trap distribution. CGCD is performed both in the case of frequency factor, s, temperature independent, and in the case with the s function of temperature.

  9. Double Glow Plasma Surface Alloying Antibacterial Silver Coating on Pure Titanium

    Science.gov (United States)

    Lin, Naiming; Guo, Junwen; Hang, Ruiqiang; Zou, Jiaojuan; Tang, Bin

    2014-12-01

    In order to endow the commercial pure titanium dental implant material with antibacterial property and aimed at avoiding the invalidation that is caused by bacterial adhesion on the surface, a silver coating was fabricated via double glow plasma surface alloying. The antibacterial property of the silver coating was assessed via in vitro estimation. The results showed that a continuous and compact coating was formed. The silver coating had absolute superiority in antibacterial property to raw commercial pure titanium. Double glow plasma surface alloying with silver on commercial pure titanium dental implant material could be considered as a potentially effective method for preventing bacterial adhesion.

  10. The Rose-red Glow of Star Formation

    Science.gov (United States)

    2011-03-01

    The vivid red cloud in this new image from ESO's Very Large Telescope is a region of glowing hydrogen surrounding the star cluster NGC 371. This stellar nursery lies in our neighbouring galaxy, the Small Magellanic Cloud. The object dominating this image may resemble a pool of spilled blood, but rather than being associated with death, such regions of ionised hydrogen - known as HII regions - are sites of creation with high rates of recent star birth. NGC 371 is an example of this; it is an open cluster surrounded by a nebula. The stars in open clusters all originate from the same diffuse HII region, and over time the majority of the hydrogen is used up by star formation, leaving behind a shell of hydrogen such as the one in this image, along with a cluster of hot young stars. The host galaxy to NGC 371, the Small Magellanic Cloud, is a dwarf galaxy a mere 200 000 light-years away, which makes it one of the closest galaxies to the Milky Way. In addition, the Small Magellanic Cloud contains stars at all stages of their evolution; from the highly luminous young stars found in NGC 371 to supernova remnants of dead stars. These energetic youngsters emit copious amounts of ultraviolet radiation causing surrounding gas, such as leftover hydrogen from their parent nebula, to light up with a colourful glow that extends for hundreds of light-years in every direction. The phenomenon is depicted beautifully in this image, taken using the FORS1 instrument on ESO's Very Large Telescope (VLT). Open clusters are by no means rare; there are numerous fine examples in our own Milky Way. However, NGC 371 is of particular interest due to the unexpectedly large number of variable stars it contains. These are stars that change in brightness over time. A particularly interesting type of variable star, known as slowly pulsating B stars, can also be used to study the interior of stars through asteroseismology [1], and several of these have been confirmed in this cluster. Variable stars

  11. An exact calculation of the N2+ and H2+ influx at cathode surface in N2–H2 discharges

    Directory of Open Access Journals (Sweden)

    K.S. Suraj

    2014-01-01

    Full Text Available An exact calculation of N2+ and H2+ influx, at cathode surface in N2–H2 discharge, has been derived using electron impact ionization cross-section at plasma sheath boundary. The analytical formula is very convenient in practical applications. Through the analysis of experimental parameters for glow discharge plasma nitriding, the formula explains, why treatment in an N2–H2 mixture with H2 percentage ∼70% gives most enhanced result.

  12. Density distributions of OH, Na, water vapor, and water mist in atmospheric-pressure dc helium glow plasmas in contact with NaCl solution

    Science.gov (United States)

    Sasaki, Koichi; Ishigame, Hiroaki; Nishiyama, Shusuke

    2015-07-01

    This paper reports the density distributions of OH, Na, water vapor and water mist in atmospheric-pressure dc helium glow plasmas in contact with NaCl solution. The densities of OH, Na and H2O had different spatial distributions, while the Na density had a similar distribution to mist, suggesting that mist is the source of Na in the gas phase. When the flow rate of helium toward the electrolyte surface was increased, the distributions of all the species densities concentrated in the neighboring region to the electrolyte surface more significantly. The densities of all the species were sensitive to the electric polarity of the power supply. In particular, we never detected Na and mist when the electrolyte worked as the anode of the dc discharge. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  13. Characteristics and applications of diffuse discharge of water electrode in air

    Science.gov (United States)

    Wenzheng, LIU; Tahan, WANG; Xiaozhong, CHEN; Chuanlong, MA

    2018-01-01

    Plasma water treatment technology, which aims to produce strong oxidizing reactive particles that act on the gas–liquid interface by way of discharging, is used to treat the organic pollutants that do not degrade easily in water. This paper presents a diffuse-discharge plasma water treatment method, which is realized by constructing a conical air gap through an uneven medium layer. The proposed method uses water as one electrode, and a dielectric barrier discharge electrode is constructed by using an uneven dielectric. The electric field distribution in the discharge space will be uneven, wherein the long gap electric field will have a smaller intensity, while the short one will have a larger intensity. A diffuse glow discharge is formed in the cavity. With this type of plasma water treatment equipment, a methyl orange solution with a concentration of 10 mg l‑1 was treated, and the removal rate was found to reach 88.96%.

  14. Scaled-Up Nonequilibrium Air Plasmas Generated by DC and Pulsed Discharges

    Science.gov (United States)

    2010-09-08

    decontamination or flue gas cleaning [7-9]). We suppose that during the initial phase of the spark pulse, the strong chemical effect can be maintained thanks to...streamer-to-spark transition discharge in air at atmospheric pressure is presented. The transient spark (TS) is applicable for flue gas cleaning or bio...the gas composition, flow rate, value of R and geometry of electrodes [22–24]. Glow discharge has already been applied e. g. for flue gas cleaning [22,25

  15. Concussion - adults - discharge

    Science.gov (United States)

    Brain injury - concussion - discharge; Traumatic brain injury - concussion - discharge; Closed head injury - concussion - discharge ... a car Ski, snowboard, skate, skateboard, or do gymnastics or martial arts Participate in any activity where ...

  16. Tennis elbow surgery - discharge

    Science.gov (United States)

    Lateral epicondylitis surgery - discharge; Lateral tendinosis surgery - discharge; Lateral tennis elbow surgery - discharge ... Soon after surgery, severe pain will decrease, but you may have mild soreness for 3 to 6 months.

  17. 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 ...

  18. Ventriculoperitoneal shunt - discharge

    Science.gov (United States)

    ... VP shunt - discharge; Shunt revision - discharge; Hydrocephalus shunt placement - discharge ... The major problems to watch for are an infected shunt and a blocked shunt. Call your child's provider if your child ...

  19. Thermal analysis of high pressure micro plasma discharge

    Science.gov (United States)

    Mobli, Mostafa

    resistor and capacitance. A detailed gas phase chemical kinetic model was also implemented. One-dimensional simulation has been performed to study the effects of the neutral gas temperature on a micro plasma discharge operating in the "abnormal" glow mode. In addition, two dimensional simulation has been conducted to simulate the "normal" glow regime of a micro plasma discharge that has multi-dimensional spatial dependence. The effects of conjugate heat transfer on the gas temperature distribution and the overall plasma characteristics i.e. the voltage-current curve and electron number density has been investigated. The conjugate heat transfer is found to significantly affect the plasma behavior. Finally a temporally varying temperature boundary condition has been proposed that reduces the computational overhead but resolves the conjugate heat transfer effect with reasonable accuracy.

  20. Prostate brachytherapy - discharge

    Science.gov (United States)

    Implant therapy - prostate cancer - discharge; Radioactive seed placement - discharge ... You had a procedure called brachytherapy to treat prostate cancer. Your treatment lasted 30 minutes or more, ...

  1. Simulation of Thermal and Chemical Relaxation in a Post-Discharge Air Corona Reactor

    CERN Document Server

    Meziane, M; Ducasse, O; Yousfi, M

    2016-01-01

    In a DC point-to-plane corona discharge reactor, the mono filamentary streamers cross the inter electrode gap with a natural repetition frequency of some tens of kHz. The discharge phase (including the primary and the secondary streamers development) lasts only some hundred of nanoseconds while the post-discharge phases occurring between two successive discharge phases last some tens of microseconds. From the point of view of chemical activation, the discharge phases create radical and excited species located inside the very thin discharge filaments while during the post-discharge phases these radical and excited species induce a chemical kinetics that diffuse in a part of the reactor volume. From the point of view of hydrodynamics activation, the discharge phases induce thermal shock waves and the storage of vibrational energy which relaxes into thermal form only during the post-discharge phase. Furthermore, the glow corona discharges that persist during the post-discharge phases induce the so called electri...

  2. 110 C thermoluminescence glow peak of quartz – A brief review

    Indian Academy of Sciences (India)

    be due to nuclear weapons explosions, nuclear reactor accident or any event which results in unintended radiation release. Retrospective dosimetry, the conventional term used for this measurement, has been effectively undertaken for doses rang- ing from ~ few mGy to few Gy using the 110◦C glow peak of quartz. The high.

  3. I'm sexy and I glow it: female ornamentation in a nocturnal capital breeder.

    Science.gov (United States)

    Hopkins, Juhani; Baudry, Gautier; Candolin, Ulrika; Kaitala, Arja

    2015-10-01

    In many species, males rely on sexual ornaments to attract females. Females, by contrast, rarely produce ornaments. The glow-worm (Lampyris noctiluca) is an exception where wingless females glow to attract males that fly in search of females. However, little is known about the factors that promote the evolution of female ornaments in a sexual selection context. Here, we investigated if the female ornament of the glow-worm is a signal of fecundity used in male mate choice. In support of this, we found brightness to correlate with female fecundity, and males to prefer brighter dummy females. Thus, the glow emitted by females is a reliable sexual signal of female fecundity. It is likely that male preference for the fecundity-indicating ornament has evolved because of large variation among females in fecundity, and because nocturnal males cannot directly assess female size and fecundity. These results indicate that female ornamentation may evolve in capital breeders (i.e. those in which stored resources are invested in reproduction) when females vary significantly in fecundity and this variation cannot be assessed directly by males. © 2015 The Author(s).

  4. Effect Of Pre-Heat Temperature On The Tl Glow Curve Of Fused ...

    African Journals Online (AJOL)

    Fused quartz obtained from SPI laboratories in West Chester USA was studied extensively for possibility of the application of as a TL detector using Victorreen TL reader model 2800M at the Center for Energy Research and Development, O.A.U., Ile- Ife. Results have shown that the maximum of the peak 1 of the glow curve ...

  5. Optimization of hollow cathode discharge electrode for damage free remote plasma removal process for semiconductor manufacturing

    Science.gov (United States)

    Cho, Tae S.; Han, Qing; Yang, Dongqing; Park, Soonam; Lubomirsky, Dima; Venkataraman, Shankar

    2016-05-01

    Cone-shaped hollow cathode electrode configuration for a damage free remote plasma removal process has been optimized for given pressures based on Paschen characteristic curves, voltage-current characteristics and time-resolved discharge observations as well as oxide film removal performances. Remote plasmas have been generated in two types of cone-shaped electrodes with mixtures of He, NF3, and NH3 for pressure range of 1-30 Torr. Paschen characteristic curves and voltage-current (V-I) characteristics define an operating pressure for low breakdown voltage and the hollow cathode effect to minimize the particles. Sinusoidal voltage waveform and asymmetry electrode configuration alternate the glow discharge and hollow cathode discharge modes in a cycle. The current and infrared emission intensity from the glow discharge increases together for both cone-shaped electrodes with increasing pressure, whereas the hollow cathode discharge plasma emits strong infrared only when pD condition is satisfied. For the wide cone electrode configuration, high voltage operation at higher pressure results in particle contamination on the processed wafer by high energy ion bombardment. Operating at optimum pressure for a given electrode configuration shows faster oxide etch rate with better uniformity over a whole 300 mm wafer.

  6. Characterization of Light at Night Data from Select SkyGlowNet Nodes

    Science.gov (United States)

    Flurchick, K. M.; Deal, S.; Foster, C.

    2013-05-01

    Internet-enabled sky brightness meters (iSBMs) that continuously record and log sky brightness at the zenith have been installed at the prototype nodes of a network called SkyGlowNet. Also logged are time and weather information. These data are polled at a user-defined frequency, typically about every 45 seconds. Although the SkyGlowNetdata are used for various professional scientific studies, they are also useful for independent student research projects. In this case, the data are uploaded to the SkyGlowNetwebsite, initially to a proprietary area where the data for each institution are embargoed for one or two semesters as students conduct research projects with their data. When released from embargo, the data are moved to another area where they can be accessed by all SkyGlowNet participants. In this paper, we describe a student project in which the data collected at two SkyGlowNet sites are characterized. The data streams are parsed into homogenous segments and statistical tools are employed to describe variations observed in the data values. We demonstrate how to differentiate between natural phenomena and the effects of artificial lighting on the brightness of the night sky. In our poster we show how these effects compare between sites as separate as Arizona and North Carolina. We also have experimented with the development of statistical metrics that are used to help categorize sky brightness on select nights, and can nearly automatically provide a characterization of the quality of the night sky for astronomical purposes.

  7. Blood donors' helping behavior is driven by warm glow: more evidence for the blood donor benevolence hypothesis.

    Science.gov (United States)

    Ferguson, Eamonn; Taylor, Michael; Keatley, David; Flynn, Niall; Lawrence, Claire

    2012-10-01

    The benevolence hypothesis (both donor and recipient gain) suggests that blood donors, compared to non-blood donors have a general altruistic motivational preference based on warm glow (i.e., "I donate because it makes me feel good"). With objective behavioral economics tests of altruism and warm-glow giving, this paper offers the first direct experimental test of this hypothesis. The prediction that blood donors will be motivated in general by warm glow was compared to predictions from other theoretical models: strong reciprocity and empathy. Four experiments and one prospective study examined blood donors' and nondonors' motivations for general charitable giving and blood donation. Variants of the dictator game (DG; a charity DG [CDG] and a warm-glow version of a CDG) were used to provide objective measures of altruism. Blood donors gave less than nondonors on the CDG, but gave more on the warm-glow version. Blood donors' actual donations (in the CDGs and blood donation) were associated with feelings of warm glow. There was no evidence that blood donors were motivated by strong reciprocity or empathic concerns. This paper offers objective behavioral evidence that blood donors' charitable giving and blood donation, compared to non-blood donors, is more strongly motivated by warm glow. This provides additional support for the benevolence hypothesis of blood donation. © 2012 American Association of Blood Banks.

  8. Risk factors for treatment failure with antiosteoporosis medication: the global longitudinal study of osteoporosis in women (GLOW).

    Science.gov (United States)

    Díez-Pérez, Adolfo; Adachi, Jonathan D; Adami, Silvano; Anderson, Frederick A; Boonen, Steven; Chapurlat, Roland; Compston, Juliet E; Cooper, Cyrus; Gehlbach, Stephen H; Greenspan, Susan L; Hooven, Frederick H; LaCroix, Andrea Z; Nieves, Jeri W; Netelenbos, J Coen; Pfeilschifter, Johannes; Rossini, Maurizio; Roux, Christian; Saag, Kenneth G; Silverman, Stuart; Siris, Ethel S; Wyman, Allison; Rushton-Smith, Sophie K; Watts, Nelson B

    2014-01-01

    Antiosteoporosis medication (AOM) does not abolish fracture risk, and some individuals experience multiple fractures while on treatment. Therefore, criteria for treatment failure have recently been defined. Using data from the Global Longitudinal Study of Osteoporosis in Women (GLOW), we analyzed risk factors for treatment failure, defined as sustaining two or more fractures while on AOM. GLOW is a prospective, observational cohort study of women aged ≥55 years sampled from primary care practices in 10 countries. Self-administered questionnaires collected data on patient characteristics, fracture risk factors, previous fractures, AOM use, and health status. Data were analyzed from women who used the same class of AOM continuously over 3 survey years and had data available on fracture occurrence. Multivariable logistic regression was used to identify independent predictors of treatment failure. Data from 26,918 women were available, of whom 5550 were on AOM. During follow-up, 73 of 5550 women in the AOM group (1.3%) and 123 of 21,368 in the non-AOM group (0.6%) reported occurrence of two or more fractures. The following variables were associated with treatment failure: lower Short Form 36 Health Survey (SF-36) score (physical function and vitality) at baseline, higher Fracture Risk Assessment Tool (FRAX) score, falls in the past 12 months, selected comorbid conditions, prior fracture, current use of glucocorticoids, need of arms to assist to standing, and unexplained weight loss ≥10 lb (≥4.5 kg). Three variables remained predictive of treatment failure after multivariable analysis: worse SF-36 vitality score (odds ratio [OR] per 10-point increase, 0.85; 95% confidence interval [CI], 0.76-0.95; p = 0.004); two or more falls in the past year (OR, 2.40; 95% CI, 1.34-4.29; p = 0.011), and prior fracture (OR, 2.93; 95% CI, 1.81-4.75; p < 0.0001). The C statistic for the model was 0.712. Specific strategies for fracture prevention should therefore be

  9. Composition dependence of glow peak temperature in KCl{sub 1-x}Br{sub x} doped with divalent cations

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Salas, R [Departamento de Investigacion en FIsica, Universidad de Sonora, Apartado Postal 5-088 Hermosillo, Sonora, 83190 (Mexico); Aceves, R [Departamento de Investigacion en FIsica, Universidad de Sonora, Apartado Postal 5-088 Hermosillo, Sonora, 83190 (Mexico); RodrIguez-Mijangos, R [Departamento de Investigacion en FIsica, Universidad de Sonora, Apartado Postal 5-088 Hermosillo, Sonora, 83190 (Mexico); Riveros, H G [Instituto de FIsica, UNAM, Apartado Postal 20/364, Mexico, DF 01000, Mexico (Mexico); Duarte, C [Departamento de GeologIa, Universidad de Sonora, Rosales y Boulevard Luis E, Hermosillo, Sonora, 83000 (Mexico)

    2004-01-28

    Thermoluminescence measurements of {beta}-irradiated Eu{sup 2+} - and Ca{sup 2+} - doped KCl{sub 1-x}KBr{sub x} solid solutions excited at room temperature have been carried out to identify the effect of composition on the glow peaks. A typical glow peak has been distinguished for each composition. A linear dependence of its temperature on the composition x has been found. These results indicate that for divalent impurity-doped alkali halide solid solutions these glow peak temperatures are mostly dependent on the lattice constant of the host than on the size of the anion or impurity cation.

  10. Immobilization of surface active compounds on polymer supports using glow discharge processess. 1. Sodium dodecyl sulfate on poly(propylene)

    NARCIS (Netherlands)

    Terlingen, J.G.A.; Terlingen, Johannes G.A.; Feijen, Jan; Hoffman, Allan S.

    1993-01-01

    A new method has been developed in which a reversibly adsorbed layer of a surfactant (sodium dodecyl sulfate, SDS) is covalently immobilized in one step onto a hydrophobic substrate (poly(propylene), PP) by applying an argon plasma treatment. The adsorption of SDS from aqueous solutions onto PP

  11. Development of Efficient Models of Corona Discharges Around Tall Structures

    Science.gov (United States)

    Tucker, J.; Pasko, V. P.

    2012-12-01

    This work concerns with numerical modeling of glow corona and sreamer corona discharges that occur near tall ground structures under thunderstorm conditions. Glow corona can occur when ambient electric field reaches modest values on the order of 0.2 kV/cm and when the electric field near sharp points of ground structure rises above a geometry dependent critical field required for ionization of air. Air is continuously ionized in a small region close to the surface of the structure and ions diffuse out into the surrounding air forming a corona. A downward leader approaching from a thundercloud causes a further increase in the electric field at the ground level. If the electric field rises to the point where it can support formation of streamers in air surrounding the tall structure, a streamer corona flash, or series of streamer corona flashes can be formed significantly affecting the space charge configuration formed by the preceding glow corona. The streamer corona can heat the surrounding air enough to form a self-propagating thermalized leader that is launched upward from the tall structure. This leader travels upward towards the thundercloud and connects with the downward approaching leader thus causing a lightning flash. Accurate time-dependent modeling of charge configuration created by the glow and streamer corona discharges around tall structure is an important component for understanding of the sequence of events leading to lightning attachment to the tall structure. The present work builds on principal modeling ideas developed previously in [Aleksandrov et al., J. Phys. D: Appl. Phys., 38, 1225, 2005; Bazelyan et al., Plasma Sources Sci. Technol., 17, 024015, 2008; Kowalski, E. J., Honors Thesis, Penn State Univ., University Park, PA, May 2008; Tucker and Pasko, NSF EE REU Penn State Annual Res. J., 10, 13, 2012]. The non-stationary glow and streamer coronas are modeled in spherical geometry up to the point of initiation of the upward leader. The model

  12. Translational, rotational, vibrational and electron temperatures of a gliding arc discharge

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Ehn, Andreas; Gao, Jinlong

    2017-01-01

    Translational, rotational, vibrational and electron temperatures of a gliding arc discharge in atmospheric pressure air were experimentally investigated using in situ, non-intrusive optical diagnostic techniques. The gliding arc discharge was driven by a 35 kHz alternating current (AC) power source...... and operated in a glow-type regime. The two-dimensional distribution of the translational temperature (Tt) of the gliding arc discharge was determined using planar laser-induced Rayleigh scattering. The rotational and vibrational temperatures were obtained by simulating the experimental spectra. The OH A–X (0......, 0) band was used to simulate the rotational temperature (Tr) of the gliding arc discharge whereas the NO A–X (1, 0) and (0, 1) bands were used to determine its vibrational temperature (Tv). The instantaneous reduced electric field strength E/N was obtained by simultaneously measuring...

  13. Properties of thermoluminescence glow curves from tunneling recombination processes in random distributions of defects

    Energy Technology Data Exchange (ETDEWEB)

    Kitis, George [Nuclear Physics Laboratory, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Pagonis, Vasilis, E-mail: vpagonis@mcdaniel.edu [Physics Department, McDaniel College, Westminster, MD 21157 (United States)

    2014-09-15

    Localized electronic recombination processes in donor–acceptor pairs of luminescent materials have been recently modeled using a new kinetic model based on tunneling. Within this model, recombination is assumed to take place via the excited state of the donor, and nearest-neighbor recombinations take place within a random distribution of centers. An approximate semi-analytical version of the model has been shown to simulate successfully thermally and optically stimulated luminescence (TL and OSL), linearly modulated OSL (LM-OSL) and isothermal TL processes. This paper presents a detailed analysis of the geometrical properties of the TL glow curves obtained within three different published versions of the model. The dependence of the shape of the TL glow curves on the kinetic parameters of the model is examined by allowing simultaneous random variations of the parameters, within wide ranges of physically reasonable values covering several orders of magnitude. It is found that the TL glow curves can be characterized according to their shape factors μ{sub g}, as commonly done in TL theory of delocalized transitions. The values of the shape factor are found to depend rather weakly on the activation energy E and the frequency factor s, but they have a strong dependence on the parameter ρ′ which characterizes the concentration of acceptors in the model. It is also shown by simulation that both the variable heating rate and initial rise methods are applicable in this type of model and can yield the correct value of the activation energy E. However, the initial rise method of analysis for the semianalytical version of the model fails to yield the correct E value, since it underestimates the low temperature part of the TL glow curves. Two analytical expressions are given for the TL intensity, which can be used on an empirical basis for computerized glow curve deconvolution analysis (CGCD). - Highlights: • Detailed study of TL glow curves in a tunneling model for

  14. Surface charge measurements on different dielectrics in diffuse and filamentary barrier discharges

    Science.gov (United States)

    Tschiersch, R.; Nemschokmichal, S.; Bogaczyk, M.; Meichsner, J.

    2017-03-01

    Previously, we reported on the measurement of surface charges during the operation of barrier discharges (BDs) using the electro-optic Pockels effect of a bismuth silicon oxide (BSO) crystal. With the present work, the next milestone is achieved by making this powerful method accessible to various dielectrics which are typically used in BD configurations. The dynamics and spatial distribution of positive and negative surface charges were determined on optically transparent borosilicate glass, mono-crystalline alumina and magnesia, respectively, covering the BSO crystal. By variation of the nitrogen admixture to helium and the pressure between 500~\\text{mbar} and 1~\\text{bar} , both the diffuse glow-like BD and the self-stabilized discharge filaments were operated inside of a gas gap of 3~\\text{mm} . The characteristics of the discharge and, especially, the influence of the different dielectrics on its development were studied by surface charge diagnostics, electrical measurements and ICCD camera imaging. Regarding the glow-like BD, the breakdown voltage changes significantly by variation of the cathodic dielectric, due to the different effective secondary electron emission (SEE) coefficients. These material-specific SEE yields were estimated using Townsend’s criterion in combination with analytical calculations of the effective ionization coefficient in helium with air impurities. Moreover, the importance of the surface charge memory effect for the self-stabilization of discharge filaments was quantified by the recalculated spatio-temporal behavior of the gap voltage.

  15. Heart bypass surgery - minimally invasive - discharge

    Science.gov (United States)

    Minimally invasive direct coronary artery bypass - discharge; MIDCAB - discharge; Robot assisted coronary artery bypass - discharge; RACAB - discharge; Keyhole heart surgery - discharge; Coronary artery disease - MIDCAB discharge; CAD - ...

  16. Anticipated Guilt for not Helping and Anticipated Warm Glow for Helping are Differently Impacted by Personal Responsibility to Help

    OpenAIRE

    Arvid Erlandsson; Amanda Åsa Jungstrand; Daniel Vastfjall

    2016-01-01

    One important motivation for people behaving prosocially is that they want to avoid negative and obtain positive emotions. In the prosocial behavior literature however, the motivations to avoid negative emotions (e.g. guilt) and to approach positive emotions (e.g. warm glow) are rarely separated, and sometimes even aggregated into a single mood-management construct. The aim of this study was to investigate whether anticipated guilt if not helping and anticipated warm glow if helping are influ...

  17. Fading prediction in thermoluminescent materials using computerised glow curve deconvolution (CGCD)

    CERN Document Server

    Furetta, C; Weng, P S

    1999-01-01

    The fading of three different thermoluminescent (TL) materials, CaF sub 2 : Tm (TLD-300), manocrystalline LiF : Mg,Ti (DTG-4) and MgB sub 4 O sub 7 : Dy,Na has been studied at room temperature and at 50 deg. C of storage. The evolution as a function of the elapsed time of the whole glow curve as well as of the individual peaks has been analysed using the Computerised Glow Curve Deconvolution (CGCD) program developed at the NTHU. The analysis allows to predict the loss of the dosimetric information and to make any correction is necessary for using the TL dosimeters in practical applications. Furthermore, it is well demonstrated that using CGCD it is not necessary to anneal the peaks having a rapid fading to avoid, then, any interfering effect on the more stable peaks.

  18. Apocenter Glow in Eccentric Debris Disks: Implications for Fomalhaut and ɛ Eridani

    Science.gov (United States)

    Pan, Margaret; Nesvold, Erika R.; Kuchner, Marc J.

    2016-11-01

    Debris disks often take the form of eccentric rings with azimuthal asymmetries in surface brightness. Such disks are often described as showing “pericenter glow,” an enhancement of the disk brightness in regions nearest the central star. At long wavelengths, however, the disk apocenters should appear brighter than their pericenters: in the long-wavelength limit, we find that the apocenter/pericenter flux ratio scales as 1+e for disk eccentricity e. We produce new models of this “apocenter glow” to explore its causes and wavelength dependence and study its potential as a probe of dust grain properties. Based on our models, we argue that several far-infrared and (sub)millimeter images of the Fomalhaut and ɛ Eridani debris rings obtained with Herschel, JCMT, SHARC II, ALMA, and ATCA should be reinterpreted as suggestions or examples of apocenter glow. This reinterpretation yields new constraints on the disks’ dust grain properties and size distributions.

  19. SkyGlowNet: Multi-Disciplinary Independent Student Research in Environmental Light at Night Monitoring

    Science.gov (United States)

    Craine, B. L.; Craine, E. R.; Culver, R. B.; DeBenedetti, J. C.; Flurchick, K. M.

    2014-07-01

    SkyGlowNet uses Internet-enabled sky brightness meters (iSBM) to monitor sky brightness over school sites. The data are used professionally and in STEM outreach to study natural and artificial sources of sky brightness, light pollution, energy efficiency, and environmental and health impacts of artificial night lighting. The iSBM units are owned by participating institutions and managed by faculty or students via proprietary Internet links. Student data are embargoed for two semesters to allow students to analyze data and publish results, then they are moved to a common area where students from different institutions can collaborate. The iSBM units can be set to operate automatically each night. Their data include time, sky brightness, weather conditions, and other related parameters. The data stream can be viewed and processed online or downloaded for study. SkyGlowNet is a unique, multi-disciplinary, real science program aiding research for science and non-science students.

  20. XPS study on double glow plasma corrosion-resisting surface alloying layer

    Science.gov (United States)

    Ai, Jiahe; Xu, Jiang; He, Fei; Xie, Xishan; Xu, Zhong

    2003-02-01

    Double glow plasma corrosion-resisting surface alloying layer (SAL) formed on low carbon steel 1020 was studied by X-ray photoelectron spectroscopy (XPS) and other means. Results show that the passive film of the surface alloying layer after electrochemical test in 3.5% NaCl solution consists of Cr and Fe oxide such as CrO 3, Cr 2O 3, Fe 2O 3 and FeO and metallic Ni and Mo, and it attributes to the fact that a continuous and compact corrosion-resisting surface alloying layer with rich Cr, Ni and Mo was formed on the surface of steel 1020 so as to increase its corrosion resistance greatly. Therefore, double glow plasma technique will be widely used in corrosion-resisting surface science.

  1. Comparison of electrical and optical characteristics in gas-phase and gas-liquid phase discharges

    Science.gov (United States)

    Qazi, H. I. A.; Nie, Qiu-Yue; Li, He-Ping; Zhang, Xiao-Fei; Bao, Cheng-Yu

    2015-12-01

    This paper presents an AC-excited argon discharge generated using a gas-liquid (two-phase) hybrid plasma reactor, which mainly consists of a powered needle electrode enclosed in a conical quartz tube and grounded deionized water electrode. The discharges in the gas-phase, as well as in the two-phase, exhibit two discharge modes, i.e., the low current glow-like diffuse mode and the high current streamer-like constrict mode, with a mode transition, which exhibits a negative resistance of the discharges. The optical emission spectral analysis shows that the stronger diffusion of the water vapor into the discharge region in the two-phase discharges boosts up the generation of OH (A-X) radicals, and consequently, leads to a higher rotational temperature in the water-phase plasma plume than that of the gas-phase discharges. Both the increase of the power input and the decrease of the argon flow rate result in the increase of the rotational temperature in the plasma plume of the water-phase discharge. The stable two-phase discharges with a long plasma plume in the water-phase under a low power input and gas flow rate may show a promising prospect for the degradation of organic pollutants, e.g., printing and dyeing wastewater, in the field of environmental protection.

  2. Aligned Carbon Nanotubes Array by DC Glow Plasma Etching for Supercapacitor

    Directory of Open Access Journals (Sweden)

    Yongfeng Luo

    2013-01-01

    Full Text Available To open the end of carbon nanotubes and make these ends connect with functional carboxyl group, aligned carbon nanotubes (CNTs arrays was etched by DC glow oxygen-argon plasma. With these open-ended carbon nanotubes array as electrode materials to build supercapacitor, we found that the capacity (32.2 F/g increased significantly than that of pure carbon nanotubes (6.7 F/g.

  3. Urethral discharge culture

    Science.gov (United States)

    Culture of urethral discharge; Genital exudate culture; Culture - genital discharge or exudate ... 2015:chap 109. Craft AC, Woods GL. Specimen collection and handling for diagnosis of infectious diseases. In: ...

  4. 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 ...

  5. Hysterectomy - laparoscopic - discharge

    Science.gov (United States)

    ... a shower the day after surgery. If tape strips were used to close your skin, they should ... cancer Endometriosis Hysterectomy Uterine fibroids Patient Instructions Hysterectomy - abdominal - discharge Hysterectomy - vaginal - discharge Review Date 2/18/ ...

  6. Dynamics of plasma electrode coupling in fluorescent lamp discharges

    Science.gov (United States)

    Garner, R.

    2008-07-01

    A time dependent model of a low pressure, mercury-rare gas discharge with thermionic electrode is presented. The model is applicable to ac-operated fluorescent lamps, which is the focus of this work. The model describes a one-dimensional negative glow plasma that is bounded on one side by a thermionic electrode and a sheath, and on the other by a positive column plasma. The electrode/sheath component of the model, together with the mutually interacting negative glow plasma, allows for self-consistent calculation of the electrode sheath potential. The model describes a smooth transition in the plasma parameters from electrode to positive column and thus reveals the spatial extent of the influence of the electrode and sheath processes. A detailed description of the model is presented, as well as results of calculations pertaining to a standard fluorescent lamp. Also shown are measurements from a 2 mm interferometer and an internal floating probe, both of which compare favourably with the calculations.

  7. Dynamics of plasma-electrode coupling in fluorescent lamp discharges

    Energy Technology Data Exchange (ETDEWEB)

    Garner, R [Central Research and Services Laboratory, OSRAM SYLVANIA, 71 Cherry Hill Drive, Beverly, MA 01915 (United States)], E-mail: richard.garner@sylvania.com

    2008-07-21

    A time dependent model of a low pressure, mercury-rare gas discharge with thermionic electrode is presented. The model is applicable to ac-operated fluorescent lamps, which is the focus of this work. The model describes a one-dimensional negative glow plasma that is bounded on one side by a thermionic electrode and a sheath, and on the other by a positive column plasma. The electrode/sheath component of the model, together with the mutually interacting negative glow plasma, allows for self-consistent calculation of the electrode sheath potential. The model describes a smooth transition in the plasma parameters from electrode to positive column and thus reveals the spatial extent of the influence of the electrode and sheath processes. A detailed description of the model is presented, as well as results of calculations pertaining to a standard fluorescent lamp. Also shown are measurements from a 2 mm interferometer and an internal floating probe, both of which compare favourably with the calculations.

  8. An Investigation of LED Street Lighting's Impact on Sky Glow

    Energy Technology Data Exchange (ETDEWEB)

    Kinzey, Bruce R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Perrin, Tess E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Miller, Naomi J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kocifaj, Miroslav [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Aube, Martin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lamphar, Hector A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-04-25

    A significant amount of public attention has recently focused on perceived impacts of converting street lighting from incumbent lamp-based products to LED technology. Much of this attention pertains to the higher content of short wavelength light (commonly referred to as "blue light") of LEDs and its attendant influences on sky glow (a brightening of the night sky that can interfere with astronomical observation and may be associated with a host of other issues). The complexity of this topic leads to common misunderstandings and misperceptions among the public, and for this reason the U.S. Department of Energy Solid-State Lighting Program embarked on a study of sky glow using a well-established astronomical model to investigate some of the primary factors influencing sky glow. This report details the results of the investigation and attempts to present those results in terms accessible to the general lighting community. The report also strives to put the results into a larger context, and help educate interested readers on various topics relevant to the issues being discussed.

  9. The role of electronic mechanisms in surface erosion and glow phenomena

    Science.gov (United States)

    Haglund, Richard F., Jr.

    1987-01-01

    Experimental studies of desorption induced by electronic transitions (DIET) are described. Such studies are producing an increasingly complete picture of the dynamical pathways through which incident electronic energy is absorbed and rechanneled to produce macroscopic erosion and glow. These mechanistic studies can determine rate constants for erosion and glow processes in model materials and provide valuable guidance in materials selection and development. Extensive experiments with electron, photon, and heavy particle irradiation of alkali halides and other simple model materials have produced evidence showing that: (1) surface erosion, consisting primarily in the ejection or desorption of ground-state neutral atoms, occurs with large efficiencies for all irradiated species; (2) surface glow, resulting from the radiative decay of desorbed atoms, likewise occurs for all irradiating species; (3) the typical mechanism for ground-state neutral desorption is exciton formation, followed by relaxation to a permanent, mobile electronic defect which is the precursor to bond-breaking in the surface or near-surface bulk of the material; and (4) the mechanisms for excited atom formation may include curve crossing in atomic collisions, interactions with surface defect or impurity states, or defect diffusion.

  10. Nurse-led discharge.

    Science.gov (United States)

    Page, Carole

    2010-12-01

    Delayed discharges have financial implications for hospital trusts and cause dissatisfaction for patients and their families. This article looks at nurse-led discharge pathways at Milton Keynes Hospital's ambulatory care unit. It explains how giving nurses the responsibility to discharge has improved the patient experience, made nurses more accountable and saved money for the trust.

  11. Electron and ion kinetics in a micro hollow cathode discharge

    Energy Technology Data Exchange (ETDEWEB)

    Kim, G J; Iza, F; Lee, J K [Electronics and Electrical Engineering Department, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of)

    2006-10-21

    Electron and ion kinetics in a micro hollow cathode discharge are investigated by means of two-dimensional axisymmetric particle-in-cell Monte Carlo collision simulations. Argon discharges at 10 and 300 Torr are studied for various driving currents. Electron and ion energy probability functions (IEPF) are shown at various times and locations to study the spatio-temporal behaviour of the discharge. The electron energy probability function (EEPF) evolves from the Druyvesteyn type in the early stages of the discharge into a two (or three) temperature distribution when steady state is reached. In steady state, secondary electrons accelerated across the cathode fall populate the high energy tail of the EEPF while the low energy region is populated by trapped electrons. The IEPF evolves from a Maxwellian in the negative glow (bulk) to a two temperature distribution on the cathode surface. The overpopulation of low energy ions near the cathode surface is attributed to a larger collision cross section for low energy ions and ionization within the cathode fall.

  12. Influence of the gas mixture radio on the correlations between the excimer XeCl emission and the sealed gas temperature in dielectric barrier discharge lamps

    CERN Document Server

    Xu Jin Zhou; Ren Zhao Xing

    2002-01-01

    For dielectric barrier discharge lamps filled with various gas mixture ratios, the correlations between the excimer XeCl emission and the sealed gas temperature have been founded, and a qualitative explication is presented. For gas mixture with chlorine larger than 3%, the emission intensity increases with the sealed gas temperature, while with chlorine about 2%, the emission intensity decreases with the increasing in the gas temperature, and could be improved by cooling water. However, if chlorine is less than 1.5%, the discharge appears to be a mixture mode with filaments distributed in a diffused glow-like discharge, and the UV emission is independent on the gas temperature

  13. Two-dimensional simulation of argon dielectric barrier discharge excited by a Gaussian voltage at atmospheric pressure

    Science.gov (United States)

    Xu, Yonggang; Wang, Jing; Li, Jing; Lei, Bingying; Tang, Jie; Wang, Yishan; Li, Yongfang; Zhao, Wei; Duan, Yixiang

    2017-04-01

    A two-dimensional self-consistent fluid model was employed to investigate the spatiotemporal characteristics of discharges in atmospheric pressure argon (Ar) dielectric barrier discharge driven by a Gaussian voltage. The simulation results show that a discharge with multiple current pulses occurs each half-cycle in the gas gap. A transition from the Townsend mode to the glow mode is observed with the increasing applied voltage each half-cycle at a lower driving frequency (7.5 kHz). It is also found that the glow mode survives all the discharge phases at a higher driving frequency (12.5 kHz and 40 kHz). The change in the discharge mode with the driving frequency mainly lies in the fact that a lot of charged particles created in the discharge gap have no enough time to drift and diffuse around, and then these particles are assembled in the discharge space at higher frequency. Additionally, the spatial distributions of the electron density indicate that a center-advantage discharge is ignited at the driving frequencies of interest, resulting in the radial non-uniformity of discharge because of the edge effects. However, this overall non-uniformity is weakened with the driving frequency increased to 40 kHz, at which concentric ring patterns are observed. These distinct behaviors are mainly attributed to the fact that many charged particles generated are trapped in the gas gap and then accumulated to make the extension along the radial direction due to the charged particles transport and diffusion, and that the effective overlapping of a large number of avalanches induced by the increased "seed" electron density with the driving frequency. Meanwhile, the surface charged particles accumulated on the dielectric barriers are also shown to play a role in the formation of the discharge structure.

  14. Kinetics of the Electric Discharge Pumped Oxygen-Iodine Laser

    Science.gov (United States)

    2011-09-01

    of the sustainer pulse is tailored to keep the discharge stable. In January 2007, OSU demonstrated a peak laser power of 0.28 W, using a pulser...controlled avalanche ionization, Applied Physics Letters, 22, p. 670, (1973). (57) Hill. A.E., The next generation of controlled avalanche discharge ...pressure oxygen pulsed discharge . Simple and quick method for temperature determination, J. Phys. D:Appl. Phys. 32, pp. 246-250, (1998). (71

  15. Chronic obstructive pulmonary disease - adults - discharge

    Science.gov (United States)

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

  16. Effect of co-morbidities on fracture risk: findings from the Global Longitudinal Study of Osteoporosis in Women (GLOW).

    Science.gov (United States)

    Dennison, Elaine M; Compston, Juliet E; Flahive, Julie; Siris, Ethel S; Gehlbach, Stephen H; Adachi, Jonathan D; Boonen, Steven; Chapurlat, Roland; Díez-Pérez, Adolfo; Anderson, Frederick A; Hooven, Frederick H; LaCroix, Andrea Z; Lindsay, Robert; Netelenbos, J Coen; Pfeilschifter, Johannes; Rossini, Maurizio; Roux, Christian; Saag, Kenneth G; Sambrook, Philip; Silverman, Stuart; Watts, Nelson B; Greenspan, Susan L; Premaor, Melissa; Cooper, Cyrus

    2012-06-01

    Greater awareness of the relationship between co-morbidities and fracture risk may improve fracture-prediction algorithms such as FRAX. We used a large, multinational cohort study (GLOW) to investigate the effect of co-morbidities on fracture risk. Women completed a baseline questionnaire detailing past medical history, including co-morbidity history and fracture. They were re-contacted annually to determine incident clinical fractures. A co-morbidity index, defined as number of baseline co-morbidities, was derived. The effect of adding the co-morbidity index to FRAX risk factors on fracture prevention was examined using chi-squared tests, the May-Hosmer test, c index and comparison of predicted versus observed fracture rates. Of 52,960 women with follow-up data, enrolled between October 2006 and February 2008, 3224 (6.1%) sustained an incident fracture over 2 years. All recorded co-morbidities were significantly associated with fracture, except for high cholesterol, hypertension, celiac disease, and cancer. The strongest association was seen with Parkinson's disease (age-adjusted hazard ratio [HR]: 2.2; 95% CI: 1.6-3.1; P<0.001). Co-morbidities that contributed most to fracture prediction in a Cox regression model with FRAX risk factors as additional predictors were: Parkinson's disease, multiple sclerosis, chronic obstructive pulmonary disease, osteoarthritis, and heart disease. Co-morbidities, as captured in a co-morbidity index, contributed significantly to fracture risk in this study population. Parkinson's disease carried a particularly high risk of fracture; and increasing co-morbidity index was associated with increasing fracture risk. Addition of co-morbidity index to FRAX risk factors improved fracture prediction. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Methane Incorporation into Liquid Fuel by Non-Equilibrium Plasma Discharges

    CERN Document Server

    Liu, Chong; Ji, Hai-Feng; Smith, Joshua; Rabinovich, Alexander; Dobrynin, Danil; Fridman, Alexander

    2016-01-01

    The conventional ways of processing natural gas into more efficient and economical fuels usually either have low conversion rate or low energy efficiency. In this work, a new approach of methane liquefaction is proposed. Instead of direct treatment of only natural gas, plasma activated methane is reacting with liquid fuel. In this way, methane molecules are directly incorporated onto liquid fuel to achieve liquefaction. Nanosecond-pulsed dielectric barrier discharge and atmospheric pressure glow discharge are used here to ensure no local heating in gas bubbles. Effects of both discharges on methane reaction with liquid fuel are investigated, mass and chemical changes in liquid are observed. Preliminary results show fixation of methane in liquid fuel.

  18. Improving Hospital Discharge Time

    Science.gov (United States)

    El-Eid, Ghada R.; Kaddoum, Roland; Tamim, Hani; Hitti, Eveline A.

    2015-01-01

    Abstract Delays in discharging patients can impact hospital and emergency department (ED) throughput. The discharge process is complex and involves setting specific challenges that limit generalizability of solutions. The aim of this study was to assess the effectiveness of using Six Sigma methods to improve the patient discharge process. This is a quantitative pre and post-intervention study. Three hundred and eighty-six bed tertiary care hospital. A series of Six Sigma driven interventions over a 10-month period. The primary outcome was discharge time (time from discharge order to patient leaving the room). Secondary outcome measures included percent of patients whose discharge order was written before noon, percent of patients leaving the room by noon, hospital length of stay (LOS), and LOS of admitted ED patients. Discharge time decreased by 22.7% from 2.2 hours during the preintervention period to 1.7 hours post-intervention (P discharge. Hospital LOS dropped from 3.4 to 3.1 days postintervention (P hospital was significantly lower in the postintervention period (6.9 ± 7.8 vs 5.9 ± 7.7 hours; P discharge time. The focus of institutions aspiring to tackle delays in the discharge process should be on adopting the core principles of Six Sigma rather than specific interventions that may be institution-specific. PMID:25816029

  19. Product analysis of partial discharge damage to oil-impregnated insulation paper

    Science.gov (United States)

    Yan, Jiaming; Liao, Ruijin; Yang, Lijun; Li, Jian; Liu, Bin

    2011-04-01

    Surface products of oil-impregnated insulation paper during the damage process caused by partial discharge (PD), as well as gas within the cavity, were studied. An optical microscope and a scanning electron microscope (SEM) were used to investigate surface morphology, while an infrared spectroscopy (IR) and an X-ray photoelectron spectroscopy (XPS) were used to study surface products and their components. The volume variation in cavity gas was also analyzed. Furthermore, gas constituents and their relevant contents were studied using a gas chromatography-mass spectrometer (GC-MS). The study results reveal the following: during the PD damage process, the total gas volume and the content of electronegative gasses alternately decline and increase, while discharge types alternate between pulse type and pseudo-glow type (or glow type); “surface droplets” and “crystalline solids” appear on the insulation surface one after another; surface droplets mainly consist of (Cdbnd O)-group-containing compounds, whereas crystalline solids are mainly carboxylic acids, with carboxyl groups also found in cellulose chains; and the discharge type related to the oxidization of decomposition products is the main factor that determines the state (liquid or solid) of the surface products.

  20. Mass spectrometric study of the kinetics of chemical reactions in tetrafluoroethylene initiated by a gas discharge

    Energy Technology Data Exchange (ETDEWEB)

    Zyn' , V.I.; Oparin, V.B.; Potapov, V.K.; Tuzov, L.S.

    1986-01-01

    In this investigation of the time dependence of the partial pressures of fluorohydrocarbons synthesized from tetrafluoroethylene in an atypical glow discharge, the mass spectrometric method was used. The product yield sequence in a state reactor was determined: C/sub 4/F/sub 8/, C/sub 3/F/sub 8/, C/sub 2/F/sub 6/, C/sub 4/F/sub 10/, CF/sub 4/. In the 6-80 Pa range the C/sub 2/F/sub 4/ decomposition rate does not depend on the initial monomer pressure. A kinetic model giving a good description of the experimental results is proposed.

  1. The Chemically Synthesized Ageladine A-Derivative LysoGlow84 Stains Lysosomes in Viable Mammalian Brain Cells and Specific Structures in the Marine Flatworm Macrostomum lignano

    Directory of Open Access Journals (Sweden)

    Thorsten Mordhorst

    2015-02-01

    Full Text Available Based on the chemical structure and the known chemical synthesis of the marine sponge alkaloid ageladine A, we synthesized the ageladine A-derivative 4-(naphthalene-2-yl-1H-imidazo[4,5-c]pyridine trifluoroacetate (LysoGlow84. The two-step synthesis started with the Pictet-Spengler reaction of histamine and naphthalene-2-carbaldehyde to a tetrahydropyridine intermediate, which was dehydrogenated with activated manganese (IV oxide to LysoGlow84. Structure and purity of the synthesized LysoGlow84 were confirmed by NMR spectroscopy and mass spectrometry. The fluorescence intensity emitted by LysoGlow84 depended strongly on the pH of the solvent with highest fluorescence intensity recorded at pH 4. The fluorescence maximum (at 315 nm excitation was observed at 440 nm. Biocompatibility of LysoGlow84 was investigated using cultured rat brain astrocytes and the marine flatworm Macrostomum lignano. Exposure of the astrocytes for up to 6 h to micromolar concentrations of LysoGlow84 did not compromise cell viability, as demonstrated by several viability assays, but revealed a promising property of this compound for staining of cellular vesicles. Conventional fluorescence microscopy as well as confocal scanning microscopy of LysoGlow84-treated astrocytes revealed co-localization of LysoGlow84 fluorescence with that of LysoTracker® Red DND-99. LysoGlow84 stained unclear structures in Macrostomum lignano, which were identified as lysosomes by co-staining with LysoTracker. Strong fluorescence staining by LysoGlow84 was further observed around the worms’ anterior gut and the female genital pore which were not counterstained by LysoTracker Red. Thus, LysoGlow84 is a new promising dye that stains lysosomes and other acidic compartments in cultured cells and in worms.

  2. The chemically synthesized ageladine A-derivative LysoGlow84 stains lysosomes in viable mammalian brain cells and specific structures in the marine flatworm Macrostomum lignano.

    Science.gov (United States)

    Mordhorst, Thorsten; Awal, Sushil; Jordan, Sebastian; Petters, Charlotte; Sartoris, Linda; Dringen, Ralf; Bickmeyer, Ulf

    2015-02-11

    Based on the chemical structure and the known chemical synthesis of the marine sponge alkaloid ageladine A, we synthesized the ageladine A-derivative 4-(naphthalene-2-yl)-1H-imidazo[4,5-c]pyridine trifluoroacetate (LysoGlow84). The two-step synthesis started with the Pictet-Spengler reaction of histamine and naphthalene-2-carbaldehyde to a tetrahydropyridine intermediate, which was dehydrogenated with activated manganese (IV) oxide to LysoGlow84. Structure and purity of the synthesized LysoGlow84 were confirmed by NMR spectroscopy and mass spectrometry. The fluorescence intensity emitted by LysoGlow84 depended strongly on the pH of the solvent with highest fluorescence intensity recorded at pH 4. The fluorescence maximum (at 315 nm excitation) was observed at 440 nm. Biocompatibility of LysoGlow84 was investigated using cultured rat brain astrocytes and the marine flatworm Macrostomum lignano. Exposure of the astrocytes for up to 6 h to micromolar concentrations of LysoGlow84 did not compromise cell viability, as demonstrated by several viability assays, but revealed a promising property of this compound for staining of cellular vesicles. Conventional fluorescence microscopy as well as confocal scanning microscopy of LysoGlow84-treated astrocytes revealed co-localization of LysoGlow84 fluorescence with that of LysoTracker® Red DND-99. LysoGlow84 stained unclear structures in Macrostomum lignano, which were identified as lysosomes by co-staining with LysoTracker. Strong fluorescence staining by LysoGlow84 was further observed around the worms' anterior gut and the female genital pore which were not counterstained by LysoTracker Red. Thus, LysoGlow84 is a new promising dye that stains lysosomes and other acidic compartments in cultured cells and in worms.

  3. Glow curve control o the maximum readout temperature: application to Li GR-200

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Ros, J.M.; Muniz, J.L. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain); Burg, B. van der; Delgado, A. [Technische Univ. Delft (Netherlands). Interfacultair Reactor Inst.

    1996-12-31

    The influence of the maximum readout temperature on the LiF GR-200 dose response was studied. A fast heating rate (8{sup o}C.s{sup -1}) and a new method to set the maximum readout temperature were employed for this study. The new method determines on each measurement the maximum temperature with reference to the position of the main TL peak. This is achieved through the on-line analysis of the glow curve during heating. The good measurement reproducibility attained by using this method and a previously described computerised method for TL evaluation is also presented. (author).

  4. Translational, rotational, vibrational and electron temperatures of a gliding arc discharge.

    Science.gov (United States)

    Zhu, Jiajian; Ehn, Andreas; Gao, Jinlong; Kong, Chengdong; Aldén, Marcus; Salewski, Mirko; Leipold, Frank; Kusano, Yukihiro; Li, Zhongshan

    2017-08-21

    Translational, rotational, vibrational and electron temperatures of a gliding arc discharge in atmospheric pressure air were experimentally investigated using in situ, non-intrusive optical diagnostic techniques. The gliding arc discharge was driven by a 35 kHz alternating current (AC) power source and operated in a glow-type regime. The two-dimensional distribution of the translational temperature (Tt) of the gliding arc discharge was determined using planar laser-induced Rayleigh scattering. The rotational and vibrational temperatures were obtained by simulating the experimental spectra. The OH A-X (0, 0) band was used to simulate the rotational temperature (Tr) of the gliding arc discharge whereas the NO A-X (1, 0) and (0, 1) bands were used to determine its vibrational temperature (Tv). The instantaneous reduced electric field strength E/N was obtained by simultaneously measuring the instantaneous length of the plasma column, the discharge voltage and the translational temperature, from which the electron temperature (Te) of the gliding arc discharge was estimated. The uncertainties of the translational, rotational, vibrational and electron temperatures were analyzed. The relations of these four different temperatures (Te>Tv>Tr >Tt) suggest a high-degree non-equilibrium state of the gliding arc discharge.

  5. Runaway Electron Preionized Diffuse Discharge and Its Impact on Plane Anode

    Science.gov (United States)

    Tarasenko, Victor; Erofeev, Michael; Ripenko, Vasilii; Shulepov, Mikhail; Baksht, Evgenii; National Research Tomsk Polytechnic University Collaboration; Institute of High Current Electronics Collaboration

    2016-09-01

    The spatial structure of a runaway electrons preionized diffuse discharge (REP DD) in nonuniform electric field and the influence of its plasma on the surface of a plane anode have been studied. In our experiments, we used a NPG-18/3500N high-voltage generator. The incident voltage had negative polarity, amplitude of 20 kV, and FWHM of 6 ns; the discharge current was up to 200 A. The discharge plasma was formed in nitrogen by applying high voltage pulses to the interelectrode gap which was varied between 2 and 9 mm. Under such conditions, the specific input power reached up to 10 MW/cm3. It is established that diffuse channel is the initial stage of the discharge radiation; then anode spot, channel with high glow intensity based on the anode spot and spark channel are consecutively formed. Spark formation finished within 10-15 ns after the onset of the discharge. Microstructure of spark and diffuse channels with anode spot autograph have been detected. The traces of such discharge represents itself an aggregation of up to 100 microcraters with dimeters of 5-100 micrometers. It was also shown that diffuse discharge does not leave erosive action on an anode surface or on its carbon cover. This work was supported by the Russian Science Foundation under the Grant Number 14-29-00052.

  6. Paediatric vaginal discharge

    African Journals Online (AJOL)

    Vaginal discharge in the prepubertal patient is a common symptom, and can be a source of distress for the caregiver and con- cern for the healthcare worker. Several factors predispose these patients to the development of recurrent vaginal discharge. Unless noticed by the caregiver, this problem can persist for long periods ...

  7. Graywater Discharges from Vessels

    Science.gov (United States)

    2011-11-01

    both sewage and graywater, or sewage collected from “ honey dipper” trucks, which may contain far less graywater, depending on the source (See... crystal clean effluent discharge. As a reference, Cruiseliners equipped with Scanship AWP systems has obtained continous discharge permits in Hawaii and

  8. Lithium battery discharge tests

    Science.gov (United States)

    Johnson, C. J.

    1980-01-01

    The long term discharge of a variety of lithium cells was characterized and the susceptibility of the cells to chemical variation during the slow discharge was tested. A shunt resistor was set across the terminals to monitor the voltage as a function of time. Failures were identified by premature voltage drops.

  9. 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.

  10. Sustainable Food & Sustainable Economics

    OpenAIRE

    Alvarez, Mavis Dora

    2012-01-01

    Cuba today is immersed in a very intense process of perfecting its agricultural production structures with the goal of making them more efficient and sustainable in their economic administration and in their social and environmental management. Agricultural cooperatives in Cuba have the responsibility of producing on 73% of the country's farmland. Their contributions are decisive to developing agricultural production and to ensuring more and better food for the population, in addition to redu...

  11. Silane Discharge Ion Chemistry.

    Science.gov (United States)

    Chatham, Robert Hood, III

    We have studied silane dc, rf and dc proximity discharges, using mass spectroscopic measurements of the positive ions as a detailed diagnostic for the type of discharge used to produce hydrogenated amorphous silicon solar photovoltaic cells. The properties and quality of these films depends in a very complex way upon the interactions of the many reactive neutral and ion species in the discharge. We have developed qualitative models of the ion chemical processes in these discharges from our measurements. Knowledge of the ion-molecule and electron-molecule collision cross sections is important to any attempt at understanding silane discharge chemistry. Consequently, we have measured the electron impact ionization cross sections for silane and disilane, and for comparison purposes also for methane and ethane. In addition, we have measured the rate coefficients for charge exchange reactions of He('+), Ne('+), and Ar('+) with silane, disilane, methane, and ethane, as these are important to understanding discharges in inert gas-silane mixtures. We have developed a detailed quantitative model of the cathode sheath region of a silane dc discharge, by extending the best recent calculation of the electron motion in the sheath to a self-consistent form which includes the ion motion. This model is used with comparison of silane dc discharge data to diagnose the ion chemistry occurring in the sheath region of silane dc discharge. The understanding of the discharge ion chemical processes that we have gained in this study represent an important step toward understanding the chemical and physical processes leading to film growth.

  12. High-energy molecular lasers self-controlled volume-discharge lasers and applications

    CERN Document Server

    Apollonov, V V

    2016-01-01

    This book displays the physics and design of high-power molecular lasers. The lasers described are self-controlled volume-discharge lasers. The book explains self-sustained discharge lasers, self-initiated discharge lasers and technical approaches to laser design. Important topics discussed are laser efficiency, laser beam quality and electric field homogeneity. The book contains many new innovative applications.

  13. Anticipated Guilt for not Helping and Anticipated Warm Glow for Helping are Differently Impacted by Personal Responsibility to Help

    Directory of Open Access Journals (Sweden)

    Arvid Erlandsson

    2016-09-01

    Full Text Available One important motivation for people behaving prosocially is that they want to avoid negative and obtain positive emotions. In the prosocial behavior literature however, the motivations to avoid negative emotions (e.g. guilt and to approach positive emotions (e.g. warm glow are rarely separated, and sometimes even aggregated into a single mood-management construct. The aim of this study was to investigate whether anticipated guilt if not helping and anticipated warm glow if helping are influenced similarly or differently when varying situational factors related to personal responsibility to help. Helping scenarios were created and pilot tests established that each helping scenario could be formulated both in a high-responsibility version and in a low-responsibility version. In Study 1 participants read high-responsibility and low-responsibility helping scenarios, and rated either their anticipated guilt if not helping or their anticipated warm glow if helping (i.e. separate evaluation. Study 2 was similar but here participants rated both their anticipated guilt if not helping and their anticipated warm glow if helping (i.e. joint evaluation. Anticipated guilt was clearly higher in the high-responsibility versions, but anticipated warm glow was unaffected (in Studies 1a and 1b, or even higher in the low-responsibility versions (Study 2. In Studies 3 (where anticipated guilt and warm glow were evaluated separately and 4 (where they were evaluated jointly, personal responsibility to help was manipulated within-subjects. Anticipated guilt was again constantly higher in the high-responsibility versions but for many types of responsibility-manipulations, anticipated warm glow was higher in the low-responsibility versions. The results suggest that we anticipate guilt if not fulfilling our responsibility but that we anticipate warm glow primarily when doing over and beyond our responsibility. We argue that future studies investigating motivations for

  14. Cosmic Glows

    OpenAIRE

    Scott, Douglas

    1999-01-01

    This is the obligatory Cosmic Microwave Background review. I discuss the current status of CMB anisotropies, together with some points on the related topic of the Far-Infrared Background. We have already learned a number of important things from CMB anisotropies. Models which are in good shape have: approximately flat geometry; cold dark-matter, plus something like a cosmological constant; roughly scale invariant adiabatic fluctuations; and close to Gaussian statistics. The constraints from t...

  15. Discharging test of electric power harness

    OpenAIRE

    Kawakita, Shiro; Takahashi, Masato; Kusawake, Hiroaki; Kuwajima, Saburo; 川北 史朗; 高橋 真人; 艸分 宏晶; 桑島 三郎

    2004-01-01

    The mechanism of electric power failure of a satellite has been researched. There are many reasons of loss of electric power of a satellite. Investigated was the power loss due to the sustained arc between primary power cables. The heat though arc tracking between the hot and return cables by secondary are discharge made them burn out. If the phenomenon were occurred in space, the satellite would suffer great damage.

  16. Discharge lamp technologies

    Science.gov (United States)

    Dakin, James

    1994-03-01

    This talk is an overview of discharge lamp technology commonly employed in general lighting, with emphasis on issues pertinent to lighting for plant growth. Since the audience is primarily from the plant growth community, and this begins the light source part of the program, we will start with a brief description of the discharge lamps. Challenges of economics and of thermal management make lamp efficiency a prime concern in controlled environment agriculture, so we will emphasize science considerations relating to discharge lamp efficiency. We will then look at the spectra and ratings of some representative lighting products, and conclude with a discussion of technological advances.

  17. 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

  18. Discharge lamp technologies

    Science.gov (United States)

    Dakin, James

    1994-01-01

    This talk is an overview of discharge lamp technology commonly employed in general lighting, with emphasis on issues pertinent to lighting for plant growth. Since the audience is primarily from the plant growth community, and this begins the light source part of the program, we will start with a brief description of the discharge lamps. Challenges of economics and of thermal management make lamp efficiency a prime concern in controlled environment agriculture, so we will emphasize science considerations relating to discharge lamp efficiency. We will then look at the spectra and ratings of some representative lighting products, and conclude with a discussion of technological advances.

  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. Brain injury - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000163.htm Brain injury - discharge To use the sharing features on ... know was in the hospital for a serious brain injury. At home, it will take time for ...

  1. Hypospadias repair - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000158.htm Hypospadias repair - discharge To use the sharing features on this page, please enable JavaScript. Your child had hypospadias repair to fix a birth defect in which ...

  2. Femur fracture repair - discharge

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000166.htm Femur fracture repair - discharge To use the sharing features on this page, please enable JavaScript. You had a fracture (break) in the femur in your leg. It ...

  3. Thyroid gland removal - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000293.htm Thyroid gland removal - discharge To use the sharing features ... surgery. This will make your scar show less. Thyroid Hormone Replacement You may need to take thyroid ...

  4. Breast radiation - discharge

    Science.gov (United States)

    Radiation - breast - discharge ... You may notice changes in the way your breast looks or feels (if you are getting radiation ... after treatment is over. The skin on your breast may become more sensitive or numb. Skin and ...

  5. 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 an abnormal formation of the rib ...

  6. Diverticulitis and diverticulosis - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000192.htm Diverticulitis and diverticulosis - discharge To use the sharing features ... JavaScript. You were in the hospital to treat diverticulitis. This is an infection of an abnormal pouch ( ...

  7. Lasik eye surgery - discharge

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000525.htm Lasik eye surgery - discharge To use the sharing features on this page, please enable JavaScript. Lasik eye surgery permanently changes the shape of the cornea ( ...

  8. 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 ...

  9. 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 ...

  10. 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 ...

  11. Epilepsy or seizures - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000128.htm Epilepsy or seizures - discharge To use the sharing features on this page, please enable JavaScript. You have epilepsy . People with epilepsy have seizures. A seizure is ...

  12. 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.

  13. Asthma - child - discharge

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000001.htm Asthma - child - discharge To use the sharing features on this ... care for your child. Take Charge of Your Child's Asthma at Home Make sure you know the ...

  14. 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 ...

  15. 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 ...

  16. Concussion - child - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000125.htm Concussion in children - discharge To use the sharing features ... enable JavaScript. Your child was treated for a concussion . This is a mild brain injury that can ...

  17. Multiple sclerosis - discharge

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000129.htm Multiple sclerosis - discharge To use the sharing features on this ... doctor has told you that you have multiple sclerosis (MS). This disease affects the brain and spinal ...

  18. Electronic discharge summaries.

    Science.gov (United States)

    Stetson, Peter D; Keselman, Alla; Rappaport, Daniel; Van Vleck, Tielman; Cooper, Mary; Boyer, Aurelia; Hripcsak, George

    2005-01-01

    Timely completion of Discharge Summaries is a requirement of high quality care. We developed a system for writing electronic Discharge Summaries. DSUM Writer has generated 2464 of 7349 total summaries (34%) and has paid for itself during its first 8 weeks in production. DSUM Writer is a component of a suite of tools (eNote) for electronic physician documentation used to support clinical care, billing and narrative analysis research.

  19. Discharge lamp technologies

    Energy Technology Data Exchange (ETDEWEB)

    Dakin, J. [GE Lighting, Cleveland, OH (United States)

    1994-12-31

    This talk is an overview of discharge lamp technology commonly employed in general lighting, with emphasis on issues pertinent to lighting for plant growth. Since the audience is primarily from the plant growth community, and this begins the light source part of the program, we will start with a brief description of the discharge lamps. Challenges of economics and of thermal management make lamp efficiency a prime concern in controlled environment agriculture, so we will emphasize science considerations relating to discharge lamp efficiency. We will then look at the spectra and ratings of some representative lighting products, and conclude with a discussion of technological advance. A general overview of discharge lighting technology can be found in the book of Waymouth (1971). A recent review of low pressure lighting discharge science is found in Dakin (1991). The pioneering paper of Reiling (1964) provides a good introduction to metal halide discharges. Particularly relevant to lighting for plant growth, a recent and thorough treatment of high pressure Na lamps is found in the book by deGroot and vanVliet (1986). Broad practical aspects of lighting application are thoroughly covered in the IES Lighting Handbook edited by Kaufman (1984).

  20. Go with the Glow: An Investigation into a 1960s Art Object with Phosphorescent Paint and its Treatment Possibilities

    NARCIS (Netherlands)

    Jansen, E.; Smit, I.; Dikken, D.J.; Korterik, J.; Offerhaus, H.; Bailão, A.; Henriques, F.; Bidarra, A.

    2015-01-01

    This paper discusses phosphorescent or ‘glow in the dark’ paint and its problems, charac- teristics and treatment possibilities, while using an artwork without title (1968, RMT, En- schede) by IMI Giese as case study. To understand the problems that can occur with this little examined material, it

  1. A Glowing Recommendation: A Project-Based Cooperative Laboratory Activity to Promote Use of the Scientific and Engineering Practices

    Science.gov (United States)

    Carmel, Justin H.; Ward, Joseph S.; Cooper, Melanie M.

    2017-01-01

    One of the most mystifying products on the market for people at any age is the glow stick: a plastic tube that, when snapped, creates a flood of bright, brilliantly colored light without the use of electricity or significant production of heat. In this case, the chemiluminescence reaction also provides an exciting phenomenon through which we can…

  2. Development of cold cathode arc discharge filament based multi-cusp H- ion source

    Science.gov (United States)

    Kumar, Rajnish; Ghodke, Dharmraj V.; Senecha, Vinod K.

    2017-08-01

    A cold cathode arc discharge filament based multicusp H- ion source (HNIS) has been developed using an innovative low power igniter system working in a glow discharge regime to achieve a longer lifetime of the filament. This HNIS is cesium-free and its experimental prototype generates a maximum H- ion beam (HNIB) current of 12 mA at 50 keV beam energy in pulse mode with a peak arc power of 27 kW using the triode extraction system. This article presents the results of initial commissioning of the HNIS and steering magnetic field used to separate out the co-extracted electrons from HNIB, verified through experiments and 3-D ion beam simulations.

  3. 2D simulations of short-pulsed dielectric barrier discharge xenon excimer lamp

    Energy Technology Data Exchange (ETDEWEB)

    Bogdanov, E.A.; Kudryavtsev, A.A. [St. Petersburg State University, St. Petersburg (Russian Federation); Arslanbekov, R.R. [CFD Research Corporation, Huntsville (United States)

    2006-07-01

    Self-consistent two-dimensional (2D) simulations of short-pulsed dielectric barrier discharge (DBD) in pure xenon have been performed. It is shown that during short current pulse the traversal inhomogeneity of the plasma parameters can be important only at the end of the current pulse as an edge effect close to the side walls. During the current pulse, the gap voltage drops until the ionization wave reaches the cathode so the current in the cathode sheath is the displacement current. This means that almost all of the absorbed power is deposited into excitation of xenon atoms and not to the ion heating in the cathode sheath as in the traditional glow discharges. This fact is one of the reasons of high efficiency of short-pulsed DBD. The developed model allows one to estimate the temporal position of the plasma-sheath boundary. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Towards a reduced chemistry module of a He-Ar-Cu hollow cathode discharge

    Science.gov (United States)

    Mihailova, D.; van Dijk, J.; Grozeva, M.; Degrez, G.; van der Mullen, J. J. A. M.

    2011-05-01

    This study is aimed at finding a reduced chemistry module for a hollow cathode discharge (HCD) excited in a He-Ar-Cu mixture. This enables us to construct lean and reliable models that can be used as a part of the design tool of HCDs. To this end estimative calculations and numerical simulations are performed under optimal conditions for lasing. An analysis of the species behaviour and reactions is made and as a result the model is simplified by means of reducing the number of species and reactions. The consequences of these reductions are justified by comparing the results of the simplified models with those of a more complete one. This study delivers a model that is chemically lean and thus, much less time consuming. It can be used in optimization studies to find the optimum in the plasma control parameter set of HCDs. The technique developed in this study for HCDs can be applied to glow discharges in general.

  5. Towards a reduced chemistry module of a He-Ar-Cu hollow cathode discharge

    Energy Technology Data Exchange (ETDEWEB)

    Mihailova, D; Van Dijk, J; Van der Mullen, J J A M [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven (Netherlands); Grozeva, M [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Bulgaria (Bulgaria); Degrez, G, E-mail: diana@epgmod.phys.tue.nl [Service de Mecanique des Fluides, Universite Libre de Bruxelles, 50 avenue F.D. Roosevelt, 1050 Bruxelles (Belgium)

    2011-05-18

    This study is aimed at finding a reduced chemistry module for a hollow cathode discharge (HCD) excited in a He-Ar-Cu mixture. This enables us to construct lean and reliable models that can be used as a part of the design tool of HCDs. To this end estimative calculations and numerical simulations are performed under optimal conditions for lasing. An analysis of the species behaviour and reactions is made and as a result the model is simplified by means of reducing the number of species and reactions. The consequences of these reductions are justified by comparing the results of the simplified models with those of a more complete one. This study delivers a model that is chemically lean and thus, much less time consuming. It can be used in optimization studies to find the optimum in the plasma control parameter set of HCDs. The technique developed in this study for HCDs can be applied to glow discharges in general.

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

    Science.gov (United States)

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

    2017-11-01

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

  7. Sustainable agriculture

    National Research Council Canada - National Science Library

    Lichtfouse, Eric

    2009-01-01

    ... : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 9 Part I CLIMATE CHANGE Soils and Sustainable Agriculture: A Review : : : : : : : : : : : : : : : : : : : : : : : : : : Rattan Lal 15 Soils and Food Sufficiency...

  8. Application of an atomic oxygen beam facility to the investigation of shuttle glow chemistry

    Science.gov (United States)

    Arnold, G. S.; Peplinski, D. R.

    1985-09-01

    A facility for the investigation of the interactions of energetic atomic oxygen with solids is described. The facility is comprised of a four chambered, differentially pumped molecular beam apparatus which can be equipped with one of a variety of sources of atomic oxygen. The primary source is a dc arc heated supersonic nozzle source which produces a flux of atomic oxygen in excess of 10 to the 15th power sq cm/sec at the target, at a velocity of 3.5 km/sec. Results of applications of this facility to the study of the reactions of atomic oxygen with carbon and polyimide films are briefly reviewed and compared to data obtained on various flights of the space shuttle. A brief discussion of possible application of this facility to investigation of chemical reactions which might contribute to atmosphere induced vehicle glow is presented.

  9. Sustainable Marketing

    NARCIS (Netherlands)

    Dam, van Y.K.

    2017-01-01

    In this article, three different conceptions of sustainable marketing are discussed and compared. These different conceptions are referred to as social, green, and critical sustainable marketing. Social sustainable marketing follows the logic of demand-driven marketing management and places the

  10. "Ictal" lateralized periodic discharges.

    Science.gov (United States)

    Sen-Gupta, Indranil; Schuele, Stephan U; Macken, Micheal P; Kwasny, Mary J; Gerard, Elizabeth E

    2014-07-01

    Whether lateralized periodic discharges (LPDs) represent ictal or interictal phenomena, and even the circumstances in which they may represent one or the other, remains highly controversial. Lateralized periodic discharges are, however, widely accepted as being ictal when they are time-locked to clinically apparent symptoms. We sought to investigate the characteristics of "ictal" lateralized periodic discharges (ILPDs) defined by time-locked clinical symptoms in order to explore the utility of using this definition to dichotomize LPDs into "ictal" and "nonictal" categories. Our archive of all continuous EEG (cEEG) reports of adult inpatients undergoing prolonged EEG monitoring for nonelective indications between 2007 and 2011 was searched to identify all reports describing LPDs. Lateralized periodic discharges were considered ILPDs when they were reported as being consistently time-locked to clinical symptoms; LPDs lacking a clear time-locked correlate were considered to be "nonictal" lateralized periodic discharges (NILPDs). Patient charts and available neuroimaging studies were also reviewed. Neurophysiologic localization of LPDs, imaging findings, presence of seizures, discharge outcomes, and other demographic factors were compared between patients with ILPDs and those with NILPDs. p-Values were adjusted for false discovery rate (FDR). One thousand four hundred fifty-two patients underwent cEEG monitoring at our institution between 2007 and 2011. Lateralized periodic discharges were reported in 90 patients, 10 of whom met criteria for ILPDs. Nine of the patients with ILPDs demonstrated motor symptoms, and the remaining patient experienced stereotyped sensory symptoms. Ictal lateralized periodic discharges had significantly increased odds for involving central head regions (odds ratio [OR]=11; 95% confidence interval [CI]=2.16-62.6; p=0.018, FDR adjusted), with a trend towards higher proportion of lesions involving the primary sensorimotor cortex (p=0.09, FDR

  11. Efficacy and safety of once-daily NVA237 in patients with moderate-to-severe COPD: the GLOW1 trial

    Directory of Open Access Journals (Sweden)

    D'Urzo Anthony

    2011-12-01

    Full Text Available Abstract Background NVA237 is a once-daily dry-powder formulation of the long-acting muscarinic antagonist glycopyrronium bromide in development for the treatment of chronic obstructive pulmonary disease (COPD. The glycopyrronium bromide in COPD airways clinical study 1 (GLOW1 evaluated the efficacy, safety and tolerability of NVA237 in patients with moderate-to-severe COPD. Methods Patients with COPD with a smoking history of ≥ 10 pack-years, post-bronchodilator forced expiratory volume in 1 second (FEV1 1/forced vital capacity 1 antagonists permitted in patients stabilized on them prior to study entry. The primary outcome measure was trough FEV1 at Week 12. Results A total of 822 patients were randomized to NVA237 (n = 552 or placebo (n = 270. Least squares mean (± standard error trough FEV1 at Week 12 was significantly higher in patients receiving NVA237 (1.408 ± 0.0105 L, versus placebo (1.301 ± 0.0137 L; treatment difference 108 ± 14.8 mL, p 1 were apparent at the end of Day 1 and sustained through Week 26. FEV1 was significantly improved in the NVA237 group versus placebo throughout the 24-hour periods on Day 1 and at Weeks 12 and 26, and at all other visits and timepoints. Transition dyspnoea index focal scores and St. George's Respiratory Questionnaire scores were significantly improved with NVA237 versus placebo at Week 26, with treatment differences of 1.04 (p Conclusions Once-daily NVA237 was safe and well tolerated and provided rapid, sustained improvements in lung function, improvements in dyspnoea, and health-related quality of life, and reduced the risk of exacerbations and the use of rescue medication. Trial registration ClinicalTrials.gov: NCT01005901

  12. High Sensitive Distinction of Discharge in Air by Daubechies Wavelet Transform

    Science.gov (United States)

    Yamada, Ioya; Kubota, Hisashi; Inui, Akifumi; Kawaguchi, Yoshihiro

    If partial discharge occurs in high voltage apparatus, it is unfavorable in view point of its insulation reliability, because they might develop into its insulation degradation or its electrical breakdown. In order to raise the insulation reliability of an apparatus, it is important to detect a minute partial discharge with sufficient sensitivity, especially suppressing background noise. This paper deals with the waveform processing technology by the Daubechies wavelet transform to make relief of the partial discharge signal from a measured noise-containing signal. On this basic idea, here is discussed that the optimal Daubechies order and its level have a close relation with the detection impedance and the sampling interval of the measured signal. Since the partial discharge waveform measured with the detection impedance of parallel circuits of RLC tuned into a damped oscillatory pulse, it has been demonstrated that the Daubechies wavelet transform is effective in discriminating the partial discharge signal from the measured noise-containing signal. Moreover, by choosing suitably the Daubechies order and its level applied to the measured data, it has been clarified that even a minute glow corona which have been masked by the background noise, and also the streamer corona turns into clear appearance on the transformed wave with sufficient sensitivity.

  13. Physical and chemical properties of low-pressure argon-chlorine dielectric barrier discharge

    Science.gov (United States)

    Barjasteh, Azadeh; Eslami, Esmaeil

    2016-03-01

    The influence of adding chlorine on the characteristics of a dielectric barrier discharge in Argon is investigated on the basis of a one-dimensional fluid model. The spatio-temporal characteristics of the discharge are obtained by applying a sinusoidal voltage with a frequency and amplitude of 7 kHz and 350 V, respectively. The study shows that the discharge has a homogeneous feature across the electrodes and has only one current pulse per half cycle of the applied voltage. The calculated electric field and electric potential as well as species number densities indicated that the discharge is in glow mode, and adding chlorine as electronegative gas up to 50% does not change its mode. It is observed that the most abundant negative species are C l - ions even in low additive chlorine. As a result, the maximum of plasma electronegativity takes place at 30% amounts of chlorine additive. The study of plasma radiations on the discharge gap shows that the main spontaneous emissions are observed at the wavelengths of 128.5 nm and 258 nm due to de-excitation of A r C l * and C l2 * molecules, respectively. Between different Ar/Cl2 mixtures, 0.99 A r - 0.01 C l 2 has the nearly uniform radiation in the positive column region.

  14. 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

  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...LABORATORY-TYPE DETECTORS SHOULD BE USED. IN SUMMARY, CHARACTERIS- TICS TO CONSIDER IN SELECTING AN ELECTROSTATIC DETECTOR ARE: o SENSITIVITY (MINIMUM

  16. ACL reconstruction - discharge

    Science.gov (United States)

    ... have redness, pain, swelling, or yellowish discharge from your incisions. You have a temperature higher than 101°F (38.3°C). ... W, Amy E, Sepulveda F. Anterior cruciate ligament tear. In: Frontera WR, Silver JK, Rizzo TD, eds. ...

  17. 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,…

  18. Low-voltage pulsed plasma discharges inside water using a bubble self-generating parallel plate electrode with a porous ceramic

    Science.gov (United States)

    Muradia, Sonia; Nagatsu, Masaaki

    2013-04-01

    Characteristics of pulsed bubbles discharges in water were investigated using parallel punched plate electrodes with a porous thin ceramic plate inserted between two metal plates. The micro-bubbles were generated just beneath the porous ceramic plate by flowing gas through it. The transition from spiky dielectric barrier discharges to pulsed glow discharges enables efficient bubble discharges at a relatively low voltage of 1.8 ˜ 4.0 kV of the 5 kHz square-waves with a pulse-width of about 750 ns. With 80% Ar and 20% O2 mixture gas at 4.0 kV, the 50 mg/l Indigo Carmine aqueous solution was efficiently decolorized within about 3 min.

  19. Sustainable Disruptions

    DEFF Research Database (Denmark)

    Friis, Silje Alberthe Kamille; Kjær, Lykke Bloch

    2016-01-01

    Since 2012 the Sustainable Disruptions (SD) project at the Laboratory for Sustainability at Design School Kolding (DK) has developed and tested a set of design thinking tools, specifically targeting the barriers to economically, socially, and environmentally sustainable business development....... The tools have been applied in practice in collaboration with 11 small and medium sized companies (SMEs). The study investigates these approaches to further understand how design thinking can contribute to sustainable transition in a business context. The study and the findings are relevant to organizations...... invested in the issue of sustainable business development, in particular the leaders and employees of SMEs, but also to design education seeking new ways to consciously handle and teach the complexity inherent in sustainable transformation. Findings indicate that the SD design thinking approach contributes...

  20. Computational sustainability

    CERN Document Server

    Kersting, Kristian; Morik, Katharina

    2016-01-01

    The book at hand gives an overview of the state of the art research in Computational Sustainability as well as case studies of different application scenarios. This covers topics such as renewable energy supply, energy storage and e-mobility, efficiency in data centers and networks, sustainable food and water supply, sustainable health, industrial production and quality, etc. The book describes computational methods and possible application scenarios.

  1. Characteristics of a micro-gap argon barrier discharge excited by a saw-tooth voltage at atmospheric pressure

    Science.gov (United States)

    Li, Xuechen; Zhang, Qi; Jia, Pengying; Chu, Jingdi; Zhang, Panpan; Dong, Lifang

    2017-03-01

    Using two water electrodes, a micro-gap dielectric barrier discharge excited by a saw-tooth voltage is investigated in atmospheric pressure argon. Through electrical and optical measurements, it is found that, at a lower driving frequency, a stepped discharge mode is obtained per half voltage cycle. Moreover, the duration and amplitude of the current plateau increase with the increase in the applied peak voltage. With the increase in the driving frequency, the stepped discharge mode transits into a pulsed one after a multi-peak mode. During this process, a diffuse discharge at a lower frequency transits into a filamentary one at a higher frequency. Temporal evolutions of the discharges are investigated axially based on fast photography. It is found that the stepped mode is in atmospheric pressure Townsend discharge (APTD) regime. However, there is a transition from APTD to atmospheric pressure glow discharge for the pulsed mode. Spectral intensity ratio of 391.4 nm to 337.1 nm is used to determine the averaged electron energy, which decreases with increasing peak voltage or driving frequency.

  2. Correlation between TL and OSL signals in KMgF{sub 3}:Ce{sup 3+}: Bleaching study of individual glow-peaks

    Energy Technology Data Exchange (ETDEWEB)

    Dallas, G.I., E-mail: gdallas@ipet.g [Archaeometry Laboratory, Cultural and Educational Technology Institute, R.C. Athena, 67100 Xanthi (Greece); Nuclear Engineering Laboratory, Democritus University of Thrace, 67100 Xanthi (Greece); Polymeris, G.S. [Archaeometry Laboratory, Cultural and Educational Technology Institute, R.C. Athena, 67100 Xanthi (Greece); Afouxenidis, D. [Nuclear Physics Laboratory, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Tsirliganis, N.C. [Archaeometry Laboratory, Cultural and Educational Technology Institute, R.C. Athena, 67100 Xanthi (Greece); Tsagas, N.F. [Nuclear Engineering Laboratory, Democritus University of Thrace, 67100 Xanthi (Greece); Kitis, G. [Nuclear Physics Laboratory, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

    2010-03-15

    KMgF{sub 3}:Ce{sup 3+} is an ultra sensitive Thermoluminescence (TL) material with a complex TL and OSL glow-curve structure. The aim of the present work is to attempt a one-to-one correspondence between specific TL glow-peaks and OSL components in KMgF{sub 3}:Ce{sup 3+}. The correlation study involves the deconvolution of the TL curves and the estimation of the bleaching decay constants for individual glow-peaks followed by the deconvolution of the LM-OSL curve using the estimated decay constants. It was found that the bleaching of each individual glow-peak takes place in three different rates; namely in a fast, medium and slow rate.

  3. Performance and Economics of Catalytic Glow Plugs and Shields in Direct Injection Natural Gas Engines for the Next Generation Natural Gas Vehicle Program: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Mello, J. P.; Bezaire, D.; Sriramulu, S.; Weber, R.

    2003-08-01

    Subcontractor report details work done by TIAX and Westport to test and perform cost analysis for catalytic glow plugs and shields for direct-injection natural gas engines for the Next Generation Natural Gas Vehicle Program.

  4. Sustainable transformation

    DEFF Research Database (Denmark)

    Andersen, Nicolai Bo

    This paper is about sustainable transformation with a particular focus on listed buildings. It is based on the notion that sustainability is not just a question of energy conditions, but also about the building being robust. Robust architecture means that the building can be maintained and rebuilt...... theoretical lenses. It is proposed that three parameters concerning the ꞌtransformabilityꞌ of the building can contribute to a more nuanced understanding of sustainable transformation: technical aspects, programmatic requirements and narrative value. It is proposed that the concept of ꞌsustainable...

  5. Mechanoluminescence glow curves of rare-earth doped strontium aluminate phosphors

    Science.gov (United States)

    Chandra, B. P.; Sonwane, V. D.; Haldar, B. K.; Pandey, S.

    2011-01-01

    The present paper reports the mechanoluminescence (ML) glow curves of rare-earth doped strontium aluminate phosphors. When Sr3Al2O6:Eu, Dy phosphor mixed in epoxy resin is compressed at a fixed pressing rate or fixed strain rate, its elastico ML (EML) intensity increases linearly with deformation time or pressure and attains a maximum value Im at the time tm, at which the deformation is stopped. Under the pressed condition, the decay time for fast decrease of EML after tm, gives the time-constant for stopping the cross-head of the testing machine used to deform the sample, and decay time for slow decrease of EML gives the lifetime of electrons in the shallow traps lying in the normal piezoelectric region of the crystals. When SrAl2O4:Eu phosphor mixed in resin is compressed at a fixed rate, then the EML intensity increases linearly with pressure and when the pressure is decreased at a fixed rate, then the EML intensity decreases exponentially with time, in which the decay time of EML is equal to the lifetime of electrons in the shallow traps lying in the normal piezoelectric region of the crystals. The EML intensity of SrAl2O4:Eu film excited by the impact stress, initially increases with time, attains a peak value and later on it decreases exponentially with time, in which the fast decay of EML intensity gives the decay time of impact stress and the decay time of the slow decrease of the EML intensity gives the lifetime of electrons in the shallow traps lying in the normal piezoelectric region of the crystals. The piezoelectrically-induced detrapping model is found to be suitable for the EML of rare-earth doped strontium aluminate phosphors. Expressions derived on the basis of the piezoelectrically-induced detrapping model are able to explain satisfactorily the characteristics of the EML of the phosphors. It is shown that several parameters of the phosphors can be determined from the ML glow curves.

  6. Searching for Lunar Horizon Glow with the LRO Star Tracker Cameras

    Science.gov (United States)

    Stubbs, T. J.; Wang, Y.; Glenar, D. A.; McClanahan, T. P.; Myers, D. C.; Keller, J. W.

    2015-12-01

    Apollo-era observations of "lunar horizon glow" phenomena have been interpreted as being due to the forward scattering of sunlight by very small dust grains above the lunar surface. High altitude lunar horizon glow (LHG) seen in coronal photographs taken above orbital sunset during Apollo 15 is consistent with a population of exospheric dust grains with radii of ≈0.1 μm extending to altitudes of ≈10 km; while near-surface LHG observed by the TV cameras aboard a few of the Surveyor landers is consistent with dust grains with radii of ≈5 μm within about a meter of the surface. More recent searches have been undertaken for high altitude LHG, or the associated dust population, using the Clementine star tracker cameras (sensitive to visible and near-IR), the Lyman Alpha Mapping Project (LAMP) far-UV spectrograph on the Lunar Reconnaissance Orbiter (LRO), and the Lunar Dust Experiment (LDEX) on the Lunar Atmosphere and Dust Environment Explorer (LADEE). These searches have only produced upper limits for these exospheric dust abundances, as opposed to a clear detection. This motivated a search for LHG with the LRO star tracker cameras. Despite being designed for spacecraft navigation, the images these cameras produce are very suitable for scientific use. They also offer benefits over instruments previously used in terms of spatial resolution and ability to probe to low altitudes (both are of order a few hundred meters at the limb), as well as sensitivity to a similar wavelength range as the Apollo-era observations. Interestingly, the initial series of searches have resulted in some images that show bright patches at the limb that could be possible evidence for LHG. However, since these patches appear to typically extend only ~1000 m horizontally and just a few hundred meters vertically, this raises the possibility that they are simply due to sunlight reflected off surface topography along the limb. Initial simulations using a 64 pixel/degree digital elevation

  7. Discharge patterns in the lateral superior olive of decerebrate cats.

    Science.gov (United States)

    Greene, Nathaniel T; Davis, Kevin A

    2012-10-01

    Anatomical and pharmacological studies have shown that the lateral superior olive (LSO) receives inputs from a number of sources and that LSO cells can alter the balance of their own excitatory and inhibitory drive. It is thus likely that the ongoing sound-evoked responses of LSO cells reflect a complex interplay of excitatory and inhibitory events, which may be affected by anesthesia. The goal of this study was to characterize the temporal discharge patterns of single units in the LSO of unanesthetized, decerebrate cats in response to long-duration ipsilateral best-frequency tone bursts. A decision tree is presented to partition LSO units on the basis of poststimulus time histogram shape, adaptation of instantaneous firing rate as a function of time, and sustained discharge rate. The results suggest that LSO discharge patterns form a continuum with four archetypes: sustained choppers that show two or more peaks of activity at stimulus onset and little adaptation of rate throughout the response, transient choppers that undergo a decrease in rate that eventually stabilizes with time, primary-like units that display an initial peak of activity followed by a monotonic decline in rate to a steady-state value, and onset-sustained units that exhibit an initial peak of activity at stimulus onset followed by a low sustained activity. Compared with the chopper units, the nonchopper units tend to show longer first-spike latencies, lower peak firing rates, and more irregular sustained discharge patterns. Modeling studies show that the full range of LSO response types can be obtained from an underlying sustained chopper by varying the strength and latency of a sound-driven ipsilateral inhibition relative to that of excitation. Together, these results suggest that inhibition plays a major role in shaping the temporal discharge patterns of units in unanesthetized preparations.

  8. Self-sustaining fuel purging fuel injection system

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, J.R.; Koblish, T.R.

    1994-01-11

    A fuel injector system for a combustor of a gas turbine engine includes first and second fuel injectors rendered operative to discharge fuel to the combustor during a high power regime of engine operation and rendered non-operative during a lower power regime of engine operation. The first and second fuel injectors include respective first and second fuel discharge passages in fuel flow communication to one another and to the combustor via associated fuel discharge lips to sustain a flame region. The first and second fuel injectors are operatively associated with respective first and second air discharge means having air discharge lips for discharging air to the combustor for sustaining the flame region therein. When the fuel injectors are rendered non-operative, different pneumatic pressures are established at the fuel discharge lips to purge fuel from the fuel injectors to the combustor. 26 figs.

  9. Sustainable Transportation

    DEFF Research Database (Denmark)

    Hall, Ralph P.; Gudmundsson, Henrik; Marsden, Greg

    2014-01-01

    that relate to the construction and maintenance of transportation infrastructure and the operation or use of the different transportation modes. The concept of sustainable transportation emerged in response to these concerns as part of the broader notion of sustainable development. Given the transportation...

  10. Sustaining dairy

    NARCIS (Netherlands)

    Villarreal Herrera, Georgina

    2017-01-01

    Dairy in Europe has undergone many changes in the last few years—the abolition of milk production quotas being a fundamental one. This study explores these changes in relation to the sustained social and environmental viability of the sector and how dairy processors' sustainability

  11. Sustainable Universities

    DEFF Research Database (Denmark)

    Grindsted, Thomas Skou

    2011-01-01

    . Declarations tend to have impact on three trends. Firstly, there is emerging international consensus on the university’s role and function in relation to sustainable development; secondly, the emergence of national legislation, and thirdly, an emerging international competition to be leader in sustainable...... campus performance....

  12. Sustainable Transition

    DEFF Research Database (Denmark)

    Hansen, Ole Erik; Søndergård, Bent

    2014-01-01

    of agendas/vision, technologies, actors and institutions in the emergent design of an urban mobility system based on an electric car sharing system. Why. Designing for sustainability is a fundamental challenge for future design practices; designers have to obtain an ability to contribute to sustainable...

  13. Sustainable Learning

    Science.gov (United States)

    Cadwell, Louise; Dillon, Robert

    2011-01-01

    Green schools have moved into a new era that focuses on building a culture of sustainability in every aspect of learning in schools. In the early stages of sustainability education, the focus was on recycling and turning off the lights. Now, students and adults together are moving into the areas of advocacy and action that are based on a deep…

  14. GASEOUS DISCHARGE DEVICE

    Science.gov (United States)

    Gow, J.D.

    1961-01-10

    An extremely compact two-terminal gaseous discharge device is described that is capable of producing neutrons in copious quantities, relatively high energy ions, intense x rays, and the like. Principal novelty resides in the provision of a crossed electric-magnetic field region in the discharge envelope that traps electrons and accelerates them to very high energies to provide an intense ionizing medium adjacent the anode of the device for ionizing gas therein with extremely high efficiency. In addition, the crossed-field trapping region holds the electrons close to the anode whereby the acceleration of ions to the cathode is not materially effected by the electron sheath and the ions assume substantially the full energy of the anodecathode potential drop. (auth)

  15. Epileptiform discharge propagation

    DEFF Research Database (Denmark)

    Mălîia, Mihai Dragos; Meritam, Pirgit; Scherg, Michael

    2016-01-01

    propagation was analyzed using sequential voltage-maps of the averaged spikes, and principal components analysis. When propagation was detected, sources were modeled both at onset and peak. RESULTS: Propagation occurred in half of the patients. The median time of propagation between onset and peak was 17 ms......OBJECTIVE: To investigate how often discharge propagation occurs within the spikes recorded in patients evaluated for epilepsy surgery, and to assess its impact on the accuracy of source imaging. METHODS: Data were analyzed from 50 consecutive patients who had presurgical workup. Discharge....... In 60% of the cases with propagation (15/25 patients) this remained in the same sub-lobar area where onset occurred. The accuracy of source imaging in cases of propagating spikes was 67% when only analyzing onset or peak. This was lower as compared to cases without propagation (79%). Combining source...

  16. Diffuse Discharge Switch Analysis.

    Science.gov (United States)

    1986-02-01

    discharge current, jO’ is also fixed by ne* For methane-argon, 9:1, the minimum starts at an E/n of 2.5 Td and gives an elec-7 (21) tron drift velocity of...deposition (assuming 10 ) is 280 W/cm , the discharge current density (at E/n = 2.5 Td ) is 8 A/cm ,and the area of the switch is 2.5 m . Since one reason for 3...34 ne e = 6.7x10-2 ne A/cm 2 (6) eb (p/p ) 12For ne 5x10,this gives 167211 (mA/cm 2 (7) 3eb (pipo0 ) The current gain is JO e ve ne 2.4 x 1014 (8) Jeb

  17. 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.

  18. Effects of annealing on glow peak parameters of LiF:Mg,Ti (TLD-100) dosimetry material

    Energy Technology Data Exchange (ETDEWEB)

    Piters, T.M. [Universidad de Sonora (Mexico). Centro de Investigacion en Fisica; Boss, A.J.J.; Burg, B. van der [Delft University of Technology (Netherlands). Interfaculty Reactors Institute

    1996-12-31

    Computerised glow curve analysis has been used to examine the dependence of the peak parameters of LiF:Mg,Ti (TLD-100) on the pre-irradiation annealing procedure in the temperature range 353 K to 673 K. The intensities of the main peaks 1, 2, 3, 4 and 5 as well as the activation energies and frequency factors were found to vary strongly with the pre-irradiation low temperature annealing. The trends in the changes of the glow curves with respect to peaks 2 and 5 could be explained by the defect reaction equation MgV {r_reversible} (MgV){sub 2} {r_reversible} (MgV){sub 3} {r_reversible} precipitates, and an additional assumption that the traps responsible for peak 2 react during read out with MgV and (MgV){sub 2}. The `precipitation` process was found to be frozen in at temperatures lower than 373 K. The influences of variations in the cooling rate in the annealing procedure on the glow curve shape are discussed. It was found that for accurate dosimetry the cooling applied in the annealing procedure is not a very critical factor for high cooling rates (> 1 K.s{sup -1}) but may be a very critical factor for low cooling rates (< 0.08 K.s{sup -1}). (author).

  19. 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.

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

    Science.gov (United States)

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

  2. Effects of oxygen concentration on atmospheric pressure dielectric barrier discharge in Argon-Oxygen Mixture

    Science.gov (United States)

    Li, Xuechun; Li, Dian; Wang, Younian

    2016-09-01

    A dielectric barrier discharge (DBD) can generate a low-temperature plasma easily at atmospheric pressure and has been investigated for applications in trials in cancer therapy, sterilization, air pollution control, etc. It has been confirmed that reactive oxygen species (ROS) play a key role in the processes. In this work, we use a fluid model to simulate the plasma characteristics for DBD in argon-oxygen mixture. The effects of oxygen concentration on the plasma characteristics have been discussed. The evolution mechanism of ROS has been systematically analyzed. It was found that the ground state oxygen atoms and oxygen molecular ions are the dominated oxygen species under the considered oxygen concentrations. With the oxygen concentration increasing, the densities of electrons, argon atomic ions, resonance state argon atoms, metastable state argon atoms and excited state argon atoms all show a trend of decline. The oxygen molecular ions density is high and little influenced by the oxygen concentration. Ground state oxygen atoms density tends to increase before falling. The ozone density increases significantly. Increasing the oxygen concentration, the discharge mode begins to change gradually from the glow discharge mode to Townsend discharge mode. Project supported by the National Natural Science Foundation of China (Grant No. 11175034).

  3. Fluid model for a partially packed dielectric barrier discharge plasma reactor

    Science.gov (United States)

    Gadkari, Siddharth; Tu, Xin; Gu, Sai

    2017-09-01

    In this work, a two-dimensional numerical fluid model is developed for a partially packed dielectric barrier discharge (DBD) in pure helium. Influence of packing on the discharge characteristics is studied by comparing the results of DBD with partial packing with those obtained for DBD with no packing. In the axial partial packing configuration studied in this work, the electric field strength was shown to be enhanced at the top surface of the spherical packing material and at the contact points between the packing and the dielectric layer. For each value of applied potential, DBD with partial packing showed an increase in the number of pulses in the current profile in the positive half cycle of the applied voltage, as compared to DBD with no packing. Addition of partial packing to the plasma-alone DBD also led to an increase in the electron and ion number densities at the moment of breakdown. The time averaged electron energy profiles showed that a much higher range of electron energy can be achieved with the use of partial packing as compared to no packing in a DBD, at the same applied power. The spatially and time averaged values over one voltage cycle also showed an increase in power density and electron energy on inclusion of partial packing in the DBD. For the applied voltage parameters studied in this work, the discharge was found to be consistently homogeneous and showed the characteristics of atmospheric pressure glow discharge.

  4. Experimental analysis on the effects of DC arc discharges at various flow regimes

    Science.gov (United States)

    Bianchi, G.; Saracoglu, B. H.; Paniagua, G.; Regert, T.

    2015-03-01

    This paper addresses the control of the boundary layer on a compression ramp by means of DC electrical arc discharges. The development and realization of the control system are first described and then assessed in the wind tunnel. The objective of the research was to control the supersonic flow using the minimum amount of energy. The array of electrodes was located at the base of a ramp, where a low momentum flow develops. The electrical discharge was generated by a custom designed electronic facility based on high-voltage ignition coils. The slanted tungsten electrodes were insulated by mounting them in a ceramic support. The discharge evolution was studied through high-speed flow visualizations, while electrical measurements at the high-voltage section of the circuitry allowed to estimate the energy release. The development of a high-speed short exposure Schlieren imaging technique, based on a very short duration laser pulse illumination and a double shot CCD camera, allowed to observe the macroscopic effects associated with the arc establishment between the electrodes (glow, sound wave and heat release). Due to the long residence time, the thermal perturbation spread along the streamwise direction. Cross correlation of Schlieren images with short time separation revealed that in supersonic conditions, the discharges led to an overall acceleration of the flow field underneath the oblique shock wave.

  5. 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.

  6. 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

  7. Sustainable consumption

    DEFF Research Database (Denmark)

    Prothero, Andrea; Dobscha, Susan; Freund, Jim

    2011-01-01

    This essay explores sustainable consumption and considers possible roles for marketing and consumer researchers and public policy makers in addressing the many sustainability challenges that pervade our planet. Future research approaches to this interdisciplinary topic need to be comprehensive...... and systematic and will benefit from a variety of different perspectives. There are a number of opportunities for future research, and three areas are explored in detail. First, the essay considers the inconsistency between the attitudes and behaviors of consumers with respect to sustainability; next, the agenda...... is broadened to explore the role of individual citizens in society; and finally, a macro institutional approach to fostering sustainability is explored. Each of these areas is examined in detail and possible research avenues and public policy initiatives are considered within each of these separate...

  8. Stabilizing Sustainability

    DEFF Research Database (Denmark)

    Reitan Andersen, Kirsti

    The publication of the Brundtland Report in 1987 put the topic of sustainable development on the political and corporate agenda. Defining sustainable development as “a development that meets the needs of the future without compromising the ability of future generations to meet their own needs......” (WCED, 1987, p. 43), the Report also put a positive spin on the issue of sustainability by upholding capitalist beliefs in the possibility of infinite growth in a world of finite resources. While growth has delivered benefits, however, it has done so unequally and unsustainably. This thesis focuses...... on the textile and fashion industry, one of the world’s most polluting industries and an industry to some degree notorious for leading the ‘race to the bottom’ in global labour standards. Despite being faced with increasing demands to practise sustainability, most textile and fashion companies continue to fail...

  9. Sustainability reporting

    NARCIS (Netherlands)

    Kolk, A.

    2005-01-01

    This article gives an overview of developments in sustainability (also sometimes labelled corporate social responsibility) reporting. The article will first briefly indicate how accountability on social and environmental issues started, already in the 1970s when social reports were published.

  10. Sustainable Cities

    DEFF Research Database (Denmark)

    Georg, Susse; Garza de Linde, Gabriela Lucía

    Judging from the number of communities and cities striving or claiming to be sustainable and how often eco-development is invoked as the means for urban regeneration, it appears that sustainable and eco-development have become “the leading paradigm within urban development” (Whitehead 2003......), urban design competitions are understudied mechanisms for bringing about field level changes. Drawing on actor network theory, this paper examines how urban design competitions may bring about changes within the professional field through the use of intermediaries such as a sustainable planning....../assessment tool. The context for our study is urban regeneration in one Danish city, which had been suffering from industrial decline and which is currently investing in establishing a “sustainable city”. Based on this case study we explore how the insights and inspiration evoked in working with the tool...

  11. Sustainable responsibilities?

    DEFF Research Database (Denmark)

    Lystbæk, Christian Tang

    2015-01-01

    This working paper analyzes the conceptions of corporate responsibility for sustainable development in EU policies on CSR. The notion of corporate responsibility has until recently been limited to economical and legal responsibilities. Based on this narrow conception of corporate responsibility.......e. a combination of destruction and construction, this chapter will deconstruct conceptions of responsibility for sustainable development in these EU documents on CSR. A deconstructive conceptual analysis involves destructing dominant interpretations of a text and allowing for constructions of alternative...... such as sustainability actually means, but on what the concept says and does not say. A deconstructive analysis of EU policies on CSR, then, pinpoints that such policies are sites of conceptual struggles. This kind of analysis is suitable for studying conceptions of corporate responsibility for sustainable development...

  12. Agriculture: Sustainability

    Science.gov (United States)

    Sustainability creates and maintains the conditions under which humans and nature can exist in productive harmony, that permit fulfilling the food, feed, and fiber needs of our country and the social, economic and other requirements.

  13. Arc Discharge Electrode Phenomena

    Science.gov (United States)

    Ecker, G.

    The ASI was dedicated to the topic "Electrical Breakdown and Discharges in Gases," — a part of the general field called "Gaseous Electronics." There are physicists — more than a few — who have hardly heard about Gaseous Electronics. There are others — particularly, so called pure theoreticians — who consider this field the esoterica of physics filled with bizarre oddities. But there are also those experts who dared to look closer into this field and found that it has many fascinating and tempting aspects combining extreme features from various fields of physics.

  14. 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.

  15. Sustainable finance

    OpenAIRE

    Boersma-de Jong, Margreet F.

    2012-01-01

    Presentation for Springschool of Strategy, University of Groningen, 10 October 2012. The role of CSR is to stimulate ethical behaviour, and as a result, mutual trust in society. Advantage of CSR for the company and the evolution of CSR. From CSR to Sustainable Finance: how does CSR influence Sustainable Business Administration & Management Accounting, Financial Leadership and what is the importance of CSR in the financial sector

  16. A new mode to excite a gas-discharge XeCL laser

    NARCIS (Netherlands)

    Timmermans, J.C.M.; van Goor, F.A.; Witteman, W.J.

    1993-01-01

    The charge mode is a new mode to excite a discharge XeCl laser based on the dynamics of a spiker-sustainer circuit with a magnetic pulse compressor. The breakdown voltage is higher than in any other mode, due to a very fast rise time. The higher breakdown voltage provides a wider discharge and we

  17. A 5 cm single-discharge CO2 laser having high power output

    NARCIS (Netherlands)

    Ernst, G.J.; Boer, A.G.

    1980-01-01

    A single-discharge self-sustained CO2 laser has been constructed with a gap distance of 5 cm. The system has a very simple construction; it produces a very uniform discharge with an output power of 50 Joules per liter for a CO2 : N2 : He = 1 : 1 : 3 mixture. The efficiency can be as high as 19%.

  18. SUSTAINABLE TRANSPORTATION

    Directory of Open Access Journals (Sweden)

    Linda STEG

    2007-01-01

    Full Text Available This paper discusses possible contributions of psychologists to sustainable transportation. It is argued that in order to reach sustainable transportation, among others, behaviour changes of individual car users are needed. As transport policies will be more effective if they target important antecedents of travel behaviour, first, factors influencing such behaviour are discussed. It is argued that car use is very attractive and sometimes even necessary for many different reasons. This implies that a combination of policies is called for, each targeting different factors that support car use and hinder the use of more sustainable modes of transport. Next, the paper elaborates on policy strategies that may be employed to achieve sustainable transportation by changing car use. Increasing the attractiveness of sustainable transport modes by means of pull measures seems not sufficient to reduce the level of car use. Besides, car use should be made less attractive by means of push measures to force drivers to reconsider their travel behaviour. The acceptability of such policies may be increased by clearly communicating the aim of these policies, and the expected positive consequences (e.g., less congestion, improved environmental quality. Moreover, possible negative effects for individual freedom may be compensated by implementing additional policies aimed at facilitating the use of sustainable transport modes.

  19. Sustainable markets for sustainable energy

    Energy Technology Data Exchange (ETDEWEB)

    Millan, J.; Smyser, C.

    1997-12-01

    The author discusses how the Inter-American Development Bank (IDB) is involved in sustainable energy development. It presently has 50 loans and grants for non conventional renewable energy projects and ten grants for efficiency programs for $600 and $17 million respectively, representing 100 MW of power. The IDB is concerned with how to create a sustainable market for sustainable energy projects. The IDB is trying to work with government, private sector, NGOs, trading allies, credit sources, and regulators to find proper roles for such projects. He discusses how the IDB is working to expand its vision and objectives in renewable energy projects in Central and South America.

  20. Dynamics of the atmospheric pressure diffuse dielectric barrier discharge between cylindrical electrodes in roll-to-roll PECVD reactor

    Science.gov (United States)

    Starostin, Sergey A.; Welzel, Stefan; Liu, Yaoge; van der Velden-Schuermans, Bernadette; Bouwstra, Jan B.; van de Sanden, Mauritius C. M.; de Vries, Hindrik W.

    2015-07-01

    The high current diffuse dielectric barrier discharge (DBD) was operated in a bi-axial cylindrical electrode configuration using nitrogen, oxygen and argon gas flow with the addition of tetraethyl orthosilicate as precursor for silica-like film deposition. The behaviour of the transient plasma was visualized by means of fast imaging from two orthogonal directions. The formation and propagation (~3 × 104 m s-1) of lateral ionization waves with the transverse light emission structure similar to the low pressure glow discharge was observed at time scales below 1 µs. Despite plasma non-uniformity at nanosecond time scale the deposition process on the web-rolled polymer results in smooth well adherent films with good film uniformity and excellent gas diffusion barrier properties. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  1. Evolution of a Diffusion Channel in an Inhomogeneous Electric Field of the KrF-Laser Pump Discharge

    Science.gov (United States)

    Yampol'skaya, S. A.; Yastremsky, A. G.; Panchenko, Yu. N.; Puchikin, A. V.; Bobrovnikov, S. M.

    2018-01-01

    The results of studying the 2D-simulation of evolution of a diffusion channel in the KrF-laser pump discharge initiated by the pin on the cathode surface are presented. It is shown that during the pump pulse, the inhomogeneity passes successively through three stages: a plasma spot on the cathode surface, a diffuse channel, and a high-conductivity channel. From the analysis of the dynamics of spatial distribution of spontaneous emission on the B0-X transition of the KrF molecule in such a discharge, it is obtained that the channel can work as an amplifying medium while the volumetric form of its glow is maintained. Despite the contraction of the channel into a narrow cord at the end of the pump pulse, the distribution of the radiation energy over the entire pulse has the shape of a torch with the width at the anode of 0.6 cm.

  2. Discharge consents in Scotland.

    Science.gov (United States)

    Rosie, Andrew J; Singleton, Peter T R

    2002-06-01

    The Scottish Environment Protection Agency (SEPA) is charged with the protection of the Scottish environment, and this is achieved through the regulation of polluting discharges and through consulting, influencing and educating others who interact with it. This paper describes aspects of the agency's regulatory work as it applies to the Scottish fish-farming industry. By far the largest sector of the industry in Scotland involves the rearing of fin-fish in cages, presently still dominated by Atlantic salmon, and the paper is based on experiences gained within this sector. The present circumstances affecting its development are described with reference to the environmental impacts associated with cage-rearing techniques used for production in marine waters. This paper briefly reviews the statutory background behind Scotland's system of discharge consents, including relevant aspects of European legislation. Methods developed to control the environmental risks posed by sea louse treatment chemicals are described. The concept of farming the sea is explored in relation to SEPA's 'allowable zone of effects' approach and the growing public concern about perceived environmental damage. Finally, the future prospects for the industry in Scotland are reviewed in relation to sea louse control.

  3. Application Of Lean Strategy To Redesign The Assembly Process Flow Of Glow Plug

    Directory of Open Access Journals (Sweden)

    Rahul Vylen

    2013-06-01

    Full Text Available Lean manufacturing is an applied methodology of scientific objective techniques which will improve the tasks in a process to be performed with a minimum of non-value-added activities. It is being increasingly adopted as a potential solution for many automotive manufacturing industries. This paper addresses the implementation of lean principles in an automotive component manufacturing company with a focus on current manufacturing practices and visual identification of non-value-added time, such as bottle necking, waiting time and material handling, etc. The typical operations involved in making the Glow Plug are caulking, tig welding, MgO filling & O-ring pressing, swaging, facing, thread rolling, inspection and assembly. The facing operation can be eliminated by stabilizing the variations generated during the MgO filling machine. The MgO filling activity contains various forms of non-value-added activities such as worn-out gripper, insufficient clamping tension, physical shaking of the WPC on the agitation unit instead of fine vibration, Jerky insertion of the WPC shank into the agitation locator. It was identified that approximately 15mm material was wasted per piece, though there is no value addition on the part. This project utilizes Lean tools such as “Six Sigma” and “Value Stream Mapping” procedures. Resolving and improving the above problems resulted in drastic increase in productivity by 87% from 82%, reduction in the rejections by 13% from 18%, reduction in the manufacturing lead time by 2.62 days/annum, reduction in the utilization of shop floor space by 6m2 and also the manufacturing cost by 1.16 million INR/ annum.

  4. Diagnostic Study and Self-Consistent Modelling of a Low-Pressure He-Xe Discharge for Lighting Purpose

    Science.gov (United States)

    Bussiahn, René; Gortchakov, Serguei; Lange, Hartmut; Uhrlandt, Dirk

    2003-10-01

    A glow discharge in a mixture of helium and 2% xenon in a cylindrical tube is considered, which can be used for the design of mercury-free low-pressure VUV radiation sources and fluorescent lamps. Optimal operation conditions with respect to the efficiency and the output power of the 147 nm resonance radiation of xenon atoms are evaluated by experimental investigations assisted by a self-consistent analysis of the dc positive column plasma. The column plasma is investigated in the range of the total pressure p0 from 133 to 470 Pa at discharge currents Iz from 5 to 200 mA using tubes with the radii r_w=0.5, 0.875 and 1.12 cm. Tunable diode laser absorption spectroscopy has been applied to determine the absolute densities of the Xe(1s_5), Xe(1s_4), Xe(1s_3) and Xe(1s_2) states and their radial profiles. The axial electric field has been measured by means of two Langmuir probes. Theoretical investigations of the dc column plasma use a self-consistent hybrid model which comprises a treatment of the non-local electron kinetics and the radial space charge confinement as well as a detailed balance description of all important excited states. The accuracy of the model is evaluated by detailed comparisons of model results and measurements for several discharge parameter conditions. In addition, the model is used for the study of the radiation efficiency and output power in extended parameter ranges of the dc glow discharge.

  5. The End of Days -- Chandra Catches X-ray Glow From Supernova

    Science.gov (United States)

    1999-12-01

    Through a combination of serendipity and skill, scientists have used NASA's Chandra X-ray Observatory to capture a rare glimpse of X-radiation from the early phases of a supernova, one of the most violent events in nature. Although more than a thousand supernovas have been observed by optical astronomers, the early X-ray glow from the explosions has been detected in less than a dozen cases. The Chandra observations were made under the direction of a team of scientists from the Massachusetts Institute of Technology (MIT) in Cambridge, led by Walter Lewin and his graduate student, Derek Fox. When combined with simultaneous observations by radio and optical telescopes, the X-ray observations tell about the thickness of the shell that was blown off, its density, its speed, and how much material was shed by the star before it exploded. Chandra observed an X-ray glow from SN1999em with the total power of 50,000 suns. Ten days later it observed the supernova for another nine hours, and found that the X rays had faded to half their previous intensity. The optical luminosity, which had the brightness of 200 million suns, had faded somewhat less. No radio emission was detected at any time. With this information, the MIT group and their colleagues are already piecing together a picture of the catastrophic explosion. Observations by optical astronomers showed that SN1999em was a Type II supernova produced by the collapse of the core of a star ten or more times as massive as the Sun. The intense heat generated in the collapse produces a cataclysmic rebound that sends high speed debris flying outward at speeds in excess of 20 million miles per hour. The debris crashes into matter shed by the former star before the explosion. This awesome collision generates shock waves that heat expanding debris to three million degrees. The X-ray glow from this hot gas was detected by Chandra and gives astrophysicists a better understanding of the dynamics of the explosion, as well as the

  6. One-dimensional electromagnetic band gap structures formed by discharge plasmas in a waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Arkhipenko, V. I.; Simonchik, L. V., E-mail: l.simonchik@dragon.bas-net.by; Usachonak, M. S. [B.I. Stepanov Institute of Physics of the NAS of Belarus, Ave. Nezavisimostsi 68, 220072 Minsk (Belarus); Callegari, Th.; Sokoloff, J. [Université de Toulouse, UPS, INPT, LAPLACE, Laboratoire Plasma et Conversion d' Energie, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France)

    2014-09-28

    We demonstrate the ability to develop one-dimensional electromagnetic band gap structure in X-band waveguide solely by using the positive columns of glow discharges in neon at the middle pressure. Plasma inhomogeneities are distributed uniformly along a typical X-band waveguide with cross section of 23×10 mm². It is shown that electron densities larger than 10¹⁴ cm ⁻³ are needed in order to create an effective one-dimensional electromagnetic band gap structure. Some applications for using the one-dimensional electromagnetic band gap structure in waveguide as a control of microwave (broadband filter and device for variation of pulse duration) are demonstrated.

  7. LM-OSL thermal activation curves of quartz: Relevance to the thermal activation of the 110 deg. C TL glow-peak

    Energy Technology Data Exchange (ETDEWEB)

    Kiyak, N.G. [Physics Department, Faculty of Science and Arts, ISIK University, Istanbul (Turkey)], E-mail: kiyak@isikun.edu.tr; Polymeris, G.S. [Archaeometry Laboratory, Cultural and Educational Technology Institute, R.C. ' Athena' , Tsimiski 58, 67100 Xanthi (Greece); Nuclear Physics Laboratory, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Kitis, G. [Nuclear Physics Laboratory, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

    2008-02-15

    The thermally activated characteristics (TAC) of the linearly modulated optically stimulated luminescence (LM-OSL) signals of seven quartz samples from different origin were studied relative to the TAC of their respective thermoluminescence (TL) glow-peaks at 110 deg. C. Within the framework of the study the TAC behavior of the LM-OSL was investigated by measuring the OSL signal at room temperature (RT) with the 110 deg. C glow-peak present during OSL measurements, as well as, at 125 deg. C without the glow-peak at 110 deg. C removed by a cut-heat at 180 deg. C prior to OSL measurement. The LM-OSL curves were analyzed into individual components using a computerized deconvolution procedure. It was found that all individual LM-OSL components of each kind of quartz follow the TAC behavior of the respective TL glow-peak at 110 deg. C. The fourth component of the LM-OSL curve, centered at about t{sub m}=400s, appeared when the OSL measurements were performed at RT, whereas it was absent when the OSL measurement were performed at 180 deg. C. It is suggested that this component is closely related with the TL glow-peak at 110 deg. C.

  8. Roundtabling Sustainability

    DEFF Research Database (Denmark)

    Ponte, Stefano

    2014-01-01

    The willingness of public authority to delegate social and environmental regulation to the private sector has varied from sector to sector, but has often led to the establishment of ‘voluntary’ standards and certifications on sustainability. Many of these have taken the form of ‘stewardship...... councils’ and ‘sustainability roundtables’ and have been designed around a set of institutional features seeking to establish legitimacy, fend off possible criticism, and ‘sell’ certifications to potential users. The concept of ‘roundtabling’ emphasizes the fitting a variety of commodity......-specific sustainability situations into a form that not only ‘hears more voices’ (as in ‘multi-stakeholder’), but also portrays to give them equal standing at the table of negotiations (roundtable), thus raising higher expectations on accountability, transparency and inclusiveness. In this article, I examine to what...

  9. Sustainability Evaluation.

    Science.gov (United States)

    Stichnothe, Heinz

    2017-03-17

    The long-term substitution of fossil resources can only be achieved through a bio-based economy, with biorefineries and bio-based products playing a major role. However, it is important to assess the implications of the transition to a bio-based economy. Life cycle-based sustainability assessment is probably the most suitable approach to quantify impacts and to identify trade-offs at multiple levels. The extended utilisation of biomass can cause land use change and affect food security of the most vulnerable people throughout the world. Although this is mainly a political issue and governments should be responsible, the responsibility is shifted to companies producing biofuels and other bio-based products. Organic wastes and lignocellulosic biomass are considered to be the preferred feedstock for the production of bio-based products. However, it is unlikely that a bio-based economy can rely only on organic wastes and lignocellulosic biomass.It is crucial to identify potential problems related to socio-economic and environmental issues. Currently there are many approaches to the sustainability of bio-based products, both quantitative and qualitative. However, results of different calculation methods are not necessarily comparable and can cause confusion among decision-makers, stakeholders and the public.Hence, a harmonised, globally agreed approach would be the best solution to secure sustainable biomass/biofuels/bio-based chemicals production and trade, and to avoid indirect effects (e.g. indirect land use change). However, there is still a long way to go.Generally, the selection of suitable indicators that serve the purpose of sustainability assessment is very context-specific. Therefore, it is recommended to use a flexible and modular approach that can be adapted to various purposes. A conceptual model for the selection of sustainability indicators is provided that facilitates identifying suitable sustainability indicators based on relevance and significance in a

  10. Determination of gamma dose and thermal neutron fluence in BNCT beams from the TLD-700 glow curve shape

    Energy Technology Data Exchange (ETDEWEB)

    Gambarini, G., E-mail: grazia.gambarini@mi.infn.i [Universita degli Studi di Milano, Dipartimento di Fisica, via Celoria 16, 20133 Milano (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Bartesaghi, G. [Universita degli Studi di Milano, Dipartimento di Fisica, via Celoria 16, 20133 Milano (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Agosteo, S.; Vanossi, E. [Politecnico di Milano, Dipartimento di Energia, via Ponzio 34/3, 20133 Milano (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Carrara, M.; Borroni, M. [Fondazione IRCCS, Istituto Nazionale dei Tumori, Medical Physics Unit, via Venezian 1, 20133 Milano (Italy)

    2010-03-15

    The measurement of both gamma dose and thermal neutron fluence in a BNCT gamma-neutron mixed-field can be achieved by means of a single thermoluminescence dosimeter (TLD-700), exploiting the shape of the glow-curve (GC). The method is based on simple algorithms containing parameters obtained from the TLD-700 GC and requires the gamma calibration GC (for gamma dose measurement) or the thermal neutron calibration GC (for neutron fluence measurement) and moreover the GC of a TLD-600 exposed to a BNCT field, uncalibrated. Some results are reported, showing the potentiality of the method.

  11. Pseudoinefficacy: Negative feelings from children who cannot be helped reduce warm glow for children who can be helped

    Directory of Open Access Journals (Sweden)

    Daniel eVästfjäll

    2015-05-01

    Full Text Available In a great many situations where we are asked to aid persons whose lives are endangered, we are not able to help everyone. What are the emotional and motivational consequences of not helping all? In a series of experiments, we demonstrate that negative affect arising from children that could not be helped decreases the warm glow of positive feeling associated with aiding the children who can be helped. This demotivation from the children outside of our reach may be a form of pseudoinefficacy that is nonrational. We should not be deterred from helping whomever we can because there are others we are not able to help.

  12. Sustainable Soesterkwartier

    NARCIS (Netherlands)

    Abrahams, H.; Goosen, H.; Jong, de F.; Sickmann, J.; Prins, D.

    2010-01-01

    The municipality of Amersfoort wants to construct an endurable and sustainable eco-town in the Soesterkwartier neighbourhood, by taking future climate change into account. The impact of climate change at the location of the proposed eco-town was studied by a literature review.

  13. Sustainable agriculture

    International Development Research Centre (IDRC) Digital Library (Canada)

    New farming techniques, better food security. Since 1970, IDRC-supported research has introduced sustainable agricultural practices to farmers and communities across the devel- oping world. The result: higher productivity, less poverty, greater food security, and a healthier environment. Opportunities grow on trees in ...

  14. Sustainable Development

    African Journals Online (AJOL)

    Tsegai Berhane Ghebretekle

    Abstract. This article examines the concept of sustainable development after the Post-. 2015 Paris Climate Change Agreement with particular emphasis on Ethiopia. Various African countries are vulnerable to climate change, as is evidenced by recent droughts. Ethiopia is selected as a case study in light of its pace in.

  15. Sustainable machining

    CERN Document Server

    2017-01-01

    This book provides an overview on current sustainable machining. Its chapters cover the concept in economic, social and environmental dimensions. It provides the reader with proper ways to handle several pollutants produced during the machining process. The book is useful on both undergraduate and postgraduate levels and it is of interest to all those working with manufacturing and machining technology.

  16. Architecture Sustainability

    NARCIS (Netherlands)

    Avgeriou, Paris; Stal, Michael; Hilliard, Rich

    2013-01-01

    Software architecture is the foundation of software system development, encompassing a system's architects' and stakeholders' strategic decisions. A special issue of IEEE Software is intended to raise awareness of architecture sustainability issues and increase interest and work in the area. The

  17. Sustainability reporting

    NARCIS (Netherlands)

    Kolk, A.

    2005-01-01

    This article gives an overview of developments in sustainability (also sometimes labelled corporate social responsibility) reporting. It The article will first briefly indicate how accountability on social and environmental issues started, already in the 1970s when social reports were published.

  18. Exergy sustainability.

    Energy Technology Data Exchange (ETDEWEB)

    Robinett, Rush D. III (.; ); Wilson, David Gerald; Reed, Alfred W.

    2006-05-01

    Exergy is the elixir of life. Exergy is that portion of energy available to do work. Elixir is defined as a substance held capable of prolonging life indefinitely, which implies sustainability of life. In terms of mathematics and engineering, exergy sustainability is defined as the continuous compensation of irreversible entropy production in an open system with an impedance and capacity-matched persistent exergy source. Irreversible and nonequilibrium thermodynamic concepts are combined with self-organizing systems theories as well as nonlinear control and stability analyses to explain this definition. In particular, this paper provides a missing link in the analysis of self-organizing systems: a tie between irreversible thermodynamics and Hamiltonian systems. As a result of this work, the concept of ''on the edge of chaos'' is formulated as a set of necessary and sufficient conditions for stability and performance of sustainable systems. This interplay between exergy rate and irreversible entropy production rate can be described as Yin and Yang control: the dialectic synthesis of opposing power flows. In addition, exergy is shown to be a fundamental driver and necessary input for sustainable systems, since exergy input in the form of power is a single point of failure for self-organizing, adaptable systems.

  19. Sustainable processing

    DEFF Research Database (Denmark)

    Kristensen, Niels Heine

    2004-01-01

    Kristensen_NH and_Beck A: Sustainable processing. In Otto Schmid, Alexander Beck and Ursula Kretzschmar (Editors) (2004): Underlying Principles in Organic and "Low-Input Food" Processing - Literature Survey. Research Institute of Organic Agriculture FiBL, CH-5070 Frick, Switzerland. ISBN 3-906081-58-3...

  20. Sustainable finance

    NARCIS (Netherlands)

    dr. Margreet F. Boersma-de Jong

    2012-01-01

    Presentation for Springschool of Strategy, University of Groningen, 10 October 2012. The role of CSR is to stimulate ethical behaviour, and as a result, mutual trust in society. Advantage of CSR for the company and the evolution of CSR. From CSR to Sustainable Finance: how does CSR influence

  1. On the mechanism of the cathode erosion in negative corona discharge

    Science.gov (United States)

    Petrov, Alexey; Amirov, Ravil; Samoylov, Igor

    2009-10-01

    Negative corona discharge was investigated in atmospheric pressure air and SF6 in Trichel pulse and glow mode in point-to-plane electrode configuration. As a cathode pointed carbon, copper and aluminum pins with tip size 0.02-1 mm were used. It is found that negative corona causes the erosion of cathode surface in form of nanometer-size craters and fissures. Observed etching may be explained in terms of microexplosive process. This process is initiated by interaction of the cathode surface with the cathode-directed ionization wave. This wave is registered as a Trichel pulse. Local electric field of the head of wave gives rise to the field emission from the cathode surface which initiates microexplosion due to Joule heating. It is assumed that a single Trichel pulse causes the ejection of an erosion fragment from the cathode surface and current on the cathode surface runs through the cross-section of elementary erosion fragment. The value of Trichel pulse action integral which depends on the cathode current density and pulse duration and serves as a criterion of micro-explosion is 10^9 A^2s/cm^4. Hence the conclusion has been made that erosion of the cathode in Trichel pulse mode of negative corona was caused by microexplosive processes. General erosion picture of the cathode surface depends on the discharge dynamics. Correlation between discharge dynamics, erosion picture and Trichel pulse parameters was found.

  2. Experimental and theoretical investigations of a low-pressure He-Xe discharge for lighting purpose

    Science.gov (United States)

    Bussiahn, R.; Gortchakov, S.; Lange, H.; Uhrlandt, D.

    2004-05-01

    Low-pressure cylindrical dc glow discharges in a mixture of helium and 2% xenon are studied by experiment and self-consistent modeling. They can be used for the design of mercury-free vacuum ultraviolet sources and fluorescent lamps for publicity lighting. Experimental diagnostics of the column plasma includes measurements of the axial electric field strength and of the axis densities of the four lowest excited states of xenon. The electric field is determined from probe measurements. The particle densities are derived from the results of tunable diode laser absorption spectroscopy. Experimental investigations are assisted by a self-consistent analysis of the dc positive column plasma. A comparison between calculated and measured values of the axial electric field strength and the densities of excited xenon atoms is presented and discussed. The validated model is used for optimization of the discharge conditions by variation of the discharge current, gas pressure, and tube radius with respect to the radiation power and efficiency of the 147 nm resonance line of xenon. The discussion includes an analysis of the power budget of the column plasma.

  3. Efficient self-sustained pulsed CO laser

    NARCIS (Netherlands)

    Peters, P.J.M.

    1978-01-01

    In this paper a simple sealed-off TEA CO laser is described with a self-sustained discharge without an external UV preionization source. At 77 K this system yields more than 600 mJ from a lasing volume of about 60 cm3 CO-N2-He mixture (45 J/ℓ atm. with 15.6% efficiency).

  4. [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.

  5. Batteries: Discharging the right product

    Science.gov (United States)

    Lau, Sampson; Archer, Lynden A.

    2016-03-01

    The chemistry of the discharge products of metal-oxygen batteries is related to the battery's efficiency but knowledge of their formation mechanism is incomplete. Now, the initial discharge product in sodium-oxygen batteries is shown to be sodium superoxide, which undergoes dissolution and then transforms to sodium peroxide dihydrate.

  6. SUSTAINABLE CORPORATE AND SUSTAINABLE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    DORU CÎRNU

    2017-06-01

    Full Text Available In recent decades, the image of the international business environment has changed significantly. Studies conducted by UNCTAD shows that corporate phenomenon developments in the world economy is growing. Without claiming to present an exhaustive topic so vast we tried to capture some "facets" of sustainable development from the perspective of multinational corporations, given the expansion of these economic entities and strengthening their power in the global economy. We present more negative aspects of the actions of multinational corporations in terms of sustainable development, it is very important to know both sides of the coin, which will not only help transnational giants including release. Based on issues such as corporate social responsibility, environmental pollution and workers' rights, we sought to counter official statements. The conclusion is that these economic entities are real forces that can not be ignored in today's world and the obvious problem of sustainable development can not be addressed independently of the phenomenon, context we also identified some possible solutions to conflict of corporations and essence of the concept of sustainable development.

  7. Investigation of the ionisation density dependence of the glow curve characteristics of LIF:MG,TI (TLD-100)

    Science.gov (United States)

    Horowitz, Y. S.; Horowitz, A.; Oster, L.; Marino, S.; Datz, H.; Margaliot, M.

    2008-01-01

    The dependence of the shape of the glow curve of LiF:Mg,Ti (TLD-100) on ionisation density was investigated using irradiation with 90Sr/90Y beta rays, 60 and 250 kVp X rays, various heavy-charged particles and 0.2 and 14 MeV neutrons. Special attention is focused on the properties of high-temperature thermoluminescence; specifically, the behaviour of the high-temperature ratio (HTR) of Peaks 7 and 8 as a function of batch and annealing protocol. The correlation of Peaks 7 and 8 with average linear-energy-transfer (LET) is also investigated. The HTR of Peak 7 is found to be independent of LET for values of LET approximately >30 keV µm−1. The behaviour of the HTR of Peak 8 with LET is observed to be erratic, which suggests that applications using the HTR should separate the contributions of Peaks 7 and 8 using computerised glow curve deconvolution. The behaviour of the HTR following neutron irradiation is complex and not fully understood. The shape of composite Peak 5 is observed to be broader following high ionisation alpha particle irradiation, suggesting that the combined use of the HTR and the shape of Peak 5 could lead to improved ionisation density discrimination for particles of high LET. PMID:18667402

  8. Properties Influencing Plasma Discharges in Packed Bed Reactors

    Science.gov (United States)

    Kruszelnicki, Juliusz; Engeling, Kenneth W.; Foster, John E.; Kushner, Mark J.

    2016-09-01

    Atmospheric pressure dielectric barrier discharges (DBDs) sustained in packed bed reactors (PBRs) are being investigated for CO2 removal and conversion of waste gases into higher value compounds. We report on results of a computational investigation of PBR-DBD properties using the plasma hydrodynamics simulator nonPDPSIM with a comparison to experiments. Dielectric beads (rods in 2D) were inserted between two coplanar electrodes, 1 cm apart filled by humid air. A step-pulse of -30 kV was applied to the top electrode. Material properties of the beads (dielectric constant, secondary emission coefficient) and gas properties (photoionization and photo-absorption cross-sections, temperature) were varied. We found that photoionization plays a critical role in the propagation of the discharge through the PBR, as it serves to seed charges in regions of high electric field. Increasing rates of photo-ionization enable increases in the discharge propagation velocity, ionization rates and production of radicals. A transition between DBD-like and arc-like discharges occurs as the radiation mean free path decreases. Increasing the dielectric constant of the beads increased electric fields in the gas, which translated to increased discharge propagation velocity and charge density until ɛ/ɛ0 100. Secondary electron emission coefficient and gas temperature have minimal impacts on the discharge propagation though the latter did affect the production of reactive species. Work supported by US DOE Office of Fusion Energy Science and the National Science Foundation.

  9. Chandra Resolves Cosmic X-ray Glow and Finds Mysterious New Sources

    Science.gov (United States)

    2000-01-01

    While taking a giant leap towards solving one of the greatest mysteries of X-ray astronomy, NASA's Chandra X-ray Observatory also may have revealed the most distant objects ever seen in the universe and discovered two puzzling new types of cosmic objects. Not bad for being on the job only five months. Chandra has resolved most of the X-ray background, a pervasive glow of X-rays throughout the universe, first discovered in the early days of space exploration. Before now, scientists have not been able to discern the background's origin, because no X-ray telescope until Chandra has had both the angular resolution and sensitivity to resolve it. "This is a major discovery," said Dr. Alan Bunner, Director of NASA's Structure andEvolution of the universe science theme. "Since it was first observed thirty-seven years ago, understanding the source of the X-ray background has been aHoly Grail of X-ray astronomy. Now, it is within reach." The results of the observation will be discussed today at the 195th national meeting of the American Astronomical Society in Atlanta, Georgia. An article describing this work has been submitted to the journal Nature by Dr. Richard Mushotzky, of NASA Goddard Space Flight Center, Greenbelt, Md., Drs. Lennox Cowie and Amy Barger at the University of Hawaii, Honolulu, and Dr. Keith Arnaud of the University of Maryland, College Park. "We are all very excited by this finding," said Mushotzky. "The resolution of most of the hard X-ray background during the first few months of the Chandra mission is a tribute to the power of this observatory and bodes extremely well for its scientific future," Scientists have known about the X-ray glow, called the X-ray background, since the dawn of X-ray astronomy in the early 1960s. They have been unable to discern its origin, however, for no X-ray telescope until Chandra has had both the angular resolution and sensitivity to resolve it. The German-led ROSAT mission, now completed, resolved much of the lower

  10. Sustainable Consumption

    DEFF Research Database (Denmark)

    Røpke, Inge

    2015-01-01

    in wider social, economic and technological frameworks is emphasised. In particular, the chapter is inspired by practice theory and transition theory. First, various trends in consumption are outlined to highlight some of the challenges for sustainability transitions. Then, it is discussed how consumption...... patterns are shaped over time and what should be considered in sustainability strategies. While discussions on consumption often take their point of departure in the perspective of the individual and then zoom to the wider context, the present approach is the opposite. The outline starts with the basic...... biophysical, distributional and economic conditions for high consumption in rich countries and then zooms in on the coevolution of provision systems and consumption, and how consumption is shaped by practices and projects in everyday life. Furthermore, the paper discusses whether and how transition...

  11. Sustainable Buildings

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Elle, Morten

    The scientific community agrees that: all countries must drastically and rapidly reduce their CO2 emissions and that energy efficient houses play a decisive role in this. The general attitude at the workshop on Sustainable Buildings was that we face large and serious climate change problems that ...... that need urgent action. The built environment is an obvious area to put effort into because of the large and cost-effective energy saving potential and potential for Renewable Energy-based supply systems for buildings.......The scientific community agrees that: all countries must drastically and rapidly reduce their CO2 emissions and that energy efficient houses play a decisive role in this. The general attitude at the workshop on Sustainable Buildings was that we face large and serious climate change problems...

  12. 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...

  13. SUSTAINABLE CHEMISTRY FOR SUSTAINABLE INDUSTRY

    Directory of Open Access Journals (Sweden)

    G. Rizzuto

    2015-01-01

    Full Text Available Foundry Alfe Chem is an industrial reality working in the field of lubrication and chemical auxiliaries for industrial processes, which falls within the framework of the emerging and increasingly important «green chemistry». The goal of the company is to develop products that are more environmentally friendly by using raw materials from renewable sources; specifically, Foundry Alfe Chem has a program of self-sustainability that contemplates, for the foreseeable future, the direct production of renewable raw materials. The company has developed a new dedicated product line, Olitema, whose purpose is to offer highly technological solutions with complete environmental sustainability. In this context, Foundry Alfe CHEM has created a new product which represents a breakthrough in the class of HFC hydraulic fluids: Ecosafe Plus is a biodegradable fire-resistant hydraulic fluid with high engineering and technological performances, high environmental sustainability and the best security guarantees in workplaces. Its formulation is glycols-free, and it allows for easier disposal of the exhausted fluid, compared to a traditional water/ glycol-based HFC hydraulic fluid. For what concern the technological properties, Ecosafe Plus has been tested by accredited laboratories with tribological trials (4 Ball wear test ASTM D 4172, Ball on disc test ASTM 6425, Brugger test DIN 51347, Vickers test ASTM D 2882, with elastomer compatibility test (ASTM D 471 and biodegradability test (OECD 310 F.

  14. 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

  15. Sustainable Procurement

    DEFF Research Database (Denmark)

    Telles, Pedro; Ølykke, Grith Skovgaard

    2017-01-01

    and within it how sustainable requirements have increased the level of compliance required, particularly regulatory compliance. Compliance was already present in previous EU public procurement frameworks, but its extent on Directive 2014/24/EU leads the authors to consider the current legal framework...... as subject to substantial regulatory compliance obligations external to the process of procurement. In short, procurement has been transformed in a way to enforce regulatory obligations that are not intrinsic to the process of buying. This leads to the conclusion that questions such as the cost and trade...

  16. Sustainable consumption and marketing

    NARCIS (Netherlands)

    Dam, van Y.K.

    2016-01-01

    Sustainable development in global food markets is hindered by the discrepancy between positive consumer attitudes towards sustainable development or sustainability and the lack of corresponding sustainable consumption by a majority of consumers. Apparently for many (light user) consumers the

  17. Spatio-temporal characterization of the multiple current pulse regime of diffuse barrier discharges in helium with nitrogen admixtures

    Science.gov (United States)

    Bogaczyk, Marc; Tschiersch, Robert; Nemschokmichal, Sebastian; Meichsner, Jürgen

    2017-10-01

    This work reports on the spatio-temporal characterization of the multiple current pulse regime of diffuse barrier discharges driven by sine-wave feeding voltage at a frequency of 2~kHz in helium with small nitrogen admixtures. The discharge gap of 3~mm is bounded by glass plates on both plane electrodes. Priority is given to the lateral discharge inhomogeneities, underlying volume- and surface-memory effects, and the breakdown mechanism. Therefore, relevant processes in the discharge volume and on the dielectric surfaces were investigated by ICCD camera imaging and optical emission spectroscopy in combination with electrical measurements and surface charge diagnostics using the electro-optic Pockels effect of a bismuth silicon oxide crystal. The number of current pulses per half-cycle of the sine-wave voltage rises with increasing nitrogen admixture to helium due to the predominant role of the Penning ionization. Here, the transition from the first glow-like breakdown to the last Townsend-like breakdown is favored by residual species from the former breakdowns which enhance the secondary electron emission during the pre-phase of the later breakdowns. Moreover, the surface charge measurements reveal that the consecutive breakdowns occur alternately at central and peripheral regions on the electrode surface. These spatial inhomogeneities are conserved by the surface charge memory effect as pointed out by the recalculated spatio-temporal development of the gap voltage.

  18. 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.

  19. Discharge cell for ozone generator

    Science.gov (United States)

    Nakatsuka, Suguru

    2000-01-01

    A discharge cell for use in an ozone generator is provided which can suppress a time-related reduction in ozone concentration without adding a catalytic gas such as nitrogen gas to oxygen gas as a raw material gas. The discharge cell includes a pair of electrodes disposed in an opposed spaced relation with a discharge space therebetween, and a dielectric layer of a three-layer structure consisting of three ceramic dielectric layers successively stacked on at least one of the electrodes, wherein a first dielectric layer of the dielectric layer contacting the one electrode contains no titanium dioxide, wherein a second dielectric layer of the dielectric layer exposed to the discharge space contains titanium dioxide in a metal element ratio of not lower than 10 wt %.

  20. Conductive Bands Diminish Electrostatic Discharges

    Science.gov (United States)

    Leung, Philip L.; Whittlesey, Albert

    1992-01-01

    Electrostatic discharges on surfaces covered with electrically insulating paints reduced by connecting edges of painted surfaces to electrical grounds with band of conductive material. Prevents charge build up on paint which eventually arcs to conductive surface, damaging structures and equipment.

  1. Surgery for pancreatic cancer -- discharge

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000820.htm Surgery for pancreatic cancer - discharge To use the sharing features on this ... please enable JavaScript. You had surgery to treat pancreatic cancer . Now that you're going home, follow instructions ...

  2. Self-enhanced plasma discharge effect in the deposition of diamond-like carbon films on the inner surface of slender tube

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yi [Department of 702, Beihang University, Beijing (China); Li, Liuhe, E-mail: liliuhe@buaa.edu.cn [Department of 702, Beihang University, Beijing (China); Luo, Sida [Department of 702, Beihang University, Beijing (China); International Research Institute for Multidisciplinary Science, Beihang University, Beijing (China); Lu, Qiuyuan [Dong Feng Commercial Vehicle Technical Center, Dong Feng Commercial Vehicle Co., LTD, Wuhan (China); Gu, Jiabin; Lei, Ning [Department of 702, Beihang University, Beijing (China); Huo, Chunqin [Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education, Shenzhen University, Guangdong (China)

    2017-01-30

    Highlights: • Effect of inner surface materials of tubes on plasma discharge is examined. • Electron mean free path is used to analyze the films deposition. • Secondary electrons emitted from inner surface of tube enhance plasma discharge. - Abstract: Enhanced glow discharge plasma immersion ion implantation and deposition (EGD-PIII&D) have been proved to be highly effective for depositing diamond-like carbon (DLC) films on the inner surface of the slender quartz tube with a deposition rate of 1.3 μm/min. Such a high-efficiency DLC films deposition was explained previously as the short electrons mean free path to cause large collision frequency between electrons and neutral particles. However, in this paper, we found that the inner surface material of the tube itself play a vital role on the films deposition. To disclose the mechanism of this phenomenon, the effect of different inner surface materials on plasma discharge was experimentally and theoretically investigated. Then a self-enhancing plasma discharge is discovered. It is found that secondary electrons emitted from the inner surface material, whatever it is the tube inner surface or deposited DLC films, can dramatically enhance the plasma discharge to improve the DLC films deposition rate.

  3. Discharge planning in nursing homes.

    OpenAIRE

    Murtaugh, C M

    1994-01-01

    OBJECTIVE. The purpose of this study is to identify nursing home residents who vary in their discharge planning needs. DATA SOURCES AND STUDY SETTING. Administrative records from a database maintained by the National Health Corporation were the primary data source. The 3,883 persons studied were admitted in 1982 to one of 48 nursing homes located in Tennessee, other southern states, and Missouri. STUDY DESIGN. Residents were followed until discharge or for one year, whichever occurred first. ...

  4. Measuring health literate discharge practices.

    Science.gov (United States)

    Innis, Jennifer; Barnsley, Jan; Berta, Whitney; Daniel, Imtiaz

    2017-02-13

    Purpose Health literate discharge practices meet patient and family health literacy needs in preparation for care transitions from hospital to home. The purpose of this paper is to measure health literate discharge practices in Ontario hospitals using a new organizational survey questionnaire tool and to perform psychometric testing of this new survey. Design/methodology/approach This survey was administered to hospitals in Ontario, Canada. Exploratory factor analysis and reliability testing were performed. Findings The participation rate of hospitals was 46 percent. Exploratory factor analysis demonstrated that there were five factors. The survey, and each of the five factors, had moderate to high levels of reliability. Research limitations/implications There is a need to expand the focus of further research to examine the experiences of patients and families. Repeating this study with a larger sample would facilitate further survey development. Practical implications Measuring health literate discharge practices with an organizational survey will help hospital managers to understand their performance and will help direct quality improvement efforts to improve patient care at hospital discharge and to decrease hospital readmission. Originality/value There has been little research into how patients are discharged from hospital. This study is the first to use an organizational survey tool to measure health literate discharge practices.

  5. Glow-to-arc transition events in H2-Ar direct current pulsed plasma: automated measurement of current and voltage.

    Science.gov (United States)

    Mendes, Luciano A; Mafra, Márcio; Rodrigues, Jhonatam C

    2012-01-01

    The glow-to-arc transition phenomena (arcing) observed in plasma reactors used in materials processing was studied through the arcs characteristic current and voltage waveforms. In order to capture these arcs signals, a LABVIEW™ based automated instrumentation system (ARCVIEW) was developed, including the integration of an oscilloscope equipped with proper current and voltage probes. The system also allows capturing the process parameters at the arc occurrence moments, which were used to map the arcs events conditions. Experiments in H(2)-Ar DC pulsed plasma returned signals data from 215 arcs events, which were analyzed through software routines. According to the results, an anti-arcing system should react in the time order of few microseconds to prevent most of the damage caused by the undesired arcing phenomena.

  6. TLD-100 glow-curve deconvolution for the evaluation of the thermal stress and radiation damage effects

    CERN Document Server

    Sabini, M G; Cuttone, G; Guasti, A; Mazzocchi, S; Raffaele, L

    2002-01-01

    In this work, the dose response of TLD-100 dosimeters has been studied in a 62 MeV clinical proton beams. The signal versus dose curve has been compared with the one measured in a sup 6 sup 0 Co beam. Different experiments have been performed in order to observe the thermal stress and the radiation damage effects on the detector sensitivity. A LET dependence of the TL response has been observed. In order to get a physical interpretation of these effects, a computerised glow-curve deconvolution has been employed. The results of all the performed experiments and deconvolutions are extensively reported, and the TLD-100 possible fields of application in the clinical proton dosimetry are discussed.

  7. 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.

  8. 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.

  9. Virtual Sustainability

    Directory of Open Access Journals (Sweden)

    William Sims Bainbridge

    2010-09-01

    Full Text Available In four ways, massively multiplayer online role-playing games may serve as tools for advancing sustainability goals, and as laboratories for developing alternatives to current social arrangements that have implications for the natural environment. First, by moving conspicuous consumption and other usually costly status competitions into virtual environments, these virtual worlds might reduce the need for physical resources. Second, they provide training that could prepare individuals to be teleworkers, and develop or demonstrate methods for using information technology to replace much transportation technology, notably in commuting. Third, virtual worlds and online games build international cooperation, even blending national cultures, thereby inching us toward not only the world consciousness needed for international agreements about the environment, but also toward non-spatial government that cuts across archaic nationalisms. Finally, realizing the potential social benefits of this new technology may urge us to reconsider a number of traditional societal institutions.

  10. Sustainability; Sustentabilidade

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-10-15

    This chapter analyses the production chain of ethanol, considering the impacts on the quality of the air, water supplies, soil occupation and biodiversity, and the efforts for the soil preservation. It is pointed out the activities of the production cycle and use of bio ethanol due to great uncertainties as far the environmental impacts is concerning and that will deserve more attention in future evaluations. At same time, the chapter highlights another activities where the present acknowledge is sufficient to assure the control and/or prediction of consequences of the desired intervention on the environment media to accommodate the sugar and ethanol production expansion. The consideration is not conservative but to promote the sustainable development.

  11. Development of a wireless, self-sustaining damage detection sensor system based on chemiluminescence for structural health monitoring

    Science.gov (United States)

    Kuang, K. S. C.

    2014-03-01

    A novel application of chemiluminescence resulting from the chemical reaction in a glow-stick as sensors for structural health monitoring is demonstrated here. By detecting the presence of light emitting from these glow-sticks, it is possible to develop a low-cost sensing device with the potential to provide early warning of damage in a variety of engineering applications such as monitoring of cracks or damage in concrete shear walls, detecting of ground settlement, soil liquefaction, slope instability, liquefaction-related damage of underground structure and others. In addition, this paper demonstrates the ease of incorporating wireless capability to the sensor device and the possibility of making the sensor system self-sustaining by means of a renewable power source for the wireless module. A significant advantage of the system compared to previous work on the use of plastic optical fibre (POF) for damage detection is that here the system does not require an electrically-powered light source. Here, the sensing device, embedded in a cement host, is shown to be capable of detecting damage. A series of specimens with embedded glow-sticks have been investigated and an assessment of their damage detection capability will be reported. The specimens were loaded under flexure and the sensor responses were transmitted via a wireless connection.

  12. Sustainability Science Needs Sustainable Data!

    Science.gov (United States)

    Downs, R. R.; Chen, R. S.

    2013-12-01

    Sustainability science (SS) is an 'emerging field of research dealing with the interactions between natural and social systems, and with how those interactions affect the challenge of sustainability: meeting the needs of present and future generations while substantially reducing poverty and conserving the planet's life support systems' (Kates, 2011; Clark, 2007). Bettencourt & Kaur (2011) identified more than 20,000 scientific papers published on SS topics since the 1980s with more than 35,000 distinct authors. They estimated that the field is currently growing exponentially, with the number of authors doubling approximately every 8 years. These scholars are undoubtedly using and generating a vast quantity and variety of data and information for both SS research and applications. Unfortunately we know little about what data the SS community is actually using, and whether or not the data that SS scholars generate are being preserved for future use. Moreover, since much SS research is conducted by cross-disciplinary, multi-institutional teams, often scattered around the world, there could well be increased risks of data loss, reduced data quality, inadequate documentation, and poor long-term access and usability. Capabilities and processes therefore need to be established today to support continual, reliable, and efficient preservation of and access to SS data in the future, especially so that they can be reused in conjunction with future data and for new studies not conceived in the original data collection activities. Today's long-term data stewardship challenges include establishing sustainable data governance to facilitate continuing management, selecting data to ensure that limited resources are focused on high priority SS data holdings, securing sufficient rights to allow unforeseen uses, and preparing data to enable use by future communities whose specific research and information needs are not yet known. Adopting sustainable models for archival

  13. Discharge-current characteristics in UV-preionized Kr/He, F2/He gas-mixtures and KrF excimer laser gas. Shigaisen yobi denri Kr/He, F2/He kongo kitai hoden oyobi KrF laser reiki hoden no denryu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, N.; Kawakami, H.; Yukimura, K. (Doshisha University, Kyoto (Japan))

    1992-08-15

    In order to study effects of Kr and F2 on discharge characteristics of KrF excimer laser gas, gap phenomena in Kr/He and F2/He gas-mixtures were observed and discharge current (I[sub d]) was measured. In the range where Kr concentration was over 10% in Kr/He gas, in which production of filamentation as well as glow discharge started, discontinuous change in I[sub d] in the second or third half cycle was observed. According to the results of experiments and model analyses, it was considered that the discontinuity of the current showed the transition point to filamentation. When F2 concentration was in the range between 0.1 and 0.3% in F2/He mixture gas, filamentation and arc with glow were observed. Sine-waveform I[sub d] ended in the first half cycle, and began to flow again after cessation or had almost constant current due to arc and others. When F2 was over 0.4%, only are discharge was observed. It was thus found that F2 has a large effect on discharge characteristics of KrF laser gas. 18 refs., 9 figs.

  14. Mechanism of formation of subnanosecond current front in high-voltage pulse open discharge

    Science.gov (United States)

    Schweigert, I. V.; Alexandrov, A. L.; Zakrevsky, Dm. E.; Bokhan, P. A.

    2014-11-01

    The mechanism of subnanosecond current front rise observed previously in the experiment in high-voltage pulse open discharge in helium is studied in kinetic particle-in-cell simulations. The Boltzmann equations for electrons, ions, and fast atoms are solved self-consistently with the Poisson equations for the electrical potential. The partial contributions to the secondary electron emission from the ions, fast atoms, photons, and electrons, bombarding the electrode, are calculated. In simulations, as in the experiment, the discharge glows between two symmetrical cathodes and the anode grid in the midplane at P =6 Torr and the applied voltage of 20 kV. The electron avalanche development is considered for two experimental situations during the last stage of breakdown: (i) with constant voltage and (ii) with decreasing voltage. For case (i), the subnanosecond current front rise is set by photons from the collisional excitation transfer reactions. For the case (ii), the energetic electrons swamp the cathode during voltage drop and provide the secondary electron emission for the subnanosecond current rise, observed in the experiment.

  15. Nitriding molybdenum: Effects of duration and fill gas pressure when using 100-Hz pulse DC discharge technique

    Science.gov (United States)

    Ikhlaq, U.; R., Ahmad; Shafiq, M.; Saleem, S.; S. Shah, M.; Hussain, T.; A. Khan, I.; K., Abbas; S. Abbas, M.

    2014-10-01

    Molybdenum is nitrided by a 100-Hz pulsed DC glow discharge technique for various time durations and fill gas pressures to study the effects on the surface properties of molybdenum. X-ray diffractometry (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM) are used for the structural and morphological analysis of the nitrided layers. Vickers' microhardness tester is utilized to investigate surface microhardness. Phase analysis shows the formation of more molybdenum nitride molecules for longer nitriding durations at fill gas pressures of 2 mbar and 3 mbar (1 bar = 105 Pa). A considerable increase in surface microhardness (approximately by a factor of 2) is observed for longer duration (10 h) and 2-mbar pressure. Longer duration (10 h) and 2-mbar fill gas pressure favors the formation of homogeneous, smooth, hard layers by the incorporation of more nitrogen.

  16. Thermoluminescence glow curve for UV induced ZrO2:Ti phosphor with variable concentration of dopant and various heating rate

    Directory of Open Access Journals (Sweden)

    Neha Tiwari

    2014-10-01

    Full Text Available The present paper reports the synthesis and characterization of Ti doped ZrO2 nanophosphors. The effects of variable concentration of titanium on thermoluminescence (TL behaviour are studied. The samples were prepared by combustion a synthesis technique which is suitable for less time taking techniques also for large scale production for nano phosphors. The starting material used for sample preparation are Zr(NO33 and Ti(NO33 and urea used as a fuel. The prepared sample was characterized by X-ray diffraction technique (XRD with variable concentration of Ti (0.05–0.5 mol% there is no any phase change found with increase the concentration of Ti. Sample shows cubic structure and the particle size calculated by Scherer's formula. The surface morphology of prepared phosphor was determined by field emission gun scanning electron microscopy (FEGSEM technique for optimized concentration of dopant. The good connectivity with grains and the semi-sphere like structure was found by FEGSEM. The functional group analysis was determined by Fourier transform infrared (FTIR spectroscopic techniques. The prepared phosphor examined by thermoluminescence technique. For recording TL glow curve every time 2 mg phosphor was irradiated by UV 254 nm source and fixed the heating rate at 5 °C s−1. Sample shows well resolved peak at 167 °C with a shoulder peak at 376 °C. The higher temperature peak shows the well stability and less fading in prepared phosphor. Also the effect of Ti concentration at fixed UV exposure time was studied. The effect of UV exposure time and dose versus intensity plot was studied. Sample shows linear response with dose and broaden peak with high temperature shows the more stability and less fading in TL glow curve. The linear dose response, high stability and less fading phenomenon shows the sample may be useful for thermoluminescence dosimetry application. Trapping parameters are calculated for every recorded glow curve. The

  17. Enhanced oxygen dissociation in a propagating constricted discharge formed in a self-pulsing atmospheric pressure microplasma jet

    Science.gov (United States)

    Schröder, Daniel; Burhenn, Sebastian; Kirchheim, Dennis; Schulz-von der Gathen, Volker

    2013-11-01

    We report on the propagation of a constricted discharge feature in a repetitively self-pulsing microplasma jet operated in helium with a 0.075 vol% molecular oxygen admixture in ambient air environment. The constricted discharge is about 1 mm in width and repetitively ignites at the point of smallest electrode distance in a wedge-shaped electrode configuration, propagates through the discharge channel towards the nozzle, extinguishes, and re-ignites at the inlet at frequencies in the kHz range. It co-exists with a homogeneous, volume-dominated low temperature (T ⋍ 300 K) α-mode glow. Time-resolved measurements of nitrogen molecule C-state and nitrogen molecule ion B-state emission bands reveal an increase of the rotational temperature within the constricted discharge to about 600 K within 50 µs. Its propagation velocity was determined by phase-resolved diagnostics to be similar to the gas velocity, in the order of 40 m s-1. Two-photon absorption laser-induced fluorescence spectroscopy synchronized to the self-pulsing reveals spatial regions of increased oxygen atom densities co-propagating with the constricted discharge feature. The generated oxygen pulse density is about ten times higher than in the co-existing homogeneous α-mode. Densities reach about 1.5 × 1016 cm-3 at average temperatures of 450 K at the nozzle. This enhanced dissociation of about 80% is attributed to the continuous interaction of the constricted discharge to the co-propagating gas volume.

  18. Chemical routes to discharging graphenides.

    Science.gov (United States)

    Hodge, Stephen A; Buckley, David J; Yau, Hin Chun; Skipper, Neal T; Howard, Christopher A; Shaffer, Milo S P

    2017-03-02

    Chemical and electrochemical reduction methods allow the dispersion, processing, and/or functionalization of discrete sp(2)-hybridised nanocarbons, including fullerenes, nanotubes and graphenes. Electron transfer to the nanocarbon raises the Fermi energy, creating nanocarbon anions and thereby activating an array of possible covalent reactions. The Fermi level may then be partially or fully lowered by intended functionalization reactions, but in general, techniques are required to remove excess charge without inadvertent covalent reactions that potentially degrade the nanocarbon properties of interest. Here, simple and effective chemical discharging routes are demonstrated for graphenide polyelectrolytes and are expected to apply to other systems, particularly nanotubides. The discharging process is inherently linked to the reduction potentials of such chemical discharging agents and the unusual fundamental chemistry of charged nanocarbons.

  19. 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. 

  20. Sustainable Scientists

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Evan

    2008-12-31

    Scientists are front and center in quantifying and solving environmental problems. Yet, as a spate of recent news articles in scientific journals point out, much can be done to enhance sustainability within the scientific enterprise itself, particularly by trimming the energy use associated with research facilities and the equipment therein (i,ii,iii, iv). Sponsors of research unwittingly spend on the order of $10 billion each year on energy in the U.S. alone, and the underlying inefficiencies drain funds from the research enterprise while causing 80 MT CO2-equivalent greenhouse-gas emissions (see Box). These are significant sums considering the opportunity costs in terms of the amount of additional research that could be funded and emissions that could be reduced if the underlying energy was used more efficiently. By following commercially proven best practices in facility design and operation, scientists--and the sponsors of science--can cost-effectively halve these costs, while doing their part to put society on alow-carbon diet.