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Sample records for awa-muatan pijar glow

  1. Electron assisted glow discharges for conditioning fusion tokamak devices

    Science.gov (United States)

    Schaubel, K. M.; Jackson, G. L.

    1989-08-01

    Glow discharge conditioning of tokamaks with graphite plasma-facing surfaces has been used to reduce impurities and obtain density control of the plasma discharge. However, a major operational disadvantage of glow conditioning is the high pressure required to initiate the glow discharge, e.g., approx. 70 mTorr for helium in DIII-D, which requires isolating auxiliary components that can not tolerate the high pressure. An electron-gun assisted glow discharge can lower breakdown pressure, possibly eliminating the necessity of isolating these auxiliary systems during glow discharge conditioning and allowing glow discharge operation at lower pressures.

  2. 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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  4. 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

  5. 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.

  6. Glow discharge based device for solving mazes

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-09-15

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

  7. Electron heating in atmospheric pressure glow discharges

    Science.gov (United States)

    Stark, Robert H.; Schoenbach, Karl H.

    2001-04-01

    The application of nanosecond voltage pulses to weakly ionized atmospheric pressure plasmas allows heating the electrons without considerably increasing the gas temperature, provided that the duration of the pulses is less than the critical time for the development of glow-to-arc transitions. The shift in the electron energy distribution towards higher energies causes a temporary increase in the ionization rate, and consequently a strong rise in electron density. This increase in electron density is reflected in an increased decay time of the plasma after the pulse application. Experiments in atmospheric pressure air glow discharges with gas temperatures of approximately 2000 K have been performed to explore the electron heating effect. Measurements of the temporal development of the voltage across the discharge and the optical emission in the visible after applying a 10 ns high voltage pulse to a weakly ionized steady state plasma demonstrated increasing plasma decay times from tens of nanoseconds to microseconds when the pulsed electric field was raised from 10 to 40 kV/cm. Temporally resolved photographs of the discharge have shown that the plasma column expands during this process. The nonlinear electron heating effect can be used to reduce the power consumption in a repetitively operated air plasma considerably compared to a dc plasma operation. Besides allowing power reduction, pulsed electron heating also has the potential to enhance plasma processes, which require elevated electron energies, such as excimer generation for ultraviolet lamps.

  8. Atmospheric Pressure Glow Discharge with Liquid Electrode

    Science.gov (United States)

    Tochikubo, Fumiyoshi

    2013-09-01

    Nonthermal atmospheric pressure plasmas in contact with liquid are widely studied aiming variety of plasma applications. DC glow discharge with liquid electrode is an easy method to obtain simple and stable plasma-liquid interface. When we focus attention on liquid-phase reaction, the discharge system is considered as electrolysis with plasma electrode. The plasma electrode will supply electrons and positive ions to the liquid surface in a different way from the conventional metal electrode. However, the phenomena at plasma-liquid interface have not been understood well. In this work, we studied physical and chemical effect in liquid induced by dc atmospheric pressure glow discharge with liquid electrode. The experiment was carried out using H-shaped Hoffman electrolysis apparatus filled with electrolyte, to separate the anodic and cathodic reactions. Two nozzle electrodes made of stainless steel are set about 2 mm above the liquid surface. By applying a dc voltage between the nozzle electrodes, dc glow discharges as plasma electrodes are generated in contact with liquid. As electrolyte, we used aqueous solutions of NaCl, Na2SO4, AgNO3 and HAuCl4. AgNO3 and HAuCl4 are to discuss the reduction process of metal ions for synthesis of nanoparticles (NPs). OH radical generation yield in liquid was measured by chemical probe method using terephthalic acid. Discharge-induced liquid flow was visualized by Schlieren method. Electron irradiation to liquid surface (plasma cathode) generated OH- and OH radical in liquid while positive ion irradiation (plasma anode) generated H+ and OH radical. The generation efficiency of OH radical was better with plasma anode. Both Ag NPs in AgNO3 and Au NPs in HAuCl4 were synthesized with plasma cathode while only Au NPs were generated with plasma anode. Possible reaction process is qualitatively discussed. The discharge-induced liquid flow such as convection pattern was strongly influenced by the gas flow on the liquid surface. This work

  9. Probiotic bacteria induce a 'glow of health'.

    Directory of Open Access Journals (Sweden)

    Tatiana Levkovich

    Full Text Available Radiant skin and hair are universally recognized as indications of good health. However, this 'glow of health' display remains poorly understood. We found that feeding of probiotic bacteria to aged mice induced integumentary changes mimicking peak health and reproductive fitness characteristic of much younger animals. Eating probiotic yogurt triggered epithelial follicular anagen-phase shift with sebocytogenesis resulting in thick lustrous fur due to a bacteria-triggered interleukin-10-dependent mechanism. Aged male animals eating probiotics exhibited increased subcuticular folliculogenesis, when compared with matched controls, yielding luxuriant fur only in probiotic-fed subjects. Female animals displayed probiotic-induced hyperacidity coinciding with shinier hair, a feature that also aligns with fertility in human females. Together these data provide insights into mammalian evolution and novel strategies for integumentary health.

  10. A model for explaining some features of shuttle glow

    Science.gov (United States)

    Peters, P. N.

    1985-01-01

    A solid state model is proposed which hopefully removes some of the objections to excited atoms being sources for light emanating from surfaces. Glow features are discussed in terms of excited oxygen atoms impinged on the surface, although other species could be treated similarly. Band formation, excited lifetime shortening and glow color are discussed in terms of this model. The model's inability to explain glow emanating above surfaces indicates a necessity for other mechanisms to satisfy this requirements. Several ways of testing the model are described.

  11. Spectrochemical analysis with DC glow discharges at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Broekaert, J.A.C., E-mail: jose.broekaert@chemie.uni-hamburg.de; Reinsberg, K.-G.

    2015-04-01

    A review on recent work and developments in dc glow discharges at atmospheric pressure when used as radiation sources for optical atomic spectrometry and mass spectrometry is given. Diagnostics and analytical features of dc glow discharges at atmospheric pressure between conductive solid electrodes as well as with a liquid as the cathode and flowing afterglow sources were described. Possibilities for the introduction of analytes in solutions, in the gaseous state and direct solids sampling were discussed. - Highlights: • The state-of-the-art and trends of development of dc glow discharges at atmospheric pressure for spectrochemical analysis are discussed.

  12. Glow phenomenon surrounding the vertical stabilizer and OMS pods

    Science.gov (United States)

    1994-01-01

    This 35mm frame, photographed as the Space Shuttle Columbia was orbiting Earth during a 'night' pass, documents the glow phenomenon surrounding the vertical stabilizer and the Orbital Maneuvering System (OMS) pods of the spacecraft.

  13. 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...

  14. 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.

  15. Advances in the Remote Glow Discharge Experiment

    Science.gov (United States)

    Dominguez, Arturo; Zwicker, A.; Rusaits, L.; McNulty, M.; Sosa, Carl

    2014-10-01

    The Remote Glow Discharge Experiment (RGDX) is a DC discharge plasma with variable pressure, end-plate voltage and externally applied axial magnetic field. While the experiment is located at PPPL, a webcam displays the live video online. The parameters (voltage, magnetic field and pressure) can be controlled remotely in real-time by opening a URL which shows the streaming video, as well as a set of Labview controls. The RGDX is designed as an outreach tool that uses the attractive nature of a plasma in order to reach a wide audience and extend the presence of plasma physics and fusion around the world. In March 2014, the RGDX was made publically available and, as of early July, it has had approximately 3500 unique visits from 107 countries and almost all 50 US states. We present recent upgrades, including the ability to remotely control the distance between the electrodes. These changes give users the capability of measuring Paschen's Law remotely and provides a comprehensive introduction to plasma physics to those that do not have access to the necessary equipment.

  16. 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.

  17. ELECTRON TRANSPORT BEHAVIOURS IN THE NITROGEN DIRECT CURRENT GLOW DISCHARGE

    Institute of Scientific and Technical Information of China (English)

    ZHANG LIAN-ZHU; YU WEI; WANG JIU-LI; HAN LI; FU GUANG-SHENG

    2001-01-01

    A Monte Carlo simulation is presented to describe the electron transport behaviours in the nitrogen direct current glow discharge. The energy and angular distributions of the electrons at different positions of the cathode dark space are calculated; their energy and density distribution features throughout the entire discharge are discussed. The influence of molecular vibrational excitation, typical for electron-molecule collisions, has been studied and the elementary process of active species generation has been illustrated. The simulated results reveal that, in the cathode dark space, the high-energy electrons are mainly forward scattering and behave as a high-energy ‘electron beam'. The sharp increase of the number of secondary electrons plays an important role in producing active species at the interface between the cathode dark space and the negative glow region. The vibrational excitation enhances the energy loss of electrons in the negative glow region.

  18. Comparing investigation of pattern formation in glow and streamer DBD

    Science.gov (United States)

    Li, Ben; Ouyang, Jiting

    2016-11-01

    In this paper, we investigate the behaviors of patterns in dielectric barrier discharge (DBD) in glow and streamer regimes under different operating conditions (driving frequency and voltage) and external electric/magnetic field to explore the similarity and difference of pattern formation. It is found that patterns in both glow and streamer DBDs can be homogenized by decreasing the driving frequency to a low level. But filamentary streamers can still appear at low frequency when the voltage is much higher. With an additional lateral electric field, patterns in both regimes can be homogenized. However, an axial magnetic field makes the glow DBD homogeneous, while the streamer DBD decreases in filamentary size. In both regimes, dynamics and distribution of the space charges, rather than the surface charges, play the predominant role in the formation of DBD patterns. But the surface charges may also play an important role in pattern formation, especially in streamer DBD.

  19. Extension of spatiotemporal chaos in glow discharge-semiconductor systems

    Energy Technology Data Exchange (ETDEWEB)

    Akhmet, Marat, E-mail: marat@metu.edu.tr; Fen, Mehmet Onur [Department of Mathematics, Middle East Technical University, 06800 Ankara (Turkey); Rafatov, Ismail [Department of Physics, Middle East Technical University, 06800 Ankara (Turkey)

    2014-12-15

    Generation of chaos in response systems is discovered numerically through specially designed unidirectional coupling of two glow discharge-semiconductor systems. By utilizing the auxiliary system approach, [H. D. I. Abarbanel, N. F. Rulkov, and M. M. Sushchik, Phys. Rev. E 53, 4528–4535 (1996)] it is verified that the phenomenon is not a chaos synchronization. Simulations demonstrate various aspects of the chaos appearance in both drive and response systems. Chaotic control is through the external circuit equation and governs the electrical potential on the boundary. The expandability of the theory to collectives of glow discharge systems is discussed, and this increases the potential of applications of the results. Moreover, the research completes the previous discussion of the chaos appearance in a glow discharge-semiconductor system [D. D. Šijačić U. Ebert, and I. Rafatov, Phys. Rev. E 70, 056220 (2004).].

  20. Immobilization of proteins on glow discharge treated polymers

    Science.gov (United States)

    Kiaei, D.; Safranj, A.; Chen, J. P.; Johnston, A. B.; Zavala, F.; Deelder, A.; Castelino, J. B.; Markovic, V.; Hoffman, A. S.

    Certain glow discharge-treated surfaces have been shown to enhance retention of adsorbed proteins. On the basis of this phenomenon, we have investigated the possibility of immobilizing (a) albumin for developing thromboresistant and non-fouling surfaces, (b) antibodies for immuno-diagnostic assays and (c) enzymes for various biosensors and industrial bioprocesses. Albumin retention was highest on surfaces treated with tetrafluoroethylene (TFE) compared to untreated surfaces or other glow discharge treatments studied. Preadsorption of albumin on TFE-treated surfaces resulted in low fibrinogen adsorption and platelet adhesion. IgG retention was also highest on TFE-treated surfaces. The lower detection limits of both malaria antigen and circulating anodic antigen of the schistosomiasis worm were enhanced following glow discharge treatment of the assay plates with TFE. Both TFE and tetrachloroethylene (TCE) glow discharge treated surfaces showed high retention of adsorbed horseradish peroxidase (HRP). However, the retained specific activity of HRP after adsorption on TCE-treated surfaces was remarkably higher than on TFE-treated surfaces.

  1. NEW DEVELOPMENT IN DOUBLE GLOW SURFACE ALLOYING TECHNOLOGY

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Several kinds of special alloys are produced on the surfaces of iron and steels by using double glow surface alloying technology. Surface Ni-Cr-Mo-Nb alloy,surface precipitation hardening high speed steel and surface precipitation hardening stainless steel are introduced.

  2. Studying surface glow discharge for application in plasma aerodynamics

    Science.gov (United States)

    Tereshonok, D. V.

    2014-02-01

    Surface glow discharge in nitrogen between two infinite planar electrodes occurring on the same plane has been studied in the framework of a diffusion-drift model. Based on the results of numerical simulations, the plasma structure of this discharge is analyzed and the possibility of using it in plasma aerodynamics is considered.

  3. 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

  4. Glow Discharge Induced Hydroxyl Radical Degradation of 2-Naphthylamine

    Institute of Scientific and Technical Information of China (English)

    Lu Quanfang; Yu Jie; Gao Jinzhang; Yang Wu

    2005-01-01

    In an aqueous solution, normal electrolysis at high voltages switches over sponta-neously to glow discharge electrolysis and gives rise to hydroxyl radical, hydrogen peroxide, andaqueous electron, as well as several other active species. Hydroxyl radical directly attacks or-ganic contaminants to make them oxidized. In the present paper, 2-naphthylamine is eventuallydegraded into hydrogen carbonate and carbon dioxide. The degradation process is analyzed byusing an Ultraviolet (UV) absorption spectrum, high-performance liquid chromatography (HPLC)and chemical oxygen demand (COD). It is demonstrated that 2-naphthylamine (c0 =30 mg.1-1) iscompletely converted within 2h at 30℃ and 600 V by glow discharge electrolysis, and the degra-dation is strongly dependent upon the presence of ferrous ions. COD is ascended in the absenceof ferrous ions and descended in the presence of them.

  5. Self-Consistent Description of Nitrogen dc Glow Discharge

    Institute of Scientific and Technical Information of China (English)

    傅广生; 王久丽; 于威; 韩理

    2002-01-01

    A self-consistent hybrid Monte Carlo fluid model is presented to describe the nitrogen dc glow discharge. The movement of fast electrons is simulated by the Monte Carlo method while the dynamics of slow electrons and ions is by fluid equations. The spatial features of the charged species and the corresponding electric field throughout the discharge have been calculated, which include the creation rates of ions and slow electrons, densities of the charged species, the electric field and the potential distribution. These closely related results can give a selfconsistent explanation of the discharge characteristics throughout the space of nitrogen dc glow discharge. The calculated ion density is also compared with the corresponding experimental result.

  6. 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.

  7. 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.

  8. Inception of Snapover and Gas Induced Glow Discharges

    Science.gov (United States)

    Galofaro, J. T.; Vayner, B. V.; Degroot, W. A.; Ferguson, D. C.; Thomson, C. D.; Dennison, J. R.; Davies, R. E.

    2000-01-01

    Ground based experiments of the snapover phenomenon were conducted in the large vertical simulation chamber at the Glenn Research Center (GRC) Plasma Interaction Facility (PIF). Two Penning sources provided both argon and xenon plasmas for the experiments. The sources were used to simulate a variety of ionospheric densities pertaining to a spacecraft in a Low Earth Orbital (LEO) environment. Secondary electron emission is believed responsible for dielectric surface charging, and all subsequent snapover phenomena observed. Voltage sweeps of conductor potentials versus collected current were recorded in order to examine the specific charging history of each sample. The average time constant for sample charging was estimated between 25 and 50 seconds for all samples. It appears that current drops off by approximately a factor of 3 over the charging time of the sample. All samples charged in the forward and reverse bias directions, demonstrated hysteresis. Current jumps were only observed in the forward or positive swept voltage direction. There is large dispersion in tile critical snapover potential when repeating sweeps on any one sample. The current ratio for the first snapover region jumps between 2 and 4.6 times, with a standard deviation less than 1.6. Two of the samples showed even larger current ratios. It is believed the second large snapover region is due to sample outgassing. Under certain preset conditions, namely at the higher neutral gas background pressures, a perceptible blue-green glow was observed around the conductor. The glow is believed to be a result of secondary electrons undergoing collisions with an expelled tenuous cloud of gas, that is outgassed from the sample. Spectroscopic measurements of the glow discharge were made in an attempt to identify specific lines contributing to the observed glow.

  9. Method of computerized glow curve deconvolution for analysing thermoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, T [Division of General Education, Ashikaga Institute of Technology, Omae-cho 268-1, Ashikaga, Tochigi 326-8558 (Japan); Gartia, R K [Luminescence Dating Laboratory, Manipur University, Imphal 795003 (India)

    2003-11-07

    The conventional worldwide accepted method of computerized glow curve deconvolution based on the general order kinetics formalism has two fatal defects in systems where the trapping levels (two or more) have non-zero retrapping probability. The first one is ignoring the thermal connectivity between thermoluminescence (TL) peaks. This arises from the fact that under such a situation electrons trapped at one trapping level, once activated, can be retrapped in another thermally connected level via the conduction band during the recording of the glow curve. The other is the impossibility of obtaining a global minimum, in fitting the experimental TL with the theoretical one with existing techniques. This paper aims to provide answers to these defects. The first one can be overcome by resorting to rigorous analysis using appropriate mathematical rate equations describing the flow of charge carriers. Though the second defect cannot be overcome completely, one can obtain a reasonable fit, which may not be unique. The algorithm is tested for synthetic as well as experimental glow curves.

  10. Effect of the interaction among traps on the shape of thermoluminescence glow curves

    Energy Technology Data Exchange (ETDEWEB)

    Marcazzo, J. [IFAS, Facultad de Ciencias Exactas, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, 7000 Tandil (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Rivadavia 1917, 1033 Buenos Aires (Argentina); Santiago, M. [IFAS, Facultad de Ciencias Exactas, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, 7000 Tandil (Argentina) and Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Rivadavia 1917, 1033 Buenos Aires (Argentina)]. E-mail: msantiag@exa.unicen.edu.ar; Spano, F. [Autoridad Regulatoria Nuclear, Av. del Libertador 8250, 1429 Buenos Aires (Argentina); Lester, M. [IFAS, Facultad de Ciencias Exactas, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, 7000 Tandil (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Rivadavia 1917, 1033 Buenos Aires (Argentina); Ortega, F. [Facultad de Ingenieria, Universidad Nacional del Centro de la Provincia de Buenos Aires, Av. del Valle 5737, 7400 Olavarria (Argentina); Molina, P. [IFAS, Facultad de Ciencias Exactas, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, 7000 Tandil (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Rivadavia 1917, 1033 Buenos Aires (Argentina); Caselli, E. [IFAS, Facultad de Ciencias Exactas, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, 7000 Tandil (Argentina); Comision de Investigaciones Cientificas de la Provincia de Buenos Aires (CICPBA), calle 526 entre 10 y 11, 1900 La Plata (Argentina)

    2007-09-15

    The effect of the interaction among traps on the structure of thermoluminescence glow curves has been investigated by generating numerically simulated glow curves for a wide range of trap parameters. The results reported in this paper provide useful insights which assist in the analysis of experimental glow curves. The most important result shows that it is incorrect to assume beforehand that each peak is related to a specific trapping state. The validity of the quasiequilibrium approximation is briefly discussed.

  11. A glow curve analyzer (GCA) for routine analysis of personnel thermoluminescent dosemeter results

    Energy Technology Data Exchange (ETDEWEB)

    Chase, W.J. [Health Physics Department, Ontario Power Generation, Whitby, Ont. (Canada)], E-mail: john.chase@opg.com; Bezaire, M.D. [Department of Applied Health Sciences, University of Waterloo, Waterloo, Ont. (Canada); Vanderzwet, F.P. [Bruce Power, P.O. Box 1540, Building B13, Tiverton, Ont., N0G 2T0 (Canada); Taylor, C.E. [Health Physics Department, Ontario Power Generation, Whitby, Ont. (Canada)

    2008-02-15

    A glow curve analyzer (GCA) spreadsheet has been developed using Microsoft Excel to perform glow curve analysis on thermoluminescent dosimeter (TLD) data from a personnel dosimetry system. The TLD data come from cards with four LiF:Mg,Ti chips that have been annealed and therefore have a simple glow peak structure. GCA removes spikes in the glow curve data, and then smoothes it. After select start and end points for the glow peak, it fits a Boltzmann function to represent the glow curve signal background under the glow peak. The Boltzmann function is subtracted and two Weibull curves are fit to the remaining net signal between the start and end points. The first Weibull curve is fit to peak 5, and the second one to any small remaining contribution from peaks 3 and 4 or from contaminants. The sum of the two Weibull curves is the glow curve signal result. GCA provides rapid review and correction of all glow curves, improving the quality of the results and reducing the time required for complete processing of official dose results.

  12. Means of introducing an analyte into liquid sampling atmospheric pressure glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Marcus, R. Kenneth; Quarles, Jr., Charles Derrick; Russo, Richard E.; Koppenaal, David W.; Barinaga, Charles J.; Carado, Anthony J.

    2017-01-03

    A liquid sampling, atmospheric pressure, glow discharge (LS-APGD) device as well as systems that incorporate the device and methods for using the device and systems are described. The LS-APGD includes a hollow capillary for delivering an electrolyte solution to a glow discharge space. The device also includes a counter electrode in the form of a second hollow capillary that can deliver the analyte into the glow discharge space. A voltage across the electrolyte solution and the counter electrode creates the microplasma within the glow discharge space that interacts with the analyte to move it to a higher energy state (vaporization, excitation, and/or ionization of the analyte).

  13. 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...... 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...... for the formation of negative ions in glow discharge time-of-flight mass spectrometry are briefly discussed....

  14. Glow curves and the emission of flux grown BaFCl:Gd crystals

    Energy Technology Data Exchange (ETDEWEB)

    Somaiah, K.; Hari Babu, V. (Osmania Univ., Hyderabad (India). Dept. of Physics)

    1984-03-16

    Thermoluminescence output of the BaFCl is found to be enhanced enormously when it is doped with gadolinium. An incorporation of gadolinium in BaFCl produces additional glow peaks at 455 and 560 K, an optical absorption band at 660 nm, and glow emission bands at 315 and 450 nm. The 315 nm emission band is the characteristic emission of the gadolinium impurity. Since similar emission spectra are obtained for different glow peaks, they are attributed to the luminescent centers caused by the gadolinium impurity in the lattice. The trap depth and frequency factor of additional glow peaks are calculated employing different methods.

  15. Large Scale Modelling of Glow Discharges or Non - Plasmas

    Science.gov (United States)

    Shankar, Sadasivan

    The Electron Velocity Distribution Function (EVDF) in the cathode fall of a DC helium glow discharge was evaluated from a numerical solution of the Boltzmann Transport Equation(BTE). The numerical technique was based on a Petrov-Galerkin technique and a unique combination of streamline upwinding with self -consistent feedback-based shock-capturing. EVDF for the cathode fall was solved at 1 Torr, as a function of position x, axial velocity v_{rm x}, radial velocity v_{rm r}, and time t. The electron-neutral collisions consisted of elastic, excitation, and ionization processes. The algorithm was optimized and vectorized to speed execution by more than a factor of 10 on CRAY-XMP. Efficient storage schemes were used to save the memory allocation required by the algorithm. The analysis of the solution of BTE was done in terms of the 8-moments that were evaluated. Higher moments were found necessary to study the momentum and energy fluxes. The time and length scales were estimated and used as a basis for the characterization of DC glow discharges. Based on an exhaustive study of Knudsen numbers, it was observed that the electrons in the cathode fall were in the transition or Boltzmann regime. The shortest relaxation time was the momentum relaxation and the longest times were the ionization and energy relaxation times. The other times in the processes were that for plasma reaction, diffusion, convection, transit, entropy relaxation, and that for mean free flight between the collisions. Different models were classified based on the moments, time scales, and length scales in their applicability to glow discharges. These consisted of BTE with different number af phase and configuration dimensions, Bhatnagar-Gross-Krook equation, moment equations (e.g. Drift-Diffusion, Drift-Diffusion-Inertia), and spherical harmonic expansions.

  16. Glow Discharge Plasma Nitriding of AISI 304 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    A.QAYYUM; M.A.NAVEED; S.ZEB; G.MURTAZA; M.ZAKAULLAH

    2007-01-01

    Glow discharge plasma nitriding of AISI 304 austenitic stainless steel has been carried out for different processing time under optimum discharge conditions established by spectroscopic analysis.The treated samples were analysed by X-ray diffraction(XRD)to explore the changes induced in the crystallographic structure.The XRD pattern confirmed the formation of an expanded austenite phase(γN)owing to incorporation of nitrogen as an interstitial solid solution in the iron lattice.A Vickers microhardness tester was used to evaluate the surface hardness as a function of indentation depth(μm).The results showed clear evidence of surface changes with substantial increase in surface hardness.

  17. 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.

  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 chemoluminescent 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 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. Assessing the Warm Glow Effect in Contingent Valuations for Public Libraries

    Science.gov (United States)

    Lee, Soon-Jae; Chung, Hye-Kyung; Jung, Eun-Joo

    2010-01-01

    This article aims to present evidence of the warm glow effect in a public library setting. More specifically, it tests whether individual respondents with different values for the warm glow component report different values for their willingness to pay (WTP). The data come from a contingent valuation survey conducted on randomly selected citizens…

  1. A Review on Chemical Effects in Aqueous Solution induced by Plasma with Glow Discharge

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Chemical effects in different aqueous solutions induced by plasma with glow dis charge electrolysis (GDE) and contact glow discharge electrolysis (CGDE) are described in this paper. The experimental and discharge characteristics are also reviewed. These are followed by a discussion of their mechanisms of both anodic and cathodic CGDE..

  2. 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.

  3. Application of computerized glow curve deconvolution to determine the spectroscopy of traps in colorless microcline

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, B. Arunkumar [Department of Radiotherapy, RIMS, Lamphel, Imphal 795004, Manipur (India)], E-mail: arunsb2000@yahoo.co.uk; Singh, A. Nabachandra [Department of Physics, Thoubal College, Thoubal 795138, Manipur (India); Singh, S. Nabadwip [Department of Physics, Kumbi College, Kumbi 795133, Manipur (India); Singh, O. Binoykumar [Department of Physics, Y.K. College, Wangjing 795148, Manipur (India)

    2009-01-15

    Kinetic parameters of glow peaks (as many as 14 in the range of 75-575 deg. C) of colorless microcline have been successfully achieved to a high degree of certainty by resorting to computerized glow curve deconvolution (CGCD) in the framework of kinetics formalism. The second derivative plot of the experimental glow curve is used to locate the hidden glow peaks. The criteria to accept the goodness of fit between the experimental glow curve and the numerically generated best fit curve is judged by statistical test namely, {chi}{sup 2}-test. As a cross check, figure of merit (FOM) is also evaluated. The kinetic parameters of the higher temperature trap electrons of colorless microcline are determined by using lower heating rates.

  4. Research on the Plasma Anemometer Based on AC Glow Discharge

    Directory of Open Access Journals (Sweden)

    Bing Yu

    2017-01-01

    Full Text Available A new plasma anemometer based on AC glow discharge is designed in this article. Firstly, theoretical analysis of plasma anemometer working principle is introduced to prove the feasibility of the experimental measurement method. Then the experiments are carried out to study the effects of different parameters on the static discharge characteristics of the plasma anemometer system, by which the system optimization methods are obtained. Finally, several groups of appropriate parameters are selected to build the plasma anemometer system based on resistance capacitance coupling negative feedback AC glow discharge, and different airflow speeds are applied to obtain the achievable velocity measurement range. The results show that there is a linear relationship between airflow velocity and discharge current in an allowable error range, which can be applied for airflow velocity measurement. Negative feedback coupling module, which is composed of the coupling resistance and the coupling capacitance, has good effects on improving the system stability. The measurement range of the airflow velocity is significantly increased when the electrode gap is 3 mm, coupling resistance is 470 Ω, and coupling capacitance is 220 pF.

  5. Double Glow Plasma Surface Alloyed Burn-resistant Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ping-ze; XU Zhong; HE Zhi-yong; ZHANG Gao-hui

    2004-01-01

    Conventional titanium alloy may be ignited and burnt under high temperature, high pressure and high gas flow velocity condition. In order to avoid this problem, we have developed a new kind of burn-resistant titanium alloy-double glow plasma surface alloying burn-resistant titanium alloy. Alloying element Cr, Mo, Cu are induced into the Ti-6Al-4V and Ti-6.5Al-0.3Mo-l.5Zr-0.25Si substrates according to double glow discharge phenomenon, Ti-Cr ,Ti-Mo, Ti-Cu binary burn-resistant alloy layers are formed on the surface of Ti-6Al-4V and Ti-6.5Al-0.3Mo-l.5Zr-0.25Si alloys. The depth of the surface burn-resistant alloy layer can reach to above 200 microns and alloying element concentration can reach 90%.Burn-resistant property experiments reveal that if Cr concentration reach to 14%, Cu concentration reach to 12%, Mo concentration reach to 10% in the alloying layers, ignition and burn of titanium alloy can be effectively avoided.

  6. Double Glow Plasma Surface Alloyed Burn-resistant Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    ZHANGPing-ze; XUZhong; HEZhi-yong; ZHANGGao-hui

    2004-01-01

    Conventional titanium alloy may be ignited and burnt under high temperature, high pressure and high gas flow velocity condition. In order to avoid this problem, we have developed a new kind of burn-resistant titanium alloy-double glow plasma surface alloying burn-resistant titanium alloy. Alloying element Cr, Mo, Cu are induced into the Ti-6A1-4V and Ti-6.5Al-0.3Mo-1.5Zr-0.25Si substrates according to double glow discharge phenomenon, Ti-Cr ,Ti-Mo, Ti-Cu binary burn-resistant alloy layers are formed on the surface of Ti-6A1-4V and Ti-6.5Al-0.3Mo-1.5Zr-0.25Si alloys. The depth of the surface burn-resistant alloy layer can reach to above 200 microns and alloying element concentration can reach 90%. Burn-resistant property experiments reveal that if Cr concentration reach to 14%, Cu concentration reach to 12%, Mo concentration reach to 10% in the alloying layers, ignition and burn of titanium alloy can be effectively avoided.

  7. COMPOSITION AND STRUCTURAL STUDIES OF STRONG GLOW DISCHARGE POLYMER COATINGS

    Energy Technology Data Exchange (ETDEWEB)

    CZECHOWICZ, DG; CASTILLO, ER; NIKROO, A

    2002-04-01

    OAK A271 COMPOSITION AND STRUCTURAL STUDIES OF STRONG GLOW DISCHARGE POLYMER COATINGS. An investigation of the chemical composition and structure of strong glow discharge (GDP) polymer shells made for cryogenic experiments at OMEGA is described. The investigation was carried out using combustion and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The strongest coatings were observed to have the lowest hydrogen content or hydrogen/carbon H/C ratio, whereas the weakest coatings had the highest hydrogen content or H/C ratio. Chemical composition results from combustion were used to complement FTIR analysis to determine the relative hydrogen content of as-fabricated coatings. Good agreement was observed between composition results obtained from combustion and FTIR analysis. FTIR analysis of coating structures showed the strongest coatings to have less terminal methyl groups and a more double bond or olefinic structure. Strong GDP coatings that were aged in air react more with oxygen and moisture than standard GDP coatings. In addition to a more olefinic structure, there may also be more free-radial sites present in strong GDP coatings, which leads to greater oxygen uptake.

  8. Multiple solutions in the theory of dc glow discharges

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, P G C; Benilov, M S; Faria, M J [Departamento de Fisica, Universidade da Madeira, Largo do Municipio, 9000 Funchal (Portugal)

    2010-04-15

    Multiple steady-state solutions existing in the theory of dc glow discharges are computed for the first time. The simulations are performed in 2D in the framework of the simplest self-consistent model, which accounts for a single ion species and employs the drift-diffusion approximation. Solutions describing up to nine different modes were found in the case where losses of the ions and the electrons due to diffusion to the wall were neglected. One mode is 1D, exists at all values of the discharge current, and represents in essence the well-known solution of von Engel and Steenbeck. The other eight modes are axially symmetric, exist in limited ranges of the discharge current, and are associated with different patterns of current spots on the cathode. The mode with a spot at the centre of the cathode exhibits a well pronounced effect of normal current density. Account of diffusion losses affects the solutions dramatically: the number of solutions is reduced, a mode appears that exists at all discharge currents and comprises the Townsend, subnormal, normal and abnormal discharges. The solutions that exist in limited current ranges describe patterns, and these patterns seem to represent axially symmetric analogues of the 3D patterns observed in dc glow microdischarges in xenon.

  9. Modeling the breakdown and glow phases during ignition of HID lamps

    Energy Technology Data Exchange (ETDEWEB)

    Liland, K.B.; Peres, I.; Pitchford, L.C.; Boeuf, J.P. [Univ. Paul Sabatier, Toulouse (France)

    1996-12-31

    HID lamps are often ignited by one or more short, high voltage pulses (trigger pulses) superimposed on the low frequency, generator voltage. The authors have developed a self-consistent, fluid model of transient glow discharges to study the breakdown and glow phases in HID lamps from the time of the application of the trigger pulse(s) to the time when there is a fully-developed, quasi-steady state glow discharge. The transition to the thermionic arc is not considered here. Using this model they have investigated the influence of the height, width and number of trigger pulses on the generator voltage required to achieve a steady-state glow discharge. The model used is one-dimensional, and the fundamental variables are the charged particle densities and the potential as functions of distance between the electrodes and time. The minimum voltage needed to initiate a glow discharge, V{sub g}, decreases with increasing current during the trigger pulse and reaches a minimum which is a few volts above the steady-state glow voltage. Results in discharges in argon and argon/mercury mixtures will be presented showing the dependence of V{sub g} on the trigger pulse and on other discharge conditions (gas mixture, external circuit, ...). The calculated, steady-state glow current-voltage characteristic will also be presented.

  10. Mineralization of aqueous pentachlorophenolate by anodic contact glow discharge electrolysis

    Institute of Scientific and Technical Information of China (English)

    Haiming Yang; Meguru Tezuka

    2011-01-01

    Exhaustive mineralization of pentachlorophenolate ion (PCP) in phosphate buffer was carried out using anodic contact glow discharge electrolysis (CGDE), in which plasma was sustained between the electrolyte and anode. During CGDE, PCP degraded smoothly. The amount of total organic carbon decreased significantly, indicating the eventual conversion of the carbon atoms of benzene nucleus to inorganic carbons. Furthermore, chlorine atoms in PCP were liberated as chloride ions. As a primary intermediate product, 2,3,5,6-tetrachloro-1,4-benzoquinone was detected, and oxalate and formate as byproducts were also found. It was revealed that disappearance of PCP obeyed first-order kinetics. The reaction rate was generally unaffected by both O2 and inert gases in the cell, although it decreased by raising initial pH of solution. In addition, a plausible reaction pathway involving hydroxyl radical was proposed.

  11. Flush-mounted probe diagnostics for argon glow discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Liang, E-mail: xld02345@mail.ustc.edu.cn; Cao, Jinxiang; Liu, Yu; Wang, Jian; Du, Yinchang; Zheng, Zhe; Zhang, Xiao; Wang, Pi [Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Jin; Li, Xiao; Qin, Yongqiang; Zhao, Liang [Science and Technology on Space Physics Laboratory, Beijing 100076 (China)

    2014-09-15

    A comparison is made between plasma parameters measured by a flush-mounted probe (FP) and a cylindrical probe (CP) in argon glow discharge plasma. Parameters compared include the space potential, the plasma density, and the effective electron temperature. It is found that the ion density determined by the FP agrees well with the electron density determined by the CP in the quasi-neutral plasma to better than 10%. Moreover, the space potential and effective electron temperature calculated from electron energy distribution function measured by the FP is consistent with that measured by the CP over the operated discharge current and pressure ranges. These results present the FP can be used as a reliable diagnostic tool in the stable laboratory plasma and also be anticipated to be applied in other complicated plasmas, such as tokamaks, the region of boundary-layer, and so on.

  12. Growth of ordered dusty structures in the glow discharge

    CERN Document Server

    Khakhaev, A; Khakhaev, Anatoly; Podriadtchikov, Sergey

    2004-01-01

    In plasma of direct-current glow discharge the dependence of ordered dusty structure volume, shape and density on plasma conditions were investigated. The structure is formed in a field of volume charge. In experimental investigations we used the aluminum oxide macroparticles with diameter up to 60 microns (size distribution function was not determined). Discharge tube was established vertically, has an internal diameter 2.6 cm and space gap between electrodes 45 cm. Particles were injected from the top end of the discharge tube into the plasma of spectral purity neon. Repeatability of randomized experiment results was better than 5% of the measured values. The areas of existence of various dusty ordered structures and their dependence on physical conditions in plasma (discharge current and pressure) were determined. When the interparticle distance in the structure is constant and particle positions have good time stability this structure was defined like "plasma crystal". Otherwise, we observed process of th...

  13. Degradation of linear alkylbenzene sulfonate with contact glow discharge electrolysis

    Science.gov (United States)

    Budikania, Trisutanti; Ibrahim, Febiyanti, Irine Ayu; Utami, Nissa; Saksono, Nelson

    2015-12-01

    Contact Glow Discharge Electrolysis (CGDE) is one of electrolysis plasma technologies. CGDE can produce the hydroxyl radical in a large amount that can be used for wastewater degradation process. This study was conducted to obtain the influence of applied voltage, electrolyte concentration, and anode depth in the LAS degradation using CGDE and review its energy consumption. The greatest LAS degradation is achieved up to 99.14% with low energy consumption of 1149.88 kJ/mmol of the energy consumption that is obtained during 120 minutes by using 600 Volt, 0.02 M of KOH, and 0.5 cm of the anode depth and initial concentration of LAS is 100 ppm.

  14. Glow discharges with electrostatic confinement of fast electrons

    Science.gov (United States)

    Kolobov, V. I.; Metel, A. S.

    2015-06-01

    This review presents a unified treatment of glow discharges with electrostatic confinement of fast electrons. These discharges include hollow cathode discharges, wire and cage discharges, reflect discharges with brush and multirod cathodes, and discharges in crossed electric and magnetic fields. Fast electrons bouncing inside electrostatic traps provide efficient ionization of gas at very low gas pressures. The electrostatic trap effect (ETE) was first observed by Paschen in hollow cathode discharges almost a century ago. The key parameters that define fundamental characteristics of ETE discharges are the ionization length λN, the penetration range, Λ, and the diffusion length λ of the fast electrons, and two universal geometric parameters of the traps: effective width a and length L. Peculiarities of electron kinetics and ion collection mechanism explain experimental observations for different trap geometries. The ETE is observed only at Λ > a, when the penetration range of the γ-electrons emitted by the cathode exceeds the trap width. In the optimal pressure range, when λN > a, and Λ current, Uc tends to its upper limit W/eβγ, where β is the percentage of ions arriving at the cathode and W is the gas ionization cost. In the low-pressure range, Λ > L, Uc rises from hundreds to thousands of volts. The sign of the anode potential fall, Ua, depends on the anode surface Sa and its position. When Sa is large compared to a critical value S*, Ua is negative and small. At Sa value of Ua becomes positive and rises up to 0.5-1 kV with decreasing p ultimately causing discharge extinction. Scaling laws indicate common physics between vacuum discharges and atmospheric pressure micro-discharges. We discuss peculiarities of electron kinetics under different conditions using semi-analytical models. Recent experimental results and applications of glow discharges with electrostatic confinement of fast electrons are described.

  15. Aspects of Metal Surface Glowing Mechanisms with Intensive Electron Beam Bombardment

    Directory of Open Access Journals (Sweden)

    I.V. Barsuk

    2012-06-01

    Full Text Available The paper gives a brief description and analysis of the main physical processes which can have an effect on the glowing nature of metal element surfaces in different electric vacuum devices when they are bombarded by electron beams. It has been found that the electron glowing effects on metal surfaces according to the electron energy can be explained with the help of the transition scattering on plasma waves or just with the classical transition radiation effect. This fact is rather important in terms of classical physics interpretation of the observed glowing effects on metal surface elements and techniques optimization of metal and electron beams diagnostics as well.

  16. Note: Rapid reduction of graphene oxide paper by glow discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Bo, Zheng; Qian, Jiajing; Duan, Liangping; Qiu, Kunzan, E-mail: qiukz@zju.edu.cn; Yan, Jianhua; Cen, Kefa [State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Han, Zhao Jun [CSIRO Manufacturing Flagship, P.O. Box 218, Bradfield Road, Lindfield, New South Wales 2070 (Australia); Ostrikov, Kostya [CSIRO Manufacturing Flagship, P.O. Box 218, Bradfield Road, Lindfield, New South Wales 2070 (Australia); Institute for Future Environments and School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland 4000 (Australia)

    2015-05-15

    This note reports on a novel method for the rapid reduction of graphene oxide (GO) paper using a glow discharge plasma reactor. Glow discharge is produced and sustained between two parallel-plate graphite electrodes at a pressure of 240 mTorr. By exposing GO paper at the junction of negative-glow and Faraday-dark area for 4 min, the oxygen-containing groups can be effectively removed (C/O ratio increases from 2.6 to 7.9), while the material integrality and flexibility are kept well. Electrochemical measurements demonstrate that the as-obtained reduced GO paper can be potentially used for supercapacitor application.

  17. Surface modification of polyester film by glow discharge tunnel at atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    XU Xiang-yu; WANG Shou-guo; YE Tian-chun; JING Guang-yin; YU Da-peng

    2004-01-01

    A large-area improved dielectric barrier glow discharge tunnel has been developed for modifying the surface of polyester film at atmospheric pressure with argon and oxygen gas mixtures. The electrical properties of the glow discharge tunnel were studied by simultaneous measurement of the voltage and current. In addition, the effect of the glow discharge tunnel treatment on the surface of polyester film were studied. The resultant modifications of the surface properties of the treated samples were investigated through scanning probe microscopy and contact angle measurement.

  18. A single TiO2-coated side-glowing optical fiber for photocatalytic wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    HU Yan; XU Jingjing; YUAN Chunwei; LIN Jian; YIN Zhidong

    2005-01-01

    By means of TiO2-layer-on-SiO2-layer, anatase TiO2 was deposited on novel side- glowing optical fibers, which can provide side UV radiation along the whole fiber length. FE-SEM images show that the double layers adhered well to the side-glowing optical fiber, and the TiO2 coating was homogeneous and smooth. The decomposition reaction of reactive brilliant red dye X-3B on a single TiO2-coated side-glowing optical fiber indicated that the side-scattering UV light intensity was strong enough for photocatalytic oxidation reaction. Therefore, TiO2-coated side-glowing optical fibers open up a new way to use the optical fiber reactor in photocatalytic wastewater treatment.

  19. Effect of Ne Glow Discharge on Ion Density Control in LHD

    Institute of Scientific and Technical Information of China (English)

    S.Morita; M. Goto; S. Masuzaki; H. Suzuki; K. Tanaka; H. Nozato; Y. Takeiri; J. Miyazawa; LHD esperimental group

    2004-01-01

    Neon glow discharge cleaning was firstly attempted in Large Helical Device (LHD) instead of He glow discharge to remove hydrogen neutrals and to control the ion density, ni. The Ne glow discharge continued for 8 hours overnight after a three-day experiment. At the second night Halpha emission became weaker than the emission usually observed in the He glow discharge. A clear reduction of the hydrogen influx was also observed in neutral beam injection (NBI) discharges with Ne puff, whereas the neon recycling was strongly enhanced with appearance of a flat density profile. As a result, the lowest density limit was further reduced down to 0.2 times10 13 ,cm-3. The use of Ar puff formed a peaked density profile with a high Ti of 7 keV.

  20. 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...

  1. The Effects of Lamp Spectral Distribution on Sky Glow over Observatories

    Science.gov (United States)

    2015-01-01

    MAR 2015 2. REPORT TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE The Effects of Lamp Spectral Distribution on Sky Glow...overhead sky glow as a function of distance up to 300 km, from a variety of lamp types, including common gas discharge lamps and several types of LED... lamps . We conclude for both professional, and especially cultural (visual), astronomy, that low-pressure sodium and narrowspectrum amber LED lamps

  2. Modeling of asymmetric pulsed phenomena in dielectric-barrier atmospheric-pressure glow discharges

    Energy Technology Data Exchange (ETDEWEB)

    Ha Yan [College of Mathematics and Computer Science, Hebei University, Baoding 071002 (China); Wang Huijuan [School of Mathematics and Physics, North China Electric Power University, Baoding 071003 (China); Wang Xiaofei [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)

    2012-01-15

    Asymmetric current pulses in dielectric-barrier atmospheric-pressure glow discharges are investigated by a self-consistent, one-dimensional fluid model. It is found that the glow mode and Townsend mode can coexist in the asymmetric discharge even though the gas gap is rather large. The reason for this phenomenon is that the residual space charge plays the role of anode and reduces the gap width, resulting in the formation of a Townsend discharge.

  3. The Effects of Lamp Spectral Distribution on Sky Glow over Observatories

    Science.gov (United States)

    Luginbuhl, C. B.; Boley, P. A.; Davis, D. R.; Duriscoe, D. M.

    2015-03-01

    Using a wavelength-generalized version of the Garstang (1991) model, we evaluate overhead sky glow as a function of distance up to 300 km, from a variety of lamp types, including common gas discharge lamps and several types of LED lamps. We conclude for both professional, and especially cultural (visual), astronomy, that low-pressure sodium and narrow-spectrum amber LED lamps cause much less sky glow than all broad-spectrum sources.

  4. Effects of norms, warm-glow and time use on household recycling

    OpenAIRE

    Halvorsen, Bente

    2004-01-01

    Abstract: The aim of this paper is to quantify the relative importance of motivations based on warm-glow, social and moral norms and cost of time used recycling on household recycling efforts. We also test for crowding-out of intrinsic motivations when recycling is perceived as mandatory. We find that the most important variable increasing household recycling efforts is agreeing that recycling is a pleasant activity in itself, which may be interpreted as a warm-glow effect. The...

  5. Second Order Fluid Glow Discharge Model Sustained by Different Source Terms%Second Order Fluid Glow Discharge Model Sustained by Different Source Terms

    Institute of Scientific and Technical Information of China (English)

    D. GUENDOUZ; A. HAMID; A. HENNAD

    2011-01-01

    Behavior of charged particles in a DC low pressure glow discharge is studied. The electric properties of the glow discharge in argon, maintained by a constant source term with uni- form electron and ion generation, between two plane electrodes or by secondary electron emission at the cathode, are determined. A fluid model is used to solve self-consistently the first three moments of the Boltzmann equation coupled with the Poisson equation. The stationary spatial distribution of the electron and ion densities, the electric potential, the electric field, and the electron energy, in a two-dimensional (2D) configuration, are presented.

  6. 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.

  7. 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.

  8. [Spatial distribution of electrons with high energy in atmospheric pressure glow discharge excited by DC voltage].

    Science.gov (United States)

    Liu, Zhi-qiang; Jia, Peng-ying; Liu, Tie

    2013-09-01

    Atmospheric pressure glow discharge excited by a DC voltage was realized in a 6 mm air gap by using a needle-water electrode discharge device. The atompheric pressure glow discharge has characteristic regions such as a cathode fall, a negative glow, a Faraday dark space, a positive column and an anode glow. The discharge is a normal glow through analyzing its voltage-current curve. The emission intensity of 337.1 nm spectral line from the second positive system of N2 was investigated because it can indicate the electron density with high energy. Results show that the maxima of high energy electrons appears in the vicinity of the needle tip, and it almost remains constant at other locations. The density of high energy electrons decreases with increasing the voltage. Similarly, it decreases with increasing the value of the ballast resistor. Oxygen atom is important for the sterilization and disinfection. The distribution of oxygen atom was also investigated by optical emission spectroscopy. It was found that the oxygen distribution is similar with the distribution of high energy electrons. These results are important for the application of atmospheric pressure glow discharge in environmental protection and biological treatment.

  9. 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.

  10. Degradation of Anionic Dye Eosin by Glow Discharge Electrolysis Plasma

    Institute of Scientific and Technical Information of China (English)

    GAO Jinzhang; MA Dongping; GUO Xiao; WANG Aixiang; FU Yan; WU Jianlin; YANG Wu

    2008-01-01

    This paper describes a novel method for the degradation of eosin by using glow discharge electrolysis (GDE). The effects of various parameters on the removal efficiency were studied. It was found that the eosin degradation could be raised considerably by increasing the applied voltage and the initial concentration, or by decreasing pH of the aqueous solution. Fe2+ ion had an evident accelerating effect on the eosin degradation. The degradation process of eosin obeyed a pseudo-first-order reaction. The relationship between the degradation rate constant κ and the reaction temperature T could be expressed by Arrhenius equation with which the apparent activation energy Ea of 14.110 kJ. Mol-1 and the pre-exponential factor k0 of 2.065×10-1 min-1 were obtained, too. The determination of hydroxyl radical was carried out by using N, N-dimethyl -p-nitrosoaniline (RNO) as a scavenger. The results showed that the hydroxyl radical plays an important role in the degradation process.

  11. Aqueous organic dye discoloration induced by contact glow discharge electrolysis.

    Science.gov (United States)

    Wang, Lei

    2009-11-15

    In this study, effects of applied voltage, types of electrolytes, initial substrate concentration, radical scavengers and iron salts on the aqueous polar brilliant B (PBB) discoloration induced by contact glow discharge electrolysis (CGDE) were examined. Experimental results showed that the PBB discoloration proceeded faster in chloride solution than in phosphate or sulfate solutions. Increasing the applied voltage from 450V to 550V did not enhance the discoloration when the applied current was kept constant. Addition of a small amount of hydroxyl scavengers (methanol) to the solution decreased the discoloration, whereas addition of a large amount of methanol increased the discoloration. During the treatment, TOC of the solution smoothly decreased whereas COD of the solution gradually increased due to the production of H(2)O(2) in the liquid phase. Iron salts enhanced the discoloration significantly due to the additional Fenton reaction. Higher initial PBB concentration resulted in lower color removal efficiency, indicating that the PBB discoloration by CGDE did not observe the first-order reaction kinetics in inert electrolytic solutions.

  12. Platinum and Iridium Coatings Obtained by Double Glow Plasma Technology

    Institute of Scientific and Technical Information of China (English)

    WU Wangping; CHEN Zhaofeng; CHEN Zhou; CONG Xiangna; QIU Jinlian

    2012-01-01

    Pt and Ir coatings were produced by double glow plasma technology on the surface of Ti alloy substrates.The chemical compositions of the coatings were determined by X-ray diffraction and X-ray photoelectron spectroscopy.The microstructure and morphology of the coatings were observed by scanning electron microscopy.The hardness and elastic modulus of the coatings were estimated by nanoindentation.The measurements of adhesive forces of the coatings were performed with scratch tester.The results indicated that the Pt and Ir coatings displayed the preferred (220) orientation due to the initial nuclei with preferred growth on the surface of the substrates.The interface between the Pt coating and substrate exhibited no evidence of delamination.The Ir coating was composed of irregular columnar grains with many nanovoids at the interface between the coating and substrate.The mean values of hardness for Pt and Ir coatings were 0.9 GPa and 9 GPa,respectively.The elastic modulus of Pt and Ir coatings were 178 GPa and 339 GPa,respectively.The adhesive forces of the Pt and Ir coatings were about 66.4 N and 55 N,respectively.The Pt and Ir coatings adhered well to the Ti alloy substrates.

  13. Non-Thermal Equilibrium Atmospheric Pressure Glow-Like Discharge Plasma Jet

    Science.gov (United States)

    Chang, Zhengshi; Yao, Congwei; Zhang, Guanjun

    2016-01-01

    Non-thermal equilibrium atmospheric pressure plasma jet (APPJ) is a cold plasma source that promises various innovative applications, and the uniform APPJ is more favored. Glow discharge is one of the most effective methods to obtain the uniform discharge. Compared with the glow dielectric barrier discharge (DBD) in atmospheric pressure, pure helium APPJ shows partial characteristics of both the glow discharge and the streamer. In this paper, considering the influence of the Penning effect, the electrical and optical properties of He APPJ and Ar/NH3 APPJ were researched. A word “Glow-like APPJ” is used to characterize the uniformity of APPJ, and it was obtained that the basic characteristics of the glow-like APPJ are driven by the kHz AC high voltage. The results can provide a support for generating uniform APPJ, and lay a foundation for its applications. supported by National Natural Science Foundation of China (Nos. 51307133, 51125029, 51221005) and the Fundamental Research Funds for the Central Universities of China (Nos. xjj2012132, xkjc2013004)

  14. Apocenter glow in eccentric debris disks: implications for Fomalhaut and $\\epsilon$ Eridani

    CERN Document Server

    Pan, Margaret; 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 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 ACTA should be reinterpreted as suggestions or examples of apocenter glow. This reinterpretation yields new constraints on the disks' dust grain properties and size distributions.

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

    Institute of Scientific and Technical Information of China (English)

    LI Xue-Chen; WANG Long

    2005-01-01

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

  16. 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.

  17. Self-Consistent Model for Pulsed Direct-Current N2 Glow Discharge

    Institute of Scientific and Technical Information of China (English)

    Liu Chengsen; Wang Dezhen

    2005-01-01

    A self-consistent analysis of a pulsed direct-current (DC) N2 glow discharge is presented. The model is based on a numerical solution of the continuity equations for electron and ions coupled with Poisson's equation. The spatial-temporal variations of ionic and electronic densities and electric field are obtained. The electric field structure exhibits all the characteristic regions of a typical glow discharge (the cathode fall, the negative glow, and the positive column).Current-voltage characteristics of the discharge can be obtained from the model. The calculated current-voltage results using a constant secondary electron emission coefficient for the gas pressure 133.32 Pa are in reasonable agreement with experiment.

  18. Study of the Effect of Decrease in the Conductivity Ahead of a Shock Wave in a Glow-Discharge Plasma

    Science.gov (United States)

    Baryshnikov, A. S.; Basargin, I. V.; Bobashev, S. V.; Monakhov, N. A.; Popov, P. A.; Sakharov, V. A.; Chistyakova, M. V.

    2016-05-01

    The electrical conductivity of a glow-discharge plasma ahead of a shock wave moving perpendicularly to the discharge axis has been investigated using a double electric probe. The obtained results have shown that the interaction of the shock wave with the glow-discharge plasma is accompanied by a change in its conductivity in the entire investigated volume simultaneously.

  19. Computational modeling of glow discharge-induced fluid dynamics

    Science.gov (United States)

    Jayaraman, Balaji

    Glow discharge at atmospheric pressure using a dielectric barrier discharge can induce fluid flow and operate as an actuator for flow control. The largely isothermal surface plasma generation realized above can modify the near-wall flow structure by means of Lorentzian collisions between the ionized fluid and the neutral fluid. Such an actuator has advantages of no moving parts, performance at atmospheric conditions and devising complex control strategies through the applied voltage. However, the mechanism of the momentum coupling between the plasma and the fluid flow is not yet adequately understood. In the present work, a modeling framework is presented to simulate athermal, non-equilibrium plasma discharges in conjunction with low Mach number fluid dynamics at atmospheric pressure. The plasma and fluid species are treated as a two-fluid system exhibiting a few decades of length and time scales. The effect of the plasma dynamics on the fluid dynamics is devised via a body force treatment in the Navier-Stokes equations. Two different approaches of different degrees of fidelity are presented for modeling the plasma dynamics. The first approach, a phenomenological model, is based on a linearized force distribution approximating the discharge structure, and utilizing experimental guidance to deduce the empirical constants. A high fidelity approach is to model the plasma dynamics in a self-consistent manner using a first principle-based hydrodynamic plasma model. The atmospheric pressure regime of interest here enables us to employ local equilibrium assumptions, signifying efficient collisional energy exchange as against thermal heating from inelastic collision processes. The time scale ratios between convection, diffusion, and reaction/ionization mechanisms are O(107), making the system computationally stiff. To handle the stiffness, a sequential finite-volume operator-splitting algorithm capable of conserving space charge is developed; the approach can handle time

  20. 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

    A great issue of concern in valuation studies is whether respondents provide trustworthy and reliable answers conditional on the perceived information. Respondent may report either a higher than the true Willingness-To-Pay (WTP) due to warm glow or embedding effects or zero WTP which is lower than...... 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...

  1. Research progress in the study of atmospheric pressure glow barrier discharge

    Institute of Scientific and Technical Information of China (English)

    LI Xuechen; DONG Lifang; JIA Pengying

    2007-01-01

    Atmospheric pressure glow barrier discharge (APGBD) can operate at high pressure, and so vacuum device is not necessary. Furthermore, the produced plasma by APGBD has moderate electron temperature and density besides good uniformity. Therefore,APGBD has extensive potential applications in industry and has been becoming a hot issue in the research of low temperature plasma. In this paper, the main problems in the study of atmospheric pressure glow discharge generated by dielectric barrier discharge, including the experimental setup, judging criterion, discharging conditions, physical mechanisms, and parameter diagnoses, are discussed, and further research prospects of APGBD are proposed.

  2. Characteristics of liquid flow induced by atmospheric-pressure DC glow discharge in contact with liquid

    Science.gov (United States)

    Tochikubo, Fumiyoshi; Aoki, Takuya; Shirai, Naoki; Uchida, Satoshi

    2017-04-01

    In this work, we investigated the characteristics of liquid flow induced by atmospheric-pressure dc glow discharge in contact with a liquid. The spatiotemporal development of liquid flow was visualized by the schlieren method, and the temperature distribution was measured using microencapsulated thermotropic liquid crystal particles dispersed in a liquid. We confirmed the appearance of specific downward liquid flow immediately below the dc glow discharge. The characteristics of downward liquid flow were reproduced by fluid simulation considering a downward driving force at the plasma–liquid interface. Our results suggest that the probable driving force for the downward liquid flow was the momentum transfer of charged species at the liquid surface.

  3. A STUDY OF THE POLYMERIZATION MECHANISM OF ACETONITRILE IN GLOW DISCHARGE

    Institute of Scientific and Technical Information of China (English)

    YU Qingsong; YE Mu; LU Lizhen; CHEN Jie; WANG Fosong; Yoshihito Osada

    1988-01-01

    Plasma polymerization of acetonitrile was carried out by a capacitively coupled RF plasma apparatus with external electrodes under some different reaction conditions such as discharge power. By investigating the informations provided by the polymer deposition regularities, IR spectra and elementary analysis results,the polymerization mechanism of acetonitrile in glow discharge have been investigated. The results show that acetonitrile polymerized in glow discharge mainly through hydrogen detachment for initiation at lower energy levels and the role that opening C = N triple bond played in polymerization became more important at higher energy levels.

  4. Progress in the understanding of non-1D glow discharges: experiment and theory

    Energy Technology Data Exchange (ETDEWEB)

    Derouard, J. [Laboratoire de Spectrometrie Physique (UA CNRS 08), Universite Joseph Fourier (Grenoble-I), BP 87, 38402 Saint Martin d`Heres (France); Pitchford, L. [Centre de Physique des Plasmas et Applications de Toulouse (UA CNRS 277), Universite Paul Sabatier, 31062 Toulouse (France)

    1996-03-01

    This contribution is a joint presentation on the structure of non unidimensional glow discharges experimentally observed using in particular optical diagnostics and predicted using self consistent numerical models. Results are presented concerning the effect of radial losses and electrode edges on the structure of DC and RF glow discharges, and the inititation phase of the breakdown in planar hollow cathode discharges. Most of the observed features of the discharges can be well reproduced by the models, which thus can be used to predict the effect of geometry on plasma devices and guide the optimization of their design. {copyright} {ital 1996 American Institute of Physics.}

  5. 110° C thermoluminescence glow peak of quartz – A brief review

    Indian Academy of Sciences (India)

    D K Koul

    2008-12-01

    The 110°C glow peak of quartz, though unstable at room temperature, has worked wonderfully in archaeology and retrospective dosimetry due to its pre-dose sensitization property. Various aspects of the peak, like its nature, defect centres involved, the impact of different stimuli and its application have been extensively studied. The main aims of this review are to (i) summarize briefly the work carried out on the various facets of this TL glow peak during the last four decades and (ii) identify the areas which need further attention in order to have a better understanding of the luminescence characteristics of this TL peak.

  6. A study of glow-discharge and permeation techniques for extraterrestrial oxygen beneficiation

    Science.gov (United States)

    Ash, R. L.; Wu, D.; Outlaw, R. A.

    1994-01-01

    Extraction of oxygen from Martian atmosphere and compression of lunar oxygen can utilize stabilized zirconia electrochemical pumps. Silver membranes can be used as electrodes to increase oxygen yield at relatively low temperatures. This study has investigated oxygen permeation through Ag 0.05Zr membranes with glow-discharge assisted disassociation. Data show that the overall process is controlled by bulk diffusion but the slow dissociative adsorption onto the surface limited the overall transport substantially. With glow-discharge assisted dissociation, an order of magnitude increase in oxygen throughput can be produced at relatively low temperatures (450-550C).

  7. Detrapping of tungsten nanoparticles in a direct-current argon glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Couëdel, L., E-mail: lenaic.couedel@univ-amu.fr; Kumar, K. Kishor; Arnas, C. [Laboratoire de Physique des Interactions Ioniques et Moléculaires, CNRS, Aix-Marseille Université, 13397 Marseille (France)

    2014-12-15

    Nanoparticles are grown from the sputtering of a tungsten cathode in a direct current argon glow discharge. Laser light scattering of a vertical laser sheet going through the plasma reveals that the dust particle cloud is compressed and pushed towards the anode during the discharge. Scanning electron microscopy images of substrates exposed to the plasma for given durations show that dust particles are continuously falling down on the anode during the discharge. These observations are explained by the fact that the electrostatic force at the negative glow-anode sheath boundary cannot balance the ion drag, gravity, and thermophoresis forces for particles of more than a few tens of nanometres in diameter.

  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. Thermoluminescence glow curve involving any extent of retrapping or any order of kinetics

    Indian Academy of Sciences (India)

    Jai Prakash

    2013-09-01

    Adirovitch set of equations has been modified to explain the mechanisms involved in thermoluminescence (TL) glow curve. 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 trapped electrons per unit volume are evaluated easily and conveniently. It has been observed that retrapping increases with increasing order of kinetics.

  10. Computerized glow curve deconvolution: the case of LiF TLD-100

    Energy Technology Data Exchange (ETDEWEB)

    Gartia, R.K.; Dorendrajit Singh, S.; Mazumdar, P.S. (Manipur Univ. (India). Dept. of Physics)

    1993-05-14

    It has been accepted by a large number of workers that the glow curve of LiF TLD (Thermoluminescent dosimetry)-100 can be described by thermoluminescence (TL) peaks following the Randall-Wilkins (RW) equation, even though the model fails to explain a number of experimental facts. A further simplification of the model is the Podgorsak-Moran-Cameron (PMC) approximation which is also in use. This paper points out the limitation of the PMC approximation in deconvoluting glow curves of LiF TLD-100. (author).

  11. The thermoluminescence glow curve and the deconvoluted glow peak characteristics of erbium doped silica fiber exposed to 70-130 kVp x-rays.

    Science.gov (United States)

    Alawiah, A; Bauk, S; Marashdeh, M W; Nazura, M Z N; Abdul-Rashid, H A; Yusoff, Z; Gieszczyk, W; Noramaliza, M N; Adikan, F R Mahamd; Mahdiraji, G A; Tamchek, N; Muhd-Yassin, S Z; Mat-Sharif, K A; Zulkifli, M I; Omar, N; Wan Abdullah, W S; Bradley, D A

    2015-10-01

    In regard to thermoluminescence (TL) applied to dosimetry, in recent times a number of researchers have explored the role of optical fibers for radiation detection and measurement. Many of the studies have focused on the specific dopant concentration, the type of dopant and the fiber core diameter, all key dependencies in producing significant increase in the sensitivity of such fibers. At doses of less than 1 Gy none of these investigations have addressed the relationship between dose response and TL glow peak behavior of erbium (Er)-doped silica cylindrical fibers (CF). For x-rays obtained at accelerating potentials from 70 to 130 kVp, delivering doses of between 0.1 and 0.7 Gy, present study explores the issue of dose response, special attention being paid to determination of the kinetic parameters and dosimetric peak properties of Er-doped CF. The effect of dose response on the kinetic parameters of the glow peak has been compared against other fiber types, revealing previously misunderstood connections between kinetic parameters and radiation dose. Within the investigated dose range there was an absence of supralinearity of response of the Er-doped silica CF, instead sub-linear response being observed. Detailed examination of glow peak response and kinetic parameters has thus been shown to shed new light of the rarely acknowledged issue of the limitation of TL kinetic model and sub-linear dose response of Er-doped silica CF.

  12. 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 water extracts of each device. The main analytical technique for identification of chemical compositions, amounts, and changes during sequential reference Endotoxin additions and subsequent RFGD-treatment removals from infrared (IR)-transparent germanium (Ge) prisms was Multiple Attenuated Internal Reflection (MAIR) infrared spectroscopy sensitive to even monolayer amounts of retained bio-contaminant. KimaxRTM 60 mm x 15 mm and 50mm x 15mm laboratory glass dishes and germanium internal reflection prisms were inoculated with E. coli bacterial endotoxin water suspensions at increments of 0.005, 0.05, 0.5, and 5 EU, and characterized by MAIR-IR spectroscopy of the dried residues on the Ge prisms and LAL Assay of sterile water extracts from both glass and Ge specimens. The Ge prism MAIR-IR measurements were

  13. 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...

  14. An efficient model to simulate stable glow corona discharges and their transition into streamers

    Science.gov (United States)

    Liu, Lipeng; Becerra, Marley

    2017-03-01

    A computationally efficient model to evaluate stable glow corona discharges and their transition into streamers is proposed. The simplified physical model referred to as the SPM is based on the classic hydrodynamic model of charge particles and a quasi-steady state approximation for electrons. The solution follows a two-step segregated procedure, which solves sequentially the stationary continuity equation for electrons and then time-dependent continuity equations for ions. The validity of using the SPM to simulate glow corona discharges and their transition into streamers is demonstrated by performing comparisons with a fully coupled physical model (FPM) and with experimental data available in the literature for air under atmospheric conditions. It is shown that the SPM can obtain estimates similar to those calculated with the FPM and those measured in experiments but using significantly less computation time. Since the proposed model simulates efficiently the ionization layer without prior knowledge of the surface electric field or the discharge current, it is a computationally efficient alternative to calculations of glow corona discharges based on Kaptzov’s approximation (KAM). The model can also be employed to efficiently calculate the conditions for the transition of glow corona into streamers, overcoming the limitations of KAM to provide such estimates.

  15. Qualitative gas temperature distribution in positive DC glow corona using spectral image processing in atmospheric air

    Science.gov (United States)

    Matsumoto, Takao; Inada, Yoichi; Shimizu, Daisuke; Izawa, Yasuji; Nishijima, Kiyoto

    2015-01-01

    An experimental method of determining a qualitative two-dimensional image of the gas temperature in stationary atmospheric nonthermal plasma by spectral image processing was presented. In the experiment, a steady-state glow corona discharge was generated by applying a positive DC voltage to a rod-plane electrode in synthetic air. The changes in the gas temperature distribution due to the amplitude of applied voltage and the ambient gas pressure were investigated. Spectral images of a positive DC glow corona were taken using a gated ICCD camera with ultranarrow band-pass filters, corresponding to the head and tail of a N2 second positive system band (0-2). The qualitative gas temperature was obtained from the emission intensity ratio between the head and tail of the N2 second positive system band (0-2). From the results, we confirmed that the gas temperature and its distribution of a positive DC glow corona increased with increasing applied voltage. In particular, just before the sparkover voltage, a distinctly high temperature region was formed in the positive DC glow at the tip of the rod electrode. In addition, the gas temperature decreased and its distribution spread diffusely with decreasing ambient gas pressure.

  16. A Study on Water Treatment Induced by Plasma with Contact Glow Discharge Electrolysis

    Institute of Scientific and Technical Information of China (English)

    胡中爱; 王晓艳; 高锦章; 邓华陵; 侯经国; 卢小泉; 康敬万

    2001-01-01

    Oxidative degradation of eight kinds of dyes induced by plasma in aqueous solution was investigated with contact glow discharge electrolysis (CGDE). It has been demonstrated that these eight dyes underwent degradation in CGDE, where Fe2+ could be utilised to raise the efficiency of degradation of dyes.

  17. The multisensor payload 'Structura' for the observation of atmospheric night glows from the ISS board

    Science.gov (United States)

    Krot, Yury; Beliaev, Boris; Katkovsky, Leonid

    2016-10-01

    Aerospace Research Department of the Institute of Applied Physical Problems at Belarusian State University has developed a prototype of the optical payload intended for a space experiment on the ISS board. The prototype includes four optical modules for the night glows observation, in particular spatial-brightness and spectral characteristics in the altitude range of 80-320 km. Objects of the interest are emitting top layers of the atmosphere including exited OH radicals, atomic and molecular oxygen and sodium layers. The goal of the space experiment is a research of night glows over different regions of the Earth and a connection with natural disasters like earthquakes, cyclones, etc. Two optical modules for spatial distribution of atomic oxygen layers along the altitude consist of input lenses, spectral interferential filters and line CCD detectors. The optical module for registration of exited OH radical emissions is formed from CCD array spectrometer. The payload includes also a panchromatic (400-900 nm) high sensitive imaging camera for observing of the glows general picture. The optical modules of the prototype have been tested and general optical characteristics were determined in laboratory conditions. A solution of an astigmatism reducing of a concave diffraction grating and a method of the second diffraction order correction were applied and improved spectrometer's optical characteristics. Laboratory equipment and software were developed to imitate a dynamic scene of the night glows in laboratory conditions including an imitation of linear spectra and the spatial distribution of emissions.

  18. Drift-diffusion model of normal glow discharge in an axial magnetic field

    Science.gov (United States)

    Surzhikov, S. T.

    2016-12-01

    A two-dimensional axisymmetrical computing model is formulated with using of which the mathematical modeling of the normal glow discharge in molecular hydrogen is fulfilled in an axial magnetic field with the induction B = 0.1 T in the pressure range p = 1.25-5 Torr and the current-source electromotive force E = 1-3 kV.

  19. Quantitative Analysis on Carbon Migration in Double-Glow Discharge Plasma Surface Alloying Process

    Institute of Scientific and Technical Information of China (English)

    ZHANGZhen-xia; WANGCong-zeng; ZHANGWen-quan; SUXue-kuan

    2004-01-01

    Carbon migration is of great significance in double-glow discharge plasma surface alloying process, but literature of quantitative analysis about carbon migration is relatively scarce. In this paper differential equations of the carbon and metal concentration distribution were established. By means of differential equations carbon migration was described and a numerical solution was acquired. The computational results fit the experiment results quite well.

  20. Evaluation of trapping parameter of quartz by deconvolution of the glow curves

    Energy Technology Data Exchange (ETDEWEB)

    Gartia, R.K. [Department of Physics, Manipur University, Imphal 795001 (India); Singh, L. Lovedy, E-mail: lovedyo1@yahoo.co.in [Department of Physics, Manipur University, Imphal 795001 (India)

    2011-08-15

    The glow curves of natural quartz excited with different doses of {beta}-irradiation have been subjected to Computerized Glow Curve Deconvolution (CGCD) in the kinetic formalism. The location of the constituent peaks, which are as many as eleven in the temperature region of 27-575 deg. C, has been ascertained by resorting to the second order derivative plot of the glow curve. Not only figure of merit (FOM) but {chi}{sup 2}-test has also been taken as a criterion for the acceptance of goodness of fit. CGCD analysis reveals that the frequency factor of quartz is in the range of 1.50 {+-} 0.26 x 10{sup 11} sec{sup -1}. This analysis lead to the conclusion that the trapping levels of quartz can be approximated by the Urbach's relation E = 27kT{sub m} where T{sub m} is the temperature at the maximum intensity. - Highlights: > Glow curves of natural and beta-irradiated quartz in the temperature range from room temperature to 573 deg. C is analysed. > Frequency factor of quartz is in the range of 1.50 {+-} 0.26 x 10{sup 11} sec{sup -1}. > Trapping levels of quartz can be approximated by the Urbach's relation E = 27kT{sub m}.

  1. Research of the Effects of Electron Focused Electric Field upon an Enhanced Glow Discharge Plasma Ion Implantation

    Institute of Scientific and Technical Information of China (English)

    LI Liu-he; WU Yong-qin; ZHANG Yan-hua; CAI Xun; CHU Paul K

    2004-01-01

    A new Enhanced Glow Discharge Plasma Ion Implantation methods are introduced, in which the plasma are produced by the self glow discharge excitated by high negative voltage bias. The electric field is designed to a electron focusing mode by using a small area hollow anode and a large area sample holder cathode. The pattern of equipotentials of the electric field are calculated through finite-element method. By using the special electron-focusing field, the self glow discharge are enhanced and provide denser ions to implanted into the substrate.

  2. 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.

  3. Development of On-Line Direct Current Glow Discharge Source for Analysis of Isotope Ratio of Hydrogen

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>The present research is focused on the analysis of isotope ratio of the hydrogen by measuring an intensity ratio of hydrogen/deuterium/tritium fluxes. The direct current glow discharge tube may provide a

  4. 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...

  5. Glow curves and the emission of flux-grown BaFCl:Na crystals. [X radiation and gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Somaiah, K.; Hari Babu, V. (Osmania Univ., Hyderabad (India). Dept. of Physics)

    1984-08-01

    The thermoluminescence glow curves and the emission spectra of flux-grown BaFCl:Na crystals were recorded. An additional TL peak at 320 K, an optical absorption band at 570nm and an emission peak at 490 nm have been seen in X/..gamma..-irradiated crystals. Bleaching, room-temperature annealing and high-temperature emission results led us to conclude that the sodium impurity is responsible for the additional glow peak optical absorption band and emission peak.

  6. Double Glow Plasma Hydrogen-free Carburizing on Commercial Purity Titanium

    Institute of Scientific and Technical Information of China (English)

    ZHANG Gaohui; PAN Junde; HE Zhiyong; ZHANG Pingze; GAO Yuan; XU Zhong

    2005-01-01

    A carburized layer with special physical and chemical properties was formed on the surface of commercial purity titanium by a double glow plasma hydrogen-free carburizing technique. High-purity netlike solid graphite was used as a raw material and commercial purity titanium was used as the substrate material. Argon gas was used as the working gas. The carburized layer can be obviously observed under a microscope. X-ray diffraction indicates that TiC phase with higher hardness and dissociate state carbon phase was formed in the carburized layer. The glow discharge spectrum (GDS) analysis shows that the carbon concentration distributes gradiently along the depth of carburized layer. The surface hardness of the substrate increases obviously. The hardness distributes gradiently from the surface to inner of carburized layer. The friction coefficient reduces by more than 1/2, the ratio wear rate decreases by above three orders of magnitude. The wear resistance of the substrate material is improved consumedly.

  7. Evidence for large-area superemission into a high-current glow discharge

    Science.gov (United States)

    Hartmann, W.; Dominic, V.; Kirkman, G. F.; Gundersen, M. A.

    1988-10-01

    This letter presents evidence for large-area (≊1 cm2) cathode superemission (˜10 000 A/cm2) into a high-current glow discharge in a pseudospark or back lighted thyratron switch. Cathodes studied with a scannning electron microscope following operation at 6-8 kA, ≊1 μs pulse length, and 105 pulses in a low-pressure H2 discharge show evidence of melting of a thin surface layer within a radius of ˜4 mm, indicating that the discharge is a superdense glow with a cross-sectional area of the order of 1 cm2, rather than an arc. Further supporting evidence is provided by streak camera data. An ion beam present during the avalanche phase of the discharge is responsible for heating the cathode surface resulting in a significant field-enhanced thermionic emission.

  8. Optimal length of capacitive-discharge and glow-discharge excilamps

    Science.gov (United States)

    Boichenko, A. M.; Erofeev, M. V.; Sosnin, E. A.; Tarasenko, V. F.; Yakovlenko, S. I.

    2007-06-01

    The optimal tube length of capacitive-discharge and glow-discharge excimer lamps with ring and circular electrodes of equal radii is considered. It is demonstrated that, at the same potential difference between electrodes and their radii, the ratio of the optimal lengths of the tubes with circular and ring electrodes depends on width L of the ring electrodes. The ratio of the lengths decreases with decreasing L. A relationship between the tube length and radius, the width of ring electrodes, and the minimum voltage at the tube that provide for an approximately uniform glow of the discharge column in the presence of voltage pulses with opposite polarities at the electrodes is derived.

  9. Canard-induced mixed mode oscillations in an excitable glow discharge plasmas

    CERN Document Server

    Nurujjaman, M

    2014-01-01

    We demonstrated experimentally canard induced mixed mode oscillations (MMO) in an excitable glow discharge plasma, and the results are validated through numerical solution of the FitzHugh Nagumo (FHN) model. When glow discharge plasma is perturbed by applying a magnetic field, it shows mixed mode oscillatory activity, i.e., quasiperiodic small oscillations interposed with large bounded limit cycles oscillations. The initial quasiperiodic oscillations were observed to change into large amplitude limit cycle oscillations with magnetic field, and the number of these oscillation increases with increase in the magnetic field. Fourier analysis of both numerical and experimental results show that the origin of these oscillations are canard-induced phenomena, which occurs near the threshold of the control parameter. Further, the phase space plots also confirm that the oscillations are basically canard-induced MMOs.

  10. Chaotic-to-ordered state transition of cathode-sheath instabilities in DC glow discharge plasmas

    Indian Academy of Sciences (India)

    Md Nurujjaman; A N Sekar Iyengar

    2006-08-01

    Transition from chaotic to ordered state has been observed during the initial stage of a discharge in a cylindrical DC glow discharge plasma. Initially it shows a chaotic behavior but increasing the discharge voltage changes the characteristics of the discharge glow and shows a period subtraction of order 7 period → 5 period → 3 period → 1 period, i.e. the system goes to single mode through odd cycle subtraction. On further increasing the discharge voltage, the system goes through period doubling, like 1 period → 2 period → 4 period. On further increasing the voltage, the system goes to stable state through two period subtraction, like 4 period → 2 period → stable.

  11. Uniqueness theorem for the non-local ionization source in glow discharge and hollow cathode

    CERN Document Server

    Gorin, Vladimir V

    2012-01-01

    The paper is devoted to the proof of the uniqueness theorem for solution of the equation for the non-local ionization source in a glow discharge and a hollow cathode in general 3D geometry. The theorem is applied to wide class of electric field configurations, and to the walls of discharge volume, which have a property of incomplete absorption of the electrons. Cathode is regarded as interior singular source, which is placed arbitrarily close to the wall. The existence of solution is considered also. During the proof of the theorem many of useful structure formulae are obtained. Elements of the proof structure, which have arisen, are found to have physical sense. It makes clear physical construction of non-local electron avalanche, which builds a source of ionization in glow discharge at low pressures. Last has decisive significance to understand the hollow cathode discharge configuration and the hollow cathode effect.

  12. Plasma Treatment of Polyethylene Powder Particles in Hollow Cathode Glow Discharge

    Science.gov (United States)

    Wolter, Matthias; Quitzau, Meike; Bornholdt, Sven; Kersten, Holger

    2008-09-01

    Polyethylen (PE) is widely used in the production of foils, insulators, packaging materials, plastic bottles etc. Untreated PE is hydrophobic due to its unpolar surface. Therefore, it is hard to print or glue PE and the surface has to be modified before converting. In the present experiments a hollow cathode glow discharge is used as plasma source which is mounted in a spiral conveyor in order to ensure a combines transport of PE powder particles. With this set-up a homogeneous surface treatment of the powder is possible while passing the glow discharge. The plasma treatment causes a remarkable enhancement of the hydrophilicity of the PE powder which can be verified by contact angle measurements and X-ray photoelectron spectroscopy.

  13. Characteristics of a Normal Glow Discharge Excited by DC Voltage in Atmospheric Pressure Air

    Science.gov (United States)

    Li, Xuechen; Zhao, Huanhuan; Jia, Pengying

    2013-11-01

    Atmospheric pressure glow discharges were generated in an air gap between a needle cathode and a water anode. Through changing the ballast resistor and gas gap width between the electrodes, it has been found that the discharges are in normal glow regime judged from the current-voltage characteristics and visualization of the discharges. Results indicate that the diameter of the positive column increases with increasing discharge current or increasing gap width. Optical emission spectroscopy is used to calculate the electron temperature and vibrational temperature. Both the electron temperature and the vibrational temperature increases with increasing discharge current or increasing gap width. Spatially resolved measurements show that the maxima of electron temperature and vibrational temperature appeared in the vicinity of the needle cathode.

  14. Isotope effects on desorption kinetics of hydrogen isotopes implanted into stainless steel by glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Matsuyama, M.; Kondo, M.; Noda, N. [Hydrogen Isotope Research Center, University of Toyama, Gofuku, Toyama (Japan); Tanaka, M.; Nishimura, K. [National Institute for Fusion Science, Toki-shi, Gifu (Japan)

    2015-03-15

    In a fusion device the control of fuel particles implies to know the desorption rate of hydrogen isotopes by the plasma-facing materials. In this paper desorption kinetics of hydrogen isotopes implanted into type 316L stainless steel by glow discharge have been studied by experiment and numerical calculation. The temperature of a maximum desorption rate depends on glow discharge time and heating rate. Desorption spectra observed under various experimental conditions have been successfully reproduced by numerical simulations that are based on a diffusion-limited process. It is suggested, therefore, that desorption rate of a hydrogen isotope implanted into the stainless steel is limited by a diffusion process of hydrogen isotope atoms in bulk. Furthermore, small isotope effects were observed for the diffusion process of hydrogen isotope atoms. (authors)

  15. Hardness and stress of amorphous carbon film deposited by glow discharge and ion beam assisting deposition

    CERN Document Server

    Marques, F C

    2000-01-01

    The hardness and stress of amorphous carbon films prepared by glow discharge and by ion beam assisting deposition are investigated. Relatively hard and almost stress free amorphous carbon films were deposited by the glow discharge technique. On the other hand, by using the ion beam assisting deposition, hard films were also obtained with a stress of the same order of those found in tetrahedral amorphous carbon films. A structural analysis indicates that all films are composed of a sp sup 2 -rich network. These results contradict the currently accepted concept that both stress and hardness are only related to the concentration of sp sup 3 sites. Furthermore, the same results also indicate that the sp sup 2 sites may also contribute to the hardness of the films.

  16. 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.

  17. 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.

  18. Analysis Of The Different Zones Of Glow Discharge Of Ethyl Alcohol (C2H6O)

    Science.gov (United States)

    Torres, C.; Reyes, P. G.; Mulia, J.; Castillo, F.; Martínez, H.

    2014-05-01

    The aim of this work is to explore the emission spectroscopy of ethyl alcohol in some regions, also is determine the result elements of the glow discharge, the spectrums were observed in a range of 200 at 1100 nm in the different zones inside of the tube at different distances of 20 and 30 cm. The elements are: in anode region C6H5 (483.02nm), CHO (519.56nm) and H2 (560.47nm), in the positive column CO2+ (315.52 y 337.00nm), O+ (357.48nm), CH+ (380.61nm) and CO+ (399.73nm); in the cathode region we observed O+ (391.19nm), CHOCHO (428.00nm), CO+ (471.12nm) and H2 (656.52nm). C6H5, CHO y H2 species occurring in all regions analyzed varying the glow discharge emission intensity.

  19. The glow duration time influence on the ionization rate detected in the diodes filled with noble gases on mbar pressures

    Directory of Open Access Journals (Sweden)

    Stepanović Olivera M.

    2003-01-01

    Full Text Available The results of the glow current duration time (glowing-time influence on the ionization rate detected in the gas filled diodes are presented. The electrical breakdown was detected as the minimal current impulse. After that diode glow from the minimal glowing-time (10-3 s, up to the maximal 103 s which overlap the time of the stationary regime formation in the gas diode tube. The diodes were with volumes of 300 cm3, but with a diode gap volume of about 1 cm3 and filled with helium, neon, argon or krypton, at the pressures of the order of mbar. The ionization rates were detected as the residual ionization after the glowing was interrupted, using the electrical breakdown time delay measuring method. The influence of the gap distance stationary current values and the relaxation period were also investigated. The result shows that the stationary regime in such a gas diode is established after the glowing time of 1-3 s, although the breakdown formative times were smaller then 1 ms.

  20. 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.

  1. Effect of Atmospheric Pressure Glow Discharge Treatment on Polymerization of Acrylic Fabric and Its Printing Behavior

    Directory of Open Access Journals (Sweden)

    D M El-Zeer

    2014-03-01

    Full Text Available Acrylic fibers have been treated by atmospheric pressure glow discharge (APGD plasma in open air to enhance surface antistatic properties. The treated surfaces are investigated by scanning electron microscopy (SEM, Fourier-Transition Infrared Spectroscopy (FTIR and Atomic Force Microscope (AFM. Plasma treatment of acrylic fabric has been found to increase the surface roughness, modify the nature and density of surface functionalities, and drastically improve the wettability and antistatic ability of acrylic fibers.

  2. A Monte Carlo Simulation for the Ion Transport in Glow Discharges with Dusts

    Institute of Scientific and Technical Information of China (English)

    SUN Ai-Ping; PU Wei; QIU Xiao-Ming

    2001-01-01

    We use the Monte Carlo method to simulate theion transport in the rf parallel plate glow discharge with a negative-voltage pulse connected to the electrode. It is found that self-consistent field, dust charge, dust concentration,and dust size influence the energy distribution and the density of the ions arriving at the target, and in particular, the latter two make significant influence. As dust concentration or dust size increases, the number of ions arriving at the target reduces greatly.

  3. 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.

  4. Numerical simulation of a direct current glow discharge in atmospheric pressure helium

    Science.gov (United States)

    Yin, Zeng-Qian; Wang, Yan; Zhang, Pan-Pan; Zhang, Qi; Li, Xue-Chen

    2016-12-01

    Characteristics of a direct current (DC) discharge in atmospheric pressure helium are numerically investigated based on a one-dimensional fluid model. The results indicate that the discharge does not reach its steady state till it takes a period of time. Moreover, the required time increases and the current density of the steady state decreases with increasing the gap width. Through analyzing the spatial distributions of the electron density, the ion density and the electric field at different discharge moments, it is found that the DC discharge starts with a Townsend regime, then transits to a glow regime. In addition, the discharge operates in a normal glow mode or an abnormal glow one under different parameters, such as the gap width, the ballast resistors, and the secondary electron emission coefficients, judged by its voltage-current characteristics. Project supported by the National Natural Science Foundation of China (Grant Nos. 11575050 and 10805013), the Midwest Universities Comprehensive Strength Promotion Project, the Natural Science Foundation of Hebei Province, China (Grant Nos. A2016201042 and A2015201092), and the Research Foundation of Education Bureau of Hebei Province, China (Grant No. LJRC011).

  5. Generation of uniform atmospheric pressure argon glow plasma by dielectric barrier discharge

    Indian Academy of Sciences (India)

    Raju Bhai Tyata; Deepak Prasad Subedi; Rajendra Shrestha; Chiow San Wong

    2013-03-01

    In this paper, atmospheric pressure glow discharges (APGD) in argon generated in parallel plate dielectric barrier discharge system is investigated by means of electrical and optical measurements. Using a high voltage (0–20 kV) power supply operating at 10–30 kHz, homogeneous and steady APGD has been observed between the electrodes with gap spacing from 0.5 mm to 2 mm and with a dielectric barrier of thickness 2 mm while argon gas is fed at a controlled flow rate of 11/min. The electron temperature and electron density of the plasma are determined by means of optical emission spectroscopy. Our results show that the electron density of the discharge obtained is of the order of 1016 cm-3 while the electron temperature is estimated to be 0.65 eV. The important result is that electron density determined from the line intensity ratio method and stark broadening method are in very good agreement. The Lissajous figure is used to estimate the energy deposited to the glow discharge. It is found that the energy deposited to the discharge is in the range of 20 to 25 $\\$J with a discharge voltage of 1.85 kV. The energy deposited to the discharge is observed to be higher at smaller gas spacing. The glow discharge plasma is tested to be effective in reducing the hydrophobicity of polyethylene film significantly.

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

    Science.gov (United States)

    Sarwar, Mirza Saquib us; Xiao, Zhiming; Saleh, Tanveer; Nojeh, Alireza; Takahata, Kenichi

    2016-08-01

    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.

  7. Ignition and dynamics of high-voltage glow discharge plasma implantation

    Science.gov (United States)

    Fu, Ricky K. Y.; Chu, Paul K.; Tian, X. B.; Yang, S. Q.

    2006-01-01

    The self-ignition and dynamics of glow discharge plasma in the pulsed high-voltage plasma immersion ion implantation mode have been investigated. After ignition during the pulse-on period, the glow discharge continues to be sustained for a long period of time after the high-voltage pulse has been turned off as monitored by a Langmuir probe. The glow discharge and ignition lie on the left side of the Paschen curve when pd (gas pressure times electrode separation) is adjusted by using different anode to cathode distances utilizing a conducting grounded grid. The increased or constant implantation current Ia reveals that the ion sheath is stable and conforms to the cathode structure as the plasma density increases by one to two orders of magnitude towards the anode. In addition, the duration of the post-pulse-off plasma can be as long as several times of the pulse duration. The ignition time and duration of the plasma depend on the working pressure, applied voltage and pulse duration.

  8. Quantification Approach of Gas Temperate Distribution in Atmospheric Positive DC Glow Discharge Measured by Spectroscopic Imaging

    Science.gov (United States)

    Sasamoto, Ryo; Orii, Hideaki; Matsumoto, Takao; Izawa, Yasuji; Nishijima, Kiyoto

    2015-09-01

    In our previous work, a two-dimensional (2D) gas temperature distribution in a positive DC steady-state glow corona was qualitatively measured by spectroscopic imaging. Spectral images of its glow corona were taken using ICCD camera with ultra-narrow band-pass filters, and they were corresponded to the head and tail of a second positive system bands of nitrogen (2PS N2 (0-2)). The qualitative gas temperature was obtained from the emission intensity ratio (I2 Ptail/I2 Phead) between the head and tail of 2PS N2 (0-2). This emission intensity ratio also equals the rotational temperature (TR) , and TR almost equals the gas temperature (TG) in atmospheric pressure. In this work, the qualitative 2D gas temperature distribution was derived from 2D I2 Ptail/I2 Phead plots, and the calibration date of I2 Ptail/I2 Phead for TR was accumulated by investigating the relationship between the spatially average absolute gas temperature (Tav) obtained by single-point spectroscopic measurement and the average value of I2 Ptail/I2 Phead plots. On the basis of the calibration date, a spectroscopically-imaged qualitative 2D I2 Ptail/I2 Phead distribution in a positive DC glow corona was converted to a quantitative 2D image of gas rotational temperature.

  9. FT Tokamak Upgrade (FTU) vacuum vessel section cleaning by glow discharge in hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Ciotti, M.; Apicella, M.L.; Verdini, L.; Ferro, C.

    1991-09-01

    The possibility of applying glow discharge in hydrogen for the cleaning of the FTU (Frascati Tokamak Upgrade) vacuum chamber was analyzed on a 1:1 scale toroidal section by using the same operating conditions as foreseen for the machine. The discharge was maintained for six hours in the chamber with the wall temperature kept at 150 degrees C. The partial pressures at the end of the cleaning run were compared with those obtained by using only thermal outgassing at the same temperature. A reduction of about a factor of two in the H/sub 2/0 and C0/sub 2/ partial pressures was observed, related to a better cleanness of the surface. It was found that the high temperature during the glow discharge cleaning not only increases the efficiency of the discharge, but it is an efficient tool to remove impurities from the hidden regions, defined by the thermal shields that cover all the vacuum vessel walls not directly exposed to the glow discharge.

  10. Development and synthesis of durable self-glowing crystals doped with plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Burakov, B.E. [Laboratory of Applied Mineralogy and Radiogeochemistry, V.G. Khlopin Radium Institute, 2nd Site, 1, Rentgena Street, St. Petersburg 197101 (Russian Federation); Domracheva, Ya.V. [Ioffe Physico-Technical Institute, Russian Academy of Sciences, 26, Polytekhnicheskaya Street, St. Petersburg 194021 (Russian Federation)], E-mail: y.domracheva@mail.ioffe.ru; Zamoryanskaya, M.V. [Ioffe Physico-Technical Institute, Russian Academy of Sciences, 26, Polytekhnicheskaya Street, St. Petersburg 194021 (Russian Federation); Petrova, M.A.; Garbuzov, V.M.; Kitsay, A.A.; Zirlin, V.A. [Laboratory of Applied Mineralogy and Radiogeochemistry, V.G. Khlopin Radium Institute, 2nd Site, 1, Rentgena Street, St. Petersburg 197101 (Russian Federation)

    2009-03-15

    Different crystalline materials doped with plutonium and other alpha-emitting radionuclides are characterized by self-glowing. Some of these materials, in particular, monocrystalline ones, which are highly chemically resistant, mechanically durable, and stable under radiation damage are promising for application in optical couplers, robotics and medicine. They might be used for a long time (from tens to hundreds years) in aggressive chemical media and space. Crystals with low content of radionuclides (less than 0.1 wt%) but intensive self-glowing are main subject of interest. Phosphate and silicate single crystals with zircon structure: xenotime, (Y,...)PO{sub 4} and zircon, (Zr,...)SiO{sub 4}, were doped with {sup 238}Pu, {sup 237}Np and non-radioactive elements: Eu{sup 3+}; In{sup 3+} and Tb{sup 3+}. The most intensive self-glowing was obtained for xenotime crystals doped with 0.1 wt% {sup 238}Pu and Eu; and for zircon crystals doped with 0.01 wt% {sup 238}Pu and coupled admixture of In and Tb.

  11. Two-dimensional, hybrid model of glow discharge in hollow cathode geometries

    Energy Technology Data Exchange (ETDEWEB)

    Fiala, A.; Pitchford, L.C.; Boeuf, J.P. [Universite Paul Sabatier, Toulouse (France)

    1995-12-31

    Low pressure glow discharges in plane-plane geometries have been studied extensively over the years and most of their features are known from experiments and numerical simulation. If a plane cathode is replaced by a cathode with some hollow structure, then, for a certain range of conditions, the negative glows of opposite (adjacent) cathode walls overlap and the discharge behaviour dramatically changes. The voltage is lower at a constant current and the current is even several orders of magnitude higher for a given voltage than for the plane cathode. At the same time, the intensity of the light emission from the discharge considerably increases. This effect is called the hollow cathode effect. There are several physical phenomena which could be responsible for the big efficiency of the hollow cathode discharges. The recent investigations based on the Monte Carlo simulation of the electron kinetics have shown that the trapping of energetic electrons in the hollow cathode cavity can explain the order of magnitude of the hollow cathode effect. The configuration of the discharge tube presented in fig. 1 is used here to study the behaviour of glow discharges in a hollow cathode means of numerical simulation.

  12. Methane Conversion to C2 Hydrocarbons by Abnormal Glow Discharge at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    Dai Wei; Yu Hui; Chen Qi; Yin Yongxiang; Dai Xiaoyan

    2005-01-01

    Methane conversion to C2 hydrocarbons has been investigated with the addition of hydrogen in a plasma reactor of abnormal glow discharge at atmospheric pressure. The aim of this experiment is to minimize coke formation and improve discharge stability. The typical conditions in the experiment are 300 ml of total feed flux and 400 W of discharge power. The experimental results show that methane conversion is from 91.6% to 35.2% in mol, acetylene selectivity is from 90.2% to 57.6%, and ethylene selectivity is approximately from 7.8% to 3.6%,where the coke increases gradually along with the increase of CH4/H2 from 2: 8 to 9: 1. A stable discharge for a considerable running time can be obtained only at a lower ratio of CH4/H2= 2:8 or 3: 7. These phenomena indicate that the coke deposition during methane conversion is obviously reduced by adding a large amount of hydrogen during an abnormal glow discharge.A qualitative interpretation is presented, namely, with abundant hydrogen, the possibility that hydrogen molecules are activated to hydrogen radicals is increased with the help of the abnormal glow discharge. These hydrogen radicals react with carbon radicals to form C2 hydrocarbon products. Therefore, the deposition of coke is restrained.

  13. 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

  14. Characterization of W Coating on Cu Substrate Prepared by Double-Glow Discharge%Characterization of W Coating on Cu Substrate Prepared by Double-Glow Discharge

    Institute of Scientific and Technical Information of China (English)

    张福斌; 王正铎; 陈强; 蔡惠平

    2012-01-01

    In this study, tungsten (W) was coated on a copper (Cu) substrate by using doubleglow discharge technique using a pure W panel as the target and argon (Ar) as the discharge and sputtering gas. The crystal structure of the W coating was examined by X-ray diffraction (XRD). Scanning electron microscopy (SEM) was performed with cross-section images to investigate the penetration depth of W into the Cu body. Additionally, the properties of wearability resistance, corrosion resistance and mechanical strength of the W coated Cu matrix were also measured. It is concluded that in double-glow plasma, W coated Cu can be facilely prepared. It is noticed that the treatment temperature heavily dominates the properties of the W-Cu composite.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Synthesis and TL glow curve analysis of BaSO{sub 4}:Eu,Dy phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Rangeela Devi, Y. [Department of Physics, Manipur University, Canchipur, Imphal 795003 (India); Pachhunga University College, Aizawl, Mizoram (India); Dorendrajit Singh, S., E-mail: dorendrajit@yahoo.co.in [Department of Physics, Manipur University, Canchipur, Imphal 795003 (India)

    2012-06-15

    The polycrystalline samples of Ba{sub 1-x-y}SO{sub 4}:Eu{sub x},Dy{sub y} (0{<=}x{<=}1, 0{<=}y{<=}1) have been prepared using the chemical co-precipitation technique. The thermoluminescence (TL) sensitivity of the samples have been found changing with the value of x and y and the highest TL intensity is for Ba{sub 96}SO{sub 4}:Eu{sub 02},Dy{sub 02}. The sample has been characterised by x-ray diffraction (XRD). The samples are found to have orthorhombic structure. For TL analysis Ba{sub 96}SO{sub 4}:Eu{sub 02},Dy{sub 02} is annealed at different temperatures ranging from 873 to 1173 K. Kinetic parameters of all the TL glow curves of Ba{sub 1-x-y}SO{sub 4}:Eu{sub x},Dy{sub y} for different values of x and y and also for the TL glow curves Ba{sub 96}SO{sub 4}:Eu{sub 02},Dy{sub 02} annealed at different temperatures have been found out using computerised glow curve deconvolution (CGCD) method. The activation energy for the most intense TL peak at (444-453 K) is found out to be 1.26 eV and order of kinetics is 1.35. - Highlights: Black-Right-Pointing-Pointer TL study of BaSO{sub 4}:Eu,Dy is reported for the first time. Black-Right-Pointing-Pointer The kinetic parameters are evaluated by CGCD. Black-Right-Pointing-Pointer Effect of concentration, annealing temperature and dose response curve discussed.

  20. Degradation of Chloroanilines in Aqueous Solution by Contact Glow Discharge Electrolysis

    Institute of Scientific and Technical Information of China (English)

    高锦章; 胡中爱; 陆泉芳; 纳鹏君; 陈平; 刘永军; 俞洁

    2003-01-01

    Contact glow discharge electrolysis of some chloroanilines in sodium sulfate was investigated in different initial concentrations. Each of them underwent the dechlorination, deamination through oxidative degradation, and were eventually decomposed into hydrogen carbonate and carbon dioxide. It was testified that the chlorine atom and amidogen could be transformed into chloride ion and nitrite ion, respectively. Fe2+ has a remarkable catalytic effect on the degradation of them. On the basis of the detailed analysis of the intermediate products and kinetic behaviors, the reaction pathway was proposed, in which the attack of hydroxyl radical on the benzene ring of starting material might be a key step.

  1. Formation and dynamics of nano-particles in a stratified spherical glow discharge

    Science.gov (United States)

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

    2015-04-01

    The formation of clouds of dust nano-particles in a spherical dc glow discharge in ethanol was observed. Nano-particles were formed in a process of coagulation of ethanol dissociation products in a plasma of gas discharge. During the process the particles were captured into clouds in the electric potential wells of the strong striations of a spherical discharge. Periodically, the cloud of nano-particles experienced some sudden instability (explosion), and started to move to the cathode at high velocity. It was proved that the velocity of the particle clouds was an exponentially decaying function of time as in the case of dissipative dust solitary waves.

  2. Relativistic feedback models of terrestrial gamma-ray flashes and gamma-ray glows

    Science.gov (United States)

    Dwyer, J. R.

    2015-12-01

    Relativistic feedback discharges, also known as dark lightning, are capable of explaining many of the observed properties of terrestrial gamma-ray flashes (TGFs) and gamma-ray glows, both created within thunderstorms. During relativistic feedback discharges, the generation of energetic electrons is self-sustained via the production of backward propagating positrons and back-scattered x-rays, resulting in very larges fluxes of energetic radiation. In addition, ionization produces large electric currents that generate LF/VLF radio emissions and eventually discharge the electric field, terminating the gamma-ray production. In this presentation, new relativistic feedback model results will be presented and compared to recent observations.

  3. 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.}

  4. Radial Evolution of the Atmospheric Pressure Glow Discharge in Helium Controlled by Dielectric Barrier

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yuan-Tao; WANG De-Zhen; WANG Yan-Hui; LIU Cheng-Sen

    2005-01-01

    @@ The radial evolution of atmospheric pressure glow discharge in helium is presented by numerical simulation. The calculations reveal the mechanism of two current peaks per half cycle. The first breakdown occurs firstly in the central region of the electrode, and then spreads to the edge, while the second breakdown ignites at the periphery firstly, and then propagates toward the discharge central region. The simulations indicate that radial electric fields and radial sheath play an important role in the evolution of the second peak. These results agree fundamentally with the experimental observations.

  5. Study of stability of dc glow discharges with the use of Comsol Multiphysics software

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, P G C; Benilov, M S; Faria, M J [Departamento de Fisica, Universidade da Madeira, Largo do Municipio, 9000 Funchal (Portugal)

    2011-10-19

    Stability of different axially symmetric modes of current transfer in dc glow discharges is investigated in the framework of the linear stability theory with the use of Comsol Multiphysics software. Conditions of current-controlled microdischarges in xenon are treated as an example. Both real and complex eigenvalues have been detected, meaning that perturbations can vary with time both monotonically and with oscillations. In general, results given by the linear stability theory confirm intuitive concepts developed in the literature and conform to the experiment. On the other hand, suggestions are provided for further experimental and theoretical work.

  6. Reduction of TiO2 with hydrogen cold plasma in DC pulsed glow discharge

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-wen; DING Wei-zhong; LU Xiong-gang; GUO Shu-qiang; XU Kuang-di

    2005-01-01

    The reduction of TiO2 to Ti2O3 with hydrogen cold plasma generated by a DC pulsed glow discharge was realized under 2 500 Pa at 1 233 K. Only a little of Ti10O19 and Ti9O17 was detected for using molecular hydrogen.Enhancement effects of hydrogen cold plasma on the reduction were discussed in terms of thermodynamic coupling,kinetics and plasma sheath. The exited hydrogen species are considered more effective reducing agents. It is instructive to reduce refractory oxides with plasma hydrogen at the reduced temperature.

  7. Analysis of green fluorescent protein bioluminescence in vivo and in vitro using a glow discharge

    Science.gov (United States)

    Hernández, L.; Mandujano, L. A.; Cuevas, J.; Reyes, P. G.; Osorio-González, D.

    2015-03-01

    The discovery of fluorescent proteins has been a revolution in cell biology and related sciences because of their many applications, mainly emphasizing their use as cellular markers. The green fluorescent protein (GFP) is one of the most used as it requires no cofactors to generate fluorescence and retains this property into any organism when it is expressed by recombinant DNA techniques, which is a great advantage. In this work, we analyze the emission spectra of recombinant green fluorescent protein in vivo and in vitro exposed to a glow discharge plasma of nitrogen in order to relate electron temperature to fluorescence intensity.

  8. 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

  9. Genetic effects of radio-frequency, atmospheric-pressure glow discharges with helium

    Science.gov (United States)

    Li, Guo; Li, He-Ping; Wang, Li-Yan; Wang, Sen; Zhao, Hong-Xin; Sun, Wen-Ting; Xing, Xin-Hui; Bao, Cheng-Yu

    2008-06-01

    Due to low gas temperatures and high densities of active species, atmospheric-pressure glow discharges (APGDs) would have potential applications in the fields of plasma-based sterilization, gene mutation, etc. In this letter, the genetic effects of helium radio-frequency APGD plasmas with the plasmid DNA and oligonucleotide as the treated biomaterials are presented. The experimental results show that it is the chemically active species, instead of heat, ultraviolet radiation, intense electric field, and/or charged particles, that break the double chains of the plasmid DNA. The genetic effects depend on the plasma operating parameters, e.g., power input, helium flow rate, processing distance, time, etc.

  10. Irregular-regular-irregular mixed mode oscillations in a glow discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Sabuj, E-mail: sabuj.ghosh@saha.ac.in; Shaw, Pankaj Kumar, E-mail: pankaj.shaw@saha.ac.in; Saha, Debajyoti, E-mail: debajyoti.saha@saha.ac.in; Janaki, M. S., E-mail: ms.janaki@saha.ac.in; Iyengar, A. N. Sekar, E-mail: ansekar.iyengar@saha.ac.in [Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata-700064 (India)

    2015-05-15

    Floating potential fluctuations of a glow discharge plasma are found to exhibit different kinds of mixed mode oscillations. Power spectrum analysis reveals that with change in the nature of the mixed mode oscillation (MMO), there occurs a transfer of power between the different harmonics and subharmonics. The variation in the chaoticity of different types of mmo was observed with the study of Lyapunov exponents. Estimates of correlation dimension and the Hurst exponent suggest that these MMOs are of low dimensional nature with an anti persistent character. Numerical modeling also reflects the experimentally found transitions between the different MMOs.

  11. 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 liqu

  12. 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

  13. Visualizing ignition and combustion of methanol mixtures in a diesel engine; Methanol funmu no glow chakka to nensho no kashika

    Energy Technology Data Exchange (ETDEWEB)

    Inomoto, Y.; Harada, T.; Kusaka, J.; Daisho, Y.; Kihara, R.; Saito, T. [Waseda University, Tokyo (Japan)

    1997-10-01

    A glow-assisted ignition system tends to suffer from poor ignitability and slow flame propagation at low load in a direct-injection diesel engine fueled with methanol. To investigate the ignition process and improve such disadvantages, methanol sprays, their ignition and flames were visualized at high pressures and temperatures using a modified two-stroke engine. The results show that parameters influencing ignition, the location of a glow-plug, swirl level, pressure and temperature are important. In addition, a full kinetics calculation was conducted to predict the delay of methanol mixture ignition by taking into account 39 chemical species and 157 elementary reactions. 3 refs., 9 figs.

  14. Experimental measurements of the hollow cathode DC glow discharge parameters in Ar and He plasmas

    Science.gov (United States)

    Omrani, M.; Amrollahi, R.; Iraji, D.

    2016-12-01

    In this article, we focus on some of the fundamental parameters of SS316L hollow cathode glow discharge. Four SS316L samples are placed at different locations on the cathode surface and the current passed through them is measured in Ar and He glow discharge plasmas. The wall current densities of Ar and He are in the range of 8-25 µA cm-2 and 8-35 µA cm-2, respectively. Results also show that with decreasing working pressure, the ion flux and current density distribution on the wall surface becomes more uniform. The ion flux of the Ar and He is in the range of 1013 to 1014 ~\\text{ion} \\text{c}{{\\text{m}}-2} . Total energy losses of Ar and He are measured at the pressure range of 1.4-5.5  ×  10-2 torr and 3.2-7.1  ×  10-1, respectively. In both Ar and He, total energy losses decreased with increasing pressure. The secondary electron emission coefficients of Ar and He, which are evaluated for the hallow cathode configuration, are about 0.42 and 0.26, respectively, and are higher in comparison with the plate cathode configuration.

  15. 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.

  16. Investigation of helium ion production in constricted direct current plasma ion source with layered-glows

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yuna [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Chung, Kyoung-Jae, E-mail: jkjlsh1@snu.ac.kr [Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Park, Yeong-Shin [Samsumg Electronics Co. Ltd., Gyeonggi 445-701 (Korea, Republic of); Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

    2014-02-15

    Generation of helium ions is experimentally investigated with a constricted direct current (DC) plasma ion source operated at layered-glow mode, in which electrons could be accelerated through multiple potential structures so as to generate helium ions including He{sup 2+} by successive ionization collisions in front of an extraction aperture. The helium discharge is sustained with the formation of a couple of stable layers and the plasma ball with high density is created near the extraction aperture at the operational pressure down to 0.6 Torr with concave cathodes. The ion beam current extracted with an extraction voltage of 5 kV is observed to be proportional to the discharge current and inversely proportional to the operating pressure, showing high current density of 130 mA/cm{sup 2} and power density of 0.52 mA/cm{sup 2}/W. He{sup 2+} ions, which were predicted to be able to exist due to multiple-layer potential structure, are not observed. Simple calculation on production of He{sup 2+} ions inside the plasma ball reveals that reduced operating pressure and increased cathode area will help to generate He{sup 2+} ions with the layered-glow DC discharge.

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

    Energy Technology Data Exchange (ETDEWEB)

    Campsie, P; Cunningham, L; Hendry, M; Hough, J; Reid, S; Rowan, S; Hammond, G D, E-mail: p.campsie@physics.gla.ac.uk [SUPA , Institute for Gravitational Research, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ (United Kingdom)

    2011-11-07

    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 {approx} 200 ppm, in TiO{sub 2}-doped Ta{sub 2}O{sub 5}/SiO{sub 2} multi-layer coated fused silica.

  18. An Experimental Study on Atmospheric Pressure Glow Discharge in Different Gases

    Institute of Scientific and Technical Information of China (English)

    刘鹏; 詹如娟; 等

    2002-01-01

    Usually,the electrical breakdown of dielectric barrier discharge(DBD) at atmospheric pressure leads to a filamentary non-homogeneous discharge,However,it is also possible to obtain a diffuse DBD in homogeneous form,called atmospheric pressure glow discharge(APGD).We obtained a uniform APGD in helium and in the mixture of argon with alcohol,and studied the electrical characteristics of helium APGD.It if found that the relationship between discharge current and source frequency is different depending on the difference in gas gap when the applied voltage is kept constant.The discharge current shows an increasing trend with the increased frequency when gas gap is 0.8cm ,but the discharge current tends to decrease with the increased frequency when the gas gap increases.The discharge current always increases with the increased applied voltage when the source frequency is kept constant.We also observed a glow-like discharge in nitrogen at atmospheric pressure.

  19. Thermoluminescence glow curve deconvolution functions by continued fractions for different orders of kinetics

    Science.gov (United States)

    Flores-Llamas, H.; Gutiérrez-Tapia, C.

    2013-03-01

    The shape of the peaks in thermoluminescence (TL) dosimetry can be represented by the so-called temperature integral. In this paper, we present a very efficient method, based on a continued fraction approach to the incomplete gamma function, intended to calculate the overall temperature integral which includes the frequency factor ∝ T a . The single glow-peak algorithm for linear and exponential heating rates is derived. In the first case, the method provides a good approximation with a maximum relative error of 1.1×10-5 within the 0.1≤E/kT≤90 range in the case of a=0. It is shown that, in general, the method is efficient, converges quickly and can be adopted in the numerical fitting of glow lines in order to obtain the parameters relevant to TL. The utility of this approach is exemplified by adjusting the standard lithium flouride doped with magnesium and titanium (LiF): Mg, Ti (TLD-100) using five and six thermoluminescent peaks, determining that peak 6 is present and observable in the analysed spectrum. Finally, methods such as asymptotic expansion of the temperature integral by the asymptotic series approximation, the convergent series approximation, the Lagrange continued fraction approximation and a new obtained continued fraction approximation are compared with the method proposed here in the case of linear heating.

  20. Operation Mode on Pulse Modulation in Atmospheric Radio Frequency Glow Discharges

    Science.gov (United States)

    Zhang, Jie; Guo, Ying; Huang, Xiaojiang; Zhang, Jing; Shi, Jianjun

    2016-10-01

    The discharge operation regime of pulse modulated atmospheric radio frequency (RF) glow discharge in helium is investigated on the duty cycle and frequency of modulation pulses. The characteristics of radio frequency discharge burst in terms of breakdown voltage, alpha(α)-gamma(γ) mode transition voltage and current are demonstrated by the discharge current voltage characteristics. The minimum breakdown voltage of RF discharge burst was obtained at the duty cycle of 20% and frequency of 400 kHz, respectively. The α-γ mode transition of RF discharge burst occurs at higher voltage and current by reducing the duty cycle and elevating the modulation frequency before the RF discharge burst evolving into the ignition phase, in which the RF discharge burst can operate stably in the γ mode. It proposes that the intensity and stability of RF discharge burst can be improved by manipulating the duty cycle and modulation frequency in pulse modulated atmospheric RF glow discharge. supported by National Natural Science Foundation of China (Nos. 11475043 and 11375042)

  1. A Study on Helium Glow Discharge Cleaning in the HL- 1M Tokamak

    Institute of Scientific and Technical Information of China (English)

    王志文; 严东海; 王恩耀

    2002-01-01

    Based on the principle of ion-bombarded reemission and sputtering desorption, the Glow Discharge Cleaning with helium (GDC(He)) is an effective method for controlling the recycle of H on the chamber wall, Carbon(C), Oxygen(O) impurity and improving the wall conditioning in HL-1M tokamak. It is characterized by simplicity without magnet and safety, compared with Taylor Discharge Cleaning (TDC), Alternating current glow discharge Cleaning (AC), Electron Cyclotron Resonance-Discharge Cleaning (ECR-DC). Compared with bake-out degassing, the wall has a higher degassing rate during GDC(He) and a lower impurity concentration in vacuum chambers after GDC(He). Cleaning patterns have been developed dominantly for de-oxidization, decarbonization and de-hydrogenization. The cleaning parameters for H recycle on the wall are also presented. This paper mainly describes the GDC system along with its parameters, breakdown voltage, volt-ampere characteristic, the range of operation safe and suitable cleaning patterns in the HL-1M tokamak, finally concluding with some suggestions on HL-2A GDC.

  2. 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.

  3. High-Energy Radiation from Thunderstorms with ADELE: TGFs, Steps, and Glows

    Science.gov (United States)

    Smith, David M.; Kelley, Nicole; Martinez-McKinney, Forest; Zhang, Zi Yan; Hazelton, Bryna; Grefenstette, Brian; Splitt, Michael; Lazarus, Steven; Ulrich, William; Levine, Steven; Dwyer, Joseph; Schaal, Meagan; Saleh, Ziad; Cramer, Eric; Rassoul, Hamid; Cummer, Steven; Lu, Gaopeng; Shao, Xuan-Min; Ho, Cheng; Blakeslee, Richard

    2011-01-01

    The biggest challenge in the study of high-energy processes in thunderstorms is getting a detector to the vicinity of the electrically active regions of a storm. The Airborne Detector for Energetic Lightning Emissions (ADELE) has been used to detect gamma rays from aircraft above storms and from a storm-chasing van on the ground. In August 2009, ADELE flew above Florida storms in a Gulfstream V jet, detecting the first terrestrial gamma-ray flash (TGF) seen from a plane and continuous glows of high-energy emission above thunderclouds. The presence of these glows suggests that a gradual process of relativistic runaway and feedback may help limit the total amount of charging in thunderstorms, in contrast to the traditional view that only lightning discharges compete with the charging process. The upper limits on TGF emission from intracloud and cloud-to-ground lightning from the ADELE flights demonstrated conclusively that a TGF of the sort seen from space is not associated with most lightning and not necessary to trigger it. In August 2010, observations from a van detected stepped-leader x-ray emission from at least four lightning strikes in ten days of operations. This mode of operation is therefore promising for future observations of the stepping process, although a more varied suite of instrumentation, in particular a flash-distance detector, would be useful. We will report on these results and on future possibilities for ADELE campaigns.

  4. Glow curves and the emission of flux grown BaFCl-Tb crystals

    Energy Technology Data Exchange (ETDEWEB)

    Somaiah, K.; Moinuddin, S.R.; Nambi, K.S.V.

    1987-09-01

    Flux-grown BaFCl crystals containing 0.5 mol % of terbium were irradiated at room temperature by ..gamma..-rays from a /sup 60/Co source and glow curves and thermoluminescence emission spectra recorded. In addition to glow peaks at 385 and 410/sup 0/ K, which are present for undoped BaFCl, peaks occur at 470, 505, 570 and 665/sup 0/ K. The low temperature peaks are attributed to two types of F centre at F(Cl-bar) and F(F-bar) anion vacancies and the additional peaks to the presence of the terbium impurity in the BaFCl lattice. The thermoluminescence spectra show five emission bands. Those at 420, 435, 490 and 545 nm are attributed to transitions between the 4 f excited levels. A 390 nm emission, previously attributed to radiative recombination centres in undoped BaFCl, may in the light of these results be seen to arise from background terbium impurity in the starting material.

  5. 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.

  6. Validation and benchmarking of two particle-in-cell codes for a glow discharge

    Science.gov (United States)

    Carlsson, Johan; Khrabrov, Alexander; Kaganovich, Igor; Sommerer, Timothy; Keating, David

    2017-01-01

    The two particle-in-cell codes EDIPIC and LSP are benchmarked and validated for a parallel-plate glow discharge in helium, in which the axial electric field had been carefully measured, primarily to investigate and improve the fidelity of their collision models. The scattering anisotropy of electron-impact ionization, as well as the value of the secondary-electron emission yield, are not well known in this case. The experimental uncertainty for the emission yield corresponds to a factor of two variation in the cathode current. If the emission yield is tuned to make the cathode current computed by each code match the experiment, the computed electric fields are in excellent agreement with each other, and within about 10% of the experimental value. The non-monotonic variation of the width of the cathode fall with the applied voltage seen in the experiment is reproduced by both codes. The electron temperature in the negative glow is within experimental error bars for both codes, but the density of slow trapped electrons is underestimated. A more detailed code comparison done for several synthetic cases of electron-beam injection into helium gas shows that the codes are in excellent agreement for ionization rate, as well as for elastic and excitation collisions with isotropic scattering pattern. The remaining significant discrepancies between the two codes are due to differences in their electron binary-collision models, and for anisotropic scattering due to elastic and excitation collisions.

  7. Numerical modeling of a glow discharge through a supersonic bow shock in air

    Science.gov (United States)

    Rassou, S.; Packan, D.; Elias, P.-Q.; Tholin, F.; Chemartin, L.; Labaune, J.

    2017-03-01

    The interaction between a glow discharge and the bow shock of a Mach 3 air flow around a truncated conical model with a central spike is modeled, and comparison is made with prior experimental results. The KRONOS workflow for plasma modeling in flow fields, which has recently been developed at ONERA, was used for the modeling. Based on the quasi-neutral approximation, it couples hypersonic and reactive flow fields with electron chemistry, including the effect of non-Maxwellian electron energy distribution function. The model used for the discharge involves 12 species and 82 reactions, including ionization, electronic and vibrational excitation, and attachment. The simulations reproduce the main features of the discharge observed experimentally well, in particular, the very recognizable topology of the discharge. It was found from the simulations that behind the bow shock, in the afterglow, the negative ion flow ensures the electrical conduction and the establishment of the glow discharge. The influence of kinetic rates on the voltage-current characteristics is discussed.

  8. Molecular basis for the blue bioluminescence of the Australian glow-worm Arachnocampa richardsae (Diptera: Keroplatidae).

    Science.gov (United States)

    Trowell, Stephen C; Dacres, Helen; Dumancic, Mira M; Leitch, Virginia; Rickards, Rodney W

    2016-09-16

    Bioluminescence is the emission of visible light by living organisms. Here we describe the isolation and characterisation of a cDNA encoding a MW ≈ 59,000 Da luciferase from the Australian glow-worm, Arachnocampa richardsae. The enzyme is a member of the acyl-CoA ligase superfamily and produces blue light on addition of D-luciferin. These results are contrary to earlier reports (Lee, J., Photochem Photobiol 24, 279-285 (1976), Viviani, V. R., Hastings, J. W. & Wilson, T., Photochem Photobiol 75, 22-27 (2002)), which suggested glow-worm luciferase has MW ≈ 36,000 Da and is unreactive with beetle luciferin. There are more than 2000 species of firefly, which all produce emissions from D-luciferin in the green to red regions of the electromagnetic spectrum. Although blue-emitting luciferases are known from marine organisms, they belong to different structural families and use a different substrate. The observation of blue emission from a D-luciferin-using enzyme is therefore unprecedented.

  9. Characterization of the large area plane-symmetric low-pressure DC glow discharge

    Science.gov (United States)

    Avtaeva, S.; Gorokhovsky, V.; Myers, S.; Robertson, S.; Shunko, E.; Zembower, Z.

    2016-10-01

    Electron density and temperature as well as nitrogen dissociation degree in the low-pressure (10-50 mTorr) large area plane-symmetric DC glow discharge in Ar-N2 mixtures are studied by probes and spectral methods. Electron density measured by a hairpin probe is in good agreement with that derived from the intensity ratio of the N2 2nd positive system bands IC , 1 - 3/IC , 0 - 2 and from the intensity ratio of argon ions and atom lines IArII/IArI, while Langmuir probe data provides slightly higher values of electron density. Electron density in the low-pressure DC glow discharge varies with the discharge conditions in the limits of 108-1010 cm- 3. The concept of electron temperature can be used in low-pressure glow discharges with reservations. The intensity ratio of (0-0) vibrational bands of N2 1st negative and 2nd positive systems I391.4/I337.1 exhibits the electron temperature of 1.5-2.5 eV when argon fraction in the mixture is higher than nitrogen fraction and this ratio quickly increases with nitrogen fraction up to 10 eV in pure nitrogen. The electron temperature calculated from Langmuir probe I-V characteristics assuming a Maxwellian EEDF, gives Te 0.3-0.4 eV. In-depth analysis of the EEDF using the second derivative of Langmuir probe I-V characteristics shows that in a low-pressure glow discharge the EEDF is non-Maxwellian. The EEDF has two populations of electrons: the main background non-Maxwellian population of ;cold; electrons with the mean electron energy of 0.3-0.4 eV and the small Maxwellian population of ;hot; electrons with the mean electron energy of 1.0-2.5 eV. Estimations show that with electron temperature lower than 1 eV the rate of the direct electron impact ionization of N2 is low and the main mechanism of N2 ionization becomes most likely Penning and associative ionization. In this case, assumptions of the intensity ratio IN2+ , 391/IN2 , 337 method are violated. In the glow discharge, N2 dissociation degree reaches about 7% with the argon

  10. The effects of moon illumination, moon angle, cloud cover, and sky glow on night vision goggle flight performance

    Science.gov (United States)

    Loro, Stephen Lee

    This study was designed to examine moon illumination, moon angle, cloud cover, sky glow, and Night Vision Goggle (NVG) flight performance to determine possible effects. The research was a causal-comparative design. The sample consisted of 194 Fort Rucker Initial Entry Rotary Wing NVG flight students being observed by 69 NVG Instructor Pilots. The students participated in NVG flight training from September 1992 through January 1993. Data were collected using a questionnaire. Observations were analyzed using a Kruskal-Wallis one-way analysis of variance and a Wilcox matched pairs signed-ranks test for difference. Correlations were analyzed using Pearson's r. The analyses results indicated that performance at high moon illumination levels is superior to zero moon illumination, and in most task maneuvers, superior to >0%--50% moon illumination. No differences were found in performance at moon illumination levels above 50%. Moon angle had no effect on night vision goggle flight performance. Cloud cover and sky glow have selective effects on different maneuvers. For most task maneuvers, cloud cover does not affect performance. Overcast cloud cover had a significant effect on seven of the 14 task maneuvers. Sky glow did not affect eight out of 14 task maneuvers at any level of sky glow.

  11. A study on the behaviour of TLD-100 glow peaks at extreme ambient temperatures in Riyadh, Saudi Arabia.

    Science.gov (United States)

    Al-Haj, Abdalla N; Lagarde, Charlie S

    2006-01-01

    In this study, the temperature-induced variations in the TLD-100 response and the modifications in its glow peaks are investigated in real environmental exposure conditions in Riyadh, Saudi Arabia, where ambient temperatures during summer reach >45 degrees C and with relative humidity of 8814 TLD cardholders were deployed as environmental dosemeters for a period of approximately 1 month for 12 consecutive months. One group was irradiated to 5 mGy 137Cs prior to deployment; another was irradiated to the same dose after deployment, while the last group was left unirradiated. Analysis of glow curves was done using commercially available glow curve deconvolution software (CGCD). Monthly variations in peak 3, 4 and 5 areas relative to the corresponding peak areas of a prompt glow curve are presented. Results of this study show good TL signal compensation between peaks 4 and 5 at all ambient temperatures encountered in this experiment, despite the observed individual variations experienced by each of these peaks. The sum of peak 4 and 5 areas is constant to within approximately 10%, for both pre- and post-irradiated dosemeters, during this 12-month cycle.

  12. Development and fundamental investigation of Laser Ablation Glow Discharge Time-Of-Flight Mass Spectrometry (LA-GD-TOFMS)

    Energy Technology Data Exchange (ETDEWEB)

    Tarik, Mohamed [ETH Zurich, D-CHAB, Laboratory of inorganic chemistry, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland); Lotito, Giovanni [ETH Zurich, D-CHAB, Laboratory of inorganic chemistry, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland); TOFWERK AG, Uttigenstr. 22, 3600 Thun (Switzerland); Whitby, James A. [TOFWERK AG, Uttigenstr. 22, 3600 Thun (Switzerland); Mechanics of Materials and Nanostructures Laboratory, Empa - Materials Science and Technology, Feuerwerkerstr. 39, 3602 Thun (Switzerland); Koch, Joachim [ETH Zurich, D-CHAB, Laboratory of inorganic chemistry, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland); Fuhrer, Katrin; Gonin, Marc [TOFWERK AG, Uttigenstr. 22, 3600 Thun (Switzerland); Michler, Johann [Mechanics of Materials and Nanostructures Laboratory, Empa - Materials Science and Technology, Feuerwerkerstr. 39, 3602 Thun (Switzerland); Bolli, Jean-Luc [Ecole d' ingenieurs de Geneve, 4 Prairie, 1202 Geneva (Switzerland); Guenther, Detlef [ETH Zurich, D-CHAB, Laboratory of inorganic chemistry, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland)], E-mail: guenther@inorg.chem.ethz.ch

    2009-03-15

    Glow Discharge (GD) spectroscopy is a well known and accepted technique for the bulk and surface composition analysis, while laser ablation (LA) provides analysis with high spatial-resolution analysis in LIBS (laser-induced breakdown spectroscopy) or when coupled to inductively coupled plasma spectrometry (ICP-OES or ICP-MS). This work concerns the construction of a Laser Ablation Glow Discharge Time-Of-Flight Mass Spectrometry (LA-GD-TOFMS) instrument to study the analytical capabilities resulting from the interaction of a laser-generated sample plume with a pulsed glow discharge. Two ablation configurations were studied in detail. In a first approach, the laser-generated plume was introduced directly into the GD, while the second approach generated the plume inside the GD. The ablated material was introduced at different times with respect to the discharge pulse in order to exploit the efficient ionization in the GD plasma. For both LA-GD configurations, direct ablation into the afterglow of the pulsed glow discharge leads to an ion signal enhancement of up to a factor of 7, as compared to the ablation process alone under the same experimental conditions. The LA-GD enhancement was found to occur exclusively in the GD afterglow, with a maximum ablation S/N occurring in a few hundred microseconds after the termination of the glow discharge. The duration of the enhanced signal is about two milliseconds. Both the laser pulse energy and the position of the ablation plume (with respect to the sampling orifice) were found to affect the amount of mass entering the afterglow region and consequently, the enhancement factor of ionization.

  13. Development and fundamental investigation of Laser Ablation Glow Discharge Time-Of-Flight Mass Spectrometry (LA-GD-TOFMS)

    Science.gov (United States)

    Tarik, Mohamed; Lotito, Giovanni; Whitby, James A.; Koch, Joachim; Fuhrer, Katrin; Gonin, Marc; Michler, Johann; Bolli, Jean-Luc; Günther, Detlef

    2009-03-01

    Glow Discharge (GD) spectroscopy is a well known and accepted technique for the bulk and surface composition analysis, while laser ablation (LA) provides analysis with high spatial-resolution analysis in LIBS (laser-induced breakdown spectroscopy) or when coupled to inductively coupled plasma spectrometry (ICP-OES or ICP-MS). This work concerns the construction of a Laser Ablation Glow Discharge Time-Of-Flight Mass Spectrometry (LA-GD-TOFMS) instrument to study the analytical capabilities resulting from the interaction of a laser-generated sample plume with a pulsed glow discharge. Two ablation configurations were studied in detail. In a first approach, the laser-generated plume was introduced directly into the GD, while the second approach generated the plume inside the GD. The ablated material was introduced at different times with respect to the discharge pulse in order to exploit the efficient ionization in the GD plasma. For both LA-GD configurations, direct ablation into the afterglow of the pulsed glow discharge leads to an ion signal enhancement of up to a factor of 7, as compared to the ablation process alone under the same experimental conditions. The LA-GD enhancement was found to occur exclusively in the GD afterglow, with a maximum ablation S/N occurring in a few hundred microseconds after the termination of the glow discharge. The duration of the enhanced signal is about two milliseconds. Both the laser pulse energy and the position of the ablation plume (with respect to the sampling orifice) were found to affect the amount of mass entering the afterglow region and consequently, the enhancement factor of ionization.

  14. Characteristics of Ozone Production by Using Atmospheric Surface Glow Barrier Discharge

    Directory of Open Access Journals (Sweden)

    Mudtorlep NISOA

    2009-06-01

    Full Text Available Ozone is a strong oxidizer that can kill bacteria and other micro-organisms very effectively. In the recent years, ozone has become very important for sterilization of water used in shrimp farming and treatment of wastewater from food industry. However, ozonisers available in the markets are very expensive and have low energy-efficiency. In this work, a highly-efficient and low-cost system that can produce high-concentrations of ozone gas and dissolved ozone in water has been developed. The system consists of a dried air unit, high-voltage rf power supply, ozoniser tubes and venturi injector. The tubes are designed and configured to convert oxygen gas to ozone gas by atmospheric surface glow barrier discharge.

  15. Degradation of Methyl Orange in Water by Contact Glow Discharge Electrolysis

    Institute of Scientific and Technical Information of China (English)

    GONG Jianying; CAI Weimin

    2007-01-01

    The degradation of methyl orange in a neutral phosphate buffer solution was investigated by means of contact glow discharge electrolysis (CGDE).The methyl oranges were degraded and eventually decomposed into inorganic carbon when CGDE was conducted under the applied DC voltage of 480 V and current of ca.80 mA.As the intermediate products,some phenolic compounds were detected as well as carboxylic acids.Experimental results showed that the oxidation process followed the first-order reaction law.Based on the analysis of the ultraviolet (UV) spectra of the solution and the intermediate products from High Pressure Liquid Chromatography-Mass Spectrum (HPLC-MS),the reaction pathway was proposed.The attack of hydroxyl radicals was considered to be a key step to start the whole oxidation process.

  16. Application of Glow Discharge Aes for Investigation of Metal Ions and Water in Biology and Medicine

    CERN Document Server

    Bregadze, Vasil G; Tsakadze, Ketevan J

    2007-01-01

    AES VHF inductively coupled plasmatron may be applied to wide range of studies. It enables rapid microanalysis of various solutions including biological objects and peripheral blood serum. In addition, it may be used for investigation of water desorption from solid bodies and for determination of energetic metal-macromolecule complexes. Study of hydration energy and hydration number by kinetic curves of water glow discharge atomic spectral analysis of hydrogen (GD EAS analysis of hydrogen) desorption from Na-DNA humidified fibers allowed to reveal that structural and conformational changes in activation energy of hydrated water molecules increases by 0.65kcal/Mole of water. The developed method of analysis of elements in solutions containing high concentrations of organic materials allows systematic study of practically healthy persons and reveals risk factors for several diseases. Microelemental content of blood serum fractions showed that amount of not bounded with ceruloplasmin copper was three times more ...

  17. Aqueous 4-nitrophenol decomposition and hydrogen peroxide formation induced by contact glow discharge electrolysis.

    Science.gov (United States)

    Liu, Yongjun; Wang, Degao; Sun, Bing; Zhu, Xiaomei

    2010-09-15

    Liquid-phase decomposition of 4-nitrophenol (4-NP) and formation of hydrogen peroxide (H(2)O(2)) induced by contact glow discharge electrolysis (CGDE) were investigated. Experimental results showed that the decays of 4-NP and total organic carbon (TOC) obeyed the first-order and pseudo-first-order reaction kinetics, respectively. The major intermediate products were 4-nitrocatechol, hydroquinone, benzoquinone, hydroxyhydroquinone, organic acids and nitrite ion. The final products were carbon dioxide and nitrate ion. The initial formation rate of H(2)O(2) decreased linearly with increasing initial concentration of 4-NP. Addition of iron ions, especially ferric ion, to the solution significantly enhanced the 4-NP removal due to the additional hydroxyl radical formation through Fenton's reaction. A reaction pathway is proposed based on the degradation kinetics and the distribution of intermediate products.

  18. Atmospheric pressure air direct current glow discharge ionization source for ion mobility spectrometry.

    Science.gov (United States)

    Dong, Can; Wang, Weiguo; Li, Haiyang

    2008-05-15

    A new atmospheric pressure air direct current glow discharge (DCGD) ionization source has been developed for ion mobility spectrometry (IMS) to overcome the regularity problems associated with the conventional (63)Ni source and the instability of the negative corona discharge. Its general electrical characteristics were experimentally investigated. By equipping it to IMS, a higher sensitivity was obtained compared to that of a (63)Ni source and corona discharge, and a linear dynamic range from 20 ppb to 20 ppm was obtained for m-xylene. Primary investigations showed that alkanes, such as pentane, which are nondetectable or insensitively detectable with (63)Ni-IMS, can be efficiently detected by DCGD-IMS and the detection limit of 10 ppb can be reached. The preliminary results have shown that the new DCGD ionization source has great potential applications in IMS, such as online monitoring of environment pollutants and halogenated compounds.

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

    Science.gov (United States)

    Bilik, N.; Greenberg, B. L.; Yang, J.; Aydil, E. S.; Kortshagen, U. R.

    2016-06-01

    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-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. Some properties of a microwave boosted glow discharge source using neon as the operating gas.

    Science.gov (United States)

    Leis, F; Steers, E B

    1996-07-01

    The use of neon as the operating gas for the analysis of aluminium samples with the microwave boosted glow discharge source has been studied. A new type of anode tube allowed the gas to enter the source near the sample surface so that more material was transported into the discharge. Erosion rates have been measured under conditions optimised for high line-to-background ratios and found to be lower than with argon (9 and 21 n/s, respectively). Despite the lower erosion rate the detection limits measured for a number of elements in aluminium are in the range 0.02-1 microg/g and comparable to those obtained with argon as the operating gas.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-02-15

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

  2. A study of the glow discharge characteristics of contact electrodes at atmospheric pressure in air

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenzheng, E-mail: wzhliu@bjtu.edu.cn; Sun, Guangliang, E-mail: 11121659@bjtu.edu.cn; Li, Chuanhui; Zhang, Rongrong [School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044 (China)

    2014-04-15

    Electric field distributions and discharge properties of rod-rod contact electrodes were studied under the condition of DBD for the steady generation of atmospheric pressure glow discharge plasma (APGD) in air. We found that under the effect of the initial electrons generated in a nanometer-scale gap, the rod-rod cross-contact electrodes yielded APGD plasma in air. Regarding the rod-rod cross-contact electrodes, increasing the working voltage expanded the strong electric field area of the gas gap so that both discharge area and discharge power increased, and the increase in the number of contact points kept the initial discharge voltage unchanged and caused an increase in the plasma discharge area and discharge power. A mesh-like structure of cross-contact electrodes was designed and used to generate more APGD plasma, suggesting high applicability.

  3. Surface alloying of Cu with Ti by double glow discharge process

    Institute of Scientific and Technical Information of China (English)

    袁庆龙; 池成忠; 苏永安; 徐重; 唐宾

    2004-01-01

    The surface of pure copper alloyed with Ti using double glow discharge process was investigated. The morphology, structure and forming mechanism of the Cu-Ti alloying layer were analyzed. The microhardness and wear resistance of the Cu-Ti alloying layer were measured, and compared with those of pure copper. The results indicate that the surface of copper activated by Ar and Ti ions bombardment is favorable to absorption and diffusion of Ti element. In current experimental temperature, as the Ti content increases, the liquid phase occurs between the deposited layer and diffused layer, which makes the Ti ions and atoms easy to dissolve and the thickness of Cu-Ti alloying layer increase rapidly. After cooling, the structure of the alloying layer is composed of CuTi, Cu4 Ti and Cu(Ti) solid solution. The solid solution strengthening and precipitation strengthening effects of Ti result in high surface hardness and wear resistance.

  4. Modelling cathode spots in glow discharges in the cathode boundary layer geometry

    CERN Document Server

    Almeida, P G C; Bieniek, M S

    2015-01-01

    Self-organized patterns of cathode spots in glow discharges are computed in the cathode boundary layer geometry, which is the one employed in most of the experiments reported in the literature. The model comprises conservation and transport equations of electrons and a single ion species, written in the drift-diffusion and local-field approximations, and Poisson's equation. Multiple solutions existing for the same value of the discharge current and describing modes with different configurations of cathode spots are computed by means of a stationary solver. The computed solutions are compared to their counterparts for plane-parallel electrodes, and experiments. All of the computed spot patterns have been observed in the experiment.

  5. Characteristics of atmospheric-pressure, radio-frequency glow discharges operated with argon added ethanol

    Science.gov (United States)

    Sun, Wen-Ting; Li, Guo; Li, He-Ping; Bao, Cheng-Yu; Wang, Hua-Bo; Zeng, Shi; Gao, Xing; Luo, Hui-Ying

    2007-06-01

    Rf, atmospheric-pressure glow discharge (APGD) plasmas with bare metal electrodes have promising prospects in the fields of plasma-aided etching, thin film deposition, disinfection and sterilization, etc. In this paper, the discharge characteristics are presented for the rf APGD plasmas generated with pure argon or argon-ethanol mixture as the plasma-forming gas and using water-cooled, bare copper electrodes. The experimental results show that the breakdown voltage can be reduced significantly when a small amount of ethanol is added into argon, probably due to the fact that the Penning ionization process is involved, and a pure α-mode discharge can be produced more easily with the help of ethanol. The uniformity of the rf APGDs of pure argon or argon-ethanol mixtures using bare metallic electrodes is identified with the aid of the intensified charge coupled device images.

  6. Double Glow Plasma Surface Alloying Process Modeling Using Artificial Neural Networks

    Institute of Scientific and Technical Information of China (English)

    Jiang XU; Xishan XIE; Zhong XU

    2003-01-01

    A model is developed for predicting the correlation between processing parameters and the technical target of double glowby applying artificial neural network (ANN). The input parameters of the neural network (NN) are source voltage, workpiecevoltage, working pressure and distance between source electrode and workpiece. The output of the NN model is three importanttechnical targets, namely the gross element content, the thickness of surface alloying layer and the absorption rate (the ratioof the mass loss of source materials to the increasing mass of workpiece) in the processing of double glow plasma surfacealloying. The processing parameters and technical target are then used as a training set for an artificial neural network. Themodel is based on multiplayer feedforward neural network. A very good performance of the neural network is achieved and thecalculated results are in good agreement with the experimental ones.

  7. Photoelectronic properties of hydrogenated amorphous silicon films deposited by R. F sputtering and glow discharge methods

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Rahman, M.; Madkour, H. (Faculty of Science, Aswan (Egypt)); Hassan, H.H.; El-Desouki, S. (Cairo Univ., Giza (Egypt))

    1989-09-01

    Hydrogenated amorphous silicon films a-Si:H were deposited by both R.F. sputtering in a planar magnetron configuration and glow discharge methods on Corning glass substrates at different substrate temperatures. The dc and ac photoconductivities of the deposited films were extensively studied as a function of temperature, photon energy and photo-excitation intensity. The results showed that, the dark and photoconductivities have different dependency regions on temperature with different activation energies in the range of 0.08-0.20 eV. It has been also found that the photoconductivity is influenced by the method of deposition and the deposition parameters, indicating that the density of gap states is sensitive to the deposition conditions. The photoconductivity ({sigma}{sub ph}) has a power dependence on the illumination intensity (I) of the form {sigma}{sub ph} {alpha} I {sup {nu}}, where {nu} is a constant and was found also to be increase with temperature.

  8. Inactivation of Escherichia Coli Using Remote Low Temperature Glow Discharge Plasma

    Institute of Scientific and Technical Information of China (English)

    HU Miao; CHEN Jierong; CHEN Chua

    2008-01-01

    Low-temperature plasma is distinguished as a developing approach for sterilization which can deal with and overcome those problems such as thermal sensitivity and destruction by heat,formation of toxic by-products,higher costs and inefficiency in performances,caused by conventional methods.In this study,an experimental investigation was undertaken to characterize the effects of the operational parameters,such as treating time,discharge power and gas flow rate,of remote glow discharge air plasma.The results show that the inactivation of Escherichia coli can reach above 99.99% in less than 60 seconds and the optimal operational conditions for treating time,discharge power and gas flow rate were:40 s,80 W and 60 cm3/min,respectively.The contribution of UV radiation during plasma germ deactivation is very limited.

  9. Multi-element and isotopic analyses of iron meteorites using a glow discharge mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Shimamura, Tadashi (Kitasato Univ., Sagamihara (Japan). School of Hygienic Sciences); Takahashi, Takako (Marubun Corp., Kotoku, Tokyo (Japan). Analytical Research Lab.); Honda, Masatake; Nagai, Hisao (Nihon Univ., Tokyo (Japan). Coll. of Humanities and Sciences)

    1993-04-01

    Multi-element and isotopic analyses were performed of eight iron meteorites using a glow discharge mass spectrometer. Virtually all the elements can be determined. Major components (Fe, Co and Ni) through to ultra-trace constituents at the sub ng g[sup -1] level (Sc etc.) are measured directly with minimum chemical treatment within the same analytical cycle. Extremely high relative concentrations of Ni, Cu, Pd, In, Sn, Sb, Te, Pb and Bi were found in the meteorite Yamato 791694; the concentration of C was also very high. The isotopic composition of Pb in this meteorite was close to primordial. Low concentrations of C, N and O were found in the meteorite Gibeon. Very low S and Zn and high Cr and V were found in a third meteorite, Chinga. An excess of [sup 53]Cr was observed in Yamato 75031, which was consistent with the cosmic ray production level expected from the concentration of [sup 45]Sc. (Author).

  10. Glow discharge optical emission spectroscopy: a complementary technique to analyze thin electrodeposited polyaniline films

    Energy Technology Data Exchange (ETDEWEB)

    Moutarlier, V. [Institut UTINAM, CNRS-UMR 6213, Université de Franche-Comté, 16 route de Gray, 25030 Besançon (France); Lakard, S., E-mail: sophie.lakard@univ-fcomte.fr [Institut UTINAM, CNRS-UMR 6213, Université de Franche-Comté, 16 route de Gray, 25030 Besançon (France); Patois, T. [Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Croix du Sud, 1/4, 1348 Louvain-la-Neuve (Belgium); Lakard, B. [Institut UTINAM, CNRS-UMR 6213, Université de Franche-Comté, 16 route de Gray, 25030 Besançon (France)

    2014-01-01

    Glow Discharge Optical Emission Spectroscopy (GDOES) has been developed to perform depth profiles of thick metallic films, in tens of microns range. GDOES spectroscopy can also be used to analyze thin organic polymer films since this technique has a great potential thanks to its high depth resolution, multi-element capability, sensitivity, and adaptability to solids or films and to conducting or non-conducting samples. In particular thin electrodeposited conducting polymer films remain an unexplored field of investigation for GDOES technique. However GDOES was used in this work to analyze electrodeposited polyaniline films, in addition to other techniques such as profilometry, electron microscopy and X-ray diffraction (XRD). More precisely polyaniline thin films were electrodeposited from HCl solutions and the presence of an anilinium chloride excess at the top surface of the polymer film was demonstrated using GDOES and XRD. Rinsing of these films with water led to the removal of this excess and to the partial dedoping of the polymer film due to the porous structure of polymer films. Polyaniline thin films were also electrodeposited from H{sub 2}SO{sub 4} solutions and an anilinium hydrogen sulfate was similarly observed at the top surface of the polymer. This excess was removed by rinsing, contrary to hydrogen sulfate anions incorporated into the polymer film during the electrochemical polymerization that were not completely expulsed from the polyaniline films as proved using GDOES. - Highlights: • Polyaniline films were electrodeposited from HCl and H{sub 2}SO{sub 4} solutions • Polymer films were analyzed by Glow Discharge Optical Emission Spectroscopy (GDOES) • The incorporation of anions in the films was proved using GDOES depth profiles • The crystalline structure of polyaniline films was modified by water rinsing.

  11. Low-pressure glow discharge in a Xenon/Chlorine mixture

    Science.gov (United States)

    Shuaibov, A. K.; Shimon, L. L.; Shevera, I. V.; Dashchenko, A. I.

    2002-12-01

    The spatial, electrical, and optical characteristics of a transverse glow discharge and a volume discharge with a spherical anode and plane cathode in low-pressure Xe/Cl2 mixtures are studied. It is shown that the transverse glow discharge in mixtures with a low chlorine content occupies most of the interelectrode gap and exists in the form of strata. As the total pressure ( P≥300 Pa) and the partial chlorine pressure ( P(Cl2)≥80 Pa) increase, a solitary plasma domain with a volume of 1-2 cm3 forms in the discharge gap. It acts as a selective source of UV radiation in the XeCl(D-X) 236-nm, Cl2 (D'-A') 257-nm, and XeCl(B-X) 308-nm bands. In certain Xe/Cl2 mixtures, plasma self-oscillations in the frequency range 1-100 kHz are observed. The current of a low-pressure volume discharge with a spherical anode and plane cathode and the emission from it have both a dc and an ac component. The pressure and composition of the working mixture, as well as the average current of the volume discharge are optimized to attain the maximum emission intensity of the XeCl(D,B-X) bands. Low-pressure volume discharges in xenon/chlorine mixtures can be used as active media in low-pressure large-aperture planar or cylindrical excimer-halogen lamps emitting modulated or repetitive pulsed UV radiation.

  12. NITROGEN POTENTIAL DURING ION NITRIDING PROCESS IN GLOW-DISCHARGE PLASMA

    Directory of Open Access Journals (Sweden)

    A. A. Kozlov

    2015-01-01

    Full Text Available The paper considers problems on regulation of phase composition of a nitrided layer during gas and ion nitriding process in a glow-discharge. It has been established that  available models for control of nitrided layer structure with the help of nitriding index (nitrogen potential can not be applied for nitriding process in the glow-discharge. Principal difference of the ion nitriding from the gas one is in the fact that chemically active nitrogen is formed in the discharge zone (cathode layer and its mass-transfer is carried out in the form of an active particle flow (ions, atoms, molecules which directed to the metal surface.Interrelation of chemical discharge activity with such characteristics of nitriding steel as nitrogen solubility in  α-solid solution and  coefficient diffusion during ion nitriding in low-discharge plasma. It has been shown that regulation of the nitride layer structure during ion nitriding is reached due to changes in nitrogen flow density in plasma. While supporting the flow at the level of nitrogen solubility in  one phase or another (α, γ′  it is possible to obtain the nitrided layer consisting only of α-solid solution or γ′-nitride layer and diffusion sub-layer. Moreover a specific range of nitrogen flow density values exists for every steel grade where it is possible to ensure a limiting nitrogen concentration in α-solid solution and the γ′-layer characterized by low diffusion  mobility is not formed on the surface.

  13. Ca2+ sparks and Ca2+ glows in superior cervical ganglion neurons

    Institute of Scientific and Technical Information of China (English)

    Li-jun YAO; Cai-hong WU; Jie LIU; Zhuan ZHOU; He-ping CHENG; Gang WANG; Kun-fu OU-YANG; Chao-liang WEI; Xian-hua WANG; Shi-rong WANG; Wei YAO; Hong-ping HUANG; Jian-hong LUO

    2006-01-01

    Aim: Ca2+ release from the endoplasmic reticulum (ER) is an integral component of neuronal Ca2+ signaling. The present study is to investigate properties of local Ca2+ release events in superior cervical ganglion (SCO) neurons. Methods: Primary cultured SCO neurons were prepared from neonatal rats (P3-P7). Low concentration of caffeine was used to induce Ca2+ release from the ER Ca2+ store, and intracellular Ca2+ was recorded by high-resolution line scan confocal imaging and the Ca2+ indicator Fluo-4. Results: Two populations of local Ca2+ release events with distinct temporal characteristics were evoked by 1.5 mmol/L caffeine near the surface membrane in the soma and the neurites of SCG neurons. Brief events similar to classic Ca2+ sparks lasted a few hundreds of milliseconds, whereas long-lasting events displayed duration up to tens of seconds. Typical somatic and neurite sparks were of 0.3- and 0.52-fold increase in local Fluo-4 fluorescence, respectively. Typical Ca2+ glows were brighter (△F/F0 approximately 0.6), but were highly confined in space. The half maximum of full duration of neurite sparks was much longer than those in the soma (685 vs 381 ms). Conclusion: Co-existence of Ca2+ sparks and Ca2+ glows in SCG neurons indicates distinctive local regulation of Ca2+ release kinetics. The local Ca2+ signals of variable, site-specific temporal length may bear important implications in encoding a "memory" of the trigger signal.

  14. The Key Factor for Uniform and Patterned Glow Dielectric Barrier Discharge

    Institute of Scientific and Technical Information of China (English)

    OUYANG Ji-Ting; DUAN Xiao-Xi; XU Shao-Wei; HE Feng

    2012-01-01

    We present the results from 2D fluid modeling of the key roles controlling the glow dielectric barrier discharge (DBD) structure. A uniform DBD can be sustained at lower frequency when the space charge reaches uniformity due to plasma decay, while the patterned structure appears above a critical frequency when the space charge is nonuniform. The patterns start from the electrode edge where the electric field is significantly distorted, characterized by the patterned seed electrons that always form ahead of the surface charges. The formation of the patterned DBD structure is associated with the lateral inhibition of the local increase of space charges. The distribution of the volume seed electrons plays a key role in the DBD structure while the distribution of surface charge is a result of the formed structure.%We present the results from 2D fluid modeling of the key roles controlling the glow dielectric barrier discharge (DBD) structure.A uniform DBD can be sustained at lower frequency when the space charge reaches uniformity due to plasma decay,while the patterned structure appears above a critical frequency when the space charge is nonuniform.The patterns start from the electrode edge where the electric field is significantly distorted,characterized by the patterned seed electrons that always form ahead of the surface charges.The formation of the patterned DBD structure is associated with the lateral inhibition of the local increase of space charges.The distribution of the volume seed electrons plays a key role in the DBD structure while the distribution of surface charge is a result of the formed structure.

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

    Institute of Scientific and Technical Information of China (English)

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

    2012-01-01

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

  16. Study of the glow dynamics in a laser-produced plasma jet expanding across the magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Bessarab, A. V.; Bondarenko, G. A.; Garanin, S. G.; Zhidkov, N. V.; Nikitin, I. N.; Starodubtsev, V. A.; Sungatullin, R. R. [All-Russia Research Institute of Experimental Physics, Russian Federal Nuclear Center (Russian Federation)

    2011-09-15

    Results are presented from experimental studies of the glow dynamics of a plasma jet generated during the irradiation of a plane aluminum target by an iodine laser pulse with the wavelength 1.315 {mu}m. The laser pulse energy was 330-480 J, the pulse duration was 0.5 ns, and the focal spot diameter was 3 mm, the laser intensity on the target surface being {approx}10{sup 13} W/cm{sup 2}. The jet expanded across an external magnetic field with the strength {approx}1 kOe. The residual air pressure in the vacuum chamber was {approx}10{sup -5} Torr. The spatiotemporal behavior of the jet glow was investigated using a nine-frame camera in two mutually perpendicular directions (along and across the magnetic field). The results of measurements indicate azimuthal asymmetry of the jet expansion.

  17. XPS study of the corrosion resisting composite alloying layer obtained by double glow plasma with the brush plating Ni interlayer

    Institute of Scientific and Technical Information of China (English)

    Jiang Xu; Xishan Xie; Zhong Xu; Wenjin Liu

    2004-01-01

    The Ni-Cr-Mo-Cu multi-element surface alloying with the electric brush plating Ni interlayer on the low carbon steel substrate has been investigated. By the electrochemical method in 3.5% (mass fraction) NaC1 solution, the corrosion resistance of the composite alloying layer and single alloying layer is determined. The experimental results show that the corrosion resistance of the composite alloying layer is obviously better than that of the single alloying layer. The structure and composition of passive films formed on the two kinds of alloyed layers after electrochemical tests in 3.5% NaC1 solution have been studied using X-ray photoelectron spectroscopy (XPS). It is concluded that the double glow plasma surface alloying of low carbon steel with the electric brush plating Ni interlayer is an appropriate technique to enhance the corrosion resistance compared with the single double glow surface alloying.

  18. Analysis of read-out heating rate effects on the glow peaks of TLD-100 using WinGCF software

    Energy Technology Data Exchange (ETDEWEB)

    Bauk, Sabar, E-mail: sabar@usm.my [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Hussin, Siti Fatimah [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Alam, Md. Shah [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Physics Department, Shahjalal University of Science and Technology, Sylhet (Bangladesh)

    2016-01-22

    This study was done to analyze the effects of the read-out heating rate on the LiF:Mg,Ti (TLD-100) thermoluminescent dosimeters (TLD) glow peaks using WinGCF computer software. The TLDs were exposed to X-ray photons with a potential difference of 72 kVp and 200 mAs in air and were read-out using a Harshaw 3500 TLD reader. The TLDs were read-out using four read-out heating rates at 10, 7, 4 and 1 °C s{sup −1}. It was observed that lowering the heating rate could separate more glow peaks. The activation energy for peak 5 was found to be lower than that for peak 4. The peak maximum temperature and the integral value of the main peak decreased as the heating rate decreases.

  19. STUDY ON THE TANTALIZING ON THE SURFACE OF TITANIUM ALLOY BY NET-SHAPE CATHODE GLOW DISCHARGING

    Institute of Scientific and Technical Information of China (English)

    F. Chen; H. Zhou; Y.F. Zhang; J.D. Pan

    2005-01-01

    A new net-shape cathode sputtering target which has a simple structure and a high sputtering was put forward. The multiple-structure made of alloying and coating layers of tantalum was achieved on the surface of TC4 (Ti6Al4V) using this method in double glow surface alloying process. The tantalized samples were investigated by SEM, XRD and electrochemical corrosion method .Results show the complicated tissue of pure tantalizing layer and diffusion layer was successfully formed on the surface of TC4 with the method of net-shape cathode glow discharge, which further improved the corrosion-resistance of TC4 and formed good corrosion-resistant alloys.

  20. Plasma boronizing of Ti6AlV4 using solid precursors by double glow plasma alloying technique

    Institute of Scientific and Technical Information of China (English)

    QIN Lin; QU Jun-zhi; LIN Nai-ming; FAN Ai-lan; CHANG Da-qing; TANG Bin

    2006-01-01

    Solid state B-offerings (FeB compound) were used for plasma-assisted boronizing on Ti6Al4V alloy by double glow discharge plasma alloying technique (DGPSA). During all experiment processing there was no harmful and toxic. The thickness and morphology, phase formation, elements concentrations and wear properties of boride layers were examined by means of optical microscopy, Vickers microhardness, X-ray diffraction, glow discharge optical emission spectroscopy and Ball-disk wear tests. The results show that friction coefficient of boride alloying samples versus corundum ball is lower than that of Ti6Al4V samples, as well as wear rate. This indicates that plasma-assisted boronizing of Ti6Al4V alloy has a high potential for industrial applications under tribological conditions.

  1. On the increase in the limiting current of an atmospheric-pressure glow discharge in an argon flow

    Science.gov (United States)

    Baldanov, B. B.; Ranzhurov, Ts. V.

    2014-04-01

    The initiation of an atmospheric-pressure glow discharge (APGD) is studied in the multitip cathode-planar anode electrode system through which an argon flow passes. It is shown that sectioning of the cathode and ballast resistances present at corona tips make it possible to substantially expand the current region of the discharge and considerably raise the limiting current of the APGD. The shape of the coronafree electrode is found to influence the limiting discharge current.

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

    Science.gov (United States)

    Mashovets, N. S.; Pastukh, I. M.; Voloshko, S. M.

    2017-01-01

    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/cm2. 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. In addition, changing the technological mode allows you to manage a wide range of modified phase composition of the surface layer and as a result - to form the surface of titanium parts, taking into account the conditions of the subsequent operation.

  3. Sputtered-deposited thin brass films in a modified glow discharge Grimm-type source

    Science.gov (United States)

    Grais, K. I.; Eid, M. A.; Tawfik, N. L.; Abd-El-Aal, M. S.; Shaltout, A. A.

    2006-08-01

    Modification of the non-assisted gas flow-line across the target surface in a Grimm-type glow discharge source is described. The new flow line permits the gas to flow through a cylindrical annular space ending with a disc-space annular gap, facing the target surface. This configuration would cause directed jet assisted gas flow rays to impinge on infinite points across the cathode surface. Improvement has been achieved in the V-I characteristics where Δ V/Δ I increases from 1.8 to 3.5 V/mA. The sputtering as well as simultaneous deposition rates, have been increased by a factor of 16 and 17 respectively. These roll over with increasing sputtering time, their maximum values at a characteristic time, toc of 21 min. The toc value was constant for different operating parameters provided that the source geometry assembly is kept fixed. The presence of a glass substrate in the anode cavity has, apparently, no effect on the obtained data. Improvements have also been achieved in the crater profile, characterized by an approximately flat crater bottom with nearly vertical walls, and less re-deposited particles on the crater depth and edge. Fixing the distance Z of the substrate from target surface, along the cell axis, and varying the deposition time from 1 to 30 min, a sequence of changes in the deposited film were observed by X-ray diffraction and energy dispersion X-ray (EDX). These changes start with an amorphous structure, followed by the appearance of Cu and Zn crystallites and a probable deposition of Cu{5}Zn{8} clusters. The profile of the number of sputtered particles at different Z values is characterized by a number of peaks and troughs. This behavior has been explained by the occurrence of local cluster-dissociation and formation, by different collision processes. The improvements achieved by the application of the present jet assisted gas flow can be of value in the analytical application of this type of glow discharge.

  4. Effects of traces of molecular gases (hydrogen, nitrogen) in glow discharges in noble gases

    Science.gov (United States)

    Steers, E. B. M.; Smid, P.; Hoffmann, V.

    2008-07-01

    The "Grimm" type of low pressure glow discharge source, introduced some forty years ago, has proved to be a versatile analytical source. A flat sample is used as the cathode and placed about 0.2mm away from the end of a hollow tubular anode leading to an obstructed discharge. When the source was first developed, it was used for the direct analysis of solid metallic samples by optical emission spectroscopy (OES), normally with argon as the plasma gas; it was soon found that, using suitable electrical parameters, the cathode material was sputtered uniformly from a circular crater of diameter equal to that of the tubular anode, so that the technique could be used for compositional depth profile analysis (CDPA). Over the years the capability and applications of the technique have steadily increased. The use of rf powered discharges now permits the analysis of non-conducting layers and samples; improved instrumental design now allows CDPA of ever thinner layers (e.g. resolution of layers 5 nm thick in multilayer stacks is possible). For the original bulk material application, pre-sputtering could be used to remove any surface contamination but for CDPA, analysis must start immediately the discharge is ignited, so that any surface contamination can introduce molecular gases into the plasma gas and have significant analytical consequences, especially for very thin layers; in addition, many types of samples now analysed contain molecular gases as components (either as occluded gas, or e.g. as a nitride or oxide), and this gas enters the discharge when the sample is sputtered. It is therefore important to investigate the effect of such foreign gases on the discharge, in particular on the spectral intensities and hence the analytical results. The presentation will concentrate mainly on the effect of hydrogen in argon discharges, in the concentration range 0-2 % v/v but other gas mixtures (e.g. Ar/N_2, Ne/H_2) will be considered for comparison. In general, the introduction of

  5. DC negative corona discharge in atmospheric pressure helium: transition from the corona to the ‘normal’ glow regime

    Science.gov (United States)

    Hasan, Nusair; Antao, Dion S.; Farouk, Bakhtier

    2014-06-01

    Direct current (dc) negative corona discharges in atmospheric pressure helium are simulated via detailed numerical modeling. Simulations are conducted to characterize the discharges in atmospheric helium for a pin plate electrode configuration. A self-consistent two-dimensional hybrid model is developed to simulate the discharges and the model predictions are validated with experimental measurements. The discharge model considered consists of momentum and energy conservation equations for a multi-component (electrons, ions, excited species and neutrals) gas mixture, conservation equations for each component of the mixture and state relations. A drift-diffusion approximation for the electron and the ion fluxes is used. A model for the external circuit driving the discharge is also considered and solved along with the discharge model. Many of the key features of a negative corona discharge, namely non-linear current-voltage characteristics, spatially flat cathode current density and glow-like discharge in the high current regime are displayed in the predictions. A transition to the ‘normal’ glow discharge from the corona discharge regime is also observed. The transition is identified from the calculated current-voltage characteristic curve and is characterized by the radial growth of the negative glow and the engulfment of the cathode wire.

  6. Model Insensitive and Calibration Independent Method for Determination of the Downstream Neutral Hydrogen Density Through Ly-alpha Glow Observations

    Science.gov (United States)

    Gangopadhyay, P.; Judge, D. L.

    1996-01-01

    Our knowledge of the various heliospheric phenomena (location of the solar wind termination shock, heliopause configuration and very local interstellar medium parameters) is limited by uncertainties in the available heliospheric plasma models and by calibration uncertainties in the observing instruments. There is, thus, a strong motivation to develop model insensitive and calibration independent methods to reduce the uncertainties in the relevant heliospheric parameters. We have developed such a method to constrain the downstream neutral hydrogen density inside the heliospheric tail. In our approach we have taken advantage of the relative insensitivity of the downstream neutral hydrogen density profile to the specific plasma model adopted. We have also used the fact that the presence of an asymmetric neutral hydrogen cavity surrounding the sun, characteristic of all neutral densities models, results in a higher multiple scattering contribution to the observed glow in the downstream region than in the upstream region. This allows us to approximate the actual density profile with one which is spatially uniform for the purpose of calculating the downstream backscattered glow. Using different spatially constant density profiles, radiative transfer calculations are performed, and the radial dependence of the predicted glow is compared with the observed I/R dependence of Pioneer 10 UV data. Such a comparison bounds the large distance heliospheric neutral hydrogen density in the downstream direction to a value between 0.05 and 0.1/cc.

  7. 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.

  8. Simulation of radio-frequency atmospheric pressure glow discharge in γ mode

    Institute of Scientific and Technical Information of China (English)

    Shang Wan-Li; Wang De-Zhen; Michael G. Kong

    2007-01-01

    The existence of two different discharge modes has been verified in an rf (radio-frequency) atmospheric pressure glow discharge (APGD) by Shi [J. Appl. Phys. 97, 023306 (2005)]. In the first mode, referred to as α mode, the discharge current density is relatively low and the bulk plasma electrons acquire the energy due to the sheath expansion.In the second mode, termed γ mode, the discharge current density is relatively high, the secondary electrons emitted by cathode under ion bombardment in the cathode sheath region play an important role in sustaining the discharge. In this paper, a one-dimensional self-consistent fluid model for rf APGDs is used to simulate the discharge mechanisms in the γmode in helium discharge between two parallel metallic planar electrodes. The results show that as the applied voltage increases, the discharge current becomes greater and the plasma density correspondingly increases, consequentially the discharge transits from the c mode into the γ mode. The high collisionality of the APGD plasma results in significant drop of discharge potential across the sheath region, and the electron Joule heating and the electron collisional energy loss reach their maxima in the region. The validity of the simulation is checked with the available experimental and numerical data.

  9. Array of surface-confined glow discharges in atmospheric pressure helium: Modes and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Li, D.; Liu, D. X., E-mail: liudingxin@gmail.com, E-mail: mglin5g@gmail.com [Center for Plasma Biomedicine, State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Shaanxi (China); Nie, Q. Y.; Li, H. P. [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Chen, H. L. [Frank Reidy Center for Bioelectrics, Old Dominion University, Norfolk, Virginia 23508 (United States); Kong, M. G., E-mail: liudingxin@gmail.com, E-mail: mglin5g@gmail.com [Center for Plasma Biomedicine, State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Shaanxi (China); Frank Reidy Center for Bioelectrics, Old Dominion University, Norfolk, Virginia 23508 (United States); Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia 23529 (United States)

    2014-05-19

    Array of atmospheric pressure surface discharges confined by a two-dimensional hexagon electrode mesh is studied for its discharge modes and temporal evolution so as to a theoretical underpinning to their growing applications in medicine, aerodynamic control, and environmental remediation. Helium plasma surface-confined by one hexagon-shaped rim electrode is shown to evolve from a Townsend mode to a normal and abnormal glow mode, and its evolution develops from the rim electrodes as six individual microdischarges merging in the middle of the hexagon mesh element. Within one hexagon element, microdischarges remain largely static with the mesh electrode being the instantaneous cathode, but move towards the hexagon center when the electrode is the instantaneous anode. On the entire array electrode surface, plasma ignition is found to beat an unspecific hexagon element and then spreads to ignite surrounding hexagon elements. The spreading of microdischarges is in the form of an expanding circle at a speed of about 3 × 10{sup 4} m/s, and their quenching starts in the location of the initial plasma ignition. Plasma modes influence how input electrical power is used to generate and accelerate electrons and as such the reaction chemistry, whereas plasma dynamics are central to understand and control plasma instabilities. The present study provides an important aspect of plasma physics of the atmospheric surface-confined discharge array and a theoretical underpinning to its future technological innovation.

  10. Changes in the chemical reactivity of metals exposed to an inert gas glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Klemperer, D.F.; Williams, D.J. (Bristol Univ. (UK). Dept. of Physical Chemistry)

    1983-05-01

    From time to time the literature mentions curious effects on the chemical reactivity of metals due to inert gas ion bombardment: reactivity in corrosive environments is variously said to be inhibited or enhanced. Although there is no obvious explanation for such effects, some possible mechanisms have been suggested. Some simple experiments have been carried out to demonstrate that reactivity effects really do exist and to test such mechanisms. The results are qualitative because a glow discharge was used to implant the rare gas ions. Evaporated films of aluminium and nickel become amorphous after bombardment with xenon ions and the films resisted gaseous and liquid corrosion. On the other hand, aluminium foil bombarded with xenon ions in a Penning pump arrangement was attacked more heavily than unbombarded aluminium. Passivation is attributed to the known lack of reactivity of amorphous metals. Glassy materials appear to lack the normal routes of attack between their subsurface regions and the attacking medium. On the other hand, when a metal surface is heavily ion bombarded the surface is probably damaged to such an extent that the attacking medium gains physical access to the interior and corrosion proceeds rapidly.

  11. Photocatalytic Degradation of Methylene Blue with Side-glowing Optical Fiber Deliverying Visible Light

    Institute of Scientific and Technical Information of China (English)

    储金宇; 仲蕾

    2012-01-01

    The side-glowing optical fibers (SOFs) were chosen as the conducting medium of endogenous light; and 20 mg·L-1 methylene blue was chosen as the target to be degraded. The SOF is made up of quartz core with a silicon cladding, which can emit light through side surface more uniformly and transmit light for longer distance to avoid attenuation of light by liquid medium. The filament lamp was chosen as visible light source. Different reaction conditions, such as the presence of optical fiber or not, the quantity of SOF, light irradiation intensity were tested by measuring the methylene blue degradation of methylene blue. The results show that suitable reaction conditions were 1.167 g·L-1 Ag + /TiO 2 with 7% (by mass) of Ag + doped in TiO 2 , and 500 roots of SOF (30 cm length in solution). The photocatalytic degradation efficiency under 300W lamp irradiation for 8h was about 97%. And the photocatalytic degradation efficiency of methylene blue degradation was proportional to SOF quantity, light irradiation intensity and catalytic dosage within a certain range. Compared with general UV and visible light SOFs could save a huge amount of energy and cost, in the potential applications in dealing with organic pollutants on a large scale.

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

    Science.gov (United States)

    Zhang, Ling; He, Xiaoshan; Chen, Guo; Wang, Tao; Tang, Yongjian; He, Zhibing

    2016-03-01

    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 (T2B) 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.

  13. 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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2013-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kongpiboolkid, Watcharapon; Mongkolnavin, Rattachat [Department of Physics, Facuty of Science, Chulalongkorn University, Bangkok (Thailand); Plasma Technology and Nuclear Fusion Research Unit, Chulalongkorn University, Bangkok (Thailand)

    2015-04-24

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

  16. Liquid-phase reactions induced by atmospheric pressure glow discharge with liquid electrode

    Science.gov (United States)

    Tochikubo, Fumiyoshi; Shirai, Naoki; Uchida, Satoshi

    2014-12-01

    We experimentally investigated some of the initial reactions in a liquid induced by electron or positive-ion irradiation from an atmospheric-pressure dc glow discharge in contact with the liquid. We used an H-shaped glass reactor to observe the effects of electron irradiation and positive-ion irradiation on the liquid-phase reaction separately and simultaneously. Aqueous solutions of NaCl, AgNO3, HAuCl4, and FeCl2 are used as the electrolyte. Solutions of AgNO3 and HAuCl4 are used for the generation of Ag and Au nanoparticles, respectively. Solution of FeCl2 is used for the generation of ferromagnetic particles. Experimental results showed that electron irradiation of the liquid surface generates OH- in water and that positive-ion irradiation of the liquid surface generates H+ in water even without the dissolution of gas-phase nitrogen oxide. A possible reaction process is qualitatively discussed. We also showed that the control of reductive and oxidative environment in the liquid is possible not only by the gas composition for the plasma generation but also by the liquid composition.

  17. Surface Treatment of Polyethylene Terephthalate Film Using Atmospheric Pressure Glow Discharge in Air

    Institute of Scientific and Technical Information of China (English)

    方志; 邱毓昌; 王辉

    2004-01-01

    Non-thermal plasmas under atmospheric pressure are of great interest in polymer surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of Polyethylene terephthalate (PET) film surface for improving hydrophilicity using the non-thermal plasma generated by atmospheric pressure glow discharge (APGD) in air is conducted.The discharge characteristics of APGD are shown by measurement of their electrical discharge parameters and observation of light-emission phenomena, and the surface properties of PET before and after the APGD treatment are studied using contact angle measurement, x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It is found that the APGD is homogeneous and stable in the whole gas gap, which differs from the commonly filamentary dielectric barrier discharge (DBD). A short time (several seconds) APGD treatment can modify the surface characteristics of PET film markedly and uniformly. After 10 s APGD treatment, the surface oxygen content of PET surface increases to 39%, and the water contact angle decreases to 19°, respectively.

  18. 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.

  19. 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.

  20. Tribological Properties of the Fe-Al-Cr Alloyed Layer by Double Glow Plasma Surface Metallurgy

    Science.gov (United States)

    Luo, Xixi; Yao, Zhengjun; Zhang, Pingze; Zhou, Keyin; Wang, Zhangzhong

    2016-09-01

    A Fe-Al-Cr alloyed layer was deposited onto the surface of Q235 low-carbon steel via double glow plasma surface metallurgy (DGPSM) to improve the steel's wear resistance. After the DGPSM treatment, the Fe-Al-Cr alloyed layer grown on the Q235 low-carbon steel was homogeneous and compact and had a thickness of 25 µm. The layer was found to be metallurgically adhered to the substrate. The frictional coefficient and specific wear rate of the sample with a Fe-Al-Cr alloyed layer (treated sample) were both lower than those of the bare substrate (untreated sample) at the measured temperatures (25, 250 and 450 °C). The results indicated that the substrate and the alloyed layer suffered oxidative wear and abrasive wear, respectively, and that the treated samples exhibited much better tribological properties than did the substrate. The formation of Fe2AlCr, Fe3Al(Cr), FeAl(Cr), Fe(Cr) sosoloid and Cr23C6 phases in the alloyed layer dramatically enhanced the wear resistance of the treated sample. In addition, the alloyed layer's oxidation film exhibited a self-healing capacity with lubrication action that also contributed to the improvement of the wear resistance at high temperature. In particular, at 450 °C, the specific wear rate of treated sample was 2.524 × 10-4 mm3/N m, which was only 45.2% of the untreated sample.

  1. 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.

  2. Achieving ultrahigh vacuum in an unbaked chamber with glow discharge conditioning

    Indian Academy of Sciences (India)

    ZIAUDDIN KHAN; PRATIBHA SEMWAL; KALPESH R DHANANI; DILIP C RAVAL; SUBRATA PRADHAN

    2017-01-01

    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 which a detailed investigation has been carried out. Both helium and hydrogen gases have been employed as discharge cleaning medium. The discharge cleaning was carried out at 0.1 A/m$^{2}$ current density with workingpressure maintained at $1.0 \\times 10^{−2}$ mbar. It was experimentally observed that the pump-down time to attain the base pressure $∼10−8$ mbar was reduced by 62% compared to the unbaked chamber being pumped to this ultimate vacuum. The results were similar irrespective of whether the discharge cleaning medium is either hydrogen or helium. It was also experimentally established that a better ultimate vacuum could be achieved as compared to theoretically calculated ultimate vacuum with the help of discharge cleaning.

  3. Electric field development in γ-mode radiofrequency atmospheric pressure glow discharge in helium

    Science.gov (United States)

    Navrátil, Zdeněk; Josepson, Raavo; Cvetanović, Nikola; Obradović, Bratislav; Dvořák, Pavel

    2016-06-01

    Time development of electric field strength during radio-frequency sheath formation was measured using Stark polarization spectroscopy in a helium γ-mode radio-frequency (RF, 13.56 MHz) atmospheric pressure glow discharge at high current density (3 A cm-2). A method of time-correlated single photon counting was applied to record the temporal development of spectral profile of He I 492.2 nm line with a sub-nanosecond temporal resolution. By fitting the measured profile of the line with a combination of pseudo-Voigt profiles for forbidden (2 1P-4 1F) and allowed (2 1P-4 1D) helium lines, instantaneous electric fields up to 32 kV cm-1 were measured in the RF sheath. The measured electric field is in agreement with the spatially averaged value of 40 kV cm-1 estimated from homogeneous charge density RF sheath model. The observed rectangular waveform of the electric field time development is attributed to increased sheath conductivity by the strong electron avalanches occurring in the γ-mode sheath at high current densities.

  4. Abnormal glow discharge as a variable capacitor for tunable RF systems

    Science.gov (United States)

    Macheret, Sergey; Semnani, Abbas; Peroulis, Dimitrios

    2016-09-01

    For frequency-tunable resonators and filters in high-power applications, conventional semiconductor devices are easily damaged, while mechanically-tunable systems are bulky and slow. In this regard, weakly ionized plasmas can offer an attractive solution. In this work, an LC resonator circuit where a commercial gas discharge tube (GDT) serves as a variable capacitor was studied experimentally and theoretically. The experiments show continuous decrease of the resonant frequency by up to 50 percent with increase in the DC current through the GDT. Analysis of the current-voltage characteristic and the breakdown parameters, combined with lumped-parameter equivalent-circuit RF simulations, allowed us to determine the gas pressure, the electrode coating material and the secondary emission coefficient, and to achieve a very good agreement between the calculated and measured transmittance values. The analysis reveals that reduction in the cathode sheath thickness with increase in the DC current in the abnormal glow discharge regime is the key factor responsible for the experimentally observed tunability.

  5. Two-dimensional modeling of a glow discharge source for mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Fiala, A.; Pitchford, L.C.; Boeuf, J.P. [Univ. Paul Sabatier, Toulouse (France); Baude, S. [CEA, Bruyeres-le-Chatel (France); Blaise, G. [Univ. Paris 11, Orsay (France). Lab. de Physique des Solides

    1996-12-31

    Glow discharge mass spectrometry (GDMS) is now widely used for elemental analysis of various materials. This diagnostic uses a low current discharge in a buffer gas to sputter atoms from a sample to be analyzed. A small density of atoms of the sample are thus introduced into the gas phase. These atoms are ionized in the discharge, and the ions are extracted through a small, rectangular slit leading to a mass spectrometer. Very low absolute detection limits are possible with GDMS`s, but many aspects of this diagnostic still require careful adjustments to achieve good performance. A better understanding especially of the influence of the discharge operating conditions (pressure, current, geometry,...) on the ion fluxes arriving at the plane of the exit slit is needed. The purpose of the work presented here is to develop such an understanding through a combined experimental and theoretical program, but the work reported here relates mainly to results from the model. The particular conditions the authors have chosen to study correspond to the commercially available VG9000 spectrometer and Megacell source.

  6. The breakdown and glow phases during the initiation of discharges for lamps

    Energy Technology Data Exchange (ETDEWEB)

    Pitchford, L.C.; Peres, I.; Liland, K.B.; Boeuf, J.P. [Centre de Physique des Plasmas et Applications, Universite Paul Sabatier, 118 route de Narbonne, 31062 Toulouse (France); Gielen, H. [Central Development Laboratories, Philips Lighting, Eindhoven (The Netherlands)

    1997-07-01

    High intensity discharge (HID) lamps are often initiated by the application of one or more short, high-voltage, breakdown pulses superimposed on a 50 or 60 Hz generator voltage. A successful transition from the breakdown event to steady-state operating conditions in HID lamps requires that the lamp-circuit system be adequate to sustain the plasma created during breakdown until the electrodes are heated to thermionic temperatures. In this article, we use a one-dimensional (in the axial direction) transient discharge model to study the conditions needed to sustain the cold-cathode discharge after a breakdown event has occurred. While the application of our one-dimensional model to real lamps is approximate, we find that the model predictions are consistent with experimental results in HID lamps, a few of which are presented here. The main conclusion from this work is that, after breakdown, the voltage necessary to sustain a glow discharge is dependent on the source impedance, the gas composition, and on the plasma density created by the breakdown event. {copyright} {ital 1997 American Institute of Physics.}

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

    Science.gov (United States)

    Korolev, Yu. D.; Landl, N. V.; Geyman, V. G.; Frants, O. B.; Shemyakin, I. A.; Nekhoroshev, V. O.

    2016-08-01

    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.

  8. High frequency glow discharges at atmospheric pressure with micro-structured electrode arrays

    Science.gov (United States)

    Baars-Hibbe, L.; Sichler, P.; Schrader, C.; Lucas, N.; Gericke, K.-H.; Büttgenbach, S.

    2005-02-01

    Micro-structured electrode (MSE) arrays allow the generation of large-area uniform glow discharges over a wide pressure range up to atmospheric pressure. The electrode widths, thicknesses and distances in the micrometre range are realized by means of modern micro-machining and galvanic techniques. The electrode distance, the gap width d, is small enough to generate sufficiently high electric field strengths to ignite gas discharges by applying only moderate radio frequency (RF, 13.56 MHz) voltages (80-390 V in Ne, He, Ar, N2 and air). The non-thermal plasma system is characterized by a special probe measuring the electric parameters. We tested MSE arrays with d = 70, 25 and 15 µm. The MSE driven plasmas show a different behaviour from conventional RF discharge plasmas. Due to the very small electrode gap width we can describe the behaviour of the charged particles in the RF field of our system with the dc Townsend breakdown theory, depending on the pressure range and gas. With decreasing pressure, the gas discharges, especially in Ne and He, are increasingly dominated by field electron emission. With the MSE arrays as plasma sources several applications were developed and successfully tested, e.g. decomposition of waste gases and sterilization of food packaging materials at atmospheric pressure.

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

    Energy Technology Data Exchange (ETDEWEB)

    Minotti, F.; Giuliani, L.; Xaubet, M.; Grondona, D. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, C1428EHA, Buenos Aires, Argentina and Instituto de Física del Plasma (INFIP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires - UBA, C1428EHA, Buenos Aires (Argentina)

    2015-11-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Xu, S. F.; Zhong, X. X., E-mail: xxzhong@sjtu.edu.cn [The State Key Laboratory on Fiber Optic Local Area, Communication Networks and Advanced Optical Communication Systems, Key Laboratory for Laser Plasmas and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-10-15

    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.

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

    CERN Document Server

    Xu, Shaofeng

    2015-01-01

    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 simila...

  12. 灼热丝试验的设备确认方法及注意事项%The Verification Methods of Apparatus and Notes of the Glow-wire Test

    Institute of Scientific and Technical Information of China (English)

    陈向阳; 郭艳萍

    2015-01-01

    结合灼热丝试验装置和成品灼热丝可燃性试验方法标准要求,阐述灼热丝试验设备技术指标的确认方法,总结灼热丝试验中的注意事项.%This paper elaborates the verification methods of the glow wire test apparatus technical indicators, giving the notes of the glow wire test, while based on the standards of Glow-wire apparatus and the standard of Glow-wire flammability test method for end-products.

  13. Enhanced tissue integration of implantable electrodes for sensing, and stimulation, via radio frequency glow discharge

    Science.gov (United States)

    O'Connor, Laurie M.

    Biopotential electrodes are conductive materials that convert electronic currents to or from ionic currents for sensing, and stimulating specific tissue sites for medical applications. Implanted electrodes become "walled off" by the foreign body tissue reactions producing poorly attached scar capsules dominated by surrounding dense collagenous lamellae and source fibroblasts which are electrically resistive. The conductive interstitial fluid that is typical between an electrode and the resistive capsule allows spurious current paths. The insulating layer increases the distance between the electrode and the target sites and poor attachment often results in electrode migration within the host tissue. This investigation tested the hypothesis that surface-energy modulation of electrodes, via Radio Frequency Glow Discharge Treatment (RFGDT), can improve the performance of tissue-implantable electrodes by reducing the foreign body tissue reaction and enhancing interfacial bonding between the tissue and electrode material. Previously published findings were reproduced in a pilot study of explanted reference grade medical-grade methyl silicone (PDMS) and commercially pure titanium (cpTi) materials and their tissue capsules from 30-day subcutaneous exposures in Balb/C mice. The low-critical surface tension PDMS produced thick, dense, poorly attached scar capsules while the higher-surface-energy commercially pure titanium (cpTi) produced more cellular and strongly attached tissue layers difficult to delaminate from the biomaterial. For the main body of work, cpTi, capacitor-grade Tantalum (Ta), and synthetic heart valve-quality Pyrolytic Carbon (PyC) were evaluated, representative of potential high-surface-energy implant electrode materials. Their surface characteristics were determined as-manufactured and after Radio Frequency Glow Discharge Treatment (RFGDT) by Critical Surface Tension (CST) measurement, Scanning Electron Microscopy (SEM), Energy Dispersive X

  14. 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..

  15. Surface oxygen micropatterns on glow discharge polymer targets by photo irradiation

    Science.gov (United States)

    Reynolds, Hannah; Baxamusa, Salmaan; Haan, Steven W.; Fitzsimmons, Paul; Carlson, Lane; Farrell, Mike; Nikroo, Abbas; Watson, Brian J.

    2016-02-01

    Recent simulations predict surface oxygen may be a significant source of disruptive perturbations in the implosion process of glow-discharge polymers (GDP) ablators at the National Ignition Facility. GDP material held in ambient atmospheric conditions showed an increase in mass when stored in light transparent containers, which suggests that photo exposure is a driving force for oxygen absorption. To investigate if surface oxygen is a contributing factor of disruptive perturbations during implosion, a method to imprint a periodic micropattern of oxygen on the surface of GDP was developed and used to fabricate a flat sample for empirical testing. Photo exposure using collimated blue light was used to generate micropatterns of surface oxygen on the GDP material. The periodic oxygen micropattern was confirmed by secondary ion mass spectrometry (SIMS) and energy dispersive spectroscopy. A SIMS depth profile showed the atomic percent of oxygen ranged from 8 at. % near the surface to 1 at. % at a depth of 2 μm in a sample exposed for 4 min. The molecular interactions formed between the GDP and oxygen molecules were characterized using Fourier transform infrared resonance (FTIR), which showed the formation of hydroxyl (O-H) and carbonyl (C=O) bonds. The FTIR enabled the oxygen mass uptake as a function of photo exposure time to be quantified (resolved to typically 0.05 at. % oxygen). This experimental protocol was then applied to produce a GDP flat part with a periodic 75 μm wavelength micropattern of photo exposed (oxygen rich) and masked (oxygen deficient) regions. The micropatterned GDP ablators developed in this work are being used to assess the effect of surface oxygen on disruptive perturbations during the inertial confinement fusion implosion process.

  16. Conditioning of SST-1 Tokamak Vacuum Vessel by Baking and Glow Discharge Cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Ziauddin, E-mail: ziauddin@ipr.res.in; George, Siju; Semwal, Pratibha; Dhanani, Kalpeshkumar R.; Pathan, Firozkhan S.; Paravastu, Yuvakiran; Raval, Dilip C.; Babu, Gattu Ramesh; Khan, Mohammed Shoaib; Pradhan, Subrata

    2016-02-15

    Highlights: • SST-1 Tokamak was successfully commissioned. • Vacuum vessel was pumped down to 4.5 × 10{sup –8} mbar after baking and continuous GDC. • GDC reduced the water vapour by additional 57% while oxygen was reduced by 50%. • Under this condition, an initial plasma breakdown with current of 40 kA for 75 ms was achieved. - Abstract: Steady-state Superconducting Tokamak (SST-1) vacuum vessel (VV) adopts moderate baking at 110 ± 10 °C and the limiters baking at 250 ± 10 °C for ∼ 200 h followed by glow discharge cleaning in hydrogen (GDC-H) with 0.15 A/m{sup 2} current density towards its conditioning prior to plasma discharge experiment. The baking in SST-1 reduces the water (H{sub 2}O) vapor by 95% and oxygen (O{sub 2}) by 60% whereas the GDC reduces the water vapor by an additional 57% and oxygen by another 50% as measured with residual gas analyzer. The minimum breakdown voltage for H-GDC in SST-1 tokamak was experimentally observed to 300 V at 8 mbar cm. As a result of these adherences, SST-1 VV achieves an ultimate of 4.5 × 10{sup −8} mbar with two turbo-molecular pumps with effective pumping speed of 3250 l/s. In the last campaign, SST-1 has achieved successful plasma breakdown, impurity burn through and a plasma current of ∼ 40 kA for 75 ms.

  17. The influence of resonance radiation transport on the contraction of a glow discharge in argon

    Science.gov (United States)

    Golubovskii, Yu B.; Maiorov, V. A.

    2015-04-01

    The role of resonance radiation transport in the contraction of a positive column in an argon glow discharge is studied numerically. The theory is based on the self-consistent solution of the ambipolar diffusion equation for electrons, the diffusion equation for metastable atoms and the Biberman-Holstein equation for resonance atoms. To calculate the ionization and excitation rates, the Boltzmann equation is solved in a local approximation taking into account elastic, inelastic and electron-electron collisions. A solution method for a boundary problem is developed which allows one to obtain a hysteresis of the parameters during a continuous transition from a diffuse mode to a contracted mode through an unstable branch. At small currents there is a diffuse discharge where the role of radiation transport is inessential because the radial distributions of electrons and excited atoms are close to the fundamental modes of the corresponding equations. Under these conditions, the traditional approximation of ‘effective lifetime’ is accurate enough. For a contracted discharge, this approximation is not applicable because the higher diffusion and radiation modes play a notable role and a more strict description of radiation transport is required. It is shown that, when radiation transport is taken into account, the width of a filament in a contracted discharge significantly exceeds that obtained in the traditional ‘effective lifetime’ approximation. The critical current, when the discharge abruptly turns into a contracted mode, is shifted towards higher current values. The results obtained in this paper can also relate to a discharge in other inert gases.

  18. Signal Enhancement with Stacked Magnets for High-Resolution Radio Frequency Glow Discharge Mass Spectrometry.

    Science.gov (United States)

    Wei, Juan; Dong, Jiangli; Zhuo, Shangjun; Qian, Rong; Fang, Yuanxing; Chen, Qiao; Patel, Ekbal

    2017-01-17

    A method for signal enhancement utilizing stacked magnets was introduced into high-resolution radio frequency glow discharge-mass spectrometry (rf-GD-MS) for significantly improved analysis of inorganic materials. Compared to the block magnet, the stacked magnets method was able to achieve 50-59% signal enhancement for typical elements in Y2O3, BSO, and BTN samples. The results indicated that signal was enhanced as the increase of discharge pressure from 1.3 to 8.0 mPa, the increase of rf-power from 10 to 50 W with a frequency of 13.56 MHz, the decrease of sample thickness, and the increase of number of stacked magnets. The possible mechanism for the signal enhancement was further probed using the software "Mechanical APDL (ANSYS) 14.0". It was found that the distinct oscillated magnetic field distribution from the stacked magnets was responsible for signal enhancement, which could extend the movement trajectories of electrons and increase the collisions between the electrons and neutral particles to increase the ionization efficiency. Two NIST samples were used for the validation of the method, and the results suggested that relative errors were within 13% and detection limit for six transverse stacked magnets could reach as low as 0.0082 μg g(-1). Additionally, the stability of the method was also studied. RSD within 15% of the elements in three nonconducting samples could be obtained during the sputtering process. Together, the results showed that the signal enhancement method with stacked magnets could offer great promises in providing a sensitive, stable, and facile solution for analyzing the nonconducting materials.

  19. Role of cathode identity in liquid chromatography particle beam glow discharge mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, M.V. Balarama [Department of Chemistry, Biosystems Research Complex, Clemson University, Clemson, SC 29634-1905 (United States); Marcus, R.K. [Department of Chemistry, Biosystems Research Complex, Clemson University, Clemson, SC 29634-1905 (United States)], E-mail: marcusr@clemson.edu

    2008-06-15

    A detailed evaluation of the role of cathode identity on the analytical and spectral characteristics of various organic, organometallic and metal analytes using liquid chromatography-particle beam/glow discharge mass spectrometry (LC-PB/GDMS) has been carried out. A d.c. discharge, operating with argon as the support gas, was used throughout this work. In this study, Cu which has a relatively high sputtering rate, Ni which has moderate sputtering rate and Ta which has very low sputtering rate, are taken as cathode materials to study the ionization, fragmentation, and analytical characteristics of organic (caffeine, epigallocatechin gallate, peptide as representative compounds), organometallic (selenomethionine, triethyl lead chloride as representative compounds) and metal (Fe, La, Cs and Pb) species. A range of discharge gas pressures (26.6-106.4 Pa) and currents (0.2-1.5 mA) were investigated with the test cathodes to determine their influence on the spectral composition and overall analytical response for the various test species. Calibration plots were obtained for all of the species for each of the three cathodes to determine the respective limits of detection. Relative detection limits in the range of 0.02 to 15 ng mL{sup -1} (0.002-1.5 ng, absolute) for the test species were found to be in the order of Cu > Ni > Ta; which follows the order of the sputtering characteristics of the respective cathodes. These studies rendered information about the respective discharge parameters' role in choosing the most appropriate cathode identity in PB-GDMS for application in the areas of organic, organometallic and inorganic species analysis.

  20. Etching of UO{sub 2} in NF{sub 3} RF Plasma Glow Discharge

    Energy Technology Data Exchange (ETDEWEB)

    John M. Veilleux

    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 UO{sub 2} were conducted to demonstrate that plasma treatment is a viable method for decontaminating UO{sub 2} from stainless steel substrates. Experiments were conducted using NF{sub 3} gas to decontaminate depleted uranium dioxide from stainless-steel substrates. Depleted UO{sub 2} samples each containing 129.4 Bq were prepared from 100 microliter solutions of uranyl nitrate hexahydrate solution. The amorphous UO{sub 2} in the samples had a relatively low density of 4.8 gm/cm{sub 3}. Counting of the depleted UO{sub 2} 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, {sup 234}Th and {sup 234}Pa. 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 UO{sub 2} 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 UO{sub 2} in the samples was removed in just 17 minutes. The initial etch rate in the experiments ranged from 0.2 to 7.4 {micro}m/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 UO{sub 2} etching was also noted below 50 W in which etching increased up to a maximum pressure, {approximately}23 Pa, then decreased with further increases in pressure.

  1. 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.

  2. [Investigation on the Spectral Characteristics of a Plasma Jet in Atmospheric Argon Glow Discharge].

    Science.gov (United States)

    Li, Xue-chen; Zhang, Chun-yan; Li, Ji-yuan; Bao, Wen-ting

    2015-12-01

    Plasma jet is a kind of important plasma source at atmospheric pressure. In recent years, it becomes an important hot topic in the field of low temperature plasma. In this paper, using a tungsten needle and a tungsten wire mesh, a direct-current excited jet is developed to operate in argon at atmospheric pressure. In the atmospheric pressure argon, the plasma jet can produce a stable plasma plume. By using the method of emission spectroscopy, the parameters of the plasma plume are investigated. The discharge emits dazzling white light from the area between the tungsten needle electrode and the wire mesh electrode. A plasma plume with a flame shape appears outside the tungsten wire mesh electrode. For a constant value of voltage (U = 13.5 kV), the length of the plasma plume increases with the gas flow rate. For a constant value of the gas flow rate(10 L · min⁻¹), the length of the plasma plume increases with the voltage. The voltage is inversely proportional to the current under the constant gas flow rate. In other words, the voltage decreases with the discharge current, which indicates that a glow discharge is formed in the plasma jet. Optical emission spectrum in 300 to 800 nm is collected from the direct-current excited plasma jet. By Boltzmann plot method, the excited electron temperature of the plasma plume is investigated as a function of the applied voltage or the gas flow rate. Results show that the excited electron temperature increases with decreasing applied voltage under the constant gas flow. Moreover, it increases with decreasing the gas flow under the constant voltage. Based on the discharge theory, these experimental phenomena are explained qualitatively. These results are of great importance to the development of atmospheric pressure uniform discharge plasma source and its application in industrial field.

  3. 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

  4. Investigation of Meltblown Microfiber and Electrospun Nanofiber Fabrics Treated with a One Atmosphere Uniform Glow Discharge Plasma (OAUGDP)

    Science.gov (United States)

    Chen, Weiwei; Reece Roth, J.; Tsai, Peter P.-Y.

    2003-10-01

    Nanofiber webs are made by the electrospinning (ES) process [1], which uses the repulsive electrostatic force to spin fibers from a polymer solution or melt at room temperature and low energy input. We have developed apparatus at the UT Textiles and Nonwovens Development Center (TANDEC) to produce fabrics with fiber diameters of tens of nanometers. This paper will report data on the distribution function of nanofiber diameters that were taken from digitized SEM images of the electrospun materials. It is also found in the tensile tests that the strength of the electrospun nanofiber fabrics is up to ten times that of the coarser meltblown material. The one atmosphere uniform glow discharge plasma (OAUGDP) developed at the UT Plasma Sciences Laboratory generates a normal glow electrical discharge at one atmosphere. This plasma has been used to treat meltblown and electrospun fabrics, with a resulting increase in surface energy [1]. We recently found that the surface energy of meltblown Nylon could be increased to 70 dynes/cm by five seconds of OAUGDP exposure, and was durable at this level for six months. Our results also show that Nylon and PU nanofiber fabrics can be exposed to the OAUGDP for treatment without significant damage for up to 10 seconds [1], a duration sufficient to produce important effects, including durable wettability. We will describe our progress in improving the properties of nanofiber fabrics using a variety of latest developments in OAUGDP reactor technology, including a new porous electrode that injects gases other than air to generate different active species for plasma treatment. [1] Tsai P. P.-Y., Chen W., Li X. and Roth J.R.: "Improving the Properties of Protective Clothing by Exposing Nanofiber Webs to a One Atmospheric Uniform Glow Discharge Plasma (OAUGDP)", National Science Foundation (NSF) Grantee¡¯s Workshop and Conference, Birmingham, Alabama, Jan. 6-9, 2003.

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

    CERN Document Server

    Semenov, A P

    2001-01-01

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

  6. 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.

  7. 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.

  8. 辉光放电质谱仪Element GD的应用%Application of Newest Glow Discharge Mass Spectrometer- Element GD

    Institute of Scientific and Technical Information of China (English)

    尹松; 王勇为; 周昕; 蒋季春; 肖陈刚

    2005-01-01

    A newest high resolution glow discharge mass spectrometer (HR-GD-MS) was developed by Thermo Electron Bremen Manufactory. Combine of a glow discharge ion source with a successful high resolution mass spectrometer, Element GD become the ultimate tool for direct analysis of conductive materials. Every part of Element GD: GD ion source, mass spectrometer, detection system and software are designed for high throughput analysis: measure 50 elements at less than 10-9 within 5 minutes. Application in microelectronics, aerospace, medical/pharmaceutical/food and nuclear will be shown.

  9. Applicability of the Child-Langmuir laws versions for describing the glow discharge cathode sheath in CO2

    Science.gov (United States)

    Lisovskiy, Valeriy; Krol, Hennadii; Osmayev, Ruslan; Yegorenkov, Vladimir

    2016-09-01

    This work is devoted to the determination of the law that may be applicable to the description of the cathode sheath in CO2. To this end three versions of the Child-Langmuir law have been considered - a collision free one (for the ions moving through a cathode sheath without collisions with gas molecules) as well as two collision- related versions- one for a constant mean free path of positive ions and one for a constant mobility of positive ions. The current-voltage characteristics and the cathode sheath thickness of the glow discharge in carbon oxide have been simultaneously measured in the pressure range from 0.05 to 1 Torr and with the discharge current values up to 80 mA. The inter-electrode distance has been chosen such that the discharge consists only of the cathode sheath and a small portion of the negative glow, i.e. the experiments have been performed in short tubes. In this case the voltage drop across the cathode sheath is equal approximately to the voltage drop across the electrodes. In the whole range of the discharge conditions we have studied the cathode sheath characteristics are found to obey correctly only to the Child-Langmuir law version with a constant ion mobility. The reason for this phenomenon may be related with a significant conversion of carbon dioxide molecules.

  10. A Comparative Study between the Filamentary and Glow Modes of DBD Plasma in the Treatment of Wool Fibers

    Directory of Open Access Journals (Sweden)

    Doaa. M. El-Zeer

    2014-03-01

    Full Text Available In the present research it has been studied the effect of the DBD plasma on the treatment and modification of the surface a printing properities of the wool. Two types of DBD plasma have been investigated namely; the filamentary mode FDBD plasma and the glow mode GDBD plasma to reach the best condition of the treatment. Two discharge cells have been constructed one of them is for the generation of Atmospheric pressure glow discharge APGD and the other is for the generation of filamentary dielectric barrier discharge FDBD plasma. These two cells have the same dimensions except for the type of the dielectric barrier. In the APGD cell the dielectric barrier is a commercial porous fiber while in the FDBD cell the barrier is a Pyrex glass. It has been found that changing the type of the dielectric barriers acquires the discharge different properties. The efficiencies of these two types of discharge in the treatment of the textiles has been examined by treating the wool fabric with these two types of DBD plasma at different conditions of the current and treatment time. The induced changes in wool properties, such as whiteness index, wettability, tensile strength, elongation %, surface morphology, printability and fastness properties, have been investigated. The surface characterization was performed using FTIR and SEM imaging. It has been discovered that GDBD plasma is more efficient than FDBD because of not only its homogeneity but also the high concentration of nitrogen excited species that are the responsible for the surface activation of the textile.

  11. Pioneer 10 ultraviolet photometer observations of the interplanetary glow at heliocentric distances from 2 to 14 AU

    Science.gov (United States)

    Wu, F. M.; Judge, D. L.; Suzuki, K.; Carlson, R. W.

    1981-01-01

    An analysis is presented of the observed Pioneer 10 interplanetary data from 1972 to 1977, taking into account the interplanetary glow intensity observed by the Pioneer 10 UV photometer at sun-spacecraft distances of 2-14 AU. On the basis of the obtained data, it was determined that the background intensity for the 200-1400 A band pass of the photometer channel is about 40 + or - 10 R, and that the nearby interstellar density is 0.04 + or - 0.91 per ccm for hydrogen and about 0.01 + or - 0.002 per ccm for helium. Accordingly, the He/H number density is about 0.25 at large distances from the sun. The Pioneer 10 spacecraft is leaving the solar system in the downwind direction, while both Pioneer 11 and Voyager will leave in the upwind direction. The combined UV observations of the interplanetary glow will provide accurate results on the physical status of the inflowing interstellar gas and the variability of background radiation as well.

  12. Proton transfer mass spectrometry at 11 hPa with a circular glow discharge: Sensitivities and applications

    Science.gov (United States)

    Hanson, D. R.; Koppes, M.; Stoffers, A.; Harsdorf, R.; Edelen, K.

    2009-04-01

    The design and testing of a circular glow discharge ion source on a custom built proton transfer mass spectrometer are described. Also, issues important for quantitative measurements of volatile organic compounds using this instrument were investigated. Detailed calibration procedures based on gravimetry are presented, and representative outdoor air data are shown. Calibrations yield a good sensitivity, up to a few Hz/pptv for some compounds, and the detection limit (S/N = 3) is ~100 pptv or better for methanol, acetaldehyde and acetone (5 s sampling time with a 5 s zero). Detection limits are much lower for most other compounds due to high sensitivity and low background. For ions with m/z > ~90 the background signals are very low and species that appear efficiently at these m/z can be detected at the 10 pptv level in a few seconds. Ion breakup processes for alcohols show that a major product ion of mono-functional alcohols is at 57 u, presumably C4H9+. Oxalic acid is an interesting case in that a major product ion appears on an even mass, 46 u, presumably CO2H2+. The circular glow discharge source is easy to construct and deploy in proton transfer mass spectrometry studies at ~11 hPa. Continuous use of the system over time periods of many days and stable operation over time periods of months to years between disassembly and cleaning demonstrates its robustness.

  13. Characteristics in the jet region of helium radio-frequency atmospheric-pressure glow discharge with array generators

    Directory of Open Access Journals (Sweden)

    Zhi-Bin Wang

    2015-09-01

    Full Text Available The two-dimensional spatially extended atmospheric plasma arrays by many parallel radio-frequency glow discharge plasma jets packed densely, represent a feature option of large-scale low-temperature atmospheric plasma technologies with distinct capability of directed delivery of reactive species and good insusceptibility to sample variations. However, it is still a challenge to form plasma jet with large area of uniform active species on a downstream substrate due to the complex interactions between individual jets. This paper proposes to numerically study the strategy and mechanism of control/modulation for the array discharge to produce two-dimensional plasma uniformity in the downstream working area. In this work, a two dimensional fluid model is employed to investigate the characteristics in the jet region of helium radio-frequency atmospheric-pressure glow discharge (RF APGD with array generators. The influences of upstream discharge characteristics, gas flow and their cooperative effects on the distribution of species densities, gas temperatures and the uniformity of active species in the material treating area is studied, and the essential strategy for the modulation method is acquired. The results will be significant for deep understanding of coupling behaviors of multiple plasma plumes in the RF APGD array and applications of the technology.

  14. Performance and Emission Characteristics on Glow Plug Hot Surface Ignition C.I. Engine Using Methanol as Fuel With Additive

    Directory of Open Access Journals (Sweden)

    B.OMPRAKASH

    2015-07-01

    Full Text Available The concept of using alcohol fuels as alternative to diesel fuel in diesel engine is recent one. The scarcity of transportation petroleum fuels due to the fast depletion of the petroleum deposits and frequent rise in their costs in the international market have spurred many efforts to find alternatives. Alcohols were quickly recognized as prime candidates to displace or replace high octane petroleum fuels. Innovative thinking led to find varies techniques by which alcohol can be used as fuel in diesel engine. Amongst the fuel alternative proposed, the most favourest ones are methanol and ethanol. The specific tendency of alcohols to ignite easily from a hot surface makes it suitable to ignite in a diesel engine by different methods. The advantage of this property of alcohols enables to design and construct a new type of engine called surface ignition engine. Methanol and ethanol are very susceptible to surface ignition, this method is very suitable for these fuels. The hot surfaces which, can be used in surface ignition engine are electrically heated glow plug with hot surface. Hence present research work carries the experimental investigation on glow plug hot surface ignition engine, by adding different additives with methanol and ethanol as fuels, with an objective to find the best one performance, emission and compression parameters.

  15. 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

  16. Adsorption of HSA, IgG and laminin-1 on model titania surfaces--effects of glow discharge treatment on competitively adsorbed film composition.

    Science.gov (United States)

    Santos, Olga; Svendsen, Ida E; Lindh, Liselott; Arnebrant, Thomas

    2011-10-01

    This study investigated the effect of glow discharge treatment of titania surfaces on plasma protein adsorption, by means of ellipsometry and mechanically assisted SDS elution. The adsorption and film elution of three plasma proteins, viz. human serum albumin (HSA), human immunoglobulin G (IgG) and laminin-1, as well as competitive adsorption from a mixture of the three proteins, showed that the adsorbed amount of the individual proteins after 1 h increased in the order HSA glow discharge treated titania surfaces. However, the composition of the adsorbed films from the mixture differed between the untreated and glow discharge treated substrata. On glow discharge-treated titania the fraction of HSA increased, the fraction of laminin-1 decreased and the fraction of IgG was unchanged compared to the adsorption on the untreated titania, which was attributed to protein-protein interactions and competitive/associative adsorption behaviour.

  17. Final Report DE-FG02-00ER54583: "Physics of Atmospheric Pressure Glow Discharges" and "Nanoparticle Nucleation and Dynamics in Low-Pressure Plasmas"

    Energy Technology Data Exchange (ETDEWEB)

    Uwe Kortshagen; Joachim Heberlein; Steven L. Girshick

    2009-06-01

    This project was funded over two periods of three years each, with an additional year of no-cost extension. Research in the first funding period focused on the physics of uniform atmospheric pressure glow discharges, the second funding period was devoted to the study of the dynamics of nanometer-sized particles in plasmas.

  18. Using the computerized glow curve deconvolution method and the R package tgcd to determination of thermoluminescence kinetic parameters of chilli powder samples by GOK model and OTOR one

    Science.gov (United States)

    Sang, Nguyen Duy; Van Hung, Nguyen; Van Hung, Tran; Hien, Nguyen Quoc

    2017-03-01

    The kinetic parameters of thermoluminescence (TL) glow peaks of chilli powder irradiated by gamma rays with the different doses of 0, 4 and 8 kGy have been calculated and estimate by computerized glow curve deconvolution (CGCD) method and the R package tgcd by using the TL glow curve data. The kinetic parameters of TL glow peaks (i.e. activation energies (E), order of kinetics (b), trapping and recombination probability coefficients (R) and frequency factors (s)) are fitted by modeled general-orders of kinetics (GOK) and one trap-one recombination (OTOR). The kinetic parameters of the chilli powder are different toward the difference of the sample time-storage, radiation doses, GOK model and OTOR one. The samples spending the shorter period of storage time have the smaller the kinetic parameters values than the samples spending the longer period of storage. The results obtained as comparing the kinetic parameters values of the three samples show that the value of non-irradiated samples are lowest whereas the 4 kGy irradiated-samples' value are greater than the 8 kGy irradiated-samples' one time.

  19. Drift model of a glow discharge with account for the nonlocal value of the electric field strength in the ionization source

    Science.gov (United States)

    Saifutdinov, A. I.; Timerkaev, B. A.

    2012-09-01

    A drift model of a glow discharge is proposed, which takes account of the nonlocal dependence of the ionization source on the electric field strength. The problem is reduced to solving a nonlinear differential equation of second order for the strength squared using the Newton-Kantorovich quasilinearization method.

  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. 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.

  2. The role of oxygen in analytical glow discharges: GD-OES and GD-ToF-MS studies

    Science.gov (United States)

    Mushtaq, Sohail; Pickering, Juliet C.; Steers, Edward B. M.; Horvath, Peter; Whitby, James A.; Michler, Johann

    2010-11-01

    The influence of up to 0.8 % O2 on the Ar plasma in a dc analytical glow discharge was studied on Fe, Ti, Cu and Au samples using time of flight mass spectrometry and high resolution optical Fourier transform spectrometry. All positive ion signals decreased gradually by 2 to 3 orders of magnitude with increasing O2. In addition, a sudden 100-fold drop of the ion signals also occurred for Fe and Ti samples at 0.1 % and 0.05 % O2 concentrations, respectively. Optical emission spectra of Fe I, Fe II, Ti I and Ti II in Ar/O2 plasmas also showed a sudden drop of intensity at the same concentrations. This was accompanied by a 20-fold drop in sputter rate for Fe and Ti, whereas the sputter rate changed less for Cu and only slightly for Au. The role of surface and gas-phase processes will be discussed in the presentation.

  3. Hysteresis of fluctuation dynamics associated with a fireball in a magnetized glow discharge plasma in a currentless toroidal assembly

    Science.gov (United States)

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

    2016-09-01

    Floating potential fluctuations associated with an anode fireball in a glow discharge plasma in the toroidal vacuum vessel of the SINP tokamak are found to exhibit different kinds of oscillations under the action of vertical magnetic field of different strengths. While increasing the vertical magnetic field, the fluctuations have shown transitions as: chaotic oscillation → inverse homoclinic transition → intermittency → chaotic oscillation. However, on decreasing the magnetic field, the fluctuations are seen to follow: chaotic oscillations → homoclinic transition → chaotic oscillation; that is the intermittent feature is not observed. Fireball dynamics is found to be closely related to the magnetic field applied; results of visual inspection with a high speed camera are in close agreement with the fluctuations, and the fireball dynamics is found to be closely related to the transitions. The statistical properties like skewness, kurtosis, and entropy of the fluctuations are also found to exhibit this hysteresis behaviour.

  4. 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...

  5. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yanallah, K; Pontiga, F [Dpt. Fisica Aplicada II, Universidad de Sevilla (Spain); Castellanos, A [Dpt. Electronica y Electromagnetismo, Universidad de Sevilla (Spain)

    2011-02-09

    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.

  7. Impurity Studies of Cd(0.8)Zn(0.2)Te Crystals Using Photoluminescence and Glow Discharge Mass Spectroscopy

    Science.gov (United States)

    Su, Ching-Hua; Lehoczky, Sandor L.; Scripa, Rosalie N.

    2005-01-01

    Cd(1-x)Zn(x)Te semiconductor crystal is a highly promising material for room temperature x- and gamma-ray detector applications because of its high resistivity, long carrier lifetime, and relatively high hole and electron mobilities. This paper reports the investigation of the impurities in several Cd(1-x)Zn(x)Te (x = 0.20) crystals grown using the vertical Bridgman method under a Cd overpressure. The impurity concentrations were measured using glow discharge mass spectroscopy (GDMS). The energy states of the impurities were studied using photoluminescence (PL) spectroscopy at liquid helium temperature. The PL spectra showed a series of sharp high energy lines which are associated with free excitons and excitons bound to impurities as donors and acceptors in the crystals. The impurities also contributed to donor-acceptor pair recombination. The correlation between the GDMS and PL results will be reported.

  8. Study of Titanizing the Surface of Copper Substrates by the Double Glow Discharge Plasma Surface Alloying Technique

    Institute of Scientific and Technical Information of China (English)

    Zhang Yuefei; Chen Fei; Lü Junxia; Su Yongan; Xu Zhong

    2005-01-01

    This paper discusses a study in which Ti surface alloying has been performed on copper substrates by means of a double glow discharge plasma surface alloying technique. The micro-structure, the phase structure, the micro-hardness and the distribution of Ti concentration of alloying layer were investigated in detail by XRD, SEM and so on. The effect of process parameters on the alloying layer was studied. The experimental results show that a Ti solid solution with the precipitation Cu4Ti alloying layer has been formed on the copper surface. The thickness of the alloying layer is about 120μm and the surface titanium concentration gradually decreases from w (Ti) = 87% to w (Ti) = 4%. The micro-hardness of the alloying layer is between 300 HV ~ 800 HV. Source sputtering, surface absorption, ion bombarding and high temperature diffusion are the major factors that affect the alloying layer.

  9. Submillimeter-wave rotational spectra of DNC in highly excited vibrational states observed in an extended negative glow discharge

    Science.gov (United States)

    Amano, T.

    2011-05-01

    Rotational transitions of DNC have been observed in the submillimeter-wave region in an extended negative glow discharge in a gas mixture of CD 4 and N 2. The dissociative recombination reaction of DCND + with electrons is thought to be a dominant channel to produce DNC in highly excited vibrational states. The vibrational temperature for the ν3 vibrational mode is found to be about 4000 K, and the rotational lines in levels up to (0 0 8) are observed. The rotational and centrifugal distortion constants are determined for these states along with those for the (1 0 0) state. The measurement accuracy is high enough to determine some higher order vibration-rotation interaction constants.

  10. The influence of a transverse magnetic field on a subnormal glow discharge in air

    Indian Academy of Sciences (India)

    D C Jana; S S Pradhan

    2001-01-01

    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 magnetic field. With the help of Beckman’s expression [4] for the axial field and the electron density distribution in a transverse magnetic field the observed variation of current and voltage can be satisfactorily explained. The variation of axial electric field with transverse magnetic field can be represented to a fair degree of accuracy by the derived equation. The behaviour of residual current with magnetic field has been observed in these oscillations.

  11. 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.

  12. Characteristics of sheath-driven tangential flow produced by a low-current DC surface glow discharge plasma actuator

    Science.gov (United States)

    Shin, Jichul; Shajid Rahman, Mohammad

    2014-08-01

    An experimental investigation of low-speed flow actuation at near-atmospheric pressure is presented. The flow actuation is achieved via low-current ( \\lesssim 1.0 mA) continuous or pulsed DC surface glow discharge plasma. The plasma actuator, consisting of two sharp-edged nickel electrodes, produces a tangential flow in a direction from anode to cathode, and is visualized using high-speed schlieren photography. The induced flow velocity estimated via the schlieren images reaches up to 5 m/s in test cases. The actuation capability increases with pressure and electrode gap distances, and the induced flow velocity increases logarithmically with the discharge power. Pulsed DC exhibits slightly improved actuation capability with better directionality. An analytic estimation of induced flow velocity obtained based on ion momentum in the cathode sheath and gas dynamics in one-dimensional flow yields values similar to those measured.

  13. 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.

  14. 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.

  15. Differences in TLD 600 and TLD 700 glow curves derived from distict mixed gamma/neutron field irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Cavalieri, Tassio A.; Castro, Vinicius A.; Siqueira, Paulo T.D., E-mail: tassio.cavalieri@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear

    2013-07-01

    In Neutron Capture Therapy, a thermal neutron beam shall impinge on a specific nuclide, such as {sup 10}B, to promote a nuclear reaction which releases the useful therapeutic energy. A nuclear reactor is usually used as the neutron source, and therefore field contaminants such as gamma and high energy neutrons are also present in the field. However, mixed field dosimetry still stands as a challenge in some cases, due to the difficulty to experimentally discriminate the dose from each field component. For the mixed field dosimetry, the International Commission on Radiation end Units (ICRU) recommends the use of detector pairs with different responses for each beam component. The TLD 600/700 pair meets this need, because these LiF detectors have different Li isotopes concentration, with distinct thermal neutron responses because {sup 6}Li presents a much higher neutron capture cross section than does {sup 7}Li for low energy neutrons. TLD 600 is {sup 6}Li enriched while TLD 700 is {sup 7}Li enriched. However, depending on the neutron spectrum presented in the mixed field, TLD 700 response to thermal neutrons cannot be disregarded. This work aims to study the difference in TLD 600 and TLD 700 glow curves when these TLDs are submitted to mixed fields of different energy spectra and components balance. The TLDs were irradiated in a pure gamma source, and in mixed fields from an AmBe sealed source and from the IPEN/MB-01 reactor. These TLDs were read and had their two main dosimetric regions analyzed to observe the differences in the glow curves of these TLDs in each irradiation. Field components discrimination was achieved through Monte Carlo simulations run with MCNP radiation transport code. (author)

  16. Multiple solutions in the theory of direct current glow discharges: Effect of plasma chemistry and nonlocality, different plasma-producing gases, and 3D modelling

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, P. G. C.; Benilov, M. S. [Departamento de Física, CCCEE, Universidade da Madeira, Largo do Município, 9000 Funchal (Portugal)

    2013-10-15

    The work is aimed at advancing the multiple steady-state solutions that have been found recently in the theory of direct current (DC) glow discharges. It is shown that an account of detailed plasma chemistry and non-locality of electron transport and kinetic coefficients results in an increase of the number of multiple solutions but does not change their pattern. Multiple solutions are shown to exist for discharges in argon and helium provided that discharge pressure is high enough. This result indicates that self-organization in DC glow microdischarges can be observed not only in xenon, which has been the case until recently, but also in other plasma-producing gases; a conclusion that has been confirmed by recent experiments. Existence of secondary bifurcations can explain why patterns of spots grouped in concentric rings, observed in the experiment, possess in many cases higher number of spots in outer rings than in inner ones.

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

    Science.gov (United States)

    Akhmadeev, Yu. H.; Denisov, V. V.; Koval, N. N.; Kovalsky, S. S.; Lopatin, I. V.; Schanin, P. M.; Yakovlev, V. V.

    2017-01-01

    Generation of plasma in a pulsed non-self-sustained glow discharge with a hollow cathode with an area of ≥2 m2 at gas pressures of 0.4-1 Pa was studied experimentally. At an auxiliary arc-discharge current of 100 A and a main discharge voltage of 240 V, a pulse-periodic glow discharge with a current amplitude of 370 A, pulse duration of 340 μs, and repetition rate of 1 kHz was obtained. The possibility of creating a uniform gas-discharge plasma with a density of up to 1012 cm-3 and an electron temperature of 1 eV in a volume of >0.2 m3 was demonstrated. Such plasma can be efficiently used to treat material surfaces and generate pulsed ion beams with a current density of up to 15 mA/cm2.

  18. 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.

  19. Evaluation of a pulsed glow discharge time-of-flight mass spectrometer as a detector for gas chromatography and the influence of the glow discharge source parameters on the information volume in chemical speciation analysis.

    Science.gov (United States)

    Fliegel, Daniel; Fuhrer, Katrin; Gonin, Marc; Günther, Detlef

    2006-09-01

    The figures of merit of a pulsed glow discharge time-of-flight mass spectrometer (GD-TOFMS) as a detector for gas chromatography (GC) analysis were evaluated. The mass resolution for the GD-TOFMS was determined on FWHM in the high mass range (208Pb+) as high as 5,500. Precision of 400 subsequent analyses was calculated on 63Cu+ to be better than 1% RSD with no significant drift over the time of the analysis. Isotope precision based on the 63Cu+/65Cu+ ratio over 400 analyses was 1.5% RSD. The limits of detection for gaseous analytes (toluene in methanol as solvent) were determined to be as low as several hundred ppb or several hundred pg absolute without using any pre-concentration technique. Furthermore, the different GD source parameters like capillary distance, cathode-anode spacing, and GD source pressure with regards to the accessible elemental, structural, and molecular information were evaluated. It was demonstrated that each of these parameters has severe influence on the ratio of elemental, structural, and parent molecular information in chemical speciation analysis.

  20. 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.

  1. The effect of frequency on atmospheric pressure glow discharge in a pin-to-plate gap sustained by a resonant power supply

    Science.gov (United States)

    Wang, Yong Sheng; Ding, Wei Dong; Wang, Ya Nan; Wang, Jia Chen; Li, Fang; Fan, Chuan

    2016-06-01

    More and more researchers have been attracted to the research of atmospheric pressure glow discharge (APGD) because of its great prospect in numerous industrial applications. Nevertheless, almost all of the industrial applications are based on achievement of stable, large-volume, and uniform APGD. In a previous study, stable filamentary APGD was obtained by applying a resonant power supply between pin-to-plate electrodes which could limit the peak value of discharge current to supress the glow-to-arc transition through a series-wound resonance principle. The filamentary APGD is centimeter-level in the length but only several millimeters in diameter. Therefore, in order to obtain large-volume and uniform APGD, it is significant to study how to diffuse filamentary APGD in radial direction. With the increasing resonant frequency of alternating current discharge, excited particles (mainly including energetic electrons and trapped ions left from the previous half-cycle discharge) in the electrodes gap increase, which benefits obtaining stable self-sustaining APGD. In this paper, mechanism and law of the influence of resonant frequency on the diffusion of filamentary APGD in ambient air were studied. By comparing the photos of discharge plasma and waveforms of the discharge voltage and current, it is found that the volume of the glow discharge plasma enlarges as the resonant frequency of the power supply increases. It is very significant and anticipating to study how to obtain stable, large-volume, and uniform APGD in ambient air by the resonant power supply.

  2. Improving tribological properties of Ti-5Zr-3Sn-5Mo-15Nb alloy by double glow plasma surface alloying

    Science.gov (United States)

    Guo, Lili; Qin, Lin; Kong, Fanyou; Yi, Hong; Tang, Bin

    2016-12-01

    Molybdenum, an alloying element, was deposited and diffused on Ti-5Zr-3Sn-5Mo-15Nb (TLM) substrate by double glow plasma surface alloying technology at 900, 950 and 1000 °C. The microstructure, composition distribution and micro-hardness of the Mo modified layers were analyzed. Contact angles on deionized water and wear behaviors of the samples against corundum balls in simulated human body fluids were investigated. Results show that the surface microhardness is significantly enhanced after alloying and increases with treated temperature rising, and the contact angles are lowered to some extent. More importantly, compared to as-received TLM alloy, the Mo modified samples, especially the one treated at 1000 °C, exhibit the significant improvement of tribological properties in reciprocating wear tests, with lower specific wear rate and friction coefficient. To conclude, Mo alloying treatment is an effective approach to obtain excellent comprehensive properties including optimal wear resistance and improved wettability, which ensure the lasting and safety application for titanium alloys as the biomedical implants.

  3. "Glowing head" mice: a genetic tool enabling reliable preclinical image-based evaluation of cancers in immunocompetent allografts.

    Directory of Open Access Journals (Sweden)

    Chi-Ping Day

    Full Text Available Preclinical therapeutic assessment currently relies on the growth response of established human cell lines xenografted into immunocompromised mice, a strategy that is generally not predictive of clinical outcomes. Immunocompetent genetically engineered mouse (GEM-derived tumor allograft models offer highly tractable preclinical alternatives and facilitate analysis of clinically promising immunomodulatory agents. Imageable reporters are essential for accurately tracking tumor growth and response, particularly for metastases. Unfortunately, reporters such as luciferase and GFP are foreign antigens in immunocompetent mice, potentially hindering tumor growth and confounding therapeutic responses. Here we assessed the value of reporter-tolerized GEMs as allograft recipients by targeting minimal expression of a luciferase-GFP fusion reporter to the anterior pituitary gland (dubbed the "Glowing Head" or GH mouse. The luciferase-GFP reporter expressed in tumor cells induced adverse immune responses in wildtype mouse, but not in GH mouse, as transplantation hosts. The antigenicity of optical reporters resulted in a decrease in both the growth and metastatic potential of the labeled tumor in wildtype mice as compared to the GH mice. Moreover, reporter expression can also alter the tumor response to chemotherapy or targeted therapy in a context-dependent manner. Thus the GH mice and experimental approaches vetted herein provide concept validation and a strategy for effective, reproducible preclinical evaluation of growth and response kinetics for traceable tumors.

  4. Tailoring surface properties of polyethylene separator by low pressure 13.56 MHz RF oxygen plasma glow discharge

    Science.gov (United States)

    Li, Chun; Liang, Chia-Han; Huang, Chun

    2016-01-01

    Low-pressure plasma surface modification in a radio-frequency capacitively coupled glow discharge of oxygen gas was carried out to induce polar functional groups onto polyethylene membrane separator surfaces to enhance its hydrophilicity. The surface changes in surface free energy were monitored by static contact angle measurement. A significant increase in the surface energy of polyethylene membrane separators caused by the oxygen gas plasma modifications was observed. The static water contact angle of the plasma-modified membrane separator significantly decreased with the increase in treatment duration and plasma power. An obvious increase in the surface energy of the membrane separators owing to the oxidative effect of oxygen-gas-plasma modifications was also observed. Optical emission spectroscopy was carried out to analyze the chemical species generated by oxygen gas plasma surface modification. The variations in the surface morphology and chemical structure of the separators were confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS). XPS showed significantly higher surface concentrations of oxygen functional groups in the oxygen-gas-plasma-modified polymeric separator surfaces than in the unmodified polymeric separator surface. The experimental results show the important role of chemical species in the interaction between oxygen gas plasmas and the separator surface, which can be controlled by surface modification to tailor the hydrophilicity of the separator.

  5. 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.

  6. 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.

  7. Impact of low-pressure glow-discharge-pulsed plasma polymerization on properties of polyaniline thin films

    Science.gov (United States)

    Jatratkar, Aviraj A.; Yadav, Jyotiprakash B.; Deshmukh, R. R.; Barshilia, Harish C.; Puri, Vijaya; Puri, R. K.

    2016-12-01

    This study reports on polyaniline thin films deposited on a glass substrate using a low-pressure glow-discharge-pulsed plasma polymerization method. The polyaniline thin film obtained by pulsed plasma polymerization has been successfully demonstrated as an optical waveguide with a transmission loss of 3.93 dB cm-1, and has the potential to be employed in integrated optics. An attempt has been made to investigate the effect of plasma OFF-time on the structural, optical as well as surface properties of polyaniline thin film. The plasma ON-time has been kept constant and the plasma OFF-time has been varied throughout the work. The plasma OFF-time strongly influenced the properties of the polyaniline thin film, and a nanostructured and compact surface was revealed in the morphological studies. The plasma OFF-time was found to enhance film thickness, roughness, refractive index and optical transmission loss, whereas it reduced the optical band gap of the polyaniline thin films. Retention in the aromatic structure was confirmed by FTIR results. Optical studies revealed a π-π* electronic transition at about 317 nm as well as the formation of a branched structure. As compared with continuous wave plasma, pulsed plasma polymerization shows better properties. Pulsed plasma polymerization reduced the roughness of the film from 1.2 nm to 0.42 nm and the optical transmission loss from 6.56 dB cm-1 to 3.39 dB cm-1.

  8. Corrosion behavior of amorphous/nanocrystalline Al-Cr-Fe film deposited by double glow plasmas technique

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In order to improve the corrosion resistance of AZ31 magnesium alloy,the amorphous/nanocrystal Al-Cr-Fe film has been successfully prepared on AZ31 magnesium alloy by double glow plasma tech-nology.The amorphous/nanocrystalline consists of two different regions,i.e.,an amorphous layer on outmost surface and an underlying lamellar nanocrystalline layer with a grain size of less than 10 nm.The corrosion behavior of amorphous/nanocrystalline Al-Cr-Fe film in 3.5% NaCl solution is investi-gated using an electrochemical polarization measurement.Compared with the AZ31 magnesium alloy,the amorphous/nanocrystalline Al-Cr-Fe film exhibits more positive corrosion potentials and lower corrosion current densities than that of AZ31 magnesium alloy.XPS measurement reveals that the passive film formed on the Al-Cr-Fe film after the anodic polarization tests is strongly enriched in Cr2O3,Fe2O3 and Al2O3 at outer surface of the film and in the inner layer consists of Cr2O3,FeO and Al2O3.

  9. 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.

  10. Tribological Properties of Mo-N Hard Coatings on Ti6Al4V by Double Glow Discharge Technique

    Institute of Scientific and Technical Information of China (English)

    Xiuyan LI; Bin TANG; Junde PAN; Daoxin LIU; Zhong XU

    2003-01-01

    Mo-N hard coatings on Ti6Al4V were formed using double glow discharge technique. The fundamental coating properties,such as the phase, hardness and elastic modulus were investigated. The tribological performances of the coatings in dry wear condition were studied by means of ball-on-disc wear machine. The experimental results showed that the thickness of the Mo-N hard coating was about 10 μm. The coating was single fcc γ-Mo2N phase with (200) preferred orientation. The hardness and the elastic modulus of the coating was 13.80 GPa and 261.65 GPa respectively. The surface treatment enhanced the hardness and elastic modulus of the surface of Ti6Al4V base greatly. With GCr15 slider ball, the friction coefficient of the Mo-N hard coatingwas in the range of 0.56~0.65 at the steady state. Though the coating did not show friction reducing effect, it improved the wear resistance of Ti6Al4V greatly.

  11. 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.

  12. Potential Applicability of Persuasive Communication to Light-Glow Reduction Efforts: A Case Study of Marine Turtle Conservation

    Science.gov (United States)

    Kamrowski, Ruth L.; Sutton, Stephen G.; Tobin, Renae C.; Hamann, Mark

    2014-09-01

    Artificial lighting along coastlines poses a significant threat to marine turtles due to the importance of light for their natural orientation at the nesting beach. Effective lighting management requires widespread support and participation, yet engaging the public with light reduction initiatives is difficult because benefits associated with artificial lighting are deeply entrenched within modern society. We present a case study from Queensland, Australia, where an active light-glow reduction campaign has been in place since 2008 to protect nesting turtles. Semi-structured questionnaires explored community beliefs about reducing light and evaluated the potential for using persuasive communication techniques based on the theory of planned behavior (TPB) to increase engagement with light reduction. Respondents ( n = 352) had moderate to strong intentions to reduce light. TPB variables explained a significant proportion of variance in intention (multiple regression: R 2 = 0.54-0.69, P persuasion potential for future communications. Selective legislation and commitment strategies may be further useful strategies to increase community light reduction. As artificial light continues to gain attention as a pollutant, our methods and findings will be of interest to anyone needing to manage public artificial lighting.

  13. Rf glow discharge optical emission spectrometry for the analysis of arrays of Ni nanowires in nanoporous alumina and titania membranes

    Energy Technology Data Exchange (ETDEWEB)

    Prida, V.M.; Bordel, N.; Hernando, B. [Depto. Fisica, Universidad Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Navas, D.; Pirota, K.R.; Vazquez, M. [Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, 28049 Madrid (Spain); Hernandez-Velez, M. [Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, 28049 Madrid (Spain); Depto. Fisica Aplicada, C-XII, Universidad Autonoma Madrid, Cantoblanco, 28049 Madrid (Spain); Menendez, A.; Pereiro, R.; Sanz-Medel, A. [Depto. Quimica Fisica y Analitica, Facultad de Quimica, Julian Claveria 8, 33006 Oviedo (Spain)

    2006-05-15

    Anodic alumina (Al{sub 2}O{sub 3}) and titania (TiO{sub 2}) nanoporous oxide membranes are among the most widely studied self-organized nanopore templates, formed by uniform and well aligned arrays of synthetized nanometric pores or tubes. Here, we perform a comparative study of the depth profiling analysis in self-ordered alumina and titania nanoporous membrane templates by means of the radiofrequency glow discharge coupled to optical emission spectrometry (rf-GD-OES) technique. The densely packed columnar arrays of hexagonally self-ordered nanoporous alumina membranes investigated, with an average inner pore diameter of 35 nm and 105 nm interspacing, give an uniform thickness pore length about more than 5 {mu}m, depending on the anodization time. Meanwhile, the analysis of the anodized titania nanotubes, with an average inner pore diameter of 100 nm and 40 nm wall thickness, shown to be about 300 nm in length. Each type of membranes were also studied in both cases, when the nanopores were empty and after filling with electrodeposited Ni. The direct analysis by rf-GD-OES reveals the ability of this technique to control the quality of these so synthesized nanocomposites formed by electrodeposited Ni nanowires into the alumina and titania nanoporous templates. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Rf glow discharge optical emission spectrometry for the analysis of arrays of Ni nanowires in nanoporous alumina and titania membranes

    Science.gov (United States)

    Prida, V. M.; Navas, D.; Pirota, K. R.; Hernandez-Velez, M.; Menéndez, A.; Bordel, N.; Pereiro, R.; Sanz-Medel, A.; Hernando, B.; Vazquez, M.

    2006-05-01

    Anodic alumina (Al2O3) and titania (TiO2) nanoporous oxide membranes are among the most widely studied self-organized nanopore templates, formed by uniform and well aligned arrays of synthetized nanometric pores or tubes. Here, we perform a comparative study of the depth profiling analysis in self-ordered alumina and titania nanoporous membrane templates by means of the radiofrequency glow discharge coupled to optical emission spectrometry (rf-GD-OES) technique. The densely packed columnar arrays of hexagonally self-ordered nanoporous alumina membranes investigated, with an average inner pore diameter of 35 nm and 105 nm interspacing, give an uniform thickness pore length about more than 5 μm, depending on the anodization time. Meanwhile, the analysis of the anodized titania nanotubes, with an average inner pore diameter of 100 nm and 40 nm wall thickness, shown to be about 300 nm in length. Each type of membranes were also studied in both cases, when the nanopores were empty and after filling with electrodeposited Ni. The direct analysis by rf-GD-OES reveals the ability of this technique to control the quality of these so synthesized nanocomposites formed by electrodeposited Ni nanowires into the alumina and titania nanoporous templates.

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

    Science.gov (United States)

    Xu, Jinzhou; Guo, Ying; Xia, Lei; Zhang, Jing

    2007-08-01

    An asymmetric electric voltage pulse source (2-20 kHz, Vp-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 (~460 Torr). When the source frequency increases continuously from 2.0 to 12.0 kHz or in reverse under a fixed output voltage of Vp-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.

  16. Generation of multiple toroidal dust vortices by a non-monotonic density gradient in a direct current glow discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Manjit, E-mail: manjit@ipr.res.in; Bose, Sayak; Chattopadhyay, P. K.; Sharma, D.; Ghosh, J.; Saxena, Y. C. [Institute for Plasma Research, Gandhinagar 382428 (India); Thomas, Edward [Department of Physics, Auburn University, Auburn, Alabama 36849 (United States)

    2015-09-15

    Observation of two well-separated dust vortices in an unmagnetized parallel plate DC glow discharge plasma is reported in this paper. A non-monotonic radial density profile, achieved by an especially designed cathode structure using a concentric metallic disk and ring of different radii, is observed to produce double dust tori between cathode and anode. PIV analysis of the still images of the double tori shows oppositely rotating dust structures between the central disk and the ring. Langmuir probe measurements of background plasma shows a non-uniform plasma density profile between the disk and the ring. Location and sense of rotation of the dust vortices coincides with the location and direction of the radial gradient in the ion drag force caused by the radial density gradient. The experimentally observed dust vorticity matches well with the calculated one using hydrodynamic formulations with shear in ion drag dominating over the dust charge gradient. These results corroborate that a radial gradient in the ion drag force directed towards cathode is the principal cause of dust rotation.

  17. Shock compression of glow discharge polymer (GDP): density functional theory (DFT) simulations and experiments on Sandia's Z-machine

    Science.gov (United States)

    Mattsson, Thomas R.; Cochrane, K. R.; Ao, T.; Lemke, R. W.; Flicker, D. G.; Schoff, M. E.; Blue, B. E.; Hamel, S.; Herrmann, M. C.

    2015-11-01

    Glow discharge polymer (GDP) is used extensively as capsule/ablation material in inertial confinement fusion (ICF) capsules. Accurate knowledge of the equation of state (EOS) under shock and release is particularly important for high-fidelity design, analysis, and optimization of ICF experiments since the capsule material is subject to several converging shocks as well as release towards the cryogenic fuel. We performed Density Functional Theory (DFT) based quantum molecular dynamics (QMD) simulations, to gain knowledge of the behavior of GDP - including the effect of changes in chemical composition. The shock pressures calculated from DFT are compared experimental data taken on magnetically launched flyer plate impact experiments on at Sandia's Z-machine. Large GDP samples were grown in a planar geometry to improve the sample quality and maintained in a nitrogen atmosphere following manufacturing, thus allowing for a direct comparison to the DFT/QMD simulations. Sandia National Laboratories is a multi program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's NNSA under contract DE-AC04-94AL85000.

  18. Shock compression of glow discharge polymer (GDP): density functional theory (DFT) simulations and experiments on Sandia's Z machine

    Science.gov (United States)

    Cochrane, Kyle R.; Ao, T.; Lemke, R. W.; Hamel, S.; Schoff, M. E.; Blue, B. E.; Herrmann, M. C.; Mattsson, T. R.

    2014-03-01

    Glow discharge polymer (GDP) is used extensively as capsule/ablation material in inertial confinement fusion (ICF) capsules. Accurate knowledge of the equation of state (EOS) under shock and release is particularly important for high-fidelity design, analysis, and optimization of ICF experiments since the capsule material is subject to several converging shocks as well as release towards the cryogenic fuel. We performed Density Functional Theory (DFT) based quantum molecular dynamics (QMD) simulations, to gain knowledge of the behavior of GDP - for example regarding the role of chemical dissociation during shock compression, we find that the dissociation regime along the Hugoniot extends from 50 GPa to 250 GPa. The shock pressures calculated from DFT are compared experimental data taken at Sandia's Z-machine. The GDP samples were grown in a planar geometry to improve the sample quality and maintained in a nitrogen atmosphere following manufacturing, thus allowing for a direct comparison to the DFT/QMD simulations. Sandia National Laboratories is a multi program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's NNSA under contract DE-AC04-94AL85000.

  19. Effect of DC glow discharge plasma treatment on PET/TiO(2) thin film surfaces for enhancement of bioactivity.

    Science.gov (United States)

    Navaneetha Pandiyaraj, K; Selvarajan, V; Rhee, Young Ha; Kim, Hyoung Woo; Pavese, Matteo

    2010-08-01

    In this paper, the surfaces of PET/TiO(2) thin film were modified by DC glow discharge plasma as a function of discharge potentials for improving the bioactivity. The hydrophilicity of the plasma-treated PET/TiO(2) film was measured by contact angle measurement and the surface energy was estimated by using Fowkes method. The structural and chemical composition of the plasma-treated PET/TiO(2) was analysed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Immersion in a simulated body solution (SBF) solution was used to evaluate the bioactivity of the plasma-treated PET/TiO(2) samples in vitro. It was found that the plasma treatment modified the surfaces both in chemical composition and crystallinity which makes surface of the PET/TiO(2) to become more hydrophilic compared with untreated one. Analytical and microstructural investigations of SBF results, showed considerable higher rates of apatite formation on the plasma-treated PET/TiO(2) compared to the untreated films.

  20. Ambient desorption/ionization mass spectrometry using a liquid sampling-atmospheric glow discharge (LS-APGD) ionization source.

    Science.gov (United States)

    Marcus, R Kenneth; Burdette, Carolyn Q; Manard, Benjamin T; Zhang, Lynn X

    2013-10-01

    A novel approach to ambient desorption/ionization mass spectrometry (ADI-MS) is described, based on a recently developed liquid sampling-atmospheric pressure glow discharge (LS-APGD) ionization source. The device is essentially unmodified relative to its implementation in elemental mass spectrometry, where the operational space is characterized by low operation power (LS-APGD source is mounted onto the source interface of a Thermo Finnigan LCQ Advantage Max quadrupole ion trap mass spectrometer without modifications to the instrument faceplate or ion optics. Described here is the initial evaluation of the roles of source geometry and working parameters, including electrolytic solution composition and plasma current, on the response of caffeine residues, with preliminary limits of detection based on the relative standard deviation of the spectral background suggested to be on the 10-pg level. Demonstrative spectra are presented for green tea extracts and raw leaves, coffee beans, a dried (raw) tobacco leaf, an analgesic tablet, and paper currency. Versatility is further revealed through the determination of components in common cigarette smoke. In each case, the spectra are characterized by (M + H)(+) species of the expected constituents. The capacity for a single source to perform both in solution and particulate elemental analysis (as shown previously) and ADI of molecular species is unique in the realm of mass spectrometry.

  1. 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.

  2. Spatially resolved measurements to improve analytical performance of solution-cathode glow discharge optical-emission spectrometry

    Science.gov (United States)

    Schwartz, Andrew J.; Ray, Steven J.; Chan, George C.-Y.; Hieftje, Gary M.

    2016-11-01

    Past studies of the solution-cathode glow discharge (SCGD) revealed that elemental and molecular emission are not spatially homogenous throughout the source, but rather conform to specific zones within the discharge. Exploiting this inhomogeneity can lead to improved analytical performance if emission is collected only from regions of the discharge where analyte species emit strongly and background emission (from continuum, elemental and/or molecular sources) is lower. Effects of this form of spatial discrimination on the analytical performance of SCGD optical emission spectrometry (OES) have been investigated with an imaging spectrograph for fourteen atomic lines, with emphasis on detection limits and precision. Vertical profiles of the emission intensity, signal-to-background ratio, and signal-to-noise ratio were collected and used to determine the optimal region to view the SCGD on a per-element basis. With optimized spatial filtering, detection limits ranged from 0.09-360 ppb, a 1.4-13.6 fold improvement over those obtained when emission is collected from the full vertical profile (1.1-840 ppb), with a 4.2-fold average improvement. Precision was found to be unaffected by spatial filtering, ranging from 0.5-2.6% relative standard deviation (RSD) for all elements investigated, closely comparable to the 0.4-2.4% RSD observed when no spatial filtering is used. Spatial profiles also appear useful for identifying optimal line pairs for internal standardization and for flagging the presence of matrix interferences in SCGD-OES.

  3. Nanostructured TaxC interlayer synthesized via double glow plasma surface alloying process for diamond deposition on cemented carbide

    Science.gov (United States)

    Rong, Wolong; Hei, Hongjun; Zhong, Qiang; Shen, Yanyan; Liu, Xiaoping; Wang, Xin; Zhou, Bing; He, Zhiyong; Yu, Shengwang

    2015-12-01

    The aim in this work was to improve the adhesion of diamond coating with pre-deposition of a TaxC interlayer on cemented carbide (WC-Co) substrate by double glow plasma surface alloying technique. The following deposition of diamond coating on the interlayer was performed in a microwave plasma chemical vapor deposition (MPCVD) reactor. TaxC interlayer with an inner diffusion layer and an outer deposition layer was composed of Ta2C and TaC nanocrystalline, and it exhibited a special compact surface morphology formed of flower-shaped pits. As the gradual element distributions existed in the diffusion layer, the interlayer displayed a superior adherence to the substrate with significantly enhanced surface microhardness to the original substrate. After CVD process, the preferred orientation of TaC changed from (2 2 2) to (2 0 0) plane, and a uniform and tense diamond coating with adhesion referred to class HF 2 at least (Verein Deutscher Ingenieure 3198 norm) was obtained on the interlayered substrate. It indicated that the diffusion of Co was effectively inhibited by the formation of TaxC diffusion-deposition interlayer. The TaxC interlayer is most likely to improve the performance of diamond coatings used in cutting tools.

  4. 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...

  5. Validation of gas temperature measurements by OES in an atmospheric air glow discharge with water electrode using Rayleigh scattering

    Energy Technology Data Exchange (ETDEWEB)

    Verreycken, T; Van Gessel, A F H; Pageau, A; Bruggeman, P, E-mail: p.j.bruggeman@tue.n [Eindhoven University of Technology, Department of Applied Physics, PO Box 513, 5600 MB Eindhoven (Netherlands)

    2011-04-15

    Rayleigh scattering is used to determine the gas temperature of an atmospheric pressure dc excited glow discharge in air with a water electrode. The obtained temperatures are compared with calculated rotational temperatures measured by optical emission spectroscopy of OH(A-X) and N{sub 2}(C-B). At a current of 15 mA a deviation is found between T{sub rot}(OH) and the gas temperature obtained from Rayleigh scattering of about 1000 K. The gas temperatures obtained from Rayleigh scattering, N{sub 2}(C) and OH(A) in the positive column are, respectively, 2600 {+-} 100 K, 2700 {+-} 150 K and 3600 {+-} 200 K. It is shown that the rotational temperature of N{sub 2}(C) is a reliable measurement of the gas temperature while this is not the case for OH(A). The results are explained in the context of quenching processes of the excited states. Spatially resolved gas temperatures in both longitudinal and radial directions are presented. The observed strong temperature gradients near the electrodes are checked to be consistent with the power dissipation and the heat transfer in the discharge. The effect of the polarity of the water electrode and filamentation on the measured temperatures is discussed.

  6. Interactive 3D Visualization of the Great Lakes of the World (GLOW) as a Tool to Facilitate Informal Science Education

    Science.gov (United States)

    Yikilmaz, M.; Harwood, C. L.; Hsi, S.; Kellogg, L. H.; Kreylos, O.; McDermott, J.; Pellett, B.; Schladow, G.; Segale, H. M.; Yalowitz, S.

    2013-12-01

    Three-dimensional (3D) visualization is a powerful research tool that has been used to investigate complex scientific problems in various fields. It allows researchers to explore and understand processes and features that are not directly observable and help with building of new models. It has been shown that 3D visualization creates a more engaging environment for public audiences. Interactive 3D visualization can allow individuals to explore scientific concepts on their own. We present an NSF funded project developed in collaboration with UC Davis KeckCAVES, UC Davis Tahoe Environmental Research Center, ECHO Lake Aquarium & Science Center, and Lawrence Hall of Science. The Great Lakes of the World (GLOW) project aims to build interactive 3D visualization of some of the major lakes and reservoirs of the world to enhance public awareness and increase understanding and stewardship of freshwater lake ecosystems, habitats, and earth science processes. The project includes a collection of publicly available satellite imagery and digital elevation models at various resolutions for the 20 major lakes of the world as well as the bathymetry data for the 12 lakes. It also includes the vector based 'Global Lakes and Wetlands Database (GLWD)' by the World Wildlife Foundation (WWF) and the Center for Environmental System Research University of Kassel, Germany and the CIA World DataBank II data sets to show wetlands and water reservoirs at global scale. We use a custom virtual globe (Crusta) developed at the UC Davis KeckCAVES. Crusta is designed to specifically allow for visualization and mapping of features in very high spatial resolution (learn about the lake and watershed processes as well as geologic processes (e.g. faulting, landslide, glacial, volcanic) that have shaped these lakes. With the advances in 3D imaging technology, the hardware is becoming more affordable and accessible. Affordable 3D projectors, monitors and TVs will allow schools and informal science centers

  7. 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.

  8. Evaluation of pumpdown curves illustrated for a glow discharge source; Evaluierung von Abpumpkurven am Beispiel einer Glimmentladungsquelle

    Energy Technology Data Exchange (ETDEWEB)

    Klemm, D.; Hoffmann, V. [Leibniz-Institut fuer Festkoerper- und Werkstoffforschung, Dresden (Germany); Edelmann, C.

    2008-06-15

    In the present state, the GLOW DISCHARGE OPTICAL EMISSION SPECTROMETRY (= GD-OES) is distinguished by an extraordinary quick material analysis. The analysis time (gross time of analysis 2 - 5 minutes) is determined mainly by the pumping time of the source of the equipment, the reliability of the spectral analysis is - especially in the case of thin films (film thickness < 100 nm) - determined by the cleanness of the gas in the source and the surface of the source. In the case of the used commercial spectrometer equipment it was possible to reduce the evacuation time and the final pressure in the source for improvement of the cleanness of the gas at the place of the analysis with the help of a proper conduction of the venting and pumping process and by a proper dimensioning and construction of the pumping set of the equipment. An automatic and computer aided evaluation of the pressure vs. time run in the source chamber gives advises to the user of the equipment about possible leaks (caused e.g. by the wear of sealing) in the equipment or about contamination of inner surfaces, because the pressure vs. time run in the chamber is determined by parameters which are characteristic of the equipment (e.g. effective pumping speed, leak rate, and outgassing or desorption rate). By variation of these parameters the calculated pressure vs. time run is fitted to the experimental measured pressure vs. time curve. Parameters found by this method are important characteristics describing the situation of the equipment (source and pumping set). On the base of these results the user of the device can carry out a leakage detection or clean or replace components of the instrument in time. This check of the device increases the reproducibility of the analysis of materials. (orig.)

  9. Accounting protesting and warm glow bidding in Contingent Valuation surveys considering the management of environmental goods--an empirical case study assessing the value of protecting a Natura 2000 wetland area in Greece.

    Science.gov (United States)

    Grammatikopoulou, Ioanna; Olsen, Søren Bøye

    2013-11-30

    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 for such selection bias by using a sample selection model. In our empirical sample, using the typical approach of removing protesters from the analysis, the value of protecting the wetland is significantly underestimated by as much as 46% unless correcting for selection bias.

  10. Glow curve analysis of β-particles irradiated Na{sub 21}Mg(SO{sub 4}){sub 10}Cl{sub 3}:Dy phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Kore, Bhushan P. [Department of Physics, R.T.M. Nagpur University, Nagpur 440033 (India); Dhoble, N.S. [Department of Chemistry, Sevadal Mahila Mahavidyalaya, Nagpur 440009 (India); Dhoble, S.J., E-mail: sjdhoble@rediffmail.com [Department of Physics, R.T.M. Nagpur University, Nagpur 440033 (India)

    2014-01-15

    Dy doped Na{sub 21}Mg(SO{sub 4}){sub 10}Cl{sub 3} phosphor was prepared by modifying the solid state method and the formation of the compound was confirmed by X-ray diffraction (XRD) study. Morphology of the phosphor was analyzed by scanning electron microscopy (SEM). The thermally stimulated luminescence (TSL) studies of Dy doped Na{sub 21}Mg(SO{sub 4}){sub 10}Cl{sub 3} samples show the complex glow curve. Powder samples of Na{sub 21}Mg(SO{sub 4}){sub 10}Cl{sub 3}:Dy were irradiated by 2.2 MeV β-particles within dose range of 100–16,000 mGy. Analysis of the thermoluminescence glow curves was carried out by T{sub m}–T{sub stop} and glow curve deconvolution (GCD) method. Trapping parameters (activation energy and frequency factor) for individual deconvoluted peaks were obtained by Chen's peak shape method. The comparison of trapping parameters between γ-ray irradiated and β-particles irradiated Na{sub 21}Mg(SO{sub 4}){sub 10}Cl{sub 3}:Dy phosphor were also studied. -- Highlights: • This study reports the thermoluminescence properties of Na{sub 21}Mg(SO{sub 4}){sub 10}Cl{sub 3}:Dy phosphor for β-particles irradiation. • The main focus of this study is on the response of the phosphor to β-particles and difference in behavior from γ-ray irradiation. • Good linearity was observed for measuring the doses of β-particles upto 1500 mGy.

  11. Modulation of the thermoluminescence glow curve of sol-gel synthesized SiO{sub 2} and Si O-2:Eu through thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Salas J, Ch. J.; Cruz V, C. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Bernal, R. [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico); Castano, V. M., E-mail: salasjuarez@gimmunison.com [UNAM, Centro de Fisica Aplicada y Tecnologia Avanzada, Apdo. Postal 1-1010, 76000 Queretaro, Qro. (Mexico)

    2015-10-15

    Full text: Due to the increasing use of ionizing radiations, is necessary to monitor the radiation fields and exposure doses in facilities in which they are used. Different facilities or applications involve the use of different radiation and doses, and the sort of needed dosimetry also varies. Sometimes a conventional thermoluminescence (Tl) dosimetry satisfy the requirements since the record of the accumulated dose in a time interval is enough, but other cases could require for real-time measurement of a radiation field, being required a non-Tl dosimetric technique. On the other hand, different applications involve the use of different dose ranges, and so dosimeters with different sensitivities are needed. To solve the diverse needs of radiation detectors and dosimeters, a lot of phosphors materials has been characterized concerning their dosimetric capabilities. For medical application, biocompatible materials are desirable. In this work, we present experimental evidence that Sol-Gel synthesized SiO{sub 2} and SiO{sub 2}:Eu phosphors exhibit Tl glow curves composed by the superposition of several individual glow peaks each located at different temperature ranging from values below 100 up to temperatures greater than 400 degrees C, whose relative sensitivities can be modified by subjecting the phosphors to different thermal annealing. By modulating the relative intensities of the individual Tl peaks, glow curves with different shapes are obtained in such a way that SiO{sub 2} and SiO{sub 2}:Eu can be used to develop dosimeters useful for different dose ranges, and for both, conventional thermoluminescence dosimetry and non-thermoluminescence afterglow-based) dosimetry. (Author)

  12. [Evaluation of potentiality of combined SHF- and glow discharge in intensification of carbon dioxide and hydrogen processing within life support system].

    Science.gov (United States)

    Klimarev, S I

    2011-01-01

    The article reports an experimental carbon dioxide hydration process in combined SHF- and glow discharge, and describes a design of SHF plasmatrones for CO2 processing at air pressure and in an integrated unit. Maximal transformation of 80% CO2 per a run was reached with the total input power of no more than 0.9 kW. Thermal zero lag of plasma forming, essentially instant and timely engagement and disengagement of thermal action on CO2-H2 mixture renders SHF-energy applicable to intensification of next generation life support technologies, processing of these gases within atmosphere regeneration system specifically.

  13. 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.

  14. Experiment and analysis of an atmospheric DC glow discharge device%大气压直流辉光放电装置的实验与分析

    Institute of Scientific and Technical Information of China (English)

    刘坤; 廖峥; 侯世英; 唐飞; 王晓浩; 敬刚

    2013-01-01

    In order to reduce the volume and be used in portable instruments, a line-cylinder atmospheric glow discharge device with a 1. 92 mm discharge gap is designed. It mainly consists of an inner line electrode and an outer cylinder electrode. The diameters of the line and cylinder electrodes are 0. 16 and 4 mm, respectively. The transition from corona discharge to glow discharge is observed and explained. By using discharge waveform and photo, it has been verified that it is a glow discharge. The calculation methods of vibrational temperature and rotational temperature are deduced by use of the N2 second positive band system. The emission spectrum of the plasma is collected by spectrometer (Acton Spectrapro 2500i). From calculation, it is found that the vibrational temperature of the plasma is about 2 360 K and the rotational temperature of the plasma is about 830 K. The device is used as an ion source in the ambient mass spectrometer. The experiment results show that the plasma generated by DC glow discharge can well ionize the formic acid, acetic acid, and phenol, etc.%为了能减小放电装置的体积,以应用于便携式仪器,设计了线-筒型大气压直流辉光放电装置,放电间隙仅1.92 mm.它主要由内线电极、外筒电极组成,线电极直径为0.16 mm,筒电极直径为4 mm.观察并说明了从电晕放电向辉光放电过渡的过程.通过放电波形和图像验证了其处于辉光放电状态.推导了利用氮气第二正带系计算振动温度和转动温度的算法,并利用光谱仪(Acton Spectrapr0 2500i)采集所产生的等离子体的发射光谱,计算得到该等离子体的振动温度在2 360 K左右,转动温度在830 K左右.将该装置作为离子源应用于敞开式质谱中,实验结果表明,该直流大气压辉光放电形成的等离子体可以很好地离子化甲酸、乙酸、苯酚等物质.

  15. Performance of direct injection methanol engine using the fuel jet impingement and diffusion. ; Comparison between the spark plug and glow plug ignitions. Nenryo funryu no shototsu kakusan wo riyoshita chokufun methanol kikan no seino. ; Spark plug oyobi glow plug chakka hoshiki no hikaku

    Energy Technology Data Exchange (ETDEWEB)

    Kato, S.; Onishi, S.

    1993-01-20

    The purpose of this paper is to compare the performance of direct fuel injection methanol engines with the spark plug and glow plug ignition systems. These methanol engines utilize the formation of fuel-air mixture by the fuel jet impingement and diffusion. Engine performance and cylinder pressure for the both ignition systems were analyzed. Piezoelectric pressure indicator was used for the cylinder pressure measurements, and combustion analyzer was used for their analyses. In order to estimate engine performance, effects of load and engine speed were analyzed. Consequently, almost the same brake thermal efficiencies (maximum value of 42%) were obtained for both ignition systems. For the glow plug ignition system, the combustion noise and NOx emission were lower than the spark plug engine. The NOx emission did not excess 500ppm with the glow plug ignition system. In the impingement and diffusion method, both the piston attached type impingement part and cylinder head fixed type one were applicable. 4 refs., 9 figs., 2 tabs.

  16. Detection of some industrially relevant elements in water by electrolyte cathode atmospheric glow discharge optical emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bencs, László, E-mail: bencs.laszlo@wigner.mta.hu [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, PO Box 49, Budapest H-1525 (Hungary); Laczai, Nikoletta; Mezei, Pál [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, PO Box 49, Budapest H-1525 (Hungary); Cserfalvi, Tamás [T. Meisel Laboratory, Aqua-Concorde R& D LLC, Budapest, Bosnyák utca 11, H-1145 (Hungary)

    2015-05-01

    An electrolyte cathode atmospheric glow discharge optical emission spectrometry (ELCAD-OES) method was developed for the detection of the industrially relevant In, Rh and Te in water samples. Acid/additive type, sample pH and flow rate were optimized. The UV–Vis spectrum was scanned for analytical lines, free from spectral overlap interferences, and sensitive enough for quantifying the analytes at mg L{sup −1} or lower levels. In several cases, the background spectrum of the ELCAD hindered the use of conventional, resonant analytical lines in the UV due to overlaps with bands of molecular species (e.g., OH, NO, N{sub 2}). Te and Rh showed lower emission intensities than In (determined at In I 451.1 nm), even using the most sensitive, interference-free transitions (i.e., Te I 214.3 nm, Te I 238.6 nm and Rh I 437.5 nm). The emission intensities were highly sample pH dependent, i.e., analytical signals could only be detected at pH levels lower than 2. Conversely, the use of acidity lower than pH 1 caused lower plasma volume, due to its contraction into the sample introduction capillary, and discharge instability in terms of its frequent self-extinction. The detection limits for In, Rh and Te were 0.01, 0.5 and 2.4 mg L{sup −1}, respectively. Calibration curves were linear up to 100–150 mg L{sup −1}. The precision for In, Rh and Te in aqueous standards, expressed as relative standard deviation (RSD), was not higher than 4.6%, 6.4% and 7.4%, respectively. Samples with high salt content (e.g., well water) caused positive matrix effects (i.e., 2.0- to 3.6-fold signal enhancements), but also ~ 1.5 times higher RSDs. - Highlights: • An ELCAD-OES method is developed for the monitoring of In, Rh and Te in waters. • The UV–Vis emission spectrum was studied for interference-free spectral lines. • Effects of sample pH, acid-type on signal intensities and GD voltage were studied. • Calibration and analytical figures for low- to high-salinity waters were

  17. Ignition's glow: Ultra-fast spread of global cortical activity accompanying local "ignitions" in visual cortex during conscious visual perception.

    Science.gov (United States)

    Noy, N; Bickel, S; Zion-Golumbic, E; Harel, M; Golan, T; Davidesco, I; Schevon, C A; McKhann, G M; Goodman, R R; Schroeder, C E; Mehta, A D; Malach, R

    2015-09-01

    ) with an ultra-fast spread of signals of lower magnitude that invaded selected sites throughout fronto-parietal cortical areas. Our results are compatible with local models in demonstrating a clear task-dependence of the 300 ms fronto-parietal activation. However, they also reveal a more global component of low-magnitude and poor content selectivity that rapidly spreads into fronto-parietal sites. The precise functional role of this global "glow" remains to be elucidated.

  18. Incorporation of the electron energy equation into the hybrid Monte Carlo - fluid model for glow discharge: the applicability and reliability of the model

    Science.gov (United States)

    Eylenceoglu, Ender; Rafatov, Ismail; Kudryavtsev, Anatoly

    2016-09-01

    A modification of the conventional hybrid Monte Carlo - fluid model for glow discharge, which incorporates the electron energy equation, is considered. In the proposed model electrons are separated into two groups, namely, high energetic fast and low energetic slow (bulk) electrons. Density profiles of ions, slow electrons, and meta-stable particles are determined from the solution of corresponding continuity equations. Fast electrons, which are responsible for ionization and excitation events in the discharge, are simulated by the Monte-Carlo method. The temperature profile for slow electrons is obtained from the solution of the energy balance equation. The transport (mobility and diffusion) coefficients as well as the reaction rates for slow electrons are determined as functions of the electron temperature. Test calculations are carried out for the direct current glow discharge in argon within two-dimensional geometry. Comparison of the computed results with those obtained from the conventional fluid and hybrid models and the experimental data is done, the applicability and reliability of the proposed model is studied in details.

  19. Influence of pulsed d. c. -glow-discharge on the phase constitution of nitride layers during plasma nitrocarburizing of sintered materials

    Energy Technology Data Exchange (ETDEWEB)

    Rie, K.T.; Schnatbaum, F. (Inst. fuer Oberflaechentechnik und Plasmatechnische Werkstoffentwicklung, Technische Univ. Braunschweig (Germany))

    1991-07-07

    In the past it was shown that plasma diffusion treatment of sintered materials has several advantages over conventional processes such as gas or salt bath nitriding and nitrocarburizing. The large number of parameters in plasma diffusion treatment allows close control of the process so that surface layers with defined microstructures and properties can be obtained. Durig plasma diffusion treatment the phase constitution of the nitride compound layer can be influenced by varying the gas mixture. By using a pulsed d.c. glow discharge the phase constitution and the microstructure of the compound layer can be influenced by varying the pulse duration and pulse repetition time. The number of micropores in the compound layer can be reduced in a pulsed d.c. glow discharge by pulsing the plasma, i.e. by reducing the plasma power. The phase constitution can be influenced by the pulse duration and pulse repetition time. With short pulse duration and long pulse repetition time the formation of Fe{sub 3}C in the compound layer can be suppressed. The amount of {gamma}' and {epsilon} phase present can be influenced. (orig.).

  20. Evolution of the Tl glow curve of Zn S:Mn nanocrystalline; Evolucion de la curva de brillo Tl de ZnS:Mn nanocristalino

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz H, A. A. [Universidad Autonoma de San Luis Potosi, Doctorado en Ingenieria y Ciencia de Materiales, 78000 San Luis Potosi (Mexico); Mendez G, V. H. [Universidad Autonoma de San Luis Potosi, Coordinacion para la Innovacion y Aplicacion de la Ciencia y la Tecnologia, 78000 San Luis Potosi (Mexico); Perez A, M. L.; Ortega S, J. J.; Araiza, J. J. [Universidad Autonoma de Zacatecas, Unidad Academica de Fisica, 98000, Zacatecas, Zac. (Mexico); Rivera, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Alfaro C, M. R. [Centro de Investigacion en Materiales Avanzados, Alianza Norte 202, 66600 Apodaca, Nuevo Leon (Mexico); Vega C, H. R., E-mail: icearturoortiz@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, 98068 Zacatecas, Zac. (Mexico)

    2015-10-15

    Full text: In the last two decades, the search for new materials for dosimetry has included semiconductor nano materials because of their luminescent properties. This search has included the study, synthesis, characterization and performance of nano structured semiconductors, which optoelectronic properties determine their applications. In this paper the evolution of the thermoluminescent glow curve of nanocrystalline powder samples (40-70 nm) of zinc sulfide doped with manganese (Zn S:Mn) was analyzed at a dose of 500 Gy using a {sup 60}Co source. This material was synthesized by the coprecipitation method and heat treated at 500 degrees C in forming gas atmosphere (80 N{sub 2}:20H{sub 2}). Photoluminescence results indicate a direct relationship between the concentration of manganese and the intensity of a peak at λ ≅ 600 nm. By means of numerical deconvolution the behavior of the glow curves obtained at different times after exposure was analyzed. The causing traps of thermoluminescence are to 0.60 ± 0.05 and 1.7 ± 0.4 eV below the conduction band and within the band gap. The fading and a variation in the shape of the brightness curve (evolution) caused by non radiative transitions (rotational and vibrational) within the crystal structure of the material is also reported. (Author)

  1. γ射线暴火球模型的光学余辉辐射%Radiation mechanism of GRB optical after-glows

    Institute of Scientific and Technical Information of China (English)

    倪霓; 李若虹; 杨丕博

    2001-01-01

    According to the dynamics evolution rule of GRB in the model offireballs, and using the charactenistic of the spectra distribution of ultrarelative electron in magnetic field as well as the methord of the radiation in peak frequency, we calculate the variation of the R-band flux density of GRB after-glows with time, which is very consistent with observed spectra of GRB970028. Our result implys that synchrotron radiation is main mechanism of Gramma-ray bursts after-glows, and proves the validity of the model of fireballs.%按照γ射线暴火球模型的动力学演化规律,利用相对论电子在磁场中作同步加速辐射时谱分布的特点,用求峰值频率辐射的方法,计算了γ射线暴红光波段余辉辐射流量随时间的变化.与γ射线暴GRB970228的观测结果比较,符合甚好,说明同步加速辐射是γ射线暴余辉主要的辐射机制,也进一步证明了火球模型的正确.

  2. Food glowing with freshness

    Energy Technology Data Exchange (ETDEWEB)

    Desautels, L.

    1984-12-01

    Irradiation is gaining ground as a food preservation technique in Canada. Some fears remain among members of the public about the safety of irradiated foods, but government standards are being met. Two radiation sources can be used in food irradiation: gamma radiation from a cobalt 60 source, or electrons from an accelerator. The radiation affects the DNA of cells within food such as potatoes, preventing sprouting. It also causes changes within lipids, producing an undesirable rancid flavour. As a result, radiation processing is used primarily on fruits, vegetables, cereals and lean meats. The dose required for preservation is around 0.3 kGy, but higher doses are required for sterilization: 1 to 10 kGy, or even as high as 50 kGy for complete sterilization.

  3. The extraordinary glow

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Jinfeng, E-mail: liaoji@indiana.edu [Physics Department and Center for Exploration of Energy and Matter, Indiana University, 2401 N Milo B. Sampson Lane, Bloomington, IN 47408 (United States); RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2014-08-15

    In this contribution I discuss some recent progress in understanding the evolution of the pre-thermal quark–gluon matter, known as the glasma, during the early stage in heavy ion collisions, and the implication for early time photon and dilepton emissions.

  4. La proteína verde fluorescente ilumina la biociencia The Green Fluorescent Protein that glows in Bioscience

    Directory of Open Access Journals (Sweden)

    María Inés Pérez Millán

    2009-06-01

    related proteins, Drs. Shimomura, Chalfie and Tsien were awarded the Nobel Prize in Chemistry 2008. Dr. Shimomura discovered and studied the properties of GFP. Using molecular biological techniques, Chalfie succeeded in introducing the GFP gene into the DNA of the small, almost transparent worm C. elegans, and initiated an era in which GFP would be used as a glowing marker for cellular biology. Finally, Dr.Tsien found precisely how GFP's structure produces the observed green fluorescence, and succeeded in modifying the structure to generate molecules that emit light at slightly different wavelengths, which gave tags of different colors. Fluorescent proteins are very versatile and are being used in many areas, such as microbiology, biotechnology, physiology, environmental engineering, development, etc. They can, for example, illuminate growing cancer tumours; show the development of Alzheimer's disease, or detect arsenic traces in water. Finding the key to how a marine organism produces light unexpectedly ended up providing researchers with a powerful array of tools with which to visualize cell biology in action.

  5. Formation of Dielectric Barrier Multi-Pulse Glow Discharges in Helium at Atmospheric Pressure%大气压氦气介质阻挡多脉冲辉光放电的形成条件

    Institute of Scientific and Technical Information of China (English)

    郝艳捧; 王晓蕾; 阳林

    2009-01-01

    Discharge currents are measured on single pulse, multi-pulse glow dielectric barrier discharges (DBDs) using high-frequency power supply in helium at atmospheric pressure. The influence of the applied voltage amplitude and frequency, as well as gas distance on multi-pulse glow DBD is discussed and analyzed. Conditions to form multi-pulse glow DBDs are proposed. The results show that the higher amplitude of the applied voltage, the lower voltage frequency can be useful to form a multi-pulse glow DBD. Moreover, the higher applied voltage is necessary to form multi-pulse glow DBDs.%利用高频高压电源,进行大气压氦气介质阻挡放电试验,测量了单脉冲和多脉冲辉光放电的放电回路电流波形,分析了外加电压峰.峰值和频率、放电间隙对多脉冲辉光放电过程的影响,探讨了大气压氦气介质阻挡多脉冲辉光放电的形成条件.研究表明:多脉冲辉光放电的形成条件是较高的外加电压峰-峰值、较低的电源频率,其中较高的外加电压峰-峰值是产生多脉冲辉光放电的必要条件.

  6. Preparation and high-temperature oxidation behavior of plasma Cr-Ni alloying on Ti6Al4V alloy based on double glow plasma surface metallurgy technology

    Science.gov (United States)

    Wei, Dong-Bo; Zhang, Ping-Ze; Yao, Zheng-Jun; Wei, Xiang-Fei; Zhou, Jin-Tang; Chen, Xiao-Hu

    2016-12-01

    To improve the oxidation resistance of Ti6Al4V alloy, it was coated with a Cr-Ni alloy with 20, 40, 60, and 80 at.% Ni content using the double-glow plasma surface metallurgy technology. The coatings were dense, uniform, and compact, including a complete structure of deposited layer, interdiffusion layer, and sputtering-affected zone. The effect of Ni content on the isothermal oxidation behavior of coating was investigated at 750, 850, and 950 °C. The results show that the oxide scale consisted of NiO and Cr2O3. The morphology and distribution of NiO in oxide scale were affected by oxidation temperature and Ni content. When the Ni content was ≤40 at.%, the oxidation resistance of the Cr-Ni alloy coating was enhanced.

  7. Measurement of the equation of state and of the index of refraction of an amorphous glow discharge polymer up to 45 GPa

    Science.gov (United States)

    Plisson, Thomas; Colin-Lalu, Pierre; Huser, Gael; Loubeyre, Paul

    2016-08-01

    We present an experimental determination of the ambient temperature equation of state, P ( ρ / ρ 0 , 293 K ) , up to 45 GPa, of the glow discharge polymer (GDP) used as a confining capsule for the fusible deuterium-tritium mixture in inertial confinement fusion experiments. An original method has been implemented to measure both the compression factor and the refractive index versus pressure. The data are obtained in a diamond anvil cell with two sample chambers of equal thickness containing, respectively, the GDP and a NaCl reference. This experimental equation of state is compared to numerical first principles simulations. Deviations are ascribed to the difficulty to simulate the detailed atomic structure of the polymer under moderate pressure.

  8. 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.

  9. Degradation of Remazol Red in batik dye waste water by contact glow discharge electrolysis method using NaOH and NaCl electrolytes

    Science.gov (United States)

    Saksono, Nelson; Putri, Dita Amelia; Suminar, Dian Ratna

    2017-03-01

    Contact Glow Discharge Electrolysis (CGDE) method is one of Plasma Electrolysis technology which has been approved to degrade organic waste water because it is very productive in producing hydroxyl radical. This study aims to degrade Remazol Red by CGDE method and evaluate important parameters that have influent in degradation process of Remazol Red in Batik dye waste water in batch system. The kind of electrolyte (acid and base) and the addition of metal ion such as Fe2+ have affected Remazol Red degradation percentage. Ultraviolet-Visible (UV-Vis) absorption spectra were used to monitor the degradation process. The result of study showed that percentage degradation was 99.97% which obtained by using NaCl 0.02 M with addition Fe2+ 20 ppm, applied voltage 700 volt, anode depth 0.5 cm, initial concentration of Remazol Red 250 ppm and the temperature of solutions was maintained 50-60 ˚C.

  10. Application of contact glow discharge electrolysis method for degradation of batik dye waste Remazol Red by the addition of Fe2+ ion

    Science.gov (United States)

    Saksono, Nelson; Puspita, Indah; Sukreni, Tulus

    2017-03-01

    Contact Glow Discharge Electrolysis (CGDE) has been shown to degrade much weight organic compounds such as dyes because the production of hydroxil radical (•OH) is excess. This research aims to degrade batik dye waste Remazol Red, using CGDE method with the addition of Fe2+ ion. The addition of iron salt compounds has proven to increase process efficiency. Dye degradation is known by measure its absorbances with Spectrophotometer UV-Vis. The result of study showed that percentage degradation was 99.92% in 20 minutes which obtained by using Na2SO4 0.01 M, with addition FeSO4 0,1 gram, applied voltage 860 volt, and 1 wolfram anode 5 mm depth.

  11. 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.

  12. Investigation by techniques of electron stimulated desorption of the merits of glow discharge cleaning of the surfaces of vacuum chambers at the CERN intersecting storage rings

    CERN Document Server

    Jones, A W; Williams, E M

    1973-01-01

    To provide surface cleaning of the CERN intersecting storage rings, in which the pressure is below 10/sup -10/ torr over a 2 km length of mostly elliptical pipe (160*52 mm), ion bombardment during a glow discharge has been utilized. The discharge in argon at a pressure of about 3*10/sup -2/ torr was carried out intermittently in the course of a 15 h bake-out at 300 degrees C. Subsequent electron scrubbing enabled the electron desorption efficiency of the surface of the ISR vacuum chambers to be reduced by two to three orders of magnitude. Information is given on the apparatus used and the procedure adopted, together with a discussion of the diagnostic technique and a consideration of the action of the discharge cleaning. (15 refs).

  13. Liquid sampling-atmospheric pressure glow discharge (LS-APGD) ionization source for elemental mass spectrometry: preliminary parametric evaluation and figures of merit.

    Science.gov (United States)

    Quarles, C Derrick; Carado, Anthony J; Barinaga, Charles J; Koppenaal, David W; Marcus, R Kenneth

    2012-01-01

    A new, low-power ionization source for the elemental analysis of aqueous solutions has recently been described. The liquid sampling-atmospheric pressure glow discharge (LS-APGD) source operates at relatively low currents (LS-APGD has been interfaced to what is otherwise an organic, LC-MS mass analyzer, the Thermo Scientific Exactive Orbitrap without any modifications, other than removing the electrospray ionization source supplied with that instrument. A glow discharge is initiated between the surface of the test solution exiting a glass capillary and a metallic counter electrode mounted at a 90° angle and separated by a distance of ~5 mm. As with any plasma-based ionization source, there are key discharge operation and ion sampling parameters that affect the intensity and composition of the derived mass spectra, including signal-to-background ratios. We describe here a preliminary parametric evaluation of the roles of discharge current, solution flow rate, argon sheath gas flow rate, and ion sampling distance as they apply on this mass analyzer system. A cursive evaluation of potential matrix effects due to the presence of easily ionized elements indicate that sodium concentrations of up to 50 μg mL(-1) generally cause suppressions of less than 50%, dependant upon the analyte species. Based on the results of this series of studies, preliminary limits of detection (LOD) have been established through the generation of calibration functions. While solution-based concentration LOD levels of 0.02-2 μg mL(-1) are not impressive on the surface, the fact that they are determined via discrete 5 μL injections leads to mass-based detection limits at picogram to single-nanogram levels. The overhead costs associated with source operation (10 W d.c. power, solution flow rates of LS-APGD ion source may present a practical alternative to inductively coupled plasma sources typically employed in elemental mass spectrometry.

  14. The influence of dose on the kinetic parameters and dosimetric features of the main thermoluminescence glow peak in α-Al2O3:C,Mg

    Science.gov (United States)

    Kalita, J. M.; Chithambo, M. L.

    2017-03-01

    The influence of dose (0.1-100 Gy) on the kinetic parameters and the dosimetric features of the main glow peak of α-Al2O3:C,Mg have been investigated. Thermoluminescence (TL) measured at 1 °C/s shows a very high intensity glow peak at 161 °C and six secondary peaks at 42, 72, 193, 279, 330, 370 °C respectively. Analysis shows that the main peak follows first order kinetics irrespective of the irradiation dose. The activation energy is found to be consistent at 1.37 eV and the frequency factor is of the order of 1014 s-1 for any dose between 0.1 and 100 Gy. Further, the analysis for thermal quenching of the main peak of 0.1 Gy irradiated sample shows that the activation energy for thermal quenching is (0.94 ± 0.04) eV. Regarding the dosimetric features of α-Al2O3:C,Mg, the dose response of the main peak is superlinear within 0.1 to 30 Gy of beta dose and then it becomes sublinear up to 100 Gy. Fading analysis shows that the intensity of the main peak drops to ∼22% of its initial value within 2400 s after irradiation and thereafter to ∼14% within 64,800 s. Analysis of the reproducibility shows that the coefficient of variation in the results for 10 identical TL measurements show that reproducibility improves with increase in dose.

  15. Edge effect of DC glow discharge plasma%直流辉光等离子体的边缘效应

    Institute of Scientific and Technical Information of China (English)

    冯军; 陈美艳; 金凡亚; 但敏; 聂军伟; 沈丽如; 童洪辉; 赖新春

    2016-01-01

    结合辉光渗氮试验结果,对直流辉光等离子体材料处理中的边缘效应进行了研究,根据相关鞘层理论,对工件边角处及其附近的鞘层厚度S、电场强度E及离子密度n进行了定性分析。结果表明:在边缘效应范围d内,当远离边角时,S将变大、E及n变小。主等离子体密度n0的减少将使边缘效应的影响范围d变大,因此降低工作气压p及电流I可减弱边缘效应。采用改进措施渗氮后,工件边缘效应得到抑制,且渗氮效果较好。%Combined with the test results of glow discharge nitriding , edge effect of metals during DC glow discharge plasma treatment was investigated .According to the related theory of sheath , the sheath thickness S, electric field intensity E and ion density n in the corner of the work piece and its vicinity were analyzed qualitatively .The results show that the S increases, E and n decrease when far from the work piece edge in the edge effect range d.The decrease of the main plasma density n0 make the influence range d of the edge effect larger , thus lowering the working pressure p and the current I can weaken the edge effect .After nitriding by improved measures , the edge effect of the workpiece is suppressed , and the effect of nitriding is better .

  16. Mysteries of LiF TLD response following high ionisation density irradiation: nanodosimetry and track structure theory, dose response and glow curve shapes.

    Science.gov (United States)

    Horowitz, Y; Fuks, E; Datz, H; Oster, L; Livingstone, J; Rosenfeld, A

    2011-06-01

    Three outstanding effects of ionisation density on the thermoluminescence (TL) mechanisms giving rise to the glow peaks of LiF:Mg,Ti (TLD-100) are currently under investigation: (1) the dependence of the heavy charged particle (HCP) relative efficiency with increasing ionisation density and the effectiveness of its modelling by track structure theory (TST), (2) the behaviour of the TL efficiency, f(D), as a function of photon energy and dose. These studies are intended to promote the development of a firm theoretical basis for the evaluation of relative TL efficiencies to assist in their application in mixed radiation fields. And (3) the shape of composite peak 5 in the glow curve for various HCP types and energies and following high-dose electron irradiation, i.e. the ratio of the intensity of peak 5a to peak 5. Peak 5a is a low-temperature satellite of peak 5 arising from electron-hole capture in a spatially correlated trapping centre/luminescent centre (TC/LC) complex that has been suggested to possess a potential as a solid-state nanodosemeter due to the preferential electron/hole population of the TC/LC at high ionisation density. It is concluded that (1) the predictions of TST are very strongly dependent on the choice of photon energy used in the determination of f(D); (2) modified TST employing calculated values of f(D) at 2 keV is in agreement with 5-MeV alpha particle experimental results for composite peak 5 but underestimates the 1.5-MeV proton relative efficiencies. Both the proton and alpha particle relative TL efficiencies of the high-temperature TL (HTTL) peaks 7 and 8 are underestimated by an order of magnitude suggesting that the HTTL efficiencies are affected by other factors in addition to radial electron dose; (3) the dose-response supralinearity of peaks 7 and 8 change rapidly with photon energy: this behaviour is explained in the framework of the unified interaction model as due to a very strong dependence on photon energy of the relative

  17. 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.

  18. TREATMENT OF METALS, POLYMER FILMS, AND FABRICS WITH A ONE ATMOSPHERE UNIFORM GLOW DISCHARGE PLASMA (OAUGDP) FOR INCREASED SURFACE ENERGY AND DIRECTIONAL ETCHING

    Institute of Scientific and Technical Information of China (English)

    J. Reece Roth; Z.Y. Chen; Peter P.- Y. Tsai

    2001-01-01

    Direct exposure of samples to the active species of air generated by a One AtmosphereUniform Glow Discharge Plasma (OA UGDP) has been used to etch and to increasethe surface energy of metallic surfaces, photoresist, polymer films, and nonwoven fab-rics. The OAUGDP is a non-thermal plasma with the classical characteristics of aDC normal glow discharge that operates in air (and other gases) at atmospheric pres-sure. Neither a vacuum system nor batch processing is necessary. A wide range ofapplications to metals, photoresist, films, fabrics, and polymeric webs can be accom-modated by direct exposure of the workpiece to the plasma in parallel-plate reactors.This technology is simple, it produces effects that can be obtained in no other way atone atmosphere; it generates minimal pollutants or unwanted by-products; and it issuitable for individual sample or online treatment of metallic surfaces, wafers, films.and fabrics.``Early exposures of solid materials to the OA UGDP required minutes to produce rela-tively small increases of surface energy. These durations appeared too long for com-mercial application to fast-moving webs. Recent improvements in OA UGDP gas com-position, power density, plasma quality, recirculating gas flow, and impedance match-ing of the power supply to the parallel plate plasma reactor have made it possible toraise the surface energy ofa variety of polymeric webs (PP, PET, PE, etc.) to levels of60 to 70 dynes/crn with one second of exposure. In air plasmas, the high surface ener-gies are not durable, and fall to 50 dynes/em after periods of weeks to months. Here.we report the exposure of metallic surfaces, photoresist, polymeric films, and nonwo-ven fabrics made of PP and PET to an impedance matched parallel plate OA UGDPfor durations ranging from one second to several tens of seconds. Data will be re-ported on the surface energy, wettability, wickability, and aging effect of polymericfilms and fabrics as functions of time of exposure, and time

  19. Liquid Sampling-Atmospheric Pressure Glow Discharge (LS-APGD) Ionization Source for Elemental Mass Spectrometry: Preliminary Parametric Evaluation and Figures of Merit

    Energy Technology Data Exchange (ETDEWEB)

    Quarles, C. Derrick; Carado, Anthony J.; Barinaga, Charles J.; Koppenaal, David W.; Marcus, R. Kenneth

    2012-01-01

    A new, low power ionization source for the elemental analysis of aqueous solutions has recently been described. The liquid sampling-atmospheric pressure glow discharge (LS-APGD) source operates at relatively low currents (<20 mA) and solution flow rates (<50 μL min-1), yielding a relatively simple alternative for atomic mass spectrometry applications. The LS-APGD has been interfaced to what is otherwise an organic, LC-MS mass analyzer, the Thermo Scientific Exactive Orbitrap without any modifications; other than removing the electrospray ionization (ESI) source supplied with that instrument. A glow discharge is initiated between the surface of the test solution exiting a glass capillary and a metallic counter electrode mounted at a 90° angle and separated by a distance of ~5 mm. As with any plasma-based ionization source, there are key discharge operation and ion sampling parameters that affect the intensity and composition of the derived mass spectra; including signal-to-background ratios. We describe here a preliminary parametric evaluation of the roles of discharge current, solution flow rate, argon sheath gas flow rate, and ion sampling distance as they apply on this mass analyzer system. A cursive evaluation of potential matrix effects due to the presence of easily ionized elements (EIEs) indicate that sodium concentrations of up to 500 μg mL-1 generally cause suppressions of less than 50%, dependant upon the analyte species. Based on the results of this series of studies, preliminary limits of detection (LOD) have been established through the generation of calibration functions. Whilst solution-based concentrations LOD levels of 0.02 – 2 μg mL-1 3 are not impressive on the surface, the fact that they are determined via discrete 5 μL injections leads to mass-based detection limits at picogram to singlenanogram levels. The overhead costs associated with source operation (10 W d.c. power, solution flow rates of <50 μL min-1, and gas flow rates <10 mL min

  20. 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.

  1. Conversion of a micro, glow-ignition, two-stroke engine from nitromethane-methanol blend fuel to military jet propellant (JP-8)

    Science.gov (United States)

    Wiegand, Andrew L.

    The goal of the thesis "Conversion of a Micro, Glow-Ignition, Two-Stroke Engine from Nitromethane-Methanol Blend Fuel to Military Jet Propellant (JP-8)" was to demonstrate the ability to operate a small engine on JP-8 and was completed in two phases. The first phase included choosing, developing a test stand for, and baseline testing a nitromethane-methanol-fueled engine. The chosen engine was an 11.5 cc, glow-ignition, two-stroke engine designed for remote-controlled helicopters. A micro engine test stand was developed to load and motor the engine. Instrumentation specific to the low flow rates and high speeds of the micro engine was developed and used to document engine behavior. The second phase included converting the engine to operate on JP-8, completing JP-8-fueled steady-state testing, and comparing the performance of the JP-8-fueled engine to the nitromethane-methanol-fueled engine. The conversion was accomplished through a novel crankcase heating method; by heating the crankcase for an extended period of time, a flammable fuel-air mixture was generated in the crankcase scavenged engine, which greatly improved starting times. To aid in starting and steady-state operation, yttrium-zirconia impregnated resin (i.e. ceramic coating) was applied to the combustion surfaces. This also improved the starting times of the JP-8-fueled engine and ultimately allowed for a 34-second starting time. Finally, the steady-state data from both the nitromethane-methanol and JP-8-fueled micro engine were compared. The JP-8-fueled engine showed signs of increased engine friction while having higher indicated fuel conversion efficiency and a higher overall system efficiency. The minimal ability of JP-8 to cool the engine via evaporative effects, however, created the necessity of increased cooling air flow. The conclusion reached was that JP-8-fueled micro engines could be viable in application, but not without additional research being conducted on combustion phenomenon and

  2. Two-Dimensional Numerical Simulation of the DC Glow Discharge in the Normal Mode and with Einstein's Relation of Electron Diffusivity%Two-Dimensional Numerical Simulation of the DC Glow Discharge in the Normal Mode and with Einstein's Relation of Electron Diffusivity

    Institute of Scientific and Technical Information of China (English)

    A. BOUCHIKHI

    2012-01-01

    This paper presents an investigation of a DC glow discharge at low pressure in the normal mode and with Einstein's relation of electron diffusivity. Two-dimensional distributions in Cartesian geometry are presented in the stationary state, including electric potential, electron and ion densities, longitudinal and transverse electrics fields as well as electron temperature. Our results are compared with those obtained in existing literature. The model used in this work is based on the first three moments of Boltzmann's equation. They serve as the continuity equation, the momentum transfer and the energy equations. The set of equations for charged particles presented in monatomic argon gas are coupled in a self-consistent way with Poisson's equation. A parametric study varying the cathode voltage, gas pressure, and secondary electron emission coefficient predicts many of the well-known features of DC discharges.

  3. 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.

    2016-04-01

    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).

  4. Study On the Tribological Behavior of the Arc-added Glow Discharge Plasma Non-hydrogen Carburization On Titanium Alloy Surfaces

    Institute of Scientific and Technical Information of China (English)

    CHEN Fei; ZHAHGYue-fei; Liu Yu; TANG Bin; PAN Jun-de

    2004-01-01

    This paper introduces a new titanium alloys surface strengthening treatment by using the arc-added glow discharge plasmas non-hydrogen carburization technique. High purity and high strength graphite is selected as cooling cathode arc source for supplying carbon atoms and particle, which migrate to the titanium alloy(Ti6Al4V) surface and form modified layer. Thus, the hydrogen embrittlement is avoided while the tribological behavior of the titanium alloy surface is improved in the respects of anti-friction and anti-wear ability. The tribological behavior of the modified layer under dry sliding against SAE52100 steel was evaluated on a ball-on-disc test rig. The results showed that the modified layer obtained a thickness of 30μm at 980℃, 30minutes. The microhardness of the Ti6A14V alloy surface attained 936 HV, which was much larger than that of the Ti6A14V alloy. The Ti6A14V alloy was characterized by adhesion wear and scuffing under dry sliding against the steel, while the surface modified layer experienced much abated adhesion wear and scuffing under the same testing condition. This could be attributed to the carbon element with different modalities exists in the modified layer.The modified layer showed good friction-reducing and fair anti-wear ability in dry sliding against the steel. Using the SEM,XRD and XPS, the phase structure and morphology of the carburization modified layer was analyzed.

  5. The glow discharge inception and post-discharge relaxation of charged and neutral active particles in synthetic air at low pressure

    Science.gov (United States)

    Jovanović, A. P.; Marković, V. Lj; Stamenković, S. N.; Stankov, M. N.

    2015-11-01

    The study of dc glow discharge inception and post-discharge relaxation of charged and neutral active particles in synthetic air at low pressure is presented. The breakdown time delay dependence as a function of relaxation time \\overline{{{t}\\text{d}}}(τ ) (the memory curve) is measured and modelled from milliseconds to the saturation region determined by the cosmic rays and natural radioactivity level. Due to fast conversion \\text{N}2++{{\\text{O}}2}\\to {{\\text{N}}2}+\\text{O}2+ , relaxation of dc discharge in synthetic air in the time interval from one to about ninety milliseconds is dominated by the diffusion decay of molecular oxygen {{O}}_2^ + ions. The change of regimes, from ambipolar to the free diffusion limit, is investigated and the variation of effective diffusion coefficients is determined. The late relaxation is explained by the kinetics of nitrogen atoms, recombining on the surfaces of gas discharge tube and stainless steel electrodes and relevant surface recombination coefficients are determined.

  6. 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.

  7. Critical phenomena at a first-order phase transition in a lattice of glow lamps: Experimental findings and analogy to neural activity

    Science.gov (United States)

    Minati, Ludovico; de Candia, Antonio; Scarpetta, Silvia

    2016-07-01

    Networks of non-linear electronic oscillators have shown potential as physical models of neural dynamics. However, two properties of brain activity, namely, criticality and metastability, remain under-investigated with this approach. Here, we present a simple circuit that exhibits both phenomena. The apparatus consists of a two-dimensional square lattice of capacitively coupled glow (neon) lamps. The dynamics of lamp breakdown (flash) events are controlled by a DC voltage globally connected to all nodes via fixed resistors. Depending on this parameter, two phases having distinct event rate and degree of spatiotemporal order are observed. The transition between them is hysteretic, thus a first-order one, and it is possible to enter a metastability region, wherein, approaching a spinodal point, critical phenomena emerge. Avalanches of events occur according to power-law distributions having exponents ≈3/2 for size and ≈2 for duration, and fractal structure is evident as power-law scaling of the Fano factor. These critical exponents overlap observations in biological neural networks; hence, this circuit may have value as building block to realize corresponding physical models.

  8. Microstructure and corrosion resistance of Fe-Al intermetallic coating on 45 steel synthesized by double glow plasma surface alloying technology

    Institute of Scientific and Technical Information of China (English)

    ZHU Xiao-lin; YAO Zheng-jun; GU Xue-dong; CONG Wei; ZHANG Ping-ze

    2009-01-01

    A binary Fe-Al alloyed layer was synthesized on 45 steel by means of double glow plasma surface alloying technique. The corrosion-resisting layer prepared is composed of a sedimentary layer and a diffusion layer, with a total thickness of about 180 μm. The aluminum content of the alloyed layer shows gradual change from surface to the inside of substrate. The ideal profile is beneficial to the metallurgical bonding of the surface alloying layer with substrate materials. The microstructure of both layers consists of the Fe-Al intermetallic compound, which is FeAl with B2 structure in the sedimentary layer and Fe3Al with incompletely ordered DO3 structure in the diffusion layer. The protective film exhibits high micro-hardness. In comparison with the substrate of 45 steel, the corrosion resistance of the aluminized sample is much higher in 2.0% Na2S and 0.05 mol/L Na2SO4 + 0.5 mol/L NaCl mixed solutions.

  9. Tuneable microsecond-pulsed glow discharge design for the simultaneous acquisition of elemental and molecular chemical information using a time-of-flight mass spectrometer.

    Science.gov (United States)

    Solà-Vázquez, Auristela; Martín, Antonio; Costa-Fernández, José M; Pereiro, Rosario; Sanz-Medel, Alfredo

    2009-04-01

    A microsecond-pulsed direct current glow discharge (GD) was interfaced and synchronized to a time-of-flight mass spectrometer MS(TOF) for time-gated generation and detection of elemental, structural, and molecular ions. In this way, sequential collection of the mass spectra at different temporal regimes occurring during the GD pulse cycle is allowed. The capabilities of this setup were explored using bromochloromethane as model analyte. A simple GD chamber, developed in our laboratory and characterized by a low plasma volume minimizing dilution of the sample but showing great robustness to the entrance of organic compounds in the microsecond-pulsed plasma, has been used. An exhaustive analytical characterization of the GD-MS(TOF) prototype has been performed. Calibration curves for bromochloromethane observed at the different time regimes of the GD pulse cycle (that is, for elemental, fragment, and molecular ions from the analyte) showed very good linearity for the measurement of the different involved ions, with precisions in the range of 7-13% (relative standard deviation). Actual detection limits obtained for bromochloromethane were in the range of 1-3 microg/L for elements monitoring in the GD pulse "prepeak", in the range of 11-13 microg/L when monitoring analyte fragments in the plateau, and about 238 microg/L when measuring the molecular peak in the afterpeak regime.

  10. 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).

  11. Run-to-run variations, asymmetric pulses, and long time-scale transient phenomena in dielectric-barrier atmospheric pressure glow discharges

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jichul; Raja, Laxminarayan L [Department of Aerospace Engineering and Engineering Mechanics, University of Texas at Austin, Austin, TX 78712 (United States)

    2007-05-21

    The dielectric-barrier (DB) discharge is an important approach to generate uniform non-equilibrium atmospheric-pressure glow discharges. We report run-to-run variations, asymmetric pulse formation and long time-scale transient phenomena in these discharges. For similar DB discharge geometric and operating conditions, we observe significant run-to-run variations as manifested in the different voltage-current waveforms at the start of each new run. These run-to-run variations are also accompanied by asymmetric pulses at the start of each run. The variations are observed to drift to a repeatable true steady-state condition on time scales of order tens of minutes to hours. Asymmetric pulse waveforms drift to a symmetric pulse waveform at the true steady state. We explore reasons for these phenomena and rule out thermal drift during a discharge run and gas-phase impurity buildup as potential causes. The most plausible explanation appears to be variations in the surface characteristics of the DBs between two consecutive runs owing to varying inter-run environmental exposure and the conditioning of the dielectric surface during a run owing to plasma-surface interactions. We speculate that the dielectric surface state affects the secondary electron emission coefficient of the surface which in turn is manifested in the discharge properties. A zero-dimensional model of the discharge is used to explore the effect of secondary electron emission.

  12. Time-resolved measurement of emission profiles in pulsed radiofrequency glow discharge optical emission spectroscopy: Investigation of the pre-peak

    Energy Technology Data Exchange (ETDEWEB)

    Alberts, D. [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain); Horvath, P. [Swiss Federal Laboratories for Materials Testing and Research (EMPA), Feuerwerkerstrasse 39, 3602 Thun (Switzerland); Nelis, Th. [LAPLACE, Universite Paul Sabatier, 118 rte de Narbonne, Bat3R2, 31062 Toulouse Cedex (France); CU Jean Francois Champollion, Place de Verdun 81012 Albi Cedex 9 (France); Pereiro, R. [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain); Bordel, N. [Department of Physics, Faculty of Science, University of Oviedo, Calvo Sotelo, 33007 Oviedo (Spain); Michler, J. [Swiss Federal Laboratories for Materials Testing and Research (EMPA), Feuerwerkerstrasse 39, 3602 Thun (Switzerland); Sanz-Medel, A., E-mail: asm@uniovi.e [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain)

    2010-07-15

    Radiofrequency glow discharge coupled to optical emission spectroscopy has been used in pulsed mode in order to perform a detailed study of the measured temporal emission profiles for a wide range of copper transitions. Special attention has been paid to the early emission peak (or so-called pre-peak), observed at the beginning of the emission pulse profile. The effects of the important pulse parameters such as frequency, duty cycle, pulse width and power-off time, have been studied upon the Cu pulse emission profiles. The influence of discharge parameters, such as pressure and power, was studied as well. Results have shown that the intensity observed in the pre-peak can be 10 times as large as the plateau value for resonant lines and up to 5 times in case of transitions to the metastable levels. Increasing pressure or power increased the pre-peak intensity while its appearance in time changed. The pre-peak decreased when the discharge off-time was shorter than 100 {mu}s. According to such results, the presence of the pre-peak could be probably due to the lack of self-absorption during the first 50 {mu}s, and not to the ignition of the plasma. Under the selected operation conditions, the use of the pre-peak emission as analytical signals increases the linearity of calibration curves for resonant lines subjected to self-absorption at high concentrations.

  13. Determination of Hg(2+) by on-line separation and pre-concentration with atmospheric-pressure solution-cathode glow discharge atomic emission spectrometry.

    Science.gov (United States)

    Li, Qing; Zhang, Zhen; Wang, Zheng

    2014-10-03

    A simple and sensitive method to determine Hg(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(2+) elution conditions, namely, an FI flow rate of 2.0 mL min(-1) and an eluent comprised of 10% thiourea in 0.2 mol L(-1) HNO3. The detection limit of FI-SCGD-AES was determined to be 0.75 μg L(-1), and the precision of the 11 replicate Hg(2+) measurements was 0.86% at a concentration of 100 μg L(-1). The proposed method was validated by determining Hg(2+) in certified reference materials such as human hair (GBW09101b) and stream sediment (GBW07310).

  14. Measurement of the DC Stark shift for visible NeI lines and electric field distribution in the cathode sheath of an abnormal glow discharge

    Science.gov (United States)

    Ivanović, N. V.; Šišović, N. M.; Spasojević, Dj; Konjević, N.

    2017-03-01

    We present the results of an experimental study of the DC Stark shift for seven visible NeI lines in the plane cathode sheath region of an abnormal glow discharge operated in neon with a small admixture of hydrogen. The electric field (up to 13.4 kV cm‑1) in the cathode sheath region is measured from the π-polarized profile of the H alpha line of hydrogen using the Stark polarization spectroscopy technique. Within the realized range of the electric field, the NeI lines exhibit a quadratic Stark effect. The values of coefficients, correlating Stark shift and electric field strength, were determined, enabling their future use for unknown electric field strength measurements. Among the studied lines, so far only the Stark effect analysis of the NeI 511.367 nm line has been reported, in which case our results are in good agreement with the best fit formula proposed by Jäger and Windholz (1984 Phys. Scr. 29 344) for one out of three Stark components detected under our experimental conditions.

  15. Characterization of tantalum films on analytical surfaces: Insights into sputtering of nonconductors in a direct-current glow discharge using secondary cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Wayne, David M.; Havrilla, George [Nuclear Materials Technology Division, Analytical Chemistry, NMT-1, MS G740, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] Schulze, Ronald K. [Nuclear Materials Technology Division, Materials Characterization, NMT-11, MS G730, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] Maggiore, Carl [Materials Science and Technology Division, Center for Materials Science, MST-10, MS K765, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] Cooke, D. Wayne [Materials Science and Technology Division, MST-8, MS E546, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    1999-03-01

    We performed glow discharge mass spectrometry (GDMS) analyses on several nonconducting ceramic materials: a glass microscope slide, Nd-doped yttrium aluminum garnet (Nd:YAG), potassium titanyl phosphate (KTP), and several National Institute of Standards and Technology (NIST) Standard Reference Materials (e.g., Trace Elements in Glass SRM 610 and SRM 612). The sputtering of the nonconductor in the GD source results in the formation of a circular sputter crater whose surface profile varies with changing conditions in the GD cell. Following GD analysis, examination of the sample surfaces within, and adjacent to, the sputter crater by micro-X-ray fluorescence (MXRF) and scanning electron microscopy (SEM) indicated that the sputter-deposited Ta film is nonuniform. In several samples, a sharp discontinuity is observable in both Ta concentration and average {ital Z}-number approximately 0.5 mm from the crater perimeter. This discontinuity probably corresponds to the physical contact between the Ta cathode and the nonconducting sample beneath. Rutherford backscattering spectrometry (RBS) was then used to characterize Ta film thickness for each of the materials. The data presented here indicate that both crater shape and film thickness are dependent on GD sputtering parameters and on the nature of the material being sputtered. {copyright} {ital 1999} {ital Society for Applied Spectroscopy}

  16. The back-diffusion effect of air on the discharge characteristics of atmospheric-pressure radio-frequency glow discharges using bare metal electrodes

    Science.gov (United States)

    Sun, Wen-Ting; Liang, Tian-Ran; Wang, Hua-Bo; Li, He-Ping; Bao, Cheng-Yu

    2007-05-01

    Radio-frequency (RF), atmospheric-pressure glow discharge (APGD) plasmas using bare metal electrodes have promising prospects in the fields of plasma-aided etching, deposition, surface treatment, disinfection, sterilization, etc. In this paper, the discharge characteristics, including the breakdown voltage and the discharge voltage for sustaining a stable and uniform α mode discharge of the RF APGD plasmas are presented. The experiments are conducted by placing the home-made planar-type plasma generator in ambient and in a vacuum chamber, respectively, with helium as the primary plasma-forming gas. When the discharge processes occur in ambient, particularly for the lower plasma-working gas flow rates, the experimental measurements show that it is the back-diffusion effect of air in atmosphere, instead of the flow rate of the gas, that results in the obvious decrease in the breakdown voltage with increasing plasma-working gas flow rate. Further studies on the discharge characteristics, e.g. the luminous structures, the concentrations and distributions of chemically active species in plasmas, with different plasma-working gases or gas mixtures need to be conducted in future work.

  17. The back-diffusion effect of air on the discharge characteristics of atmospheric-pressure radio-frequency glow discharges using bare metal electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Sun Wenting; Liang Tianran; Wang Huabo; Li Heping; Bao Chengyu [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)

    2007-05-15

    Radio-frequency (RF), atmospheric-pressure glow discharge (APGD) plasmas using bare metal electrodes have promising prospects in the fields of plasma-aided etching, deposition, surface treatment, disinfection, sterilization, etc. In this paper, the discharge characteristics, including the breakdown voltage and the discharge voltage for sustaining a stable and uniform {alpha} mode discharge of the RF APGD plasmas are presented. The experiments are conducted by placing the home-made planar-type plasma generator in ambient and in a vacuum chamber, respectively, with helium as the primary plasma-forming gas. When the discharge processes occur in ambient, particularly for the lower plasma-working gas flow rates, the experimental measurements show that it is the back-diffusion effect of air in atmosphere, instead of the flow rate of the gas, that results in the obvious decrease in the breakdown voltage with increasing plasma-working gas flow rate. Further studies on the discharge characteristics, e.g. the luminous structures, the concentrations and distributions of chemically active species in plasmas, with different plasma-working gases or gas mixtures need to be conducted in future work.

  18. Effect of particle size on activation energy and peak temperature of the thermoluminescence glow curve of undoped ZnS nanoparticles.

    Science.gov (United States)

    Chandra, B P; Chandrakar, Raju Kumar; Chandra, V K; Baghel, R N

    2016-03-01

    This paper reports the effect of particle size on the thermoluminescence (TL) of undoped ZnS nanoparticles. ZnS nanoparticles were prepared using a chemical precipitation method in which mercaptoethanol was used as the capping agent. The nanoparticles were characterized by X-ray diffraction, field emission gun-scanning electron microscopy and high-resolution transmission electron microscopy. When the concentrations of mercaptoethanol used are 0, 0.005, 0.01, 0.015, 0.025, 0.040 and 0.060 M, the sizes of the nanoparticles are 2.86, 2.81, 2.69, 2.40, 2.10, 1.90 and 1.80 nm, respectively. Initially, the TL intensity of UV-irradiated ZnS nanoparticles increases with temperature, attains a peak value Im for a particular temperature Tm, and then decreases with further increases in temperature. The values of both Im and Tm increase with decreasing nanoparticle size. Whereas the activation energy decreases slightly with decreasing nanoparticle size, the frequency factor decreases significantly as the nanoparticle size is reduced. The order of kinetics for the TL glow curve of ZnS nanoparticles is 2. Expressions are derived for the dependence of activation energy (Ea) and Tm on nanoparticle size, and good agreement is found between the experimental and theoretical results.

  19. Development of open-air type electrolyte-as-cathode glow discharge-atomic emission spectrometry for determination of trace metals in water

    Science.gov (United States)

    Kim, Hyo J.; Lee, Jeong H.; Kim, Myung Y.; Cserfalvi, T.; Mezei, P.

    2000-07-01

    The open-air type electrolyte cathode atomic glow discharge (ELCAD) has been developed and studied for fundamental and analytical applications for determination of trace heavy metals in water. The normal closed-type discharge cell shows some problems such as unstable plasma due to changes in the pressure inside the cell during the discharge, and water vapor condensing onto the window. Applying approximately 1500 V to the several-millimeter gap between the electrolyte solution cathode and a Pt rod anode in atmospheric air pressure produced a stable plasma and significantly improved sensitivity. The emission spectrum of de-ionized water containing 100 mg/l Cu was measured and some emission lines were found from Cu I (324.7 nm, 327.4 nm and 510.5 nm) and Cu II (224.7 nm and 229.4 nm). The LODs of Cr, Cu, Fe, Mn, Ni, Pb, and Zn are in the ranges from 0.01 mg/l to 0.6 mg/l. The LODs of Cu, Mn, Pb and Zn improve by approximately one order of magnitude compared to the previous closed-type ELCAD.

  20. Poly (Acrylamide-co-Acrylic Acid) Hydrogel Induced by Glow-Discharge Electrolysis Plasma and Its Adsorption Properties for Cationic Dyes

    Science.gov (United States)

    Yu, Jie; Yang, Gege; Pan, Yuanpei; Lu, Quanfang; Yang, Wu; Gao, Jinzhang

    2014-08-01

    In this paper, poly (acrylamide-co-acrylic acid) (P(AM-co-AA)) hydrogel was prepared in an aqueous solution by using glow-discharge electrolysis plasma (GDEP) induced copolymerization of acrylamide (AM) and acrylic acid (AA), in which N,N'-methylenebisacrylamide (MBA) was used as a crosslinker. A mechanism for the synthesis of P(AM-co-AA) hydrogel was proposed. To optimize the synthesis condition, the following parameters were examined in detail: the discharge voltage, discharge time, the content of the crosslinker, and the mass ratio of AM to AA. The results showed that the optimum pH range for cationic dyes removal was found to be 5.0-10.0. The P(AM-co-AA) hydrogel exhibits a very high adsorption potential and the experimental adsorption capacities for Crystal violet (CV) and Methylene blue (MB) were 2974.3 mg/g and 2303.6 mg/g, respectively. The adsorption process follows a pseudo-second-order kinetic model. In addition, the adsorption mechanism of P(AM-co-AA) hydrogel for cationic dyes was also discussed.

  1. 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.

  2. 接触辉光放电等离子体处理有机砷废水%Treatment of organoarsenic wastewater using contact glow discharge plasma

    Institute of Scientific and Technical Information of China (English)

    胡平; 郑星; 刘玉坤; 郭建波; 李素娟; 郑经堂

    2016-01-01

    Organoarsenic compounds,such as roxarsone (ROX),are extensively used as feed additives in the agricultural industry,and have become a serious environmental concern.This study investigated unprecedentedly the applicability of the contact glow discharge process (CGDP) for ROX oxidation and degradation in aqueous solution,and evaluated the effects of various reaction conditions on ROX conversion.The results indicated that ROX could be completely degraded,with As(Ⅴ) as the final product.The higher energy input was beneficial for a higher As(Ⅴ) production efficiency,whereas the solution pH did not seem to influence the ROX oxidation efficiency.Consequently,approximately 97% of ROX degraded,and more than 95 μmol · L-1 As(Ⅴ) were generated within 42 min under the optimum glow discharge condition (58 W of input energy,pH 4.0).Furthermore,addition of Fe(Ⅱ) into the CGDP system significantly enhanced the ROX oxidation,due to the consumption of in-situ electrogenerated H2O2 in CGDP and the generation of additional-OH.Furthermore,the experiments of quenching active radicals indicated that · OH plays an important role in the mineralization of ROX to arsenate,and also confirmed the ROX degradation mechanism in the CGDP system.%洛克沙砷(ROX)饲料添加剂在农业的普遍使用,导致大量的ROX进入自然水体,引起环境污染.为了修复含ROX废水,首次提出采用接触辉光放电等离子体(CGDP)氧化ROX,并考察了多种因素对ROX降解效果的影响.结果表明,ROX能被CGDP完全氧化降解,且As(Ⅴ)是其最终降解产物;输入能量的增加利于ROX的氧化,而pH值对ROX的降解影响较小;在辉光放电最佳条件(输入能量58 W,pH 4.O)下,加入100 μmol·L-1ROX,42 min内降解率为97%,As(Ⅴ)的生成量可达95 μmol·L-1.此外,加入一定量的Fe(Ⅱ),因其可以通过利用CGDP原位产生的H2O2通过芬顿反应产生大量额外的·OH,而能显著地催化ROX转化为无机砷.通过自由基捕获实验,

  3. When, where and how osteoporosis-associated fractures occur: an analysis from the Global Longitudinal Study of Osteoporosis in Women (GLOW.

    Directory of Open Access Journals (Sweden)

    Aline G Costa

    Full Text Available To examine when, where and how fractures occur in postmenopausal women.We analyzed data from the Global Longitudinal Study of Osteoporosis in Women (GLOW, including women aged ≥55 years from the United States of America, Canada, Australia and seven European countries. Women completed questionnaires including fracture data at baseline and years 1, 2 and 3.Among 60,393 postmenopausal women, 4122 incident fractures were reported (86% non-hip, non-vertebral [NHNV], 8% presumably clinical vertebral and 6% hip. Hip fractures were more likely to occur in spring, with little seasonal variation for NHNV or spine fractures. Hip fractures occurred equally inside or outside the home, whereas 65% of NHNV fractures occurred outside and 61% of vertebral fractures occurred inside the home. Falls preceded 68-86% of NHNV and 68-83% of hip fractures among women aged ≤64 to ≥85 years, increasing with age. About 45% of vertebral fractures were associated with falls in all age groups except those ≥85 years, when only 24% occurred after falling.In this multi-national cohort, fractures occurred throughout the year, with only hip fracture having a seasonal variation, with a higher proportion in spring. Hip fractures occurred equally within and outside the home, spine fractures more often in the home, and NHNV fractures outside the home. Falls were a proximate cause of most hip and NHNV fractures. Postmenopausal women at risk for fracture need counseling about reducing potentially modifiable fracture risk factors, particularly falls both inside and outside the home and during all seasons of the year.

  4. 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

  5. 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)

  6. Preliminary Figures of Merit for Isotope Ratio Measurements: The Liquid Sampling-Atmospheric Pressure Glow Discharge Microplasma Ionization Source Coupled to an Orbitrap Mass Analyzer.

    Science.gov (United States)

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

    2016-08-01

    In order to meet a growing need for fieldable mass spectrometer systems for precise elemental and isotopic analyses, the liquid sampling-atmospheric pressure glow discharge (LS-APGD) has a number of very promising characteristics. One key set of attributes that await validation deals with the performance characteristics relative to isotope ratio precision and accuracy. Owing to its availability and prior experience with this research team, the initial evaluation of isotope ratio (IR) performance was performed on a Thermo Scientific Exactive Orbitrap instrument. While the mass accuracy and resolution performance for Orbitrap analyzers are well-documented, no detailed evaluations of the IR performance have been published. Efforts described here involve two variables: the inherent IR precision and accuracy delivered by the LS-APGD microplasma and the inherent IR measurement qualities of Orbitrap analyzers. Important to the IR performance, the various operating parameters of the Orbitrap sampling interface, high-energy collisional dissociation (HCD) stage, and ion injection/data acquisition have been evaluated. The IR performance for a range of other elements, including natural, depleted, and enriched uranium isotopes was determined. In all cases, the precision and accuracy are degraded when measuring low abundance (<0.1% isotope fractions). In the best case, IR precision on the order of 0.1% RSD can be achieved, with values of 1%-3% RSD observed for low-abundance species. The results suggest that the LS-APGD is a promising candidate for field deployable MS analysis and that the high resolving powers of the Orbitrap may be complemented with a here-to-fore unknown capacity to deliver high-precision IRs. Graphical Abstract ᅟ.

  7. Preliminary Figures of Merit for Isotope Ratio Measurements: The Liquid Sampling-Atmospheric Pressure Glow Discharge Microplasma Ionization 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

    2016-03-01

    ABSTRACT In order to meet a growing need for fieldable mass spectrometer systems for precise elemental and isotopic analyses, the liquid sampling-atmospheric pressure glow discharge (LS-APGD) has a number of very promising characteristics. One key set of attributes that await validation deals with the performance characteristics relative to isotope ratio precision and accuracy. Due to its availability and prior experience with this research team, the initial evaluation of isotope ratio (IR) performance was performed on a Thermo Scientific Exactive Orbitrap instrument. While the mass accuracy and resolution performance for orbitrap analyzers are very well documented, no detailed evaluations of the IR performance have been published. Efforts described here involve two variables: the inherent IR precision and accuracy delivered by the LSAPGD microplasma and the inherent IR measurement qualities of orbitrap analyzers. Important to the IR performance, the various operating parameters of the orbitrap sampling interface, HCD dissociation stage, and ion injection/data acquisition have been evaluated. The IR performance for a range of other elements, including natural, depleted, and enriched uranium isotopes was determined. In all cases the precision and accuracy are degraded when measuring low abundance (<0.1% isotope fractions). In the best case, IR precision on the order of 0.1 %RSD can be achieved, with values of 1-3 %RSD observed for low-abundance species. The results suggest that the LSAPGD is a very good candidate for field deployable MS analysis and that the high resolving powers of the orbitrap may be complemented with a here-to-fore unknown capacity to deliver high-precision isotope ratios.

  8. The influence of stabilizers on the production of gold nanoparticles by direct current atmospheric pressure glow microdischarge generated in contact with liquid flowing cathode

    Energy Technology Data Exchange (ETDEWEB)

    Dzimitrowicz, Anna; Jamroz, Piotr, E-mail: piotr.jamroz@pwr.edu.pl; Greda, Krzysztof; Nowak, Piotr; Nyk, Marcin; Pohl, Pawel [Wroclaw University of Technology, Faculty of Chemistry (Poland)

    2015-04-15

    Gold nanoparticles (Au NPs) were prepared by direct current atmospheric pressure glow microdischarge (dc-μAPGD) generated between a miniature argon flow microjet and a flowing liquid cathode. The applied discharge system was operated in a continuous flow liquid mode. The influence of various stabilizers added to the solution of the liquid cathode, i.e., gelatin (GEL), polyvinylpyrrolidone (PVP), or polyvinyl alcohol (PVA), as well as the concentration of the Au precursor (chloroauric acid, HAuCl{sub 4}) in the solution on the production growth of Au NPs was investigated. Changes in the intensity of the localized surface plasmon resonance (LSPR) band in UV/Vis absorption spectra of solutions treated by dc-μAPGD and their color were observed. The position and the intensity of the LSPR band indicated that relatively small nanoparticles were formed in solutions containing GEL as a capping agent. In these conditions, the maximum of the absorption LSPR band was at 531, 534, and 535 nm, respectively, for 50, 100, and 200 mg L{sup −1} of Au. Additionally, scanning electron microscopy (SEM) and dynamic light scattering (DLS) were used to analyze the structure and the morphology of obtained Au NPs. The shape of Au NPs was spherical and uniform. Their mean size was ca. 27, 73, and 92 nm, while the polydispersity index was 0.296, 0.348, and 0.456 for Au present in the solution of the flowing liquid cathode at a concentration of 50, 100, and 200 mg L{sup −1}, respectively. The production rate of synthesized Au NPs depended on the precursor concentration with mean values of 2.9, 3.5, and 5.7 mg h{sup −1}, respectively.

  9. Preliminary Figures of Merit for Isotope Ratio Measurements: The Liquid Sampling-Atmospheric Pressure Glow Discharge Microplasma Ionization Source Coupled to an Orbitrap Mass Analyzer

    Science.gov (United States)

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

    2016-08-01

    In order to meet a growing need for fieldable mass spectrometer systems for precise elemental and isotopic analyses, the liquid sampling-atmospheric pressure glow discharge (LS-APGD) has a number of very promising characteristics. One key set of attributes that await validation deals with the performance characteristics relative to isotope ratio precision and accuracy. Owing to its availability and prior experience with this research team, the initial evaluation of isotope ratio (IR) performance was performed on a Thermo Scientific Exactive Orbitrap instrument. While the mass accuracy and resolution performance for Orbitrap analyzers are well-documented, no detailed evaluations of the IR performance have been published. Efforts described here involve two variables: the inherent IR precision and accuracy delivered by the LS-APGD microplasma and the inherent IR measurement qualities of Orbitrap analyzers. Important to the IR performance, the various operating parameters of the Orbitrap sampling interface, high-energy collisional dissociation (HCD) stage, and ion injection/data acquisition have been evaluated. The IR performance for a range of other elements, including natural, depleted, and enriched uranium isotopes was determined. In all cases, the precision and accuracy are degraded when measuring low abundance (<0.1% isotope fractions). In the best case, IR precision on the order of 0.1% RSD can be achieved, with values of 1%-3% RSD observed for low-abundance species. The results suggest that the LS-APGD is a promising candidate for field deployable MS analysis and that the high resolving powers of the Orbitrap may be complemented with a here-to-fore unknown capacity to deliver high-precision IRs.

  10. Preliminary Assessment of Potential for Metal-Ligand Speciation in Aqueous Solution via the Liquid Sampling-Atmospheric Pressure Glow Discharge (LS-APGD) Ionization Source: Uranyl Acetate.

    Science.gov (United States)

    Zhang, Lynn X; Manard, Benjamin T; Powell, Brian A; Marcus, R Kenneth

    2015-07-21

    The determination of metals, including the generation of metal-ligand speciation information, is essential across a myriad of biochemical, environmental, and industrial systems. Metal speciation is generally affected by the combination of some form of chromatographic separation (reflective of the metal-ligand chemistry) with element-specific detection for the quantification of the metal composing the chromatographic eluent. Thus, the identity of the metal-ligand is assigned by inference. Presented here, the liquid sampling-atmospheric pressure glow discharge (LS-APGD) is assessed as an ionization source for metal speciation, with the uranyl ion-acetate system used as a test system. Molecular mass spectra can be obtained from the same source by simple modification of the sustaining electrolyte solution. Specifically, chemical information pertaining to the degree of acetate complexation of uranyl ion (UO2(2+)) is assessed as a function of pH in the spectral abundance of three metallic species: inorganic (nonligated) uranyl, UO2Ac(H2O)n(MeOH)m(+), and UO2Ac2(H2O)n(MeOH)(m)H(+) (n = 1, 2, 3, ...; m = 1, 2, 3, ...). The product mass spectra are different from what are obtained from electrospray ionization sources that have been applied to this system. The resulting relationships between the speciation and pH values have been compared to calculated concentrations of the corresponding uranyl species: UO2(2+), UO2Ac(+), UO2Ac2. The capacity for the LS-APGD to affect both atomic mass spectra and structurally significant spectra for organometallic complexes is a unique and potentially powerful combination.

  11. Evaluation of the operating parameters of the liquid sampling-atmospheric pressure glow discharge (LS-APGD) ionization source for elemental mass spectrometry.

    Science.gov (United States)

    Zhang, Lynn X; Manard, Benjamin T; Konegger-Kappel, Stefanie; Kappel, Stefanie Konegger; Marcus, R Kenneth

    2014-11-01

    The liquid sampling-atmospheric pressure glow discharge (LS-APGD) has been assessed as an ionization source for elemental analysis with an interdependent, parametric evaluation regarding sheath/cooling gas flow rate, discharge current, liquid flow rate, and the distance between the plasma and the sampling cone of the mass spectrometer. In order to better understand plasma processes (and different from previous reports), no form of collision/reaction processing was performed to remove molecular interferents. The evaluation was performed employing five test elements: cesium, silver, lead, lanthanum and nickel (10(-4) mol L(-1) in 1 mol L(-1) HNO3). The intensity of the atomic ions, levels of spectral background, the signal-to-background ratios, and the atomic-to-oxide/hydroxide adduct ratios were monitored in order to obtain fundamental understanding with regards to not only how each parameter effects the performance of this LS-APGD source, but also the inter-parametric effects. The results indicate that the discharge current and the liquid sampling flow rates are the key aspects that control the spectral composition. A compromise set of operating conditions was determined: sheath gas flow rate = 0.9 L min(-1), discharge current = 10 mA, solution flow rate = 10 μL min(-1), and sampling distance = 1 cm. Limits of detection (LODs) were calculated using the SBR-RSDB (signal-to-background ratio/relative standard deviation of the background) approach under the optimized condition. The LODs for the test elementals ranged from 15 to 400 ng mL(-1) for 10 μL injections, with absolute mass values from 0.2 to 4 ng.

  12. Influence of operating parameters on surface properties of RF glow discharge oxygen plasma treated TiO₂/PET film for biomedical application.

    Science.gov (United States)

    Pandiyaraj, K Navaneetha; Deshmukh, R R; Mahendiran, R; Su, Pi-G; Yassitepe, Emre; Shah, Ismat; Perni, Stefano; Prokopovich, Polina; Nadagouda, Mallikarjuna N

    2014-03-01

    In this paper, a thin transparent titania (TiO2) film was coated on the surface of flexible poly(ethylene terephthalate) (PET) film using the sol-gel method. The surface properties of the obtained TiO2/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 TiO2/PET films were analyzed by contact angle measurements and surface energy. The influence of plasma on the surface of the TiO2/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 TiO2/PET films was analyzed using human osteoblast cells and the bacterial eradication behaviors of TiO2/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 TiO2/PET films increased substantially as compared to the untreated one. Moreover the increased concentration of Ti(3+) on the surface of plasma treated TiO2/PET films was due to the transformation of chemical states (Ti(4+)→Ti(3+)). These morphological and chemical changes are responsible for enhanced hydrophilicity of the TiO2/PET films. Furthermore, the plasma treated TiO2/PET film exhibited no citotoxicity against osteoblast cells and antibacterial activity against Staphylococcus bacteria which can find application in manufacturing of biomedical devices.

  13. From hot rocks to glowing avalanches: Numerical modelling of gravity-induced pyroclastic density currents and hazard maps at the Stromboli volcano (Italy)

    Science.gov (United States)

    Salvatici, Teresa; Di Roberto, Alessio; Di Traglia, Federico; Bisson, Marina; Morelli, Stefano; Fidolini, Francesco; Bertagnini, Antonella; Pompilio, Massimo; Hungr, Oldrich; Casagli, Nicola

    2016-11-01

    Gravity-induced pyroclastic density currents (PDCs) can be produced by the collapse of volcanic crater rims or due to the gravitational instability of materials deposited in proximal areas during explosive activity. These types of PDCs, which are also known as "glowing avalanches", have been directly observed, and their deposits have been widely identified on the flanks of several volcanoes that are fed by mafic to intermediate magmas. In this research, the suitability of landslide numerical models for simulating gravity-induced PDCs to provide hazard assessments was tested. This work also presents the results of a back-analysis of three events that occurred in 1906, 1930 and 1944 at the Stromboli volcano by applying a depth-averaged 3D numerical code named DAN-3D. The model assumes a frictional internal rheology and a variable basal rheology (i.e., frictional, Voellmy and plastic). The numerical modelling was able to reproduce the gravity-induced PDCs' extension and deposit thicknesses to an order of magnitude of that reported in the literature. The best results when compared with field data were obtained using a Voellmy model with a frictional coefficient of f = 0.19 and a turbulence parameter ξ = 1000 m s- 1. The results highlight the suitability of this numerical code, which is generally used for landslides, to reproduce the destructive potential of these events in volcanic environments and to obtain information on hazards connected with explosive-related, mass-wasting phenomena in Stromboli Island and at volcanic systems characterized by similar phenomena.

  14. 针-板DBD微流注与微辉光交替生成的机理研究%Atmospheric pressure streamer and glow-discharge generated alternately by pin-to-plane dielectric barrier discharge in air

    Institute of Scientific and Technical Information of China (English)

    俞哲; 张芝涛; 于清旋; 许少杰; 姚京; 白敏冬; 田一平; 刘开颖

    2012-01-01

    Performance of producing a high energy electron can be improved, if the glow discharge is generated in a system of dielectric barrier discharge. In this paper, different discharge modes of pin-to-plane dielectric barrier discharge are investigated in atmospheric pressure. Different discharge modes are observed in the positive half-period and negative half-period of the discharge. When and applied voltage is 3 kV, a streamer mode appear in the positive half-period and a corona (or Trichel discharge) mode occurs in negative half-period. When the applied voltage is 6 kV, a streamer emerges in the positive half-period and a micro glow discharge is present in the negative half-period. The micro glow discharge has hierarchical structure like that typical low pressure glow discharge produces. The generation of micro glow discharge is due to, enough strong cathode electric field strength and effective secondary electron emission process around naked negative electrode. The glow discharge transforming to arc discharge is avoided due to dielectric layer.%在介质阻挡放电体系中产生辉光放电可以有效的提高放电体系产生高能电子的性能,为等离子体化学反应提供更加丰富的活性粒子.本文对针一板介质阻挡放电体系下的放电模式进行了研究,实验发现放电正负半周期表现出不同的放电模式,激励电压为3kV时放电正负半周期分别为微流注放电和电晕放电(或者Trichel脉冲放电),激励电压为6kV时放电正负半周期分别为微流注放电和微辉光放电.微辉光放电形貌具有与典型辉光放电相同的分层次放电结构,分析了激励电压6kV时的放电过程,认为足够强的阴极电场强度和裸露针状电极形成的有效的二次电子发射过程是形成微辉光放电的主要因素,绝缘介质层的存在避免了微辉光放电向弧光放电过渡.

  15. Study of IR Property of Glow Discharge Polymer (GDP)%辉光放电聚合物薄膜的红外性质研究

    Institute of Scientific and Technical Information of China (English)

    温成伟; 尹剑; 余铭铭; 李海容; 夏立东; 何智兵; 梁建华

    2016-01-01

    为了实现惯性约束聚变(IC F )点火,需要制备出均匀的高密度燃料靶。对于氘氘(DD )冰层,红外均化技术可用于改善其内表面粗糙度。本文利用红外光谱仪和红外显微镜研究了辉光放电聚合物(GDP)薄膜和靶球的红外吸收性质,得到了GDP薄膜材料特定波长处的红外吸收系数。通过比较薄膜材料和靶球的红外吸收,证实了热处理可以降低GDP材料中的氧化位点,从而抑制羟基(—O H )峰的形成,优化DD冰层的红外均化效果。利用所得实验数据对DD均化实验中红外均化积分球所需要的红外功率和国家点火装置(national ignition facility ,NIF)标准靶的红外透射率进行了估算,计算结果对DD冰红外均化实验具有重要指导作用。%To achieve the object of NIF ignition ,it is required to prepare high density fuel targets .For DD layer ,IR‐layering can be used to improve its surface roughness .In this paper ,glow discharge polymer (GDP) flat films and capsules were synthe‐sized .The IR absorptive properties of GDP were thoroughly studied by using infrared spectrometer and microscopy while the ex‐tinction coefficients of GDP flat film at specific wavelengths were obtained .By comparing absorption properties of flat films and capsules ,it is found that thermal treatments can lower the OH content of GDP and thus improve IR layering of DD ice .Finally , the needed IR power of integration sphere were estimated by using data obtained for future DD layering experiments in this pa‐per .The results have laid a solid foundation for the implementation of DD IR layering .

  16. 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.

  17. Measuring the color and brightness of artificial sky glow from cities using an all-sky imaging system calibrated with astronomical methods in the Johnson-Cousins B and V photometric systems

    Science.gov (United States)

    Pipkin, Ashley; Duriscoe, Dan M.; Lughinbuhl, Christian

    2017-01-01

    Artificial light at night, when observed at some distance from a city, results in a dome of sky glow, brightest at the horizon. The spectral power distribution of electric light utilized will determine its color of the light dome and the amount of light will determine its brightness. Recent outdoor lighting technologies have included blue-rich light emitting diode (LED) sources that may increase the relative amount of blue to green light in sky glow compared to typical high pressure sodium (HPS) sources with warmer spectra. Measuring and monitoring this effect is important to the preservation of night sky visual quality as seen from undeveloped areas outside the city, such as parks or other protected areas, since the dark-adapted human eye is more sensitive to blue and green. We present a method using a wide field CCD camera which images the entire sky in both Johnson V and B photometric bands. Standard stars within the images are used for calibration. The resulting all-sky brightness maps, and a derived B-V color index map, provide a means to assess and track the impact of specific outdoor lighting practices. We also present example data from several cities, including Las Vegas, Nevada, Flagstaff, Arizona, and Cheyenne, Wyoming.

  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.

  19. Why Do Proteins Glow Blue?

    CERN Document Server

    Sarkar, Sohini; Hazra, Partha; Mandal, Pankaj

    2014-01-01

    Recent literatures reported blue-green emission from amyloid fibril as exclusive signature of fibril formation. This unusual visible luminescence is regularly used to monitor fibril growth. Blue-green emission has also been observed in crystalline protein and in solution. However, the origin of this emission is not known exactly. Our spectroscopic study of serum proteins reveals that the blue-green emission is a property of protein monomer. Evidences suggest that semiconductor-like band structure of proteins with the optical band-gap in the visible region is possibly the origin of this phenomenon. We show here that the band structure of proteins is primarily the result of electron delocalization through the peptide chain, rather than through the hydrogen bond network in secondary structure.

  20. Neutron-photon mixed field dosimetry by TLD-700 glow curve analysis and its implementation in dose monitoring for Boron Neutron Capture Therapy (BNCT) treatments

    Energy Technology Data Exchange (ETDEWEB)

    Boggio, E. F.; Longhino, J. M. [Centro Atomico Bariloche, Departamento de Fisica de Reactores y Radiaciones / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina); Andres, P. A., E-mail: efboggio@cab.cnea.gov.ar [Centro Atomico Bariloche, Division Proteccion Radiologica / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina)

    2015-10-15

    BNCT is a cancerous cells selective, non-conventional radiotherapy modality to treat malignant tumors such as glioblastoma, melanoma and recurrent head and neck cancer. It consists of a two-step procedure: first, the patient is injected with a tumor localizing drug containing a non-radioactive isotope (Boron-10) with high slow neutron capture cross-section. In a second step, the patient is irradiated with neutrons, which are absorbed by the Boron-10 agent with the subsequently nuclear reaction B- 10(n,a)Li-7, thereby resulting in dose at cellular level due to the high-Let particles. The neutron fields suitable for BNCT are characterized by high neutron fluxes and low gamma dose. Determination of each component is not an easy task, especially when the volume of measurement is quite small or inaccessible for a miniature ionization chamber, for example. A method of measuring the photon and slow neutron dose(mainly by N-14 and B-10) from the glow curve (GC) analysis of a single {sup 7}LiF thermoluminescence detector is evaluated. This method was suggested by the group headed by Dr. Grazia Gambarini. The dosemeters used were TLD-600 ({sup 6}LiF:Mg,Ti with 95.6% {sup 6}Li) and TLD-700 ({sup 7}LiF:Mg,Ti with 99.9% {sup 7}LiF) from Harshaw. Photon dose measurement using the GC analysis method with TLD-700 in mixed fields requires the relation of the two main peaks of a TLD-600 GC shape obtained from an exposition to the same neutron field, and a photon calibrated GC with TLD-700. The requirements for slow neutron dose measurements are similar. In order to properly apply the GC analysis method at the Ra-6 Research Reactor BNCT facility, measurements were carried out in a standard water phantom, fully characterized on the BNCT beam by conventional techniques (activation detectors and paired ionization chambers technique). Next, the method was implemented in whole body dose monitoring of a patient undergoing a BNCT treatment, using a Bo MAb (Bottle Manikin Absorption) phantom

  1. Degradation of Inorganic Dyes Direct Black EX in Wastewater Using Glow Discharge Plasma%辉光放电等离子体处理有机染料直接黑EX废水

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      辉光放电电解是一种新型的产生等离子体的电化学方法。在惰性电解质水溶液中进行辉光放电电解,可以产生大量的·OH、·H、e-aq、HO2·等活性粒子,且产物的总生成量超过了根据法拉第定律计算的产量,每通过1 mol电子可生成12 mol·OH。·OH氧化能力非常强,可以无选择地降解各种有机物。文章探讨了电压、初始浓度、pH、催化剂Fe2+等因素对辉光放电降解直接黑EX效果的影响。用紫外可见吸收光谱检测了染料的降解过程。实验表明:利用该方法可以使水中染料大部分降解。直接黑EX优化降解条件为:工作电压610 V,pH 3.12,Fe2+催化作用下降解效率明显提高。%Glow discharge electrolysis (GDE) is a new kind of electrochemical technique for producing plasma. In the glow discharge electrolysis, inert electrolyte solution can produce a lot of active species, such as ·OH, ·H, e-aq, HO2·, and the total yield of product is more than the calculated yield according to Faraday law, for example, each 1 mol electrons can generate 12 mol ·OH. The oxidation ability of ·OH is very strong and it can degrade various organic matter without selection. This work discussed the effect of the voltage, initial concentration, pH and catalyst Fe2+on the degradation of Direct Black EX using glow discharge plasma. The degradation of Direct Black EX was monitored by UV-visible absorption spectra. Experiments showed that this method can degrade most dye in the water. The optimal degradation conditions were as follows:working voltage 610 V;pH 3.12;The catalyst Fe2+can promote the degradation of Direct Black EX.

  2. 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.

  3. 大气压氦气介质阻挡斑图放电与辉光放电的转换条件及其演化过程%Conversion and Evolution Process of Patterned Discharges to Glow Discharges in Atmospheric-pressure Helium Dielectric Barrier Discharge

    Institute of Scientific and Technical Information of China (English)

    郝艳摔; 郑彬; 刘耀阁

    2012-01-01

    为研究在大气压氦气中斑图放电与辉光放电的转换,利用高频高压电源进行了大气压氦气介质阻挡放电(DBD)试验。通过测量外加电压与回路电流随时间变化的波形,并利用增强型电荷耦合器件(intensifiedchargecoupleddevice,ICCD)相机同时拍摄电极侧面和底面的短时曝光放电图像,研究了斑图放电和辉光放电的放电模式以及2种放电模式的转换规律。研究结果显示:放电起始时放电空间出现斑图放电,每个斑图放电单元经历了由汤森放电向辉光放电的演化过程;放电起始后降低外加电压,可得到稳定的单脉冲辉光放电;升高外加电压,回路电流逐渐变成双脉冲,斑图放电单元面积变小,放电单元数增多,放电逐渐均匀;外加电压升高到回路电流变为3脉冲及以上时放电转化为多脉冲辉光放电。以上结果证明:单个回路电流波形不能用来判断放电的均匀性;随着外加电压的升高,斑图放电向辉光放电的转换过程实质上是局部辉光放电向整体辉光放电的演化过程。%In order to study the conversion of spational-temporal patterned discharges to glow discharges in atmospheric helium, dielectric barrier discharges {DBDs) were obtained using a high-frequency power supply in atmospheric helium. Waveform of the applied voltage and loop current were measured and short exposure time discharge photos were taken with an intensified charge-couple device {ICCD} to investigate the characteristics of spatio-temporal patterned discharges, especially their conversion to glow discharges. The characteristics of glow discharges were also discussed. The results showed that spatio-temporal patterned discharges occurred when the applied voltage was high enough. Each pattern shared similar characteristics with a glow discharge and its physical process started from a Townsend discharge to a glow one. After a patterned

  4. 辉光放电低温等离子体分解乙醇水溶液制氢%Hydrogen Production from the Decomposition of Ethanol Aqueous Solution Using Glow Discharge Plasma Electrolysis

    Institute of Scientific and Technical Information of China (English)

    陶晶亮; 熊源泉

    2013-01-01

      在辉光放电分解乙醇制氢过程中,高能电子在反应中起到了最为关键的作用,非法拉第效应使得电流效率获得大幅度提升,产物产量远远高于理论产量.本文研究了乙醇水溶液辉光放电等离子体电解制氢的过程.实验研究发现,辉光放电分解乙醇水溶液的产物主要以H2和CO为主,还有少量的C2H4、CH4、O2和C2H6. H2体积分数能达到59%以上, CO为20%左右.通过对影响辉光放电的因素进行实验后发现:乙醇体积分数的大小不会影响辉光放电的伏安特性参数;电导率的提高会使‘Kel ogg区’收窄,同时使放电尽快进入辉光放电.此外,乙醇体积分数越高H2体积分数越低,产气速率在乙醇体积分数为30%和80%附近时达到极大值;提高放电电压和电导率对辉光放电的影响规律是相类似的,其实质都是增大了辉光放电加载在等离子鞘层两端的电压, H2体积分数基本不随二者的变化而变化,但提高溶液的电导率更有利于减少辉光放电引起的焦耳热.%High-energy electrons play the most important role in the decomposition of ethanol aqueous solutions under glow discharge plasma electrolysis (GDE). The non-Faradaic currents greatly improve, resulting in the actual gas production yield exceeding the theoretical yield. In this paper, we investigated a novel process of hydrogen generation from ethanol decomposition by GDE. The main gaseous products were H2 and CO;in addition to smal amounts of C2H4, CH4, O2, and C2H6. The H2 volume fraction was above 59%and CO was 20%. We conclude that voltages of points C and D (VC and VD) do not change with the electrolyte concentration, but the 'Kel ogg area' becomes narrower with increasing electrolyte conductivity and the glow discharge is easier to attain. In addition, with increasing ethanol volume fraction, the H2 volume fraction decreases. The maximum gas production rate occurred for ethanol

  5. Modelling study of dielectric barrier glow discharge in Ar/NH3 mixture at atmospheric pressure%大气压Ar/NH3介质阻挡辉光放电的仿真研究

    Institute of Scientific and Technical Information of China (English)

    张增辉; 张冠军; 邵先军; 常正实; 彭兆裕; 许昊

    2012-01-01

    为了研究火气压下氩气(Ar)中掺杂氨气(NH3)的Ar/NH3介质阻挡辉光放电的放电机理,通过建立一‘个多粒子的自洽耦合流体模型,采用有限元方法进行数值计算,得到了气体间隙压降、介质表面电荷密度、放电电流密度随时间的周期变化波形,以及带电粒子、中性粒子与空间电场强度的时空分布.仿真计算结果表明:气体间隙的周期击穿过程主要由气隙电压控制,并受气隙两侧介质极板上积聚的表面电荷的影响.气隙间带电粒子密度和电场强度的时空分布表明本文的放电过程存在阴极位降区、负辉区、法拉第暗区、等离子体正柱区等辉光放电的典型区域,放电模式为大气压辉光放电.在Ar/NH3等离子体中,主要的正离子为NH+,其次为Ar2+,主要的负离子为NHi:NH3分解产生的主要的激发态分子为NH,NH2和N2H3,而最终的稳态产物主要是N2和H2.%In order to investigate the mechanism of dielectric barrier glow discharge in Ar/NH3 mixture at atmospheric pressure, a multiple particles self-consistent coupled fluid model is proposed. And the finite-element method is used in the numerical calculation model, so the periodically varying waveforms of gas voltage, dielectric surface charge density and discharge current density are investigated. The spatial and temporal distributions of charged and neutral particles density and space electrical field strength are also obtained. The simulation results show that the periodic breakdown process of the gas gap is controlled by the gas voltage, and affected by dielectric surface charges. The spatiotemporal distributions of charged particle density and electrical field strength show that the discharge under conditions considered in this model is a typical atmospheric pressure glow discharge, and that in the discharge process there exist an obvious cathode fall region, a negative glow region, a

  6. 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)

  7. Coupling of multi-walled carbon nanotubes/polydimethylsiloxane coated stir bar sorptive extraction with pulse glow discharge-ion mobility spectrometry for analysis of triazine herbicides in water and soil samples.

    Science.gov (United States)

    Zou, Nan; Yuan, Chunhao; Liu, Shaowen; Han, Yongtao; Li, Yanjie; Zhang, Jialei; Xu, Xiang; Li, Xuesheng; Pan, Canping

    2016-07-29

    An analytical method based on stir bar sorptive extraction (SBSE) coupled with pulse glow discharge-ion mobility spectrometry (PGD-IMS) was developed for analysis of three triazine pesticide residues in water and soil samples. An injection port with sealing device and stir bars hold device were designed and constructed to directly position the SBSE fiber including the extracted samples into the heating device, making desorption and detection of analytes proceeded simultaneously. The extraction conditions such as SBSE solid phase material, extraction time, extraction temperature, pH value and salt concentration were optimized. Mixture of MWCNTs-COOH and PDMS were shown to be effective in enriching the triazines. The LODs and LOQs of three triazines were found to be 0.006-0.015μgkg(-1) and 0.02-0.05μgkg(-1), and the linear range was 0.05-10μgL(-1) with determination coefficients from 0.9987 to 0.9993. The SBSE-PGD-IMS method was environmentally friendly without organic solvent consumption in the entire experimental procedures, and it was demonstrated to be a commendable rapid analysis technique for analysis of triazine pesticide residues in environmental samples on site. The proposed method was applied for the analysis of real ground water, surface water and soil samples.

  8. Attachment and growth of fibroblasts on poly(L-lactide/epsilon-caprolactone) scaffolds prepared in supercritical CO2 and modified by polyethylene imine grafting with ethylene diamine-plasma in a glow-discharge apparatus.

    Science.gov (United States)

    Aydin, H M; Türk, M; Calimli, A; Pişkin, E

    2006-09-01

    In this study, a copolymer of L-lactide and epsilon-caprolactone (Mn: 73,523, Mw: 127,990 and PI: 1.74) was synthesized by ring-opening polymerization by using stannous octoate as the catalyst. FTIR, 1H-NMR and DSC confirmed the copolymer formation. The copolymer films were prepared and a novel method was developed to produce highly porous sponges for potential use in tissue engineering. Films were subjected to supercritical CO2 at 3300 psi and 70 degrees C to create porous structures for production of possible tissue engineering scaffolds. The pore sizes were in the range of 40-80 microm. The copolymer films were pre-wetted with polyethylene imine (PEI) and then treated with ethylene diamine (EDA)-plasma in glow-discharge apparatus. Gas plasma surface modification of three-dimensional scaffolds fabricated by supercritical carbon dioxide technique was demonstrated to enhance cell adhesion, proliferation, and differentiation over 6 days in culture using L929 fibroblast cell line. Alkaline phosphatase (ALP) activity and glucose uptake in cell culture medium were followed in the cell culture experiments. Fibroblastic cell attachment and growth on the EDA-plasma treated scaffolds were rather low. However, both cell attachment and growth were significantly increased by PEI pre-treatment before EDA-plasma. The changes in ALP activity and glucose uptake also supported the cell growth behavior on these PEI and EDA-plasma treated scaffolds.

  9. 接触辉光放电等离子体降解苯酚过程中的毒性变化%Degradation and toxicity change of phenol in contact glow discharge electrolysis

    Institute of Scientific and Technical Information of China (English)

    赵晓青; 金星龙; 汪志荣

    2012-01-01

    Due to its highly toxicity and refractory degradation in industrial wastewater treatment, it is important to study the toxicity changes of phenol in the degradation process. This paper investigated the toxicity change during phenol degradation by contact glow discharge plasma (CGDE) with chlorella vulgaris as testing organism. The degradation rate of 1.0 g/L phenol after 90 min CGDE treatment is 16.0% , and EC50 reduced from 179.5 to 128.9 and then gradually increase to 413. 3 mg/L, showed that the toxicity first slightly increases and then gradually reduce. With 30.0 mg/L Fe2+ in presence of solution, phenol degradation rate increased to 32.7% and EC50 rose from 179.5 to 260.9 and then down to 234. 3 mg/L, the toxicity reduced and then slightly increases. The results indicated that Fe2+ was of great benefit to the rapid degradation of the phenol, but 90 min CGDE treatment still could not effectively reduce the toxicity of phenol solution.%苯酚是工业废水中一种常见的高毒性难降解有机污染物,研究其降解过程中的毒性变化对废水处理和生态环境保护具有重要意义.本文以小球藻为受试生物,测定了接触辉光放电等离子体(CGDE)降解苯酚过程中的毒性变化.CGDE降解1.0 g/L苯酚90 min,降解率为16.0%,降解过程中EC50从179.5降低至128.9而后逐渐升高到413.3 mg/L,表明毒性先小幅增大后逐渐降低.加入30.0 mg/L Fe2+后,苯酚降解率增加了32.7%,降解过程中EC50从179.5升至260.9后降低至234.3 mg/L,毒性先降低后略有增大.结果表明:Fe2+有利于苯酚的快速降解,但90 min内不能有效降低CGDE降解苯酚过程中的毒性.

  10. 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

  11. Effect of double glow plasma surface chromizing on high-temperature oxidation resistance of TC4 titanium alloy%TC4合金双辉等离子渗Cr高温氧化行为

    Institute of Scientific and Technical Information of China (English)

    魏东博; 张平则; 姚正军; 梁文萍; 缪强; 徐重

    2011-01-01

    Isothermal oxidation behavior of TC4 titanium alloy,which was chromized by the double glow plasma surface alloying technology(DGP),were investigated at 650 ℃,750 ℃ and 850 ℃.The results show that the chromizing layer consists of surface loose layer,compact deposited layer and Ti-Cr mutual diffusion layer.The diffusion layer has better oxidation resistance compared with NiCrAlY thermal barrier coating.The ratio of Cr to Ti content in the diffusion layer exhibits gradient distribution by Cr,Cr1.97Ti1.07 and CrTi4.Under oxidation circumstance,Cr,Ti and Al diffuse outward to form multilayer oxide films,which prevent inward diffusion of oxygen.At 650 ℃,the oxidation films consist of two layers: the external Cr2O3 layer and the internal TiO2 layer.At 750 ℃,a mixed oxide layer containing Cr2O3 and TiO2 is formed beneath the Cr2O3 layer and TiO2 layer,whereby Ti(Cr,Al)2 Laves phase is observed in the Ti-depleted layer.At 850 ℃,a mixed oxide layer containing TiO2,Ti2O3 and Ti3O5 is formed beneath the Cr2O3 layer and Al2O3 layer,whereby Ti(Cr,Al)2 Laves phase and Kirkendall voids are formed in the depletion layer.%研究了双层辉光等离子渗Cr对TC4合金650、750、850℃恒温氧化性能的影响。结果表明:渗Cr后,表面梯度合金层显著提高了TC4合金的高温氧化性能,Ti-Cr互扩散层可有效阻止氧向基体扩散。氧化过程中,Ti、Cr向外扩散形成TiO2/Cr2O3氧化膜,其形态与氧化温度有关。850℃氧化100 h后,渗Cr试样表面形成致密Cr2O3膜,恒温氧化性能优于NiCrAlY热障涂层。

  12. Peakfitter — an integrated Excel-based Visual Basic program for processing multiple skewed and shifting Gaussian-like spectral peaks simultaneously: application to radio frequency glow discharge ion trap mass spectrometry

    Science.gov (United States)

    Eanes, Ritchie C.; Marcus, R. Kenneth

    2000-04-01

    This article is an electronic publication in Spectrochimica Acta Electronica (SAE), a section of Spectrochimica Acta Part B (SAB). The hardcopy text is accompanied by an electronic archive, stored on the SAE homepage at (http://www.elsevier.nl/locate/sabe). The archive contains program and data files. The main article discusses the scientific spectroscopic and instrumental aspects of the subject and explains the purpose of the program and data files. The work deals with a Microsoft Excel Visual Basic program, Peakfitter, which can process multiple Gaussian-shaped spectral peaks quickly and easily. The program employs Microsoft Excel Solver to process any Gaussian-like spectra that can be opened in Microsoft Excel 97. Up to three peaks in one to 225 spectra, each containing up to 2000 data points can be processed per data file to give background corrected peak areas for both raw data and its associated fit data as calculated by the trapezoidal method or by simple successive addition of channel intensities across each peak. Concurrently output also includes fit peak heights for Gaussian-shaped spectral peaks. Use of other statistical distributions such as the Lorentzian model requires only slight modification to a template file. Hence, Peakfitter was actually written as two application programs, 'Gaussfitter' and 'Lorenfitter' to accommodate spectra of Gaussian or Lorentzian character, respectively. Written initially to process data from a radio frequency glow discharge ion trap mass spectrometer (rf-GD/ITMS), the program is useful for processing sequentially acquired spectra, which have a limited number of data points across each peak. The user may examine and manipulate program variables in cases where the raw data is skewed with respect to the fit data. An assessment of Peakfitter is given using rf-GD/ITMS elemental analysis and ion-molecule reaction data. Peakfitter's (i.e. 'Gaussfitter's) utility in processing rf-GD/ITMS spectra is characterized by a slight

  13. Synthesis of composite superabsorbent resin by using glow-discharge electrolysis plasma%辉光放电电解等离子体引发合成复合高吸水性树脂

    Institute of Scientific and Technical Information of China (English)

    任杰; 陶丽红; 高锦章; 李亚萍; 刘宏伟

    2012-01-01

    以丙烯酸、丙烯酰胺和腐植酸钠为原料,N,N’-亚甲基双丙烯酰胺为交联剂,在水溶液中利用辉光放电电解等离子体引发制备了聚(丙烯酸-丙烯酰胺)/腐植酸钠(P(AA-AM)/SH)复合高吸水性树脂.考查了放电电压、放电时间、交联剂含量、腐植酸钠(SH)含量、丙烯酸(AA)与丙烯酰胺(AM)摩尔比和丙烯酸中和度等因素对树脂吸水量的影响.用红外光谱(FT-IR)和热重分析(TGA)分别对产品的结构和稳定性进行了表征,并探讨了pH及NaCl溶液对树脂溶胀行为的影响以及反复溶胀能力和保水率.结果表明,在最佳合成条件下,所得复合树脂具有较高的吸水性和耐盐性,对蒸馏水的吸收量为1 198 g·g-1,对0.9%NaCl溶液的吸收量为124 g·g-1.%Poly(acrylic acid-acrylamide)/sodium humate (P (AA-AM)/SH) composite superabsorbent resin is prepared in aqueous solution by using glow-discharge electrolysis plasma. Acrylic acid, acrylamide and sodium humate are used as raw material and N, N'-methylenebisacrylamide as a crosslinking agent. The synthesis conditions, such as the discharge voltage, discharge time, crosslinking agent, amounts of sodium humate. Molar ratio of A A/AM and neutralization degree of acrylic acid, are examined in detail. The structure and thermal stability of the resulting products are characterized by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis(TGA). In addition, the influence of pH and NaCl solution on the swelling behavior, reswelling property and water retention are also investigated. The results show that at the optimal synthesis conditions, the superabsorbent resin has higher water absorbency and salt tolerance, I. E. , 1 198 g·g-1 for distilled water and 124 g·g-1 for 0.9% sodium chloride solution.

  14. Acting green elicits a literal warm glow

    NARCIS (Netherlands)

    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(1,2). We argue that people might also be motivated by intrinsic rewards: doing the right thing (such as acting environmentally friendly) elicit

  15. A glowing tribute to CERN craftsmanship

    CERN Multimedia

    2001-01-01

    Didier Lombard, metalworker in EST Division, has been crowned 'France's Top Craftsman'. It's the second time this prestigious title has been bestowed upon a CERN staff member. The reputation of CERN's craftsmanship outside the Laboratory just keeps on growing! For the second time in a row, a member of EST Division's Manufacturing Facilities Group has been named France's Top Craftsman. After Michel Caccioppoli in 1997, Didier Lombard has now taken his place on the roll of honour. This triennial competition seeks to honour workers and skilled craftspeople in two hundred different trades, from pastry-makers and painters to lacemakers and goldsmiths. To win the medal, competitors must produce an object on the basis of a compulsory specification. 3412 competitors entered this 21st edition of the contest, which covered the period 1997 to 2000. Only 846 of the original entrants eventually presented their work and in the end only 321 were honoured - just two in Didier Lombard's category, metalworking. To be fair, the...

  16. Three spacecraft observe Jupiter's glowing polar regions

    Science.gov (United States)

    1996-09-01

    The aurorae on Jupiter are like the Aurorae Borealis and Australis on the Earth, although visible only by ultraviolet light. They flicker in a similar way in response to variations in the solar wind of charged particles blowing from the Sun. While Galileo monitored the changing environment of particles and magnetism in Jupiter's vicinity, IUE recorded surprisingly large and rapid variations in the overall strength of the auroral activity. IUE's main 45-centimetre telescope did not supply images,but broke up the ultraviolet rays into spectra, like invisible rainbows, from which astrophysicists could deduce chemical compositions, motions and temperatures in the cosmic objects under examination. In the case of Jupiter's aurorae, the strongest emission came from activated hydrogen atoms at a wavelength of 1216 angstroms. The Hubble Space Telescope's contributions to the International Jupiter Watch included images showing variations in the form of the aurorae, and "close-up" spectra of parts of the auroral ovals. Astronomers will compare the flickering aurorae on Jupiter with concurrent monitoring of the Sun and the solar wind by the ESA-NASA SOHO spacecraft and several satellites of the Interagency Solar-Terrestrial Programme. It is notable that changes in auroral intensity by a factor of two or three occurred during the 1996 observational period, even though the Sun was in an exceptionally quiet phase, with very few sunspots. In principle, a watch on Jupiter's aurorae could become a valuable means of checking the long-range effects of solar activity, which also has important consequences for the Earth. The situation at Jupiter is quite different from the Earth's, with the moons strongly influencing the planet's space environment. But with Hubble busy with other work, any such Jupiter-monitoring programme will have to await a new ultraviolet space observatory. IUE observed Jupiter intensively in 1979-80 in conjunction with the visits of NASA's Voyager spacecraft, and again in 1994, when the fragments of Comet Shoemaker-Levy 9 hit Jupiter in a spectacular series of events. The explosive impacts appeared to repress the auroral activity at the time, suggesting a remarkable effect of comet dust on the charged particles creating the aurorae in Jupiter's atmosphere. The new results on variability due to other causes will help astronomers to assess that effect more confidently. They will also compare the 1994 and 1996 IUE data to see how the atmosphere of Jupiter has recovered from the impacts. In Jupiter's vicinity IUE registered ultraviolet emissions from oxygen and sulphur atoms littering the orbit of Io, and probably released by volcanic emissions from that peculiar moon. This Io Torus is highly variable too. The record of its ultraviolet emissions, both within the 1996 campaign and in comparison with earlier observations, will help the astronomers to understand the reasons for the variations. A remarkable history The close scrutiny of Jupiter and its moons was the final astronomical task of IUE, before the termination of space operations on 30 September 1996. Over the past few months the IUE science team and collaborating astronomers in Europe have fulfilled a wish-list of important observations precluded by the intense demands on their ultraviolet space observatory throughout its life of nearly nineteen years. The observations in the final science programme confirmed and extended IUE's record, as the most reliable and productive astronomical satellite that ever flew. In March of this year the spacecraft was ailing, with only one of its six gyros still functioning, which severely limited the scope of its original mission. By skillful control and spacecraft engineering it went on harvesting new data, including prolonged observations of Comet Hyakutake. The concluding campaigns that began in April targeted the gamma-ray emitting "blazar" Markarian 421, various other active galaxies, and stellar winds, as well as Jupiter. "I am sad but also privileged to be the last observer with IUE" says Rene Prang of Orsay, France, who was in charge of the Jupiter programme. "At the end it provided us wit 800 observations of Jupiter, so it was still doing important work at the leading edge of planetary astronomy and space research". Created jointly by NASA, the UK government and ESA, IUE was supposed to last for three years, when it was launched on 26 January 1978. Instead, the 700-kilogram spacecraft went on supplying astronomers with ultraviolet spectroscopic information available from no other spacecraft until the launch of the Hubble Space Telescope in 1990. As the only space observatory offering them a hands-on mode of operation, at ESA's ground station at Villafranca near Madrid, IUE was a favourite with astronomers. An astounding total of 114,000 individual observations of planets, stars, galaxies and quasars assures the spacecraft a cherished place in the history of astronomy. IUE supplied the bedrock ultraviolet data on top events during its lifetime. These included the apparition of Halley's Comet in 1986. At the comet's approach in September 1985, IUE detected the ultraviolet signature of water molecules, and regular observations thereafter showed that the comet shed 300 million tonnes of water during its visit to the Sun's vicinity. With the explosion of a star in the Large Magellan Cloud, as Supernova 1987A, IUE was trained instantly on the scene. Comparisons with previous IUE observations of the same region revealed exactly which star had blown up. The characteristic emissions of chemical elements flung into space by the explosion were also identified, IUE's detection of a delayed light echo, from a ring of dust surrounding the defunct star, later enabled the Hubble Space Telescope to measure the distance to Supernova 1987A precisely. Eruptions in the nuclei of active galaxies were a prominent theme in IUE's work throughout its lifetime. Intensive studies of selected galaxies, sometimes in concert with X ray observations by other spacecraft, have built up unprecedented albums of data from which astronomers can puzzle out the behaviour of these violent objects. After the termination of space operations, the IUE mission continues on the ground with the task of reprocessing all the raw data ever transmitted from the spacecraft, using the latest computational techniques. This will create the IUE archive of ultraviolet spectra, from which future generations of astronomers will continue to cull unique information on nearly 10,000 objects in the sky. Over the years, frequent international symposia have digested the results from IUE. At a special meeting of the European Astronomical Society next year November in Sevilla (Spain), astronomers will have the opportunity to put the latest findings in perspective, in relation to all the other observations since 1978. "When NASA decided last year to terminate its operations as the leading partner in IUE, we expanded our European operations at Villafranca" comments Roger Bonnet, ESA's Science Director. "Although we were unable to prolong the life of the spacecraft indefinitely, it is gratifying to see what excellent use the astronomers have made of this final phase of IUE's long career". An image illustrating IUE's last observations of the Jupiter Polar regions is available on request from ESA Public Relations, Paris (Tel : +33.1-53.69.7155 Fax : +33.1-53.69.76.90)

  17. 大气压氩气射流等离子体的光谱特性研究%Investigation on the Spectral Characteristics of a Plasma Jet in Atmospheric Argon Glow Discharge

    Institute of Scientific and Technical Information of China (English)

    李雪辰; 张春艳; 李霁媛; 鲍文婷

    2015-01-01

    voltage (U= 13.5 kV) ,the length of the plasma plume increases with the gas flow rate .For a constant value of the gas flow rate(10 L・min-1 ) , the length of the plasma plume increases with the voltage .The voltage is inversely proportional to the current under the constant gas flow rate .In other words ,the voltage decreases with the discharge current ,which indicates that a glow discharge is formed in the plasma jet .Optical emission spectrum in 300 to 800 nm is collected from the direct-current excited plasma jet .By Boltz-mann plot method ,the excited electron temperature of the plasma plume is investigated as a function of the applied voltage or the gas flow rate .Results show that the excited electron temperature increases with decreasing applied voltage under the constant gas flow .Moreover ,it increases with decreasing the gas flow under the constant voltage .Based on the discharge theory ,these experimental phenomena are explained qualitatively .These results are of great importance to the development of atmospheric pressure uniform discharge plasma source and its application in industrial field .

  18. 射频功率对辉光放电H2/C4H8等离子状态的影响%Influence of radio-frequency power on the state of H2/C4H8 glowing discharge plasma

    Institute of Scientific and Technical Information of China (English)

    李蕊; 何智兵; 何小珊; 牛忠彩; 杨向东

    2012-01-01

    采用辉光放电技术和等离子体质谱诊断技术, 研究了H2/C4H8混合气体等离子体中正离子成分及主要正离子能量随射频功率的变化规律, 并分析了H2/C4H8混合气体主要的离解机理和形成过程. 研究表明: 随着射频功率的增加, 碳氢碎片离子的浓度增加, 在20 W时达到最大值, 25 W后有所减小. 当射频功率小于10 W时, H2/C4H8混合气体等离子体中C4H9+相对浓度最大, 当功率大于或等于10 W时, C3H3+相对浓度最大. 随着射频功率的增大, 碳氢碎片离子的能量逐渐增加. 对H2/C4H8混合气体等离子体的组成与能量进行的定性分析, 将为H2/C4H8混合气体辉光放电聚合物涂层工艺参数优化提供参考.%Taking advantage of the glowing discharge technology and plasma mass spectrometry diagnosis technology, the variation rules of positive ion species and energy with power in H2/C4H8 mixture gas are investigated. The characteristic ions are measured and their forming process is discussed. The results show that the intensity of the C-H segment ions in the H2/C4H8 plasma increases with radio-frequency (RF) power increasing, the intensity reaches a maximum at an RF power of 20 W, and then reduces after the RF power has reached 25 W. The relative concentration of m/e 57 (C4H9+) is highest when the power is less than 10 W, and when the power is more than 10 W, the relative concentration of m/e 39 (C3H3+) reaches a maximum. The energy of the C-H segment ions increases gradually with the increase of RF power. The qualitative analyses of H2/C4H8 plasma composition and energy will be beneficial to improving the fabrication technology of glowing discharge polymer coating.

  19. 口腔用近β钛合金双层辉光离子渗氮改性后腐蚀性能的实验研究%Experimental study on the corrosion behavior of a type of oral near β-type titanium alloys modified with double glow plasma nitriding

    Institute of Scientific and Technical Information of China (English)

    温科; 李风兰

    2015-01-01

    Objective To study the electrochemical corrosion performance of a type of biomedical materials near beta titanium alloy(Ti-3Zr-2Sn-3Mo-25Nb, TLM) in artificial saliva before and after nitride changing, and to provide clinical basis for clinical application of titanium alloy TLM.Methods The double glow plasma alloying technology was used to nitride the surface of titanium alloy TLM.The surface properties of the modified layer were observed and tested by optical microscope, scanning electron microscope, glow discharge spectrum analyzer, X-ray diffraction and micro hardness tester.Then, electrochemical measurement system was used to test and compare titanium alloy TLM's electrochemical corrosion in artificial saliva before and after its surface change.Finally, the surface morphology of the original titanium alloy and the modified layer was compared by scanning electron microscope.Results By the technology of double glow plasma nitriding, the surface of the titanium alloy TLM had been successfully nitrided with a modified layer of 4-5 βm in thickness, uniform and compact.Its main compositions were Ti and Ti2N.The Microhardness of modified layer also had been improved from (236.8±5.4) to (871.8±5.2) HV.The self-corrosion potential in electrochemical corrosion tests had been increased from-0.559 V to-0.540 V,while the self-corrosion current density had been reduced from 2.091 × 10-7 A/cm2 to 7.188× 10-8 A/cm2.Besides, alternating-current impedance(AC Impedance) had also been increased.With the scanning electron microscope, it's obvious that the diameter of corrosion holes on modified layer were approximately 10 βm.As to the diameter and number of corrosion holes on modified layer, they had been decreased comparing with the original titanium alloy.Conclusions The type of near beta titanium alloy TLM can construct a nitriding modified layer on its surface.Meanwhile, the performance of its anti-corrosion in artificial saliva has been improved, comparing to the

  20. Friction and wear properties of double glow plasma carburized layer of Ti2AlNb base O phase alloy%Ti2AlNb基O相合金双辉等离子渗碳层摩擦磨损性能

    Institute of Scientific and Technical Information of China (English)

    杨晶晶; 缪强; 梁文萍; 李龙; 任蓓蕾; 朱丹阳

    2013-01-01

    Double glow plasma carburized layer was carried out on the surface of Ti2AlNb base O phase alloy to improve its wear-resistance.The microstructure,element distribution,phases,hardness and wear resistance of the carburized layer were analyzed by SEM,EDS,XRD,hardness tester and friction wear testing machine.The results show that a carburized layer is formed about 30 μn,and surface hardness of the carburized layer is 1053-V0.1 and it gradually decreases along the depth.The general friction coefficient of the carhnrized layer and matrix is 0.4 and 0.75,respectively.The specific wear rate of carburized layer is 1/17 of the matrix.The wear resistance of Ti2AlNb base O phase alloy is improved significantly by plasma carburizing.%利用双层辉光等离子表面合金化技术在Ti2AlNb基O相合金表面进行渗碳处理,采用SEM、EDS、XRD、硬度仪及摩擦磨损试验机对其组织成分、元素分布、相组成、硬度及耐磨性能进行研究.结果表明,在Ti2AlNb基O相合金表面形成了约30μm的渗碳层,渗碳层表面硬度为1053 HV0.1,且硬度随渗层厚度梯度递减.渗碳层和基体平均摩擦因数分别为0.4和0.75,渗碳层比磨损率为基体比磨损率的1/17.双层辉光等离子渗碳技术明显提高了Ti2A1Nb基O相合金的耐磨性.

  1. OOPIC Simulation of a Cylindrical Magnetron Glow Discharge

    Science.gov (United States)

    2008-03-01

    5] Arfken , G. 1985. Mathematical Methods for Physicists, 3rd ed. Orlando, FL: Academic Press, 502-504. [6] Morse, P. and Feshbach, H. 1953...endorsement by or approval of the U.S. Government. Destroy this report when no longer needed by any method that will prevent disclosure of its... methods for the charged-particle, neutral collisions with energy dependent cross sections. The partial differential equations in OOPIC are

  2. SWIR Hemispherical Air-Glow Plotting System SHAPS: Postprint

    Science.gov (United States)

    2010-06-01

    atmosphere, as modeled using the van Rhijn method (4). 60.-~-----~--~- -- 200 10 °07--0~5~~--~15~~-725~ .-3 15 4.5 T.mo (hour!.) Ttm ~ (hou’!!.) a...temporal variations in the irradiance, both short and long term, can be used to validate and calibrate physical models of atmospheric chemistry and...spatio- temporal variations in the irradiance. both short and long term. can be used to validate and calibrate physical models of atmospheric

  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. Uranium Glass: A Glowing Alternative to Conventional Sources of Radioactivity

    Science.gov (United States)

    Boot, Roeland

    2017-02-01

    There is a relatively simple way of using radioactive material in classroom experiments: uranium glass, which provides teachers with a suitable substance. By using the right computer software and a radiation sensor, it can be demonstrated that uranium glass emits radiation at a greater rate than the background radiation and with the aid of UV light a bright green luster appears. Therefore, with two pieces of uranium glass, students can learn about two different physical phenomena: fluorescence and radioactivity.

  5. Methane Conversion to C2 Hydrocarbons Using Glow Discharge Plasma

    Institute of Scientific and Technical Information of China (English)

    HU Miao; CHEN Jierong

    2007-01-01

    The infrared emission spectra of methane, H', CH and C2 hydrocarbons in natural gas were measured. The process of methane decomposition and C2 hydrocarbons formation was investigated. The experiment showed that the time and conditions of methane decomposition and C2 hydrocarbons formation were different. Methane conversion rate increased with the increase in the current and decrease in the amount of methane. Furthermore, an examination of the reaction mechanisms revealed that free radicals played an important role in the chain reaction.

  6. Glow Discharge Optical Spectroscopy of Ion Implanted Gallium Arsenide.

    Science.gov (United States)

    1979-12-01

    PECVD processes are silane (SiH4 ) plus either 47 t - Im ammonia (NH 3 ) or nitrogen (N2 ) or both. The chemical reactions are, 3SiH4+2N 2-Si3N 4+6H 2...Physics, 44:5183-5184 (Nov 1973). 68 I i . 13. Sawyer, R., Experimental Spectroscopy, New York: Dover Publication, Inc. (1963) 14. Kerm , W., R. Rosler...composition as functions of the follow- ing parameters: flow, pressure, substrate temperature, and RF power. Kerm , et al., (Ref 14) studied films grown

  7. Sky Glow from Cities: The Army Illumination Model v2

    Science.gov (United States)

    2011-09-01

    corresponding to one 10th magnitude star per square degree and will not be pursued further here). Benn and Ellison find that the sky brightness at La Palma ...not have electricity, liquid and pressurized lamps are 23 included. For these latter two, liquid Citronella, lamp oil , liquid paraffin and...Properties; AFGL-TR-79-0214; Air Force Geophysics Laboratory: Hanscom Air Force Base, MA, 1979. 19. Benn, C. R. and Ellison, S. L. La Palma Night-Sky

  8. Social Entrepreneurship in the Modern Economy: Warm Glow, Cold Feet

    NARCIS (Netherlands)

    B. Hoogendoorn (Brigitte)

    2011-01-01

    textabstractThis study tests and extends current knowledge on the causes of social entrepreneurship: a type of entrepreneurship that concerns the process of discovering, evaluating, and pursuing opportunities aimed at the creation of social value. In contrast to what is common in this research domai

  9. Investigation of Sheath Phenomena in Electronegative Glow Discharges.

    Science.gov (United States)

    1987-04-01

    al. 7 and Segur 3 similarly assumed a linearly decreasing electric field, but used the Monte Carlo model. These calculations are not considered self...fall region, was not examined. Since then Segur et al. 6 have coupled a Boltzmann solution for electrons with an analytical approximation to the...electrode distance (D) wee limited by the memory storage capability of a Cyber 74 computer. For 100% He, D was 2.2 cm and for the remaining He/HCI

  10. 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.

  11. Thermoluminescence glow curve of {gamma}-irradiated calcite

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S.D.; Ingotombi, S. [Manipur Univ. (India). Dept. of Physics

    1995-07-14

    The trapping parameters, namely the activation energy E, frequency factor s and b order of kinetics of the thermoluminescence (TL) peaks of calcites (brown and colourless varieties) irradiated with 4.08 kGy of {gamma}-rays, are determined using the least-squares curve-fitting technique. The electron lifetime {tau} of the peaks of calcite are calculated in order to estimate the upper limit of their utility in TL dating. (author).

  12. Inception of Snapover and Gas Induced Glow Discharges

    OpenAIRE

    2000-01-01

    Ground based experiments of the snapover phenomenon were conducted in the large vertical simulation chamber at the Glenn Research Center (GRC) Plasma Interaction Facility (PIF). Two Penning sources provided both argon and xenon plasmas for the experiments. The sources were used to simulate a variety of ionospheric densities pertaining to a spacecraft in a Low Earth Orbital (LEO) environment. Secondary electron emission is believed responsible for dielectric surface charging, and all subsequen...

  13. Restraint Effect of Filaments on Applied Voltage in Atmospheric Pressure Glow Discharge%Restraint Effect of Filaments on Applied Voltage in Atmospheric Pressure Glow Discharge

    Institute of Scientific and Technical Information of China (English)

    李森; 陈强; 刘忠伟

    2012-01-01

    In this study, argon and nitrogen were used as the discharge gases in radio-frequency (RF: 13.56 MHz) powered dielectric barrier atmospheric plasma. It was noticed that in single dielectric barrier discharge (DBD) with nitrogen as the discharge gas, or in argon plasma with a high applied power, micro-filament channels were easily formed. The channels in these two kinds of discharge were both constrictive on the bare metallic electrode and expansive on the opposite electrode covered with a quartz layer. The number of micro-channels was increased along with the input power, which caused the change in the I-V curve shape, i.e., the current kept increasing and the voltage fluctuated within a confined range. With double dielectric layers, however, no micro-channels appeared in the ICCD images, and the I-V curve demonstrated a totally different shape. It was assumed that micro-filaments exhibited a restraining effect on the discharge voltage. The mechanism of this restraining effect was explored in this work.

  14. Glow in the Dark: Fluorescent Proteins as Cell and Tissue-Specific Markers in Plants

    Institute of Scientific and Technical Information of China (English)

    Wenzislava Ckurshumova; Adriana E. Caragea; Rochelle S. Goldstein; Thomas Berleth

    2011-01-01

    Since the hallmark discovery of Aequorea victoria's Green Fluorescent Protein (GFP) and its adaptation for efficient use in plants,fluorescent protein tags marking expression profiles or genuine proteins of interest have been used to recognize plant tissues and cell types,to monitor dynamic cell fate selection processes,and to obtain cell type-specific transcriptomes.Fluorescent tagging enabled visualization in living tissues and the precise recordings of dynamic expression pattern changes.The resulting accurate recording of cell fate acquisition kinetics in space and time has strongly stimulated mathematical modeling of self-organizing feedback mechanisms.In developmental studies,the use of fluorescent proteins has become critical,where morphological markers of tissues,cell types,or differentiation stages are either not known or not easily recognizable.In this review,we focus on the use of fluorescent markers to identify and illuminate otherwise invisible cell states in plant development.

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

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaev, A. G.; Vizir, A. V.; Yushkov, G. Yu., E-mail: gyushkov@mail.ru; Frolova, V. P. [High Current Electronics Institute, Siberian Branch of the Russian Academy of Science, Tomsk 634055 (Russian Federation); Oks, E. M. [High Current Electronics Institute, Siberian Branch of the Russian Academy of Science, Tomsk 634055 (Russian Federation); Tomsk State University of Control Systems and Radioelectronics, Tomsk 634050 (Russian Federation)

    2016-02-15

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

  16. Glow-in-the-dark globular clusters: modelling their multiwavelength lanterns

    CERN Document Server

    Venter, C; Kopp, A; Clapson, A -C; de Jager, O C

    2014-01-01

    Globular clusters (GCs) are astronomical tapestries embroidered with an abundance of exotic stellar-type objects. Their high age promises a rich harvest of evolved stellar products, while the deep potential wells and high mass densities at their centres probably facilitate the formation of multiple-member stellar systems via increased stellar encounter rates. The ubiquity of low-mass X-ray binaries, thought to be the progenitors of millisecond pulsars (MSPs), explain the large number of observed GC radio pulsars and X-ray counterparts. The Fermi Large Area Telescope (LAT) recently unveiled the first gamma-ray GC pulsar (PSR J1823-3021A). The first observations of GCs in the GeV and TeV bands furthermore created much excitement, and in view of the above, it seems natural to explain these high-energy lanterns by investigating an MSP origin. An MSP population is expected to radiate several pulsed spectral components in the radio through gamma-ray wavebands, in addition to being sources of relativistic particles....

  17. Light pollution: Assessment of sky glow on two dark sky regions of Portugal.

    Science.gov (United States)

    Lima, Raul Cerveira; Pinto da Cunha, José; Peixinho, Nuno

    2016-01-01

    Artificial light at night (ALAN), producing light pollution (LP), is not a matter restricted to astronomy anymore. Light is part of modern societies and, as a consequence, the natural cycle day-night (bright-dark) has been interrupted in a large segment of the global population. There is increasing evidence that exposure to certain types of light at night and beyond threshold levels may produce hazardous effects to humans and the environment. The concept of "dark skies reserves" is a step forward in order to preserve the night sky and a means of enhancing public awareness of the problem of spread of light pollution worldwide. The aim of this study was to assess the skyglow at two sites in Portugal, the Peneda-Gerês National Park (PNPG) and the region now known as Dark Sky Alqueva Reserve. The latter site was classified as a "Starlight Tourism Destination" by the Starlight Foundation (the first in the world to achieve this classification) following a series of night sky measurements in situ described herein. The measurements at PNPG also contributed to the new set of regulations concerning light pollution at this national park. This study presents the first in situ systematic measurements of night sky brightness, showing that at the two sites the skies are mostly in levels 3 to 4 of the Bortle 9-level scale (with level 1 being the best achievable). The results indicate that the sources of light pollution and skyglow can be attributed predominantly to contamination from nearby urban regions.

  18. A New Glow on the Chromatography of M&M Candies

    Science.gov (United States)

    Birdwhistell, Kurt R.; Spence, Thomas G.

    2002-07-01

    This lab experiment for undergraduate or high school students presents the separation and analysis of dyes in the candy shell of M&M chocolate candies. The dyes in the shells of M&Ms are separated using paper chromatography and are identified by comparison of the Rf values, color, and fluorescence properties with those of standard FD&C ([U.S. Federal] Food, Drug, and Cosmetic Act) dyes. The experiment introduces students to chromatography of mixtures, compound identification by using Rf values, and fluorescence. They learn about fluorescence and how it appears in everyday substances and can be used to help identify compounds.

  19. Ghostly Glow Reveals a Hidden Class of Long-Wavelength Radio Emitters

    Science.gov (United States)

    2008-10-01

    (Washington, DC. 08)- A team of scientists, including astronomers from the Naval Research Laboratory (NRL), have detected long wavelength radio emission from a colliding, massive galaxy cluster which, surprisingly, is not detected at the shorter wavelengths typically seen in these objects. The discovery implies that existing radio telescopes have missed a large population of these colliding objects. It also provides an important confirmation of the theoretical prediction that colliding galaxy clusters accelerate electrons and other particles to very high energies through the process of turbulent waves. The team revealed their findings in the October 16, 2008 edition of Nature. This new population of objects is most easily detected at long wavelengths. Professor Greg Taylor of the University of New Mexico and scientific director of the Long Wavelength Array (LWA) points out, "This result is just the tip of the iceberg. When an emerging suite of much more powerful low frequency telescopes, including the LWA in New Mexico, turn their views to the cosmos, the sky will 'light up' with hundreds or even thousands of colliding galaxy clusters." NRL has played a key role in promoting the development of this generation of new instruments and is currently involved with the development of the LWA. NRL radio astronomer and LWA Project Scientist Namir Kassim says "Our discovery of a previously hidden class of low frequency cluster-radio sources is particularly important since the study of galaxy clusters was a primary motivation for development of the LWA." The discovery of the emission in the galaxy cluster Abell 521 (or A521 for short) was made using the Giant Metrewave Radiotelescope (GMRT) in India, and its long wavelength nature was confirmed by the National Science Foundation's (NRAO) Very Large Array (VLA) radio telescope in New Mexico. The attached image shows the radio emission at a wavelength of 125cm in red superimposed on a blue image made from data taken by the Chandra X-ray Observatory. X-ray Chandra X-ray Image The X-ray emission comes from hot thermal gas, a well-known sign-post of massive galaxy clusters. Furthermore, its elongated shape indicates that the cluster has undergone a recent violent collision or "merger event" in which another group or cluster of galaxies was swallowed up by the gravitational potential of the main cluster. Interferometrics Inc. and NRL scientist Tracy Clarke, who is also the LWA System Scientist, notes "In addition to teaching us about the nature of Dark Matter, merging clusters are also important in studies of the mysterious nature of Dark Energy. Understanding these two strange components of the Universe will help us understand its ultimate destiny." In the radio image there is a strong, oblong source of emission located on the lower left periphery of the X-ray gas detected by Chandra; this is a separate source. In the center of the cluster, within the region indicated by a dashed circle, there is radio emission which changes significantly with wavelength. At the longest wavelength (125 cm, shown) it is clearly detected, but at a wavelength of 49 cm it is much fainter, and it is almost entirely gone at 21 cm wavelength. This multi-wavelength picture of the diffuse emission is in good agreement with theoretical predictions for particle acceleration by turbulent waves generated by a violent collision. People Who Read This Also Read... Black Holes Have Simple Feeding Habits NASA’s Swift Satellite Catches First Supernova in The Act of Exploding Oldest Known Objects Are Surprisingly Immature Chandra Data Reveal Rapidly Whirling Black Holes In a broader astrophysical context, galaxy clusters are the largest gravitationally bound systems in the Universe and their collisions are the most energetic events since the Big Bang. Says team leader Gianfranco Brunetti (Instituto di Radioastronomia, Bologna, Italy), "The A521 system provides evidence that turbulence acts as a source of particle acceleration in an environment that is unique in the Universe due to its large spatial and temporal scales, a

  20. Jupiter's Spot Seen Glowing - Scientists Get First Look at Weather Inside the Solar System's Biggest Storm

    Science.gov (United States)

    2010-03-01

    New ground-breaking thermal images obtained with ESO's Very Large Telescope and other powerful ground-based telescopes show swirls of warmer air and cooler regions never seen before within Jupiter's Great Red Spot, enabling scientists to make the first detailed interior weather map of the giant storm system linking its temperature, winds, pressure and composition with its colour. "This is our first detailed look inside the biggest storm of the Solar System," says Glenn Orton, who led the team of astronomers that made the study. "We once thought the Great Red Spot was a plain old oval without much structure, but these new results show that it is, in fact, extremely complicated." The observations reveal that the reddest colour of the Great Red Spot corresponds to a warm core within the otherwise cold storm system, and images show dark lanes at the edge of the storm where gases are descending into the deeper regions of the planet. The observations, detailed in a paper appearing in the journal Icarus, give scientists a sense of the circulation patterns within the solar system's best-known storm system. Sky gazers have been observing the Great Red Spot in one form or another for hundreds of years, with continuous observations of its current shape dating back to the 19th century. The spot, which is a cold region averaging about -160 degrees Celsius, is so wide that about three Earths could fit inside its boundaries. The thermal images were mostly obtained with the VISIR [1] instrument attached to ESO's Very Large Telescope in Chile, with additional data coming from the Gemini South telescope in Chile and the National Astronomical Observatory of Japan's Subaru Telescope in Hawaii. The images have provided an unprecedented level of resolution and extended the coverage provided by NASA's Galileo spacecraft in the late 1990s. Together with observations of the deep cloud structure by the 3-metre NASA Infrared Telescope Facility in Hawaii, the level of thermal detail observed from these giant observatories is for the first time comparable to visible-light images from the NASA/ESA Hubble Space Telescope. VISIR allows the astronomers to map the temperature, aerosols and ammonia within and surrounding the storm. Each of these parameters tells us how the weather and circulation patterns change within the storm, both spatially (in 3D) and with time. The years of VISIR observations, coupled with those from the other observatories, reveals how the storm is incredibly stable despite turbulence, upheavals and close encounters with other anticyclones that affect the edge of the storm system. "One of the most intriguing findings shows the most intense orange-red central part of the spot is about 3 to 4 degrees warmer than the environment around it," says lead author Leigh Fletcher. This temperature difference might not seem like a lot, but it is enough to allow the storm circulation, usually counter-clockwise, to shift to a weak clockwise circulation in the very middle of the storm. Not only that, but on other parts of Jupiter, the temperature change is enough to alter wind velocities and affect cloud patterns in the belts and zones. "This is the first time we can say that there's an intimate link between environmental conditions - temperature, winds, pressure and composition - and the actual colour of the Great Red Spot," says Fletcher. "Although we can speculate, we still don't know for sure which chemicals or processes are causing that deep red colour, but we do know now that it is related to changes in the environmental conditions right in the heart of the storm." Notes [1] VISIR stands for VLT Imager and Spectrometer for mid Infrared (eso0417). It is a complex multi-mode instrument designed to operate in the 10 and 20 micron atmospheric windows, i.e. at wavelengths up to about 40 times longer than visible light, and to provide images as well as spectra. More information This research was presented in a paper to appear in Icarus ("Thermal Structure and Composition of Jupiter's Great Red Spot from High-Resolution Thermal Imaging", by L. Fletcher et al.). The team is composed of Leigh N. Fletcher and P. G. J. Irwin (University of Oxford, UK), G. S. Orton, P. Yanamandra-Fisher, and B. M. Fisher (Jet Propulsion Laboratory, California Institute of Technology, USA), O. Mousis (Observatoire de Besançon, France, and University of Arizona, Tucson, USA), P. D. Parrish (University of Edinburgh, UK), L. Vanzi (Pontificia Universidad Catolica de Chile, Santiago, Chile), T. Fujiyoshi and T. Fuse (Subaru Telescope, National Astronomical Observatory of Japan, Hawaii, USA), A.A. Simon-Miller (NASA/Goddard Spaceflight Center, Greenbelt, Maryland, USA), E. Edkins (University of California, Santa Barbara, USA), T.L. Hayward (Gemini Observatory, La Serena, Chile), and J. De Buizer (SOFIA - USRA, NASA Ames Research Center, Moffet Field, CA 94035, USA). Leigh Fletcher was working at JPL during the study. ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and VISTA, the world's largest survey telescope. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the sky".

  1. "This strange process of typing on a glowing glass screen": an interview with Matthew Kirschenbaum

    Directory of Open Access Journals (Sweden)

    Portela, Manuel

    2016-07-01

    Full Text Available Track Changes, by Matthew Kirschenbaum, tells the early history of word processing, roughly situated between 1964—when the IBM Magnetic Tape/Selectric Typewriter (MT/ST was advertised as a word processing system for offices—and 1984—when the Apple Macintosh generalized the graphical user interface in personal computers. The history of word processing both as technological process and mode of textual production is deeply entangled with the changes in the technologies of writing as they reflect and contribute to efficiency and control in increasingly bureaucratic processes of social administration and organization. The literary history of word processing can be situated within this general computerization of the modes of production of writing. Kirschenbaum’s methods combine archival work in special collections and writers’ archives, oral interviews with writers and engineers, and hands-on descriptions of historical word processing machines. Track Changes is the subject of this interview.

  2. Surface modification of polytetrafluoroethylene film using single liquid electrode atmosphericpressure glow discharge

    Institute of Scientific and Technical Information of China (English)

    Zhou Lan; Lü Guo-Hua; Chen Wei; Pang Hua; Zhang Gu-Ling; Yang Si-Ze

    2011-01-01

    Polytetrafluoroethylene films are treated by room temperature helium atmospheric pressure plasma plumes, which are generated with a home-made single liquid electrode plasma device. After plasma treatment, the water contact angle of polytetrafluoroethylene film drops from 114° to 46° and the surface free energy increases from 22.0 mJ/m2 to 59.1 mJ/m2. The optical emission spectrum indicates that there are reactive species such as O2+, O and He in the plasma plume. After plasma treatment, a highly crosslinking structure is formed on the film surface and the oxygen element is incorporated into the film surface in the forms of -C-O-C-, -C=O, and -O-C=O groups. Over a period of 10 days, the contact angle of the treated film is recovered by only about 10°, which indicates that the plasma surface modification is stable with time.

  3. Optimal power flow based on glow worm-swarm optimization for three-phase islanded microgrids

    DEFF Research Database (Denmark)

    Quang, Ninh Nguyen; Sanseverino, Eleonora Riva; Di Silvestre, Maria Luisa

    2014-01-01

    This paper presents an application of the Glowworm Swarm Optimization method (GSO) to solve the optimal power flow problem in three-phase islanded microgrids equipped with power electronics dc-ac inverter interfaced distributed generation units. In this system, the power injected by the distributed...... generation units and the droop control parameters are considered as variables to be adjusted by a superior level control. Two case studies with different optimized parameters have been carried out on a 6-bus test system. The obtained results showed the effectiveness of the proposed approach and overcomes...

  4. Multidimensional Numerical Simulation of Glow Discharge by Using the N-BEE-Time Splitting Method

    Institute of Scientific and Technical Information of China (English)

    Benyssaad KRALOUA; Ali HENNAD

    2012-01-01

    In this work, a new numerical technique is proposed for the resolution of a fluid model based on three Boltzmann moments. The main purpose of this technique is to calculate electric and physical properties in the non-equilibrium electric discharge at low pressure. The transport and Poisson's equations form a self-consistent model. This equation system is written in cylindrical coordinates following the geometric shape of a plasma reactor. Our transport equation system is discretized using the finite volume approach and resolved by the N-BEE explicit scheme coupled to the time splitting method. This programming structure reduces computation time considerably. The 2D code is carried out and tested by comparing our results with those found in literature.

  5. Comparison of glow argon plasma-induced surface changes of thermoplastic polymers

    Science.gov (United States)

    Řezníčková, A.; Kolská, Z.; Hnatowicz, V.; Stopka, P.; Švorčík, V.

    2011-01-01

    Modification of high-density polyethylene (PE), polytetrafluoroethylene (PTFE), polystyrene (PS), polyethyleneterephthalate (PET) and polypropylene (PP) by Ar plasma was studied. The amount of the ablated material was determined by gravimetry. Wettability of polymers after the plasma treatment was determined from the contact angle measurement. The changes in the surface morphology of polymers were observed using atomic force microscopy (AFM). Chemical structure of modified polymers was characterized by X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). Surface changes were also studied by the determination of electrokinetic potential ( ζ-potential). It was found that under the plasma treatment the polymers are ablated and their surface morphology and roughness are changed dramatically. XPS measurements indicate an oxidation of the polymer surface. The plasma treatment results in a dramatic increase of the ζ-potential. EPR data show different radical amount present on the treated surface of all polymers. Most significant changes due to the degradation of polymer chains are observed on PTFE.

  6. Glow in the dark matter: observing galactic halos with scattered light.

    Science.gov (United States)

    Davis, Jonathan H; Silk, Joseph

    2015-02-06

    We consider the observation of diffuse halos of light around the discs of spiral galaxies, as a probe of the interaction cross section between dark matter (DM) and photons. Using the galaxy M101 as an example, we show that for a scattering cross section at the level of 10(-23)(m/GeV)  cm(2) or greater dark matter in the halo will scatter light out from the more luminous center of the disc to larger radii, contributing to an effective increased surface brightness at the edges of the observed area on the sky. This allows us to set an upper limit on the DM-photon cross section using data from the Dragonfly instrument. We then show how to improve this constraint, and the potential for discovery, by combining the radial profile of DM-photon scattering with measurements at multiple wavelengths. Observation of diffuse light presents a new and potentially powerful way to probe the interactions of dark matter with photons, a way that is complementary to existing searches.

  7. 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

  8. Discovery of a glowing millipede in California and the gradual evolution of bioluminescence in Diplopoda.

    Science.gov (United States)

    Marek, Paul E; Moore, Wendy

    2015-05-19

    The rediscovery of the Californian millipede Xystocheir bistipita surprisingly reveals that the species is bioluminescent. Using molecular phylogenetics, we show that X. bistipita is the evolutionary sister group of Motyxia, the only genus of New World bioluminescent millipedes. We demonstrate that bioluminescence originated in the group's most recent common ancestor and evolved by gradual, directional change through diversification. Because bioluminescence in Motyxia has been experimentally demonstrated to be aposematic, forewarning of the animal's cyanide-based toxins, these results are contrary to aposematic theory and empirical evidence that a warning pattern cannot evolve gradually in unpalatable prey. However, gradual evolution of a warning pattern is plausible if faint light emission served another function and was co-opted as an aposematic signal later in the diversification of the genus. Luminescence in Motyxia stem-group taxa may have initially evolved to cope with reactive oxygen stress triggered by a hot, dry environment and was repurposed for aposematism by high-elevation crown-group taxa colonizing new habitats with varying levels of predation. The discovery of bioluminescence in X. bistipita and its pivotal phylogenetic location provides insight into the independent and repeated evolution of bioluminescence across the tree of life.

  9. Glowing graphene quantum dots and carbon dots: properties, syntheses, and biological applications.

    Science.gov (United States)

    Zheng, Xin Ting; Ananthanarayanan, Arundithi; Luo, Kathy Qian; Chen, Peng

    2015-04-08

    The emerging graphene quantum dots (GQDs) and carbon dots (C-dots) have gained tremendous attention for their enormous potentials for biomedical applications, owing to their unique and tunable photoluminescence properties, exceptional physicochemical properties, high photostability, biocompatibility, and small size. This article aims to update the latest results in this rapidly evolving field and to provide critical insights to inspire more exciting developments. We comparatively review the properties and synthesis methods of these carbon nanodots and place emphasis on their biological (both fundamental and theranostic) applications.

  10. dc glow discharge modeling applied to diamond film growth plasma reactors

    Science.gov (United States)

    Surendra, M.; Graves, David B.; Plano, Linda S.

    Low power dc plasmas have been successfully used to grow diamond films. An unusual aspect of these systems is that diamond will only grow at the anode, although most of the plasma-generated species are formed near the cathode. To understand the mechanisms responsible for this phenomenon, and to enhance dc deposition, a model used to describe processes in low neutral gas density dc plasmas has been adapted to diamond-producing dc plasmas. In situ diagnostics were used to supply necessary data for the adaptation and for testing the resulting model. A mechanism for hydrogen dissociation near the anode has been developed. Near the cathode, the most common inelastic process was shown in the model to be ionization. Positive ions are driven by local fields to the cathode and away from the anode. As a result, the cathode is bombarded by ions, which may be responsible for the disruption of diamond growth on this electrode.

  11. Activation energy of thermoluminescence glow curves in a hyperbolic heating scheme

    Energy Technology Data Exchange (ETDEWEB)

    Shambhunath Singh, W. [Manipur College, Imphal (India). Dept. of Physics; Dorendrajit Singh, S.; Mazumdar, P.S. [Manipur Univ. (India). Dept. of Physics; Deb, N.C. [Indian Association for the Cultivation of Science, Calcutta (India). Dept. of Theoretical Physics

    1997-04-07

    We present a set of expressions for the determination of the activation energy of a thermoluminescence peak recorded with a hyperbolic heating scheme. It is demonstrated that the order of kinetics can be estimated from the fractional intensities at the points of inflection of the peak. (author).

  12. Glow in the Dark Matter: Observing galactic halos with scattered light

    CERN Document Server

    Davis, Jonathan H

    2014-01-01

    We consider the observation of diffuse halos of light around the discs of spiral galaxies, as a probe of the interaction cross section between Dark Matter and photons. Using the galaxy M101 as an example, we show that for a scattering cross section at the level of 10^(-23) x (m/GeV) cm^2 or greater Dark Matter in the halo will scatter light out from the more luminous centre of the disc to larger radii, contributing to an effective increased surface brightness at the edges of the observed area on the sky. This allows us to set an upper limit on the DM-photon cross section using data from the Dragonfly instrument. We then show how to improve this constraint, and the potential for discovery, by combining the radial profile of DM-photon scattering with measurements at multiple wavelengths. Observation of diffuse light presents a new and potentially powerful way to probe the interactions of Dark Matter with photons, which is complimentary to existing searches.

  13. Glowing Plants and Living Machines. Towards a Critique of Synthetic Biology

    Directory of Open Access Journals (Sweden)

    Martin Müller

    2016-12-01

    Full Text Available This article criticly engages with 1 synthetic biologys’ technoscientific specifica, 2 the role of biotechnical and biopolitical promises of perfectibility of‚ life itself’, and 3 the problematic notion of ‘digital biology’. Synthetic biology dismisses the idea of an already given nature: ‘life itself’ is conceptualized as a field of potentialities, with adaptable materials and flexible structures that can be used for re-engineering to ‘perfect’ nature. Bioengineers claim to create new living organisms from scratch, using genetically standardized parts and computer-based design: ‘Living machines’ which do not exist in nature are supposed to serve human purposes. Beyond its actual (and limited state of research, some voices of synthetic biology offer bold claims of socio-technical scenarios, imagined objects, and future biotechnical experiments, which take place in society rather than behind laboratory doors. With their visions, synthetic biologists are becoming engineers of future societies. Synthetic biology develops a ‘biotechnologization of collective futures’ and it is part of a technoscientific ‘promise- economy’ that aims on colonizing the future - which demands to rethink Foucaults the question of biopolitics. Crucial for synthetic biologys’ promise of ‘digital biology’ are script-centered, bio-cybernetic, and even transhumanist figures of thought that fuel new visions of ‘life and nature’ as a field of potentials and even limitless treasures that can be programmed and produced by computational procedures: ‘writing’ the code of life.

  14. 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.

  15. Study of a new direct current atmospheric pressure glow discharge in helium

    Energy Technology Data Exchange (ETDEWEB)

    Gielniak, B. [University of Hamburg, Institute for Inorganic and Applied Chemistry, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany); Fiedler, T. [Johannes Gutenberg-University Mainz, Institute for Inorganic and Analytical Chemistry, Duesbergweg 10-14, 55128 Mainz (Germany); Broekaert, J.A.C., E-mail: jose.broekaert@chemie.uni-hamburg.de [University of Hamburg, Institute for Inorganic and Applied Chemistry, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany)

    2011-01-15

    In this study a new DC-APGD operated in He was developed and characterized. The discharge is operated at 0.9 kV and about 25-35 mA and at a gas flow of 100 ml/min. The source was spectroscopically studied and parameters such as the rotational temperature (T{sub rot}), the excitation temperature (T{sub exc}), the ionization temperature (T{sub ion}) and the electron number density (n{sub e}) were determined. The current-voltage characteristic of the source was studied as well. At optimized conditions the discharge operates in the normal region of the current-voltage characteristic. Rotational and excitation temperatures determined with the use of OH band and Fe I lines as thermometric species were of the order of about 900-1200 and 4500-5500 K, respectively. This indicates that despite of the atmospheric pressure, the discharge is not in LTE. Spatially resolved temperature measurements were performed with axial as well as radial resolution and showed relatively flat profiles. Axially resolved emission intensity profiles for several species such as H, N{sub 2}, N{sub 2}{sup +}, OH, He and Hg were determined. It also was found that H{sub 2} introduced into the He by electrolysis of acid solutions such as in ECHG considerably increases the spectroscopically measured gas temperatures but decreases the analyte line intensities, as shown for Hg.

  16. Once-daily NVA237 improves exercise tolerance from the first dose in patients with COPD: the GLOW3 trial

    Directory of Open Access Journals (Sweden)

    Beeh KM

    2012-07-01

    Full Text Available Kai M Beeh,1 Dave Singh,2 Lilla Di Scala,3 Anton Drollmann31insaf Respiratory Research Institute, Wiesbaden, Germany; 2University Of Manchester, Medicines Evaluation Unit, University Hospital of South Manchester, Manchester, UK; 3Novartis Pharma AG, Basel, SwitzerlandIntroduction: Exercise limitation, dynamic hyperinflation, and exertional dyspnea are key features of symptomatic chronic obstructive pulmonary disease (COPD. We assessed the effects of glycopyrronium bromide (NVA237, a once-daily, long-acting muscarinic antagonist, on exercise tolerance in patients with moderate to severe COPD.Methods: Patients were randomized to a cross-over design of once-daily NVA237 50 µg or placebo for 3 weeks, with a 14-day washout. Exercise endurance, inspiratory capacity (IC during exercise, IC and expiratory volumes from spirometry, plethysmographic lung volumes, leg discomfort and dyspnea under exercise (Borg scales, and transition dyspnea index were measured on Days 1 and 21 of treatment. The primary endpoint was endurance time during a submaximal constant-load cycle ergometry test on Day 21.Results: A total of 108 patients were randomized to different treatment groups (mean age, 60.5 years; mean post-bronchodilator, forced expiratory volume in 1 second [FEV1] 57.1% predicted. Ninety-five patients completed the study. On Day 21, a 21% difference in endurance time was observed between patients treated with NVA237 and those treated with placebo (P < 0.001; the effect was also significant from Day 1, with an increase of 10%. Dynamic IC at exercise isotime and trough FEV1 showed significant and clinically relevant improvements from Day 1 of treatment that were maintained throughout the study. This was accompanied by inverse decreases in residual volume and functional residual capacity. NVA237 was superior to placebo (P < 0.05 in decreasing leg discomfort (Borg CR10 scale on Day 21 and exertional dyspnea on Days 1 and 21 (transition dyspnea index and Borg CR10 scale at isotime. The safety profile of NVA237 was similar to that of the placebo.Conclusion: NVA237 50 µg once daily produced immediate and significant improvement in exercise tolerance from Day 1. This was accompanied by sustained reductions in lung hyperinflation (indicated by sustained and significant improvements in IC at isotime, and meaningful improvements in trough FEV1 and dyspnea. Improvements in exercise endurance increased over time, suggesting that mechanisms beyond improved lung function may be involved in enhanced exercise tolerance. (ClinicalTrials.gov Identifier: NCT01154127.Keywords: COPD, dyspnea, FEV1, exercise tolerance, LAMA, NVA237

  17. Glow Discharge Plasma-Assisted Preparation of Nickel-Based Catalyst for Carbon Dioxide Reforming of Methane

    Institute of Scientific and Technical Information of China (English)

    Fang Guo; Wei Chu; Jun-qiang Xu; Lin Zhong

    2008-01-01

    A plasma-assisted method was employed to prepare Ni/γ-Al2O3 catalyst for carbon dioxide reforming of methane reaction. The novel catalyst possessed higher activity and better coke-suppression performance than those of the conventional calcination catalyst. To achieve the same CH4 conversion, the conventional catalyst needed higher reaction temperature, about 50 ℃ higher than that of the N2 plasma-treated catalyst.After the evaluation test, the deactivation rate of the novel catalyst was 1.7%, compared with 15.2% for the conventional catalyst. Different from the characterization results of the calcined catalyst, a smaller average pore diameter and a higher specific surface area were obtained for the plasma-treated catalyst.The variations of the reduction peak temperatures and areas indicated that the catalyst reducibility was promoted by plasma assistance. The dispersion of nickel was also remarkably improved, which was helpful for controlling the ensemble size of metal atoms on the catalyst surface. The modification effect of plasmaassisted preparation on the surface property of alumina supported catalyst was speculated to account for the concentration increase of absorbed CO2. An enhancement of CO2 adsorption was propitious to the inhibition of carbon formation. The coke amount deposited on plasma treated catalyst was much smaller than that on the conventional catalyst.

  18. Frequency-Effects in Capacitively Coupled Radiofrequency Glow-Discharges - a Comparison between Experiments and a 2-Dimensional Fluid Model

    NARCIS (Netherlands)

    Meijer, P. M.; Passchier, J. D. P.; W. J. Goedheer,; Bezemer, J.; van Sark, Wgjhm

    1994-01-01

    The results of a two-dimensional fluid model for argon rf discharges in a closed cylindrical vacuum chamber are compared with experimental data from an amorphous silicon deposition reactor. Good agreement is obtained for the relation between the dc autobias voltage and the dissipated power in the fr

  19. Frequency-Effects in Capacitively Coupled Radiofrequency Glow-Discharges - a Comparison between a 2-D Fluid Model and Experiments

    NARCIS (Netherlands)

    W. J. Goedheer,; Meijer, P. M.; Bezemer, J.; Passchier, J. D. P.; van Sark, Wgjhm

    1995-01-01

    The results of a 2-D fluid model for argon radiofrequency (RF) discharges in a closed cylindrical vacuum chamber are compared with experimental data from an amorphous silicon deposition reactor operated in argon. Good agreement is obtained for the relation between the DC autobias voltage and the dis

  20. Pre-ignition and glow-ignition of gasoline biofuels; Vorentflammung und Gluehzuendung von Ottokraftstoffen mit Bioanteilen

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, Marco; Kremer, Florian; Pischinger, Stefan [RWTH Aachen Univ. (Germany). Lehrstuhl fuer Verbrennungskraftmaschinen; Uygun, Yasar [RWTH Aachen Univ. (Germany). Stosswellenlabor

    2013-12-01

    Due to their specific fuel properties alternative fuels from biomass allow to significantly reduce carbon dioxide emissions and increase the thermal efficiency of gasoline combustion systems. Both enhanced downsizing and new fuels lead to challenges due to irregular combustion phenomena. Within the scope of a FVV research project new test methodologies and possible characteristic numbers characterising irregular combustion phenomena of various alternative fuels have been developed at RWTH Aachen University. (orig.)

  1. Happiness Cools the Warm Glow of Familiarity: Psychophysiological Evidence That Mood Modulates the Familiarity-Affect Link

    NARCIS (Netherlands)

    Vries, M. de; Holland, R.W.; Chenier, T.; Starr, M.J.; Winkielman, P.

    2010-01-01

    People often prefer familiar stimuli, presumably because familiarity signals safety. This preference can occur with merely repeated old stimuli, but it is most robust with new but highly familiar prototypes of a known category (beauty-in-averageness effect). However, is familiarity always warm? Tuni

  2. And yet they glow: thiazole based push-pull fluorophores containing nitro groups and the influence of regioisomerism

    Science.gov (United States)

    Habenicht, Stefanie H.; Siegmann, Michael; Kupfer, Stephan; Kübel, Joachim; Weiß, Dieter; Cherek, Doreen; Möller, Uwe; Dietzek, Benjamin; Gräfe, Stefanie; Beckert, Rainer

    2015-06-01

    Reported is a study on the influence of regioisomerism on the photophysical properties in 4-hydroxy-1,3-thiazole-based push-pull-chromophores/fluorophores to evaluate the molecular structure-property relationship as a basic foundation for future design strategies concerning this class of dyes. Surprisingly, the nitro groups used as acceptors do not act as a fluorescence quencher, instead the derivatives synthesized exhibit quantum yields of 37-40%. Two 4-ethoxy-1,3-thiazole derivatives which differ only in the positioning of their electron donating (methoxy) and electron withdrawing (nitro) groups have been synthesized and examined in terms of their photophysical properties, i.e. UV/Vis absorption and fluorescence emission spectra. Additionally, quantum chemical calculations have been performed to unravel the underlying fundamental transitions and to explain the experimental results.

  3. Calorimetric study of the thermal induced transformations of ultrafine silicon carbide powder produced by RF glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Costa, J.; Sunol, J.J.; Saurina, J.; Roura, P. [Girona Univ. (Spain). Dept. d`Enginyeria Industrial; Viera, G.; Bertran, E. [Dept. de Fisica Aplicada i Electronica, Facultat de Fisica, Univ. de Barcelona (Spain); Martinez, S. [Dept. de cristallografia mineral i diposits minerals, Univ. de Barcelona (Spain)

    1997-12-31

    Nanometric powder of silicon carbide has been produced by plasma-enhanced chemical vapor deposition (PECVD) in a radiofrequency discharge of silane and methane gas mixtures. The as deposited powders consists of amorphous particles which are highly hydrogenated. We will show in this communication, that the powder structure can be improved by thermal annealing at high temperatures. The structural changes have been analyzed by several techniques such as thermal desorption of hydrogen (TDSH), differential scaning calorimetry (DSC), infrared spectroscopy (IR) and transmission electron microscopy (TEM). The kinetic parameters of processes such as Si-H and C-H bond breaking have been determined. After annealing, the particles are crystalline, hydrogen free and do not suffer room temperature oxidation. (orig.) 8 refs.

  4. Artificial cornea: surface modification of silicone rubber membrane by graft polymerization of pHEMA via glow discharge.

    Science.gov (United States)

    Lee, S D; Hsiue, G H; Kao, C Y; Chang, P C

    1996-03-01

    A method for producing various surfaces of silicone rubber membrane (SR) was developed in this study by grafting various amounts of poly(2-hydroxy ethyl methacrylate) (pHEMA) onto SR by plasma-induced grafted polymerization (PIP) as a homobifunctional membrane. The elemental composition and different carbon bindings on the surface of SR were examined by electron spectroscopy for chemical analysis with the amount of O1s/C1s being approximately 0.7 at 1 min, 60 W, 200 mTorr of Ar-plasma treatment. The peroxide group introduced on SR was measured via 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the amount of 6.85 x 10(-8) mol cm-2 reached optimum value at 1 min of Ar-plasma treatment. After Ar-plasma treated SR, the peroxide group (33D peak) was introduced on the surface of SR by negative spectra of secondary ion mass spectroscopy analysis, whereas ester groups (72D peak) were observed for pHEMA-grafted SR. For the in vitro test, the influence of various surfaces of SR on attachment and growth of rabbit corneal epithelial cells (CEC) was studied by cell culture assay. These results indicated that 56-150 micrograms cm-2 of pHEMA grafted onto SR were suitable values for attachment and growth of CEC. On the contrary, the large grafted amounts (500-1650 micrograms cm-2) of pHEMA on SR were insufficient for attachment and growth of CEC. For the in vivo test, the migration of CEC from host cornea to implant was investigated by slit lamp microscopy. The experimental results indicated that SRs grafted with pHEMA were completely covered with CEC 3 weeks after implantation of the membranes into the host cornea. These results provide a valuable reference for developing an artificial cornea.

  5. Trapped ions and the shielding of dust particles in low-density non-equilibrium plasma of glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Sukhinin, Gennady; Fedoseev, Alexander [Institute of Thermophysics SB RAS, Ave. Lavrentyev, 1, Novosibirsk 630090 (Russian Federation); Antipov, Sergei; Petrov, Oleg; Fortov, Vladimir [Joint Institute for High Temperatures RAS, Izhorskaya 13/19, Moscow 127412 (Russian Federation)], E-mail: sukhinin@itp.nsc.ru

    2009-05-29

    A new model for the formation of trapped ions around a negatively charged dust particle immersed in low-density non-equilibrium plasma of gas discharge is presented. It is shown that the ionic coat leads to a shielding of the proper charge of the dust particle. In experiments it is only possible to detect the effective charge of a dust particle that is equal to the difference between the proper charge of the particle and the charge of trapped ion000.

  6. ANALISA SPEKTROSKOPI EMISI UNTUK PENENTUAN TEMPERATUR ELEKTRONIK PADA PLASMA NON-TERMIK NITROGEN

    Directory of Open Access Journals (Sweden)

    Muhammad Nur

    2012-02-01

    Full Text Available Suatu metoda baru telah dikembangkan untuk penentuan temperatur elektronik dari plasma non-termik nitrogen dengan menggunakan spektroskopi emisi. Metoda ini telah dipakai untuk plasma non-termik nitrogen yang diproduksi dalam lucutan pijar korona densitas tinggi. Dengan mengasumsikan bahwa fungsi distribusi energi dari elektron adalah distribusi  maxwellian dan penggunaan data tampang lintang efektif dari sistem positif kedua, 2s+, (C3Pu®B3Pg dari N2 dan sistem negatif pertama, 1s– (B2S+u®X2S+g  dari N2+, hubungan antara energi rerata elektron dengan perbandingan intensitas 1s–(0-0 dan intensitas 2s+(2-5 dapat diselesaikan ecara teoretik. Spektrum emisi dari molekul nitrogen tereksitasi, (C3Pu®B3Pg dari N2 dan molekul terionisasi, 1s– (B2S+u®X2S+g dari N2+, secara eksperimen diperoleh dari spektroskopi emisi. Melalui identifikasi dan analisa spektru-spektrum tersebut, perbandingan intensitas 1s–(0-0 dan intensitas 2s+(2-5 diperoleh secara eksperimen. Metoda ini telah diterapkan untuk menentukan energi rerata elektron atau temperatur elektronik dari plasma non termik nitrogen dalam lucutan pijar korona dengan densitas dari 2,4 x 1020 cm-3 sampai 9,2 x 1020 cm-3

  7. Tailoring Surface Properties of Polymeric Separators for Lithium-Ion Batteries by 13.56 MHz Radio-Frequency Plasma Glow Discharge

    Science.gov (United States)

    Liang, Chia-Han; Juang, Ruey-Shin; Tsai, Ching-Yuan; Huang, Chun

    2013-11-01

    The hydrophilic surface modification of the polymeric separator is achieved by low-pressure 13.56 MHz radio-frequency Ar and He gas plasma treatments. The changes in surface hydrophilicity and surface free energy were examined by static contact angle analysis. The static water contact angle of the plasma-modified polymeric separator particularly decreased with the increase in treatment time. An obvious increase in the surface energy of polymeric separators owing to the crosslinking by activated species of inert gases effect of monatomic-gas-plasma treatments was also observed. Optical emission spectroscopy was carried out to analyze the chemical species generated after Ar and He gas plasma treatments. The variations in the surface morphology and chemical structure of the polymeric separators were confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS) measurements. XPS analysis showed significantly higher surface concentrations of oxygen functional groups for monatomic-gas-plasma-modified polymeric separator surfaces than for the unmodified polymeric separator surface. The experimental results show the important role of chemical species in the interaction between Ar and He gas plasmas and the polymeric separator surface, which can be controlled by surface modification to tailor the hydrophilicity of the polymeric separator.

  8. Glow Discharge Plasma Treatment of Carmoisine%辉光放电等离子体处理酸性红染料废水

    Institute of Scientific and Technical Information of China (English)

    翁棣; 黄小洋; 赵剑波; 李争光; 翟国庆

    2013-01-01

    以酸性红染料水溶液为模拟废水,考察了污染物初始浓度、电流、电压和溶液体积等实验参数对酸性红染料辉光放电等离子体降解的影响.实验用辉光放电等离子体技术对酸性红AR73的降解进行了研究,借助紫外分光光度法来分析分解过程中的酸性红染料浓度的变化.在不同电压、电流的条件下,分解速率随电压电流增大而加快;调节pH后研究了酸碱性对染料废液的处理效果;通过添加一些在其他有机废水处理中有效果的催化剂TiO2和Fe3+研究其对酸性红的催化效果.

  9. Heterogeneous sono-Fenton-like process using nanostructured pyrite prepared by Ar glow discharge plasma for treatment of a textile dye.

    Science.gov (United States)

    Khataee, Alireza; Gholami, Peyman; Vahid, Behrouz

    2016-03-01

    The plasma-treated pyrite (PTP) nanostructures were prepared from natural pyrite (NP) utilizing argon plasma due to its sputtering and cleaning effects resulting in more active surface area. The NP and PTP were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) and scanning electron microscopy (SEM) methods. The performance of the PTP was greater than NP for treatment of Reactive Red 84 (RR84) by the heterogeneous sono-Fenton process. The optimum amounts of main operational parameters were obtained as PTP of 4 g/L, initial dye concentration of 10 mg/L, pH of 5, and ultrasonic power of 300 W after 120 min of reaction time. Also, the effects of enhancers, and inorganic salts and t-butanol as hydroxyl radical scavengers on the degradation efficiency were investigated. Gas chromatography-mass spectroscopy analysis (GC-MS) was applied for detection of some degradation intermediates. Environmentally friendly plasma modification of the NP, in situ production of H2O2 and OH radicals, low leached iron concentration and repeated reusability at the milder pH are the significant benefits of the PTP utilization.

  10. Research Advances: Perchlorate in Dairy and Breast Milk Samples; NO Glow on Mars; Physical Chemistry to the Rescue: Differentiating Nicotinic and Cholinergic Agonists

    Science.gov (United States)

    King, Angela G.

    2005-07-01

    Perchlorate levels in milk suggest widespread presence of the chemical. NO emissions indicate circulation in Martian atmosphere. Modeling reveals subtle differences in drug membrane receptor interactions.

  11. Generation of amphoteric surfaces via glow-discharge technique with single precursor and the behavior of bovine serum albumin at the surface.

    Science.gov (United States)

    Akdoğan, Ebru; Mutlu, Mehmet

    2012-01-01

    Amphoteric surfaces were generated on silicone substrates via plasma polymerization technique using a single monomer; diethyl allyl phosphate (DAP). Surface characterization was performed by the means of contact angle titration and Fourier transform infrared (FTIR) spectroscopy. The surface of silicone was found to be slightly basic with an apparent basicity of 0.12 μmol/m(2) while plasma surface modification made the surfaces amphoteric with the surface acid/base concentration adjustable by varying plasma parameters. The adsorption of model protein; bovine serum albumin (BSA) on the surfaces was found to be correlated to the surface acid/base ratio. Percent reduction on modified surfaces compared to bare silicone surface was 32, 59 and 92% for 20 W 5 min, 60 W 5 min and 100 W 5 min modified surfaces respectively. Conformational change of BSA upon adsorption to the surfaces was investigated with FTIR-ATR spectroscopy. It has been shown that BSA preserves more of its secondary structure upon adsorption to plasma modified surfaces than the bare silicone surface. It has been concluded that DAP modified surfaces reduces the amount of protein adsorption on the surfaces due to the modified surfaces amphoteric nature and the ability of modified surfaces to preserve the secondary structure of adsorbed protein better than the bare silicone surface.

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

    OpenAIRE

    Borowski, Tomasz; Ossowski, Maciej (OPI); Kowalczyk, Piotr; Maciej DUBEK; Agnieszka BROJANOWSKA; Krzysztof ROŻNIATOWSKI

    2016-01-01

    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 require...

  13. Glowing seashells: diversity of fossilized coloration patterns on coral reef-associated cone snail (Gastropoda: Conidae shells from the Neogene of the Dominican Republic.

    Directory of Open Access Journals (Sweden)

    Jonathan R Hendricks

    Full Text Available The biology of modern Conidae (cone snails--which includes the hyperdiverse genus Conus--has been intensively studied, but the fossil record of the clade remains poorly understood, particularly within an evolutionary framework. Here, ultraviolet light is used to reveal and characterize the original shell coloration patterns of 28 species of cone snails from three Neogene coral reef-associated deposits from the Cibao Valley, northern Dominican Republic. These fossils come from the upper Miocene Cercado Fm. and lower Pliocene Gurabo Fm., and range in age from about 6.6-4.8 Ma. Comparison of the revealed coloration patterns with those of extant species allow the taxa to be assigned to three genera of cone snails (Profundiconus, Conasprella, and Conus and at least nine subgenera. Thirteen members of these phylogenetically diverse reef faunas are described as new species. These include: Profundiconus? hennigi, Conasprella (Ximeniconus ageri, Conus anningae, Conus lyelli, Conus (Atlanticonus? franklinae, Conus (Stephanoconus gouldi, Conus (Stephanoconus bellacoensis, Conus (Ductoconus cashi, Conus (Dauciconus garrisoni, Conus (Dauciconus? zambaensis, Conus (Spuriconus? kaesleri, Conus (Spuriconus? lombardii, and Conus (Lautoconus? carlottae. Each of the three reef deposits contain a minimum of 14-16 cone snail species, levels of diversity that are similar to modern Indo-Pacific reef systems. Finally, most of the 28 species can be assigned to modern clades and thus have important implications for understanding the biogeographic and temporal histories of these clades in tropical America.

  14. Conversion of a Micro, Glow-Ignition, Two-Stroke Engine from Nitromethane-Methanol Blend Fuel to Military Jet Propellant (JP-8)

    Science.gov (United States)

    2012-01-01

    section of air intake assembly solid model; shows hot-wire anemometer probe orientation and venturi shape [25...it the weak link. Added machined flat to motor shaft and a #6-32 UNC cup -point setscrew to coupler on motor end. 2 Coupler spins up threaded...engine shaft Having fixed the motor end, engine end became the weak link. Added machined flat to engine shaft and a #8-32 UNC cup -point setscrew

  15. Aplikasi Metode Lean Six Sigma Untuk Usulan Improvisasi Lini Produksi Dengan Mempertimbangkan Faktor Lingkungan. Studi Kasus: Departemen GLS (General Lighting Services PT. Philips Lighting Surabaya

    Directory of Open Access Journals (Sweden)

    Miftachul Arifin

    2012-09-01

    Full Text Available Departemen GLS (General Lighting Services PT. Philips Lighting Surabaya merupakan produsen lampu pijar. Pada pelaksanaan proses produksinya, perusahaan menemui beberapa kendala yang terkait dengan waste. Analisis lean six sigma dengan menggunakan value stream mapping menunjukkan terjadi defect di mesin finishing dan waiting di mesin mounting. EHS waste juga muncul yang mengindikasikan adanya dampak terhadap lingkungan dan kesehatan serta keselamatan pekerja. Pencarian akar permasalahan dilakukan dengan menggunakan tools RCA (5 whys dan FMEA hingga memunculkan 15 penyebab utama terjadinya ketiga waste tersebut. Pembentukan tim Total productive maintenance, penelitian perbaikan kualitas bulb dan flare, serta eksperimen pengurangan jumlah jenis coil menjadi usulan alternatif yang bisa dilakukan perusahaan. Dengan menggunakan konsep value management didapatkan alternatif terbaik dengan melakukan pembentukan dan pelatihan tim Total productive maintenance. Alternatif ini meningkatkan nilai sigma defect dari 2,92 menjadi 3,08 dan sigma waiting dari 2,83 menjadi 2,89. Indikator dampak lingkungan juga mengindikasikan penurunan yang sejalan.

  16. Pengembangan Kuliah Eksperimen Fisika dengan Teknologi Multimedia

    Directory of Open Access Journals (Sweden)

    Okimustava Okimustava

    2014-04-01

    Full Text Available Penelitian tentang pembelajaran berbasis lesson study untuk mata kuliah eksperimen fisika yang bertujuan untuk meningkatkan proses pembelajaran eksperimen fisika dengan dua jenis media instruksional berbasis teknologi multimedia, yaitu Video Based Laboratory (VBL dan Simulation Based Laboratory (SBL. Lesson study merupakan kegiatan pembelajaran dengan kegiatan perencanaan (plan, implementasi pembelajaran (do dan observasi serta refleksi (see terhadap perencanaan dan implementasi pembelajaran. Topik eksperimen yang diberikan adalah Efek Fotolistrik, Watak Lampu Pijar, Gerak Harmonik Sederhana dan Verifkasi Hukum Kekekalan Momentum. Evaluasi kemampuan mahasiswa setelah pembelajaran meliputi evaluasi kongitif dengan tes konseptual tentang penguasaan materi fisika dan tes essay tentang kemampan analisis data eksperimental fisika, dan evaluasi keterampilan kerja ilmiah dengan membuat makalah dan poster ilmiah dari topik eksperimen yang dilakukan. Hasil penelitian bahwa pembelajaran berbasis lesson study pada mata kuliah eksperimen fisika menggunakan VBL dan SBL dapat meningkatkan kemampuan konseptual dan keterampilan mahasiswa.

  17. 霓虹灯中氦、氖、氩气体辉光放电分析及PIC模拟%Analysis and the PIC simulation of the glow discharge of the neon lamp, neon, argon and helium

    Institute of Scientific and Technical Information of China (English)

    王维; 邓明; 王世平; 罗亮; 周筑文

    2015-01-01

    通过对霓虹灯中的惰性气体氦、氖、氩气体进行直流辉光放电研究,结合等离子体粒子模拟实验(PIC),模拟分析了氯(He)、氖(Ne)、氩(Ar)在直流高电压、低气压下的直流辉光放电过程.通过模拟实验分析和阐述了He、Ne、Ar电离后各种离子、电子、二次电子的动能、密度以及空间能量分布.分析这些物理参量,能合理地解释霓虹灯中的惰性气体氦、氖、氩的直流辉光放电现象,在一定程度上,为各种填充气体的霓虹灯工艺提供了一定的理论参考.

  18. The Effect of Water Acrylate Dispersion on the Properties of Polymer-Carbon Nanotube Composites / Wpływ Wodnej Dyspersji Akrylanowej Na Właściwości Kompozytów Polimer-Nanorurki Węglowe

    Directory of Open Access Journals (Sweden)

    Zygoń P.

    2015-12-01

    Full Text Available The paper presents properties of polymer composites reinforced with carbon nanotubes (CNT containing various mixtures of dispersion. Acrylates of different particle size and viscosity were used to produce composites. The mechanical strength of composites was determined by three-point bending tests. The roughness parameter of composites was determined with a profilometer and compared with the roughness parameter determined via atomic force microscopy (AFM. Also X-ray studies (phase composition analysis, crystallite sizes determination were carried out on these composites. Measurements of the surface topography using the Tapping Mode method were performed, acquiring the data on the height and on the phase imaging. The change of intensity, crystallite size and half-value width of main reflections originating from carbon within the composites have been determined using the X-ray analysis. The density of each obtained composite was determined as well as the resistivity at room temperature. The density of composites is quite satisfactory and ranges from 0.27 to 0.35 g/cm3. Different composites vary not only in strength but also in density. Different properties were achieved by the use of various dispersions. Carbon nanotubes constituting the reinforcement for a polymer composite improve the mechanical properties and conductivity composite.

  19. Preparation of Copper-Cobalt Catalyst by Glow Discharge Plasma for Lower Alcohols Synthesis%射频等离子体技术制备合成低碳醇用铜钴基催化剂

    Institute of Scientific and Technical Information of China (English)

    徐慧远; 储伟; 士丽敏; 张辉; 周俊

    2008-01-01

    采用射频等离子体技术制备了CO加氢合成低碳醇用新型CuCo/ZrO2催化剂,研究了等离子体气氛氮气、氢气和先氮气后氢气处理对催化剂结构和性能的影响,并应用BET、XRD、XPS、TG和TPR技术对催化剂进行了表征.与常规焙烧制得的样品相比,射频等离子体技术制备的催化剂可有效抑制烃类生成,提高总醇选择性,大幅提高反应活性和低碳醇的时空收率.表征结果显示,等离子体技术使催化剂前驱体在低温下分解形成活性相,显著提高了催化剂比表面积,促进催化剂活性组分晶粒细化并提高其分散度,催化剂表面的铜含量增加.

  20. Effect of glow discharge plasma on copper-cobalt-aluminum catalysts for higher alcohol synthesis%射频等离子体对合成低碳醇用CuCoAl催化剂的改性作用

    Institute of Scientific and Technical Information of China (English)

    徐慧远; 储伟; 士丽敏; 张辉; 邓思玉

    2009-01-01

    采用共浸渍法制备了CuCo/γ-Al2O3催化剂,应用射频等离子体技术对催化剂进行改性处理.以CO加氢合成低碳醇为模型反应对催化剂进行活性评价,通过X射线物相分析(XRD)、氢氧滴定(HOT)、CO程序升温脱附(CO-TPD)和程序升温还原(TPR)等技术对催化剂进行表征,研究了射频等离子体技术强化处理对催化剂结构、吸附性能和还原性能的影响.结果表明,等离子体技术改性处理提高了催化剂活性组分的分散度,细化了铜物种的晶粒尺寸,增加反应活性位并调变了活性位对吸附物种的吸附强度,改进了催化剂的还原性能,等离子体改性处理的催化剂比未处理的样品CO加氢反应活性和低碳醇的时空产率显著提高.

  1. 大气压辉光放电液相沉积装置在表面改性中的应用%Application of Device of Atmospheric Pressure Glow Discharge Liquid Deposition in Surface Modification

    Institute of Scientific and Technical Information of China (English)

    蒋晓梅; 芮延年; 陈国强; 王红卫; 陈银

    2009-01-01

    用高频高压电源、介质阻挡放电装置及惰性气体氦(He)产生大气压辉光放电等离子体,超声喷嘴喷射雾状液滴直接送入等离子体区域,喷洒在处理物表面上,进行等离子体接枝聚合.应用这套装置对PE纤维进行处理,选择甲基丙烯酸十二氟庚酯DFMA(C11H8F12O2)作为液相单体,对不同处理参数下PE纤维表面的接触角和接枝率变化进行了规律性和原理分析,用IR、SEM和EDS分析了处理前后PE纤维表面的变化.实验结果表明,在PE纤维表面成功引入了疏水性基团,提高了其疏水性.

  2. A study of the application of photoelectric pyrometer thermometry to a double glow plasma surface alloying process%光电高温计在双辉等离子渗金属测温中的应用研究

    Institute of Scientific and Technical Information of China (English)

    池成忠; 贺志勇; 徐重

    2003-01-01

    为准确测量双辉等离子渗金属中的工件温度,借助自行研制的一套热电偶测温实验装置,采用比对实验的手段,得出了在碳钢表面常规双辉等离子渗金属过程中,准确选定光电高温计的材料发射率修正系数的方法.

  3. Thermocou;oe Thermometry in Double Glow Plasma Surface Alloying Process%双层辉光等离子体渗金属中的热电偶测温

    Institute of Scientific and Technical Information of China (English)

    池成忠; 高原; 徐重

    2002-01-01

    分析比较了几种应用在双层辉光等离子体渗金属中的测温手段存在的问题,采用阴极屏蔽技术,研制出一套适合双层辉光等离子体渗金属工件热电偶测温的实验装置,并介绍了其结构和工作原理.实验结果表明,该装置工作稳定,安全可靠,也可用于其它类似工况中的温度测量.

  4. Analysis on Lissajous Figures of Dielectric Barrier Glow Discharge in Atmospheric-pressure Helium%大气压下氦气介质阻挡辉光放电过程的Lissajous图形分析

    Institute of Scientific and Technical Information of China (English)

    郝艳捧; 刘耀阁; 郑彬

    2012-01-01

    In order to investigate the variation of equivalent capacitance during dielectric barrier discharge (DBD), single pulse and multi-pulse discharges were obtained using a high-frequency power supply in atmospheric-pressure helium. By measuring applied voltage and loop current, Lissajous figures were calculated and compared with those which were directly measured. The equivalent capacitance of the gas gap and dielectrics during the discharging and cutting-off phases were calculated with the corresponding relationship between the peaks and valleys of current pulse and the points on Lissajous figures. The reasons of variation of the equivalent capacitance were analyzed, and the physical process of discharge was discussed. The results show that the equivalent capacitance can be studied by using calculated Lissajous figures instead of the measured ones. The equivalent capacitance keeps unchanged during the discharge cutting-off stage, but changes with current during the discharging stage and reaches its maximum at the peak point of current pulse. And the process of discharge is mainly affected by the changing rates of applied voltage and space charges.%为研究介质阻挡放电(DBD)过程中等效电容的变化情况,利用高频高压电源,进行了大气压氦气介质阻挡单脉冲和多脉冲辉光放电试验,利用外施电压、回路电流计算得到放电Lissajous图形,并与直接测量的Lissajous图形进行了对比。确定了放电电流波峰和波谷在Lissajous图形上的对应位置,计算了放电截止和放电进行阶段气隙和介质的等效电容,分析了等效电容变化的原因,并且探讨了放电的物理过程。结果表明:计算得到的Lissajous图形与测量所得的Lissajous图形一致;介质等效电容在放电截止阶段保持不变,但在放电进行阶段随电流脉冲变化而变化,并且在电流峰值处最大;放电物理过程主要受到外施电压和介质表面电荷量的变化速率影响。

  5. Preparation of polymer cement long after glow energy storage luminescence coating%聚合物水泥长余辉蓄能发光涂料的制备

    Institute of Scientific and Technical Information of China (English)

    张金安

    2004-01-01

    以硝酸铝、硝酸锶、氧化铕、氧化镝为原料,用溶胶凝胶法合成了稀士铝酸锶长余辉发光材料:SrAl2O4:Eu2+,Dy3+.以核一壳结构聚丙烯酸酯乳液为主要成膜物,添加铝酸锶发光粉、白水泥及助剂制成聚合物水泥长余辉蓄能发光涂料.测定了发光涂料性能,涂料余辉亮度高、余辉时间长、施工性能好、粘结强度高、耐候性优良.

  6. Inkjet printing of polyester fabric modified with radio frequency glow discharge%射频辉光放电改性涤纶织物的喷墨印花

    Institute of Scientific and Technical Information of China (English)

    王春莹; 章维

    2009-01-01

    采用射频辉光放电技术对涤纶春亚纺织物进行表面改性处理,再用浅品色纳米颜料墨水进行喷墨印花,探讨射频辉光放电处理条件对涤纶春亚纺织物的润湿性、喷墨打印效果、透湿性能及织物表面生成官能团的影响.结果表明,射频辉光放电处理后,涤纶春亚纺织物的润湿性、防渗化性能和透湿性能显著提高,喷墨印花图案清晰、得色量提高;织物表面没有新的官能团形成,分散染料的染色性能没有明显变化.

  7. Modeling High Pressure Micro Hollow Cathode Discharges

    Science.gov (United States)

    2007-11-02

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

  8. A fading-based method for checking the presence of closely overlapping peaks in thermoluminescent (TL) materials

    Science.gov (United States)

    Furetta, C.

    The paper describes a method, based on fading experiment, for determining the presence of a complex structure in the thermoluminescent glow curve emission from herbs, e.g. oregano and nopal. Because of the polymineral content of the inorganic part of these herbs, the emitted glow curve is the result of several overlapping glow peaks, each one corresponding to another mineral. The initial rise method is also used for determining the activation energy of each component.

  9. Increased annoyance from illuminance of greenhouses in areas not familiar with greenhouses

    NARCIS (Netherlands)

    Oel, C. van; Janssen, E.G.O.N.; Alferdinck, J.W.A.M.; Ruigrok, J.

    2007-01-01

    Many greenhouses use artificial light to grow plants, causing visible sky glow. Initially, low density growth lights were used. With the introduction of high density grow lights, the sky glow luminance of greenhouses has considerably risen. In the urbanized western parts of Holland, old warehouses a

  10. FLEET for Unseeded Velocity Measurements in All Speed Regimes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — FLEET uses a 100 fs laser to excite a multi-photon process that makes the gas (N2 or air) glow.  Images of the glowing gas taken at set time intervals allow the...

  11. Lead-Tungstate Crystal of the ALICE Photon Spectrometer (PHOS)

    CERN Multimedia

    2003-01-01

    The photon spectrometer (PHOS) is designed to measure the temperature of collisions by detecting photons emerging from them. It will be made of lead tungstate crystals like these. When high-energy photons strike lead tungstate, they make it glow, or scintillate, and this glow can be measured. Lead tungstate is extremely dense (denser than iron), stopping most photons that reach it.

  12. Microwave Synthesis of a Long-Lasting Phosphor

    Science.gov (United States)

    Filhol, Jean-Sebastien; Zitoun, David; Bernaud, Laurent; Manteghetti, Alain

    2009-01-01

    Efficient glow-in-the-dark materials are usually difficult to synthesize and need complex experiments with long reaction times that are not appropriate for conventional lab teaching. Therefore, we describe a new experimental procedure that allows the production of one of the most efficient "glow-in-the-dark" materials (SrAl[subscript 2]O[subscript…

  13. Characterizing uniform discharge in atmospheric helium by numerical modelling

    Institute of Scientific and Technical Information of China (English)

    Lü Bo; Wang Xin-Xin; Luo Hai-Yun; Liang Zhuo

    2009-01-01

    One-dimensional fluid model of dielectric barrier discharge (DBD) in helium at atmospheric pressure was estab-lished and the discharge was numerically simulated. It was found that not only the spatial distributions of the internal parameters such as the electric field, the electron density and ion density are similar to those in a low-pressure glow discharge, but also the visually apparent attribute (light emission) is exactly the same as the observable feature of a low-pressure glow discharge. This confirms that the uniform DBD in atmosphcric helium is a glow type discharge. The fact that the thickness of the cathode fall layer is about 0.5 ram, much longer than that of a normal glow dischargc in helium at atmospheric pressure, indicates the discharge being a sub-normal glow discharge close to normal one. The multipulse phenomenon was reproduced in the simulation and a much less complicated explanation for this phenomenon was given.

  14. Thermoluminescence properties of irradiated chickpea and corn

    Science.gov (United States)

    Necmeddin Yazici, A.; Bedir, Metin; Bozkurt, Halil; Bozkurt, Hüseyin

    2008-02-01

    A study was carried out to establish a detection method for irradiated chickpea and corn by thermoluminescence (TL) method. The leguminous were packed in polyethylene bags and then the packets were irradiated at room temperature at different doses by 60Co gamma source at 1, 4, 8 and 10 kGy. Minerals extracted from the leguminous were deposited onto a clean aluminum disc and TL intensities of the minerals were measured by TL. It was observed that the extracted samples from both leguminous exhibit good TL Intensity and the TL intensity of glow curves of them increased proportionally to irradiation doses. The TL glow curve of both irradiated leguminous presents a single broad peak below 400 °C. The TL trapping parameters glow peaks were estimated by the additive dose (AD), Tm(Ea)-Tstop and computerized glow curve deconvolution (CGCD) methods. The fading characteristics of glow curves were also recorded up to 6 months.

  15. Trials to identify irradiated chestnut (Castanea bungena) with different analytical techniques

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.-W. E-mail: chunghw@kfda.go.kr; Delincee, Henry; Han, S.-B.; Hong, J.-H.; Kim, H.-Y.; Kim, M.-C.; Byun, M.-W.; Kwon, J.-H

    2004-10-01

    Photostimulated luminescence (PSL) measurement, DNA comet assay, electron spin resonance (ESR) spectroscopy and thermoluminescence (TL) measurement were applied to identify irradiated chestnut. Samples were irradiated with {sup 60}Co {gamma}-rays at 0-0.5 kGy. The PSL photon counts for irradiated chestnuts were too low to be distinguished from those of the non-irradiated sample. There was no difference in DNA comets between non-irradiated and irradiated chestnuts. ESR spectroscopy did not show any radiation-induced specific signals but a symmetric singlet. However, using TL, the shape of the glow curve (Glow 1) made it possible to identify the irradiated chestnuts. In addition, the TL glow ratio (Glow 1/Glow 2) obtained by normalization was less than 0.01 for the non-irradiated sample and {>=}0.10 for irradiated ones, respectively.

  16. Room-temperature effects of UV radiation in KBr:Eu{sup 2+} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Salas, R.; Melendrez, R. [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada - IFUNAM, Ensenada, Apartado Postal 2732 Ensenada, BC, 22800 (Mexico); Aceves, R.; Rodriguez, R.; Barboza-Flores, M. [Centro de Investigacion en Fisica, Universidad de Sonora, Apartado Postal 5-088 Hermosillo, Sonora, 83190 (Mexico)

    1996-07-01

    Thermoluminescence and optical absorption measurements have been carried out in KBr:Eu{sup 2+} crystals irradiated with monochromatic UV light (200-300 nm) and x-rays at room temperature. For UV- and x-irradiated crystals strong similarities between the thermoluminescence glow curves have been found, suggesting that the low-energy UV radiation produces the same defects as produced by x-irradiation in this material. The thermoluminescence glow curves are composed of six glow peaks located at 337, 383, 403, 435, 475 and 509 K. Thermal annealing experiments in previously irradiated crystals show clearly a correlation between the glow peak located at 383 K and the F-centre thermal bleaching process. Also, the excitation spectrum for each thermoluminescence glow peak has been investigated, showing that the low-energy radiation induces the formation of F centres. (author)

  17. 双辉多元共渗与电刷镀复合表面耐蚀渗镀层的研究%A STUDY OF THE CORROSION RESISTING COMPOSITE ALLOYING LAYER OBTAINED BY DOUBLE GLOW PLASMA WITH BRUSH PLATING Ni INTERLAYER

    Institute of Scientific and Technical Information of China (English)

    徐江; 谢锡善; 徐重; 董世运; 徐滨士

    2002-01-01

    在20钢表面电刷镀快速Ni层作为过渡层,然后采用双层辉光离子技术将Ni-Cr-Mo-Cu合金进行多元共渗,对形成的复合镀层在5%HCl溶液中进行了电化学腐蚀性能测试.利用XRD,扫描电镜以及EDX对渗层的组织结构和合金元素及碳元素在渗层中的分布进行了分析.结果表明:预先刷镀快速Ni镀层再进行双层辉光多元渗Ni Cr-Mo-Cu的复合渗镀层的耐蚀性能明显优于双辉多元渗Ni-Cr-Mo Cu以及单独电刷镀Ni镀层的耐蚀性能.分析认为,由于双辉多元共渗中的温度效应,使刷镀的Ni镀层与20钢基材之间互扩散,有效地降低渗镀层中的碳含量,从而使多元共渗Ni-Cr-Mo-Cu与刷镀的Ni镀层双层复合渗镀层具有较好的耐蚀性能.

  18. 利用直流辉光放电等离子体改善聚氯乙烯细管内表面亲水性的研究%On the improvement of hydrophilicity of inner surface of PVC tube by DC glow discharge plasma

    Institute of Scientific and Technical Information of China (English)

    刘雪华; 温小琼; 汪俊; 刘贵师

    2009-01-01

    采用低气压氩气直流辉光放电等离子体对PVC细管内表面进行了处理,使其内表面亲水性得到显著改善,且处理效果均匀.处理时间越长PVC细管内表而的水接触角越小.经过处理后的PVC细管放置室内大气环境后内表面的水接触角出现退化,72小时以后基本稳定,稳定后的内表面水接触角显著好于未经处理的PVC细管.

  19. 微波和等离子体辅助次氯酸钠浸出含砷铜矿脱砷工艺%Arsenic Removal from Arsenic-bearing Copper Ore by Sodium Hypochlorite Leaching Assisted with Microwave and Low-pressure Glow Discharge Plasma

    Institute of Scientific and Technical Information of China (English)

    赵卓英; 齐越; 杜冬云

    2015-01-01

    采用次氯酸钠浸出方法降低含砷铜矿中的砷含量.最佳工艺条件为:温度30℃、粒度54~74μm、NaClO浓度0.39 mol/L、NaOH用量为矿样的1.67%、时间90 min、液固比40:1(mL/g),砷浸出率为47.53%.微波场和辉光放电等离子体场辅助次氯酸钠浸出,砷浸出率分别为66%、72.88%,处理后铜矿中砷含量分别降至0.15%、0.12%,均满足铜精矿二级品砷含量的指标要求.

  20. Preparation of Copper-Cobalt-Silicon Catalysts for Higher Alcohol Synthesis by Glow Discharge Plasma%射频等离子体技术制备合成低碳醇用新型Cu-Co/SiO_2催化剂

    Institute of Scientific and Technical Information of China (English)

    徐慧远; 储伟; 邓思玉

    2010-01-01

    采用射频等离子体技术制备新型Cu-Co/SiO_2催化剂.与直接焙烧制备的样品相比,射频等离子体处理提高了催化剂的比表面积,显著增大了活性物种Co的表面含量,有效改进了催化剂的还原性能.以CO加氢合成低碳混合醇为模型反应,在563 K, 5.0 MPa,6000 h~(-1),V(H_2):V(CO)=1.6的条件下,等离子体处理和等离子体处理后再焙烧样品比673 K焙烧样品的催化活性提高30.46%和65.30%,低碳醇的时空收率分别提高58.22%和76.11%.

  1. 揭示生命奥秘的荧光——2008年度诺贝尔化学奖成果简介%The Life's Secret-revealing Fluorescent Glow-An Introduction to Achievements of the Nobel Prize in Chemistry for 2008

    Institute of Scientific and Technical Information of China (English)

    杭海英

    2008-01-01

    瑞典皇家科学院将2008年度诺贝尔化学奖授予美国日籍科学家下村修(Osamu Shimomura)、美国科学家马丁·查非(Martin Chalfie)和美籍华裔科学家钱永健(Roger Yonchien Tsien),以表彰他们在发现荧光蛋白质、改造和开发其在生物及相关领域研究的应用中做出的杰出成就.下村修首先在水晶水母(Aequorea victoria)的发光器官里发现了绿色荧光蛋白质(Green Fluorescence Protein,GFP);查非的研究揭示GFP可以在别的生物如细菌和线虫表达、发光,并可用于各种蛋白质在生物体内的示踪;钱永健则对GFP的结构和发光机理进行了深入研究,将GFP改造成各种颜色的荧光蛋白质和多种便于使用的型式.使它们在各类研究甚至非研究领域中获得广泛应用.三人专业背景和贡献方式各不相同.就像一场最终获得冠军的接力赛跑,三人都扮演了关键的角色.对于强调创新的今天都具有深刻启示作用.

  2. Quantitative trace element and depth profile analyses of refractory metals based materials using high resolution glow-discharge mass spectrometry%利用高分辨辉光放电质谱技术对难熔金属材料进行痕量元素定量和深度剖面分析

    Institute of Scientific and Technical Information of China (English)

    PUTYERA Karol; BOYEA Nick; CUQ Nicole; MICHELLON Cyril

    2010-01-01

    直接采样的高分辨辉光放电质谱(GDMS)是当今高纯固体常规分析中可用的高灵敏度分析方法之一.这种多元素分析技术通常用于主量化学成分的定量分析、监测元素质量分数随微米级深度(深度分布)的变化,或用于对多种固体和镀层上肉眼可见体积的高灵敏度的分布研究,包括纯金属、高温合金、陶瓷或其中陶瓷金属.由于GDMS的检测几乎涵盖了所有方法,因此在监测痕量级的多元素含量方面是最具成本优势的.另外,它使对在包含绝缘层和(或)镀层及两者化合物的平面上的高灵敏度的含量深度分布分析成为可能.本文着重介绍直流辉光质谱技术用于监测痕量至超含量元素分析技术目前的进展以及直接采样分析实践中应当采用的策略.

  3. 让习作评改焕发出生命的活力——小学作文"贴页式评改"方式的探索%Letting Composition Marking Glow the Vitality of Life-Exploration of the Mode of"Post Page Marking"of Composition in Primary School

    Institute of Scientific and Technical Information of China (English)

    赵万文

    2015-01-01

    有效的作文评改方式能保护学生的作文兴趣 ,也能提高学生修改作文的能力."贴页式评改"便是一种能够提高学生修改能力和写作能力的有效方式."贴页式评改"的基本流程包括"确定本次评改项目→制定评改表→上好评改课→合作评改→教师反馈→评比表彰".在实施的过程中要关注以下几个方面 :统一修改符号 ,强调规范性 ;组建四人小组 ,突出主体性 ;提出常规要求 ,增强针对性 ;善于引导 ,明确方向性 ;找出亮点 ,增强共享性 ;填好表格 ,注意激励性.通过贴页式评改 ,使小学生达到督促提醒、问题归类、习惯养成、反复推敲、互相学习、优势互补、合作竞争、写作兴趣浓厚而不再怕作文的目的.%The effective ways of marking composition can protect the students' interest in writing as well as improve their ability to modify the composition ."Post page marking"is an effective way to improve students' writing skills and ability to modify .The basic process of "Post page marking" includes:determining the marking items,making tables,delivering good lectures relating to composition marking,cooperation while marking,teachers' feedback and appraisal recognition .Attention should be paid to the following aspects In the process of implementation:unifying modified symbol and emphasizing normative;establishing four people team and highlighting the subjectivity ;putting forward the general requirements and strengthening the pertinence;guiding and making clear direction;finding out the bright spots and enhancing sharing ;filling out the tables and paying attention to the incentive .In doing so,the primary school students can supervise and urge to remind each other,classify questions,form good habits,think twice while marking,learn from each other,cooperate in competition,and in the end the students will have strong interests in writing and no longer be afraid of composition .

  4. VAMAS - Versailles project on Advanced Materials and Standards. Technical working area (TWA) 2: surface chemical analysis. Project A4: evaluation of multilayer reference, coatings for quantitative glow discharge, optical emission spectrometry (GD-OES), and other depth profiling techniques. Report on an inter-laboratory comparison

    Energy Technology Data Exchange (ETDEWEB)

    Beck, U.; Fritz, T.; Gamer, N.; Wirth, T.

    2001-06-01

    The main objective was the evaluation of two different reference coating systems, one conducting for the assessment of dc-GD-OES and one non-conducting for the evaluation of rf-GD-OES. Furthermore, the performance of various dc- and rf-systems was to be studied and the trueness of analysis had to be verified. A restriction was made to two different classes of layer materials: one conducting (on conducting substrate) and one non-conducting (on non-conducting substrate). Hence, with respect to conductivity two coating/substrate systems were provided: TiO{sub 2}/SiO{sub 2}-multilayer (on BK7 glass), and Ti/Al-multilayer (on 100Cr6 steel). (orig.)

  5. Observation of mode transition and low-frequency oscillations in magnetically constricted anode

    Science.gov (United States)

    Chauhan, S.; Ranjan, M.; Bandyopadhyay, M.; Mukherjee, S.

    2016-12-01

    We report on the discharge behaviour and the mode transition observed in a magnetically constricted anode device. With an increase in pressure, the central droplet shaped glow shrunk and abruptly switched to peripheral glow mode for pressure above 5 ×10-2 mbar . This transition is observed when the width of the droplet shaped glow at the anode approaches the diameter of the central magnet. The mode transition is observed as a sudden jump in the discharge current, which obeys a different power law than the previous discharge mode. Further, this new mode is observed to accompany the global oscillations in the range of few kHz.

  6. 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.

  7. Ion Nitriding of Titanium Alloys with a Hollow Cathode Effect Application

    Directory of Open Access Journals (Sweden)

    V.V. Budilov

    2015-09-01

    Full Text Available The method of ion nitriding the titanium VT6 alloy in glow discharge with the hollow cathode effect (HCE was investigated. Probe measurements of glow discharge plasma under HCE conditions and without it were performed; ion densities near the cathode surface were measured. The effect of HCE on microstructure, microhardness and wear resistance of VT6 alloy was determined. The technology of ion nitriding titanium alloys, based on phase modification of the surface layer in glow discharge with HCE, was developed.

  8. Gender bias found in recommendation letters

    Science.gov (United States)

    Kruesi, Liz

    2016-11-01

    Female postdoctoral fellowship applicants are half as likely as their male counterparts to receive glowing recommendation letters, according to a study by researchers at Columbia University's Lamont-Doherty Earth Observatory (LDEO).

  9. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... easily treated condition that occurs if you don't have enough iron in your body. Low iron ... can occur if your red blood cells don't contain enough hemoglobin (HEE-muh-glow-bin). Hemoglobin ...

  10. Ambipolar Diffusion in Direct-Current Positive Column with Variations in Radius of Discharge Tube

    Institute of Scientific and Technical Information of China (English)

    D. AKBAR; S. BILIKMEN

    2006-01-01

    @@ The ambipolar diffusion and argon ion mobility as functions of the reduced electric field and pressure times the tube radius are investigated in a weakly ionized non-uniform glow discharge plasma system.

  11. null Lamington, Papua New Guinea Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dormant stratovolcano in Papua New Guinea suddenly exploded in 1951. Nu?es ardentes (glowing avalanches) shot down the mountain at 100 km per hour, devastated...

  12. cosmic transformation

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Translucent nude tones and reflective greys are warmed up with glowing pinks and molten metallics, contrasted by deep, mysterious darks. The uses of fluorescents, particularly pink as a touch create the unexpected.

  13. Confined Disposal Facility at Pointe Mouillee for Detroit and Rouge Rivers.

    Science.gov (United States)

    1974-03-01

    34. Dunlin (Erolia alpina ) 35. Sanderling (Crocethia alba) 36. White-rumped Sandpiper (Erolia fuscicollis) 37. Knot (Calidris canutus) 38. Pectoral...thistle (Cirsium arvense) Golden Glow (Rudbeckia laciniata) Horsetail rush (Equisetum fluviatile) Skullcap ( Scutellaria sp) Water lily, white (Nymphaea

  14. Thermoluminescent kinetics parameters of inorganic dust from camomile

    Energy Technology Data Exchange (ETDEWEB)

    Furetta, C.; Cruz Z, E. [ICN-UNAM, A.P. 70-543, 04510 Mexico D.F. (Mexico); Favalli, A. [European Commission, Joint Research Centre, Institute for the Protection and Security of Citizen, TP800, Via E. Fermi 21020, Ispra VA (Italy); Gomez R, J.M. [CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Kitis, G. [Nuclear Physics Laboratory, University of Thessaloniky (Greece)

    2006-07-01

    The poly mineral dust extracted from camomile herb was exposed to gamma radiation. The glow curves from these poly minerals show a large, single TL peak, centred at about 440 K. Because the large structure of the glow curves, it seems that the TL signal could be produced by a trap distribution instead of a single level. The thermoluminescent kinetic parameters of the glow curves have been accurately analysed using the Computerized Glow Curve Deconvolution (CGCD) applied at different steps during fading experiment at room temperature (RT). Deconvolution has been performed using a continuous distribution of trapping levels, uniformly distributed, including one additional peak in the high temperature region. This peak has been modelled with second-order kinetics. (Author)

  15. Thermoluminescence investigations in X-ray irradiated CaS phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Adhikary, S. [Department of Applied Physics, Indian School of Mines University, Dhanbad 826004 (India); Choubey, A., E-mail: anjani_physics@yahoo.co [Department of Applied Physics, Indian School of Mines University, Dhanbad 826004 (India); Das, S.; Sharma, S.K.; Manam, J. [Department of Applied Physics, Indian School of Mines University, Dhanbad 826004 (India)

    2010-01-07

    We report the thermoluminescence studies of X-ray irradiated CaS phosphor. The CaS phosphor was prepared by solid-state diffusion method and characterized by X-ray diffraction technique (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Thermally stimulated luminescence (TSL) glow curves of X-ray irradiated CaS sample have two glow peaks at temperatures 100 and 130 {sup o}C. A reliable dosimetric study of a thermoluminescence material is based on good knowledge of its trapping parameters. The trapping parameters namely activation energy, order of kinetics and frequency factor associated with the prominent glow peak (130 {sup o}C) of CaS phosphor were calculated by using isothermal decay and glow curve shape (Chen's) methods.

  16. Standard Firebrand Generator

    Data.gov (United States)

    Federal Laboratory Consortium — This apparatus, developed at EL, has been constructed to generate a controlled and repeatable size and mass distribution of glowing firebrands. The purpose of NIST...

  17. Thermoluminescence of photostimulable materials after X irradiation below room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, S.; Iwasa, H.; Kurobori, T.; Inabe, K

    2002-07-01

    Thermoluminescence glow peaks in the temperature range 100 to 400 K are investigated for BaFX (X=Cl, Br) crystals after X irradiation at 100 K. A prominent glow peak of BaFCl around 210 K is found to be composed of a few recombination roots, that is, the peak corresponds to the recombination of hole trapped centers such as an O{sup -} center and a dissociated Cl{sub 2}{sup -} center with the F (F{sup -}) center and the O{sup 2-}-F(Cl{sup -}) pair defect. Another small glow peak around 270 K is likely to occur from thermal dissociation of the O{sup 2-}-F(Cl{sup -}) pair defect. Main glow peak of BaFBr:O{sup 2-} at 170 K may be attributed to a recombination of an O{sup -} center with the F(Br{sup -}) center. (author)

  18. Thermoluminescence of magnesium aluminum spinel

    CERN Document Server

    Kim, T K; Woo, J J; Chung, K S; Choe, H S; Jang, H K; Whang, C N

    1999-01-01

    The three dimensional TL spectrum of MgAl sub 2 O sub 4 exposed to UV light for 600 seconds produces one glow curve at 474 K which is due to the second-kinetics. The activation energy and the escape-frequency factor are calculated to be 0.85 eV and 1.92 x 10 sup 6 sec sup - sup 1 , respectively. The full widths at half maximum of the spectra of the 520-nm and the 710-nm emission bands associated with the holed captured at the V sup 2 sup + and the Cr sup 2 sup + sites, respectively, depend on temperature. The broad width of the glow curve is caused by an overlap of glow curves with different emission wavelengths and the difference in their peak temperatures. The peak of the glow curve shifts toward lower temperature as the UV-light exposure time increases.

  19. Helping Xinjiang Catch Up

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Guangdong explores new methods to aid Xinjiang While China’s eastern coastal regions bask in the glow of an economic boom following initiation of the reform and opening up policy in 1978,inland Xinjiang Uygur Autonomous Region lags behind.

  20. All organic host-guest crystals based on a dumb-bell-shaped conjugated host for light harvesting through resonant energy transfer.

    Science.gov (United States)

    Winkler, Reingard; Berger, Ricarda; Manca, Marianna; Hulliger, Jürg; Weber, Edwin; Loi, Maria A; Botta, Chiara

    2012-01-16

    Together we glow: Fully organic host-guest crystals with two dyes inserted in their parallel nanochannels display broad emission in the visible range thanks to resonant energy transfer. The conjugated host crystal provides light harvesting in the UV region.