WorldWideScience

Sample records for plasma thermal effects

  1. Thermal plasmas: fundamental aspects

    International Nuclear Information System (INIS)

    Fauchais, P.

    2005-01-01

    This article treats of thermal plasmas, i.e. mainly produced by electric arcs and RF discharges. Their main characteristic is that they are generated at a pressure close to the atmospheric pressure (between 10 4 and 10 6 Pa) and refer to the classical kinetics of the Boltzmann equation. Because of the pressure, the collisions between particles are numerous and ionization is mainly due to a thermal effect. They correspond to electron densities between 10 20 and 10 24 m -3 and temperatures between 6000 and 25000 K. In these plasmas, the electric fields and the average free trajectories are too weak to generate a ionization state by direct inelastic collision. Ionization is thus essentially a thermal phenomenon due to elastic collisions. This article presents: 1 - the particles present in a plasma: definition, energy states; 2 - characteristic data: collisions, average free path and collision cross-section, distribution function, ionization types, charged particles mobility inside an electric field, scattering, Debye length; 3 - plasmas at the thermodynamical equilibrium: conditions of equilibrium, calculation of composition, thermodynamic properties, transport properties, radiation; 4 - thermal plasmas away from equilibrium: conditions of non-equilibrium, calculation of plasma composition, calculation of transport properties, quenching phenomenon. (J.S.)

  2. Oblique propagation of electron thermal modes below the electron plasma frequency without boundary effects

    International Nuclear Information System (INIS)

    Ohnuma, T.; Watanabe, T.; Sanuki, H.

    1981-08-01

    Propagation characteristics and refractive effects of an oblique electron thermal mode without boundary effects below the electron plasma frequency are studied experimentally and theoretically in an inhomogeneous magnetized plasma. The behavior of this mode observed experimentally was confirmed by the theoretical analysis based on a new type of ray theory. (author)

  3. Comparative analysis of turbulent effects on thermal plasma characteristics inside the plasma torches with rod- and well-type cathodes

    International Nuclear Information System (INIS)

    Hur, Min; Hong, Sang Hee

    2002-01-01

    The thermal plasma characteristics inside the two non-transferred plasma torches with rod-type cathode (RTC) and well-type cathode (WTC) are analysed in conjunction with turbulent effects on them in the atmospheric-pressure conditions. A control volume method and a modified semi-implicit pressure linked equations revised algorithm are used for solving the governing equations, i.e. conservation equations of mass, momentum, and energy together with a current continuity equation for arc discharge. A cold flow analysis is introduced to find the cathode spot position in the WTC torch, and both the laminar and turbulent models are employed to gain a physical insight into the turbulent effects on the thermal plasma characteristics produced inside the two torches. The numerical analysis for an RTC torch shows that slightly different values of plasma temperature and velocity between the laminar and turbulent calculations occur and the radial temperature profiles are constricted at the axis with increasing the gas flow rate, and that the large turbulent viscosities appear mostly near the anode wall. These calculated results indicate that the turbulent effects on the thermal plasma characteristics are very weak in the whole discharge region inside the RTC torch. On the other hand, the calculated results of the two numerical simulations for a WTC torch present that the significantly different values of plasma characteristics between the two models appear in the whole torch region and the plasma temperatures decrease with increasing the gas flow rate because the relatively strong turbulent effects are prevailing in the entire interior region of the WTC torch. From the comparisons of plasma net powers calculated and measured in this work, the turbulent modelling turns out to provide the more accurately calculated results close to the measured ones compared with the laminar one, especially for the torch with WTC. This is because the turbulent effects are considerably strong in

  4. Revisiting the thermal effect on shock wave propagation in weakly ionized plasmas

    International Nuclear Information System (INIS)

    Zhou, Qianhong; Dong, Zhiwei; Yang, Wei

    2016-01-01

    Many researchers have investigated shock propagation in weakly ionized plasmas and observed the following anomalous effects: shock acceleration, shock recovery, shock weakening, shock spreading, and splitting. It was generally accepted that the thermal effect can explain most of the experimental results. However, little attention was paid to the shock recovery. In this paper, the shock wave propagation in weakly ionized plasmas is studied by fluid simulation. It is found that the shock acceleration, weakening, and splitting appear after it enters the plasma (thermal) region. The shock splits into two parts right after it leaves the thermal region. The distance between the splitted shocks keeps decreasing until they recover to one. This paper can explain a whole set of features of the shock wave propagation in weakly ionized plasmas. It is also found that both the shock curvature and the splitting present the same photoacoustic deflection (PAD) signals, so they cannot be distinguished by the PAD experiments.

  5. Investigation of non-thermal plasma effects on lung cancer cells within 3D collagen matrices

    Science.gov (United States)

    Karki, Surya B.; Thapa Gupta, Tripti; Yildirim-Ayan, Eda; Eisenmann, Kathryn M.; Ayan, Halim

    2017-08-01

    Recent breakthroughs in plasma medicine have identified a potential application for the non-thermal plasma in cancer therapy. Most studies on the effects of non-thermal plasma on cancer cells have used traditional two-dimensional (2D) monolayer cell culture. However, very few studies are conducted employing non-thermal plasma in animal models. Two dimensional models do not fully mimic the three-dimensional (3D) tumor microenvironment and animal models are expensive and time-consuming. Therefore, we used 3D collagen matrices that closely resemble the native geometry of cancer tissues and provide more physiologically relevant results than 2D models, while providing a more cost effective and efficient precursor to animal studies. We previously demonstrated a role for non-thermal plasma application in promoting apoptotic cell death and reducing the viability of A549 lung adenocarcinoma epithelial cells cultured upon 2D matrices. In this study, we wished to determine the efficacy of non-thermal plasma application in driving apoptotic cell death of A549 lung cancer cells encapsulated within a 3D collagen matrix. The percentage of apoptosis increased as treatment time increased and was time dependent. In addition, the anti-viability effect of plasma was demonstrated. Twenty-four hours post-plasma treatment, 38% and 99% of cell death occurred with shortest (15 s) and longest treatment time (120 s) respectively at the plasma-treated region. We found that plasma has a greater effect on the viability of A549 lung cancer cells on the superficial surface of 3D matrices and has diminishing effects as it penetrates the 3D matrix. We also identified the nitrogen and oxygen species generated by plasma and characterized their penetration in vertical and lateral directions within the 3D matrix from the center of the plasma-treated region. Therefore, the utility of non-thermal dielectric barrier discharge plasma in driving apoptosis and reducing the viability of lung cancer cells

  6. Investigation of non-thermal plasma effects on lung cancer cells within 3D collagen matrices

    International Nuclear Information System (INIS)

    Karki, Surya B; Gupta, Tripti Thapa; Yildirim-Ayan, Eda; Ayan, Halim; Eisenmann, Kathryn M

    2017-01-01

    Recent breakthroughs in plasma medicine have identified a potential application for the non-thermal plasma in cancer therapy. Most studies on the effects of non-thermal plasma on cancer cells have used traditional two-dimensional (2D) monolayer cell culture. However, very few studies are conducted employing non-thermal plasma in animal models. Two dimensional models do not fully mimic the three-dimensional (3D) tumor microenvironment and animal models are expensive and time-consuming. Therefore, we used 3D collagen matrices that closely resemble the native geometry of cancer tissues and provide more physiologically relevant results than 2D models, while providing a more cost effective and efficient precursor to animal studies. We previously demonstrated a role for non-thermal plasma application in promoting apoptotic cell death and reducing the viability of A549 lung adenocarcinoma epithelial cells cultured upon 2D matrices. In this study, we wished to determine the efficacy of non-thermal plasma application in driving apoptotic cell death of A549 lung cancer cells encapsulated within a 3D collagen matrix. The percentage of apoptosis increased as treatment time increased and was time dependent. In addition, the anti-viability effect of plasma was demonstrated. Twenty-four hours post-plasma treatment, 38% and 99% of cell death occurred with shortest (15 s) and longest treatment time (120 s) respectively at the plasma-treated region. We found that plasma has a greater effect on the viability of A549 lung cancer cells on the superficial surface of 3D matrices and has diminishing effects as it penetrates the 3D matrix. We also identified the nitrogen and oxygen species generated by plasma and characterized their penetration in vertical and lateral directions within the 3D matrix from the center of the plasma-treated region. Therefore, the utility of non-thermal dielectric barrier discharge plasma in driving apoptosis and reducing the viability of lung cancer cells

  7. Investigation of non thermal effects from the Dα line wings in edge plasmas

    International Nuclear Information System (INIS)

    Marandet, Y.; Godbert-Mouret, L.; Koubiti, M.; Stamm, R.; Capes, H.; Guirlet, R.

    2002-01-01

    The far wings of intense Dα lines measured at the edge of the Tore Supra Tokamak are found to exhibit a power-law behavior. The characteristic exponent is not far from two. Since the low density rules out thermal Stark broadening, we discuss non thermal effects which may arise from the edge plasma drift-wave turbulence. We suggest that both the Stark and the Doppler profile could be affected by the turbulence

  8. Modeling of thermal effects on TIBER II divertor during plasma disruptions

    International Nuclear Information System (INIS)

    Bruhn, M.L.; Perkins, L.J.

    1987-01-01

    Mapping the disruption power flow from the mid-plane of the TIBER Engineering Test Reactor to its divertor and calculating the resulting thermal effects are accomplished through the modification and coupling of three presently existing computer codes. The resulting computer code TADDPAK (Thermal Analysis Divertor during Disruption PAcKage) provides three-dimensional graphic presentations of time and positional dependent thermal effects on a poloidal cross section of the double-null-divertor configured reactor. These thermal effects include incident heat flux, surface temperature, vaporization rate, total vaporization, and melting depth. The dependence of these thermal effects on material choice, disruption pulse shape, and the characteristic thickness of the plasma scrape-off layer is determined through parametric analysis with TADDPAK. This computer code is designed to be a convenient, rapid, and user-friendly modeling tool which can be easily adapted to most tokamak double-null-divertor reactor designs

  9. Thermal plasma waste treatment

    International Nuclear Information System (INIS)

    Heberlein, Joachim; Murphy, Anthony B

    2008-01-01

    Plasma waste treatment has over the past decade become a more prominent technology because of the increasing problems with waste disposal and because of the realization of opportunities to generate valuable co-products. Plasma vitrification of hazardous slags has been a commercial technology for several years, and volume reduction of hazardous wastes using plasma processes is increasingly being used. Plasma gasification of wastes with low negative values has attracted interest as a source of energy and spawned process developments for treatment of even municipal solid wastes. Numerous technologies and approaches exist for plasma treatment of wastes. This review summarizes the approaches that have been developed, presents some of the basic physical principles, provides details of some specific processes and considers the advantages and disadvantages of thermal plasmas in waste treatment applications. (topical review)

  10. Effects of nitrogen seeding on core ion thermal transport in JET ILW L-mode plasmas

    NARCIS (Netherlands)

    Bonanomi, N.; Mantica, P.; Citrin, J.; Giroud, C.; Lerche, E.; Sozzi, C.; Taylor, D.; Tsalas, M.; Van Eester, D.; JET Contributors,

    2018-01-01

    A set of experiments was carried out in JET ILW (Joint European Torus with ITER-Like Wall) L-mode plasmas in order to study the effects of light impurities on core ion thermal transport. N was puffed into some discharges and its profile was measured by active Charge Exchange diagnostics, while ICRH

  11. Thermal effects in intense laser-plasma interactions

    International Nuclear Information System (INIS)

    Shadwick, B.A.; Tarkenton, G.M.; Esarey, E.H.

    2004-01-01

    We present an overview of a new warm fluid model that incorporates leading-order kinetic corrections to the cold fluid model without making any near-equilibrium assumptions. In the quasi-static limit we obtain analytical expressions for the momentum spread and show excellent agreement with solutions of the full time-dependant equations. It is shown that over a large range of initial plasma temperatures, the fields are relatively insensitive to the pressure force. We discuss implications of this work for model validation

  12. SUPERFAST THERMALIZATION OF PLASMA

    Science.gov (United States)

    Chang, C.C.

    1962-06-12

    A method is given for the superfast thermalization of plasma by shock conversion of the kinetic energy stored in rotating plasma rings or plasmoids colliding at near supersonic speeds in a containment field to heat energy in the resultant confined plasma mass. The method includes means for generating rotating plasmoids at the opposite ends of a Pyrotron or Astron containment field. The plasmoids are magnetically accelerated towards each other into the opposite ends of time containment field. During acceleration of the plasmoids toward the center of the containment field, the intensity of the field is sequentially increased to adiabatically compress the plasmoids and increase the plasma energy. The plasmoids hence collide with a violent shock at the eenter of the containment field, causing the substantial kinetic energy stored in the plasmoids to be converted to heat in the resultant plasma mass. (AEC)

  13. Non-thermal effects in a hot dense plasma

    International Nuclear Information System (INIS)

    Jones, L.A.; Kania, D.R.; Hammel, B.A.; Kallne, E.; Maestas, M.D.; McGurn, J.; Shepherd, R.

    1985-01-01

    A hollow gas shell Z-pinch device is described, and some initial observations are shown to lead to the conclusion that there is an energetic electron beam produced along the axis of the collapsing gas shell. An experiment is summarized that directly measured some of the characteristics of this runaway electron beam. Finally, the results of an experiment which observed a new affect are presented along with a model that uses a runaway electron beam to explain this new effect. 9 refs., 17 figs

  14. Study of the thermal effect on silicon surface induced by ion beam from plasma focus device

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Z., E-mail: pscientific5@aec.org.sy [Scientific Service Department, Atomic Energy Commission of Syria, P.O. Box: 6091, Damascus (Syrian Arab Republic); Ahmad, M. [IBA Laboratory, Atomic Energy Commission of Syria, P.O. Box: 6091, Damascus (Syrian Arab Republic); Chemistry Department, Atomic Energy Commission of Syria, P.O. Box: 6091, Damascus (Syrian Arab Republic); Al-Hawat, Sh.; Akel, M. [Physics Department, Atomic Energy Commission of Syria, P.O. Box: 6091, Damascus (Syrian Arab Republic)

    2017-04-01

    Structural modifications in form of ripples and cracks are induced by nitrogen ions from plasma focus on silicon surface. The investigation of such structures reveals correlation between ripples and cracks formation in peripheral region of the melt spot. The reason of such correlation and structure formation is explained as result of thermal effect. Melting and resolidification of the center of irradiated area occur within one micro second of time. This is supported by a numerical simulation used to investigate the thermal effect induced by the plasma focus ion beams on the silicon surface. This simulation provides information about the temperature profile as well as the dynamic of the thermal propagation in depth and lateral directions. In accordance with the experimental observations, that ripples are formed in latter stage after the arrival of last ion, the simulation shows that the thermal relaxation takes place in few microseconds after the end of the ion beam arrival. Additionally, the dependency of thermal propagation and relaxation on the distance of the silicon surface from the anode is presented.

  15. Parametric analysis of the thermal effects on the divertor in tokamaks during plasma disruptions

    International Nuclear Information System (INIS)

    Bruhn, M.L.

    1988-04-01

    Plasma disruptions are an ever present danger to the plasma-facing components in today's tokamak fusion reactors. This threat results from our lack of understanding and limited ability to control this complex phenomenon. In particular, severe energy deposition occurs on the divertor component of the double-null configured tokamak reactor during such disruptions. A hybrid computational model developed to estimate and graphically illustrate global thermal effects of disruptions on the divertor plates is described in detail. The quasi-two-dimensional computer code, TADDPAK (Thermal Analysis Divertor during Disruptions PAcKage), is used to conduct parametric analysis for the TIBER II Tokamak Engineering Test Reactor Design. The dependence of these thermal effects on divertor material choice, disruption pulse length, disruption pulse shape, and the characteristic thickness of the plasma scrape-off layer is investigated for this reactor design. Results and conclusions from this analysis are presented. Improvements to this model and issues that require further investigation are discussed. Cursory analysis for ITER (International Thermonuclear Experimental Reactor) is also presented in the appendix. 75 refs., 49 figs., 10 tabs

  16. Effects of thermal plasma on self-absorbed synchrotron sources in active galactic nuclei

    International Nuclear Information System (INIS)

    De Kool, M.; Begelman, M.C.

    1989-01-01

    The observable effects of a thermal background plasma in a self-absorbed synchrotron source are reviewed, in the context of a model for the central engine of an active galactic nucleus (AGN). Considering the effects of free-free absorption and emission, Thomson and Compton scattering, and spatial stratification, it is found that the observations set an upper limit on the thermal electron scattering optical depth in the central synchrotron-emitting region of an AGN. The upper limit, tau(max) about 1, results mainly from the apparent absence of induced Compton scattering and inverse thermal Comptonization effects. The low value of tau(max) poses some problems for nonthermal models of the AGN continuum that can be partly resolved by assuming a thin disk or layer-like geometry for the source, with (h/R) less than about 0.01. A likely site for the synchrotron-producing region seems to be the surface of an accretion disk or torus. 20 refs

  17. Monitoring system for thermal plasma

    International Nuclear Information System (INIS)

    Romero G, M.; Vilchis P, A.E.

    1999-01-01

    In the Thermal plasma applications laboratory it has been the degradation project of oils for isolation in transformers. These are a very hazardous residues and at this time in the country they are stored in metal barrels. It has been the intention to undergo the oils to plasma for degradate them to non-hazardous residues. The system behavior must be monitored to establish the thermal plasma behavior. (Author)

  18. An investigation of non-equilibrium effects in thermal argon plasmas

    International Nuclear Information System (INIS)

    Rosado, R.J.

    1981-01-01

    This thesis deals with the study of the validity of the assumption of Local Thermal Equilibrium (LTE) in the description of the parameters of a thermal argon plasma. The aim is twofold. As the studied plasma is close to, but not completely in equilibrium, the author first attempts to obtain a simple description of the plasma in terms of an LTE model in which suitable corrections for the deviations of the plasma parameters from their LTE values is introduced. To this end the plasma parameters are studied by means of a diagnostic method in which the assumption of LTE is not made. The evaluation of the usefulness of this method is the second aim of this thesis. (Auth.)

  19. Plasma effects on the passive external thermal control coating of Space Station Freedom

    Science.gov (United States)

    Carruth, Ralph, Jr.; Vaughn, Jason A.; Holt, James M.; Werp, Richard; Sudduth, Richard D.

    1992-01-01

    The current baseline chromic acid anodized thermal control coating on 6061-T6 aluminum meteoroid debris (M/D) shields for SSF has been evaluated. The degradation of the solar absorptance, alpha, and the thermal emittance, epsilon, of chromic acid anodized aluminum due to dielectric breakdown in plasma was measured to predict the on-orbit lifetime of the SSF M/D shields. The lifetime of the thermal control coating was based on the surface temperatures achieved with degradation of the thermal control properties, alpha and epsilon. The temperatures of each M/D shield from first element launch (FEL) through FEL+15 years were analyzed. It is shown that the baseline thermal control coating cannot withstand the -140 V potential between the conductive structure of the SSF and the current plasma environment.

  20. Effects of plasma jet parameters, ionization, thermal conduction, and radiation on stagnation conditions of an imploding plasma liner

    Science.gov (United States)

    Stanic, Milos

    The disciplines of High Energy Density Physics (HEDP) and Inertial Confinement Fusion (ICF) are characterized by hypervelocity implosions and strong shocks. The Plasma Liner Experiment (PLX) is focused on reaching HEDP and/or ICF relevant regimes in excess of 1 Mbar peak pressure by the merging and implosion of discrete plasma jets, as a potentially efficient path towards these extreme conditions in a laboratory. In this work we have presented the first 3D simulations of plasma liner, formation, and implosion by the merging of discrete plasma jets in which ionization, thermal conduction, and radiation are all included in the physics model. The study was conducted by utilizing a smoothed particle hydrodynamics code (SPHC) and was a part of the plasma liner experiment (PLX). The salient physics processes of liner formation and implosion are studied, namely vacuum propagation of plasma jets, merging of the jets (liner forming), implosion (liner collapsing), stagnation (peak pressure), and expansion (rarefaction wave disassembling the target). Radiative transport was found to significantly reduce the temperature of the liner during implosion, thus reducing the thermal expansion rates and leaving more pronounced gradients in the plasma liner during the implosion compared with ideal hydrodynamic simulations. These pronounced gradients lead to a greater sensitivity of initial jet geometry and symmetry on peak pressures obtained. Accounting for ionization and transport, many cases gave higher peak pressures than the ideal hydrodynamic simulations. Scaling laws were developed accordingly, creating a non-dimensional parameter space in which performance of an imploding plasma jet liner can be estimated. It is shown that HEDP regimes could be reached with ≈ 5 MJ of liner energy, which would translate to roughly 10 to 20 MJ of stored (capacitor) energy. This is a potentially significant improvement over the currently available means via ICF of achieving HEDP and nuclear

  1. Non-local thermodynamic equilibrium effects on isentropic coefficient in argon and helium thermal plasmas

    International Nuclear Information System (INIS)

    Sharma, Rohit; Singh, Kuldip

    2014-01-01

    In the present work, two cases of thermal plasma have been considered; the ground state plasma in which all the atoms and ions are assumed to be in the ground state and the excited state plasma in which atoms and ions are distributed over various possible excited states. The variation of Zγ, frozen isentropic coefficient and the isentropic coefficient with degree of ionization and non-equilibrium parameter θ(= T e /T h ) has been investigated for the ground and excited state helium and argon plasmas at pressures 1 atm, 10 atm, and 100 atm in the temperature range from 6000 K to 60 000 K. For a given value of non-equilibrium parameter, the relationship of Zγ with degree of ionization does not show any dependence on electronically excited states in helium plasma whereas in case of argon plasma this dependence is not appreciable till degree of ionization approaches 2. The minima of frozen isentropic coefficient shifts toward lower temperature with increase of non-equilibrium parameter for both the helium and argon plasmas. The lowering of non-equilibrium parameter decreases the frozen isentropic coefficient more emphatically in helium plasma at high pressures in comparison to argon plasma. The increase of pressure slightly reduces the ionization range over which isentropic coefficient almost remains constant and it does not affect appreciably the dependence of isentropic coefficient on non-equilibrium parameter

  2. Ions and electrons thermal effects on the fast-slow mode conversion process in a three components plasma

    International Nuclear Information System (INIS)

    Fidone, I.; Gomberoff, L.

    1977-07-01

    Fast-slow mode conversion in a deuterium plasma with a small amount of hydrogen impurity, for frequencies close to the two-ion hybrid frequency, is investigated. It is shown that while electron thermal effects tend to inhibit the wave conversion process, ion thermal effects tend to restore, qualitatively, the cold plasma properties, favouring therefore, the energy exchange between the two modes. The aforementioned effects are competitive for zetasub(o)sup(e)=1/nsub(parall).vsub(e)>=1. For zetasub(o)sup(e)<=1, electron thermal effects, in particular Landau damping, dominate over ion Larmor radius effects, drastically diminishing the wave conversion efficacy. For zetasub(o)sup(e)<<1, the coupling between the modes disappears altogether

  3. Effects of background fluid on the efficiency of inactivating yeast with non-thermal atmospheric pressure plasma.

    Directory of Open Access Journals (Sweden)

    Young-Hyo Ryu

    Full Text Available Non-thermal plasma at atmospheric pressure has been actively applied to sterilization. However, its efficiency for inactivating microorganisms often varies depending on microbial species and environments surrounding the microorganisms. We investigated the influence of environmental factors (surrounding media on the efficiency of microbial inactivation by plasma using an eukaryotic model microbe, Saccharomyces cerevisiae, to elucidate the mechanisms for differential efficiency of sterilization by plasma. Yeast cells treated with plasma in water showed the most severe damage in viability and cell morphology as well as damage to membrane lipids, and genomic DNA. Cells in saline were less damaged compared to those in water, and those in YPD (Yeast extract, Peptone, Dextrose were least impaired. HOG1 mitogen activated protein kinase was activated in cells exposed to plasma in water and saline. Inactivation of yeast cells in water and saline was due to the acidification of the solutions by plasma, but higher survival of yeast cells treated in saline may have resulted from the additional effect related to salt strength. Levels of hydroxyl radical (OH· produced by plasma were the highest in water and the lowest in YPD. This may have resulted in differential inactivation of yeast cells in water, saline, and YPD by plasma. Taken together, our data suggest that the surrounding media (environment can crucially affect the outcomes of yeast cell plasma treatment because plasma modulates vital properties of media, and the toxic nature of plasma can also be altered by the surrounding media.

  4. Modeling of thermal effects on TIBER II [Tokamak Ignition/Burn Experimental Reactor] divertor during plasma disruption

    International Nuclear Information System (INIS)

    Bruhn, M.L.; Perkins, L.J.

    1987-01-01

    Mapping the disruption power flow from the mid-plane of the TIBER Engineering Test Reactor to its divertor and calculating the resulting thermal effects are accomplished through the modification and coupling of three presently existing computer codes. The resulting computer code TADDPAK (Thermal Analysis Divertor during Disruption PAcKage) provides three-dimensional graphic presentations of time and positional dependent thermal effects on a poloidal cross section of the double-null-divertor configured reactor. These thermal effects include incident heat flux, surface temperature, vaporization rate, total vaporization, and melting depth. The dependence of these thermal effects on material choice, disruption pulse shape, and the characteristic thickness of the plasma scrape-off layer is determined through parametric analysis with TADDPAK. This computer code is designed to be a convenient, rapid, and user-friendly modeling tool which can be easily adapted to most tokamak double-null-divertor reactor designs. 14 refs

  5. Optoelectronic properties of expanding thermal plasma deposited textured zinc oxide : effect of aluminum doping

    NARCIS (Netherlands)

    Groenen, R.; Kieft, E.R.; Linden, J.L.; Sanden, van de M.C.M.

    2006-01-01

    Aluminum-doped zinc oxide films exhibiting a rough surface morphol. are deposited on glass substrates utilizing expanding thermal plasma. Spectroscopic ellipsometry is used to evaluate optical and electronic film properties. The presence of aluminum donors in doped films is confirmed by a shift in

  6. Analysis of the biological effects of a non-thermal plasma on saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Park, Gyung S.; Baik, Ku Y.; Kim, Jung G.; Kim, Yun J.; Lee, Kyung A.; Jung, Ran J.; Cho, Guang S.

    2012-01-01

    The cellular and the molecular responses of eukaryotic yeast (Saccharomyces cerevisiae) to a non-thermal plasma at atmospheric pressure are analyzed. A plasma device with a dielectric barrier discharge is used in order to understand the mechanisms of the plasma action on eukaryotic microbes. When the yeast cells are exposed to a plasma (at a 2-mm distance) and then cultured on a YPD (yeast extract, peptone, and dextrose) - agar plate, the number of surviving cells is reduced over exposure time. More than a 50% reduction in number is observed after two exposures of 5 minutes' duration. In addition, very small whitish colonies appear after the two exposures. The microscopic analysis indicates that the yeast cells treated with this plasma exposure have rough and shrunken shapes in comparison to the oval shapes with smooth surfaces of the control cells. The profile of proteins analyzed by using 2-dimentional electrophoresis demonstrates that the level of proteins with high molecular weights is increased in plasma-treated cells.

  7. Effects of non-thermal plasmas and electric field on hydrocarbon/air flames

    Science.gov (United States)

    Ganguly, Biswa

    2009-10-01

    Need to improve fuel efficiency, and reduce emission from hydrocarbon combustor in automotive and gas turbine engines have reinvigorated interest in reducing combustion instability of a lean flame. The heat generation rate in a binary reaction is HQ =N^2 c1c2 Q exp(-E/RT), where N is the density, c1 and c2 are mol fractions of the reactants, Q is the reaction heat release, E is the activation energy, R is the gas constant and T is the average temperature. For hydrocarbon-air reactions, the typical value of E/R ˜20, so most heat release reactions are confined to a thin reaction sheet at T >=1400 K. The lean flame burning condition is susceptible to combustion instability due to a critical balance between heat generation and heat loss rates, especially at high gas flow rate. Radical injection can increase flame speed by reducing the hydrocarbon oxidation reaction activation barrier and it can improve flame stability. Advances in nonequilibrium plasma generation at high pressure have prompted its application for energy efficient radical production to enhance hydrocarbon-air combustion. Dielectric barrier discharges and short pulse excited corona discharges have been used to enhance combustion stability. Direct electron impact dissociation of hydrocarbon and O2 produces radicals with lower fuel oxidation reaction activation barriers, initiating heat release reaction CnHm+O CnHm-1+ OH (and other similar sets of reactions with partially dissociated fuel) below the typical cross-over temperature. Also, N2 (A) produced in air discharge at a moderate E/n can dissociate O2 leading to oxidation of fuel at lower gas temperature. Low activation energy reactions are also possible by dissociation of hydrocarbon CnHm+e -> CnHm-2+H2+e, where a chain propagation reaction H2+ O OH+H can be initiated at lower gas temperature than possible under thermal equilibrium kinetics. Most of heat release comes from the reaction CO+OH-> CO2 +H, nonthermal OH production seem to improve

  8. Thermal Plasma decomposition of fluoriated greenhouse gases

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Soo Seok; Watanabe, Takayuki [Tokyo Institute of Technology, Yokohama (Japan); Park, Dong Wha [Inha University, Incheon (Korea, Republic of)

    2012-02-15

    Fluorinated compounds mainly used in the semiconductor industry are potent greenhouse gases. Recently, thermal plasma gas scrubbers have been gradually replacing conventional burn-wet type gas scrubbers which are based on the combustion of fossil fuels because high conversion efficiency and control of byproduct generation are achievable in chemically reactive high temperature thermal plasma. Chemical equilibrium composition at high temperature and numerical analysis on a complex thermal flow in the thermal plasma decomposition system are used to predict the process of thermal decomposition of fluorinated gas. In order to increase economic feasibility of the thermal plasma decomposition process, increase of thermal efficiency of the plasma torch and enhancement of gas mixing between the thermal plasma jet and waste gas are discussed. In addition, noble thermal plasma systems to be applied in the thermal plasma gas treatment are introduced in the present paper.

  9. Observation of non-chemical equilibrium effect on Ar-CO2-H2 thermal plasma model by changing pressure

    International Nuclear Information System (INIS)

    Al-Mamun, Sharif Abdullah; Tanaka, Yasunori; Uesugi, Yoshihiko

    2009-01-01

    The authors developed a two-dimensional one-temperature chemical non-equilibrium (1T-NCE) model of Ar-CO 2 -H 2 inductively coupled thermal plasmas (ICTP) to investigate the effect of pressure variation. The basic concept of one-temperature model is the assumption and treatment of the same energy conservation equation for electrons and heavy particles. The energy conservation equations consider reaction heat effects and energy transfer among the species produced as well as enthalpy flow resulting from diffusion. Assuming twenty two (22) different particles in this model and by solving mass conservation equations for each particle, considering diffusion, convection and net production terms resulting from hundred and ninety eight (198) chemical reactions, chemical non-equilibrium effects were taken into account. Transport and thermodynamic properties of Ar-CO 2 -H 2 thermal plasmas were self-consistently calculated using the first-order approximation of the Chapman-Enskog method. Finally results obtained at atmospheric pressure (760 Torr) and at reduced pressure (500, 300 Torr) were compared with results from one-temperature chemical equilibrium (1T-CE) model. And of course, this comparison supported discussion of chemical non-equilibrium effects in the inductively coupled thermal plasmas (ICTP).

  10. Non-thermal hydrogen plasma processing effectively increases the antibacterial activity of graphene oxide

    Science.gov (United States)

    Ke, Zhigang; Ma, Yulong; Zhu, Zhongjie; Zhao, Hongwei; Wang, Qi; Huang, Qing

    2018-01-01

    Graphene-based materials (GMs) are promising antibacterial agents which provide an alternative route to treat pathogenic bacteria with resistance to conventional antibiotics. To further improve their antibacterial activity, many methods have been developed to functionalize the GMs with chemicals. However, the application of additional chemicals may pose potential risks to the environment and human being. Herein, a radio-frequency-driven inductively coupled non-thermal hydrogen plasma was used to treat and reduce graphene oxide (GO) without using any other chemicals, and we found that the plasma-reduced GO (prGO) is with significantly higher bactericidal activity against Escherichia coli. The mechanism of the increased antibacterial activity of prGO is due to that plasma processing breaks down the GO sheets into smaller layers with more rough surface defects, which can thus induce more destructive membrane damages to the bacteria. This work sets another good example, showing that plasma processing is a green and low-cost alternative for GM modification for biomedical applications.

  11. The effect of electron thermal conduction on plasma pressure gradient during reconnection of magnetic field lines

    International Nuclear Information System (INIS)

    Chu, T.K.

    1987-12-01

    The interplay of electron cross-field thermal conduction and the reconnection of magnetic field lines around an m = 1 magnetic island prior to a sawtooth crash can generate a large pressure gradient in a boundary layer adjacent to the reconnecting surface, leading to an enhanced gradient of poloidal beta to satisfy the threshold condition for ideal MHD modes. This narrow boundary layer and the short onset time of a sawtooth crash can be supported by fine-grained turbulent processes in a tokamak plasma. 11 refs

  12. Thermal plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Heberlein, J.; Pfender, E.

    1993-01-01

    Thermal plasmas, with temperatures up to and even exceeding 10 4 K, are capable of producing high density vapor phase precursors for the deposition of relatively thick films. Although this technology is still in its infancy, it will fill the void between the relatively slow deposition processes such as physical vapor deposition and the high rate thermal spray deposition processes. In this chapter, the present state-of-the-art of this field is reviewed with emphasis on the various types of reactors proposed for this emerging technology. Only applications which attracted particular attention, namely diamond and high T c superconducting film deposition, are discussed in greater detail. (orig.)

  13. Observed and modelled effects of auroral precipitation on the thermal ionospheric plasma: comparing the MICA and Cascades2 sounding rocket events

    Science.gov (United States)

    Lynch, K. A.; Gayetsky, L.; Fernandes, P. A.; Zettergren, M. D.; Lessard, M.; Cohen, I. J.; Hampton, D. L.; Ahrns, J.; Hysell, D. L.; Powell, S.; Miceli, R. J.; Moen, J. I.; Bekkeng, T.

    2012-12-01

    Auroral precipitation can modify the ionospheric thermal plasma through a variety of processes. We examine and compare the events seen by two recent auroral sounding rockets carrying in situ thermal plasma instrumentation. The Cascades2 sounding rocket (March 2009, Poker Flat Research Range) traversed a pre-midnight poleward boundary intensification (PBI) event distinguished by a stationary Alfvenic curtain of field-aligned precipitation. The MICA sounding rocket (February 2012, Poker Flat Research Range) traveled through irregular precipitation following the passage of a strong westward-travelling surge. Previous modelling of the ionospheric effects of auroral precipitation used a one-dimensional model, TRANSCAR, which had a simplified treatment of electric fields and did not have the benefit of in situ thermal plasma data. This new study uses a new two-dimensional model which self-consistently calculates electric fields to explore both spatial and temporal effects, and compares to thermal plasma observations. A rigorous understanding of the ambient thermal plasma parameters and their effects on the local spacecraft sheath and charging, is required for quantitative interpretation of in situ thermal plasma observations. To complement this TRANSCAR analysis we therefore require a reliable means of interpreting in situ thermal plasma observation. This interpretation depends upon a rigorous plasma sheath model since the ambient ion energy is on the order of the spacecraft's sheath energy. A self-consistent PIC model is used to model the spacecraft sheath, and a test-particle approach then predicts the detector response for a given plasma environment. The model parameters are then modified until agreement is found with the in situ data. We find that for some situations, the thermal plasma parameters are strongly driven by the precipitation at the observation time. For other situations, the previous history of the precipitation at that position can have a stronger

  14. Synergistic effects of non-thermal plasma-assisted catalyst and ultrasound on toluene removal.

    Science.gov (United States)

    Sun, Yongli; Zhou, Libo; Zhang, Luhong; Sui, Hong

    2012-01-01

    A wire-mesh catalyst coated by La0.8Sr0.2MnO3 was combined with a dielectric barrier discharge (DBD) reactor for toluene removal at atmospheric pressure. It was found that toluene removal efficiency and carbon dioxide selectivity were enhanced in the catalytic packed-bed reactor. In addition, ozone and nitrogen monoxide from the gas effluent byproducts decreased. This is the first time that ultrasound combined with plasma has been used for toluene removal. A synergistic effect on toluene removal was observed in the plasma-assisted ultrasound system. At the same time, the system increased toluene conversion and reduced ozone emission.

  15. Thermal stability of the tokamak plasma edge

    International Nuclear Information System (INIS)

    Stacey, W.M.

    1997-01-01

    The general linear, fluid, thermal instability theory for the plasma edge has been extended. An analysis of a two-dimensional fluid model of the plasma edge has identified the importance of many previously unappreciated phenomena associated with parallel and gyroviscous forces in the presence of large radial gradients, with large radial or parallel flows, with the temperature dependence of transport coefficients, and with the coupling of temperature, flow and density perturbations. The radiative condensation effect is generalized to include a further destabilizing condensation effect associated with radial heat conduction. Representative plasma edge neutral and impurity densities are found to be capable of driving thermal instabilities in the edge transport barrier and radiative mantle, respectively. (author)

  16. Effect of non-thermal air atmospheric pressure plasma jet treatment on gingival wound healing

    International Nuclear Information System (INIS)

    Lee, Jung-Hwan; Choi, Eun-Ha; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2016-01-01

    Non-thermal atmospheric pressure plasmas have been applied in the biomedical field for the improvement of various cellular activities. In dentistry, the healing of gingival soft tissue plays an important role in health and aesthetic outcomes. While the biomedical application of plasma has been thoroughly studied in dentistry, a detailed investigation of plasma-mediated human gingival fibroblast (HGF) migration for wound healing and its underlying biological mechanism is still pending. Therefore, the aim of this study is to apply a non-thermal air atmospheric pressure plasma jet (NTAAPPJ) to HGF to measure the migration and to reveal the underlying biological mechanisms involved in the migration. After the characterization of NTAAPPJ by optical emission spectroscopy, the adherent HGF was treated with NTAAPPJ or air with a different flow rate. Cell viability, lipid peroxidation, migration, intracellular reactive oxygen species (ROS), and the expression of migration-related genes (EGFR, PAK1, and MAPK3) were investigated. The level of statistical significance was set at 0.05. NTAAPPJ and air treatment with a flow rate of 250–1000 standard cubic centimetres per minute (sccm) for up to 30 s did not induce significant decreases in cell viability or membrane damage. A significant increase in the migration of mitomycin C-treated HGF was observed after 30 s of NTAAPPJ treatment compared to 30 s air-only treatment, which was induced by high levels of intracellular reactive oxygen species (ROS). An increase in migration-related gene expression and EGFR activation was observed following NTAAPPJ treatment in an air flow rate-dependent manner. This is the first report that NTAAPPJ treatment induces an increase in HGF migration without changing cell viability or causing membrane damage. HGF migration was related to an increase in intracellular ROS, changes in the expression of three of the migration-related genes (EGFR, PAK1, and MAPK1), and EGFR activation. Therefore

  17. Effect of Non Thermal Plasma on Alfalfa (Medicago sativa L.) Forage Production

    International Nuclear Information System (INIS)

    Abd El-Daem, G.A.N.A.; El-Aragi, G.M.; Tarrad, M.M.; Zayed, E.M.

    2013-01-01

    Field experiments were conducted at Atomic Energy Authority (AEA) Farm, at Inshas, Egypt during 2011–2012 on alfalfa. The aim of this investigation to caused mutation in alfalfa to obtain new variation. Seeds of the alfalfa were subjected to six doses of non-thermal plasma pulse. The plasma (consisting of ozone, UV and visible light) was injected into the seed samples for different durations or number of pulses. The doses used treatments were 2, 4, 6, 8, and 10 pulses (P) and non-treated control. The results showed difference seeds in both level field performances from cut 1st to cut 10th in the forage production. The results showed differences between the Control and treatment (number of pulses (P)) in each of all cuts for the productivity. The results showed the impact of plant height, Number of leaves/plant and number of branches/leaf and stem diameter as well as fresh weight of plant, fresh/weight (t/fed), dry yield (t/fed) in some cuts for Pulses 2, 4 and 10, and the ten pulses were the best for the majority of the qualities and cuts.

  18. Novel Therapeutic Effects of Non-thermal atmospheric pressure plasma for Muscle Regeneration and Differentiation

    Science.gov (United States)

    Choi, Jae Won; Kang, Sung Un; Kim, Yang Eun; Park, Ju Kyeong; Yang, Sang Sik; Kim, Yeon Soo; Lee, Yun Sang; Lee, Yuijina; Kim, Chul-Ho

    2016-01-01

    Skeletal muscle can repair muscle tissue damage, but significant loss of muscle tissue or its long-lasting chronic degeneration makes injured skeletal muscle tissue difficult to restore. It has been demonstrated that non-thermal atmospheric pressure plasma (NTP) can be used in many biological areas including regenerative medicine. Therefore, we determined whether NTP, as a non-contact biological external stimulator that generates biological catalyzers, can induce regeneration of injured muscle without biomaterials. Treatment with NTP in the defected muscle of a Sprague Dawley (SD) rat increased the number of proliferating muscle cells 7 days after plasma treatment (dapt) and rapidly induced formation of muscle tissue and muscle cell differentiation at 14 dapt. In addition, in vitro experiments also showed that NTP could induce muscle cell proliferation and differentiation of human muscle cells. Taken together, our results demonstrated that NTP promotes restoration of muscle defects through control of cell proliferation and differentiation without biological or structural supporters, suggesting that NTP has the potential for use in muscle tissue engineering and regenerative therapies. PMID:27349181

  19. Inactivation of Candida biofilms by non-thermal plasma and its enhancement for fungistatic effect of antifungal drugs.

    Directory of Open Access Journals (Sweden)

    Yi Sun

    Full Text Available We investigated the antifungal effect of non-thermal plasma, as well as its combination with common antifungal drugs, against Candida biofilms. A direct current atmospheric pressure He/O(2 (2% plasma microjet (PMJ was used to treat Candida biofilms in a 96-well plate. Inactivation efficacies of the biofilms were evaluated by XTT assay and counting colony forming units (CFUs. Morphological properties of the biofilms were evaluated by Scanning Electron Microscope (SEM. The sessile minimal inhibitory concentrations (SMICs of fluconazole, amphotericin B, and caspofungin for the biofilms were also tested. Electron Spin Resonance (ESR spectroscopy was used to detect the reactive oxygen species (ROS generated directly and indirectly by PMJ. The Candida biofilms were completely inactivated after 1 min PMJ treatment, where severely deformed fungal elements were observed in SEM images. The SMICs of the tested antifungal drugs for the plasma-treated biofilms were decreased by 2-6 folds of dilution, compared to those of the untreated controls. ROS such as hydroxyl radical ((•OH, superoxide anion radical ((•O(2 (- and singlet molecular oxygen ((1O(2 were detected by ESR. We hence conclude that He/O(2 (2% plasma alone, as well as in combination with common antifungal drugs, is able to inactivate Candida biofilms rapidly. The generation of ROS is believed to be one of the underlying mechanisms for the fungicidal activity of plasma.

  20. Foundations of High-Pressure Thermal Plasmas

    Science.gov (United States)

    Murphy, Anthony B.; Uhrlandt, Dirk

    2018-06-01

    An introduction to the main methods used to produce, model and measure thermal plasmas is provided, with emphasis on the differences between thermal plasmas and other types of processing plasmas. The critical properties of thermal plasmas are explained in physical terms and their importance in different applications is considered. The characteristics, and advantages and disadvantages, of the different main types of thermal plasmas (transferred and non-transferred arcs, radio-frequency inductively-coupled plasmas and microwave plasmas) are discussed. The methods by which flow is stabilized in arc plasmas are considered. The important concept of local thermodynamic equilibrium (LTE) is explained, leading into a discussion of the importance of thermophysical properties, and their calculation in LTE and two-temperature plasmas. The standard equations for modelling thermal plasmas are presented and contrasted with those used for non-equilibrium plasmas. Treatments of mixed-gas and non-LTE plasmas are considered, as well as the sheath regions adjacent to electrodes. Finally, the main methods used for electrical, optical, spectroscopic and laser diagnostics of thermal plasmas are briefly introduced, with an emphasis on the required assumptions for their reliable implementation, and the specific requirements of thermal plasmas.

  1. Effects of fusion relevant transient energetic radiation, plasma and thermal load on PLANSEE double forged tungsten samples in a low-energy plasma focus device

    Science.gov (United States)

    Javadi, S.; Ouyang, B.; Zhang, Z.; Ghoranneviss, M.; Salar Elahi, A.; Rawat, R. S.

    2018-06-01

    Tungsten is the leading candidate for plasma facing component (PFC) material for thermonuclear fusion reactors and various efforts are ongoing to evaluate its performance or response to intense fusion relevant radiation, plasma and thermal loads. This paper investigates the effects of hot dense decaying pinch plasma, highly energetic deuterium ions and fusion neutrons generated in a low-energy (3.0 kJ) plasma focus device on the structure, morphology and hardness of the PLANSEE double forged tungsten (W) samples surfaces. The tungsten samples were provided by Forschungszentrum Juelich (FZJ), Germany via International Atomic Energy Agency, Vienna, Austria. Tungsten samples were irradiated using different number of plasma focus (PF) shots (1, 5 and 10) at a fixed axial distance of 5 cm from the anode top and also at various distances from the top of the anode (5, 7, 9 and 11 cm) using fixed number (5) of plasma focus shots. The virgin tungsten sample had bcc structure (α-W phase). After PF irradiation, the XRD analysis showed (i) the presence of low intensity new diffraction peak corresponding to β-W phase at (211) crystalline plane indicating the partial structural phase transition in some of the samples, (ii) partial amorphization, and (iii) vacancy defects formation and compressive stress in irradiated tungsten samples. Field emission scanning electron microscopy showed the distinctive changes to non-uniform surface with nanometer sized particles and particle agglomerates along with large surface cracks at higher number of irradiation shots. X-ray photoelectron spectroscopy analysis demonstrated the reduction in relative tungsten oxide content and the increase in metallic tungsten after irradiation. Hardness of irradiated samples initially increased for one shot exposure due to reduction in tungsten oxide phase, but then decreased with increasing number of shots due to increasing concentration of defects. It is demonstrated that the plasma focus device provides

  2. The effect of topical anesthetic hydration on the depth of thermal injury from the plasma skin regeneration device.

    Science.gov (United States)

    Sanderson, Alicia R; Wu, Edward C; Liaw, Lih-Huei L; Garg, Rohit; Gangnes, Richard A

    2014-02-01

    The plasma skin regeneration (PSR) device delivers thermal energy to the skin by converting nitrogen gas to plasma. Prior to treatment, hydration of the skin is recommended as it is thought to limit the zone of thermal damage. However, there is limited data on optimal hydration time. This pilot study aims to determine the effect of topical anesthetic application time on the depth of thermal injury from a PSR device using histology. PSR (1.8 and 3.5 J) was performed after 0, 30, or 60 minutes of topical anesthetic application. Rhytidectomy was then performed and skin was fixed for histologic analysis. Four patients (two control and four treatment sites per patient) undergoing rhytidectomy were recruited for the study. Each patient served as his/her own control (no hydration). A scoring system for tissue injury was developed. Epidermal injury, the presence of vacuolization, blistering, damage to adnexal structures, and depth of dermal collagen changes were evaluated in over 1,400 high-power microscopy fields. There was a significant difference in the average thermal injury score, depth of thermal damage, and epidermal injury when comparing controls to 30 minutes of hydration (P = 0.012, 0.012, 0.017, respectively). There was no statistical difference between controls and 60 minutes of hydration or between 30 and 60 minutes of hydration. Epidermal vacuolization at low energy and patchy distribution of thermal injury was also observed. Topical hydration influences the amount of thermal damage when applied to skin for 30 minutes prior to treatment with the PSR device. There was a trend toward decreasing thermal damage at 60 minutes, and there was no difference between treatment for 30 or 60 minutes. The data suggest that application of topical anesthetic for a short period of time prior to treatment with the PSR device is cost-effective, safe, and may be clinically beneficial. © 2013 Wiley Periodicals, Inc.

  3. Extremely high-power-density atmospheric-pressure thermal plasma jet generated by the nitrogen-boosted effect

    Science.gov (United States)

    Hanafusa, Hiroaki; Nakashima, Ryosuke; Nakano, Wataru; Higashi, Seiichiro

    2018-06-01

    In this study, the effect of N2 addition to an atmospheric-pressure Ar thermal plasma jet (TPJ) on ultrarapid heating was investigated. With increasing N2 flow rate, a boost of arc voltage to ∼36 V was observed, which significantly improved heating characteristics. As a result, a drastic power density increase from 10 to 125 kW/cm2 was achieved with the addition of 2.0 L/min N2 to 3.0 L/min Ar. The results of optical emission analysis and heating characteristics evaluation implied that dissociation and recombination of N2 molecules and the high thermal transport property of nitrogen gas play important roles in the increase in TPJ power density. Furthermore, we obtained TPJ extension with N2 addition that reached 300 mm, and it showed spatial enhancement of heat transport characteristics.

  4. Effects of gap and elevated pressure on ethanol reforming in a non-thermal plasma reactor

    International Nuclear Information System (INIS)

    Hoang, Trung Q; Zhu Xinli; Lobban, Lance L; Mallinson, Richard G

    2011-01-01

    Production of hydrogen for fuel cell vehicles, mobile power generators and for hydrogen-enhanced combustion from ethanol is demonstrated using energy-efficient non-thermal plasma reforming. A tubular reactor with a multipoint electrode system operated in pulsed mode was used. Complete conversion can be achieved with high selectivity (based on ethanol) of H 2 and CO of 111% and 78%, respectively, at atmospheric pressure. An elevated pressure of 15 psig shows improvement of selectivity of H 2 and CO to 120% and 87%, with a significant reduction of C 2 H x side products. H 2 selectivity increased to 127% when a high ratio (29.2) of water-to-ethanol feed was used. Increasing CO 2 selectivity is observed at higher water-to-ethanol ratios indicating that the water gas shift reaction occurs. A higher productivity and lower C 2 H x products were observed at larger gas gaps. The highest overall energy efficiency achieved, including electrical power consumption, was 82% for all products or 66% for H 2 only.

  5. Disinfection effect of non-thermal atmospheric pressure plasma for foodborne bacteria

    Science.gov (United States)

    Pervez, Mohammad Rasel; Inomata, Takanori; Ishijima, Tatsuo; Kakikawa, Makiko; Uesugi, Yoshihiko; Tanaka, Yasunori; Yano, Toshihiro; Miwa, Shoji; Noguchi, Akinori

    2015-09-01

    Non-thermal atmospheric pressure plasma (NAPP) exposure can be a suitable alternative for bacteria inactivation in food processing industry. Specimen placed in the enclosure are exposed to various reactive radicals produced within the discharge chamber. It is also exposed to the periodic variation of the electric field strength in the chamber. Dielectric barrier discharge is produced by high voltage pulse (Vpp = 18 kV, pulse width 20 μs, repetition frequency 10 kHz) in a polypropylene box (volume = 350 cm3) using helium as main feed gas. Inactivation efficiency of NAPP depends on the duration of NAPP exposure, applied voltage pulse strength and type, pulse duration, electrode separation and feed gas composition. In this study we have investigated inactivation of Bacillus lichenformis spore as an example of food borne bacteria. Keeping applied voltage, electrode configuration and total gas flow rate constant, spores are exposed to direct NAPP for different time duration while O2 concentration in the feed gas composition is varied. 10 minutes NAPP exposure resulted in ~ 3 log reduction of Bacillus lichenformis spores for 1% O2concentration (initial concentration ~ 106 / specimen). This work is supported by research and development promotion grant provided by the Hokuriku Industrial Advancement Center.

  6. Effect of indirect non-thermal plasma on particle size distribution and composition of diesel engine particles

    Science.gov (United States)

    Linbo, GU; Yixi, CAI; Yunxi, SHI; Jing, WANG; Xiaoyu, PU; Jing, TIAN; Runlin, FAN

    2017-11-01

    To explore the effect of the gas source flow rate on the actual diesel exhaust particulate matter (PM), a test bench for diesel engine exhaust purification was constructed, using indirect non-thermal plasma technology. The effects of different gas source flow rates on the quantity concentration, composition, and apparent activation energy of PM were investigated, using an engine exhaust particle sizer and a thermo-gravimetric analyzer. The results show that when the gas source flow rate was large, not only the maximum peak quantity concentrations of particles had a large drop, but also the peak quantity concentrations shifted to smaller particle sizes from 100 nm to 80 nm. When the gas source flow rate was 10 L min-1, the total quantity concentration greatly decreased where the removal rate of particles was 79.2%, and the variation of the different mode particle proportion was obvious. Non-thermal plasma (NTP) improved the oxidation ability of volatile matter as well as that of solid carbon. However, the NTP gas source rate had little effects on oxidation activity of volatile matter, while it strongly influenced the oxidation activity of solid carbon. Considering the quantity concentration and oxidation activity of particles, a gas source flow rate of 10 L min-1 was more appropriate for the purification of particles.

  7. Effects of nuclear forces on ion thermalization in high-temperature plasmas

    International Nuclear Information System (INIS)

    Gould, R.J.

    1982-01-01

    The energy loss rate is computed for a fast nonrelativistic ion traversing a plasma, with special emphasis on the basic problem of proton-proton ( p-p) interactions. Elastic p-p scattering is described in terms of the effective range r 0 and scattering length a 0 associated with the nuclear interaction. The nuclear s-wave phase shift (delta 0 ) in the presence of the Coulomb field is computed as a function of energy E 0 from the r 0 -a 0 formalism; delta 0 has a very weak energy dependence, essentially logarithmic, in the 1-100 MeV domain

  8. Effect of Microstructure on the Thermal Conductivity of Plasma Sprayed Y2O3 Stabilized Zirconia (8% YSZ

    Directory of Open Access Journals (Sweden)

    Ningning Hu

    2017-11-01

    Full Text Available In this paper, the effect of microstructure on the thermal conductivity of plasma-sprayed Y2O3 stabilized ZrO2 (YSZ thermal barrier coatings (TBCs is investigated. Nine freestanding samples deposited on aluminum alloys are studied. Cross-section morphology such as pores, cracks, m-phase content, grain boundary density of the coated samples are examined by scanning electron microscopy (SEM and electron back-scattered diffraction (EBSD. Multiple linear regressions are used to develop quantitative models that describe the relationship between the particle parameters, m-phase content and features of the microstructure such as porosity, crack-porosity, and the length density of small and big angle-cracks. Moreover, the relationship between the microstructure and thermal conductivity is investigated. Results reveal that the thermal conductivity of the coating is mainly determined by the microstructure and grain boundary density at room temperature (25 °C, and by the length density of big-angle-crack, monoclinic phase content and grain boundary density at high temperature (1200 °C.

  9. Diagnostic methods of thermal dusty plasma flows

    International Nuclear Information System (INIS)

    Nefedov, A.P.

    1995-01-01

    The presence in the high-temperature flows of condensed disperse phase (CDP) particles may lead either to an increase of the electron number density n e if the particles assume a positive charge or to its decrease if the charge is negative. The existence of CDP also may effect on optical parameters of the thermal dusty plasma flows, on heat and radiative transfer in the plasma. The entire range of states, from a Debye plasma to a highly nonideal system of charged particles, is realized in a thermal dusty plasma under standard conditions T=2000-3000 K, n e =10 8 - 10 14 cm -3 . The advanced probe and optical diagnostic instruments are needed to study the optical and electrophysical properties of thermal dusty plasma flows. The diagnostic techniques must give the data about such parameters of gas and dispersed phase as temperatures of gas and particles, number densities of electrons, atoms and ions of alkali metals, sizes, velocities and concentrations of CDP particles. It should be noted that number density of alkali metal atoms and gas temperature may be measured by the well known full absorption and generalized reversal methods. This paper describes the probe and optical techniques for diagnostic of dusty plasma flows developed in High Energy Density Research Center of Russian Academy of Sciences. The Forward Angle Scattering Transmissometer (FAST) allows measurement of the average size (Sauter diameter), mass number density, and refractive index of particles in the 0.5-15.0 gm size range. The basis of the method is a dependence of the measured extinction of radiation upon an angular acceptance aperture of the photo detector. The FAST instrument allows one to determine the mass density and the Sauter diameter of a polydispersion of particles without a priori specification of the particle size distribution model and exact data about the article refractive index

  10. Diagnostic methods of thermal dusty plasma flows

    International Nuclear Information System (INIS)

    Nefedov, A.P.

    1995-01-01

    The presence in the high-temperature flows of condensed disperse phase (CDP) particles may lead either to an increase of the electron number density n e if the particles assume a positive charge or to its decrease if the charge is negative. The existence of CDP also may effect on optical parameters of the thermal dusty plasma flows, on heat and radiative transfer in the plasma. The entire range of states, from a Debye plasma to a highly nonideal system of charged particles, is realized in a thermal dusty plasma under standard conditions T=2000-3000 K, n e =10 8 -10 14 cm -3 . The advanced probe and optical diagnostic instruments are needed to study the optical and electrophysical properties of thermal dusty plasma flows. The diagnostic techniques must give the data about such parameters of gas and dispersed phase as temperatures of gas and particles, number densities of electrons, atoms and ions of alkali metals, sizes, velocities and concentrations of CDP particles. It should be noted that number density of alkali metal atoms and gas temperature may be measured by the well known full absorption and generalized reversal methods. This paper describes the probe and optical techniques for diagnostic of dusty plasma flows developed in High Energy Density Research Center of Russian Academy of Sciences. The Forward Angle Scattering Transmissometer (FAST) allows measurement of the average size (Sauter diameter), mass number density, and refractive index of particles in the 0.5-15.0 μm size range. The basis of the method is a dependence of the measured extinction of radiation upon an angular acceptance aperture of the photo detector. The FAST instrument allows one to determine the mass density and the Sauter diameter of a polydispersion of particles without a priori specification of the particle size distribution model and exact data about the particle refractive index

  11. Implosive Thermal Plasma Source for Energy Conversion

    Czech Academy of Sciences Publication Activity Database

    Šonský, Jiří; Tesař, Václav; Gruber, Jan; Mašláni, Alan

    2017-01-01

    Roč. 4, č. 1 (2017), s. 87-90 ISSN 2336-2626 Institutional support: RVO:61388998 ; RVO:61389021 Keywords : implosion * thermal plasma * detonation wave Subject RIV: BL - Plasma and Gas Discharge Physics; BL - Plasma and Gas Discharge Physics (UFP-V) OBOR OECD: Fluids and plasma physics (including surface physics); Fluids and plasma physics (including surface physics) (UFP-V) https://ppt.fel.cvut.cz/ppt2017.html#number1

  12. Thermal Plasma Generators with Water Stabilized Arc

    Czech Academy of Sciences Publication Activity Database

    Hrabovský, Milan

    2009-01-01

    Roč. 2, č. 1 (2009), s. 99-104 ISSN 1876-5343 R&D Projects: GA ČR GA202/08/1084 Institutional research plan: CEZ:AV0Z20430508 Keywords : Thermal plasma * plasma torch * Gerdien arc Subject RIV: BL - Plasma and Gas Discharge Physics http://www.bentham.org/open/toppj/openaccess2.htm

  13. Technological challenges in thermal plasma production

    International Nuclear Information System (INIS)

    Ramakrishnan, S.

    1995-01-01

    Thermal plasmas, generated by electric arc discharges, are used in a variety of industrial applications. The electric arc is a constricted electrical discharge with a high temperature in the range 6000-25,000 K. These characteristics are useful in plasma cutting, spraying, welding and specific areas of material processing. The thermal plasma technology is an enabling process technology and its status in the market depends upon its advantages over competing technologies. A few technological challenges to enhance the status of plasma technology are to improve the utilisation of the unique characteristics of the electric arc and to provide enhanced control of the process. In particular, new solutions are required for increasing the plasma-material interaction, controlling the electrode roots and controlling the thermal power generated by the arcing process. In this paper, the advantages of plasma technology, its constraints and future challenges for technology developments are highlighted. 36 refs., 14 figs

  14. Plasma sheath criterion in thermal electronegative plasmas

    International Nuclear Information System (INIS)

    Ghomi, Hamid; Khoramabadi, Mansour; Ghorannevis, Mahmod; Shukla, Padma Kant

    2010-01-01

    The sheath formation criterion in electronegative plasma is examined. By using a multifluid model, it is shown that in a collisional sheath there will be upper as well as lower limits for the sheath velocity criterion. However, the parameters of the negative ions only affect the lower limit.

  15. Deviations from thermal equilibrium in plasmas

    International Nuclear Information System (INIS)

    Burm, K.T.A.L.

    2004-01-01

    A plasma system in local thermal equilibrium can usually be described with only two parameters. To describe deviations from equilibrium two extra parameters are needed. However, it will be shown that deviations from temperature equilibrium and deviations from Saha equilibrium depend on one another. As a result, non-equilibrium plasmas can be described with three parameters. This reduction in parameter space will ease the plasma describing effort enormously

  16. Synthesis of functional nanocrystallites through reactive thermal plasma processing

    Directory of Open Access Journals (Sweden)

    Takamasa Ishigaki and Ji-Guang Li

    2007-01-01

    Full Text Available A method of synthesizing functional nanostructured powders through reactive thermal plasma processing has been developed. The synthesis of nanosized titanium oxide powders was performed by the oxidation of solid and liquid precursors. Quench gases, either injected from the shoulder of the reactor or injected counter to the plasma plume from the bottom of the reactor, were used to vary the quench rate, and therefore the particle size, of the resultant powders. The experimental results are well supported by numerical analysis on the effects of the quench gas on the flow pattern and temperature field of the thermal plasma as well as on the trajectory and temperature history of the particles. The plasma-synthesized TiO2 nanoparticles showed phase preferences different from those synthesized by conventional wet-chemical processes. Nanosized particles of high crystallinity and nonequilibrium chemical composition were formed in one step via reactive thermal plasma processing.

  17. Effects caused by thermal shocks in plasma sprayed protective coatings from materials based on Al2O3

    International Nuclear Information System (INIS)

    Gorski, L.; Wolski, T.; Gostynski, D.

    1996-01-01

    Plasma sprayed coatings from the materials based on Al 2 O 3 with addition of NiO and TiO 2 have been studied. Thermal shock resistance of these coatings has been tested on special experimental arrangement in the stream of hot and cold gases. Changes in coating microstructure has been determined by light microscopy methods. Phase transition caused by the experiments are revealed by X-ray diffraction methods. The resistance for thermal fatigue processes depends on used coatings materials. (author). 21 refs, 21 figs, 1 tab

  18. Electrical and thermal conductivities in dense plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Faussurier, G., E-mail: gerald.faussurier@cea.fr; Blancard, C.; Combis, P.; Videau, L. [CEA, DAM, DIF, F-91297 Arpajon (France)

    2014-09-15

    Expressions for the electrical and thermal conductivities in dense plasmas are derived combining the Chester-Thellung-Kubo-Greenwood approach and the Kramers approximation. The infrared divergence is removed assuming a Drude-like behaviour. An analytical expression is obtained for the Lorenz number that interpolates between the cold solid-state and the hot plasma phases. An expression for the electrical resistivity is proposed using the Ziman-Evans formula, from which the thermal conductivity can be deduced using the analytical expression for the Lorenz number. The present method can be used to estimate electrical and thermal conductivities of mixtures. Comparisons with experiment and quantum molecular dynamics simulations are done.

  19. Dynamic plasma screening effects on atomic collisions in dense plasmas

    International Nuclear Information System (INIS)

    Young-Dae Jung

    1999-01-01

    Dynamic plasma screening effects are investigated on electron-ion collisional excitation and Coulomb Bremsstrahlung processes in dense plasmas. The electron-ion interaction potential is considered by introduction of the plasma dielectric function. The straight-ling trajectory method is applied to the path of the projectile electron. The transition probability including the dynamic plasma screening effect is found to be always greater than that including the static plasma screening effects. It is found that the differential Bremsstrahlung radiation cross section including the dynamic plasma screening effect is also greater than that including the static plasma screening effect. When the projectile velocity is smaller than the electron thermal velocity, the dynamic polarization screening effect becomes the static plasma screening effect. However, when the projectile velocity is greater than the electron thermal velocity, the interaction potential is almost unshielded

  20. The effects of thermal motion of neutrals on the non-potential instabilities in a weakly sodium plasma

    International Nuclear Information System (INIS)

    Zigman, V.J.; Milic, B.S.

    1982-01-01

    The results of recent experimental measurements of the differential cross-section for elastic scattering of electrons on sodium atoms are used to evaluate the electron steady-state distribution function in a weakly ionized, uniform and non-magnetized sodium plasma placed in a d.c. electric field. The field is assumed to be of moderate intensity, so that the thermal motion of the neutrals has to be taken into account in the evaluation of the distribution function. The resulting 'modified Druyvesteinian function' is applied to study the non-potential instabilities arising from the presence of the field in this particular plasma. Threshold drifts for both very slow and slow modes are obtained and the conditions for the onset of instabilities are discussed. It is shown that the thermal motion of the neutrals affects both critical drifts and the angles of propagation. (author)

  1. Energy deposition and thermal effects of runaway electrons in ITER-FEAT plasma facing components

    International Nuclear Information System (INIS)

    Maddaluno, G.; Maruccia, G.; Merola, M.; Rollet, S.

    2003-01-01

    The profile of energy deposited by runaway electrons (RAEs) of 10 or 50 MeV in International Thermonuclear Experimental Reactor-Fusion Energy Advanced Tokamak (ITER-FEAT) plasma facing components (PFCs) and the subsequent temperature pattern have been calculated by using the Monte Carlo code FLUKA and the finite element heat conduction code ANSYS. The RAE energy deposition density was assumed to be 50 MJ/m 2 and both 10 and 100 ms deposition times were considered. Five different configurations of PFCs were investigated: primary first wall armoured with Be, with and without protecting CFC poloidal limiters, both port limiter first wall options (Be flat tile and CFC monoblock), divertor baffle first wall, armoured with W. The analysis has outlined that for all the configurations but one (port limiter with Be flat tile) the heat sink and the cooling tube beneath the armour are well protected for both RAE energies and for both energy deposition times. On the other hand large melting (W, Be) or sublimation (C) of the surface layer occurs, eventually affecting the PFCs lifetime

  2. Energy deposition and thermal effects of runaway electrons in ITER-FEAT plasma facing components

    Science.gov (United States)

    Maddaluno, G.; Maruccia, G.; Merola, M.; Rollet, S.

    2003-03-01

    The profile of energy deposited by runaway electrons (RAEs) of 10 or 50 MeV in International Thermonuclear Experimental Reactor-Fusion Energy Advanced Tokamak (ITER-FEAT) plasma facing components (PFCs) and the subsequent temperature pattern have been calculated by using the Monte Carlo code FLUKA and the finite element heat conduction code ANSYS. The RAE energy deposition density was assumed to be 50 MJ/m 2 and both 10 and 100 ms deposition times were considered. Five different configurations of PFCs were investigated: primary first wall armoured with Be, with and without protecting CFC poloidal limiters, both port limiter first wall options (Be flat tile and CFC monoblock), divertor baffle first wall, armoured with W. The analysis has outlined that for all the configurations but one (port limiter with Be flat tile) the heat sink and the cooling tube beneath the armour are well protected for both RAE energies and for both energy deposition times. On the other hand large melting (W, Be) or sublimation (C) of the surface layer occurs, eventually affecting the PFCs lifetime.

  3. EFFECT OF FINITE LARMOR RADIUS CORRECTIONS ON THE THERMAL INSTABILITY OF THERMALLY CONDUCTING VISCOUS PLASMA WITH HALL CURRENT AND ELECTRON INERTIA

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Shweta; Sharma, Prerana [Physics Department, Ujjain Engineering College, Ujjain, MP-456010 (India); Kaothekar, Sachin [Physics Department, Mahakal Institute of Technology, Ujjain, MP-456664 (India); Chhajlani, R. K., E-mail: sackaothekar@gmail.com [Retired, School of Studies in Physics, Vikram University Ujjain, MP-456010 (India)

    2016-10-01

    The thermal instability of an infinite homogeneous, thermally conducting, and rotating plasma, incorporating finite electrical resistivity, finite electron inertia, and an arbitrary radiative heat-loss function in the presence of finite Larmor radius corrections and Hall current, has been studied. Analysis has been made with the help of linearized magnetohydrodynamics (MHD) equations. A general dispersion relation is obtained using the normal mode analysis method, and the dispersion relation is discussed for longitudinal propagation and transverse propagation separately. The dispersion relation has been solved numerically to obtain the dependence of the growth rate on the various parameters involved. The conditions of modified thermal instability and stability are discussed in the different cases of interest.

  4. Non-thermal plasma mills bacteria: Scanning electron microscopy observations

    International Nuclear Information System (INIS)

    Lunov, O.; Churpita, O.; Zablotskii, V.; Jäger, A.; Dejneka, A.; Deyneka, I. G.; Meshkovskii, I. K.; Syková, E.; Kubinová, Š.

    2015-01-01

    Non-thermal plasmas hold great promise for a variety of biomedical applications. To ensure safe clinical application of plasma, a rigorous analysis of plasma-induced effects on cell functions is required. Yet mechanisms of bacteria deactivation by non-thermal plasma remain largely unknown. We therefore analyzed the influence of low-temperature atmospheric plasma on Gram-positive and Gram-negative bacteria. Using scanning electron microscopy, we demonstrate that both Gram-positive and Gram-negative bacteria strains in a minute were completely destroyed by helium plasma. In contrast, mesenchymal stem cells (MSCs) were not affected by the same treatment. Furthermore, histopathological analysis of hematoxylin and eosin–stained rat skin sections from plasma–treated animals did not reveal any abnormalities in comparison to control ones. We discuss possible physical mechanisms leading to the shred of bacteria under non-thermal plasma irradiation. Our findings disclose how helium plasma destroys bacteria and demonstrates the safe use of plasma treatment for MSCs and skin cells, highlighting the favorability of plasma applications for chronic wound therapy

  5. Plasma Treatment of Agave Fiber Powder and Its Effect on the Mechanical and Thermal Properties of Composites Based on Polyethylene

    Directory of Open Access Journals (Sweden)

    Florentino Soriano Corral

    2016-01-01

    Full Text Available Composites based on low-density polyethylene (LDPE were prepared with Agave fiber powder (AFP that was coated by plasma polymerization process using ethylene gas. Treated and pristine AFP were analyzed by infrared spectroscopy, scanning electron microscopy, and contact water angle for the assessment of surface properties. The polymer composites were prepared by melt mixing using 0, 5, 10, and 20 wt% of AFP and their mechanical and thermal properties were measured. Dispersion evaluation in water confirmed that the AFP treated changed from hydrophilic to hydrophobic behavior and it was also corroborated with water contact angle tests. The addition of treated and untreated AFP (200 mesh at 20 wt% promotes an increase of Young’s modulus of the composites of up to 60% and 32%, respectively, in relation to the neat matrix. Also, an increase of crystallinity of LDPE was observed by the addition of treated and untreated AFP; however no significant effect on the crystallization temperature was observed in LDPE containing AFP.

  6. Thermal instability in a stratified plasma

    International Nuclear Information System (INIS)

    Hermanns, D.F.M.; Priest, E.R.

    1989-01-01

    The thermal instability mechansism has been studied in connection to observed coronal features, like, e.g. prominences or cool cores in loops. Although these features show a lot of structure, most studies concern the thermal instability in an uniform medium. In this paper, we investigate the thermal instability and the interaction between thermal modes and the slow magneto-acoustic subspectrum for a stratified plasma slab. We fomulate the relevant system of equations and give some straightforward properties of the linear spectrum of a non-uniform plasma slab, i.e. the existence of continuous parts in the spectrum. We present a numerical scheme with which we can investigate the linear spectrum for equilibrium states with stratification. The slow and thermal subspectra of a crude coronal model are given as a preliminary result. (author). 6 refs.; 1 fig

  7. Analytical method for thermal stress analysis of plasma facing materials

    Science.gov (United States)

    You, J. H.; Bolt, H.

    2001-10-01

    The thermo-mechanical response of plasma facing materials (PFMs) to heat loads from the fusion plasma is one of the crucial issues in fusion technology. In this work, a fully analytical description of the thermal stress distribution in armour tiles of plasma facing components is presented which is expected to occur under typical high heat flux (HHF) loads. The method of stress superposition is applied considering the temperature gradient and thermal expansion mismatch. Several combinations of PFMs and heat sink metals are analysed and compared. In the framework of the present theoretical model, plastic flow and the effect of residual stress can be quantitatively assessed. Possible failure features are discussed.

  8. Analytical method for thermal stress analysis of plasma facing materials

    International Nuclear Information System (INIS)

    You, J.H.; Bolt, H.

    2001-01-01

    The thermo-mechanical response of plasma facing materials (PFMs) to heat loads from the fusion plasma is one of the crucial issues in fusion technology. In this work, a fully analytical description of the thermal stress distribution in armour tiles of plasma facing components is presented which is expected to occur under typical high heat flux (HHF) loads. The method of stress superposition is applied considering the temperature gradient and thermal expansion mismatch. Several combinations of PFMs and heat sink metals are analysed and compared. In the framework of the present theoretical model, plastic flow and the effect of residual stress can be quantitatively assessed. Possible failure features are discussed

  9. Cytocompatibility of Plasma and Thermally Treated Biopolymers

    Directory of Open Access Journals (Sweden)

    Petr Slepička

    2013-01-01

    Full Text Available This paper is focused on the surface characterization of plasma and consequently thermally treated biocompatible polymers. PLLA (poly(L-lactide acid and PMP (poly-4-methyl-1-pentene are studied. The influence of Ar plasma treatment on the surface polarity of substrate measured immediately after treatment and during the polymer surface aging is studied. Surface roughness, morphology, wettability, and surface chemistry were determined. Plasma treatment leads to significant changes in PLLA surface morphology and chemistry, with the PMP being slightly affected. The higher resistance to plasma fluence results in smaller ablation of PMP than that of PLLA. The plasma treatment improves cell adhesion and proliferation on the PMP. Plasma treatment of PLLA influences mostly the homogeneity of adhered and proliferated VSMC.

  10. Thermally stimulated scattering in plasmas

    DEFF Research Database (Denmark)

    Dysthe, K. B.; Mjølhus, E.; Pécseli, H. L.

    1985-01-01

    this experiment local heat conduction is of little importance and the dynamic evolution for the electron temperature is dominated by heating and energy exchange with the ion component. These features are incorporated in the analysis. The resulting set of equations gives a growth rate and characteristic scale size......A theory for stimulated scattering of a laser beam is formulated where the dominant nonlinearity is the ohmic heating of the plasma. The analysis is carried out with particular reference to experimental investigations of CO2 laser heating of linear discharge plasma. In the conditions characterizing...

  11. Modeling of thermal plasma arc technology FY 1994 report

    International Nuclear Information System (INIS)

    Hawkes, G.L.; Nguyen, H.D.; Paik, S.; McKellar, M.G.

    1995-03-01

    The thermal plasma arc process is under consideration to thermally treat hazardous and radioactive waste. A computer model for the thermal plasma arc technology was designed as a tool to aid in the development and use of the plasma arc-Joule beating process. The value of this computer model is to: (a) aid in understanding the plasma arc-Joule beating process as applied to buried waste or exhumed buried waste, (b) help design melter geometry and electrode configuration, (c) calculate the process capability of vitrifying waste (i.e., tons/hour), (d) develop efficient plasma and melter operating conditions to optimize the process and/or reduce safety hazards, (e) calculate chemical reactions during treatment of waste to track chemical composition of off-gas products, and composition of final vitrified waste form and (f) help compare the designs of different plasma-arc facilities. A steady-state model of a two-dimensional axisymmetric transferred plasma arc has been developed and validated. A parametric analysis was performed that studied the effects of arc length, plasma gas composition, and input power on the temperatures and velocity profiles of the slag and plasma gas. A two-dimensional transient thermo-fluid model of the US Bureau of Mines plasma arc melter has been developed. This model includes the growth of a slag pool. The thermo-fluid model is used to predict the temperature and pressure fields within a plasma arc furnace. An analysis was performed to determine the effects of a molten metal pool on the temperature, velocity, and voltage fields within the slag. A robust and accurate model for the chemical equilibrium calculations has been selected to determine chemical composition of final waste form and off-gas based on the temperatures and pressures within the plasma-arc furnace. A chemical database has been selected. The database is based on the materials to be processed in the plasma arc furnaces

  12. Hydrogen production by thermal water splitting using a thermal plasma

    International Nuclear Information System (INIS)

    Boudesocque, N.; Lafon, C.; Girold, C.; Vandensteendam, C.; Baronnet, J.M.

    2006-01-01

    CEA has been working for more than 10 years in plasma technologies devoted to waste treatment: incineration, vitrification, gases and liquid treatment. Based on this experience, CEA experiments since several years an innovative route for hydrogen production by thermal water splitting, using a plasma as heat source. This new approach could be considered as an alternative to electrolysis for massive hydrogen production from water and electricity. This paper presents a brief state of the art of water thermal plasmas, showing the temperatures and quench velocity ranges technologically achievable today. Thermodynamic properties of a water plasma are presented and discussed. A kinetic computational model is presented, describing the behavior of splitted products during the quench in a plasma plume for various parameters, such as the quench rate. The model results are compared to gas analysis in the plasma plume obtained with in-situ sampling probe. The plasma composition measurements are issued from an Optical Emission Spectroscopic method (OES). The prediction of 30 % H 2 recovery with a 108 K.s -1 quench rate has been verified. A second experimentation has been performed: mass gas analysis, flowrate measurement and OES to study the 'behavior' and species in underwater electrical arc stricken between graphite electrodes. With this quench, a synthesis gas was produced with a content 55 % of hydrogen. (authors)

  13. Effect of Suspension Plasma-Sprayed YSZ Columnar Microstructure and Bond Coat Surface Preparation on Thermal Barrier Coating Properties

    Science.gov (United States)

    Bernard, Benjamin; Quet, Aurélie; Bianchi, Luc; Schick, Vincent; Joulia, Aurélien; Malié, André; Rémy, Benjamin

    2017-08-01

    Suspension plasma spraying (SPS) is identified as promising for the enhancement of thermal barrier coating (TBC) systems used in gas turbines. Particularly, the emerging columnar microstructure enabled by the SPS process is likely to bring about an interesting TBC lifetime. At the same time, the SPS process opens the way to a decrease in thermal conductivity, one of the main issues for the next generation of gas turbines, compared to the state-of-the-art deposition technique, so-called electron beam physical vapor deposition (EB-PVD). In this paper, yttria-stabilized zirconia (YSZ) coatings presenting columnar structures, performed using both SPS and EB-PVD processes, were studied. Depending on the columnar microstructure readily adaptable in the SPS process, low thermal conductivities can be obtained. At 1100 °C, a decrease from 1.3 W m-1 K-1 for EB-PVD YSZ coatings to about 0.7 W m-1 K-1 for SPS coatings was shown. The higher content of porosity in the case of SPS coatings increases the thermal resistance through the thickness and decreases thermal conductivity. The lifetime of SPS YSZ coatings was studied by isothermal cyclic tests, showing equivalent or even higher performances compared to EB-PVD ones. Tests were performed using classical bond coats used for EB-PVD TBC coatings. Thermal cyclic fatigue performance of the best SPS coating reached 1000 cycles to failure on AM1 substrates with a β-(Ni,Pt)Al bond coat. Tests were also performed on AM1 substrates with a Pt-diffused γ-Ni/γ'-Ni3Al bond coat for which more than 2000 cycles to failure were observed for columnar SPS YSZ coatings. The high thermal compliance offered by both the columnar structure and the porosity allowed the reaching of a high lifetime, promising for a TBC application.

  14. Transport of super-thermal particles and their effect on the stability of global modes in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Schneller, Mirjam Simone

    2013-08-02

    In thermonuclear plasmas, a population of super-thermal particles generated by external heating methods or fusion reactions can lead to the excitation of global instabilities. The transport processes due to nonlinear wave-particle interactions and the consequential particle losses reduce the plasma heating and the efficiency of the fusion reaction rate. Furthermore, these energetic or fast particles may cause severe damages to the wall of the device. This thesis addresses the resonance mechanisms between these energetic particles and global MHD and kinetic MHD waves, employing the hybrid code HAGIS. A systematic investigation of energetic particles resonant with multiple modes (double-resonance) is presented for the first time. The double-resonant mode coupling is modeled for waves with different frequencies in various overlapping scenarios. It is found that, depending on the radial mode distance, double-resonance is able to significantly enhance, both the growth rates and the saturation amplitudes. Small radial mode distances, however can lead to strong nonlinear mode stabilization of a linear dominant mode. For the first time, simulations of experimental conditions in the ASDEX Upgrade fusion device are performed for different plasma equilibria (particularly for different q profiles). An understanding of fast particle behavior for non-monotonic q profiles is important for the development of advanced fusion scenarios. The numerical tool is the extended version of the HAGIS code, which computes the particle motion in the vacuum region between vessel wall in addition to the internal plasma volume. For this thesis, a consistent fast particle distribution function was implemented, to represent the fast particle population generated by the particular heating method (ICRH). Furthermore, HAGIS was extended to use more realistic eigenfunctions, calculated by the gyrokinetic eigenvalue solver LIGKA. One important aim of these simulations is to allow fast ion loss

  15. Transport of super-thermal particles and their effect on the stability of global modes in fusion plasmas

    International Nuclear Information System (INIS)

    Schneller, Mirjam Simone

    2013-01-01

    In thermonuclear plasmas, a population of super-thermal particles generated by external heating methods or fusion reactions can lead to the excitation of global instabilities. The transport processes due to nonlinear wave-particle interactions and the consequential particle losses reduce the plasma heating and the efficiency of the fusion reaction rate. Furthermore, these energetic or fast particles may cause severe damages to the wall of the device. This thesis addresses the resonance mechanisms between these energetic particles and global MHD and kinetic MHD waves, employing the hybrid code HAGIS. A systematic investigation of energetic particles resonant with multiple modes (double-resonance) is presented for the first time. The double-resonant mode coupling is modeled for waves with different frequencies in various overlapping scenarios. It is found that, depending on the radial mode distance, double-resonance is able to significantly enhance, both the growth rates and the saturation amplitudes. Small radial mode distances, however can lead to strong nonlinear mode stabilization of a linear dominant mode. For the first time, simulations of experimental conditions in the ASDEX Upgrade fusion device are performed for different plasma equilibria (particularly for different q profiles). An understanding of fast particle behavior for non-monotonic q profiles is important for the development of advanced fusion scenarios. The numerical tool is the extended version of the HAGIS code, which computes the particle motion in the vacuum region between vessel wall in addition to the internal plasma volume. For this thesis, a consistent fast particle distribution function was implemented, to represent the fast particle population generated by the particular heating method (ICRH). Furthermore, HAGIS was extended to use more realistic eigenfunctions, calculated by the gyrokinetic eigenvalue solver LIGKA. One important aim of these simulations is to allow fast ion loss

  16. Non-thermal Plasma and Oxidative Stress

    Science.gov (United States)

    Toyokuni, Shinya

    2015-09-01

    Thermal plasmas and lasers have been used in medicine to cut and ablate tissues and for coagulation. Non-equilibrium atmospheric pressure plasma (NEAPP; non-thermal plasma) is a recently developed, non-thermal technique with possible biomedical applications. Although NEAPP reportedly generates reactive oxygen/nitrogen species, electrons, positive ions, and ultraviolet radiation, few research projects have been conducted to merge this technique with conventional free radical biology. Recently, Prof. Masaru Hori's group (Plasma Nanotechnology Research Center, Nagoya University) developed a NEAPP device with high electron density. Here electron spin resonance revealed hydroxyl radicals as a major product. To merge non-thermal plasma biology with the preexisting free radical biology, we evaluated lipid peroxidation and DNA modifications in various in vitro and ex vivo experiments. Conjugated dienes increased after exposure to linoleic and alfa-linolenic acids. An increase in 2-thiobarbituric acid-reactive substances was also increased after exposure to phosphatidylcholine, liposomes or liver homogenate. Direct exposure to rat liver in medium produced immunohistochemical evidence of 4-hydroxy-2-nonenal- and acrolein-modified proteins. Exposure to plasmid DNA induced dose-dependent single/double strand breaks and increased the amounts of 8-hydroxy-2'-deoxyguanosine and cyclobutane pyrimidine dimers. These results indicate that oxidative biomolecular damage by NEAPP is dose-dependent and thus can be controlled in a site-specific manner. Simultaneous oxidative and UV-specific DNA damage may be useful in cancer treatment. Other recent advancements in the related studies of non-thermal plasma in Nagoya University Graduate School of Medicine will also be discussed.

  17. Chemical durability of slag produced by thermal plasma melting of low-level miscellaneous solid wastes. Effects of slag composition

    International Nuclear Information System (INIS)

    Amakawa, Tadashi; Yasui, Shinji

    2001-01-01

    Low-level radioactive miscellaneous solid wastes are generated from commercial operation of nuclear power plants and will be generated from decommissioning of nuclear power plants in future. Static leaching tests were carried out in deionized water of 10degC on slag obtained by thermal plasma melting of simulating materials of the miscellaneous solids wastes with surrogate elements of radionuclides. It is found that logarithm of normalized elemental mass loss from the slag is proportional to the basicity represented by mole fractions of main structural oxides of the slag, such as SiO 2 , Al 2 O 3 , CaO, FeO and MgO. The range of static leaching rates from the slag is determined based on the above results and the basicity range of the miscellaneous solid wastes. Then we compared the leaching rates form the slag and from high level waste glasses. On these grounds, we concluded that the slag obtained by thermal plasma melting of miscellaneous solid wastes can stabilize radio-nuclides in it by no means inferior to the high level waste glasses. (author)

  18. Effects of a non thermal plasma treatment alone or in combination with gemcitabine in a MIA PaCa2-luc orthotopic pancreatic carcinoma model.

    Directory of Open Access Journals (Sweden)

    Laura Brullé

    Full Text Available Pancreatic tumors are the gastrointestinal cancer with the worst prognosis in humans and with a survival rate of 5% at 5 years. Nowadays, no chemotherapy has demonstrated efficacy in terms of survival for this cancer. Previous study focused on the development of a new therapy by non thermal plasma showed significant effects on tumor growth for colorectal carcinoma and glioblastoma. To allow targeted treatment, a fibered plasma (Plasma Gun was developed and its evaluation was performed on an orthotopic mouse model of human pancreatic carcinoma using a MIA PaCa2-luc bioluminescent cell line. The aim of this study was to characterize this pancreatic carcinoma model and to determine the effects of Plasma Gun alone or in combination with gemcitabine. During a 36 days period, quantitative BLI could be used to follow the tumor progression and we demonstrated that plasma gun induced an inhibition of MIA PaCa2-luc cells proliferation in vitro and in vivo and that this effect could be improved by association with gemcitabine possibly thanks to its radiosensitizing properties.

  19. Effects of a non thermal plasma treatment alone or in combination with gemcitabine in a MIA PaCa2-luc orthotopic pancreatic carcinoma model.

    Science.gov (United States)

    Brullé, Laura; Vandamme, Marc; Riès, Delphine; Martel, Eric; Robert, Eric; Lerondel, Stéphanie; Trichet, Valérie; Richard, Serge; Pouvesle, Jean-Michel; Le Pape, Alain

    2012-01-01

    Pancreatic tumors are the gastrointestinal cancer with the worst prognosis in humans and with a survival rate of 5% at 5 years. Nowadays, no chemotherapy has demonstrated efficacy in terms of survival for this cancer. Previous study focused on the development of a new therapy by non thermal plasma showed significant effects on tumor growth for colorectal carcinoma and glioblastoma. To allow targeted treatment, a fibered plasma (Plasma Gun) was developed and its evaluation was performed on an orthotopic mouse model of human pancreatic carcinoma using a MIA PaCa2-luc bioluminescent cell line. The aim of this study was to characterize this pancreatic carcinoma model and to determine the effects of Plasma Gun alone or in combination with gemcitabine. During a 36 days period, quantitative BLI could be used to follow the tumor progression and we demonstrated that plasma gun induced an inhibition of MIA PaCa2-luc cells proliferation in vitro and in vivo and that this effect could be improved by association with gemcitabine possibly thanks to its radiosensitizing properties.

  20. Thermal efficiency of a non-transferred thermal plasma cannon

    International Nuclear Information System (INIS)

    Mercado, A.; Cota, G.; Merlo, L.; Pacheco, J.; Pena, R.; Cruz, A.

    1997-01-01

    This work shows a thermal efficiency research (ν) for a plasma torch in d.c. which was carried out through the realization of an energy balance around the system under consideration. The plasma torch is manufactured in copper with a tungsten incrustations in cathode. The gas used was argon and the gas fluxes were at the rank of 10 and 40 lt/min to the total pressure of 1.2 bar (1.1 atm). With these conditions it was worked with electric currents at the rank of 40 and 180 A. The data were collected through a data acquisition card which was programmed in Windows environment. (Author)

  1. Effects of hydrogenation on thermal conductivity of ultrananocrystalline diamond/amorphous carbon composite films prepared via coaxial arc plasma deposition

    Science.gov (United States)

    Takeichi, Satoshi; Nishiyama, Takashi; Tabara, Mitsuru; Kawawaki, Shuichi; Kohno, Masamichi; Takahashi, Koji; Yoshitake, Tsuyoshi

    2018-06-01

    Ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) composite (UNCD/a-C:H) and UNCD/non-hydrogenated amorphous carbon (a-C) composite (UNCD/a-C) films were prepared via coaxial arc plasma deposition, and their thermal conductivity and interfacial conductance in grain boundaries were measured using a time-domain thermoreflectance method. The interfacial conductance was estimated to be 1,010 and 4,892 MW/(m2·K) for UNCD/a-C:H and UNCD/a-C films, respectively. The reasons for the hydrogenated film having lower interfacial conductance than the non-hydrogenated film are 1) the reduced number of carriers that contribute to heat transport and 2) the hydrogen atoms, which are preferentially located at the grain boundaries and enhance phonon scattering.

  2. Development of twin cannons of thermal plasma

    International Nuclear Information System (INIS)

    Pena E, R.

    1996-01-01

    Today several service and transformation industries that generate hazardous wastes must implement programs in order to fulfill with requirements established by the present standardization. This problem is solved here for proposing the design and construction of a thermal plasma transferred torch with double cannon which is generated by an electric arc with a capacity of 50 k W, a regulable gas flow from 0-50 lt./min and thermal yield higher than 85 %. This equipment would be capable for degradating industrial and hospital wastes. (Author)

  3. Evaluation of mechanism of non-thermal plasma effect on the surface of polypropylene films for enhancement of adhesive and hemo compatible properties

    Energy Technology Data Exchange (ETDEWEB)

    Navaneetha Pandiyaraj, K., E-mail: dr.knpr@gmail.com [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L& T by pass, Chinniyam Palayam (post), Coimbatore-641062 (India); Deshmukh, R.R. [Department of Physics, Institute of Chemical Technology, Matunga, Mumbai-400 019 (India); Arunkumar, A.; Ramkumar, M.C. [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L& T by pass, Chinniyam Palayam (post), Coimbatore-641062 (India); Ruzybayev, I.; Ismat Shah, S. [Department of Physics and Astronomy, Department of Materials Science and Engineering, University of Delaware, 208 Dupont Hall, Newark (United States); Su, Pi-Guey [Department of Chemistry, Chinese Culture University, Taipei 111, Taiwan (China); Periayah, Mercy Halleluyah; Halim, A.S. [School of Medical Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia)

    2015-08-30

    Highlights: • Investigated the mechanism of effect of various gaseous plasma treatments on the surface properties of Polypropylene (PP) films. • The improvement in surface energy is basically due to the incorporation of polar functional groups onto the PP films. • The extent of surface modification and hydrophobic recovery depends upon the type of plasma forming gas. • Due to the significant morphological and chemical changes induced by the gaseous plasma treatment, improved the blood compatibility as well as adhesive strength of the PP films. - Abstract: The hydro-carbon based polymers have attracted attention of scientists for its use in bio-medical field as various implants due to inherent flexibility. However, they have poor surface properties; particularly they have low surface energy (SE). Hence, blood components (platelets, blood proteins, etc.)-polymer surface interaction is the major concern when it comes in contact with blood. Thus, surface modification is required to develop the perfect antithrombogenic property without affecting the materials bulk. The present study describes the improvement in adhesive and blood compatible properties of polypropylene (PP) by low temperature (non-thermal) plasma of various gases such as Ar, O{sub 2}, air and Ar + O{sub 2} for biomedical applications. The changes in surface morphological, chemical and hydrophilic modification induced by the gaseous plasma treatment were analyzed by atomic force microscopy (AFM), X-ray photo electron spectroscopy (XPS), electron spin resonance (ESR) spectroscopy and contact angle measurements, respectively. Moreover, the stability of plasma effect was also studied for the different storage conditions. Variation in adhesive strength of the plasma treated PP film was studied by T-Peel and Lap-Shear strength tests. The blood compatibility of the surface modified PP films was investigated by in vitro analysis. It was found that gaseous plasma treatment improved the blood compatibility

  4. Evaluation of mechanism of non-thermal plasma effect on the surface of polypropylene films for enhancement of adhesive and hemo compatible properties

    International Nuclear Information System (INIS)

    Navaneetha Pandiyaraj, K.; Deshmukh, R.R.; Arunkumar, A.; Ramkumar, M.C.; Ruzybayev, I.; Ismat Shah, S.; Su, Pi-Guey; Periayah, Mercy Halleluyah; Halim, A.S.

    2015-01-01

    Highlights: • Investigated the mechanism of effect of various gaseous plasma treatments on the surface properties of Polypropylene (PP) films. • The improvement in surface energy is basically due to the incorporation of polar functional groups onto the PP films. • The extent of surface modification and hydrophobic recovery depends upon the type of plasma forming gas. • Due to the significant morphological and chemical changes induced by the gaseous plasma treatment, improved the blood compatibility as well as adhesive strength of the PP films. - Abstract: The hydro-carbon based polymers have attracted attention of scientists for its use in bio-medical field as various implants due to inherent flexibility. However, they have poor surface properties; particularly they have low surface energy (SE). Hence, blood components (platelets, blood proteins, etc.)-polymer surface interaction is the major concern when it comes in contact with blood. Thus, surface modification is required to develop the perfect antithrombogenic property without affecting the materials bulk. The present study describes the improvement in adhesive and blood compatible properties of polypropylene (PP) by low temperature (non-thermal) plasma of various gases such as Ar, O 2 , air and Ar + O 2 for biomedical applications. The changes in surface morphological, chemical and hydrophilic modification induced by the gaseous plasma treatment were analyzed by atomic force microscopy (AFM), X-ray photo electron spectroscopy (XPS), electron spin resonance (ESR) spectroscopy and contact angle measurements, respectively. Moreover, the stability of plasma effect was also studied for the different storage conditions. Variation in adhesive strength of the plasma treated PP film was studied by T-Peel and Lap-Shear strength tests. The blood compatibility of the surface modified PP films was investigated by in vitro analysis. It was found that gaseous plasma treatment improved the blood compatibility as well

  5. Thermal radiation properties of PTFE plasma

    Science.gov (United States)

    Liu, Xiangyang; Wang, Siyu; Zhou, Yang; Wu, Zhiwen; Xie, Kan; Wang, Ningfei

    2017-06-01

    To illuminate the thermal transfer mechanism of devices adopting polytetrafluoroethylene (PTFE) as ablation materials, the thermal radiation properties of PTFE plasma are calculated and discussed based on local thermodynamic equilibrium (LTE) and optical thin assumptions. It is clarified that line radiation is the dominant mechanism of PTFE plasma. The emission coefficient shows an opposite trend for both wavelength regions divided by 550 nm at a temperature above 15 000 K. The emission coefficient increases with increasing temperature and pressure. Furthermore, it has a good log linear relation with pressure. Equivalent emissivity varies complexly with temperature, and has a critical point between 20 000 K to 25 000 K. The equivalent cross points of the average ionic valence and radiation property are about 10 000 K and 15 000 K for fully single ionization.

  6. Plasma Thermal Conversion of Methane to Acetylene

    International Nuclear Information System (INIS)

    Fincke, James Russell; Anderson, Raymond Paul; Hyde, Timothy Allen; Detering, Brent Alan; Wright, Randy Ben; Bewley, Randy Lee; Haggard, Delon C; Swank, William David

    2002-01-01

    This paper describes a re-examination of a known process for the direct plasma thermal conversion of methane to acetylene. Conversion efficiencies (% methane converted) approached 100% and acetylene yields in the 90-95% range with 2-4% solid carbon production were demonstrated. Specificity for acetylene was higher than in prior work. Improvements in conversion efficiency, yield, and specificity were due primarily to improved injector design and reactant mixing, and minimization of temperature gradients and cold boundary layers. At the 60-kilowatt scale cooling by wall heat transfer appears to be sufficient to quench the product stream and prevent further reaction of acetylene resulting in the formation of heavier hydrocarbon products or solid carbon. Significantly increasing the quenching rate by aerodynamic expansion of the products through a converging-diverging nozzle led to a reduction in the yield of ethylene but had little effect on the yield of other hydrocarbon products. While greater product selectivity for acetylene has been demonstrated, the specific energy consumption per unit mass of acetylene produced was not improved upon. A kinetic model that includes the reaction mechanisms resulting in the formation of acetylene and heavier hydrocarbons, through benzene, is described

  7. Cancer therapy using non-thermal atmospheric pressure plasma with ultra-high electron density

    International Nuclear Information System (INIS)

    Tanaka, Hiromasa; Mizuno, Masaaki; Toyokuni, Shinya; Maruyama, Shoichi; Kodera, Yasuhiro; Terasaki, Hiroko; Adachi, Tetsuo; Kato, Masashi; Kikkawa, Fumitaka; Hori, Masaru

    2015-01-01

    Cancer therapy using non-thermal atmospheric pressure plasma is a big challenge in plasma medicine. Reactive species generated from plasma are key factors for treating cancer cells, and thus, non-thermal atmospheric pressure plasma with high electron density has been developed and applied for cancer treatment. Various cancer cell lines have been treated with plasma, and non-thermal atmospheric plasma clearly has anti-tumor effects. Recent innovative studies suggest that plasma can both directly and indirectly affect cells and tissues, and this observation has widened the range of applications. Thus, cancer therapy using non-thermal atmospheric pressure plasma is promising. Animal experiments and understanding the mode of action are essential for clinical application in the future. A new academic field that combines plasma science, the biology of free radicals, and systems biology will be established

  8. Cancer therapy using non-thermal atmospheric pressure plasma with ultra-high electron density

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Hiromasa [Institute of Innovation for Future Society, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Center for Advanced Medicine and Clinical Research, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Mizuno, Masaaki [Center for Advanced Medicine and Clinical Research, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Toyokuni, Shinya [Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Maruyama, Shoichi [Department of Nephrology, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Kodera, Yasuhiro [Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Terasaki, Hiroko [Department of Ophthalmology, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Adachi, Tetsuo [Laboratory of Clinical Pharmaceutics, Gifu Pharmaceutical University, 501-1196 Gifu (Japan); Kato, Masashi [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Kikkawa, Fumitaka [Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Hori, Masaru [Institute of Innovation for Future Society, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2015-12-15

    Cancer therapy using non-thermal atmospheric pressure plasma is a big challenge in plasma medicine. Reactive species generated from plasma are key factors for treating cancer cells, and thus, non-thermal atmospheric pressure plasma with high electron density has been developed and applied for cancer treatment. Various cancer cell lines have been treated with plasma, and non-thermal atmospheric plasma clearly has anti-tumor effects. Recent innovative studies suggest that plasma can both directly and indirectly affect cells and tissues, and this observation has widened the range of applications. Thus, cancer therapy using non-thermal atmospheric pressure plasma is promising. Animal experiments and understanding the mode of action are essential for clinical application in the future. A new academic field that combines plasma science, the biology of free radicals, and systems biology will be established.

  9. Electron thermal transport in tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Konings, J A

    1994-11-30

    The process of fusion of small nuclei thereby releasing energy, as it occurs continuously in the sun, is essential for the existence of mankind. The same process applied in a controlled way on earth would provide a clean and an abundant energy source, and be the long term solution of the energy problem. Nuclear fusion requires an extremely hot (10{sup 8} K) ionized gas, a plasma, that can only be maintained if it is kept insulated from any material wall. In the so called `tokamak` this is achieved by using magnetic fields. The termal insulation, which is essential if one wants to keep the plasma at the high `fusion` temperature, can be predicted using basic plasma therory. A comparison with experiments in tokamaks, however, showed that the electron enery losses are ten to hundred times larger than this theory predicts. This `anomalous transport` of thermal energy implies that, to reach the condition for nuclear fusion, a fusion reactor must have very large dimensions. This may put the economic feasibility of fusion power in jeopardy. Therefore, in a worldwide collaboration, physicists study tokamak plasmas in an attempt to understand and control the energy losses. From a scientific point of view, the mechanisms driving anomalous transport are one of the challenges in fudamental plasma physics. In Nieuwegein, a tokamak experiment (the Rijnhuizen Tokamak Project, RTP) is dedicated to the study of anomalous transport, in an international collaboration with other laboratories. (orig./WL).

  10. Thermal condensation mode in a dusty plasma

    Indian Academy of Sciences (India)

    We find that the charge variability of the grain reduces the growth rate ..... Thus, in the short wavelength regime, thermal conductivity has stabilizing effect .... dynamics is retained, and the reason being that the momentum exchange of the grain ...

  11. Influence of plasma-induced energy deposition effects, the equation of state, thermal ionization, pulse shaping, and radiation on ion-beam-driven expansions of plane metal targets

    International Nuclear Information System (INIS)

    Long, K.A.; Tahir, N.A.

    1986-01-01

    In a previous paper by Long and Tahir [Phys. Fluids 29, 275 (1986)], the motion of plane targets irradiated by ion beams whose energy deposition was assumed to be independent of the ion energy, and the temperature and density of the plasma, was analyzed. In this paper, the analytic solution is extended in order to include the effects of a temperature-and density-dependent energy deposition as a result of electron excitation, an improved equation of state, thermal ionization, a pulse shape, and radiation losses. The change in the energy deposition with temperature and density leads to range shortening and an increased power deposition in the target. It is shown how the analytic theory can be used to analyze experiments to measure the enhanced energy deposition. In order to further analyze experiments, numerical simulations are presented which include the plasma-induced effects on the energy deposition. It is shown that since the change in the range is due to both decrease in density and the increase in temperature, it is not possible to separate these two effects in present experiments. Therefore, the experiments which measure the time-dependent energy of the ions emerging from the back side of a plane target do not as yet measure the energy loss as a function of the density and temperature of the plasma or of the energy of the ion, but only an averaged loss over certain ranges of these physical quantities

  12. Temperature of thermal plasma jets: A time resolved approach

    Energy Technology Data Exchange (ETDEWEB)

    Sahasrabudhe, S N; Joshi, N K; Barve, D N; Ghorui, S; Tiwari, N; Das, A K, E-mail: sns@barc.gov.i [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai - 400 094 (India)

    2010-02-01

    Boltzmann Plot method is routinely used for temperature measurement of thermal plasma jets emanating from plasma torches. Here, it is implicitly assumed that the plasma jet is 'steady' in time. However, most of the experimenters do not take into account the variations due to ripple in the high current DC power supplies used to run plasma torches. If a 3-phase transductor type of power supply is used, then the ripple frequency is 150 Hz and if 3- phase SCR based power supply is used, then the ripple frequency is 300 Hz. The electrical power fed to plasma torch varies at ripple frequency. In time scale, it is about 3.3 to 6.7 ms for one cycle of ripple and it is much larger than the arc root movement times which are within 0.2 ms. Fast photography of plasma jets shows that the luminosity of plasma jet also varies exactly like the ripple in the power supply voltage and thus with the power. Intensity of line radiations varies nonlinearly with the instantaneous power fed to the torch and the simple time average of line intensities taken for calculation of temperature is not appropriate. In this paper, these variations and their effect on temperature determination are discussed and a method to get appropriate data is suggested. With a small adaptation discussed here, this method can be used to get temperature profile of plasma jet within a short time.

  13. A two-dimensional nodal model with turbulent effects for the synthesis of Si nano-particles by inductively coupled thermal plasmas

    International Nuclear Information System (INIS)

    Colombo, V; Ghedini, E; Gherardi, M; Sanibondi, P; Shigeta, M

    2012-01-01

    Nano-particle synthesis by means of inductively coupled plasma torches is a material process of large technological interest. Numerous parameters are involved in the optimization of this process; hence the development of numerical models for the prediction of thermal and magneto-fluid dynamics fields, precursor powder trajectories and thermal history, as well as nano-particle formation and growth, is necessary for the up-scaling of these devices from laboratory batch production to an industrial continuous process. In this work, a two-dimensional (2D) discrete-type model (nodal model) for the analysis of nano-powder nucleation and growth is presented, taking into account convection, diffusion and turbulent effects on particle formation. Discrete-type models feature high precision and reveal a great deal of information useful for clarifying the nano-particle formation process. Using Si as the precursor material, 2D simulations of a nano-particle synthesis RF plasma apparatus with a reaction chamber are carried out. Good agreement is found when comparing results obtained with this model with those coming from a well-established nucleation-coupled moment method. Moreover, the extended amount of obtainable information that characterizes the nodal model is underlined. (paper)

  14. Thermal Expansion of Vacuum Plasma Sprayed Coatings

    Science.gov (United States)

    Raj, S V.; Palczer, A. R.

    2010-01-01

    Metallic Cu-8%Cr, Cu-26%Cr, Cu-8%Cr-1%Al, NiAl and NiCrAlY monolithic coatings were fabricated by vacuum plasma spray deposition processes for thermal expansion property measurements between 293 and 1223 K. The corrected thermal expansion, (DL/L(sub 0) varies with the absolute temperature, T, as (DL/L(sub 0) = A(T - 293)(sup 3) + BIT - 293)(sup 2) + C(T - 293) + D, where, A, B, C and D are thermal, regression constants. Excellent reproducibility was observed for all of the coatings except for data obtained on the Cu-8%Cr and Cu-26%Cr coatings in the first heat-up cycle, which deviated from those determined in the subsequent cycles. This deviation is attributed to the presence of residual stresses developed during the spraying of the coatings, which are relieved after the first heat-up cycle. In the cases of Cu-8%Cr and NiAl, the thermal expansion data were observed to be reproducible for three specimens. The linear expansion data for Cu-8% Cr and Cu-26%Cr agree extremely well with rule of mixture (ROM) predictions. Comparison of the data for the Cu-8%Cr coating with literature data for Cr and Cu revealed that the thermal expansion behavior of this alloy is determined by the Cu-rich matrix. The data for NiAl and NiCrAlY are in excellent agreement with published results irrespective of composition and the methods used for processing the materials. The implications of these results on coating GRCop-84 copper alloy combustor liners for reusable launch vehicles are discussed.

  15. Recent progress in the modelling of thermal plasma systems

    International Nuclear Information System (INIS)

    Xi Chen

    2002-01-01

    Plasma flow and heat transfer in thermal plasma systems are often of three-dimensional (3-D) features and cannot be well studied by use of a two-dimensional modelling approach. 3-D modelling studies are recently performed in our group. It is found that appreciable 3-D effects exist within non-transferred DC arc plasma torches even for the case with axisymmetrical external conditions. The key for the successful 3-D modelling of the non-transferred arc plasma torch is that the anode-nozzle wall is included in the computational domain. The predicted results are favorably compared with experimental observation. 3-D modelling of the plasma jets with lateral injection of particulate matter and its carrier gas also reveals distinct 3-D effects with the injection velocity and the distance between the carrier-gas injection-tube tip and the jet edge as critical parameters. The 3-D effects appreciably influence the trajectories and heating histories of particles injected into the plasma jet. (author)

  16. State of the art in medical applications using non-thermal atmospheric pressure plasma

    Science.gov (United States)

    Tanaka, Hiromasa; Ishikawa, Kenji; Mizuno, Masaaki; Toyokuni, Shinya; Kajiyama, Hiroaki; Kikkawa, Fumitaka; Metelmann, Hans-Robert; Hori, Masaru

    2017-12-01

    Plasma medical science is a novel interdisciplinary field that combines studies on plasma science and medical science, with the anticipation that understanding the scientific principles governing plasma medical science will lead to innovations in the field. Non-thermal atmospheric pressure plasma has been used for medical treatments, such as for cancer, blood coagulation, and wound healing. The interactions that occur between plasma and cells/tissues have been analyzed extensively. Direct and indirect treatment of cells with plasma has broadened the applications of non-thermal atmospheric pressure plasma in medicine. Examples of indirect treatment include plasma-assisted immune-therapy and plasma-activated medium. Controlling intracellular redox balance may be key in plasma cancer treatment. Animal studies are required to test the effectiveness and safety of these treatments for future clinical applications.

  17. Timescale and magnitude of plasma thermal energy loss before and during disruptions in JET

    International Nuclear Information System (INIS)

    Riccardo, V.; Loarte, A.

    2005-01-01

    In this paper we analyse and discuss the thermal energy loss dynamics before and during JET disruptions that occurred between 2002 and 2004 in discharges which reached >4.5 MJ of thermal energy. We observe the slow thermal energy transients with diamagnetic loops and the fast ones with electron cyclotron emission and soft x-ray diagnostics. For most disruption types in JET, the plasma thermal energy at the time of the thermal quench is substantially less than that of the full performance plasma, typically in the range of 10-50% depending on plasma conditions and disruption type. The exceptions to this observation are disruptions in plasmas with a strong internal transport barrier (ITB) and in discharges terminating in a pure vertical displacement event, in which the plasma conserves a very high energy content up to the thermal quench. These disruption types are very sudden, leaving little scope for the combined action of soft plasma landing strategies and intrinsic performance degradation, both requiring >500 ms to be effective, to decrease the available thermal energy. The characteristic time for the loss of energy from the main plasma towards the PFCs in the thermal quench of JET disruptions is in the range 0.05-3.0 ms. The shortest timescales are typical of disruptions caused by excessive pressure peaking in ITB discharges. The available thermal energy fraction and thermal quench duration observed in JET can be processed (with due caution) into estimates for the projected PFC lifetime of the ITER target

  18. Industrial implementation of plasma deposition using the expanding thermal plasma technique

    NARCIS (Netherlands)

    Sanden, van de M.C.M.; Oever, van den P.J.; Creatore, M.; Schaepkens, M.; Miebach, T.; Iacovangelo, C.D.; Bosch, R.C.M.; Bijker, M.D.; Evers, M.F.J.; Schram, D.C.; Kessels, W.M.M.

    2004-01-01

    Two successful industrial implementations of the expanding thermal plasma setup, a novel plasma source, obtaining high deposition rate are discussed. The Ar/O2/hexamethyldisiloxane and Ar/O2/octamethyl-cyclosiloxane-fed expanding thermal plasma setup is used to deposit scratch resistant silicone

  19. Transfer anisotropy effect in a turbulent plasma

    International Nuclear Information System (INIS)

    Bychenkov, V.Yu.; Gradov, O.M.; Silin, V.P.

    1982-01-01

    A theory is developed of transfer phenomena with pronounced ion-sound turbulence. A transfer anisotropy effect is observed which is due to the temperature gradient. The corresponding fluxes across the effective force vector generating the turbulence are found to be considerably greater than the longitudinal fluxes in a plasma with a comparatively low degree of nonisothermality. In a strongly nonisothermal plasma the suppression of transverse fluxes occurs, corresponding to the growth of thermal insulation of the current-carrying plasma filaments

  20. Effects of fluorine-based plasma treatment and thermal annealing on high-Al content AlGaN Schottky contact

    International Nuclear Information System (INIS)

    Liu Fang; Qin Zhixin

    2016-01-01

    Fluorine plasma treatment was used prior to the Schottky metal deposition on the undoped Al 0.45 Ga 0.55 N, which aimed at the solar-blind wavelength. After fluorine plasma treatment and before depositing the Ni/Au Schottky, the samples were thermal annealed in the N 2 gas at 400 °C. The reverse leakage current density of Al 0.45 Ga 0.55 N Schottky diode was reduced by 2 orders of magnitude at −10 V. The reverse leakage current density was reduced by 3 orders of magnitude after thermal annealing. Further capacitance–frequency analysis revealed that the fluorine-based plasma treatment reduces the surface states of AlGaN by one order of magnitude at different surface state energies. The capacitance–frequency analysis also proved that the concentration of carriers in AlGaN top is reduced through fluorine plasma treatment. (paper)

  1. What makes a thermal plasma suitable for hazardous waste disposal

    International Nuclear Information System (INIS)

    Benocci, R.; Florio, R.; Galassi, A.; Paolicchio, M.; Sindoni, E.

    1997-01-01

    The basic transport and thermodynamic characteristic of a thermal plasma are analysed in order to emphasize those properties that make a high-temperature source profitable and suitable over the conventional devices for hazardous waste treatment. In addition a survey of the basic reaction sequence and apparatus units is made together with the different approaches to thermal plasma waste treatments

  2. Monitoring non-thermal plasma processes for nanoparticle synthesis

    Science.gov (United States)

    Mangolini, Lorenzo

    2017-09-01

    Process characterization tools have played a crucial role in the investigation of dusty plasmas. The presence of dust in certain non-thermal plasma processes was first detected by laser light scattering measurements. Techniques like laser induced particle explosive evaporation and ion mass spectrometry have provided the experimental evidence necessary for the development of the theory of particle nucleation in silane-containing non-thermal plasmas. This review provides first a summary of these early efforts, and then discusses recent investigations using in situ characterization techniques to understand the interaction between nanoparticles and plasmas. The advancement of such monitoring techniques is necessary to fully develop the potential of non-thermal plasmas as unique materials synthesis and processing platforms. At the same time, the strong coupling between materials and plasma properties suggest that it is also necessary to advance techniques for the measurement of plasma properties while in presence of dust. Recent progress in this area will be discussed.

  3. Formation of electron-root radial electric field and its effect on thermal transport in LHD high Te plasma

    International Nuclear Information System (INIS)

    Matsuoka, Seikichi; Satake, Shinsuke; Takahashi, Hiromi; Yokoyama, Masayuki; Ido, Takeshi; Shimizu, Akihiro; Shimozuma, Takashi; Wakasa, Arimitsu; Murakami, Sadayoshi

    2013-01-01

    Neoclassical transport analyses have been performed for a high electron temperature LHD plasma with steep temperature gradient using a neoclassical transport simulation code, FORTEC-3D. It is shown that the large positive radial electric field is spontaneously formed at the core along with the increase in the electron temperature, while the neoclassical heat diffusivity remains almost unchanged. This indicates that the 1/ν-type increase expected in the neoclassical transport in helical plasmas can be avoided by the spontaneous formation of the radial electric field. At the same time, it is found that the experimentally estimated heat diffusivity is significantly reduced. This suggests that the formation process of the transport barrier in the high electron temperature plasma can be caused by the spontaneous formation of the radial electric field. (author)

  4. Development of plasma properties along thermal plasma jet generated by hybrid water-argon torch

    Czech Academy of Sciences Publication Activity Database

    Kavka, Tetyana; Hrabovský, Milan

    2002-01-01

    Roč. 52, supplement D (2002), s. 637-642 ISSN 0011-4626. [Symposium on Plasma Physics and Technology/20th./. Prague, 10.06.2002-13.06.2002] Institutional research plan: CEZ:AV0Z2043910 Keywords : thermal plasma, plasma jet, enthalpy probe Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.311, year: 2002

  5. Thermal Fatigue Behavior of Air-Plasma Sprayed Thermal Barrier Coating with Bond Coat Species in Cyclic Thermal Exposure

    Directory of Open Access Journals (Sweden)

    Ungyu Paik

    2013-08-01

    Full Text Available The effects of the bond coat species on the delamination or fracture behavior in thermal barrier coatings (TBCs was investigated using the yclic thermal fatigue and thermal-shock tests. The interface microstructures of each TBC showed a good condition without cracking or delamination after flame thermal fatigue (FTF for 1429 cycles. The TBC with the bond coat prepared by the air-plasma spray (APS method showed a good condition at the interface between the top and bond coats after cyclic furnace thermal fatigue (CFTF for 1429 cycles, whereas the TBCs with the bond coats prepared by the high-velocity oxygen fuel (HVOF and low-pressure plasma spray (LPPS methods showed a partial cracking (and/or delamination and a delamination after 780 cycles, respectively. The TBCs with the bond coats prepared by the APS, HVOF and LPPS methods were fully delaminated (>50% after 159, 36, and 46 cycles, respectively, during the thermal-shock tests. The TGO thickness in the TBCs was strongly dependent on the both exposure time and temperature difference tested. The hardness values were found to be increased only after the CFTF, and the TBC with the bond coat prepared by the APS showed the highest adhesive strength before and after the FTF.

  6. Antibacterial characteristics of thermal plasma spray system.

    Science.gov (United States)

    Goudarzi, M; Saviz, Sh; Ghoranneviss, M; Salar Elahi, A

    2018-03-15

    The objective of this study is to investigate antibacterial characteristics of a thermal plasma spray system. For this purpose, copper powder was coated on a handmade atmospheric plasma spraying system made by the stainless steel 316 substrate, which is preheated at different temperatures before spraying. A number of deposition characteristics such as antibacterial characteristics, adhesion strength and hardness of coating, was investigated. All of the spray parameters are fixed except the substrate temperature. The chemical composition was analyzed by X-ray diffraction (XRD). A scanning electron microscopy (SEM) and back scattering electron microscopy (BSE) were used to show the coating microstructure, its thickness and also the powder micrograph. The energy dispersive X-ray spectroscopy (EDX) was used to analyze the coating particles. Hardness of the deposition was examined by Vickers tester (HV0.1). Its adhesion strength was declared by cross cut tester (TQC). In addition, the percentage of bactericidal coating was evidenced with Staphylococcus aurous and Escherichia coli bacteria. Study results show that as the substrates temperature increases, the number of splats in the shape of pancake increases, the greatness and percentage of the deposition porosity both decrease. The increment of the substrate temperature leads to more oxidation and makes thicker dendrites on the splat. The enhancement of the substrate temperature also enlarges thickness and efficiency of coating. The interesting results are that antibacterial properties of coatings against the Escherichia coli are more than Staphylococcus aurous bacteria. However the bactericidal percentage of the coatings against Staphylococcus aurous and Escherichia coli bacteria roughly does not change with increasing the substrate temperature. Furthermore, by increment of the substrate temperature, coatings with both high adhesion and hardness are obtained. Accordingly, the temperature of substrate can be an

  7. Treatment of hazardous wastes by DC thermal plasma arc discharge

    International Nuclear Information System (INIS)

    Toru, Iwao; Yafang, Liu; Furuta, N.; Tsuginori, Inaba

    2001-01-01

    The temperature of the DC thermal plasma arc discharge is discussed, and examples of the waste treatment for the inorganic compounds such as fly ash, asbestos, and for the organic compounds such as the toxic dioxines and TBT by using the DC plasma arc discharge are shown. In addition, the plasma treatment by using a radiant power emitted from the DC plasma arc discharge is also shown as another new kind of ones. (authors)

  8. Numerical Modelling of Wood Gasification in Thermal Plasma Reactor

    Czech Academy of Sciences Publication Activity Database

    Hirka, Ivan; Živný, Oldřich; Hrabovský, Milan

    2017-01-01

    Roč. 37, č. 4 (2017), s. 947-965 ISSN 0272-4324 Institutional support: RVO:61389021 Keywords : Plasma modelling * CFD * Thermal plasma reactor * Biomass * Gasification * Syngas Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.355, year: 2016 https://link.springer.com/article/10.1007/s11090-017-9812-z

  9. Neutron irradiation effects on plasma facing materials

    Science.gov (United States)

    Barabash, V.; Federici, G.; Rödig, M.; Snead, L. L.; Wu, C. H.

    2000-12-01

    This paper reviews the effects of neutron irradiation on thermal and mechanical properties and bulk tritium retention of armour materials (beryllium, tungsten and carbon). For each material, the main properties affected by neutron irradiation are described and the specific tests of neutron irradiated armour materials under thermal shock and disruption conditions are summarized. Based on current knowledge, the expected thermal and structural performance of neutron irradiated armour materials in the ITER plasma facing components are analysed.

  10. Neutron irradiation effects on plasma facing materials

    International Nuclear Information System (INIS)

    Barabash, V.; Federici, G.; Roedig, M.; Snead, L.L.; Wu, C.H.

    2000-01-01

    This paper reviews the effects of neutron irradiation on thermal and mechanical properties and bulk tritium retention of armour materials (beryllium, tungsten and carbon). For each material, the main properties affected by neutron irradiation are described and the specific tests of neutron irradiated armour materials under thermal shock and disruption conditions are summarized. Based on current knowledge, the expected thermal and structural performance of neutron irradiated armour materials in the ITER plasma facing components are analysed

  11. Optimization of Non-Thermal Plasma Treatment in an In Vivo Model Organism.

    Directory of Open Access Journals (Sweden)

    Amanda Lee

    Full Text Available Non-thermal plasma is increasingly being recognized for a wide range of medical and biological applications. However, the effect of non-thermal plasma on physiological functions is not well characterized in in vivo model systems. Here we use a genetically amenable, widely used model system, Drosophila melanogaster, to develop an in vivo system, and investigate the role of non-thermal plasma in blood cell differentiation. Although the blood system in Drosophila is primitive, it is an efficient system with three types of hemocytes, functioning during different developmental stages and environmental stimuli. Blood cell differentiation in Drosophila plays an essential role in tissue modeling during embryogenesis, morphogenesis and also in innate immunity. In this study, we optimized distance and frequency for a direct non-thermal plasma application, and standardized doses to treat larvae and adult flies so that there is no effect on the viability, fertility or locomotion of the organism. We discovered that at optimal distance, time and frequency, application of plasma induced blood cell differentiation in the Drosophila larval lymph gland. We articulate that the augmented differentiation could be due to an increase in the levels of reactive oxygen species (ROS upon non-thermal plasma application. Our studies open avenues to use Drosophila as a model system in plasma medicine to study various genetic disorders and biological processes where non-thermal plasma has a possible therapeutic application.

  12. High resolution X-ray spectroscopy of thermal plasmas

    International Nuclear Information System (INIS)

    Canizares, C.R.

    1990-01-01

    This paper concentrates on reviewing highlights of the Focal Plane Crystal Spectrometer (FPCS) results on thermal plasmas, particularly supernova remnants (SNRs) and clusters of galaxies from the Einstein observatory. During Einstein's short but happy life, we made over 400 observations with the FPCS of 40 different objects. Three quarters of these were objects in which the emission was primarily from optically thin thermal plasma, primarily supernova remnants (SNRs) and clusters of galaxies. Thermal plasmas provide an excellent illustration of how spectral data, particularly high resolution spectral data, can be an important tool for probing the physical properties of astrophysical objects. (author)

  13. Destruction studies of hazardous wastes by thermal plasma

    International Nuclear Information System (INIS)

    Cota S, G.

    1998-01-01

    Plasma technology appears promising because its high degree of controllability, capability to process waste without the adverse effects of combustion, and a very wide temperature range of operation. The goal of this work was to develop a process for a high throughput system to turn hazardous waste into inert stable products, which can be safely stored and to greatly reduce air pollution relative to incineration. The experiments have shown that the thermal plasma reactor can provide a high degree of decomposition of CCl 4 , C 6 H 6 , C 2 Cl 4 and commercial oil at low gas input speeds, with modest power requirements. Decomposition of 99.9999 % has been obtained in our laboratory and all the organic components are decomposed in base molecules (C, CO, CO 2 , H 2 , HCl). The analysis of exhaust gases was made by using a mass filter quadrupole. The equipment consist of a cylindrical reactor hermetically sealed, double-walled and water-cooled container made of special steel, this container in halt the crucible which serves to receive the waste materials. The whole system is designed for a maximal internal temperature of 2000 Centigrade. The gaseous result components of the material are transferred to a scrubber unit through an exit arranged on the top of reactor. The thermal efficiency evaluation of the plasma torch was also realized, obtaining a reasonable agreement between measurements and predictions in temperature profiles. (Author)

  14. Waste cell phone recycling by thermal plasma techniques

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, T.; Kunimoto, N.; Abe, S. [Chuo Univ., Bunkyo-Ku, Tokyo (Japan). Dept. of Electrical, Electronics, and Communication Engineering; Li, O.L.; Chang, J.S.; Ruj, B. [McMaster Univ., Hamilton, ON (Canada). Faculty of Engineering

    2010-07-01

    Due to the cost-effective nature of wireless networks, the number of cell phones used around the world has increased significantly. However, a major problem of this technology is the generation of a great deal of complex electronics wastes, such as cell phones. The typical average life of a cell phone is around 2 years. Therefore, inexpensive recycling techniques must be developed for valuable resources such as real metals and plastics used in cell phones. Thermal plasma has been used for many different waste treatments since it has the capability to detoxify waste by-products. This paper presented a preliminary investigation for cell phone recycling by a thermal plasma technology. Recyclable resource material was identified by neutron activation analyses. Then, the cell phone waste was first crashed and treated by Ar twin torch plasmas to remove the majority of organic materials. The paper described the experimental apparatus and results. It was concluded that styrene (C{sub 8}H{sub 8}) and benzene (C{sub 6}H{sub 6}O) may be two major by-products in on-line by-products gas. The molecule becomes a much heavier by-product gas after cooling down. 6 refs., 6 figs.

  15. Anisotropic Thermal Diffusivities of Plasma-Sprayed Thermal Barrier Coatings

    Science.gov (United States)

    Akoshima, Megumi; Takahashi, Satoru

    2017-09-01

    Thermal barrier coatings (TBCs) are used to shield the blades of gas turbines from heat and wear. There is a pressing need to evaluate the thermal conductivity of TBCs in the thermal design of advanced gas turbines with high energy efficiency. These TBCs consist of a ceramic-based top coat and a bond coat on a superalloy substrate. Usually, the focus is on the thermal conductivity in the thickness direction of the TBC because heat tends to diffuse from the surface of the top coat to the substrate. However, the in-plane thermal conductivity is also important in the thermal design of gas turbines because the temperature distribution within the turbine cannot be ignored. Accordingly, a method is developed in this study for measuring the in-plane thermal diffusivity of the top coat. Yttria-stabilized zirconia top coats are prepared by thermal spraying under different conditions. The in-plane and cross-plane thermal diffusivities of the top coats are measured by the flash method to investigate the anisotropy of thermal conduction in a TBC. It is found that the in-plane thermal diffusivity is higher than the cross-plane one for each top coat and that the top coats have significantly anisotropic thermal diffusivity. The cross-sectional and in-plane microstructures of the top coats are observed, from which their porosities are evaluated. The thermal diffusivity and its anisotropy are discussed in detail in relation to microstructure and porosity.

  16. Stationary self-focusing of Gaussian laser beam in relativistic thermal quantum plasma

    International Nuclear Information System (INIS)

    Patil, S. D.; Takale, M. V.

    2013-01-01

    In the present paper, we have employed the quantum dielectric response in thermal quantum plasma to model relativistic self-focusing of Gaussian laser beam in a plasma. We have presented an extensive parametric investigation of the dependence of beam-width parameter on distance of propagation in relativistic thermal quantum plasma. We have studied the role of Fermi temperature in the phenomenon of self-focusing. It is found that the quantum effects cause much higher oscillations of beam-width parameter and better relativistic focusing of laser beam in thermal quantum plasma in comparison with that in the relativistic cold quantum plasma and classical relativistic plasma. Our computations show more reliable results in comparison to the previous works

  17. Paracetamol degradation in aqueous solution by non-thermal plasma

    Science.gov (United States)

    Baloul, Yasmine; Aubry, Olivier; Rabat, Hervé; Colas, Cyril; Maunit, Benoît; Hong, Dunpin

    2017-08-01

    This study deals with paracetamol degradation in water using a non-thermal plasma (NTP) created by a dielectric barrier discharge (DBD). The effects of the NTP operating conditions on the degradation were studied, showing that the treatment efficiency of the process was highly dependent on the electrical parameters and working gas composition in the reactor containing the aqueous solution. A conversion rate higher than 99% was reached with an energy yield of 12 g/kWh. High resolution mass spectrometry (HRMS) measurements showed that the main species produced in water during the process were nitrogen compounds, carboxylic acids and aromatic compounds. Contribution to the topical issue "The 15th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XV)", edited by Nicolas Gherardi and Tomáš Hoder

  18. Dispersion in thermal plasma including arbitrary degeneracy and quantum recoil

    International Nuclear Information System (INIS)

    Mushtaq, A.; Melrose, D.B.

    2012-01-01

    The longitudinal response function for a thermal electron gas was calculated including two quantum effects exactly, degeneracy and the quantum recoil. The Fermi-Dirac distribution was expanded in powers of a parameter that is small in the non-degenerate limit and the response function was evaluated in terms of the conventional plasma dispersion function to arbitrary order in this parameter. The infinite sum was performed in terms of poly logarithms in the long-wavelength and quasi-static limits, giving results that apply for arbitrary degeneracy. The results were applied to the dispersion relations for Langmuir waves and to screening, reproducing known results in the non-degenerate and completely degenerate limits], and generalizing them to arbitrary degeneracy. The occupation number for the completely degenerate limit is shown. The importance of the results regarding to semiconductor plasmas were highlighted. (orig./A.B.)

  19. Non-Thermal Sanitation By Atmospheric Pressure Plasma, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop a non-thermal technology based on atmospheric-pressure (AP) cold plasma to sanitize foods, food packaging materials, and other hardware...

  20. Effect of thermal 3He minorities on knock-on tail formation and the resulting neutron emission spectrum modification in deuterium-tritium plasmas

    International Nuclear Information System (INIS)

    Matsuura, H; Nakao, Y; Nakamura, M; Mitarai, O

    2011-01-01

    The knock-on tail formations in fuel-ion velocity distribution functions by energetic alpha particles (by the T(d,n) 4 He reaction) and protons (by the D(d,p)T and 3 He(d,p) 4 He reactions) are investigated by simultaneously solving the Boltzmann-Fokker-Planck (BFP) equations for deuteron, triton, 3 He, alpha particle and proton in an ITER-like (DT) plasma admixed with a small amount of 3 He. As a result of the 3 He inclusion, a fraction of the transferred energy from energetic ions to thermal deuterons and tritons via nuclear plus interference (NI) scattering is reduced. Owing to the NI scattering of the energetic protons by fuel ions, the latter are knocked up to higher energies. The knocking-up effect of fuel ions is enhanced with increasing 3 He concentration. It is shown that if 3 He with relative concentration of 4.2%, i.e. n 3 He /n e =0.042, is included in T e = 20 keV, n e = 9.5 x 10 19 m -3 plasma, the magnitude of the knock-on tail in deuteron distribution function in 300 keV-3 MeV energy range is reduced by about 15% from the value when 3 He is not externally supplied. Such knock-on tail reduction also results in alternation of the non-Gaussian neutron emission spectrum with energies less than ∼13 MeV and above ∼15 MeV.

  1. Thermal fatigue behavior of thermal barrier coatings by air plasma spray

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Han Sang; Kim, Eui Hyun [Korea Electric Power Research Institute, Daejeon (Korea, Republic of); Lee, Jung Hyuk [Korea Plant Service and Engineering Co. Ltd., Incheon (Korea, Republic of)

    2008-06-15

    Effects of top coat morphology and thickness on thermal fatigue behavior of Thermal Barrier Coatings (TBC) were investigated in this study. Thermal fatigue tests were conducted on three coating specimens with different top coat morphology and thickness, and then the test data were compared via microstructures, cycles to failure, and fracture surfaces. In the air plasma spray specimens (APS1, APS2), top coat were 200 and 300 {mu}m respectively. The thickness of top coat was about 700 {mu}m in the Perpendicular Cracked Specimen (PCS). Under thermal fatigue condition at 1,100 .deg. C, the cycles to top coat failure of APS1, APS2, and PCS were 350, 560 and 480 cycles, respectively. The cracks were initiated at the interface of top coat and Thermally Grown Oxide (TGO) and propagated into TGO or top coat as the number of thermal fatigue cycles increased. For the PCS specimen, additive cracks were initiated and propagated at the starting points of perpendicular cracks in the top coat. Also, the thickness of TGO and the decrease of aluminium concentration in bond coat do not affect the cycles to failure.

  2. Preliminary experiments on wastes degradation by thermal plasma

    International Nuclear Information System (INIS)

    Cota S, G.; Pacheco S, J.; Segovia R, A.; Pena E, R.; Merlo S, L.

    1996-01-01

    This work presents the fundamental aspects involved in the installation and start up of an experimental equipment for the hazardous wastes degradation using the thermal plasma technology. It is mentioned about the form in which the thermal plasma is generated and the characteristics that its make to be an appropriate technology for the hazardous wastes degradation. Just as the installed structures for to realize the experiments and results of the first studies on degradation, using nylon as problem sample. (Author)

  3. Monitoring system for thermal plasma; Sistema de monitoreo para plasma termico

    Energy Technology Data Exchange (ETDEWEB)

    Romero G, M.; Vilchis P, A.E. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1999-07-01

    In the Thermal plasma applications laboratory it has been the degradation project of oils for isolation in transformers. These are a very hazardous residues and at this time in the country they are stored in metal barrels. It has been the intention to undergo the oils to plasma for degradate them to non-hazardous residues. The system behavior must be monitored to establish the thermal plasma behavior. (Author)

  4. Multi-Directional Optical Diagnostics of Thermal Plasma Jets

    Czech Academy of Sciences Publication Activity Database

    Hlína, Jan; Chvála, František; Šonský, Jiří; Gruber, Jan

    2008-01-01

    Roč. 19, č. 1 (2008), s. 1-6 ISSN 0957-0233 R&D Projects: GA ČR(CZ) GA202/05/0728 Institutional research plan: CEZ:AV0Z20570509 Keywords : thermal plasma jet * optical diagnostics * Radon transform Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.493, year: 2008

  5. Effects of thermal regime on ovarian maturation and plasma sex steroids in farmed white sturgeon, Acipenser transmontanus

    Science.gov (United States)

    Webb, M.A.H.; Van Eenennaam, J. P.; Feist, G.W.; Linares-Casenave, J.; Fitzpatrick, M.S.; Schreck, C.B.; Doroshov, S.I.

    2001-01-01

    Recently, commercial aquaculture farms in Northern California have exposed gravid, cultured white sturgeon females to cold water (12 ?? 1??C) throughout the late phase of vitellogenesis and ovarian follicle maturation resulting in improved ovulation rates and egg quality. However, the optimum timing for transfer of broodfish to the cold water and the capacity of transferred broodfish to maintain reproductive competence over an extended time in cold water had not been evaluated. Gravid white sturgeon females that have been raised at water temperatures of 16-20??C were transported to either cold water (12 ?? 1??C; Group 1) in November 1997 or maintained in ambient water temperatures (10-19??C; Group 2) until early spring. In March 1998, half of the fish in Group 2 had regressed ovaries, but the remaining females had intact ovarian follicles and were transported to the cold water. Ovarian follicles and blood were collected from females until they reached the stage of spawning readiness (determined by germinal vesicle position and an oocyte maturation assay) or underwent ovarian regression. Exposure of gravid sturgeon females to ambient water temperatures (14.5 ?? 2.3??C, mean ?? S.D.) from October to March led to a decrease in plasma sex steroids and a high incidence of ovarian regression in fish with a more advanced stage of oocyte development. Transfer of females with intact ovarian follicles to cold water (12 ?? 1??C) in the fall or early spring resulted in normal ovarian development in the majority of females. Holding females in cold water does not seem to override their endogenous reproductive rhythms but extends their capacity to maintain oocyte maturational competence over a longer period of time. A temperature-sensitive phase in ovarian development may occur during the transition from vitellogenic growth to oocyte maturation, and the degree and timing of sensitivity to environmental temperature are dependent on the female's endogenous reproductive rhythm

  6. Effect of ambient pressure on the crystalline phase of nano TiO2 particles synthesized by a dc thermal plasma reactor

    International Nuclear Information System (INIS)

    Banerjee, I.; Karmakar, Soumen; Kulkarni, Naveen V.; Nawale, Ashok B.; Mathe, V. L.; Das, A. K.; Bhoraskar, S. V.

    2010-01-01

    The synthesis of nanoparticles of titanium dioxide (TiO 2 ) with varying percentages of anatase and rutile phases is reported. This was achieved by controlling the operating pressure in a transferred-arc, direct current thermal plasma reactor in which titanium vapors are evaporated, and then exposed to ambient oxygen. The average particle size remained around 15 nm in each case. The crystalline structure of the as-synthesized nanoparticles of TiO 2 was studied with X-ray diffraction analysis; whereas the particle morphology was investigated with the help of transmission electron microscopy. The precursor species responsible for the growth of these nanoparticles was studied with the help of optical emission spectroscopy. As inferred from the X-ray diffraction analysis, the relative abundance of anatase TiO 2 was found to be dominant when synthesized at 760 Torr, and the same showed a decreasing trend with decreasing chamber pressure. The study also reveals that anatase TiO 2 is a more effective photocatalytic agent in degrading methylene blue by comparison to its rutile phase.

  7. Formation of thermal eddies during rf heating of plasma

    International Nuclear Information System (INIS)

    Motley, R.W.; Hooke, W.M.; Anania, G.

    1979-07-01

    Moderate power (approx.1 kW) excitation of lower hybrid waves in a linear plasma column is found to increase the reflectivity of the phased waveguide exciter and to change the vertical position of the resonance cone. Probing of the plasma near the mouth of the waveguide reveals that the increased reflection results from an undulation in the plasma surface. We present evidence that this surface distortion is driven by thermal eddies associated with asymmetrical electron heating

  8. Modeling of thermalization phenomena in coaxial plasma accelerators

    Science.gov (United States)

    Subramaniam, Vivek; Panneerchelvam, Premkumar; Raja, Laxminarayan L.

    2018-05-01

    Coaxial plasma accelerators are electromagnetic acceleration devices that employ a self-induced Lorentz force to produce collimated plasma jets with velocities ~50 km s‑1. The accelerator operation is characterized by the formation of an ionization/thermalization zone near gas inlet of the device that continually processes the incoming neutral gas into a highly ionized thermal plasma. In this paper, we present a 1D non-equilibrium plasma model to resolve the plasma formation and the electron-heavy species thermalization phenomena that take place in the thermalization zone. The non-equilibrium model is based on a self-consistent multi-species continuum description of the plasma with finite-rate chemistry. The thermalization zone is modelled by tracking a 1D gas-bit as it convects down the device with an initial gas pressure of 1 atm. The thermalization process occurs in two stages. The first is a plasma production stage, associated with a rapid increase in the charged species number densities facilitated by cathode surface electron emission and volumetric production processes. The production stage results in the formation of a two-temperature plasma with electron energies of ~2.5 eV in a low temperature background gas of ~300 K. The second, a temperature equilibration stage, is characterized by the energy transfer between the electrons and heavy species. The characteristic length scale for thermalization is found to be comparable to axial length of the accelerator thus putting into question the equilibrium magnetohydrodynamics assumption used in modeling coaxial accelerators.

  9. Simulations of planar non-thermal plasma assisted ignition at atmospheric pressure

    KAUST Repository

    Casey, Tiernan A.; Han, Jie; Belhi, Memdouh; Arias, Paul G.; Bisetti, Fabrizio; Im, Hong G.; Chen, Jyh Yuan

    2016-01-01

    neutrals and ions to the non-thermal electrons. A two-temperature plasma mechanism describing gas phase combustion, excitation of neutral species, and high-energy electron kinetics is employed to account for non-thermal effects. Charged species transported

  10. Electron cyclotron emission from thermal plasmas

    International Nuclear Information System (INIS)

    Fidone, I.; Granata, G.

    1978-02-01

    Electron cyclotron radiation from a warm inhomogeneous plasma is investigated. A direct calculation of the emissive power of a plasma slab is performed using Rytov's method and the result is compared with the solution of the transfer equation. It is found that, for arbitrary directions of emission, the two results differ, which reflects the fact that Kirchhoff's law is not generally obeyed

  11. On thermalization of electron-positron-photon plasma

    Energy Technology Data Exchange (ETDEWEB)

    Siutsou, I. A., E-mail: siutsou@icranet.org [CAPES–ICRANet program, ICRANet–Rio, CBPF 22290-180, Rua Dr. Xavier Sigaud, 150, Urca, Rio de Janeiro, RJ (Brazil); Aksenov, A. G. [Institute for Computer-Aided Design, Russian Academy of Sciences 123056, 2nd Brestskaya st., 19/18, Moscow (Russian Federation); Vereshchagin, G. V. [ICRANet 65122, p.le della Republica, 10, Pescara (Italy)

    2015-12-17

    Recently a progress has been made in understanding thermalization mechanism of relativistic plasma starting from a non-equilibrium state. Relativistic Boltzmann equations were solved numerically for homogeneous isotropic plasma with collision integrals for two- and three-particle interactions calculated from the first principles by means of QED matrix elements. All particles were assumed to fulfill Boltzmann statistics. In this work we follow plasma thermalization by accounting for Bose enhancement and Pauli blocking in particle interactions. Our results show that particle in equilibrium reach Bose-Einstein distribution for photons, and Fermi-Dirac one for electrons, respectively.

  12. On thermalization of electron-positron-photon plasma

    Science.gov (United States)

    Siutsou, I. A.; Aksenov, A. G.; Vereshchagin, G. V.

    2015-12-01

    Recently a progress has been made in understanding thermalization mechanism of relativistic plasma starting from a non-equilibrium state. Relativistic Boltzmann equations were solved numerically for homogeneous isotropic plasma with collision integrals for two- and three-particle interactions calculated from the first principles by means of QED matrix elements. All particles were assumed to fulfill Boltzmann statistics. In this work we follow plasma thermalization by accounting for Bose enhancement and Pauli blocking in particle interactions. Our results show that particle in equilibrium reach Bose-Einstein distribution for photons, and Fermi-Dirac one for electrons, respectively.

  13. Effects of O2 plasma post-treatment on ZnO: Ga thin films grown by H2O-thermal ALD

    Science.gov (United States)

    Lee, Yueh-Lin; Chuang, Jia-Hao; Huang, Tzu-Hsuan; Ho, Chong-Long; Wu, Meng-Chyi

    2013-03-01

    Transparent conducting oxides have been widely employed in optoelectronic devices using the various deposition methods such as sputtering, thermal evaporator, and e-gun evaporator technologies.1-3 In this work, gallium doped zinc oxide (ZnO:Ga) thin films were grown on glass substrates via H2O-thermal atomic layer deposition (ALD) at different deposition temperatures. ALD-GZO thin films were constituted as a layer-by-layer structure by stacking zinc oxides and gallium oxides. Diethylzinc (DEZ), triethylgallium (TEG) and H2O were used as zinc, gallium precursors and oxygen source, respectively. Furthermore, we investigated the influences of O2 plasma post-treatment power on the surface morphology, electrical and optical property of ZnO:Ga films. As the result of O2 plasma post-treatment, the characteristics of ZnO:Ga films exhibit a smooth surface, low resistivity, high carrier concentration, and high optical transmittance in the visible spectrum. However, the transmittance decreases with O2 plasma power in the near- and mid-infrared regions.

  14. Non-thermal atmospheric-pressure plasma possible application in wound healing.

    Science.gov (United States)

    Haertel, Beate; von Woedtke, Thomas; Weltmann, Klaus-Dieter; Lindequist, Ulrike

    2014-11-01

    Non-thermal atmospheric-pressure plasma, also named cold plasma, is defined as a partly ionized gas. Therefore, it cannot be equated with plasma from blood; it is not biological in nature. Non-thermal atmospheric-pressure plasma is a new innovative approach in medicine not only for the treatment of wounds, but with a wide-range of other applications, as e.g. topical treatment of other skin diseases with microbial involvement or treatment of cancer diseases. This review emphasizes plasma effects on wound healing. Non-thermal atmospheric-pressure plasma can support wound healing by its antiseptic effects, by stimulation of proliferation and migration of wound relating skin cells, by activation or inhibition of integrin receptors on the cell surface or by its pro-angiogenic effect. We summarize the effects of plasma on eukaryotic cells, especially on keratinocytes in terms of viability, proliferation, DNA, adhesion molecules and angiogenesis together with the role of reactive oxygen species and other components of plasma. The outcome of first clinical trials regarding wound healing is pointed out.

  15. Thermal diffusivity effect in opto-thermal skin measurements

    International Nuclear Information System (INIS)

    Xiao, P; Imhof, R E; Cui, Y; Ciortea, L I; Berg, E P

    2010-01-01

    We present our latest study on the thermal diffusivity effect in opto-thermal skin measurements. We discuss how thermal diffusivity affects the shape of opto-thermal signal, and how to measure thermal diffusivity in opto-thermal measurements of arbitrary sample surfaces. We also present a mathematical model for a thermally gradient material, and its corresponding opto-thermal signal. Finally, we show some of our latest experimental results of this thermal diffusivity effect study.

  16. Novel Prospects for Plasma Spray-Physical Vapor Deposition of Columnar Thermal Barrier Coatings

    Science.gov (United States)

    Anwaar, Aleem; Wei, Lianglinag; Guo, Qian; Zhang, Baopeng; Guo, Hongbo

    2017-12-01

    Plasma spray-physical vapor deposition (PS-PVD) is an emerging coating technique that can produce columnar thermal barrier coatings from vapor phase. Feedstock treatment at the start of its trajectory in the plasma torch nozzle is important for such vapor-phase deposition. This study describes the effects of the plasma composition (Ar/He) on the plasma characteristics, plasma-particle interaction, and particle dynamics at different points spatially distributed inside the plasma torch nozzle. The results of calculations show that increasing the fraction of argon in the plasma gas mixture enhances the momentum and heat flow between the plasma and injected feedstock. For the plasma gas combination of 45Ar/45He, the total enthalpy transferred to a representative powder particle inside the plasma torch nozzle is highest ( 9828 kJ/kg). Moreover, due to the properties of the plasma, the contribution of the cylindrical throat, i.e., from the feed injection point (FIP) to the start of divergence (SOD), to the total transferred energy is 69%. The carrier gas flow for different plasma gas mixtures was also investigated by optical emission spectroscopy (OES) measurements of zirconium emissions. Yttria-stabilized zirconia (YSZ) coating microstructures were produced when using selected plasma gas compositions and corresponding carrier gas flows; structural morphologies were found to be in good agreement with OES and theoretical predictions. Quasicolumnar microstructure was obtained with porosity of 15% when applying the plasma composition of 45Ar/45He.

  17. Effect of surface properties of NiFe2O4 nanoparticles synthesized by dc thermal plasma route on antimicrobial activity

    Science.gov (United States)

    Bhosale, S. V.; Ekambe, P. S.; Bhoraskar, S. V.; Mathe, V. L.

    2018-05-01

    The present work reports the role of surface properties of NiFe2O4 nanoparticles on the antimicrobial activity. The NiFe2O4 nanoparticles were synthesized by gas phase condensation and chemical co-precipitation route. These nanoparticles were extensively investigated using X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and electro-kinetic property measurements. The HRTEM was used to analyze surface morphology of nickel ferrite nanoparticles obtained by two different routes. Electro-kinetic properties of the nanoparticles under investigation were recorded, analyzed and correlated with the antimicrobial properties. It was observed that nickel ferrite nanoparticles synthesized by thermal plasma route (NFOTP) formed highly stable colloidal solution as compared to chemically synthesized (NFOCP), as the later tends to agglomerate due to low surface charge. The antimicrobial activity of NiFe2O4 nanoparticles were investigated on two Gram positive bacteria Staphylococcus aureus and Streptococcus pyogenes, two Gram negative bacteria Escherichia coli and Salmonella typhimurium and one fungal species Candida albicans. It was noted that the surface properties of NiFe2O4 particles have revealing effect on the antimicrobial activity. The NFOTP nanoparticles showed significant activity for gram negative E. coli bacteria however no activity was observed for other bacteria's and fungi under study. Moreover NFOCP particles did not show any significant activity for both bacteria's and fungi. Further, antimicrobial activity of nickel ferrite nanoparticles were studied even for different concentration to obtain the minimum inhibition concentration (MIC).

  18. Non-thermal Plasma Exposure Rapidly Attenuates Bacterial AHL-Dependent Quorum Sensing and Virulence

    Science.gov (United States)

    Flynn, Padrig B.; Busetti, Alessandro; Wielogorska, Ewa; Chevallier, Olivier P.; Elliott, Christopher T.; Laverty, Garry; Gorman, Sean P.; Graham, William G.; Gilmore, Brendan F.

    2016-01-01

    The antimicrobial activity of atmospheric pressure non-thermal plasma has been exhaustively characterised, however elucidation of the interactions between biomolecules produced and utilised by bacteria and short plasma exposures are required for optimisation and clinical translation of cold plasma technology. This study characterizes the effects of non-thermal plasma exposure on acyl homoserine lactone (AHL)-dependent quorum sensing (QS). Plasma exposure of AHLs reduced the ability of such molecules to elicit a QS response in bacterial reporter strains in a dose-dependent manner. Short exposures (30–60 s) produce of a series of secondary compounds capable of eliciting a QS response, followed by the complete loss of AHL-dependent signalling following longer exposures. UPLC-MS analysis confirmed the time-dependent degradation of AHL molecules and their conversion into a series of by-products. FT-IR analysis of plasma-exposed AHLs highlighted the appearance of an OH group. In vivo assessment of the exposure of AHLs to plasma was examined using a standard in vivo model. Lettuce leaves injected with the rhlI/lasI mutant PAO-MW1 alongside plasma treated N-butyryl-homoserine lactone and n-(3-oxo-dodecanoyl)-homoserine lactone, exhibited marked attenuation of virulence. This study highlights the capacity of atmospheric pressure non-thermal plasma to modify and degrade AHL autoinducers thereby attenuating QS-dependent virulence in P. aeruginosa. PMID:27242335

  19. Plasma processes and film growth of expanding thermal plasma deposited textured zinc oxide

    NARCIS (Netherlands)

    Groenen, R.; Linden, J.L.; Sanden, van de M.C.M.

    2005-01-01

    Plasma processes and film growth of textured zinc oxide deposited from oxygen and diethyl zinc utilizing expanding thermal argon plasma created by a cascaded arc is discussed. In all conditions explored, an excess of argon ions and low temperature electrons is available, which represent the

  20. The structure and thermal properties of plasma-sprayed beryllium for the International Thermonuclear Experimental Reactor (ITER)

    International Nuclear Information System (INIS)

    Castro, R.G.; Bartlett, A.; Elliott, K.E.; Hollis, K.J.

    1996-01-01

    Plasma spraying is being studied for in situ repair of damaged Be and W plasma facing surfaces for ITER, the next generation magnetic fusion energy device, and is also being considered for fabricating Be and W plasma-facing components for the first wall of ITER. Investigators at LANL's Beryllium Atomization and Thermal Spray Facility have concentrated on investigating the structure-property relation between as-deposited microstructures of plasma sprayed Be coatings and resulting thermal properties. In this study, the effect of initial substrate temperature on resulting thermal diffusivity of Be coatings and the thermal diffusivity at the coating/Be substrate interface (interface thermal resistance) was investigated. Results show that initial Be substrate temperatures above 600 C can improve the thermal diffusivity of the Be coatings and minimize any thermal resistance at the interface between the Be coating and Be substrate

  1. Statistics of turbulent structures in a thermal plasma jet

    Czech Academy of Sciences Publication Activity Database

    Hlína, Jan; Šonský, Jiří; Něnička, Václav; Zachar, Andrej

    2005-01-01

    Roč. 38, - (2005), s. 1760-1768 ISSN 0022-3727 R&D Projects: GA AV ČR(CZ) IAA1057202; GA ČR(CZ) GA202/05/0728 Institutional research plan: CEZ:AV0Z20570509 Keywords : turbulent structures * thermal plasma jet Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.957, year: 2005

  2. Spatial Dynamics of Coherent Structures in a Thermal Plasma Jet

    Czech Academy of Sciences Publication Activity Database

    Hlína, Jan; Sekerešová, Zuzana; Šonský, Jiří

    2008-01-01

    Roč. 36, č. 4 (2008), s. 1066-1067 ISSN 0093-3813 R&D Projects: GA ČR GA202/05/0728 Institutional research plan: CEZ:AV0Z20570509 Keywords : charge-coupled-device (CCD) camera * coherent structure * thermal plasma jet * turbulence Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.447, year: 2008

  3. Thermal fluctuations and critical behavior in a magnetized, anisotropic plasma

    International Nuclear Information System (INIS)

    Hazeltine, R. D.; Mahajan, S. M.

    2013-01-01

    Thermal fluctuations in a magnetized, anisotropic plasma are studied by applying standard methods, based on the Einstein rule, to the known thermodynamic potential of the system. It is found in particular that magnetic fluctuations become critical when the anisotropy p ∥ −p ⊥ changes sign. By examining the critical region, additional insight on the equations of state for near-critical anisotropic plasma is obtained

  4. Reflection of oblique electron thermal modes in an inhomogeneous plasma

    International Nuclear Information System (INIS)

    Ohnuma, T.; Watanabe, T.; Sanuki, H.

    1980-04-01

    In an inhomogeneous magnetoplasma, reflection of an oblique electron thermal mode radiated from a local source is investigated experimentally and theoretically near the electron plasma frequency layer. The experimental observation of reflection in the lower plasma density region than the f sub(p)-layer is found to be in qualitative accord with the theoretical reflection, which is obtained from a kinetic theory in an inhomogeneous magnetoplasma. The reflection of the thermal mode is also compared with that of an electromagnetic mode at the f sub(p)-layer. (author)

  5. Plasma thermal energy transport: theory and experiments

    International Nuclear Information System (INIS)

    Coppi, B.

    Experiments on the transport across the magnetic field of electron thermal energy are reviewed (Alcator, Frascati Torus). In order to explain the experimental results, a transport model is described that reconfirmed the need to have an expression for the local diffusion coefficient with a negative exponent of the electron temperature

  6. Remelting of metallurgical fines using thermal plasma

    International Nuclear Information System (INIS)

    Vicente, L.C.; Neto F, J.B.F.; Bender, O.W.; Collares, M.P.

    1992-01-01

    A plasma furnace was developed for remelting of ferro alloys and silicon fines. The furnace capacity was about 4 Kg of silicon and power about 50 kW. The fine (20 to 100 mesh) was fed into the furnace directly at the high temperature zone. This system was tested for remelting silicon fines and the results in the recovery of silicon was about 95% and it took place a refine of aluminium and calcium. (author)

  7. Influence of Microstructure on Thermal Properties of Axial Suspension Plasma-Sprayed YSZ Thermal Barrier Coatings

    Czech Academy of Sciences Publication Activity Database

    Ganvir, A.; Curry, N.; Markocsan, N.; Nylen, P.; Joshi, S.; Vilémová, Monika; Pala, Zdeněk

    2016-01-01

    Roč. 25, 1-2 (2016), s. 202-212 ISSN 1059-9630. [ITSC 2015: International Thermal Spray Conference and Exposition. Long Beach, California, 11.05.2015-14.05.2015] Institutional support: RVO:61389021 Keywords : axial injection * column ar microstructure * porosity * suspension plasma spraying * thermal conductivity * thermal diffusivity Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 1.488, year: 2016 http://link.springer.com/article/10.1007%2Fs11666-015-0355-7

  8. Plasma effects on subcellular structures

    International Nuclear Information System (INIS)

    Gweon, Bomi; Kim, Dan Bee; Jung, Heesoo; Choe, Wonho; Kim, Daeyeon; Shin, Jennifer H.

    2010-01-01

    Atmospheric pressure helium plasma treated human hepatocytes exhibit distinctive zones of necrotic and live cells separated by a void. We propose that plasma induced necrosis is attributed to plasma species such as oxygen radicals, charged particles, metastables and/or severe disruption of charged cytoskeletal proteins. Interestingly, uncharged cytoskeletal intermediate filaments are only minimally disturbed by plasma, elucidating the possibility of plasma induced electrostatic effects selectively destroying charged proteins. These bona fide plasma effects, which inflict alterations in specific subcellular structures leading to necrosis and cellular detachment, were not observed by application of helium flow or electric field alone.

  9. Final treatment of spent batteries by thermal plasma.

    Science.gov (United States)

    Cubas, Anelise Leal Vieira; Machado, Marina de Medeiros; Machado, Marília de Medeiros; Dutra, Ana Regina de Aguiar; Moecke, Elisa Helena Siegel; Fiedler, Haidi D; Bueno, Priscila

    2015-08-15

    The growth in the use of wireless devices, notebooks and other electronic products has led to an ever increasing demand for batteries, leading to these products being commonly found in inappropriate locations, with adverse effects on the environment and human health. Due to political pressure and according to the environmental legislation which regulates the destination of spent batteries, in several countries the application of reverse logistics to hazardous waste is required. Thus, some processes have been developed with the aim of providing an appropriate destination for these products. In this context, a method for the treatment of spent batteries using thermal plasma technology is proposed herein. The efficiency of the method was tested through the determination of parameters, such as total organic carbon, moisture content and density, as well as analysis by atomic absorption spectrometry, scanning electron microscopy and X-ray fluorescence using samples before and after inertization. The value obtained for the density was 19.15%. The TOC results indicated 8.05% of C in the batteries prior to pyrolisis and according to the XRF analysis Fe, S, Mn and Zn were the most stable elements in the samples (highest peaks). The efficiency of the paste inertization was 97% for zinc and 99.74% for manganese. The results also showed that the most efficient reactor was that with the DC transferred arc plasma torch and quartzite sand positively influenced by the vitrification during the pyrolysis of the electrolyte paste obtain from batteries. Copyright © 2015. Published by Elsevier Ltd.

  10. Optimal control theory applied to fusion plasma thermal stabilization

    International Nuclear Information System (INIS)

    Sager, G.; Miley, G.; Maya, I.

    1985-01-01

    Many authors have investigated stability characteristics and performance of various burn control schemes. The work presented here represents the first application of optimal control theory to the problem of fusion plasma thermal stabilization. The objectives of this initial investigation were to develop analysis methods, demonstrate tractability, and present some preliminary results of optimal control theory in burn control research

  11. Applying chemical engineering concepts to non-thermal plasma reactors

    Science.gov (United States)

    Pedro AFFONSO, NOBREGA; Alain, GAUNAND; Vandad, ROHANI; François, CAUNEAU; Laurent, FULCHERI

    2018-06-01

    Process scale-up remains a considerable challenge for environmental applications of non-thermal plasmas. Undersanding the impact of reactor hydrodynamics in the performance of the process is a key step to overcome this challenge. In this work, we apply chemical engineering concepts to analyse the impact that different non-thermal plasma reactor configurations and regimes, such as laminar or plug flow, may have on the reactor performance. We do this in the particular context of the removal of pollutants by non-thermal plasmas, for which a simplified model is available. We generalise this model to different reactor configurations and, under certain hypotheses, we show that a reactor in the laminar regime may have a behaviour significantly different from one in the plug flow regime, often assumed in the non-thermal plasma literature. On the other hand, we show that a packed-bed reactor behaves very similarly to one in the plug flow regime. Beyond those results, the reader will find in this work a quick introduction to chemical reaction engineering concepts.

  12. Treatment of mixed wastes by thermal plasma discharges

    International Nuclear Information System (INIS)

    Diaz A, L.V.

    2007-01-01

    The present study has as purpose to apply the technology of thermal plasma in the destruction of certain type of waste generated in the ININ. As first instance, origin, classification and disposition of the radioactive waste generated in the ININ is identified. Once identified the waste, the waste to treat is determined based on: the easiness of treating him with plasma, classification and importance. Later on, a substance or compound settles down (sample model) that serves as indicative of the waste for its physical-chemical characteristics, this is made because in the Thermal Plasma Applications Laboratory is not had the license to work with radioactive material. The sample model and the material to form the vitreous matrix are characterized before and after the treatment in order to evaluating their degradation and vitrification. During the treatment by means of the thermal plasma, the appropriate conditions are determined for the degradation and vitrification of the waste. Also, it is carried out an energy balance in the system to know the capacity to fuse the material depending the transfer of existent heat between the plasma and the material to treat. Obtaining favorable results, it thought about to climb in the project and by this way to help to solve one of the environmental problems in Mexico, as they are it the mixed wastes. (Author)

  13. Ion Streaming Instabilities in Pair Ion Plasma and Localized Structure with Non-Thermal Electrons

    Science.gov (United States)

    Nasir Khattak, M.; Mushtaq, A.; Qamar, A.

    2015-12-01

    Pair ion plasma with a fraction of non-thermal electrons is considered. We investigate the effects of the streaming motion of ions on linear and nonlinear properties of unmagnetized, collisionless plasma by using the fluid model. A dispersion relation is derived, and the growth rate of streaming instabilities with effect of streaming motion of ions and non-thermal electrons is calculated. A qausi-potential approach is adopted to study the characteristics of ion acoustic solitons. An energy integral equation involving Sagdeev potential is derived during this process. The presence of the streaming term in the energy integral equation affects the structure of the solitary waves significantly along with non-thermal electrons. Possible application of the work to the space and laboratory plasmas are highlighted.

  14. Ion streaming instabilities in pair ion plasma and localized structure with non-thermal electrons

    Energy Technology Data Exchange (ETDEWEB)

    Khattak, M. Nasir; Qamar, A., E-mail: mnnasirphysics@gmail.com [Department of Physics, University of Peshawar (Pakistan); Mushtaq, A. [Department of Physics, Abdul Wali Khan University Mardan, National Center for Physics, Mardan (Pakistan)

    2015-12-15

    Pair ion plasma with a fraction of non-thermal electrons is considered. We investigate the effects of the streaming motion of ions on linear and nonlinear properties of unmagnetized, collisionless plasma by using the fluid model. A dispersion relation is derived, and the growth rate of streaming instabilities with effect of streaming motion of ions and non-thermal electrons is calculated. A quasi-potential approach is adopted to study the characteristics of ion acoustic solitons. An energy integral equation involving Sagdeev potential is derived during this process. The presence of the streaming term in the energy integral equation affects the structure of the solitary waves significantly along with non-thermal electrons. Possible application of the work to the space and laboratory plasmas are highlighted. (author)

  15. Ion turbulence and thermal transport in laser-produced plasmas

    International Nuclear Information System (INIS)

    Barr, H.C.; Boyd, T.J.M.

    1982-01-01

    In the interaction of high-intensity lasers with target plasmas the transport of thermal energy from the region in which the radiation is absorbed, to the cold dense plasma in the interior of the target, is an issue of central importance. The role of ion turbulence as a flux limiter is addressed with particular regard to recent experiments in which target plasmas were irradiated by 1.06 μm neodymium laser light at irradiances of 10 15 W cm - 2 and greater. Saturation levels of the ion-acoustic turbulence driven by a combination of a suprathermal electron current and a heat flux are calculated on the basis of perturbed orbit theory. The levels of turbulence are found to be markedly lower than those commonly estimated from simple trapping arguments and too low to explain the thermal flux inhibition observed in the experiments used as a basis for the model. (author)

  16. Thermal plasma reduction of UF6

    International Nuclear Information System (INIS)

    Fincke, J.R.; Swank, W.D.; Haggard, D.C.

    1995-01-01

    This paper describes the experimental demonstration of a process for the direct plasma reduction of depleted uranium hexafluoride to uranium metal. The process exploits the large departures from equilibrium that can be achieved in the rapid supersonic expansion of a totally dissociated and partially ionized mixture of UF 6 , Ar, He, and H 2 . The process is based on the rapid condensation of subcooled uranium vapor and the relatively slow rate of back reaction between metallic uranium and HF to F 2 to reform stable fluorides. The high translational velocities and rapid cooling result in an overpopulation of atomic hydrogen which persists throughout the expansion process. Atomic hydrogen shifts the equilibrium composition by inhibiting the reformation of uranium-fluorine compounds. This process has the potential to reduce the cost of reducing UF 6 to uranium metal with the added benefit of being a virtually waste free process. The dry HF produced is a commodity which has industrial value

  17. Gravitational instability of thermally anisotropic plasma

    International Nuclear Information System (INIS)

    Singh, B.; Kalra, G.L.

    1986-01-01

    The equations of Chew, Goldberger, and Low (1956) modified to include the heat flux vector and self-gravitation are used to study the gravitational instability of unbounded plasma placed in a uniform static magnetic field. The linear stability analysis shows that some of the additional terms which arise as a result of higher moments are of the same order of magnitude as the terms in the original Chew, Goldberger, and Low theory. The influence of these terms on the gravitational instability has been specially examined. It is found that the gravitational instability sets in at a comparatively shorter wavelength and the growth rate is enhanced owing to the inclusion of these terms in the case where the propagation vector is along the magnetic field. The condition for instability is, however, unaltered when the direction of propagation is transverse to the direction of magnetic field. 19 references

  18. Thermal equilibrium criteria in a nitrogen plasma

    International Nuclear Information System (INIS)

    Cilliers, W.A.; Hey, J.D.; Rash, J.P.S.

    1975-01-01

    A method for obtaining the lower electron density limit for LTE in a nitrogen plasma is described, whereby the experimentally determined ratio of the collisional-radiative ionization and recombination coefficients (S/α) is compared with the corresponding LTE value (Saha ratio). It is argued that if the electron density is increased from values of about 10 16 cm -3 , S/α should tend to the Saha ratio as LTE is approached For NII and NIII spectral lines, this is found to happen at an electron density of a few times 10 16 cm -3 when the electron temperature is about 3 eV, in good agreement with the LTE criterion of Griem. (author)

  19. A dc non-thermal atmospheric-pressure plasma microjet

    Science.gov (United States)

    Zhu, WeiDong; Lopez, Jose L.

    2012-06-01

    A direct current (dc), non-thermal, atmospheric-pressure plasma microjet is generated with helium/oxygen gas mixture as working gas. The electrical property is characterized as a function of the oxygen concentration and show distinctive regions of operation. Side-on images of the jet were taken to analyze the mode of operation as well as the jet length. A self-pulsed mode is observed before the transition of the discharge to normal glow mode. Optical emission spectroscopy is employed from both end-on and side-on along the jet to analyze the reactive species generated in the plasma. Line emissions from atomic oxygen (at 777.4 nm) and helium (at 706.5 nm) were studied with respect to the oxygen volume percentage in the working gas, flow rate and discharge current. Optical emission intensities of Cu and OH are found to depend heavily on the oxygen concentration in the working gas. Ozone concentration measured in a semi-confined zone in front of the plasma jet is found to be from tens to ˜120 ppm. The results presented here demonstrate potential pathways for the adjustment and tuning of various plasma parameters such as reactive species selectivity and quantities or even ultraviolet emission intensities manipulation in an atmospheric-pressure non-thermal plasma source. The possibilities of fine tuning these plasma species allows for enhanced applications in health and medical related areas.

  20. A dc non-thermal atmospheric-pressure plasma microjet

    International Nuclear Information System (INIS)

    Zhu Weidong; Lopez, Jose L

    2012-01-01

    A direct current (dc), non-thermal, atmospheric-pressure plasma microjet is generated with helium/oxygen gas mixture as working gas. The electrical property is characterized as a function of the oxygen concentration and show distinctive regions of operation. Side-on images of the jet were taken to analyze the mode of operation as well as the jet length. A self-pulsed mode is observed before the transition of the discharge to normal glow mode. Optical emission spectroscopy is employed from both end-on and side-on along the jet to analyze the reactive species generated in the plasma. Line emissions from atomic oxygen (at 777.4 nm) and helium (at 706.5 nm) were studied with respect to the oxygen volume percentage in the working gas, flow rate and discharge current. Optical emission intensities of Cu and OH are found to depend heavily on the oxygen concentration in the working gas. Ozone concentration measured in a semi-confined zone in front of the plasma jet is found to be from tens to ∼120 ppm. The results presented here demonstrate potential pathways for the adjustment and tuning of various plasma parameters such as reactive species selectivity and quantities or even ultraviolet emission intensities manipulation in an atmospheric-pressure non-thermal plasma source. The possibilities of fine tuning these plasma species allows for enhanced applications in health and medical related areas. (paper)

  1. Functionalization of alkyne-terminated thermally hydrocarbonized porous silicon nanoparticles with targeting peptides and antifouling polymers: effect on the human plasma protein adsorption.

    Science.gov (United States)

    Wang, Chang-Fang; Mäkilä, Ermei M; Bonduelle, Colin; Rytkönen, Jussi; Raula, Janne; Almeida, Sérgio; Närvänen, Ale; Salonen, Jarno J; Lecommandoux, Sebastien; Hirvonen, Jouni T; Santos, Hélder A

    2015-01-28

    Porous silicon (PSi) nanomaterials combine a high drug loading capacity and tunable surface chemistry with various surface modifications to meet the requirements for biomedical applications. In this work, alkyne-terminated thermally hydrocarbonized porous silicon (THCPSi) nanoparticles were fabricated and postmodified using five bioactive molecules (targeting peptides and antifouling polymers) via a single-step click chemistry to modulate the bioactivity of the THCPSi nanoparticles, such as enhancing the cellular uptake and reducing the plasma protein association. The size of the nanoparticles after modification was increased from 176 to 180-220 nm. Dextran 40 kDa modified THCPSi nanoparticles showed the highest stability in aqueous buffer. Both peptide- and polymer-functionalized THCPSi nanoparticles showed an extensive cellular uptake which was dependent on the functionalized moieties presented on the surface of the nanoparticles. The plasma protein adsorption study showed that the surface modification with different peptides or polymers induced different protein association profiles. Dextran 40 kDa functionalized THCPSi nanoparticles presented the least protein association. Overall, these results demonstrate that the "click" conjugation of the biomolecules onto the alkyne-terminated THCPSi nanoparticles is a versatile and simple approach to modulate the surface chemistry, which has high potential for biomedical applications.

  2. Dynamic plasma screening effects on semiclassical inelastic electron endash ion collisions in dense plasmas

    International Nuclear Information System (INIS)

    Jung, Y.

    1997-01-01

    In dense plasmas, dynamic plasma screening effects are investigated on 1s→2p dipole transition probabilities for electron-impact excitation of hydrogenic ions. The electron endash ion interaction potential is considered by introduction of the plasma dielectric function. A semiclassical straight-line trajectory method is applied to the path of the projectile electron in order to visualize the semiclassical transition probability as a function of the impact parameter, projectile energy, and plasma parameters. The transition probability including the dynamic plasma screening effect is always greater than that including the static plasma screening effect. When the projectile velocity is smaller than the electron thermal velocity, the dynamic polarization screening effect becomes the static plasma screening effect. When the projectile velocity is greater than the electron thermal velocity, then the interaction potential is almost unshielded. The difference between the dynamic and static plasma screening effects is more significant for low-energy projectiles. It is also found that the static plasma screening formula obtained by the Debye endash Hueckel model overestimates the plasma screening effects on the atomic excitation processes in dense plasmas. copyright 1997 American Institute of Physics

  3. Powder processing and spheroidizing with thermal inductively coupled plasma

    International Nuclear Information System (INIS)

    Nutsch, G.; Linke, P.; Zakharian, S.; Dzur, B.; Weiss, K.-H.

    2001-01-01

    Processing of advanced powder materials for the spraying industry is one of the most promising applications of the thermal RF inductively coupled plasma. By selecting the feedstock carefully and adjusting the RF plasma parameters, unique materials with high quality can be achieved. Powders injected in the hot plasma core emerge with modified shapes, morphology, crystal structure and chemical composition. Ceramic oxide powders such as Al 2 O 3 , ZrO 2 , SiO 2 are spheroidized with a high spheroidization rate. By using the RF induction plasma spheroidizing process tungsten melt carbide powders are obtained with a high spheroidization rate at high feeding rates by densification of agglomerated powders consisting of di-tungsten carbide and monocarbide with a definite composition. This kind of ball-like powders is particularly suited for wear resistant applications. (author)

  4. Non-thermal dielectric barrier discharge plasma induces angiogenesis through reactive oxygen species.

    Science.gov (United States)

    Arjunan, Krishna Priya; Friedman, Gary; Fridman, Alexander; Clyne, Alisa Morss

    2012-01-07

    Vascularization plays a key role in processes such as wound healing and tissue engineering. Non-thermal plasma, which primarily produces reactive oxygen species (ROS), has recently emerged as an efficient tool in medical applications including blood coagulation, sterilization and malignant cell apoptosis. Liquids and porcine aortic endothelial cells were treated with a non-thermal dielectric barrier discharge plasma in vitro. Plasma treatment of phosphate-buffered saline (PBS) and serum-free medium increased ROS concentration in a dose-dependent manner, with a higher concentration observed in serum-free medium compared with PBS. Species concentration inside cells peaked 1 h after treatment, followed by a decrease 3 h post treatment. Endothelial cells treated with a plasma dose of 4.2 J cm(-2) had 1.7 times more cells than untreated samples 5 days after plasma treatment. The 4.2 J cm(-2) plasma dose increased two-dimensional migration distance by 40 per cent compared with untreated control, while the number of cells that migrated through a three-dimensional collagen gel increased by 15 per cent. Tube formation was also enhanced by plasma treatment, with tube lengths in plasma-treated samples measuring 2.6 times longer than control samples. A fibroblast growth factor-2 (FGF-2) neutralizing antibody and ROS scavengers abrogated these angiogenic effects. These data indicate that plasma enhanced proliferation, migration and tube formation is due to FGF-2 release induced by plasma-produced ROS. Non-thermal plasma may be used as a potential tool for applying ROS in precise doses to enhance vascularization.

  5. Inductive thermal plasma generation applied for the materials coating

    International Nuclear Information System (INIS)

    Pacheco, J.; Pena, R.; Cota, G.; Segovia, A.; Cruz, A.

    1996-01-01

    The coatings by thermal plasma are carried out introducing particles into a plasma system where they are accelerated and melted (total or partially) before striking the substrate to which they adhere and are suddenly cooled down. The nature of consolidation and solidification of the particles allows to have control upon the microstructure of the deposit. This technique is able to deposit any kind of material that is suitable to be merged (metal, alloy, ceramic, glass) upon any type of substrate (metal, graphite, ceramic, wood) with an adjustable thickness ranging from a few microns up to several millimeters. The applications are particularly focused to the coating of materials in order to improve their properties of resistance to corrosion, thermal and mechanical efforts as well as to preserve the properties of the so formed compound. In this work the electromagnetic induction phenomenon in an ionized medium by means of electric conductivity, is described. Emphasis is made on the devices and control systems employed in order to generate the thermal plasma and in carrying out the coatings of surfaces by the projection of particles based on plasma

  6. Thermal cycling characteristics of plasma synthesized mullite films

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, O.R.; Hou, P.Y.; Brown, I.G. [Lawrence Berkeley National Lab., CA (United States)

    1997-12-01

    The authors have developed a plasma-based technique for the synthesis of mullite and mullite-like films on silicon carbide substrate material. The method, which they refer to as MePIIID (for Metal Plasma Immersion Ion Implantation and Deposition), uses two vacuum arc plasma sources and simultaneous pulse biasing of the substrate in a low pressure oxygen atmosphere. The Al:Si ratio can be controlled via the separate plasma guns, and the film adhesion, structure and morphology can be controlled via the ion energy which in turn is controlled by the pulse bias voltage. The films are amorphous as-deposited, and crystalline mullite is formed by subsequent annealing at 1000 C for 2 hours in air. Adhesion between the aluminum-silicon oxide film and the substrate increases after this first annealing. They have tested the behavior of films when subjected to repetitive thermal cycling between room temperature and 1100 C, and found that the films retain their adhesion and quality. Here they review the plasma synthesis technique and the characteristics of the mullite films prepared in this way, and summarize the status of the thermal cycling experiments.

  7. Thermal consequences of plasma disruptions in TFTR and ETF

    International Nuclear Information System (INIS)

    Budny, R.; Ludescher, C.

    1981-01-01

    We studied thermal responses of first walls for TFTR and ETF during plasma disruptions. To model the flux, we assumed the entire kinetic energy is deposited by axisymmetric horizontal displacement of the plasma. The deposition time is a free parameter. In TFTR, the minimum deposition time which does not cause the toroidal limiter to melt is 7 or 14 ms depending on whether or not the limiter is actively cooled. In ETF, the minimum time which does not cause surface melting of the cooling tubes is 80 ms. (author)

  8. Non-thermal plasma mills bacteria: scanning electron microscopy observations

    Czech Academy of Sciences Publication Activity Database

    Lunov, Oleg; Churpita, Olexandr; Zablotskyy, Vitaliy A.; Deyneka, I.G.; Meshkovskii, I.K.; Jäger, Aleš; Syková, Eva; Kubinová, Šárka; Dejneka, Alexandr

    2015-01-01

    Roč. 106, č. 5 (2015), "053703-1"-"053703-5" ISSN 0003-6951 R&D Projects: GA MŠk(CZ) LM2011029; GA MŠk(CZ) LM2011026; GA MŠk LO1309 Grant - others:AV ČR(CZ) M100101219; SAFMAT(XE) CZ.2.16/3.1.00/22132 Institutional support: RVO:68378271 ; RVO:68378041 Keywords : non-thermal plasma * plasma medicine * bacteria * cells Subject RIV: BO - Biophysics Impact factor: 3.142, year: 2015

  9. Experimental studies on removal of airborne haloanisoles by non-thermal plasma air purifiers

    DEFF Research Database (Denmark)

    Fang, Lei; Hallam, David; Bermúdez, Raúl

    2016-01-01

    A laboratory study was conducted to test the performance of non-thermal plasma air purifiers on its removal effectiveness of two haloanisoles – 2,4,6-trichloroanisole (TCA) and 2,4,6-Tribromoanisole (TBA). TCA and TBA are the two major compounds found in wine cellars that can contaminate wine to ...

  10. Antimicrobial properties of uncapped silver nanoparticles synthesized by DC arc thermal plasma technique.

    Science.gov (United States)

    Shinde, Manish; Patil, Rajendra; Karmakar, Soumen; Bhoraskar, Sudha; Rane, Sunit; Gade, Wasudev; Amalnerkar, Dinesh

    2012-02-01

    We, herein, report the antimicrobial properties of uncapped silver nanoparticles for a Gram positive model organism, Bacillus subtilis. Uncapped silver nanoparticles have been prepared using less-explored DC arc thermal plasma technique by considering its large scale generation capability. It is observed that the resultant nanoparticles show size as well as optical property dependent antimicrobial effect.

  11. Plasma thermal conversion of bio-oil for hydrogen production

    International Nuclear Information System (INIS)

    Guenadou, David; Lorcet, Helene; Peybernes, Jean; Catoire, Laurent; Osmont, Antoine; Gokalp, Iskender

    2012-01-01

    Numerous processes exist or are proposed for the energetic conversion of biomass. The use of thermal plasma is proposed in the frame of the GALACSY project for the conversion of bio-oil to hydrogen and carbon monoxide. For this purpose, an experimental apparatus has been built. The feasibility of this conversion at very high temperature, as encountered in thermal plasma, is examined both experimentally and numerically. This zero dimensional study tends to show that a high temperature (around 2500 K or above) is needed to ensure a high yield of hydrogen (about 50 mol%) and about 95 mol% of CO+H 2 . Predicted CO+H 2 yield and CO/H 2 ratio are consistent with measurements. It is also expected that the formation of particles and tars is hampered. Thermodynamic data of selected bio-oil components are provided in the CHEMKINNASA format. (authors)

  12. Relativistic self-focusing of intense laser beam in thermal collisionless quantum plasma with ramped density profile

    Directory of Open Access Journals (Sweden)

    S. Zare

    2015-04-01

    Full Text Available Propagation of a Gaussian x-ray laser beam has been analyzed in collisionless thermal quantum plasma with considering a ramped density profile. In this density profile due to the increase in the plasma density, an earlier and stronger self-focusing effect is noticed where the beam width oscillates with higher frequency and less amplitude. Moreover, the effect of the density profile slope and the initial plasma density on the laser propagation has been studied. It is found that, by increasing the initial density and the ramp slope, the laser beam focuses faster with less oscillation amplitude, smaller laser spot size and more oscillations. Furthermore, a comparison is made among the laser self-focusing in thermal quantum plasma, cold quantum plasma and classical plasma. It is realized that the laser self-focusing in the quantum plasma becomes stronger in comparison with the classical regime.

  13. Pre-treating water with non-thermal plasma

    Science.gov (United States)

    Cho, Young I.; Fridman, Alexander; Rabinovich, Alexander; Cho, Daniel J.

    2017-07-04

    The present invention consists of a method of pre-treatment of adulterated water for distillation, including adulterated water produced during hydraulic fracturing ("fracking") of shale rock during natural gas drilling. In particular, the invention is directed to a method of treating adulterated water, said adulterated water having an initial level of bicarbonate ion in a range of about 250 ppm to about 5000 ppm and an initial level of calcium ion in a range of about 500 ppm to about 50,000 ppm, said method comprising contacting the adulterated water with a non-thermal arc discharge plasma to produce plasma treated water having a level of bicarbonate ion of less than about 100 ppm. Optionally, the plasma treated water may be further distilled.

  14. Application of non-thermal plasmas to pollution control

    International Nuclear Information System (INIS)

    Penetrante, B.M.; Vogtlin, G.E.; Bardsley, J.N.; Vitello, P.A.; Wallman, P.H.

    1993-06-01

    Non-thermal plasma techniques can be used to destroy many types of hazardous molecules. They are particularly efficient when the toxic materials are present in very small concentrations. This paper discusses three particular applications of non-thermal plasmas: (1) decomposition of hydrogen sulfide (H 2 S), (2) removal of trichloroethylene (TCE), and (3) removal of nitrogen oxides (NO x ). Emphasis is placed on the energy cost for implementing the decomposition or removal of these pollutants. Some of the factors affecting the energy cost are discussed. The authors discuss in detail their work at LLNL on pulsed plasma processing for the treatment of NO x in diesel engine exhaust. The results suggest that their plasma reactor can remove up to 70% of NO with relatively high initial concentrations (up to 500 ppM) at a power consumption cost of 2.5% for an engine with an output of 14 kW and an exhaust gas flow rate of 1,200 liters per minute

  15. Application of non-thermal plasmas to pollution control

    International Nuclear Information System (INIS)

    Penetrante, B.M.; Vogtlin, G.E.; Bardsley, J.N.; Vitello, P.A.; Wallman, P.H.

    1993-01-01

    Non-thermal plasma techniques can be used to destroy many types of hazardous molecules. They are particularly efficient when the toxic materials are present in very small concentrations. This paper discusses three particular applications of non-thermal plasmas: (1) decomposition of hydrogen sulfide (H 2 S), (2) removal of trichloroethylene (TCE), and (3) removal of nitric oxides (NO x ) Emphasis is placed on the energy cost for implementing the decomposition or removal of these pollutants. Some of the factors affecting the energy cost are discussed. We discuss in detail our work at LLNL on pulsed plasma processing for the treatment of NO x in diesel engine exhaust. Our results suggest that our plasma reactor can remove up to 70% of NO x with relatively high initial concentrations (up to 500 ppM) at a power consumption cost of 2.5% for an engine with an output of 14 kill and an exhaust gas flow rate of 1200 liters per minute

  16. Effects of thermal annealing on the structural, mechanical, and tribological properties of hard fluorinated carbon films deposited by plasma enhanced chemical vapor deposition

    Science.gov (United States)

    Maia da Costa, M. E. H.; Baumvol, I. J. R.; Radke, C.; Jacobsohn, L. G.; Zamora, R. R. M.; Freire, F. L.

    2004-11-01

    Hard amorphous fluorinated carbon films (a-C:F) deposited by plasma enhanced chemical vapor deposition were annealed in vacuum for 30 min in the temperature range of 200-600 °C. The structural and compositional modifications were followed by several analytical techniques: Rutherford backscattering spectrometry (RBS), elastic recoil detection analysis (ERDA), x-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Nanoidentation measurements and lateral force microscopy experiments were carried out in order to provide the film hardness and the friction coefficient, respectively. The internal stress and contact angle were also measured. RBS, ERDA, and XPS results indicate that both fluorine and hydrogen losses occur for annealing temperatures higher than 300 °C. Raman spectroscopy shows a progressive graphitization upon annealing, while the surface became slightly more hydrophobic as revealed by the increase of the contact angle. Following the surface wettability reduction, a decrease of the friction coefficient was observed. These results highlight the influence of the capillary condensation on the nanoscale friction. The film hardness and the internal stress are constant up to 300 °C and decrease for higher annealing temperatures, showing a direct correlation with the atomic density of the films. Since the thickness variation is negligible, the mass loss upon thermal treatment results in amorphous structures with a lower degree of cross-linking, explaining the deterioration of the mechanical properties of the a-C:F films.

  17. Porous materials produced from incineration ash using thermal plasma technology.

    Science.gov (United States)

    Yang, Sheng-Fu; Chiu, Wen-Tung; Wang, To-Mai; Chen, Ching-Ting; Tzeng, Chin-Ching

    2014-06-01

    This study presents a novel thermal plasma melting technique for neutralizing and recycling municipal solid waste incinerator (MSWI) ash residues. MSWI ash residues were converted into water-quenched vitrified slag using plasma vitrification, which is environmentally benign. Slag is adopted as a raw material in producing porous materials for architectural and decorative applications, eliminating the problem of its disposal. Porous materials are produced using water-quenched vitrified slag with Portland cement and foaming agent. The true density, bulk density, porosity and water absorption ratio of the foamed specimens are studied here by varying the size of the slag particles, the water-to-solid ratio, and the ratio of the weights of the core materials, including the water-quenched vitrified slag and cement. The thermal conductivity and flexural strength of porous panels are also determined. The experimental results show the bulk density and the porosity of the porous materials are 0.9-1.2 g cm(-3) and 50-60%, respectively, and the pore structure has a closed form. The thermal conductivity of the porous material is 0.1946 W m(-1) K(-1). Therefore, the slag composite materials are lightweight and thermal insulators having considerable potential for building applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Nonthermal and screening effects on photoionizations in Lorentzian plasmas

    International Nuclear Information System (INIS)

    Shin, Dong-Soo; Jung, Young-Dae

    2009-01-01

    The nonthermal and plasma screening effects on the x-ray photoionization process are investigated in astrophysical Lorentzian plasmas. The screened atomic wave function and energy eigenvalue of the target ion in Lorentzian plasmas are obtained by the Rayleigh-Ritz variational method. The x-ray retardation and screened Coulomb corrections are considered to obtain a photoionization cross section as a function of the spectral index and plasma parameters. It is shown that the nonthermal character of the Lorentzian plasma suppresses the photoionization cross section. Hence, the photoionization cross sections in nonthermal plasmas are found to be always smaller than those in thermal plasmas. It is also shown that the plasma screening effect is more significant for small spectral indices. In addition, the nonthermal effect on the photoionization cross section is found to be decreased with an increase in the Debye length.

  19. Analysis of the expanding thermal argon-oxygen plasma gas phase

    International Nuclear Information System (INIS)

    Hest, M F A M van; Haartsen, J R; Weert, M H M van; Schram, D C; Sanden, M C M van de

    2003-01-01

    An expanding thermal argon plasma into which oxygen is injected has been analysed by means of Langmuir and Pitot probe measurements. Information is obtained on the ion density profile and the flow pattern in the downstream plasma. A combination of Langmuir and Pitot probe measurements provide information on the total ion flux generated by the plasma source (cascaded arc). It has been found that the ion diffusion is mainly determined by the background pressure in the expansion vessel and the arc current. The ion density is determined by the total power input into the plasma as well as the gas flow in the plasma source. There is an optimum in the power transfer used for ionization from plasma source to the feed gas. Interaction of oxygen with the plasma results in a decrease in the argon ion density and the plasma beam radius. The recirculation pattern of the downstream plasma has been investigated experimentally using the Pitot probe. Due to the low downstream pressure (10-30 Pa), the conventional compressible Pitot probe theory no longer applies. It is concluded that viscous effects start to play an important role at these low pressures and should be taken into account in the analysis of the Pitot probe measurements

  20. Thermal effects of divertor sweeping in ITER

    International Nuclear Information System (INIS)

    Wesley, J.C.

    1992-01-01

    In this paper, thermal effects of magnetically sweeping the separatrix strike point on the outer divertor target of the International Thermonuclear Fusion Reactor (ITER) are calculated. For the 0. 2 Hz x ± 12 cm sweep scenario proposed for ITER operations, the thermal capability of a generic target design is found to be slightly inadequate (by ∼ 5%) to accommodate the full degree of plasma scrape-off peaking postulated as a design basis. The principal problem identified is that the 5 s sweep period is long relative to the 1. 4 s thermal time constant of the divertor target. An increase of the sweep frequency to ∼ 1 Hz is suggested: this increase would provide a power handling margin of ∼ 25% relative to present operational criteria

  1. Non-thermal plasma instabilities induced by deformation of the electron energy distribution function

    Science.gov (United States)

    Dyatko, N. A.; Kochetov, I. V.; Napartovich, A. P.

    2014-08-01

    Non-thermal plasma is a key component in gas lasers, microelectronics, medical applications, waste gas cleaners, ozone generators, plasma igniters, flame holders, flow control in high-speed aerodynamics and others. A specific feature of non-thermal plasma is its high sensitivity to variations in governing parameters (gas composition, pressure, pulse duration, E/N parameter). This sensitivity is due to complex deformations of the electron energy distribution function (EEDF) shape induced by variations in electric field strength, electron and ion number densities and gas excitation degree. Particular attention in this article is paid to mechanisms of instabilities based on non-linearity of plasma properties for specific conditions: gas composition, steady-state and decaying plasma produced by the electron beam, or by an electric current pulse. The following effects are analyzed: the negative differential electron conductivity; the absolute negative electron mobility; the stepwise changes of plasma properties induced by the EEDF bi-stability; thermo-current instability and the constriction of the glow discharge column in rare gases. Some of these effects were observed experimentally and some of them were theoretically predicted and still wait for experimental confirmation.

  2. Operational features and air plasma characteristics of a thermal plasma torch with hollow electrodes

    International Nuclear Information System (INIS)

    Hur, Min; Kim, Keun Su; Hong, Sang Hee

    2003-01-01

    The operational features and thermal plasma characteristics of a plasma torch with hollow electrodes are investigated based on their dependence on input current, gas flow rate and electrode diameter when air is used as a plasma gas. A plasma torch with a hollow cathode and anode has been designed and fabricated, and the arc voltages and thermal efficiencies are measured from its discharge. The newly modified similarity criteria are derived from the measured data related to torch performances. From the fact that these criteria successfully describe both the arc voltage and thermal efficiency behaviour of the torch, depending on its operating and geometrical parameters, it is proved that they can be usefully applied to the design and operation of high power torches. For the numerical modelling of the interior region of the torch, a cold flow analysis is employed along with a simplified balance equation of the Lorentz and gas dynamic drag forces in order to determine a cathode spot position on the cathode surface. The validity of this method is confirmed by comparison of the calculated and measured net powers. As a practically useful result of this analysis, carried out through this numerical and experimental work, it is suggested that low input current, high gas flow rate and relatively large electrode diameter are more favourable as appropriate operating conditions of the torch for the efficient treatment of hazardous organic wastes

  3. Time-resolved probing of electron thermal conduction in femtosecond-laser-pulse-produced plasmas

    International Nuclear Information System (INIS)

    Vue, B.T.V.

    1993-06-01

    We present time-resolved measurements of reflectivity, transmissivity and frequency shifts of probe light interacting with the rear of a disk-like plasma produced by irradiation of a transparent solid target with 0.1ps FWHM laser pulses at peak intensity 5 x 10 l4 W/CM 2 . Experimental results show a large increase in reflection, revealing rapid formation of a steep gradient and overdense surface plasma layer during the first picosecond after irradiation. Frequency shifts due to a moving ionization created by thermal conduction into the solid target are recorded. Calculations using a nonlinear thermal heat wave model show good agreement with the measured frequency shifts, further confining the strong thermal transport effect

  4. Skin effect of microwaves and transverse pseudowaves in plasmas

    International Nuclear Information System (INIS)

    Minami, Kazuo

    1977-09-01

    Using linearized Vlasov-Maxwell equations, the skin effect of microwaves and transverse pseudowaves excited by an idealized grid antenna in plasmas are analyzed. It is shown that the latter is predominant over the former, in such a plasma that ω sub(p) v sub(t)/ωc >= 1, where ω sub(p) and ω are the plasma and microwave angular frequencies, v sub(t) and c are the electron thermal and light velocities, respectively. (auth.)

  5. Low temperature synthesis of silicon quantum dots with plasma chemistry control in dual frequency non-thermal plasmas.

    Science.gov (United States)

    Sahu, Bibhuti Bhusan; Yin, Yongyi; Han, Jeon Geon; Shiratani, Masaharu

    2016-06-21

    The advanced materials process by non-thermal plasmas with a high plasma density allows the synthesis of small-to-big sized Si quantum dots by combining low-temperature deposition with superior crystalline quality in the background of an amorphous hydrogenated silicon nitride matrix. Here, we make quantum dot thin films in a reactive mixture of ammonia/silane/hydrogen utilizing dual-frequency capacitively coupled plasmas with high atomic hydrogen and nitrogen radical densities. Systematic data analysis using different film and plasma characterization tools reveals that the quantum dots with different sizes exhibit size dependent film properties, which are sensitively dependent on plasma characteristics. These films exhibit intense photoluminescence in the visible range with violet to orange colors and with narrow to broad widths (∼0.3-0.9 eV). The observed luminescence behavior can come from the quantum confinement effect, quasi-direct band-to-band recombination, and variation of atomic hydrogen and nitrogen radicals in the film growth network. The high luminescence yields in the visible range of the spectrum and size-tunable low-temperature synthesis with plasma and radical control make these quantum dot films good candidates for light emitting applications.

  6. Heavy metals behavior during thermal plasma vitrification of incineration residues

    International Nuclear Information System (INIS)

    Cerqueira, N.; Vandensteendam, C.; Baronnet, J.M.

    2005-01-01

    In the developed world, incineration of wastes is widely and increasingly practiced. Worldwide, a total of approximately 100 millions of tons of municipal solid waste (MSW) material is incinerated annually. Incineration of one ton of MSW leads to the formation of 30 to 50 kg of fly ash, depending on the type of incinerator. The waste disposal of these dusts already causes great problems today; they are of low bulk density, they contain high concentrations of hazardous water-soluble heavy metal compounds, organohalogen compounds (dioxines, furanes), sulfur, and chlorinated compounds. Thermal processes, based mainly on electrical arc processes, show great promise: the residues are melted at high temperature and converted in a relatively inert glass. A few tens of plants, essentially in Japan and Taiwan, have been in industrial operation for a few years. To be authorized to be dumped in a common landfill, the glassy product has to satisfy the leaching test procedure to ensure long-term durability. But to satisfy the regulation to be reused, for example as a nonhazardous standard material in road building, the glassy product would probably include contents in some heavy metals lower than critical limits. So today, there are two alternatives: the first one is to improve the heavy toxic metals evaporation to get a 'light' glassy product and to recycle separately the said separated metals; the second is on the contrary to improve the incorporation of a maximum of heavy metals into the vitreous silicate matrix. Whatever, it is highly required to control, in situ and in real time, volatility of these metals during ash melting under electrical arc. The objective of this work was to reach basic data about metals volatility under the plasma column of an electrical arc transferred on the melt: an experiment has been designed to examine the effects of processing conditions, such as melt temperature, melt composition, and furnace atmosphere, upon volatilization and glassy slag

  7. Thermal effects in supercapacitors

    CERN Document Server

    Xiong, Guoping; Fisher, Timothy S

    2015-01-01

    This Brief reviews contemporary research conducted in university and industry laboratories on thermal management in electrochemical energy storage systems (capacitors and batteries) that have been widely used as power sources in many practical applications, such as automobiles, hybrid transport, renewable energy installations, power backup and electronic devices. Placing a particular emphasis on supercapacitors, the authors discuss how supercapacitors, or ultra capacitors, are complementing and  replacing, batteries because of their faster power delivery, longer life cycle and higher coulombic efficiency, while providing higher energy density than conventional electrolytic capacitors. Recent advances in both macro- and micro capacitor technologies are covered. The work facilitates systematic understanding of thermal transport in such devices that can help develop better power management systems.

  8. Enhanced active aluminum content and thermal behaviour of nano-aluminum particles passivated during synthesis using thermal plasma route

    International Nuclear Information System (INIS)

    Mathe, Vikas L.; Varma, Vijay; Raut, Suyog; Nandi, Amiya Kumar; Pant, Arti; Prasanth, Hima; Pandey, R.K.; Bhoraskar, Sudha V.; Das, Asoka K.

    2016-01-01

    Graphical abstract: - Highlights: • Synthesis of nano crystalline Al (nAl) using DC thermal plasma reactor. • In situ passivation of nAl by palmitic acid and air. • Enhanced active aluminum content obtained for palmitic acid passivated nAl. • Palmitic acid passivated nAl are quite stable in humid atmospheres. - Abstract: Here, we report synthesis and in situ passivation of aluminum nanoparticles using thermal plasma reactor. Both air and palmitc acid passivation was carried out during the synthesis in the thermal plasma reactor. The passivated nanoparticles have been characterized for their structural and morphological properties using X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. In order to understand nature of passivation vibrational spectroscopic analysis have been carried out. The enhancement in active aluminum content and shelf life for a palmitic acid passivated nano-aluminum particles in comparison to the air passivated samples and commercially available nano Al powder (ALEX) has been observed. Thermo-gravimetric analysis was used to estimate active aluminum content of all the samples under investigation. In addition cerimetric back titration method was also used to estimate AAC and the shelf life of passivated aluminum particles. Structural, microstructural and thermogravomateric analysis of four year aged passivated sample also depicts effectiveness of palmitic acid passivation.

  9. Enhanced active aluminum content and thermal behaviour of nano-aluminum particles passivated during synthesis using thermal plasma route

    Energy Technology Data Exchange (ETDEWEB)

    Mathe, Vikas L., E-mail: vlmathe@physics.unipune.ac.in [Department of Physics, Savitribai Phule Pune University, Pune 411007, Maharashtra (India); Varma, Vijay; Raut, Suyog [Department of Physics, Savitribai Phule Pune University, Pune 411007, Maharashtra (India); Nandi, Amiya Kumar; Pant, Arti; Prasanth, Hima; Pandey, R.K. [High Energy Materials Research Lab, Sutarwadi, Pune 411021, Maharashtra (India); Bhoraskar, Sudha V. [Department of Physics, Savitribai Phule Pune University, Pune 411007, Maharashtra (India); Das, Asoka K. [Utkal University, VaniVihar, Bhubaneswar, Odisha 751004 (India)

    2016-04-15

    Graphical abstract: - Highlights: • Synthesis of nano crystalline Al (nAl) using DC thermal plasma reactor. • In situ passivation of nAl by palmitic acid and air. • Enhanced active aluminum content obtained for palmitic acid passivated nAl. • Palmitic acid passivated nAl are quite stable in humid atmospheres. - Abstract: Here, we report synthesis and in situ passivation of aluminum nanoparticles using thermal plasma reactor. Both air and palmitc acid passivation was carried out during the synthesis in the thermal plasma reactor. The passivated nanoparticles have been characterized for their structural and morphological properties using X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. In order to understand nature of passivation vibrational spectroscopic analysis have been carried out. The enhancement in active aluminum content and shelf life for a palmitic acid passivated nano-aluminum particles in comparison to the air passivated samples and commercially available nano Al powder (ALEX) has been observed. Thermo-gravimetric analysis was used to estimate active aluminum content of all the samples under investigation. In addition cerimetric back titration method was also used to estimate AAC and the shelf life of passivated aluminum particles. Structural, microstructural and thermogravomateric analysis of four year aged passivated sample also depicts effectiveness of palmitic acid passivation.

  10. Thermal Conductivity Analysis and Lifetime Testing of Suspension Plasma-Sprayed Thermal Barrier Coatings

    Directory of Open Access Journals (Sweden)

    Nicholas Curry

    2014-08-01

    Full Text Available Suspension plasma spraying (SPS has become an interesting method for the production of thermal barrier coatings for gas turbine components. The development of the SPS process has led to structures with segmented vertical cracks or column-like structures that can imitate strain-tolerant air plasma spraying (APS or electron beam physical vapor deposition (EB-PVD coatings. Additionally, SPS coatings can have lower thermal conductivity than EB-PVD coatings, while also being easier to produce. The combination of similar or improved properties with a potential for lower production costs makes SPS of great interest to the gas turbine industry. This study compares a number of SPS thermal barrier coatings (TBCs with vertical cracks or column-like structures with the reference of segmented APS coatings. The primary focus has been on lifetime testing of these new coating systems. Samples were tested in thermo-cyclic fatigue at temperatures of 1100 °C for 1 h cycles. Additional testing was performed to assess thermal shock performance and erosion resistance. Thermal conductivity was also assessed for samples in their as-sprayed state, and the microstructures were investigated using SEM.

  11. Surface modification of biphasic calcium phosphate scaffolds by non-thermal atmospheric pressure nitrogen and air plasma treatment for improving osteoblast attachment and proliferation

    International Nuclear Information System (INIS)

    Choi, Yu-Ri; Kwon, Jae-Sung; Song, Doo-Hoon; Choi, Eun Ha; Lee, Yong-Keun; Kim, Kyoung-Nam; Kim, Kwang-Mahn

    2013-01-01

    Surface modifications induced by non-thermal plasma have been used extensively in biomedical applications. The attachment and proliferation of osteoblast cells are important in bone tissue engineering using scaffolds. Hence the effect of non-thermal plasma on hydroxyapatite/β-tri-calcium phosphate (HA/β-TCP) scaffolds in terms of improving osteoblast attachment and proliferation was investigated. Experimental groups were treated with non-thermal plasma for 10 min and 20 min and a control group was not treated with non-thermal plasma. For surface chemistry analysis, X-ray photoelectron spectroscopy (XPS) analysis was carried out. The hydrophilicity was determined from contact angle measurement on the surface. Atomic force microscopy analysis (AFM) was used to test the change in surface roughness and cell attachment and proliferation were evaluated using MC3T3-E1 osteoblast cells. XPS spectra revealed a decreased amount of carbon on the surface of the plasma-treated sample. The contact angle was also decreased following plasma treatment, indicating improved hydrophilicity of plasma-treated surfaces compared to the untreated disc. A significant increase in MC3T3E-1 cell attachment and proliferation was noted on plasma-treated samples as compared to untreated specimens. The results suggest that non-thermal atmospheric pressure nitrogen and air plasma treatments provide beneficial surface characteristics on HA/β-TCP scaffolds. - Highlights: ► Non-thermal plasma increased OH- and decreased C on biphasic scaffold. ► Non-thermal plasma had no effect on surface roughness. ► Non-thermal plasma resulted in hydrophilic surface. ► Non-thermal plasma resulted in better cell attachment and proliferation. ► Non-thermal plasma treatment on biphasic scaffold is useful for tissue engineering

  12. Radial thermal diffusivity of toroidal plasma affected by resonant magnetic perturbations

    International Nuclear Information System (INIS)

    Kanno, Ryutaro; Nunami, Masanori; Satake, Shinsuke; Takamaru, Hisanori; Okamoto, Masao

    2012-04-01

    We investigate how the radial thermal diffusivity of an axisymmetric toroidal plasma is modified by effect of resonant magnetic perturbations (RMPs), using a drift kinetic simulation code for calculating the thermal diffusivity in the perturbed region. The perturbed region is assumed to be generated on and around the resonance surfaces, and is wedged in between the regular closed magnetic surfaces. It has been found that the radial thermal diffusivity χ r in the perturbed region is represented as χ r = χ r (0) {1 + c r parallel 2 >}. Here r parallel 2 > 1/2 is the strength of the RMPs in the radial directions, means the flux surface average defined by the unperturbed (i.e., original) magnetic field, χ r (0) is the neoclassical thermal diffusivity, and c is a positive coefficient. In this paper, dependence of the coefficient c on parameters of the toroidal plasma is studied in results given by the δ f simulation code solving the drift kinetic equation under an assumption of zero electric field. We find that the dependence of c is given as c ∝ ω b /ν eff m in the low collisionality regime ν eff b , where ν eff is the effective collision frequency, ω b is the bounce frequency and m is the particle mass. In case of ν eff > ω b , the thermal diffusivity χ r evaluated by the simulations becomes close to the neoclassical thermal diffusivity χ r (0) . (author)

  13. HNS steelmaking process using thermal plasma in a ceramic crucible

    International Nuclear Information System (INIS)

    Siwka, J.; Svyazhin, A.G.; Jowsa, J.; Derda, W.

    1999-01-01

    The problems related to HNS (high nitrogen steels) steelmaking technology in a laboratory plasma furnace (100 kW DC, 25 kg liquid metal) are discussed in the paper. Results of investigations on mass transfer in the bath, modelling of the temperature fields by the FEM method, the dynamics of nitriding and refining of the liquid metal are presented. The results show many advantageous features of this technology and identify the necessary modifications. Realization of the one-stage production process of HNS is possible using thermal plasma. This means that any kind of metallic scrap can be used with simultaneous nitriding of liquid metal by nitrogen gas phase and its refining. A technological scheme of the discussed process is presented. (orig.)

  14. Development of twin cannons of thermal plasma; Desarrollo de canones gemelos de plasma termico.

    Energy Technology Data Exchange (ETDEWEB)

    Pena E, R [Instituto Nacional de Investigaciones Nucleares, Mexico D.F. (Mexico)

    1997-12-31

    Today several service and transformation industries that generate hazardous wastes must implement programs in order to fulfill with requirements established by the present standardization. This problem is solved here for proposing the design and construction of a thermal plasma transferred torch with double cannon which is generated by an electric arc with a capacity of 50 k W, a regulable gas flow from 0-50 lt./min and thermal yield higher than 85 %. This equipment would be capable for degradating industrial and hospital wastes. (Author).

  15. Thermal Plasma Decomposition Of Nickel And Cobalt Compounds

    Directory of Open Access Journals (Sweden)

    Woch M.

    2015-06-01

    Full Text Available The paper presents the study on manufacturing of nickel and cobalt powders by thermal plasma decomposition of the carbonates of these metals. It was shown the dependence of process parameters and grain size of initial powder on the composition of final product which was ether metal powder, collected in the container as well as the nanopowder with crystallite size of 70 - 90 nm, collected on the inner wall of the reaction chamber. The occurrence of metal oxides in the final products was confirmed and discussed.

  16. Two phases of droplet evaporation during plasma arc spraying: reply to Chen's comment about the 'rocket' effect under conditions of thermal plasma spraying

    Energy Technology Data Exchange (ETDEWEB)

    Nemchinsky, V A [Key College, 225 Dania Beach Blvd, Dania Beach, FL 33040 (United States)

    2007-07-07

    The heating history of a droplet during its flight can be divided into two phases: (a) the initial phase when evaporation, although it occurs, does not change the heat balance of the droplet much (the case considered in our previous paper and (b) the final phase when the cooling due to evaporation balances the heat flux from the plasma. The later phase is considered in Chen's comment. In our reply, a very straightforward consideration demonstrates that even in the final phase of the droplet flight, the 'rocket' effect can be significant. (reply)

  17. Plasma spheroidization of iron powders in a non-transferred DC thermal plasma jet

    International Nuclear Information System (INIS)

    Kumar, S.; Selvarajan, V.

    2008-01-01

    In this paper, the results of plasma spheroidization of iron powders using a DC non-transferred plasma spray torch are presented. The morphology of the processed powders was characterized through scanning electron microscopy (SEM) and optical microscopy (OM). The percentages of spheroidized powders were calculated by the shape factors such as the Irregularity Parameter (IP) and Roundness (RN). A maximum of 83% of spheroidization can be achieved. The spheroidization results are compared with the theoretical estimation and they are found to be in good agreement. The phase composition of the spheroidized powder was analyzed by XRD. The effect of plasma jet temperature and plasma gas flow rate on spheroidization is discussed. At low plasma gas flow rates and at high plasma jet temperatures, the percentage of spheroidization is high

  18. The Role of Higher-Order Modes on the Electromagnetic Whistler-Cyclotron Wave Fluctuations of Thermal and Non-Thermal Plasmas

    Science.gov (United States)

    Vinas, Adolfo F.; Moya, Pablo S.; Navarro, Roberto; Araneda, Jamie A.

    2014-01-01

    Two fundamental challenging problems of laboratory and astrophysical plasmas are the understanding of the relaxation of a collisionless plasmas with nearly isotropic velocity distribution functions and the resultant state of nearly equipartition energy density with electromagnetic plasma turbulence. Here, we present the results of a study which shows the role that higher-order-modes play in limiting the electromagnetic whistler-like fluctuations in a thermal and non-thermal plasma. Our main results show that for a thermal plasma the magnetic fluctuations are confined by regions that are bounded by the least-damped higher order modes. We further show that the zone where the whistler-cyclotron normal modes merges the electromagnetic fluctuations shifts to longer wavelengths as the beta(sub e) increases. This merging zone has been interpreted as the beginning of the region where the whistler-cyclotron waves losses their identity and become heavily damped while merging with the fluctuations. Our results further indicate that in the case of nonthermal plasmas, the higher-order modes do not confine the fluctuations due to the effective higher-temperature effects and the excess of suprathermal plasma particles. The analysis presented here considers the second-order theory of fluctuations and the dispersion relation of weakly transverse fluctuations, with wave vectors parallel to the uniform background magnetic field, in a finite temperature isotropic bi-Maxwellian and Tsallis-kappa-like magnetized electron-proton plasma. Our results indicate that the spontaneously emitted electromagnetic fluctuations are in fact enhanced over these quasi modes suggesting that such modes play an important role in the emission and absorption of electromagnetic fluctuations in thermal or quasi-thermal plasmas.

  19. Thermal conductivity reduction of tungsten plasma facing material due to helium plasma irradiation in PISCES using the improved 3-omega method

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Shuang [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Simmonds, Michael [Department of Physics, University of California, San Diego, La Jolla, CA 92093 (United States); Center for Energy Research, University of California, San Diego, La Jolla, CA 92093 (United States); Qin, Wenjing; Ren, Feng [School of Physics and Technology, Wuhan University, Wuhan, Hubei 430072 (China); Tynan, George R. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Center for Energy Research, University of California, San Diego, La Jolla, CA 92093 (United States); Doerner, Russell P. [Center for Energy Research, University of California, San Diego, La Jolla, CA 92093 (United States); Chen, Renkun, E-mail: rkchen@ucsd.edu [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Center for Energy Research, University of California, San Diego, La Jolla, CA 92093 (United States)

    2017-04-01

    The near-surface region of plasma facing material (PFM) plays an important role in thermal management of fusion reactors. In this work, we measured thermal conductivity of tungsten (W) surface layers damaged by He plasma in PISCES at UCSD. We studied the damage effect on both bulk, and thin film, W. We observed that the surface morphology of both bulk and thin film was altered after exposure to He plasma with the fluence of 1 × 10{sup 26} m{sup −2} (bulk) and 2 × 10{sup 24} m{sup −2} (thin film). Transmission electron microscopy (TEM) analysis reveals that the depth of the irradiation damaged layer was approximately 20 nm on the bulk W exposed to He plasma at 773 K for 2000 s. In order to measure the thermal conductivity of this exceedingly thin damaged layer in the bulk W, we adopted the well-established ‘3-omega’ method and employed novel nanofabrication techniques to improve the measurement sensitivity. For the damaged W thin film sample, we measured the reduction in electrical conductivity and used the Wiedemann-Franz (W-F) law to extract the thermal conductivity. Results from both measurements show that thermal conductivity in the damaged layers was reduced by at least ∼80% compared to that of undamaged W. This large reduction in thermal conductivity can be attributed to the scattering of electrons, the dominant heat carriers in W, caused by defects introduced by He plasma irradiation.

  20. Growth and male reproduction improvement of non-thermal dielectric barrier discharge plasma treatment on chickens

    Science.gov (United States)

    Jiao Zhang, Jiao; Luong Huynh, Do; Chandimali, Nisansala; Kang, Tae Yoon; Kim, Nameun; Mok, Young Sun; Kwon, Taeho; Jeong, Dong Kee

    2018-05-01

    This study investigated whether plasma treatment of fertilized eggs before hatching could affect the growth and reproduction of chickens. Three point five-day-incubated fertilized eggs exposed to non-thermal dielectric barrier discharge plasma at 2.81 W of power for 2 min resulted in the highest growth in chickens. Plasma growth-promoting effect was regulated by the reactive oxygen species homeostasis and the improvement of energy metabolism via increasing serum hormones and adenosine triphosphate levels which were resulted from the regulation of genes involved in antioxidant defense, hormone biosynthesis and energetic metabolism. Interestingly, plasma-treated male chickens conspicuously grew faster than females. Further, aspects of male reproductive system (testosterone level and sperm quality) were improved by the plasma treatment but female reproduction (estradiol and progesterone levels, egg-laying rate and egg weight) had no significant changes. Unfortunately, offspring whose parents were the optimal plasma-treated chickens did not show any difference on growth characteristics and failed to inherit excellent growth features from their parents. Our results suggest a new method to improve the growth rate and male reproductive capacity in poultry but it is only effective in the plasma direct-treated generation.

  1. Application of pulsed power and power modulation to the non-thermal plasma treatment of hazardous gaseous wastes

    International Nuclear Information System (INIS)

    Penetrante, B.M.

    1992-10-01

    Acid rain, global warming, ozone depletion, and smog are preeminent environmental problems facing the world today. Non-thermal plasma techniques offer an innovative approach to the cost-effective solution of these problems. Many potential applications of non-thermal plasmas to air pollution control have already been demonstrated. The use of pulsed power and power modulation is essential to the successful implementation of non-thermal plasma techniques. This paper provides an overview of the most recent developments in non-thermal plasma systems that have been applied to gaseous waste treatment. In the non-thermal plasma approach, the nonequilibrium properties of the plasma are fully exploited. These plasmas are characterized by high electron temperatures, while the gas remains at near ambient temperature and pressure. The energy is directed preferentially to the undesirable components, which are often present in very small concentrations. These techniques utilize the dissociation and ionization of the background gas to produce radicals which, in turn, decompose the toxic compounds. The key to success in the non-thermal plasma approach is to produce a discharge in which the majority of the electrical energy goes into the production of energetic electrons, rather than into gas heating. For example, in a typical application to flue gas cleanup, these electrons produce radicals, such as O and OH, through the dissociation or ionization of molecules such as H 2 O or O 2 . The radicals diffuse through the gas and preferentially oxidize the nitrogen oxides and sulfur oxides to form acids that can then be easily neutralized to form non-toxic, easily-collectible (and commercially salable) compounds. Non-thermal plasmas can be created in essentially two different ways: by electron-beam irradiation, and by electrical discharges

  2. Plasma turbulence effects on aurorae

    International Nuclear Information System (INIS)

    Mishin, E.V.; Telegin, V.A.

    1989-01-01

    Analysis of modern state of microprocesses physics in plasma of aurorare, initiated by energetic electron flow intrusion, is presented. It is shown that there is a number of phenomena, which cannot be explained under non-collision (collective) mechanisms of interaction are applied. Effects of plasma turbulence in the area of auroral arcs are considered. Introduction of a new structural element to auroral arc - plasma-turbulence (PT) layer is substantiated. Numerical simulation of electron kinetics, changes in neutral composition, as well as generation of IR- and UV-radiation in PT layer has been realized

  3. Thermal and oxidation effects

    Energy Technology Data Exchange (ETDEWEB)

    Adamcova, J.; Kolaoikova, I. [Prague Univ., Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles (Czech Republic); Adamcova, J. [Czech Geological Survey, Geologicka 6, Prague (Czech Republic); Kaufhold, S.; Dohrmann, R. [BGR, Federal Institute for Geoscience and Natural Resources, Hannover (Germany); Dohrmann, R. [LBEG, State Authority for Mining, Energy, and Geology, Hannover (Germany); Craen, M. de; Van Geet, M.; Honty, M.; Wang, L.; Weetjens, E. [CK-CEN - Belgian Nuclear Research Centre - Environment, Healt and Safety Institute, Mol (Belgium); Van Geet, M. [ONDRAF/NIRAS - Belgian Agency for Radioactive Waste and Enriched Fissile Materials, Brussel (Belgium); Pozzi, J.P.; Janots, D. [Ecole Normale Paris, CNRS Lab. de Geologie, 75 - Paris (France); Aubourg, C. [Universite Cergy Pontoise, CNRS Lab. de Tectonique, 95 (France); Cathelineau, M.; Rousset, D.; Ruck, R. [Nancy-1 Univ. Henri Poincare, CNRS G2R, 54 (France); Clauer, N. [Strasbourg-1 Univ., CNRS CGS, 67 (France); Liewig, N. [Institut Pluridisciplinaire Hubert Curien, CNRS, 67 - Strasbourg (France); Techer, I. [Nimes Univ., CNRS Cerege, 30 (France)

    2007-07-01

    This session gathers 4 articles dealing with: the alteration processes in bentonites: mineralogical and structural changes during long-term and short-term experiments (J. Adamcov, I. Kolarikova); the implications from the lot experiment regarding the selection of an optimum HLRW bentonite (S. Kaufhold, R. Dohrmann); the extent of oxidation in Boom clay as a result of excavation and ventilation of the HADES URF: Experimental and modelling assessments (M. De Craen, M. Van Geet, M. Honty, L. Wang, E. Weetjens); and the magnetic and mineralogical alterations under thermal stress at 95 deg. C of Callovo-Oxfordian clay-stones (Bure, France) and lower Dogger Mont Terri clay-stones, Switzerland (J.P. Pozzi, C. Aubourg, D. Janots, M. Cathelineau, N. Clauer, D. Rousset, R. Ruck, N. Liewig, I. Techer)

  4. Magnetic field approaches in dc thermal plasma modelling

    International Nuclear Information System (INIS)

    Freton, P; Gonzalez, J J; Masquere, M; Reichert, Frank

    2011-01-01

    The self-induced magnetic field has an important role in thermal plasma configurations generated by electric arcs as it generates velocity through Lorentz forces. In the models a good representation of the magnetic field is thus necessary. Several approaches exist to calculate the self-induced magnetic field such as the Maxwell-Ampere formulation, the vector potential approach combined with different kinds of boundary conditions or the Biot and Savart (B and S) formulation. The calculation of the self-induced magnetic field is alone a difficult problem and only few papers of the thermal plasma community speak on this subject. In this study different approaches with different boundary conditions are applied on two geometries to compare the methods and their limitations. The calculation time is also one of the criteria for the choice of the method and a compromise must be found between method precision and computation time. The study shows the importance of the current carrying path representation in the electrode on the deduced magnetic field. The best compromise consists of using the B and S formulation on the walls and/or edges of the calculation domain to determine the boundary conditions and to solve the vector potential in a 2D system. This approach provides results identical to those obtained using the B and S formulation over the entire domain but with a considerable decrease in calculation time.

  5. Theoretical investigation of thermophysical properties in two-temperature argon-helium thermal plasma

    International Nuclear Information System (INIS)

    Sharma, Rohit; Singh, Kuldip; Singh, Gurpreet

    2011-01-01

    The thermophysical properties of argon-helium thermal plasma have been studied in the temperature range from 5000 to 40 000 K at atmospheric pressure in local thermodynamic equilibrium and non-local thermodynamic equilibrium conditions. Two cases of thermal plasma considered are (i) ground state plasma in which all the atoms and ions are assumed to be in the ground state and (ii) excited state plasma in which atoms and ions are distributed over various possible excited states. The influence of electronic excitation and non-equilibrium parameter θ = T e /T h on thermodynamic properties (composition, degree of ionization, Debye length, enthalpy, and total specific heat) and transport properties (electrical conductivity, electron thermal conductivity, and thermal diffusion ratio) have been studied. Within the framework of Chapman-Enskog method, the higher-order contributions to transport coefficient and their convergence are studied. The influence of different molar compositions of argon-helium plasma mixture on convergence of higher-orders is investigated. Furthermore, the effect of different definitions of Debye length has also been examined for electrical conductivity and it is observed that electrical conductivity with the definition of Debye length (in which only electrons participate in screening) is less than that of the another definition (in which both the electrons and ions participate in screening) and this deviation increases with electron temperature. Finally, the effect of lowering of ionization energy is examined on electron number density, Debye length, and higher-order contribution to electrical conductivity. It is observed that the lowering of the ionization energy affects the electron transport-properties and consequently their higher-order contributions depending upon the value of the non-equilibrium parameter θ.

  6. Development and evaluation of suspension plasma sprayed yttria stabilized zirconia coatings as thermal barriers

    Science.gov (United States)

    van Every, Kent J.

    The insulating effects from thermal barrier coatings (TBCs) in gas turbine engines allow for increased operational efficiencies and longer service lifetimes. Consequently, improving TBCs can lead to enhanced gas turbine engine performance. This study was conducted to investigate if yttria-stabilized zirconia (YSZ) coatings, the standard industrial choice for TBCs, produced from nano-sized powder could provide better thermal insulation than current commericial YSZ coatings generated using micron-sized powders. The coatings for this research were made via the recently developed suspension plasma spraying (SPS) process. With SPS, powders are suspended in a solvent containing dispersing agents; the suspension is then injected directly into a plasma flow that evaporates the solvent and melts the powder while transporting it to the substrate. Although related to the industrial TBC production method of air plasma spraying (APS), SPS has two important differences---the ability to spray sub-micron diameter ceramic particles, and the ability to alloy the particles with chemicals dissolved in the solvent. These aspects of SPS were employed to generate a series of coatings from suspensions containing ˜100 nm diameter YSZ powder particles, some of which were alloyed with neodymium and ytterbium ions from the solvent. The SPS coatings contained columnar structures not observed in APS TBCs; thus, a theory was developed to explain the formation of these features. The thermal conductivity of the coatings was tested to evaluate the effects of these unique microstructures and the effects of the alloying process. The results for samples in the as-sprayed and heat-treated conditions were compared to conventional YSZ TBCs. This comparison showed that, relative to APS YSZ coatings, the unalloyed SPS samples typically exhibited higher as-sprayed and lower heat-treated thermal conductivities. All thermal conductivity values for the alloyed samples were lower than conventional YSZ TBCs

  7. On reliability of 3D reconstructions of thermal plasma jet radiation by inverse Radon transform

    Czech Academy of Sciences Publication Activity Database

    Sekerešová, Zuzana; Hlína, Jan

    2011-01-01

    Roč. 56, č. 2 (2011), s. 171-183 ISSN 0001-7043 Institutional research plan: CEZ:AV0Z20570509 Keywords : thermal plasma jet * tomography * image reconstruction Subject RIV: BL - Plasma and Gas Discharge Physics

  8. Thermal effects in concrete members

    International Nuclear Information System (INIS)

    Kar, A.K.

    1977-01-01

    When subjected to temperature changes and restrained from free movement, a member develops stresses. Restrained members are sometimes assumed to act independently of other members. A method of analysis and design for thermal stresses in such members is provided. The method of analysis, based on the ultimate strength concept, greatly reduces the computational efforts for determining thermal effects in concrete members. Available charts and tables and the recommendations given herein simplify the design. (Auth.)

  9. Strongly coupled Coulomb systems with positive dust grains: thermal and UV-induced plasmas

    International Nuclear Information System (INIS)

    Samarian, A.A.

    2000-01-01

    Full text: A plasma containing macroscopic dust particles or grains (often referred to as a dusty or colloidal or complex plasma) has the feature that grains may be charged by electron or ion flux or by photo- or thermoelectron emission. Electron emission from a grain surface produces a positive charge; capture of electrons produces the reverse effect making the dust grains negatively charged. Most dusty plasma research is concerned with the ordered dust structures (so-called 'plasma crystal') in glow discharges. The dust grains in these experiments were found to carry a negative charge due to the higher mobility of electrons as compared to ions in the discharge plasma. In recent years, in parallel with the study of the properties of plasma crystals under discharge conditions, attempts to obtain a structure from positively charged dust grains have been made, and structure formation processes for various charging mechanisms, particularly thermoelectron emission and photoemission, have been investigated. In this paper we review the essential features of strongly coupled plasmas with positive dust grains. An ordered structure of CeO 2 grains has been experimentally observed in a combustion products jet. The grains were charged positively and suspended in the plasma flow. Their charge is about 10 3 a and the calculated value of a Coulomb coupling parameter Γ is >10, corresponding to a plasma liquid. The ordered structures of Al 2 O 3 dust grains in propellant combustion products plasma have been observed for the first time. These structures were found in the sheath boundary of condensation region. The obtained data let us estimate the value of parameter Γ =3-40, corresponding to the plasma liquid state. The possibility is studied of the formation of ordered dust grain structures in thermal plasma. The range of the required values of the coupling parameter Γ is calculated using the results of diagnostic measurements carried out in thermal plasma with grains of

  10. Role of thermo-physical properties on design and development of thermal plasma devices

    International Nuclear Information System (INIS)

    Ghorui, S.

    2014-01-01

    Thermal plasma devices find wide application in variety of technological areas like cutting, welding, spray coating, waste management, material processing, chemical reduction, nano-synthesis, novel material synthesis etc. Highly non-linear behavior of the plasma properties coupled with inherent instabilities, extremely high temperature, high gradients in thermal, and flow field, presence of thermal and chemical non-equilibrium make design and development of the plasma generating devices a challenging task as power levels of the devices increase

  11. Thermal energy and bootstrap current in fusion reactor plasmas

    International Nuclear Information System (INIS)

    Becker, G.

    1993-01-01

    For DT fusion reactors with prescribed alpha particle heating power P α , plasma volume V and burn temperature i > ∼ 10 keV specific relations for the thermal energy content, bootstrap current, central plasma pressure and other quantities are derived. It is shown that imposing P α and V makes these relations independent of the magnitudes of the density and temperature, i.e. they only depend on P α , V and shape factors or profile parameters. For model density and temperature profiles analytic expressions for these shape factors and for the factor C bs in the bootstrap current formula I bs ∼ C bs (a/R) 1/2 β p I p are given. In the design of next-step devices and fusion reactors, the fusion power is a fixed quantity. Prescription of the alpha particle heating power and plasma volume results in specific relations which can be helpful for interpreting computer simulations and for the design of fusion reactors. (author) 5 refs

  12. Special problems: LBB, thermal effects

    International Nuclear Information System (INIS)

    Lin Chiwen

    2001-01-01

    This section presents the discussion of special problems in the reactor coolant system design, including LBB and thermal effects. First, the categories of fracture mechanics technology applicable to LBB is discussed. Two categories of fracture mechanics, namely: linear-elastic fracture mechanics (LEFM) and elastic-plastic fracture mechanics (EPFM) are discussed specifically. Next, basic concepts of LEFM are discussed. This will be followed by a discussion of EPFM, with more specific discussion of the methodology currently acceptable to NRC, with the emphasis on the J-integral approach. This is followed by a discussion of the NRC position and recommendations and basic requirements laid out by NRC. A specific example of LBB application to WPWR piping is used to identify the key steps to be followed, in order to satisfy the recommendations and requirements of NRC. An application of LBB to the WPWR reactor coolant loop piping is provided as further illustration of the methodology. This section focuses on the thermal effects which have not been addressed earlier, and the thermal effects which have caused particular concerns on potential reactor degradations, such as pressurized thermal shocks. The organization of this section is divided into the following subsections: linear-elastic fracture mechanics (LEFM); elastic-plastic fracture mechanics (EPFM); J concepts; NRC recommendations and requirements on the application of LBB; two specific applications of LBB to WPWR piping; PWR internals degradation; thermal fatigue considerations; a case study of pressurized thermal shock

  13. Atmospheric non-thermal argon-oxygen plasma for sunflower seedling growth improvement

    Science.gov (United States)

    Matra, Khanit

    2018-01-01

    Seedling growth enhancement of sunflower seeds by DC atmospheric non-thermal Ar-O2 plasma has been proposed. The plasma reactor was simply designed by the composition of multi-pin electrodes bonded on a solderable printed circuit board (PCB) anode. A stable plasma was exhibited in the non-periodical self-pulsing discharge mode during the seed treatment. The experimental results showed that non-thermal plasma treatment had a significant positive effect on the sunflower seeds. Ar-O2 mixed gas ratio, treatment time and power source voltage are the important parameters affecting growth stimulation of sunflower sprouts. In this research, the sunflower seeds treated with 3:3 liters per minute (LPM) of Ar-O2 plasma at a source voltage of 8 kV for 1 min showed the best results in stimulating the seedling growth. The results in this case showed that the dry weight and average shoot length of the sunflower sprouts were 1.79 and 2.69 times higher and heavier than those of the untreated seeds, respectively.

  14. Destruction studies of hazardous wastes by thermal plasma; Estudios de degradacion de residuos peligrosos mediante plasma termico

    Energy Technology Data Exchange (ETDEWEB)

    Cota S, G

    1998-11-01

    Plasma technology appears promising because its high degree of controllability, capability to process waste without the adverse effects of combustion, and a very wide temperature range of operation. The goal of this work was to develop a process for a high throughput system to turn hazardous waste into inert stable products, which can be safely stored and to greatly reduce air pollution relative to incineration. The experiments have shown that the thermal plasma reactor can provide a high degree of decomposition of CCl{sub 4} , C{sub 6} H{sub 6}, C{sub 2} Cl{sub 4} and commercial oil at low gas input speeds, with modest power requirements. Decomposition of 99.9999 % has been obtained in our laboratory and all the organic components are decomposed in base molecules (C, CO, CO{sub 2}, H{sub 2}, HCl). The analysis of exhaust gases was made by using a mass filter quadrupole. The equipment consist of a cylindrical reactor hermetically sealed, double-walled and water-cooled container made of special steel, this container in halt the crucible which serves to receive the waste materials. The whole system is designed for a maximal internal temperature of 2000 Centigrade. The gaseous result components of the material are transferred to a scrubber unit through an exit arranged on the top of reactor. The thermal efficiency evaluation of the plasma torch was also realized, obtaining a reasonable agreement between measurements and predictions in temperature profiles. (Author)

  15. Chemical and physical reactions under thermal plasmas conditions

    International Nuclear Information System (INIS)

    Fauchais, P.; Vardelle, A.; Vardelle, M.; Coudert, J.F.

    1987-01-01

    Basic understanding of the involved phenomena lags far behind industrial development that requires now a better knowledge of the phenomena to achieve a better control of the process allowing to improve the quality of the products. Thus the authors try to precise what is their actual knowledge in the fields of: plasma generators design; plasma flow models with the following key points: laminar or turbulent flow, heat transfer to walls, 2D or 3D models, non equilibrium effects, mixing problems when chemical reactions are to be taken into account with very fast kinetics, electrode regions, data for transport properties and kinetic rates; nucleation problems; plasma flow characteristics measurements: temperature or temperatures and population of excited states (automatized emission spectroscopy, LIF, CARS) as well as flow velocity (LDA with small particles, Doppler effects...); plasma and particles momentum and heat transfer either with models taking into account particles size and injection velocity distributions, heat propagation, vaporization, Kundsen effect, turbulences ... or with measurements: particles velocity and flux distributions (Laser Anemometry) as well as surface temperature distributions (two colour pyrometry in flight statistical or not)

  16. Synthesis of Ni2B nanoparticles by RF thermal plasma for fuel cell catalyst

    International Nuclear Information System (INIS)

    Cheng, Y; Tanaka, M; Watanabe, T; Choi, S Y; Shin, M S; Lee, K H

    2014-01-01

    The catalyst of Ni 2 B nanoparticles was successfully prepared using nickel and boron as precursors with the quenching gas in radio frequency thermal plasmas. The generating of Ni 2 B needs adequate reaction temperature and boron content in precursors. The quenching gas is beneficial for the synthesis of Ni 2 B in RF thermal plasma. The effect of quenching rate, powder feed rate and boron content in feeding powders on the synthesis of nickel boride nanoparticles was studied in this research. The high mass fraction of 28 % of Ni 2 B nanoparticles can be generated at the fixed initial composition of Ni:B = 2:3. Quenching gas is necessary in the synthesis of Ni 2 B nanoaprticles. In addition, the mass fraction of Ni 2 B increases with the increase of quenching gas flow rate and powder feed rate

  17. Simulations of planar non-thermal plasma assisted ignition at atmospheric pressure

    KAUST Repository

    Casey, Tiernan A.

    2016-10-21

    The opportunity for ignition assistance by a pulsed applied voltage is investigated in a canonical one-dimensional configuration. An incipient ignition kernel, formed by localized energy deposition into a lean mixture of methane and air at atmospheric pressure, is subjected to sub-breakdown electric fields (E/N ≈ 100 Td) by a DC potential applied across the domain, resulting in non-thermal behavior of the plasma formed during the discharge. A two-fluid approach is employed to couple thermal neutrals and ions to the non-thermal electrons. A two-temperature plasma mechanism describing gas phase combustion, excitation of neutral species, and high-energy electron kinetics is employed to account for non-thermal effects. Charged species transported from the ignition zone drift rapidly through the domain, augmenting the magnitude of the electric field in the fresh gas during the pulse through a dynamic-electrode effect, which results in an increase in the energy of the electrons in the fresh mixture with increasing time. Enhanced fuel and oxidizer decomposition due to electron impact dissociation and interaction with excited neutrals generate a pool of radicals, mostly O and H, in the fresh gas ahead of the flame\\'s preheat zone. In the configuration considered, the effect of the nanosecond pulse is to increase the mass of fuel burned at equivalent times relative to the unsupported ignition through enhanced radical generation, resulting in an increased heat release rate in the immediate aftermath of the pulse.

  18. Finite length thermal equilibria of a pure electron plasma column

    International Nuclear Information System (INIS)

    Prasad, S.A.; O'Neil, T.M.

    1979-01-01

    The electrons of a pure electron plasma may be in thermal equilibrium with each other and still be confined by static magnetic and electric fields. Since the electrons make a significant contribution to the electric field, only certain density profiles are consistent with Poisson's equation. The class of such distributions for a finite length cylindrical column is investigated. In the limit where the Debye length is small compared with the dimensions of the column, the density is essentially constant out to some surface of revolution and then falls off abruptly. The falloff in density is a universal function when measured along the local normal to the surface of revolution and scaled in terms of the Debye length. The solution for the shape of the surface of revolution is simplified by passage to the limit of zero Debye length

  19. Maximum thermal energy density in magnetically confined plasmas

    International Nuclear Information System (INIS)

    Coppi, B.

    1977-01-01

    The consequences of the limiting value of β that follows from analyzing the onset of high temperature ballooning modes is examined in high temperature regimes where the ideal MHD approximation is not strictly valid and for finite-β configurations exhibiting the main features of those that are obtained by magnetic flux conservation. These modes are localized over periodically space intervals of a given magnetic field line and are driven by the combined effects of finite plasma pressure and the locally unfavorable magnetic curvature. The effects of finite β, insofar as they shorten the effective connection length, steepen the pressure gradient, and influence the magnetic well dug by the plasma, are studied using a model dispersion relation. 14 references

  20. Synthesis of cobalt boride nanoparticles using radio frequency thermal plasma

    International Nuclear Information System (INIS)

    Lapitan, Jr. Lorico DS.; Ying Ying Chen; Seesoek Choe; Watanabe, Takayuki

    2012-01-01

    Nano size cobalt boride particles were synthesized from vapor phase using a 30 kw-4 MHz radio frequency (RF) thermal plasma. Cobalt and boron powder mixtures used as precursors in different composition and feed rate were evaporated immediately in the high temperature plasma and cobalt boride nanoparticles were produced through the quenching process. The x-ray diffractometry (XRD) patterns of cobalt boride nanoparticles prepared from the feed powder ratio of 1:2 and 1:3 for Co: B showed peaks that are associated with the Co 2 B and CoB crystal phases of cobalt boride. The XRD analysis revealed that increasing the powder feed rate results in a higher mass fraction and a larger crystalline diameter of cobalt boride nanoparticles. The images obtained by field emission scanning electron microscopy (FE-SEM) revealed that cobalt boride nanoparticles have a spherical morphology. The crystallite size of the particles estimated with XRD was found to be 18-22 nm. (author)

  1. Coulomb thermal properties and stability of the Io plasma torus

    Science.gov (United States)

    Barbosa, D. D.; Coroniti, F. V.; Eviatar, A.

    1983-01-01

    Coulomb collisional energy exchange rates are computed for a model of the Io plasma torus consisting of newly created pickup ions, a background of thermally degraded intermediary ions, and a population of cooler electrons. The electrons are collisionally heated by both the pickup ions and background ions and are cooled by electron impact excitation of plasma ions which radiate in the EUV. It is found that a relative concentration of S III pickup ions forbidden S III/electrons = 0.1 with a temperature of 340 eV can deliver energy to the electrons at a rate of 3 x 10 to the -13th erg/cu cm per sec, sufficient to power the EUV emissions in the Io torus. The model predicts a background ion temperature Ti of about 53 eV and an electron temperature Te of about 5.5 eV on the basis of steady-state energy balance relations at Coulomb rates. The model also predicts electron temperature fluctuations at the 30 percent level on a time scale of less than 11 hours, consistent with recent observations of this phenomenon.

  2. Non-thermal plasma technology for the development of antimicrobial surfaces: a review

    Science.gov (United States)

    Nikiforov, Anton; Deng, Xiaolong; Xiong, Qing; Cvelbar, U.; DeGeyter, N.; Morent, R.; Leys, Christophe

    2016-05-01

    Antimicrobial coatings are in high demand in many fields including the biomaterials and healthcare sectors. Within recent progress in nanoscience and engineering at the nanoscale, preparation of nanocomposite films containing metal nanoparticles (such as silver nanoparticles, copper nanoparticles, zinc oxide nanoparticles) is becoming an important step in manufacturing biomaterials with high antimicrobial activity. Controlled release of antibiotic agents and eliminating free nanoparticles are of equal importance for engineering antimicrobial nanocomposite materials. Compared to traditional chemical ‘wet’ methods, plasma deposition and plasma polymerization are promising approaches for the fabrication of nanocomposite films with the advantages of gas phase dry processes, effective use of chemicals and applicability to various substrates. In this article, we present a short overview of state-of-the-art engineering of antimicrobial materials based on the use of non-thermal plasmas at low and atmospheric pressure.

  3. Richtmyer–Meshkov instability of a thermal interface in a two-fluid plasma

    KAUST Repository

    Bond, D.

    2017-11-03

    We computationally investigate the Richtmyer–Meshkov instability of a density interface with a single-mode perturbation in a two-fluid, ion–electron plasma with no initial magnetic field. Self-generated magnetic fields arise subsequently. We study the case where the density jump across the initial interface is due to a thermal discontinuity, and select plasma parameters for which two-fluid plasma effects are expected to be significant in order to elucidate how they alter the instability. The instability is driven via a Riemann problem generated precursor electron shock that impacts the density interface ahead of the ion shock. The resultant charge separation and motion generates electromagnetic fields that cause the electron shock to degenerate and periodically accelerate the electron and ion interfaces, driving Rayleigh–Taylor instability. This generates small-scale structures and substantially increases interfacial growth over the hydrodynamic case.

  4. Thermal plasma spraying for SOFCs: Applications, potential advantages, and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Hui, Rob; Wang, Zhenwei; Jankovic, Jasna; Yick, Sing; Maric, Radenka; Ghosh, Dave [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Kesler, Olivera [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Department of Mechanical Engineering, University of British Columbia, 2054-6250 Applied Science Lane, Vancouver, BC V6T 1Z4 (Canada); Rose, Lars [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Department of Materials Engineering, University of British Columbia, 309-6350 Stores Road, Vancouver, BC V6T 1Z4 (Canada)

    2007-07-10

    In this article, the applications, potential advantages, and challenges of thermal plasma spray (PS) processing for nanopowder production and cell fabrication of solid oxide fuel cells (SOFCs) are reviewed. PS processing creates sufficiently high temperatures to melt all materials fed into the plasma. The heated material can either be quenched into oxide powders or deposited as coatings. This technique has been applied to directly deposit functional layers as well as nanopowder for SOFCs application. In particularly, low melting point and highly active electrodes can be directly fabricated on zirconia-based electrolytes. This is a simple processing technique that does not require the use of organic solvents, offering the opportunity for flexible adjustment of process parameters, and significant time saving in production of the cell and cost reduction compared with tape casting, screen printing and sintering processing steps. Most importantly, PS processing shows strong potential to enable the deposition of metal-supported SOFCs through the integrated fabrication of membrane-electrode assemblies (MEA) on porous metallic substrates with consecutive deposition steps. On the other hand, the application of PS processing to produce SOFCs faces some challenges, such as insufficient porosity of the electrodes, the difficulty of obtaining a thin (<10 {mu}m) and dense electrolyte layer. Fed with H{sub 2} as the fuel gas and oxygen as the oxidant gas, the plasma sprayed cell reached high power densities of 770 mW cm{sup -2} at 900 C and 430 mW cm{sup -2} at 800 C at a cell voltage of 0.7 V. (author)

  5. Numerical modeling of disperse material evaporation in axisymmetric thermal plasma reactor

    Directory of Open Access Journals (Sweden)

    Stefanović Predrag Lj.

    2003-01-01

    Full Text Available A numerical 3D Euler-Lagrangian stochastic-deterministic (LSD model of two-phase flow laden with solid particles was developed. The model includes the relevant physical effects, namely phase interaction, panicle dispersion by turbulence, lift forces, particle-particle collisions, particle-wall collisions, heat and mass transfer between phases, melting and evaporation of particles, vapour diffusion in the gas flow. It was applied to simulate the processes in thermal plasma reactors, designed for the production of the ceramic powders. Paper presents results of extensive numerical simulation provided (a to determine critical mechanism of interphase heat and mass transfer in plasma flows, (b to show relative influence of some plasma reactor parameters on solid precursor evaporation efficiency: 1 - inlet plasma temperature, 2 - inlet plasma velocity, 3 - particle initial diameter, 4 - particle injection angle a, and 5 - reactor wall temperature, (c to analyze the possibilities for high evaporation efficiency of different starting solid precursors (Si, Al, Ti, and B2O3 powder, and (d to compare different plasma reactor configurations in conjunction with disperse material evaporation efficiency.

  6. Using plasma-fuel systems at Eurasian coal-fired thermal power stations

    Science.gov (United States)

    Karpenko, E. I.; Karpenko, Yu. E.; Messerle, V. E.; Ustimenko, A. B.

    2009-06-01

    The development of plasma technology for igniting solid fuels at coal-fired thermal power stations in Russia, Kazakhstan, China, and other Eurasian countries is briefly reviewed. Basic layouts and technical and economic characteristics of plasma-fuel systems installed in different coal-fired boiles are considered together with some results from using these systems at coal-fired thermal power stations.

  7. Spheroidization of molybdenum powder by radio frequency thermal plasma

    Science.gov (United States)

    Liu, Xiao-ping; Wang, Kuai-she; Hu, Ping; Chen, Qiang; Volinsky, Alex A.

    2015-11-01

    To control the morphology and particle size of dense spherical molybdenum powder prepared by radio frequency (RF) plasma from irregular molybdenum powder as a precursor, plasma process parameters were optimized in this paper. The effects of the carrier gas flow rate and molybdenum powder feeding rate on the shape and size of the final products were studied. The molybdenum powder morphology was examined using high-resolution scanning electron microscopy. The powder phases were analyzed by X-ray diffraction. The tap density and apparent density of the molybdenum powder were investigated using a Hall flow meter and a Scott volumeter. The optimal process parameters for the spherical molybdenum powder preparation are 50 g/min powder feeding rate and 0.6 m3/h carrier gas rate. In addition, pure spherical molybdenum powder can be obtained from irregular powder, and the tap density is enhanced after plasma processing. The average size is reduced from 72 to 62 µm, and the tap density is increased from 2.7 to 6.2 g/cm3. Therefore, RF plasma is a promising method for the preparation of high-density and high-purity spherical powders.

  8. Dynamic plasma screening effects on electron capture process in hydrogenic ion fully stripped ion collisions in dense plasmas

    International Nuclear Information System (INIS)

    Jung, Y.

    1997-01-01

    In dense plasmas, dynamic plasma screening effects are investigated on electron capture from hydrogenic ions by past fully stripped ions. The classical Bohr Lindhard model has been applied to obtain the electron capture probability. The interaction potential in dense plasmas is represented in terms of the longitudinal dielectric function. The classical straight-line trajectory approximation is applied to the motion of the projectile ion in order to visualize the electron capture probability as a function of the impact parameter, projectile energy, and plasma parameters. The electron capture probability including the dynamic plasma screening effect is always greater than that including the static plasma screening effect. When the projectile velocity is smaller than the electron thermal velocity, the dynamic polarization screening effect becomes the static plasma screening effect. When the projectile velocity is greater than the plasma electron thermal velocity, the interaction potential is almost unshielded. The difference between the dynamic and static plasma screening effects is more significant for low energy projectiles. It is found that the static screening formula obtained by the Debye Hueckel model overestimates the plasma screening effects on the electron capture processes in dense plasmas. copyright 1997 American Institute of Physics

  9. Invert Effective Thermal Conductivity Calculation

    International Nuclear Information System (INIS)

    M.J. Anderson; H.M. Wade; T.L. Mitchell

    2000-01-01

    The objective of this calculation is to evaluate the temperature-dependent effective thermal conductivities of a repository-emplaced invert steel set and surrounding ballast material. The scope of this calculation analyzes a ballast-material thermal conductivity range of 0.10 to 0.70 W/m · K, a transverse beam spacing range of 0.75 to 1.50 meters, and beam compositions of A 516 carbon steel and plain carbon steel. Results from this calculation are intended to support calculations that identify waste package and repository thermal characteristics for Site Recommendation (SR). This calculation was developed by Waste Package Department (WPD) under Office of Civilian Radioactive Waste Management (OCRWM) procedure AP-3.12Q, Revision 1, ICN 0, Calculations

  10. Suitability of thermal plasmas for large-area bacteria inactivation on temperature-sensitive surfaces – first results with Geobacillus stearothermophilus spores

    International Nuclear Information System (INIS)

    Szulc, M; Schein, S; Schaup, J; Zimmermann, S; Schein, J

    2017-01-01

    The application of thermal plasma for large-area bacteria inactivation on temperature-sensitive surfaces is not a common one. Nonetheless, there are thermal plasma generators which offer a high sheath homogeneity and have proven to be suitable for treatment of thermally sensitive materials in the past. To investigate the suitability of such plasmas, agar dishes plated with endospores of Geobacillus stearothermophilus have been treated with a long arc plasma generator called LARGE. The achieved results have been compared with a commercially available non-thermal plasma generator. A significant inactivation of the endospores could be observed only after 60 s of treatment with the thermal plasma source. This was not possible with the non-thermal generator. Moreover, no temperature damage or increase of the specimen could be detected. An attempt to determine the main agents responsible for the microbicidal effects have been made – the influence of plasma gas composition, discharge current and treatment time has been investigated. Significant improvements in the disinfection rates after adding small amounts of nitrogen to the plasma gas could be observed. A first discussion regarding the suitability of thermal plasmas for bacteria inactivation has been given. (paper)

  11. Thermal effects in concrete members

    International Nuclear Information System (INIS)

    Kar, A.K.

    1977-01-01

    The proposed method of analysis for concrete members subjected to temperature changes is consistent with the requirements of ultimate strength design. This also facilitates the provision of the same safety margin as for other loads. Due to cracks and creep in concrete, thermal stresses are nonlinear; they are dependent on the effective member stiffness, which in turn vary with the magnitude of loading. Therefore it is inconsistent to have an ultimate strength design in conjunction with an analysis based on the linear elastic theory. It is proposed that when the requirements of serviceability are met, the neutral axis corresponding to the ultimate load capacity conditions be considered for temperature-induced loadings. This conforms with the fact that the thermal load, because of creep and formation of cracks in the member, can be self-relieving as the failure load condition or ultimate capacity is approached. The maximum thermal load that can develop in dependent on the effective cross section of the member. Recommendations are made for determining the average effective member stiffness, which lies between the stiffness corresponding to the cracked (at ultimate condition) and the uncracked sections. In the proposed method, thermal stresses are not considered completely self-relieving. The stresses are considered simultaneously with stresses resulting from other causes. A step-by-step approach is presented for analysis and design of concrete members subjected to temperature changes

  12. Induction of Immunogenic Cell Death with Non-Thermal Plasma for Cancer Immunotherapy

    Science.gov (United States)

    Lin, Abraham G.

    Even with the recent advancements in cancer immunotherapy, treatments are still associated with debilitating side effects and unacceptable fail rates. Induction of immunogenic cell death (ICD) in tumors is a promising approach to cancer treatment that may overcome these deficiencies. Cells undergoing ICD pathways enhance the interactions between cancerous cells and immune cells of the patient, resulting in the generation of anti-cancer immunity. The goal of this therapy relies on the engagement and reestablishment of the patient's natural immune processes to target and eliminate cancerous cells systemically. The main objective of this research was to determine if non-thermal plasma could be used to elicit immunogenic cancer cell death for cancer immunotherapy. My hypothesis was that plasma induces immunogenic cancer cell death through oxidative stress pathways, followed by development of a specific anti-tumor immune response. This was tested by investigating the interactions between plasma and multiple cancerous cells in vitro and validating anti-tumor immune responses in vivo. Following plasma treatment, two surrogate ICD markers, secreted adenosine triphosphate (ATP) and surface exposed calreticulin (ecto-CRT), were emitted from all three cancerous cell lines tested: A549 lung carcinoma cell line, CNE-1 radiation-resistant nasopharyngeal cell line and CT26 colorectal cancer cell line. When these cells were co-cultured with macrophages, cells of the innate immune system, the tumoricidal activity of macrophages was enhanced, thus demonstrating the immunostimulatory activity of cells undergoing ICD. The underlying mechanisms of plasma-induced ICD were also evaluated. When plasma is generated, four major components are produced: electromagnetic fields, ultraviolet radiation, and charged and neutral reactive species. Of these, we determined that plasma-generated charged and short-lived reactive oxygen species (ROS) were the major effectors of ICD. Following plasma

  13. Thermal ionization and plasma state of high temperature vapor of UO2, Cs, and Na: Effect on the heat and radiation transport properties of the vapor phase

    International Nuclear Information System (INIS)

    Karow, H.U.

    1979-01-01

    The paper deals with the question how far the thermophysical state and the convective and radiative heat transport properties of vaporized reactor core materials are affected by the thermal ionization existing in the actual vapor state. The materials under consideration here are: nuclear oxide fuel (UO 2 ), Na (as the LMFBR coolant material), and Cs (alkaline fission product, partly retained in the fuel of the core zone). (orig./RW) [de

  14. Thermal analysis of the in-vessel components of the ITER plasma-position reflectometry

    Energy Technology Data Exchange (ETDEWEB)

    Quental, P. B., E-mail: pquental@ipfn.tecnico.ulisboa.pt; Policarpo, H.; Luís, R.; Varela, P. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal)

    2016-11-15

    The ITER plasma position reflectometry system measures the edge electron density profile of the plasma, providing real-time supplementary contribution to the magnetic measurements of the plasma-wall distance. Some of the system components will be in direct sight of the plasma and therefore subject to plasma and stray radiation, which may cause excessive temperatures and stresses. In this work, thermal finite element analysis of the antenna and adjacent waveguides is conducted with ANSYS V17 (ANSYS® Academic Research, Release 17.0, 2016). Results allow the identification of critical temperature points, and solutions are proposed to improve the thermal behavior of the system.

  15. A non-equilibrium simulation of thermal constriction in a cascaded arc hydrogen plasma

    International Nuclear Information System (INIS)

    Peerenboom, K S C; Goedheer, W J; Van Dijk, J; Kroesen, G M W

    2014-01-01

    The cascaded arc hydrogen plasma of Pilot-PSI is studied in a non-LTE model. We demonstrate that the effect of vibrationally excited molecules on the heavy-particle-assisted dissociation is crucial for obtaining thermal constriction. To the best of our knowledge, thermal constriction has not been obtained before in a non-LTE simulation. Probably, realistic numerical studies of this type of plasma were hindered by numerical problems, preventing the non-LTE simulations to show characteristic physical mechanisms such as thermal constriction. In this paper we show that with the help of appropriate numerical strategies thermal constriction can be obtained in a non-LTE simulation. To this end, a new source term linearization technique is developed, which ensures physical solutions even near chemical equilibrium where the composition is dominated by chemical source terms. Results of the model are compared with experiments on Pilot-PSI and show good agreement with pressure and voltage measurements in the source. (paper)

  16. Thermal plasma treatment of cell-phone waste : preliminary result

    Energy Technology Data Exchange (ETDEWEB)

    Ruj, B. [Central Mechanical Engineering Research Inst., Durgapur (India). Thermal Engineering Group; Chang, J.S.; Li, O.L. [McMaster Univ., Hamilton, ON (Canada). Dept. of Engineering Physics; Pietsch, G. [RWTH Aachen Univ., Aachen (Germany)

    2010-07-01

    The cell phone is an indispensable service facilitator, however, the disposal and recycling of cell phones is a major problem. While the potential life span of a mobile phone, excluding batteries, is over 10 years, most of the users upgrade their phones approximately four times during this period. Cell phone waste is significantly more hazardous than many other municipal wastes as it contains thousands of components made of toxic chemicals and metals like lead, cadmium, chromium, mercury, polyvinyl chlorides (PVC), brominated flame retardants, beryllium, antimony and phthalates. Cell phones also use many expensive rare metals. Since cell phones are made up of plastics, metals, ceramics, and trace other substances, primitive recycling or disposal of cell phone waste to landfills and incinerators creates irreversible environmental damage by polluting water and soil, and contaminating air. In order to minimize releases into the environment and threat to human health, the disposal of cell phones needs to be managed in an environmentally friendly way. This paper discussed a safer method of reducing the generation of syngas and hydrocarbons and metal recovery through the treatment of cell phone wastes by a thermal plasma. The presentation discussed the experiment, with particular reference to sample preparation; experimental set-up; and results four samples with different experimental conditions. It was concluded that the plasma treatment of cell phone waste in reduced condition generates gaseous components such as hydrogen, carbon monoxide, and hydrocarbons which are combustible. Therefore, this system is an energy recovery system that contributes to resource conservation and reduction of climate change gases. 5 refs., 2 tabs., 2 figs.

  17. The thermal evolution of targets under plasma focus pulsed ion implantation

    International Nuclear Information System (INIS)

    Sanchez, G.; Feugeas, J.

    1997-01-01

    Pulsed ion beam implantation with plasma focus has proved to be an effective method of metal surface treatment for tribological purposes. Nevertheless, the pulsed nature and the continuous energy spectrum of the ion beams differ from those of the standard ion implantation processes. In this paper a model of the thermal evolution of the surface layers of stainless steel, titanium and copper, during and after nitrogen and argon ion beam incidence, is presented using the finite-difference method. In the calculations, the geometry and physical characteristics of the ion beams, the single-ion-solid interaction process and the thermal properties of the materials were used. The results showed a strong thermal effect consisting in the generation of transitory heating slopes and heating speeds as high as ∼3600 K μm -1 and ∼40 K ns -1 respectively, with maximum temperatures that can reach even the material evaporation point at the surface layers. The cooling down process, through the thermal conduction mechanism at the target bulk, turns out to be fast enough to produce the complete thermal relaxation of the target in only a few microseconds after the end of the ion beam incidence. The results presented are contrasted with experiments performed in similar conditions to those used in the numerical model. (Author)

  18. Nernst Effect in Magnetized Plasmas

    OpenAIRE

    Joglekar, Archis S.; Thomas, Alexander G. R.; Ridgers, Christopher P.; Kingham, Robert J.

    2015-01-01

    We present nanosecond timescale Vlasov-Fokker-Planck-Maxwell modeling of magnetized plasma transport and dynamics in a hohlraum with an applied external magnetic field, under conditions similar to recent experiments. Self-consistent modeling of the kinetic electron momentum equation allows for a complete treatment of the heat flow equation and Ohm's Law, including Nernst advection of magnetic fields. In addition to showing the prevalence of non-local behavior, we demonstrate that effects such...

  19. Plasma fluorination of vertically aligned carbon nanotubes: functionalization and thermal stability.

    Science.gov (United States)

    Struzzi, Claudia; Scardamaglia, Mattia; Hemberg, Axel; Petaccia, Luca; Colomer, Jean-François; Snyders, Rony; Bittencourt, Carla

    2015-01-01

    Grafting of fluorine species on carbon nanostructures has attracted interest due to the effective modification of physical and chemical properties of the starting materials. Various techniques have been employed to achieve a controlled fluorination yield; however, the effect of contaminants is rarely discussed, although they are often present. In the present work, the fluorination of vertically aligned multiwalled carbon nanotubes was performed using plasma treatment in a magnetron sputtering chamber with fluorine diluted in an argon atmosphere with an Ar/F2 ratio of 95:5. The effect of heavily diluted fluorine in the precursor gas mixture is investigated by evaluating the modifications in the nanotube structure and the electronic properties upon plasma treatment. The existence of oxygen-based grafted species is associated with background oxygen species present in the plasma chamber in addition to fluorine. The thermal stability and desorption process of the fluorine species grafted on the carbon nanotubes during the fluorine plasma treatment were evaluated by combining different spectroscopic techniques.

  20. Plasma fluorination of vertically aligned carbon nanotubes: functionalization and thermal stability

    Directory of Open Access Journals (Sweden)

    Claudia Struzzi

    2015-12-01

    Full Text Available Grafting of fluorine species on carbon nanostructures has attracted interest due to the effective modification of physical and chemical properties of the starting materials. Various techniques have been employed to achieve a controlled fluorination yield; however, the effect of contaminants is rarely discussed, although they are often present. In the present work, the fluorination of vertically aligned multiwalled carbon nanotubes was performed using plasma treatment in a magnetron sputtering chamber with fluorine diluted in an argon atmosphere with an Ar/F2 ratio of 95:5. The effect of heavily diluted fluorine in the precursor gas mixture is investigated by evaluating the modifications in the nanotube structure and the electronic properties upon plasma treatment. The existence of oxygen-based grafted species is associated with background oxygen species present in the plasma chamber in addition to fluorine. The thermal stability and desorption process of the fluorine species grafted on the carbon nanotubes during the fluorine plasma treatment were evaluated by combining different spectroscopic techniques.

  1. Magnetogravitational stability of resistive plasma through porous medium with thermal conduction and FLR corrections

    International Nuclear Information System (INIS)

    Vaghela, D.S.; Chhajlani, R.K.

    1989-01-01

    The problem of stability of self gravitating magnetized plasma in porous medium is studied incorporating electrical resistivity, thermal conduction and FLR corrections. Normal mode analysis is applied to derive the dispersion relation. Wave propagation is discussed for parallel and perpendicular directions to the magnetic field. Applying Routh Hurwitz Criterion the stability of the medium is discussed and it is found that Jeans' criterion determines the stability of the medium. Magnetic field, porosity and resistivity of the medium have no effect on Jeans' Criterion in longitudinal direction. For perpendicular direction, in case of resistive medium Jeans' expression remains unaffected by magnetic field but for perfectly conducting medium magnetic field modifies the Jeans' expression to show the stabilizing effect. Thermal conductivity affects the sonic mode by making the process isothermal instead of adiabatic. Porosity of the medium is effective only in case of perpendicular direction to magnetic field for perfectly conducting plasma as it reduces the stabilizing effect of magnetic field. For longitudinal wave propagation, though Finite Larmor Radius (FLR) corrections have no effect on sonic mode but it changes the growth rate for Alfven mode. For transverse wave propagation FLR corrections and porosity affect the Jeans' expression in case of non-viscous medium but viscosity of the medium removes the effect of FLR and porosity on Jeans' condition. (author)

  2. Formation of hydrophobic coating on glass surface using atmospheric pressure non-thermal plasma in ambient air

    International Nuclear Information System (INIS)

    Fang, Z; Qiu, Y; Kuffel, E

    2004-01-01

    Non-thermal plasmas under atmospheric pressure are of great interest in material surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of a glass surface for improving hydrophobicity using a non-thermal plasma generated by a dielectric barrier corona discharge (DBCD) with a needle array-to-plane electrode arrangement in atmospheric air is conducted, and the surface properties of the glass before and after the DBCD treatment are studied using contact angle measurement, surface resistance measurement and the wet flashover voltage test. The effects of the plasma dose (the product of average discharge power and treatment time) of DBCD on the surface modification are studied, and the mechanism of interaction between the plasma and glass surface is discussed. It is found that a layer of hydrophobic coating is formed on the glass surface through DBCD treatment, and the improvement of hydrophobicity depends on the plasma dose of the DBCD. It seems that there is an optimum plasma dose for the surface treatment. The test results of thermal ageing and chemical ageing show that the hydrophobic layer has quite stable characteristics

  3. The impact of transient thermal loads on beryllium as plasma facing material

    Energy Technology Data Exchange (ETDEWEB)

    Spilker, Benjamin Christof

    2017-01-24

    microstructural integrity in the transition region involves the risk of a macroscopic delamination of armour material, which reduces the lifetime of afflicted first wall panels. Overall, it was found that the yield strength and ultimate tensile strength of beryllium represent two key parameters that strongly influence its performance under transient thermal loading. Both quantities decrease as a function of the base temperature. Therefore, a lower base temperature (tested down to room temperature) is favourable for the performance of the beryllium armour tiles in ITER. The generated results indicate that the plastic deformation and the cracking of beryllium do not pose a threat to the operation of ITER, if the heat flux factors of the transient thermal pulses remain at 9 MW m{sup -2} s{sup 0.5} or below. This conclusion was drawn from the fact that the thermally induced damage saturated after 10{sup 5} pulses and did not significantly change for up to 10{sup 7} pulses. However, the performed experiments did not include the effects of plasma exposure and neutron irradiation of beryllium, though these loading conditions will be present in ITER in addition to the evaluated transient thermal loads. Further experiments with sequential and simultaneous plasma/thermal/neutron loading are proposed to investigate the synergistic effects of the different loading types and to evaluate possible shifts of the threshold values that were determined within this work.

  4. The impact of transient thermal loads on beryllium as plasma facing material

    International Nuclear Information System (INIS)

    Spilker, Benjamin Christof

    2017-01-01

    microstructural integrity in the transition region involves the risk of a macroscopic delamination of armour material, which reduces the lifetime of afflicted first wall panels. Overall, it was found that the yield strength and ultimate tensile strength of beryllium represent two key parameters that strongly influence its performance under transient thermal loading. Both quantities decrease as a function of the base temperature. Therefore, a lower base temperature (tested down to room temperature) is favourable for the performance of the beryllium armour tiles in ITER. The generated results indicate that the plastic deformation and the cracking of beryllium do not pose a threat to the operation of ITER, if the heat flux factors of the transient thermal pulses remain at 9 MW m"-"2 s"0"."5 or below. This conclusion was drawn from the fact that the thermally induced damage saturated after 10"5 pulses and did not significantly change for up to 10"7 pulses. However, the performed experiments did not include the effects of plasma exposure and neutron irradiation of beryllium, though these loading conditions will be present in ITER in addition to the evaluated transient thermal loads. Further experiments with sequential and simultaneous plasma/thermal/neutron loading are proposed to investigate the synergistic effects of the different loading types and to evaluate possible shifts of the threshold values that were determined within this work.

  5. Deposition stress effects on thermal barrier coating burner rig life

    Science.gov (United States)

    Watson, J. W.; Levine, S. R.

    1984-01-01

    A study of the effect of plasma spray processing parameters on the life of a two layer thermal barrier coating was conducted. The ceramic layer was plasma sprayed at plasma arc currents of 900 and 600 amps onto uncooled tubes, cooled tubes, and solid bars of Waspalloy in a lathe with 1 or 8 passes of the plasma gun. These processing changes affected the residual stress state of the coating. When the specimens were tested in a Mach 0.3 cyclic burner rig at 1130 deg C, a wide range of coating lives resulted. Processing factors which reduced the residual stress state in the coating, such as reduced plasma temperature and increased heat dissipation, significantly increased coating life.

  6. Performance evaluation of non-thermal plasma on particulate matter, ozone and CO2 correlation for diesel exhaust emission reduction

    DEFF Research Database (Denmark)

    Babaie, Meisam; Davari, Pooya; Talebizadeh, Poyan

    2015-01-01

    This study is seeking to investigate the effect of non-thermal plasma technology in the abatement of particulate matter (PM) from the actual diesel exhaust. Ozone (O3) strongly promotes PM oxidation, the main product of which is carbon dioxide (CO2). PM oxidation into the less harmful product (CO2...

  7. Thermal radiation from an evolving viscous quark gluon plasma

    International Nuclear Information System (INIS)

    Mitra, Sukanya; Mohanty, Payal; Sarkar, Sourav; Alam, Jan-E

    2013-01-01

    The effects of viscosity on the space-time evolution of quark gluon plasma produced in nuclear collisions at relativistic heavy ion collider energies have been studied. The entropy generated due to the viscous motion of the fluid has been taken into account in constraining the initial temperature by the final multiplicity (measured at the freeze-out point). The viscous effects on the photon spectra has been introduced consistently through the evolution dynamics and phase space factors of all the participating partons/hadrons in the production process. In contrast to some of the recent calculations the present work includes the contribution from the hadronic phase. A small change in the transverse momentum (p T ) distribution of photons is observed due to viscous effects. (author)

  8. Modelling of ion thermal transport in ergodic region of collisionless toroidal plasma

    International Nuclear Information System (INIS)

    Kanno, Ryutaro; Nunami, Masanori; Satake, Shinsuke; Ohyabu, Nobuyoshi; Takamaru, Hisanori; Okamoto, Masao

    2009-09-01

    In recent tokamak experiments it has been found that so-called diffusion theory based on the 'diffusion of magnetic field lines' overestimates the radial energy transport in the ergodic region of the collisionless plasma affected by resonant magnetic perturbations (RMPs), though the RMPs induce chaotic behavior of the magnetic field lines. The result implies that the modelling of the transport should be reconsidered for low collisionality cases. A computer simulation study of transport in the ergodic region is required for understanding fundamental properties of collisionless ergodized-plasmas, estimating the transport coefficients, and reconstructing the modelling of the transport. In this paper, we report the simulation study of thermal transport in the ergodic region under the assumption of neglecting effects of an electric field, impurities and neutrals. Because of the simulations neglecting interactions with different particle-species and saving the computational time, we treat ions (protons) in our numerical-study of the transport. We find that the thermal diffusivity in the ergodic region is extremely small compared to the one predicted by the theory of field-line diffusion and that the diffusivity depends on both the collision frequency and the strength of RMPs even for the collisionless ergodized-plasma. (author)

  9. Synthesis of {gamma}-aluminium oxynitride spinel using thermal plasma technique

    Energy Technology Data Exchange (ETDEWEB)

    Panda, Pravuram; Singh, S. K.; Sinha, S. P. [School of Applied Science (Physics), KIIT University, Bhubaneswar 751024 (India); Advanced Materials Technology Department, IMMT (CSIR), Bhubaneswar 751013 (India); School of Applied Science (Physics), KIIT University, Bhubaneswar 751024 (India)

    2012-07-23

    The synthesis technique of {gamma}-AlON in NH{sub 3} plasma using extended arc thermal plasma reactor have been reported. Dense cubic AlON spinel was synthesized in liquid state by fusion of mixture of Al{sub 2}O{sub 3} and AlN powder under thermal plasma. The density of the fused AlON was found to be 3.64 g/cc which is 98.11% of theoretical value. The formation of AlON was confirmed from XRD and Raman studies. Well faceted structure of plasma fused AlON was observed in FE-SEM micrograph.

  10. The Quark-Gluon Plasma Collective Dynamics and Hard Thermal Loops

    CERN Document Server

    Blaizot, J P; Blaizot, Jean-Paul; Iancu, Edmond

    2002-01-01

    We present a unified description of the high temperature phase of QCD, the so-called quark-gluon plasma, in a regime where the effective gauge coupling $g$ is sufficiently small to allow for weak coupling calculations. The main focuss is the construction of the effective theory for the collective excitations which develop at a typical scale $gT$, which is well separated from the typical energy of single particle excitations which is the temperature $T$. We show that the plasma particles provide a source for long wavelength oscillations of average fields which carry the quantum numbers of the plasma constituents, the quarks and the gluons. To leading order in $g$, the plasma particles obey simple gauge-covariant kinetic equations, whose derivation from the general Dyson-Schwinger equations is outlined. As a by-product, the ``hard thermal loops'' emerge naturally in a physically transparent framework. We show that the collective excitations can be described in terms of classical fields, and develop for these a ...

  11. Realization of thermally durable close-packed 2D gold nanoparticle arrays using self-assembly and plasma etching

    International Nuclear Information System (INIS)

    Sivaraman, Sankar K; Santhanam, Venugopal

    2012-01-01

    Realization of thermally and chemically durable, ordered gold nanostructures using bottom-up self-assembly techniques are essential for applications in a wide range of areas including catalysis, energy generation, and sensing. Herein, we describe a modular process for realizing uniform arrays of gold nanoparticles, with interparticle spacings of 2 nm and above, by using RF plasma etching to remove ligands from self-assembled arrays of ligand-coated gold nanoparticles. Both nanoscale imaging and macroscale spectroscopic characterization techniques were used to determine the optimal conditions for plasma etching, namely RF power, operating pressure, duration of treatment, and type of gas. We then studied the effect of nanoparticle size, interparticle spacing, and type of substrate on the thermal durability of plasma-treated and untreated nanoparticle arrays. Plasma-treated arrays showed enhanced chemical and thermal durability, on account of the removal of ligands. To illustrate the application potential of the developed process, robust SERS (surface-enhanced Raman scattering) substrates were formed using plasma-treated arrays of silver-coated gold nanoparticles that had a silicon wafer or photopaper as the underlying support. The measured value of the average SERS enhancement factor (2 × 10 5 ) was quantitatively reproducible on both silicon and paper substrates. The silicon substrates gave quantitatively reproducible results even after thermal annealing. The paper-based SERS substrate was also used to swab and detect probe molecules deposited on a solid surface. (paper)

  12. Magnetic pressure effects in a plasma-liner interface

    Science.gov (United States)

    García-Rubio, F.; Sanz, J.

    2018-04-01

    A theoretical analysis of magnetic pressure effects in a magnetized liner inertial fusion-like plasma is presented. In previous publications [F. García-Rubio and J. Sanz, Phys. Plasmas 24, 072710 (2017)], the evolution of a hot magnetized plasma in contact with a cold unmagnetized plasma, aiming to represent the hot spot and liner, respectively, was investigated in planar geometry. The analysis was made in a double limit low Mach and high thermal to magnetic pressure ratio β. In this paper, the analysis is extended to an arbitrary pressure ratio. Nernst, Ettingshausen, and Joule effects come into play in the energy balance. The region close to the liner is governed by thermal conduction, while the Joule dissipation becomes predominant far from it when the pressure ratio is low. Mass ablation, thermal energy, and magnetic flux losses are reduced with plasma magnetization, characterized by the electron Hall parameter ω e τ e , until β values of order unity are reached. From this point forward, increasing the electron Hall parameter no longer improves the magnetic flux conservation, and mass ablation is enhanced due to the magnetic pressure gradients. A thoughtful simplification of the problem that allows to reduce the order of the system of governing equations while still retaining the finite β effects is presented and compared to the exact case.

  13. Theory of dielectronic recombination and plasma effects

    International Nuclear Information System (INIS)

    Yukap Hahn

    2000-01-01

    Current status of the various theoretical approaches to calculation of dielectronic recombination rates is summarized, with emphasis on the available data base and on the plasma effects of both the plasma ion (and external) fields and plasma electron collisional effects which seriously affect the rates and complicate compilation of data. (author)

  14. Non-thermal plasma ethanol reforming in bubbles immersed in liquids

    International Nuclear Information System (INIS)

    Levko, Dmitry; Sharma, Ashish; Raja, Laxminarayan L

    2017-01-01

    Ethanol reforming in non-thermal plasma generated in atmospheric-pressure argon bubbles immersed in liquid ethanol/water solution is studied using a self-consistent multi-species fluid model. The influence of the dielectric constant of the liquid on the plasma dynamics and its effect on the generation of active species is analyzed. Several modes of discharge are obtained for large liquid dielectric constant. In these modes, we obtain either an axial streamer or a combination of two simultaneous streamers propagating along the bubble axis and near the liquid wall. The influence of these modes on the production of active species is also studied. The main reactions responsible for the generation of molecular hydrogen and light hydrocarbon species are analyzed. A possible mechanism of hydrogen generation in liquid phase is discussed. (paper)

  15. Microstructural modifications induced by rapid thermal annealing in plasma deposited SiOxNyHz films

    International Nuclear Information System (INIS)

    Prado, A. del; San Andres, E.; Martil, I.; Gonzalez-Diaz, G.; Bravo, D.; Lopez, F.J.; Fernandez, M.; Martinez, F.L.

    2003-01-01

    The effect of rapid thermal annealing (RTA) processes on the structural properties of SiO x N y H z films was investigated. The samples were deposited by the electron cyclotron resonance plasma method, using SiH 4 , O 2 and N 2 as precursor gases. For SiO x N y H z films with composition close to that of SiO 2 , which have a very low H content, RTA induces thermal relaxation of the lattice and improvement of the structural order. For films of intermediate composition and of compositions close to SiN y H z , the main effect of RTA is the release of H at high temperatures (T>700 deg. C). This H release is more significant in films containing both Si-H and N-H bonds, due to cooperative reactions between both kinds of bonds. In these films the degradation of structural order associated to H release prevails over thermal relaxation, while in those films with only N-H bonds, thermal relaxation predominates. For annealing temperatures in the 500-700 deg. C range, the passivation of dangling bonds by the nonbonded H in the films and the transition from the paramagnetic state to the diamagnetic state of the K center result in a decrease of the density of paramagnetic defects. The H release observed at high annealing temperatures is accompanied by an increase of density of paramagnetic defects

  16. Thermal structure of atmospheric pressure non-equilibrium plasmas

    International Nuclear Information System (INIS)

    Nozaki, Tomohiro; Unno, Yasuko; Okazaki, Ken

    2002-01-01

    The thermal structure of a methane-fed dielectric barrier discharge (DBD) and a atmospheric pressure glow-discharge (APG) has been extensively investigated in terms of time-averaged gas temperature profile between two parallel-plate electrodes separated by 1.0 mm. Emission spectroscopy of the rotational band of CH ((0, 0) A 2 Δ→X 2 Π:431 nm) was performed for this purpose. In order to minimize average temperature increase in the reaction field, DBD and APG were activated by 10 kHz with 2% duty cycle pulsed voltage (2 μs pulse width/100 μs interval). In DBD, temperature increase of a single microdischarge, on a time average, reached 200 K. It suddenly decreased below 100 K associated with the dark space formation near the dielectric barrier. Also, gas temperature in the surface discharge was fairly low because emission in these regions was limited within the initial stages of propagation (∼5 ns), whereas energy deposition would continue until microdischarge extinction; these facts implied that rotational temperature seemed to be far below the actual gas temperature in these regions. In APG, gas temperature was uniformly increased by positive column formation. In addition, a remarkable temperature increase due to negative glow formation was obtained only near the metallic electrode. For practical interest, we also investigated the net temperature increase with high frequency operations (AC-80 kHz), which depends not only on plasma properties, but also various engineering factors such as flow field, external cooling conditions, and total input power. In DBD, gas temperature in the middle of gas gap was significantly increased with increasing input power because of poor cooling conditions. In APG, in contrast, gas temperature near the electrodes was significantly increased associated with negative glow formation

  17. RACLETTE: a model for evaluating the thermal response of plasma facing components to slow high power plasma transients. Pt. II. Analysis of ITER plasma facing components

    International Nuclear Information System (INIS)

    Federici, G.; Raffray, A.R.

    1997-01-01

    For pt.I see ibid., p.85-100, 1997. The transient thermal model RACLETTE (acronym of Rate Analysis Code for pLasma Energy Transfer Transient Evaluation) described in part I of this paper is applied here to analyse the heat transfer and erosion effects of various slow (100 ms-10 s) high power energy transients on the actively cooled plasma facing components (PFCs) of the International Thermonuclear Experimental Reactor (ITER). These have a strong bearing on the PFC design and need careful analysis. The relevant parameters affecting the heat transfer during the plasma excursions are established. The temperature variation with time and space is evaluated together with the extent of vaporisation and melting (the latter only for metals) for the different candidate armour materials considered for the design (i.e., Be for the primary first wall, Be and CFCs for the limiter, Be, W, and CFCs for the divertor plates) and including for certain cases low-density vapour shielding effects. The critical heat flux, the change of the coolant parameters and the possible severe degradation of the coolant heat removal capability that could result under certain conditions during these transients, for example for the limiter, are also evaluated. Based on the results, the design implications on the heat removal performance and erosion damage of the various ITER PFCs are critically discussed and some recommendations are made for the selection of the most adequate protection materials and optimum armour thickness. (orig.)

  18. RACLETTE: a model for evaluating the thermal response of plasma facing components to slow high power plasma transients. Part II: Analysis of ITER plasma facing components

    Science.gov (United States)

    Federici, Gianfranco; Raffray, A. René

    1997-04-01

    The transient thermal model RACLETTE (acronym of Rate Analysis Code for pLasma Energy Transfer Transient Evaluation) described in part I of this paper is applied here to analyse the heat transfer and erosion effects of various slow (100 ms-10 s) high power energy transients on the actively cooled plasma facing components (PFCs) of the International Thermonuclear Experimental Reactor (ITER). These have a strong bearing on the PFC design and need careful analysis. The relevant parameters affecting the heat transfer during the plasma excursions are established. The temperature variation with time and space is evaluated together with the extent of vaporisation and melting (the latter only for metals) for the different candidate armour materials considered for the design (i.e., Be for the primary first wall, Be and CFCs for the limiter, Be, W, and CFCs for the divertor plates) and including for certain cases low-density vapour shielding effects. The critical heat flux, the change of the coolant parameters and the possible severe degradation of the coolant heat removal capability that could result under certain conditions during these transients, for example for the limiter, are also evaluated. Based on the results, the design implications on the heat removal performance and erosion damage of the variuos ITER PFCs are critically discussed and some recommendations are made for the selection of the most adequate protection materials and optimum armour thickness.

  19. RACLETTE: a model for evaluating the thermal response of plasma facing components to slow high power plasma transients. Part I: Theory and description of model capabilities

    Science.gov (United States)

    Raffray, A. René; Federici, Gianfranco

    1997-04-01

    RACLETTE (Rate Analysis Code for pLasma Energy Transfer Transient Evaluation), a comprehensive but relatively simple and versatile model, was developed to help in the design analysis of plasma facing components (PFCs) under 'slow' high power transients, such as those associated with plasma vertical displacement events. The model includes all the key surface heat transfer processes such as evaporation, melting, and radiation, and their interaction with the PFC block thermal response and the coolant behaviour. This paper represents part I of two sister and complementary papers. It covers the model description, calibration and validation, and presents a number of parametric analyses shedding light on and identifying trends in the PFC armour block response to high plasma energy deposition transients. Parameters investigated include the plasma energy density and deposition time, the armour thickness and the presence of vapour shielding effects. Part II of the paper focuses on specific design analyses of ITER plasma facing components (divertor, limiter, primary first wall and baffle), including improvements in the thermal-hydraulic modeling required for better understanding the consequences of high energy deposition transients in particular for the ITER limiter case.

  20. RACLETTE: a model for evaluating the thermal response of plasma facing components to slow high power plasma transients. Pt. I. Theory and description of model capabilities

    International Nuclear Information System (INIS)

    Raffray, A.R.; Federici, G.

    1997-01-01

    For pt.II see ibid., p.101-30, 1997. RACLETTE (Rate Analysis Code for pLasma Energy Transfer Transient Evaluation), a comprehensive but relatively simple and versatile model, was developed to help in the design analysis of plasma facing components (PFCs) under 'slow' high power transients, such as those associated with plasma vertical displacement events. The model includes all the key surface heat transfer processes such as evaporation, melting, and radiation, and their interaction with the PFC block thermal response and the coolant behaviour. This paper represents part I of two sister and complementary papers. It covers the model description, calibration and validation, and presents a number of parametric analyses shedding light on and identifying trends in the PFC armour block response to high plasma energy deposition transients. Parameters investigated include the plasma energy density and deposition time, the armour thickness and the presence of vapour shielding effects. Part II of the paper focuses on specific design analyses of ITER plasma facing components (divertor, limiter, primary first wall and baffle), including improvements in the thermal-hydraulic modeling required for better understanding the consequences of high energy deposition transients in particular for the ITER limiter case. (orig.)

  1. Thermal plasma synthesis of Fe1−xNix alloy nanoparticles

    International Nuclear Information System (INIS)

    Raut, Suyog A.; Kanhe, Nilesh S.; Bhoraskar, S. V.; Mathe, V. L.; Das, A. K.

    2014-01-01

    Fe-Ni alloy nanoparticles are of great interest because of diverse practical applications in the fields such as magnetic fluids, high density recording media, catalysis and medicine. We report the synthesis of Fe-Ni nanoparticles via thermal plasma route. Thermal plasma assisted synthesis is a high temperature process and gives high yields of production. Here, we have used direct arc thermal plasma plume of 6kw as a source of energy at operating pressure 500 Torr. The mixture of Fe-Ni powder in required proportion (Fe 1−x Ni x ; x=0.30, 0.32, 0.34, 0.36, 0.38 and 0.40) was made to evaporate simultaneously from the graphite anode in thermal plasma reactor to form Fe-Ni bimetallic nanoparticles. The as synthesized particles were characterized by X-Ray Diffraction (XRD), Thermo-Gravimetric Analysis/Differential Scanning Calorimtry (TGA/DSC)

  2. Complementary variational principle method applied to thermal conductivities of a plasma in a uniform magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Sehgal, A K; Gupta, S C [Punjabi Univ., Patiala (India). Dept. of Physics

    1982-12-14

    The complementary variational principles method (CVP) is applied to the thermal conductivities of a plasma in a uniform magnetic field. The results of computations show that the CVP derived results are very useful.

  3. Improved oxidation of air pollutants in a non-thermal plasma

    International Nuclear Information System (INIS)

    Roland, U.; Holzer, F.; Kopinke, F.-D.

    2002-01-01

    The performance of non-thermal plasma (NTP) for the removal of organic air pollutants (especially in low concentrations) is improved by the introduction of ferroelectric and catalytically active materials into the discharge zone of an NTP reactor. Experiments with model systems (various contaminants and packed-bed materials) have shown that such a modification of a homogeneous gas-phase plasma can overcome the most serious restrictions of the NTP technique at its present state of the art: the incomplete total oxidation (i.e. the low selectivity to CO 2 ) and the energetic inefficiency. Placing a ferroelectric packed-bed material in the discharge zone was shown to result in a lowering of the energy input required. The main effects of plasma catalysis enabled by the introduction of a catalytically active material were an enhanced conversion of pollutants and a higher CO 2 selectivity. These improvements are based on the presence of short-lived oxidising species in the inner volume of porous catalysts. Additionally, the formation of a reservoir of adsorbed oxidants in the NTP zone could be shown. The combination of both modifications (ferroelectric packed-bed materials and plasma catalysis) is a promising method to support the NTP-initiated oxidation of air pollutants

  4. A universal mirror wave-mode threshold condition for non-thermal space plasma environments

    Directory of Open Access Journals (Sweden)

    M. P. Leubner

    2002-01-01

    Full Text Available Magnetic fluctuations are recognized in a large variety of space plasmas by increasingly high resolution, in situ observations as mirror wave mode structures. A typical requirement for the excitation of mirror modes is a dominant perpendicular pressure in a high-beta plasma environment. Contrary, we demonstrate from a realistic kinetic analysis how details of the velocity space distributions are of considerable significance for the instability threshold. Introducing the most common characteristics of observed ion and electron distributions by a mixed suprathermal-loss-cone, we derive a universal mirror instability criterion from an energy principle for collisionless plasmas. As a result, the transition from two temperature Maxwellians to realistic non-thermal features provides a strong source for the generation of mirror wave mode activity, reducing drastically the instability threshold. In particular, a number of space-related examples illuminate how the specific structure of the velocity space distribution dominates as a regulating excitation mechanism over the effects related to changes in the plasma parameters.

  5. Improvement of Polytetrafluoroethylene Surface Energy by Repetitive Pulse Non-Thermal Plasma Treatment in Atmospheric Air

    International Nuclear Information System (INIS)

    Yang Guoqing; Zhang Guanjun; Zhang Wenyuan

    2011-01-01

    Improvement of polytetrafluoroethylene surface energy by non-thermal plasma treatment is presented, using a nanosecond-positive-edge repetitive pulsed dielectric barrier discharge generator in atmospheric air. The electrical parameters including discharging power, peak and density of micro-discharge current were calculated, and the electron energy was estimated. Surface treatment experiments of polytetrafluoroethylene films were conducted for both different applied voltages and different treating durations. Results show that the surface energy of polytetrafluoroethylene film could be improved to 40 mJ/m 2 or more by plasma treatment. Surface roughness measurement and surface X-ray photoelectron spectroscopy analysis indicate that there are chemical etching and implantation of polar oxygen groups in the sample surface treating process, resulting in the improvement of the sample surface energy. Compared with an AC source of 50 Hz, the dielectric barrier discharges generated by a repetitive pulsed source could provide higher peak power, lower mean power, larger micro-discharge current density and higher electron energy. Therefore, with the same applied peak voltage and treating duration, the improvement of polytetrafluoroethylene surface energy using repetitive pulsed plasma is more effective, and the plasma treatment process based on repetitive pulsed dielectric barrier discharges in air is thus feasible and applicable.

  6. Hyper-resistivity and electron thermal conductivity due to destroyed magnetic surfaces in axisymmetric plasma equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Weening, R. H. [Department of Radiologic Sciences, Thomas Jefferson University, 901 Walnut Street, Philadelphia, Pennsylvania 19107-5233 (United States)

    2012-06-15

    In order to model the effects of small-scale current-driven magnetic fluctuations in a mean-field theoretical description of a large-scale plasma magnetic field B(x,t), a space and time dependent hyper-resistivity {Lambda}(x,t) can be incorporated into the Ohm's law for the parallel electric field E Dot-Operator B. Using Boozer coordinates, a theoretical method is presented that allows for a determination of the hyper-resistivity {Lambda}({psi}) functional dependence on the toroidal magnetic flux {psi} for arbitrary experimental steady-state Grad-Shafranov axisymmetric plasma equilibria, if values are given for the parallel plasma resistivity {eta}({psi}) and the local distribution of any auxiliary plasma current. Heat transport in regions of plasma magnetic surfaces destroyed by resistive tearing modes can then be modeled by an electron thermal conductivity k{sub e}({psi})=({epsilon}{sub 0}{sup 2}m{sub e}/e{sup 2}){Lambda}({psi}), where e and m{sub e} are the electron charge and mass, respectively, while {epsilon}{sub 0} is the permittivity of free space. An important result obtained for axisymmetric plasma equilibria is that the {psi}{psi}-component of the metric tensor of Boozer coordinates is given by the relation g{sup {psi}{psi}}({psi}){identical_to}{nabla}{psi} Dot-Operator {nabla}{psi}=[{mu}{sub 0}G({psi})][{mu}{sub 0}I({psi})]/{iota}({psi}), with {mu}{sub 0} the permeability of free space, G({psi}) the poloidal current outside a magnetic surface, I({psi}) the toroidal current inside a magnetic surface, and {iota}({psi}) the rotational transform.

  7. The thermal response of the first wall of a fusion reactor blanket to plasma disruptions

    International Nuclear Information System (INIS)

    Klippel, H.Th.

    1983-09-01

    Major plasma disruptions in Tokamak power reactors are potentially dangerous because high thermal overloading of the first wall may occur, resulting in melting and evaporation. The present uncertainties of the disruption characteristics, in particular the space and time dependence of the energy deposition, lead to a wide variation in the prospective surface energy loads. The thermal response of a first wall of aluminium, stainless steel and of graphite subjected to disruption energy loads up to 1000 J cm -2 has been analysed including the effects of melting and surface evaporation, vapour recondensation, vapour shielding, and the moving of the surface boundary caused by the evaporation. A special calculation model has been developed for this purpose. The main results are the following: by values of local transient energy depositions over 1500 J cm -2 bare stainless steel walls are damaged severely. Further calculations are needed to estimate the endurance limit of several candidate first wall materials. Applications of coatings on surfaces need special attention. For the reference INTOR disruption (approx. 100 J cm -2 ) evaporation is not significant. The effect of vapour shielding on evaporation has been found to be significant. The effect on melting is less pronounced. In a complete analysis the stability and dynamic behaviour of the melted layer under electromagnetic forces should be included. Also a reliable set of plasma disruption characteristics should be gathered

  8. Thermal effects in radiation processing

    International Nuclear Information System (INIS)

    Zagorski, Z.P.

    1985-01-01

    The balance of ionizing radiation energy incident on an object being processed is discussed in terms of energy losses, influencing the amount really absorbed. To obtain the amount of heat produced, the absorbed energy is corrected for the change in internal energy of the system and for the heat effect of secondary reactions developing after the initiation. The temperature of a processed object results from the heat evolved and from the specific heat of the material comprising the object. The csub(p) of most materials is usually much lower than that of aqueous systems and therefore temperatures after irradiation are higher. The role of low specific heat in radiation processing at cryogenic conditions is stressed. Adiabatic conditions of accelerator irradiation are contrasted with the steady state thermal conditions prevailing in large gamma sources. Among specific questions discussed in the last part of the paper are: intermediate and final temperature of composite materials, measurement of real thermal effects in situ, neutralization of undesired warming experienced during radiation processing, processing at temperatures other than ambient and administration of very high doses of radiation. (author)

  9. Thermal effects in radiation processing

    International Nuclear Information System (INIS)

    Zagorski, Z.P.

    1984-01-01

    The balance of ionizing radiation energy incident on an object being processed is discussed in terms of energy losses, influencing the amount really absorbed. To obtain the amount of heat produced, the absorbed energy is corrected for the change in internal energy of the system and for the heat effect of secondary reactions developing after the initiation. The temperature of a processed object results from the heat evolved and from the specific heat of the material comprising the object. The specific heat of most materials is usually much lower than that of aqueous systems and therefore temperatures after irradiation are higher. The role of low specific heat in radiation processing at cryogenic conditions is stressed. Adiabatic conditions of accelerator irradiation are contrasted with the steady state thermal conditions prevailing in large gamma sources. Among specific questions discussed in the last part of the paper are: intermediate and final temperature of composite materials, measurement of real thermal effects in situ, neutralization of undesired warming experienced during radiation processing, processing at temperatures other than ambient and administration of very high doses of radiation

  10. Plasma diagnostic techniques in thermal-barrier tandem-mirror fusion experiments

    International Nuclear Information System (INIS)

    Silver, E.H.; Clauser, J.F.; Carter, M.R.; Failor, B.H.; Foote, J.H.; Hornady, R.S.; James, R.A.; Lasnier, C.J.; Perkins, D.E.

    1986-01-01

    We review two classes of plasma diagnostic techniques used in thermal-barrier tandem-mirror fusion experiments. The emphasis of the first class is to study mirror-trapped electrons at the thermal-barrier location. The focus of the second class is to measure the spatial and temporal behavior of the plasma space potential at various axial locations. The design and operation of the instruments in these two categories are discussed and data that are representative of their performance is presented

  11. Dentin surface treatment using a non-thermal argon plasma brush for interfacial bonding improvement in composite restoration

    Science.gov (United States)

    Ritts, Andy Charles; Li, Hao; Yu, Qingsong; Xu, Changqi; Yao, Xiaomei; Hong, Liang; Wang, Yong

    2010-01-01

    The objective of this study is to investigate the treatment effects of non-thermal atmospheric gas plasmas on dentin surfaces for composite restoration. Extracted unerupted human third molars were used by removing the crowns and etching the exposed dentin surfaces with 35% phosphoric acid gel. The dentin surfaces were treated by using a non-thermal atmospheric argon plasma brush for various durations. The molecular changes of the dentin surfaces were analyzed using FTIR/ATR and an increase in carbonyl groups on dentin surfaces was detected with plasma treated dentin. Adper Single Bond Plus adhesive and Filtek Z250 dental composite were applied as directed. To evaluate the dentin/composite interfacial bonding, the teeth thus prepared were sectioned into micro-bars as the specimens for tensile test. Student Newman Keuls tests showed that the bonding strength of the composite restoration to peripheral dentin was significantly increased (by 64%) after 30 s plasma treatment. However, the bonding strength to plasma treated inner dentin did not show any improvement. It was found that plasma treatment of peripheral dentin surface up to 100 s gave an increase in interfacial bonding strength, while a prolong plasma treatment of dentin surfaces, e.g., 5 min treatments, showed a decrease in interfacial bonding strength. PMID:20831586

  12. Thermal equilibrium of pure electron plasmas across a central region of magnetic surfaces

    Science.gov (United States)

    Hahn, Michael; Pedersen, Thomas Sunn

    2009-06-01

    Measurements of the equilibria of plasmas created by emission from a biased filament located off the magnetic axis in the Columbia Non-neutral Torus (CNT) [T. S. Pedersen, J. P. Kremer, R. G. Lefrancois et al., Fusion Sci. Technol. 50, 372 (2006)] show that such plasmas have equilibrium properties consistent with the inner surfaces being in a state of cross-surface thermal equilibrium. Numerical solutions to the equilibrium equation were used to fit the experimental data and demonstrate consistency with cross-surface thermal equilibrium. Previous experiments in CNT showed that constant temperatures across magnetic surfaces are characteristic of CNT plasmas, implying thermal confinement times much less than particle confinement times. These results show that when emitting off axis there is a volume of inner surfaces where diffusion into that region is balanced by outward transport, producing a Boltzmann distribution of electrons. When combined with the low thermal energy confinement time this is a cross-surface thermal equilibrium.

  13. Thermal equilibrium of pure electron plasmas across a central region of magnetic surfaces

    International Nuclear Information System (INIS)

    Hahn, Michael; Pedersen, Thomas Sunn

    2009-01-01

    Measurements of the equilibria of plasmas created by emission from a biased filament located off the magnetic axis in the Columbia Non-neutral Torus (CNT) [T. S. Pedersen, J. P. Kremer, R. G. Lefrancois et al., Fusion Sci. Technol. 50, 372 (2006)] show that such plasmas have equilibrium properties consistent with the inner surfaces being in a state of cross-surface thermal equilibrium. Numerical solutions to the equilibrium equation were used to fit the experimental data and demonstrate consistency with cross-surface thermal equilibrium. Previous experiments in CNT showed that constant temperatures across magnetic surfaces are characteristic of CNT plasmas, implying thermal confinement times much less than particle confinement times. These results show that when emitting off axis there is a volume of inner surfaces where diffusion into that region is balanced by outward transport, producing a Boltzmann distribution of electrons. When combined with the low thermal energy confinement time this is a cross-surface thermal equilibrium.

  14. Study of the thermal and suprathermal electron density fluctuations of the plasma in the Focus experiment

    International Nuclear Information System (INIS)

    Jolas, A.

    1981-10-01

    An experiment on Thomson scattering of ruby laser light by the electrons of a plasma produced by an intense discharge between the electrodes of a coaxial gun in a gas at low pressure has been carried out. It is shown that the imploding plasma is made up of layers with different characteristics: a dense plasma layer where the density fluctuations are isotropic and have a thermal level, and a tenuous plasma layer where the fluctuations are anisotropic, and strongly suprathermal. The suprathermal fluctuations are attributed to microscopic instabilities generated by the electric current circulating in the transition zone where the magnetic field penetrates the plasma [fr

  15. Intermittent thermal plasma acceleration linked to sporadic motions of the magnetopause, first Cluster results

    Directory of Open Access Journals (Sweden)

    J.-A. Sauvaud

    Full Text Available This paper presents the first observations with Cluster of a very dense population of thermal ionospheric ions (H+, He+, O+ locally "accelerated" perpendicularly to the local magnetic field in a region adjacent to the magnetopause and on its magnetospheric side. The observation periods follow a long period of very weak magnetic activity. Recurrent motions of the magnetopause are, in the presented cases, unexpectedly associated with the appearance inside closed field lines of recurrent energy structures of ionospheric ions with energies in the 5 eV to  ~1000 eV range. The heaviest ions were detected with the highest energies. Here, the ion behaviour is interpreted as resulting from local electric field enhancements/decreases which adiabatically enhance/lower the bulk energy of a local dense thermal ion population. This drift effect, which is directly linked to magnetopause motions caused by pressure changes, allows for the thermal ions to overcome the satellite potential and be detected by the suprathermal CIS Cluster experiment. When fast flowing, i.e. when detectable, the density (~ 1 cm-3 of these ions from a terrestrial origin is (in the cases presented here largely higher than the local density of ions from magnetospheric/plasma sheet origin which poses again the question of the relative importance of solar and ionospheric sources for the magnetospheric plasma even during very quiet magnetic conditions.

    Key words. Ionosphere (planetary ionosphere; plasma convection Magnetospheric physics (magnetopause, cusp and boundary layers

  16. Application of the thermal plasma technique in the treatment of stone surfaces

    International Nuclear Information System (INIS)

    Gonzalez A, Z.I.

    2000-01-01

    The stone materials which form part of the cultural heritage of Mexico, are degraded under the united action of water, atmospheric gases, air pollution, temperature changes and the microorganisms action; provoking on the stone: fissures, crevices, scalings, fragmentations, pulverizations, etc. Therefore, the purpose of this work is to study the possibilities to apply a protective coating on the stone surfaces, previously clean and consolidated, through the thermal plasma technique. The purpose is to analyse the physical and chemical properties of three types of stone materials: quarry, tezontle and chiluca, usually used in constructions of cultural interest such as: historical monuments, churches, sculptures, etc., before and after to be submitted to the action of thermal plasma in order to examine the feasibility in the use of this coating technique in this type of applications. The application of conventional techniques to determine: porosity, density, absorption, low pressure water absorption and crystallization by total immersion of nuclear techniques such as: neutron activation analysis, x-ray diffraction and scanning electron microscopy as well as of instrumental techniques: optical microscopy, mechanical assays of compression, flexure and surface area calculations, allowed to know the chemical and physical properties of the stone material before and after to be treated through the thermal plasma technique, projecting quartz on the stones surface at different distances and current intensity and showing the effect caused by the modifications or surface alterations present by cause of the application of that coating. the obtained results provide a general panorama of the application of this technique as an alternative to the maintenance of the architectural inheritance built in stone. (Author)

  17. Transition Region Emission and the Energy Input to Thermal Plasma in Solar Flares

    Science.gov (United States)

    Holman, Gordon D.; Holman, Gordon D.; Dennis, Brian R.; Haga, Leah; Raymond, John C.; Panasyuk, Alexander

    2005-01-01

    Understanding the energetics of solar flares depends on obtaining reliable determinations of the energy input to flare plasma. X-ray observations of the thermal bremsstrahlung from hot flare plasma provide temperatures and emission measures which, along with estimates of the plasma volume, allow the energy content of this hot plasma to be computed. However, if thermal energy losses are significant or if significant energy goes directly into cooler plasma, this is only a lower limit on the total energy injected into thermal plasma during the flare. We use SOHO UVCS observations of O VI flare emission scattered by coronal O VI ions to deduce the flare emission at transition region temperatures between 100,000 K and 1 MK for the 2002 July 23 and other flares. We find that the radiated energy at these temperatures significantly increases the deduced energy input to the thermal plasma, but by an amount that is less than the uncertainty in the computed energies. Comparisons of computed thermal and nonthermal electron energies deduced from RHESSI, GOES, and UVCS are shown.

  18. Thermal Plasma Synthesis of Crystalline Gallium Nitride Nanopowder from Gallium Nitrate Hydrate and Melamine

    Directory of Open Access Journals (Sweden)

    Tae-Hee Kim

    2016-02-01

    Full Text Available Gallium nitride (GaN nanopowder used as a blue fluorescent material was synthesized by using a direct current (DC non-transferred arc plasma. Gallium nitrate hydrate (Ga(NO33∙xH2O was used as a raw material and NH3 gas was used as a nitridation source. Additionally, melamine (C3H6N6 powder was injected into the plasma flame to prevent the oxidation of gallium to gallium oxide (Ga2O3. Argon thermal plasma was applied to synthesize GaN nanopowder. The synthesized GaN nanopowder by thermal plasma has low crystallinity and purity. It was improved to relatively high crystallinity and purity by annealing. The crystallinity is enhanced by the thermal treatment and the purity was increased by the elimination of residual C3H6N6. The combined process of thermal plasma and annealing was appropriate for synthesizing crystalline GaN nanopowder. The annealing process after the plasma synthesis of GaN nanopowder eliminated residual contamination and enhanced the crystallinity of GaN nanopowder. As a result, crystalline GaN nanopowder which has an average particle size of 30 nm was synthesized by the combination of thermal plasma treatment and annealing.

  19. Thermal effects on beryllium mirrors

    International Nuclear Information System (INIS)

    Weinswig, S.

    1989-01-01

    Beryllium is probably the most frequently used material for spaceborne system scan mirrors. Beryllium's properties include lightweightedness, high Young's modulus, high stiffness value, high resonance value. As an optical surface, beryllium is usually nickel plated in order to produce a higher quality surface. This process leads to the beryllium mirror acting like a bimetallic device. The mirror's deformation due to the bimetallic property can possibly degrade the performance of the associated optical system. As large space borne systems are designed and as temperature considerations become more crucial in the instruments, the concern about temporal deformation of the scan mirrors becomes a prime consideration. Therefore, two sets of tests have been conducted in order to ascertain the thermal effects on nickel plated beryllium mirrors. These tests are categorized. The purpose of this paper is to present the values of the bimetallic effect on typical nickel plated beryllium mirrors

  20. THERMODYNAMIC REASONS OF AGGLOMERATION OF DUST PARTICLES IN THE THERMAL DUSTY PLASMA

    Directory of Open Access Journals (Sweden)

    V.I.Vishnyakov

    2003-01-01

    Full Text Available The thermodynamic equilibrium of thermal dusty plasmas consisting of ionized gas (plasma and solid particles (dust grains, which interact with each other, is studied. The tendency of grains in dusty plasmas to agglomerate corresponds to the tendency of dusty plasmas to balanced states. When grains agglomerate, electrical perturbations generated by each grain concentrate inside the agglomerate. The plasma is perturbed only by the agglomerate's exterior surface. The greater number of possible states for electrons and ions in plasma depends on the volume of perturbation of grains. The fewer are the perturbations the greater is the amount of possible states for electrons and ions in plasma. If the grains collected from a distance smaller than 8 Debye lengths, the total volume of perturbations is minimized; the free energy of the plasma is also minimized.

  1. Development of innovative thermal plasma and particle diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Bachmann, Benjamin-Leon

    2013-09-24

    Three original plasma diagnostic systems have been developed to investigate transient three-dimensional plasma processes with high spatial and temporal resolution. The developed diagnostics have been analyzed and tested by increasing the complexity from a stationary free burning Argon arc to a dc pulsed process and finally to a transient gas metal arc including droplet transfer through the plasma. The transient plasma parameters that have been determined include three-dimensional axially symmetric plasma densities (n{sub e}, n{sub A}, n{sub A+}, n{sub A++}), electron temperatures (T{sub e}), electrical conductivities (σ{sub el}), magnetic flux densities (B) and current densities (j{sub el}). In the case of a droplet transfer through an arc consisting of an Iron/Argon plasma, the droplet density, surface tension, viscosity, and temperature have been determined.

  2. Analysis of the expanding thermal argon-oxygen plasma gas phase

    NARCIS (Netherlands)

    Hest, van M.F.A.M.; Haartsen, J.R.; Weert, van M.H.M.; Schram, D.C.; Sanden, van de M.C.M.

    2003-01-01

    An expanding thermal argon plasma into which oxygen is injected has been analyzed by means of Langmuir and Pitot probe measurements. Information is obtained on the ion d. profile and the flow pattern in the downstream plasma. A combination of Langmuir and Pitot probe measurements provide information

  3. Investigations of a thermal plasma jet structure by generalized correlation dimension

    Czech Academy of Sciences Publication Activity Database

    Gruber, Jan; Hlína, Jan; Šonský, Jiří

    2013-01-01

    Roč. 46, č. 1 (2013), s. 1-8 ISSN 0022-3727 Institutional research plan: CEZ:AV0Z20570509 Keywords : correlation dimension * turbulence * thermal plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.521, year: 2013

  4. Time-resolved tomographic measurements of temperatures in a thermal plasma jet

    Czech Academy of Sciences Publication Activity Database

    Hlína, Jan; Šonský, Jiří

    2010-01-01

    Roč. 43, č. 5 (2010), s. 1-9 ISSN 0022-3727 Institutional research plan: CEZ:AV0Z20570509 Keywords : thermal plasma jet * optical diagnostics * temperature distribution Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.105, year: 2010

  5. Dielectric effects on Thomson scattering in a relativistic magnetized plasma

    DEFF Research Database (Denmark)

    Bindslev, H.

    1991-01-01

    The effects of the dielectric properties of a relativistic magnetized plasma on the scattering of electromagnetic radiation by fluctuations in electron density are investigated. The origin of the density fluctuations is not considered. Expressions for the scattering cross-section and the scattered...... power accepted by the receiving antenna are derived for a plasma with spatial dispersion. The resulting expressions allow thermal motion to be included in the description of the plasma and remain valid for frequencies of the probing radiation in the region of omega(p) and omega(ce), provided...... the absorption is small. Symmetry between variables relating to incident and scattered fields is demonstrated and shown to be in agreement with the reciprocity relation. Earlier results are confirmed in the cold plasma limit. Significant relativistic effects, of practical importance to the scattering...

  6. Isotope effect on confinement in DT plasmas

    International Nuclear Information System (INIS)

    Fukuyama, A.; Itoh, K.; Itoh, S.; Yagi, M.; Azumi, M.

    1994-03-01

    Isotope effect on the energy confinement time is discussed for the DT plasma. The transport theory which is based on the ballooning mode turbulence is applied. When the DT plasma is produced under the condition of β p >1, the energy confinement time of DT plasma (50% mixture) is expected to be about 1.2 times better than the D plasma with the same operation condition. (author)

  7. Microstructural evolution and growth kinetics of thermally grown oxides in plasma sprayed thermal barrier coatings

    Directory of Open Access Journals (Sweden)

    Xiaoju Liu

    2016-02-01

    Full Text Available The formation of thermally grown oxide (TGO during high temperature is a key factor to the degradation of thermal barrier coatings (TBCs applied on hot section components. In the present study both the CoNiCrAlY bond coat and ZrO2-8 wt.% Y2O3 (8YSZ ceramic coat of TBCs were prepared by air plasma spraying (APS. The composition and microstructure of TGO in TBCs were investigated using scanning electron microscopy (SEM, energy dispersive spectroscopy (EDS and X-ray diffraction (XRD analysis. The growth rate of TGO for TBC and pure BC were gained after isothermal oxidation at 1100 °C for various times. The results showed that as-sprayed bond coat consisted of β and γ/γ′phases, β phase reducesd as the oxidation time increased. The TGO comprised α-Al2O3 formed in the first 2 h. CoO, NiO, Cr2O3 and spinel oxides appeared after 20 h of oxidation. Contents of CoO and NiO reduced while that of Cr2O3 and spinel oxides increased in the later oxidation stage. The TGO eventually consisted of a sub-Al2O3 layer with columnar microstructure and the upper porous CS clusters. The TGO growth kinetics for two kinds of samples followed parabolic laws, with oxidation rate constant of 0.344 μm/h0.5 for TBCs and 0.354 μm/h0.5 for pure BCs.

  8. Electrical conductivity of the thermal dusty plasma under the conditions of a hybrid plasma environment simulation facility

    Science.gov (United States)

    Zhukhovitskii, Dmitry I.; Petrov, Oleg F.; Hyde, Truell W.; Herdrich, Georg; Laufer, Rene; Dropmann, Michael; Matthews, Lorin S.

    2015-05-01

    We discuss the inductively heated plasma generator (IPG) facility in application to the generation of the thermal dusty plasma formed by the positively charged dust particles and the electrons emitted by them. We develop a theoretical model for the calculation of plasma electrical conductivity under typical conditions of the IPG. We show that the electrical conductivity of dusty plasma is defined by collisions with the neutral gas molecules and by the electron number density. The latter is calculated in the approximations of an ideal and strongly coupled particle system and in the regime of weak and strong screening of the particle charge. The maximum attainable electron number density and corresponding maximum plasma electrical conductivity prove to be independent of the particle emissivity. Analysis of available experiments is performed, in particular, of our recent experiment with plasma formed by the combustion products of a propane-air mixture and the CeO2 particles injected into it. A good correlation between the theory and experimental data points to the adequacy of our approach. Our main conclusion is that a level of the electrical conductivity due to the thermal ionization of the dust particles is sufficiently high to compete with that of the potassium-doped plasmas.

  9. Man-made vitreous fiber produced from incinerator ash using the thermal plasma technique and application as reinforcement in concrete.

    Science.gov (United States)

    Yang, Sheng-Fu; Wang, To-Mai; Lee, Wen-Cheng; Sun, Kin-Seng; Tzeng, Chin-Ching

    2010-10-15

    This study proposes using thermal plasma technology to treat municipal solid waste incinerator ashes. A feasible fiberization method was developed and applied to produce man-made vitreous fiber (MMVF) from plasma vitrified slag. MMVF were obtained through directly blending the oxide melt stream with high velocity compressed air. The basic technological characteristics of MMVF, including morphology, diameter, shot content, length and chemical resistance, are described in this work. Laboratory experiments were conducted on the fiber-reinforced concrete. The effects of fibrous content on compressive strength and flexural strength are presented. The experimental results showed the proper additive of MMVF in concrete can enhance its mechanical properties. MMVF products produced from incinerator ashes treated with the thermal plasma technique have great potential for reinforcement in concrete. 2010 Elsevier B.V. All rights reserved.

  10. Binary collision rates of relativistic thermal plasmas. I Theoretical framework

    Science.gov (United States)

    Dermer, C. D.

    1985-01-01

    Binary collision rates for arbitrary scattering cross sections are derived in the case of a beam of particles interacting with a Maxwell-Boltzmann (MB) plasma, or in the case of two MB plasmas interacting at generally different temperatures. The expressions are valid for all beam energies and plasma temperatures, from the nonrelativistic to the extreme relativistic limits. The calculated quantities include the reaction rate, the energy exchange rate, and the average rate of change of the squared transverse momentum component of a monoenergetic particle beam as a result of scatterings with particles of a MB plasma. Results are specialized to elastic scattering processes, two-temperature reaction rates, or the cold plasma limit, reproducing previous work.

  11. Characterization of thermal plasmas by laser light scattering

    International Nuclear Information System (INIS)

    Snyder, S.C.; Lassahn, G.D.; Reynolds, L.D.; Fincke, J.R.

    1993-01-01

    Characterization of an atmospheric pressure free-burning arc discharge and a plasma jet by lineshape analysis of scattered laser light is described. Unlike emission spectroscopy, this technique provides direct measurement of plasma gas temperature, electron temperature and electron density without the assumption of local thermodynamic equilibrium (LTE). Plasma gas velocity can also be determined from the Doppler shift of the scattered laser light. Radial gas temperature, electron temperature and electron density profiles are presented for an atmospheric pressure argon free-burning arc discharge. These results show a significant departure from LTE in the arc column, contradicting results obtained from emission spectroscopy. Radial gas temperature and gas velocity profiles in the exit plane of a subsonic atmospheric pressure argon plasma jet are also presented. In this case, the results show the plasma jet is close to LTE in the center, but not in the fringes. The velocity profile is parabolic

  12. Numerical study of divertor plasma transport with thermal force due to temperature gradient

    International Nuclear Information System (INIS)

    Ohtsu, Shigeki; Tanaka, Satoru; Yamawaki, Michio

    1992-01-01

    A one-dimensional, steady state divertor plasma model is developed in order to study the carbon impurity transport phenomena considering thermal force. The divertor plasma is composed of four regions in terms of momentum transport between hydrogen and carbon impurity: Momentum transferring region, equilibrium region, hydrogen recycling region and carbon recycling region. In the equilibrium region where the friction force is counterbalanced by the thermal force, the localization of carbon impurity occurs. The sufficient condition to avoid the reverse of carbon velocity due to the thermal force is evaluated. (orig.)

  13. Use of residual hydrocarbons treated by Thermal Plasma (recovery of energy by-products)

    International Nuclear Information System (INIS)

    Carreno B, J.A.; Pacheco S, J.O.; Ramos F, F.; Cruz A, A.; Duran G, M.

    2001-01-01

    The emergence of new technologies is getting greater importance for the control of pollution. One of them is the destruction of hazardous wastes treated by thermal plasma, which is of special interest for the efficient treatment of the hazardous wastes since the heat generated by thermal plasma is able to destroy the molecular bonds generating solids and gaseous products which do not represent danger for the human being and the environment. The thermal plasma is the suitable technology for treating a wide range of hazardous wastes, including the residual hydrocarbons from the refinement process of petroleum, plasma exceeds the barrier of 3000 Centigrade. The efficiency of the degradation of residues is greater than 99.99%. Toxic emissions are not generated to environment as SO 2 , NO x and CO 2 neither dioxins and furans by being a pyrolysis process. The use of hydrogen as fuel does not generate pollution to environment. (Author)

  14. DC Thermal Plasma Design and Utilization for the Low Density Polyethylene to Diesel Oil Pyrolysis Reaction

    Directory of Open Access Journals (Sweden)

    Hossam A. Gabbar

    2017-06-01

    Full Text Available The exponential increase of plastic production produces 100 million tonnes of waste plastics annually which could be converted into hydrocarbon fuels in a thermal cracking process called pyrolysis. In this research work, a direct current (DC thermal plasma circuit is designed and used for conversion of low density polyethylene (LDPE into diesel oil in a laboratory scale pyrolysis reactor. The experimental setup uses a 270 W DC thermal plasma at operating temperatures in the range of 625 °C to 860 °C for a low density polyethylene (LDPE pyrolysis reaction at pressure = −0.95, temperature = 550 °C with τ = 30 min at a constant heating rate of 7.8 °C/min. The experimental setup consists of a vacuum pump, closed system vessel, direct current (DC plasma circuit, and a k-type thermocouple placed a few millimeters from the reactant sample. The hydrocarbon products are condensed to diesel oil and analyzed using flame ionization detector (FID gas chromatography. The analysis shows 87.5% diesel oil, 1,4-dichlorobenzene (Surr, benzene, ethylbenzene and traces of toluene and xylene. The direct current (DC thermal plasma achieves 56.9 wt. % of diesel range oil (DRO, 37.8 wt. % gaseous products and minimal tar production. The direct current (DC thermal plasma shows reliability, better temperature control, and high thermal performance as well as the ability to work for long operation periods.

  15. Star formation through thermal instability of radiative plasma with finite electron inertia and finite Larmor radius corrections

    Energy Technology Data Exchange (ETDEWEB)

    Kaothekar, Sachin, E-mail: sackaothekar@gmail.com [Department of Physics, Mahakal Institute of Technology, Ujjain-456664, Madhya Pradesh (India)

    2016-08-15

    I have studied the effects of finite electron inertia, finite ion Larmor radius (FLR) corrections, and radiative heat-loss function on the thermal instability of an infinite homogeneous, viscous plasma incorporating the effect of thermal conductivity for star formation in interstellar medium (ISM). A general dispersion relation is derived using the normal mode analysis method with the help of relevant linearized perturbation equations of the problem. The wave propagation is discussed for longitudinal and transverse directions to the external magnetic field and the conditions of modified thermal instabilities and stabilities are discussed in different cases. We find that the thermal instability criterion is get modified into radiative instability criterion by inclusion of radiative heat-loss functions with thermal conductivity. The viscosity of medium removes the effect of FLR corrections from the condition of radiative instability. Numerical calculation shows stabilizing effect of heat-loss function, viscosity and FLR corrections, and destabilizing effect of finite electron inertia on the thermal instability. Results carried out in this paper shows that stars are formed in interstellar medium mainly due to thermal instability.

  16. Star formation through thermal instability of radiative plasma with finite electron inertia and finite Larmor radius corrections

    Directory of Open Access Journals (Sweden)

    Sachin Kaothekar

    2016-08-01

    Full Text Available I have studied the effects of finite electron inertia, finite ion Larmor radius (FLR corrections, and radiative heat-loss function on the thermal instability of an infinite homogeneous, viscous plasma incorporating the effect of thermal conductivity for star formation in interstellar medium (ISM. A general dispersion relation is derived using the normal mode analysis method with the help of relevant linearized perturbation equations of the problem. The wave propagation is discussed for longitudinal and transverse directions to the external magnetic field and the conditions of modified thermal instabilities and stabilities are discussed in different cases. We find that the thermal instability criterion is get modified into radiative instability criterion by inclusion of radiative heat-loss functions with thermal conductivity. The viscosity of medium removes the effect of FLR corrections from the condition of radiative instability. Numerical calculation shows stabilizing effect of heat-loss function, viscosity and FLR corrections, and destabilizing effect of finite electron inertia on the thermal instability. Results carried out in this paper shows that stars are formed in interstellar medium mainly due to thermal instability.

  17. Electrochemical performance of Si-multiwall carbon nanotube nanocomposite anode synthesized by thermal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Na, Ye-Seul; Yoo, Hyeonseok; Kim, Tae-Hee; Choi, Jinsub; Lee, Wan In; Choi, Sooseok, E-mail: sooseok@jejunu.ac.kr; Park, Dong-Wha, E-mail: dwpark@inha.ac.kr

    2015-07-31

    Lithium-ion (Li-ion) batteries are widely used in electric devices and vehicles. Silicon is a promising material for the anode of Li-ion battery due to high theoretical specific capacity. However, it shows large volume changes during charge–discharge cycles leading to the pulverization of electrode. In order to improve such disadvantage, a multiwall carbon nanotube (MWCNT) has been used with silicon as composite material. In this work, Si-MWCNT nanocomposite was prepared in thermal plasma by attaching silicon nanoparticles to MWCNT column. Electrochemical tests for raw materials and synthesized nanocomposites were carried out. The discharge capacities of silicon, MWCNT, synthesized nanocomposites collected from a reaction tube, and a chamber were 4000, 310, 200, and 1447 mAh/g, respectively. - Highlights: • Si-Multiwall carbon nanotube nanocomposite was synthesized by thermal plasma. • The effect on the collection position of product after experiment was examined. • Cycle performance of electrodes was measured. • Product collected from chamber showed good electrochemical performance.

  18. Understanding CO2 decomposition by thermal plasma with supersonic expansion quench

    Science.gov (United States)

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

    2018-04-01

    CO2 pyrolysis by thermal plasma was investigated, and a high conversion rate of 33% and energy efficiency of 17% were obtained. The high performance benefited from a novel quenching method, which synergizes the converging nozzle and cooling tube. To understand the synergy effect, a computational fluid dynamics simulation was carried out. A quick quenching rate of 107 K s‑1 could be expected when the pyrolysis gas temperature decreased from more than 3000 to 1000 K. According to the simulation results, the quenching mechanism was discussed as follows: first, the compressible fluid was adiabatically expanded in the converging nozzle and accelerated to sonic speed, and parts of the heat energy converted to convective kinetic energy; second, the sonic fluid jet into the cooling tube formed a strong eddy, which greatly enhanced the heat transfer between the inverse-flowing fluid and cooling tube. These two mechanisms ensure a quick quenching to prevent the reverse reaction of CO2 pyrolysis gas when it flows out from the thermal plasma reactor.

  19. Hydrogen and Carbon Black Production from the Degradation of Methane by Thermal Plasma

    Directory of Open Access Journals (Sweden)

    Leila Cottet

    2014-05-01

    Full Text Available Methane gas (CH4 is the main inducer of the so called greenhouse gases effect. Recent scientific research aims to minimize the accumulation of this gas in the atmosphere and to develop processes capable of producing stable materials with added value. Thermal plasma technology is a promising alternative to these applications, since it allows obtaining H2 and solid carbon from CH4, without the parallel formation of byproducts such as CO2 and NOx. In this work, CH4 was degraded by thermal plasma in order to produce hydrogen (H2 and carbon black. The degradation efficiency of CH4, selectivity for H2 production as well as the characterization of carbon black were studied. The best results were obtained in the CH4 flow rate of 5 L min-1 the degradation percentage and the selectivity for H2 production reached 98.8 % and 48.4 %, respectively. At flow rates of less than 5 L min-1 the selectivity for H2 production increases and reaches 91.9 %. The carbon black has obtained amorphous with hydrophobic characteristics and can be marketed to be used in composite material, and can also be activated chemically and/or physically and used as adsorbent material.

  20. Influence of Bondcoat Spray Process on Lifetime of Suspension Plasma-Sprayed Thermal Barrier Coatings

    Science.gov (United States)

    Gupta, M.; Markocsan, N.; Li, X.-H.; Östergren, L.

    2018-01-01

    Development of thermal barrier coatings (TBCs) manufactured by suspension plasma spraying (SPS) is of high commercial interest as SPS has been shown capable of producing highly porous columnar microstructures similar to the conventionally used electron beam-physical vapor deposition. However, lifetime of SPS coatings needs to be improved further to be used in commercial applications. The bondcoat microstructure as well as topcoat-bondcoat interface topography affects the TBC lifetime significantly. The objective of this work was to investigate the influence of different bondcoat deposition processes for SPS topcoats. In this work, a NiCoCrAlY bondcoat deposited by high velocity air fuel (HVAF) was compared to commercial vacuum plasma-sprayed NiCoCrAlY and PtAl diffusion bondcoats. All bondcoat variations were prepared with and without grit blasting the bondcoat surface. SPS was used to deposit the topcoats on all samples using the same spray parameters. Lifetime of these samples was examined by thermal cyclic fatigue testing. Isothermal heat treatment was performed to study bondcoat oxidation over time. The effect of bondcoat deposition process and interface topography on lifetime in each case has been discussed. The results show that HVAF could be a suitable process for bondcoat deposition in SPS TBCs.

  1. Properties of thermal air plasma with admixing of copper and carbon

    International Nuclear Information System (INIS)

    Fesenko, S; Veklich, A; Boretskij, V; Cressault, Y; Gleizes, A; Teulet, Ph

    2014-01-01

    This paper deals with investigations of air plasma with admixing of copper and carbon. Model plasma source unit with real breaking arc was used for the simulation of real discharges, which can be occurred during sliding of Cu-C composite electrodes on copper wire at electromotive vehicles. The complex technique of plasma property studies is developed. From one hand, the radial profiles of temperature and electron density in plasma of electric arc discharge in air between Cu-C composite and copper electrodes in air flow were measured by optical spectroscopy techniques. From another hand, the radial profiles of electric conductivity of plasma mixture were calculated by solution of energy balance equation. It was assumed that the thermal conductivity of air plasma is not depending on copper or carbon vapor admixtures. The electron density is obtained from electric conductivity profiles by calculation in assumption of local thermodynamic equilibrium in plasma. Computed in such way radial profiles of electron density in plasma of electric arc discharge in air between copper electrodes were compared with experimentally measured profiles. It is concluded that developed techniques of plasma diagnostics can be reasonably used in investigations of thermal plasma with copper and carbon vapors

  2. Skin-effect in a dense ionizing plasma

    International Nuclear Information System (INIS)

    Ivanenkov, G.V.; Taranenko, S.B.

    1989-01-01

    Effect of multiple ionization and radiation (bremmstrahlung and photorecombination) on skin effect in a dense plasma is investigated. Limiting cases are considered: 1) fast skin-effect, when plasma movement and any types of losses (radiation, electron thermal conductivity) have no time to manifest themselves during short heating times; 2) deceleration of skinning under effect of radiation achieving equilibrium with Joule heating. Self-simulating solutions of the problem for half-space are investigated. The results are applied to analysing experiments with exploding wires. It is shown that under conditions, typical of heavy-current decelerators tubular structures are produced as a result of heat and current skinning under free dispersion of plasma produced during the explosion. Their dimensions are of the order of dozens of microns, and the temperature exceeds 50 eV. The linear power and complete ''tube'' radiation yield at this stage are able to make a substantial contribution to the energy balance in the group

  3. Radioactive waste combustion-vitrification under arc plasma: thermal and dynamic modelling

    International Nuclear Information System (INIS)

    Barthelemy, B.

    2003-06-01

    This thesis concerns the thermal and dynamic modelling for a combustion/vitrification process of surrogate radioactive waste under transferred arc plasma. The writer presents the confinement processes for radioactive waste using arc plasma and the different software used to model theses processes. This is followed by a description of our experimental equipment including a plasma arc reactor and an inductive system allowing the homogenization of glass temperature. A combustion/vitrification test is described. Thermal and material balances were discussed. The temperature fields of plasma arc and the glass frit conductivity are measured. Finally, the writer describes and clarifies the equations solved for the simulations of the electrically plasma arc and the glass melting including the thin layer of glass frit coating the crucible cold walls. The modelling results are presented in the form of spatial distribution of temperature, velocity and voluminal power... (author)

  4. Radioactive waste combustion / vitrification under arc plasma: thermal and dynamic modelling

    International Nuclear Information System (INIS)

    Barthelemy, B.

    2003-01-01

    This thesis concerns the thermal and dynamic modelling for a combustion/vitrification process of surrogate radioactive waste under transferred arc plasma. The writer presents the confinement processes for radioactive waste using arc plasma and the different software used to model theses processes. This is followed by a description of our experimental equipment including a plasma arc reactor and an inductive system allowing the homogenization of glass temperature. A combustion/vitrification test is described. Thermal and material balances were discussed. The temperature fields of plasma arc and the glass frit conductivity are measured. Finally, the writer describes and clarifies the equations solved for the simulations of the electrically plasma arc and the glass melting including the thin layer of glass frit coating the crucible cold walls. The modelling results are presented in the form of spatial distribution of temperature, velocity and volume power... (author)

  5. Propagation of sound and thermal waves in an ionizing-recombining hydrogen plasma: Revision of results

    International Nuclear Information System (INIS)

    Di Sigalotti, Leonardo G.; Sira, Eloy; Tremola, Ciro

    2002-01-01

    The propagation of acoustic and thermal waves in a heat conducting, hydrogen plasma, in which photoionization and photorecombination [H + +e - H+hν(χ)] processes are progressing, is re-examined here using linear analysis. The resulting dispersion equation is solved analytically and the results are compared with previous solutions for the same plasma model. In particular, it is found that wave propagation in a slightly and highly ionized hydrogen plasma is affected by crossing between acoustic and thermal modes. At temperatures where the plasma is partially ionized, waves of all frequencies propagate without the occurrence of mode crossing. These results disagree with those reported in previous work, thereby leading to a different physical interpretation of the propagation of small linear disturbances in a conducting, ionizing-recombining, hydrogen plasma

  6. Effects of Nonequilibrium Plasmas on Eukaryotic Cells

    Science.gov (United States)

    2009-05-01

    effects of the plasma bullets on bacteria of dental relevance, Streptococcus mutans , which is implicated in the onset and progression of dental caries...Hynes " Experimental Investigations of Plasma Bullets and their Effects on Streptococcus mutans ", In Proc. 2nd Int. Conf. Plasma Medicine, San...S. mutans is a cariogenic organism that contributes to caries in infants, children and adults. S. mutans alone are not difficult to destroy; however

  7. Cell death induced on cell cultures and nude mouse skin by non-thermal, nanosecond-pulsed generated plasma.

    Directory of Open Access Journals (Sweden)

    Arnaud Duval

    Full Text Available Non-thermal plasmas are gaseous mixtures of molecules, radicals, and excited species with a small proportion of ions and energetic electrons. Non-thermal plasmas can be generated with any high electro-magnetic field. We studied here the pathological effects, and in particular cell death, induced by nanosecond-pulsed high voltage generated plasmas homogeneously applied on cell cultures and nude mouse skin. In vitro, Jurkat cells and HMEC exhibited apoptosis and necrosis, in dose-dependent manner. In vivo, on nude mouse skin, cell death occurred for doses above 113 J/cm(2 for the epidermis, 281 J/cm(2 for the dermis, and 394 J/cm(2 for the hypodermis. Using electron microscopy, we characterized apoptosis for low doses and necrosis for high doses. We demonstrated that these effects were not related to thermal, photonic or pH variations, and were due to the production of free radicals. The ability of cold plasmas to generate apoptosis on cells in suspension and, without any sensitizer, on precise skin areas, opens new fields of application in dermatology for extracorporeal blood cell treatment and the eradication of superficial skin lesions.

  8. Collisional Thermalization in Strongly Coupled Ultracold Neutral Plasmas

    Science.gov (United States)

    2017-01-25

    calculated collisions rates in a strongly coupled plasma. From Bannasch et al., PRL 109, 185008 (2012). DISTRIBUTION A: Distribution approved for public...applicability to other plasmas.) We use a Green- Kubo relation to extract the diffusion constant from our measurements of the relaxation towards...strongly coupled systems. Our measurements (data symbols) agree with numerical calculations (solid lines) from J. Daligault, PRL 108, 225004 (2012

  9. Thermal conductivity of plasma modified polyethylene terephthalate and polyamide-6 layers

    Directory of Open Access Journals (Sweden)

    G. Kalacska

    2016-05-01

    Full Text Available Tribological performance of the materials greatly depends on the temperature of the contacting zones and surfaces and hence on the heat conducting behaviour of the materials. Heat conduction of polymers is, however, greatly affected even by a very narrow (few tens of nm modified layer formed on the surface after subjecting the polymer to plasma treatment. In this article the heat flow inhibiting properties of plasma modified surface layers were investigated on polyethylene terephthalate (PET and polyamide-6 (PA6 engineering polymers. Nitrogen Plasma Immersion Ion Implantation gave rise to compositional and structural changes of the polymers in a depth of 110 nm. It was found that even this thin layer exhibited significant heat flow inhibiting effect. The modified layer considerably decreased the thermal conductivity coefficient of the treated polymer and resulted in a reduced heat transmission for PET and PA6 by 33 and 28%, respectively. This new information supports and is in accordance with the former tribological results about extra friction heat generation experienced under NPIII surface layer of PA6 and PET during dry sliding.

  10. Non-thermal plasma-induced photocatalytic degradation of 4-chlorophenol in water

    Energy Technology Data Exchange (ETDEWEB)

    Hao Xiaolong [Institute of Environmental Pollution Control Technologies, Xixi Campus, Zhejiang University, Hangzhou 310028, Zhejiang (China); Zhou Ming Hua [Institute of Environmental Pollution Control Technologies, Xixi Campus, Zhejiang University, Hangzhou 310028, Zhejiang (China); Lei Lecheng [Institute of Environmental Pollution Control Technologies, Xixi Campus, Zhejiang University, Hangzhou 310028, Zhejiang (China)]. E-mail: lclei@zju.edu.cn

    2007-03-22

    TiO{sub 2} photocatalyst (P-25) (50 mg L{sup -1}) was tentatively introduced into pulsed high-voltage discharge process for non-thermal plasma-induced photocatalytic degradation of the representative mode organic pollutant parachlorophenol (4-CP), including other compounds phenol and methyl red in water. The experimental results showed that rate constant of 4-CP degradation, energy efficiency for 4-CP removal and TOC removal with TiO{sub 2} were obviously increased. Pulsed high-voltage discharge process with TiO{sub 2} had a promoted effect for the degradation of these pollutants under a broad range of liquid conductivity. Furthermore, the apparent formation rates of chemically active species (e.g., ozone and hydrogen peroxide) were increased, the hydrogen peroxide formation rate from 1.10 x 10{sup -6} to 1.50 x 10{sup -6} M s{sup -1}, the ozone formation rate from 1.99 x 10{sup -8} to 2.35 x 10{sup -8} M s{sup -1}, respectively. In addition, this process had no influence on the photocatalytic properties of TiO{sub 2}. The introduction of TiO{sub 2} photocatalyst into pulsed discharge plasma process in the utilizing of ultraviolet radiation and electric field in pulsed discharge plasma process enhanced the yields of chemically active species, which were available for highly efficient removal and mineralization of organic pollutants.

  11. Non-thermal plasma-induced photocatalytic degradation of 4-chlorophenol in water.

    Science.gov (United States)

    Hao, Xiao Long; Zhou, Ming Hua; Lei, Le Cheng

    2007-03-22

    TiO(2) photocatalyst (P-25) (50mgL(-1)) was tentatively introduced into pulsed high-voltage discharge process for non-thermal plasma-induced photocatalytic degradation of the representative mode organic pollutant parachlorophenol (4-CP), including other compounds phenol and methyl red in water. The experimental results showed that rate constant of 4-CP degradation, energy efficiency for 4-CP removal and TOC removal with TiO(2) were obviously increased. Pulsed high-voltage discharge process with TiO(2) had a promoted effect for the degradation of these pollutants under a broad range of liquid conductivity. Furthermore, the apparent formation rates of chemically active species (e.g., ozone and hydrogen peroxide) were increased, the hydrogen peroxide formation rate from 1.10x10(-6) to 1.50x10(-6)Ms(-1), the ozone formation rate from 1.99x10(-8) to 2.35x10(-8)Ms(-1), respectively. In addition, this process had no influence on the photocatalytic properties of TiO(2). The introduction of TiO(2) photocatalyst into pulsed discharge plasma process in the utilizing of ultraviolet radiation and electric field in pulsed discharge plasma process enhanced the yields of chemically active species, which were available for highly efficient removal and mineralization of organic pollutants.

  12. Non-thermal plasma-induced photocatalytic degradation of 4-chlorophenol in water

    International Nuclear Information System (INIS)

    Hao Xiaolong; Zhou Ming Hua; Lei Lecheng

    2007-01-01

    TiO 2 photocatalyst (P-25) (50 mg L -1 ) was tentatively introduced into pulsed high-voltage discharge process for non-thermal plasma-induced photocatalytic degradation of the representative mode organic pollutant parachlorophenol (4-CP), including other compounds phenol and methyl red in water. The experimental results showed that rate constant of 4-CP degradation, energy efficiency for 4-CP removal and TOC removal with TiO 2 were obviously increased. Pulsed high-voltage discharge process with TiO 2 had a promoted effect for the degradation of these pollutants under a broad range of liquid conductivity. Furthermore, the apparent formation rates of chemically active species (e.g., ozone and hydrogen peroxide) were increased, the hydrogen peroxide formation rate from 1.10 x 10 -6 to 1.50 x 10 -6 M s -1 , the ozone formation rate from 1.99 x 10 -8 to 2.35 x 10 -8 M s -1 , respectively. In addition, this process had no influence on the photocatalytic properties of TiO 2 . The introduction of TiO 2 photocatalyst into pulsed discharge plasma process in the utilizing of ultraviolet radiation and electric field in pulsed discharge plasma process enhanced the yields of chemically active species, which were available for highly efficient removal and mineralization of organic pollutants

  13. The effect of the ergodic divertor on electron thermal confinement

    International Nuclear Information System (INIS)

    Harris, G.R.; Capes, H.; Garbet, X.

    1992-06-01

    The thermal confinement within the confinement zone of Tore Supra ohmically heated deuterium plasmas bounded by the ergodic divertor (ED) configuration is studied in a 1 1/2D analysis of the local power balance. Although the edge electron temperature and mean electron density (n e ) are both on average halved with application of the ED, the mean electron thermal diffusivity χ e shows the same density dependence as exhibited by standard ohmic limiter discharges, i.e., an Alcator-like inverse dependence on (n e ) at low density and a saturation at high density. The ion thermal transport at low to medium densities in both limiter and ED discharges is between 10 to 20 times that predicted by neoclassical theory. Comparing ED and limiter plasmas of the same density, a strong plasma decontamination is observed, with a reduction, in Z eff by between 1.0 to 1.5. The effective decoupling of (n e ) and Z eff by the ED and the invariant behaviour of χ e imply that electron thermal transport is only weakly dependent on Z eff in ohmic Tore Supra discharges

  14. Thermal shock fracture of graphite armor plate under the heat load of plasma disruption

    International Nuclear Information System (INIS)

    Horie, Tomoyoshi; Seki, Masahiro; Ohmori, Junji

    1989-01-01

    Experiments on the thermal shock brittle fracture of graphite plates were performed. Thermal loading which simulated a plasma disruption was produced by an electron beam facility. Pre-cracks produced on the surface propagated to the inside of the specimen even if the thermal stress on the surface was compressive. Two mechanisms are possible to produce tensile stress around the crack tip under thermal shock conditions. Temperature, thermal stress, and the stress intensity factor for the specimen were analyzed based on the finite element method for various heating conditions. The trend of experimental results under the asymmetric heating agrees qualitatively with the analytical results. This phenomenon is important for the design of plasma facing components made of graphite. Establishment of a lifetime prediction procedure including fatigue, fatigue crack growth, and brittle fracture is needed for graphite armors. (orig.)

  15. Rocket-borne thermal plasma instrument "MIPEX" for the ionosphere D, E layer in-situ measurements

    Science.gov (United States)

    Fang, H. K.; Chen, A. B. C.; Lin, C. C. H.; Wu, T. J.; Liu, K. S.; Chuang, C. W.

    2017-12-01

    In this presentation, the design concepts, performances and status of a thermal plasma particle instrument package "Mesosphere and Ionosphere Plasma Exploration complex (MIPEX)", which is going to be installed onboard a NSPO-funded hybrid rocket, to investigate the electrodynamic processes in ionosphere D, E layers above Taiwan are reported. MIPEX is capable of measuring plasma characteristics including ion temperature, ion composition, ion drift, electron temperature and plasma density at densities as low as 1-10 cm-1. This instrument package consists of an improved retarding potential analyzer with a channel electron multiplier (CEM), a simplified ion drift meter and a planar Langmuir probe. To achieve the working atmospheric pressure of CEM at the height of lower D layer ( 70km), a portable vacuum pump is also placed in the package. A prototype set of the MIPEX has been developed and tested in the Space Plasma Operation Chamber (SPOC) at NCKU, where in ionospheric plasma is generated by back-diffusion plasma sources. A plasma density of 10-106 cm-1, ion temperature of 300-1500 K and electron temperature of 1000-3000K is measured and verified. Limited by the flight platform and the performance of the instruments, the in-situ plasma measurements at the Mesosphere and lower Thermosphere is very challenging and rare. MIPEX is capable of extending the altitude of the effective plasma measurement down to 70 km height and this experiment can provide unique high-quality data of the plasma environment to explore the ion distribution and the electrodynamic processes in the Ionosphere D, E layers at dusk.

  16. Chlorobenzene degeradation by non-thermal plasma combined with EG-TiO{sub 2}/ZnO as a photocatalyst: Effect of photocatalyst on CO{sub 2} selectivity and byproducts reduction

    Energy Technology Data Exchange (ETDEWEB)

    Ghorbani Shahna, Farshid; Bahrami, Abdulrahman [Center of Excellence for Occupational Health and Research Center for Health Science, School of Public Health, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of); Alimohammadi, Iraj; Yarahmadi, Rassuol [Department of Occupational Health, School of Public Health, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Jaleh, Babak; Gandomi, Mastaneh [Faculty of Science, Physics Department, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of); Ebrahimi, Hossein, E-mail: hossein.ebrahimi@yahoo.com [Department of Occupational Health, School of Public Health, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Ad-Din Abedi, Kamal [Department of Occupational Health Engineering, Faculty of Health, Kurdistan University of Medical sciences, Sanandaj (Iran, Islamic Republic of)

    2017-02-15

    Highlights: • TiO{sub 2} and ZnO Nano particles were coated on the surface of expanded graphite. • Expanded graphite-TiO{sub 2}/ZnO nano composite under UV light was placed downstream non-thermal plasma reactor. • Chlorobenzene removal and selectivity of CO{sub 2} were enhanced in combined system. • Produced harmful byproducts from plasma reactor were reduced dramatically in combined system. - Abstract: The non-thermal plasma (NTP) technique, which suffers from low selectivity in complete oxidation of volatile organic compounds to CO{sub 2} and H{sub 2}O, creates unwanted and harmful byproducts. NTP in concert with photocatalyst can resolve this limitation due to additional oxidation. TiO{sub 2} and ZnO nanoparticles were coated on the surface of the expanded graphite and placed downstream of the NTP reactor under UV light. In this study, to compare the performance of NTP and the combined system, chlorobenzene removal, selectivity of CO{sub 2} and byproducts formation were investigated. The results showed that the combined system enhanced both the removal efficiency and CO{sub 2} selectivity. The output gas of the NTP reactor contained chlorobenzene, phosgene, O{sub 3}, NO, NO{sub 2}, CO, CO{sub 2}, HCL and CL. The bulk of these byproducts was oxidized on the surface of the nanocomposite; as a result, the content of the byproducts in the output gas of the combined system decreased dramatically. The removal efficiency and CO{sub 2} selectivity increased by rising the applied voltage and residence time because the collision between active species and pollutant molecules increases. Based on these results, the combined system is preferred due to a higher performance and lower formation of harmful byproducts.

  17. Non-Thermal Plasma Treatment Diminishes Fungal Viability and Up-Regulates Resistance Genes in a Plant Host

    Science.gov (United States)

    Panngom, Kamonporn; Lee, Sang Hark; Park, Dae Hoon; Sim, Geon Bo; Kim, Yong Hee; Uhm, Han Sup; Park, Gyungsoon; Choi, Eun Ha

    2014-01-01

    Reactive oxygen and nitrogen species can have either harmful or beneficial effects on biological systems depending on the dose administered and the species of organism exposed, suggesting that application of reactive species can possibly produce contradictory effects in disease control, pathogen inactivation and activation of host resistance. A novel technology known as atmospheric-pressure non-thermal plasma represents a means of generating various reactive species that adversely affect pathogens (inactivation) while simultaneously up-regulating host defense genes. The anti-microbial efficacy of this technology was tested on the plant fungal pathogen Fusarium oxysporum f.sp. lycopersici and its susceptible host plant species Solanum lycopercicum. Germination of fungal spores suspended in saline was decreased over time after exposed to argon (Ar) plasma for 10 min. Although the majority of treated spores exhibited necrotic death, apoptosis was also observed along with the up-regulation of apoptosis related genes. Increases in the levels of peroxynitrite and nitrite in saline following plasma treatment may have been responsible for the observed spore death. In addition, increased transcription of pathogenesis related (PR) genes was observed in the roots of the susceptible tomato cultivar (S. lycopercicum) after exposure to the same Ar plasma dose used in fungal inactivation. These data suggest that atmospheric-pressure non-thermal plasma can be efficiently used to control plant fungal diseases by inactivating fungal pathogens and up-regulating mechanisms of host resistance. PMID:24911947

  18. Non-thermal plasma treatment diminishes fungal viability and up-regulates resistance genes in a plant host.

    Science.gov (United States)

    Panngom, Kamonporn; Lee, Sang Hark; Park, Dae Hoon; Sim, Geon Bo; Kim, Yong Hee; Uhm, Han Sup; Park, Gyungsoon; Choi, Eun Ha

    2014-01-01

    Reactive oxygen and nitrogen species can have either harmful or beneficial effects on biological systems depending on the dose administered and the species of organism exposed, suggesting that application of reactive species can possibly produce contradictory effects in disease control, pathogen inactivation and activation of host resistance. A novel technology known as atmospheric-pressure non-thermal plasma represents a means of generating various reactive species that adversely affect pathogens (inactivation) while simultaneously up-regulating host defense genes. The anti-microbial efficacy of this technology was tested on the plant fungal pathogen Fusarium oxysporum f.sp. lycopersici and its susceptible host plant species Solanum lycopercicum. Germination of fungal spores suspended in saline was decreased over time after exposed to argon (Ar) plasma for 10 min. Although the majority of treated spores exhibited necrotic death, apoptosis was also observed along with the up-regulation of apoptosis related genes. Increases in the levels of peroxynitrite and nitrite in saline following plasma treatment may have been responsible for the observed spore death. In addition, increased transcription of pathogenesis related (PR) genes was observed in the roots of the susceptible tomato cultivar (S. lycopercicum) after exposure to the same Ar plasma dose used in fungal inactivation. These data suggest that atmospheric-pressure non-thermal plasma can be efficiently used to control plant fungal diseases by inactivating fungal pathogens and up-regulating mechanisms of host resistance.

  19. Non-thermal plasma treatment diminishes fungal viability and up-regulates resistance genes in a plant host.

    Directory of Open Access Journals (Sweden)

    Kamonporn Panngom

    Full Text Available Reactive oxygen and nitrogen species can have either harmful or beneficial effects on biological systems depending on the dose administered and the species of organism exposed, suggesting that application of reactive species can possibly produce contradictory effects in disease control, pathogen inactivation and activation of host resistance. A novel technology known as atmospheric-pressure non-thermal plasma represents a means of generating various reactive species that adversely affect pathogens (inactivation while simultaneously up-regulating host defense genes. The anti-microbial efficacy of this technology was tested on the plant fungal pathogen Fusarium oxysporum f.sp. lycopersici and its susceptible host plant species Solanum lycopercicum. Germination of fungal spores suspended in saline was decreased over time after exposed to argon (Ar plasma for 10 min. Although the majority of treated spores exhibited necrotic death, apoptosis was also observed along with the up-regulation of apoptosis related genes. Increases in the levels of peroxynitrite and nitrite in saline following plasma treatment may have been responsible for the observed spore death. In addition, increased transcription of pathogenesis related (PR genes was observed in the roots of the susceptible tomato cultivar (S. lycopercicum after exposure to the same Ar plasma dose used in fungal inactivation. These data suggest that atmospheric-pressure non-thermal plasma can be efficiently used to control plant fungal diseases by inactivating fungal pathogens and up-regulating mechanisms of host resistance.

  20. Expanding Thermal Plasma Chemical Vapour Deposition of ZnO:Al Layers for CIGS Solar Cells

    Directory of Open Access Journals (Sweden)

    K. Sharma

    2014-01-01

    Full Text Available Aluminium-doped zinc oxide (ZnO:Al grown by expanding thermal plasma chemical vapour deposition (ETP-CVD has demonstrated excellent electrical and optical properties, which make it an attractive candidate as a transparent conductive oxide for photovoltaic applications. However, when depositing ZnO:Al on CIGS solar cell stacks, one should be aware that high substrate temperature processing (i.e., >200°C can damage the crucial underlying layers/interfaces (such as CIGS/CdS and CdS/i-ZnO. In this paper, the potential of adopting ETP-CVD ZnO:Al in CIGS solar cells is assessed: the effect of substrate temperature during film deposition on both the electrical properties of the ZnO:Al and the eventual performance of the CIGS solar cells was investigated. For ZnO:Al films grown using the high thermal budget (HTB condition, lower resistivities, ρ, were achievable (~5 × 10−4 Ω·cm than those grown using the low thermal budget (LTB conditions (~2 × 10−3 Ω·cm, whereas higher CIGS conversion efficiencies were obtained for the LTB condition (up to 10.9% than for the HTB condition (up to 9.0%. Whereas such temperature-dependence of CIGS device parameters has previously been linked with chemical migration between individual layers, we demonstrate that in this case it is primarily attributed to the prevalence of shunt currents.

  1. Ion thermal conductivity for a pure tokamak plasma

    International Nuclear Information System (INIS)

    Bolton, C.W. III.

    1981-06-01

    The ion thermal conductivity is calculated for a wide range of aspect ratios and collision frequencies. The calculation is done by solving the drift kinetic equation, with a model collision operator, using a finite element method, and then calculating the energy weighted friction force to determine the heat flux. The thermal conductivity, determined from the heat flux, is then curve fitted to analytic formulas. These formulas allow the conductivity to be calculated at all collision frequencies and aspect ratios down to about 3

  2. Thermal efficiency of a non-transferred thermal plasma cannon; Eficiencia termica de un canon de plasma termico no-transferido

    Energy Technology Data Exchange (ETDEWEB)

    Mercado, A; Cota, G; Merlo, L; Pacheco, J; Pena, R; Cruz, A [Instituto nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    This work shows a thermal efficiency research ({nu}) for a plasma torch in d.c. which was carried out through the realization of an energy balance around the system under consideration. The plasma torch is manufactured in copper with a tungsten incrustations in cathode. The gas used was argon and the gas fluxes were at the rank of 10 and 40 lt/min to the total pressure of 1.2 bar (1.1 atm). With these conditions it was worked with electric currents at the rank of 40 and 180 A. The data were collected through a data acquisition card which was programmed in Windows environment. (Author)

  3. Thermal de-isolation of silicon microstructures in a plasma etching environment

    International Nuclear Information System (INIS)

    Lee, Yong-Seok; Jang, Yun-Ho; Kim, Yong-Kweon; Kim, Jung-Mu

    2013-01-01

    This paper presents a theoretical and experimental strategy for thermal de-isolation of silicon microstructures during a plasma etching process. Heat sinking blocks and thin metal layers are implemented around a thermally isolated mass to avoid severe spring width losses by a steep temperature rise. Thermal de-isolation significantly reduces the fabrication errors from −51.0% to −9.0% and from −39.5% to −6.7% for spring widths and resonant frequencies, respectively. Thermal de-isolation also reduces the standard deviation of resonant frequencies from 8.7% to 1.5% across a wafer, which clearly demonstrates the proposed method. (paper)

  4. Thermal catastrophe in the plasma sheet boundary layer

    International Nuclear Information System (INIS)

    Smith, R.A.; Goertz, C.K.; Grossmann, W.

    1986-01-01

    This letter presents a first step towards a substorm model including particle heating and transport in the plasma sheet boundary layer (PSBL). The heating mechanism discussed is resonant absorption of Alfven waves. For some assumed MHD perturbation incident from the tail lobes onto the plasma sheet, the local heating rate in the PSBL has the form of a resonance function of the one-fluid plasma temperature. Balancing the local heating by convective transport of the heated plasma toward the central plasma sheet, and ''equation of state'' is found for the steady-state PSBL whose solution has the form of a mathematical catastrophe: at a critical value of a parameter containing the incident power flux, the local density, and the convection velocity, the equilibrium temperature jumps discontinuously. Associating this temperature increase with the abrupt onset of the substorm expansion phase, the catastrophe model indicates at least three ways in which the onset may be triggered. Several other consequences related to substorm dynamics are suggested by the simple catastrophe model

  5. TPSS plasma engineering studies: profile effects and plasma power balance

    International Nuclear Information System (INIS)

    Borowski, S.K.; Strickler, D.J.

    1985-01-01

    A computationally fast profile-averaged, steady-state plasma model has been developed to allow studies of radial effects in ignited and driven tokamak systems. This code was used to search for the smallest size tokamak consistent with power balance calculations

  6. To a question on thermal protection of constructional elements of vacuum-plasma devices

    International Nuclear Information System (INIS)

    Borisko, V.N.; Borisko, S.V.; Zinovev, D.V.; Lapshin, V.I.; Tselujko, A.F.

    2005-01-01

    The progress in development of vacuum-plasma devices is connected with the design and creation of constructional elements from materials, which have a high erosion resistance and can maintain the large specific flux of energy per effective area. Recently as the materials of such constructional elements it was offered to use the reversible sorbents of hydrogen of Zr-V system, which have high-rates of sorption-desorption and large thermal effect of the hydride phases decomposition. In the paper an experimental research of the thermal conditions features of the metal-hydride electrodes, which subjected of the energy loads in the vacuum-plasma devices, are given. The simulation of the energy loads on the electrodes was carried out with the help of gas discharge plasma as there is an possibility to vary the energy spectrum of the bombarding particles and to gather a necessary radiation dose to the material surface. For comparative examinations of various materials under the irradiation by high-energy heavy particles it is the most convenient to use the Penning discharge. In this case, the cathodes made of different materials are under the identical conditions even at the change of working discharge modes. Therefore in the device on the basis of the Penning discharge the cathodes of metal-hydride and stainless steel were set. It was detected, that the increase of the temperature gradient of metal-hydride cathode goes down with the increase of discharge current value. The dependence of operating temperatures difference of cathodes from exposure time has shown that the temperature of the metal-hydride cathode is sufficiently lower than the temperature of the stainless steel cathode. Such a softening of the thermal operation conditions of the metal hydride cathode is caused by thermal decomposition of hydride phases. Besides there is the energy flow dissipation of bombarding particles on the protective gas target formed by desorbed hydrogen. The considerable decrease of

  7. Studying the non-thermal plasma jet characteristics and application on bacterial decontamination

    Science.gov (United States)

    Al-rawaf, Ali F.; Fuliful, Fadhil Khaddam; Khalaf, Mohammed K.; Oudah, Husham. K.

    2018-04-01

    Non-thermal atmospheric-pressure plasma jet represents an excellent approach for the decontamination of bacteria. In this paper, we want to improve and characterize a non-thermal plasma jet to employ it in processes of sterilization. The electrical characteristics was studied to describe the discharge of the plasma jet and the development of plasma plume has been characterized as a function of helium flow rate. Optical emission spectroscopy was employed to detect the active species inside the plasma plume. The inactivation efficiency of non-thermal plasma jet was evaluated against Staphylococcus aureus bacteria by measuring the diameter of inhibition zone and the number of surviving cells. The results presented that the plasma plume temperature was lower than 34° C at a flow rate of 4 slm, which will not cause damage to living tissues. The diameter of inhibition zone is directly extended with increased exposure time. We confirmed that the inactivation mechanism was unaffected by UV irradiation. In addition, we concluded that the major reasons for the inactivation process of bacteria is because of the action of the reactive oxygen and nitrogen species which formed from ambient air, while the charged particles played a minor role in the inactivation process.

  8. Thermal plasma synthesis of transition metal nitrides and alloys

    International Nuclear Information System (INIS)

    Ronsheim, P.; Christensen, A.N.; Mazza, A.

    1981-01-01

    Applications of arc plasma processing to high-temperature chemistry of Group V nitrides and Si and Ge alloys are studied. The transition metal nitrides 4f-VN, 4f-NbN, and 4f-TaN are directly synthesized in a dc argon-nitrogen plasma from powders of the metals. A large excess of N 2 is required to form stoichiometric 4f-VN, while the Nb and Ta can only be synthesized with a substoichiometric N content. In a dc argon plasma the alloys V 3 Si, VSi 2 , NbSi 2 , NbGe 2 , Cr 3 Si, and Mo 3 Si are obtained from powder mixtures of the corresponding elements. The compounds are identified by x-ray diffraction patterns and particle shape and size are studied by electron microscopy

  9. Studies of the influence of nonequilibrium plasma thermal exposure on the characteristics of the capillary-porous polymer material

    International Nuclear Information System (INIS)

    Makhotkina, L Yu; Khristoliubova, V I

    2017-01-01

    Capillary-porous materials, which include natural macromolecular tanning material, are exposed to a number of factors during the treatment by a nonequilibrium plasma. Plasma particles exchange the charge and energy with the atoms of the material during the interaction of the plasma with the surface. The results of treatment are desorption of atoms and molecules from the body surface, sputtering and evaporation of material’s particles, changes of the structure and phase state. In real terms during the modification of solids by nonequilibrium low-temperature plasma thermal effect influences the process. The energy supplied from the discharge during the process with low pressure, which is converted into heat, is significantly less than during the atmospheric pressure, but the thermal stability of high-molecular compounds used in the manufacture of materials and products of the tanning industry, is very limited and depends on the duration of the effect of temperature. Even short heating of hydrophilic polymers (proteins) (100-180 °C) causes a change in their properties. It decreases the collagen ability to absorb water vapor, to swell in water, acids, alkalis, and thus decreases their durability. Prolonged heating leads to a deterioration of the physical and mechanical properties. Higher heating temperatures it leads to the polymer degradation. The natural leather temperature during plasma exposure does not rise to a temperature of collagen degradation and does not result in changes of physical phase of the dermis. However, the thermal plasma exposure must be considered, since the high temperatures influence on physical and mechanical properties. (paper)

  10. Investigating the Plasma-Assisted and Thermal Catalytic Dry Methane Reforming for Syngas Production: Process Design, Simulation and Evaluation

    Directory of Open Access Journals (Sweden)

    Evangelos Delikonstantis

    2017-09-01

    Full Text Available The growing surplus of green electricity generated by renewable energy technologies has fueled research towards chemical industry electrification. By adapting power-to-chemical concepts, such as plasma-assisted processes, cheap resources could be converted into fuels and base chemicals. However, the feasibility of those electrified processes at large scale has not been investigated yet. Thus, the current work strives to compare, for first time in the literature, plasma-assisted production of syngas, from CH4 and CO2 (dry methane reforming, with thermal catalytic dry methane reforming. Specifically, both processes are conceptually designed to deliver syngas suitable for methanol synthesis (H2/CO ≥ 2 in mole. The processes are simulated in the Aspen Plus process simulator where different process steps are investigated. Heat integration and equipment cost estimation are performed for the most promising process flow diagrams. Collectively, plasma-assisted dry methane reforming integrated with combined steam/CO2 methane reforming is an effective way to deliver syngas for methanol production. It is more sustainable than combined thermal catalytic dry methane reforming with steam methane reforming, which has also been proposed for syngas production of H2/CO ≥ 2; in the former process, 40% more CO2 is captured, while 38% less H2O is consumed per mol of syngas. Furthermore, the plasma-assisted process is less complex than the thermal catalytic one; it requires higher amount of utilities, but comparable capital investment.

  11. On the influence of dissipative effects on instabilities of differentially-rotating plasmas

    International Nuclear Information System (INIS)

    Lakhin, V. P.; Ilgisonis, V. I.

    2010-01-01

    The stability of differentially-rotating cylindrical plasmas in the axial homogeneous magnetic field is studied in the framework of one-fluid dissipative magnetohydrodynamics. The dispersion relation of small-scale axisymmetric perturbations, taking into account the effects of the plasma thermal stratification, its resistivity and its viscosity, is derived. In the limiting cases of negligible resistivity and of negligible viscosity, the criteria of plasma stability are obtained. It is shown that in the case of small viscosity, the azimuthal flow of resistive plasma in the axial magnetic field is unstable due to the buoyancy effect if both the plasma pressure and its entropy either increase or decrease in the radial direction.

  12. Periodic pulling of the drift instability in a thermal plasma

    International Nuclear Information System (INIS)

    Abrams, R.H. Jr.

    1970-01-01

    The primary objective of this thesis is to show that a mode of oscillation in a plasma can be represented by a van der Pol oscillator. The results of an experiment performed on a drift wave in a Q-machine are interpreted in terms of a mechanism developed by Lashinsky. The mechanism, called periodic pulling, predicts a specific kind of spectrum for certain experimental conditions when a van der Pol oscillator is perturbed by a small signal. The observed spectrum, along with other observations, lends credence to the van der Pol oscillator model of a plasma mode

  13. Non-equilibrium synergistic effects in atmospheric pressure plasmas.

    Science.gov (United States)

    Guo, Heng; Zhang, Xiao-Ning; Chen, Jian; Li, He-Ping; Ostrikov, Kostya Ken

    2018-03-19

    Non-equilibrium is one of the important features of an atmospheric gas discharge plasma. It involves complicated physical-chemical processes and plays a key role in various actual plasma processing. In this report, a novel complete non-equilibrium model is developed to reveal the non-equilibrium synergistic effects for the atmospheric-pressure low-temperature plasmas (AP-LTPs). It combines a thermal-chemical non-equilibrium fluid model for the quasi-neutral plasma region and a simplified sheath model for the electrode sheath region. The free-burning argon arc is selected as a model system because both the electrical-thermal-chemical equilibrium and non-equilibrium regions are involved simultaneously in this arc plasma system. The modeling results indicate for the first time that it is the strong and synergistic interactions among the mass, momentum and energy transfer processes that determine the self-consistent non-equilibrium characteristics of the AP-LTPs. An energy transfer process related to the non-uniform spatial distributions of the electron-to-heavy-particle temperature ratio has also been discovered for the first time. It has a significant influence for self-consistently predicting the transition region between the "hot" and "cold" equilibrium regions of an AP-LTP system. The modeling results would provide an instructive guidance for predicting and possibly controlling the non-equilibrium particle-energy transportation process in various AP-LTPs in future.

  14. Advanced oxidation technology for H2S odor gas using non-thermal plasma

    Science.gov (United States)

    Tao, ZHU; Ruonan, WANG; Wenjing, BIAN; Yang, CHEN; Weidong, JING

    2018-05-01

    Non-thermal plasma technology is a new type of odor treatment processing. We deal with H2S from waste gas emission using non-thermal plasma generated by dielectric barrier discharge. On the basis of two criteria, removal efficiency and absolute removal amount, we deeply investigate the changes in electrical parameters and process parameters, and the reaction process of the influence of ozone on H2S gas removal. The experimental results show that H2S removal efficiency is proportional to the voltage, frequency, power, residence time and energy efficiency, while it is inversely proportional to the initial concentration of H2S gas, and ozone concentration. This study lays the foundations of non-thermal plasma technology for further commercial application.

  15. Critical ionisation velocity effects in astrophysical plasmas

    International Nuclear Information System (INIS)

    Raadu, M.A.

    1979-08-01

    Critical ionisation velocity effects are relevant to astrophysical situations where neutral gas moves through a magnetised plasma. The experimental significance of the critical velocity is well established and the physical basis is now becoming clear. The underlying mechanism depends on the combined effects of electron impact ionisation and electron energisation by collective plasma interactions. For low density plasmas a theory based on a circular process involving electron heating through a modified two stream instability has been developed. Several applications of critical velocity effects to astrophysical plasmas have been discussed in the literature. The importance of the effect in any particular case may be determined from a detailed consideration of energy and momentum balance, using appropriate atomic rate coefficients and taking full account of collective plasma processes. (Auth.)

  16. Effect of magnetic reconnection in stellar plasma

    Science.gov (United States)

    Hammoud, M.; El Eid, M.; Darwish, M.

    2017-06-01

    An important phenomenon in Astrophysics is the process of magnetic reconnection (MGR), which is envisaged to understand the solar flares, coronal mass ejection, interaction of the solar wind with the Earth’s magnetic field (so called geomagnetic storm) and other phenomena. In addition, it plays a role in the formation of stars. MGR involves topological change of a set of magnetic field lines leading to a new equilibrium configuration of lower magnetic energy. The MGR is basically described in the framework of the Maxwell’s equations linked to Navier-Stockes equations. Nevertheless, many details are still not understood. In this paper, we investigate the MGR process in the framework of the Magnetohydrodynamic (MHD) model of a single conducting fluid using a modern powerful computational tool (OpenFOAM). We will show that the MGR process takes place only if resistivity exists. However, despite the high conductivity of the plasma, resistivity becomes effective in a very thin layer generating sharp gradients of the magnetic field, and thus accelerating the reconnection process. The net effect of MGR is that magnetic energy is converted into thermal and kinetic energies leading to heating and acceleration of charged particles. The Sun’s coronal ejection is an example of the MGR process.

  17. Microscopic electrical conductivity of nanodiamonds after thermal and plasma treatments

    Czech Academy of Sciences Publication Activity Database

    Čermák, Jan; Kozak, Halyna; Stehlík, Štěpán; Švrček, V.; Pichot, V.; Spitzer, D.; Kromka, Alexander; Rezek, Bohuslav

    2016-01-01

    Roč. 1, č. 16 (2016), s. 1105-1111 ISSN 2059-8521 R&D Projects: GA ČR GA15-01809S Institutional support: RVO:68378271 Keywords : atomic force microscopy * conductive AFM * diamond * nanoparticles * plasma Subject RIV: BM - Solid Matter Physics ; Magnetism

  18. Inactivation of human pathogenic dermatophytes by non-thermal plasma

    Czech Academy of Sciences Publication Activity Database

    Scholtz, V.; Soušková, H.; Hubka, Vít; Švarcová, M.; Julák, J.

    2015-01-01

    Roč. 119, DEC 2015 (2015), s. 53-58 ISSN 0167-7012 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : Corona discharge * Cometary discharge * Decontamination of surfaces Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.857, year: 2015

  19. Experimental investigation of thermal conduction and related phenomena in a laser heated plasma

    International Nuclear Information System (INIS)

    Gray, D.R.

    1979-02-01

    Thermal conduction in plasmas is of major importance especially in controlled nuclear fusion studies. Direct measurements are rare. When the temperature gradient in a plasma becomes large enough classical thermal conduction (Heat flux q = -kΔT) no longer applies and it is thought that q is limited to some fraction of the free streaming limit qsub(m). The main experiment is the heating of a z-pinch plasma by a fast rising, intense carbon dioxide laser pulse. Electron temperature and density in time and space are diagnosed by ruby laser scattering. The profiles obtained were consistent with a flux limited to approximately 3% of the free streaming limit. Ion acoustic turbulence is observed along the temperature gradient. It is shown that the observed turbulence level is consistent with the heat flux limitation. At electron densities > 10 17 cm -3 backscattered light is observed from the plasma whose growth rate implies that it is Brillouin scattered. (author)

  20. Mechanical effects in a rarified plasma

    International Nuclear Information System (INIS)

    Dubinov, A. E.; Sadovoy, S. A.

    2007-01-01

    A study is made of various mechanical effects that arise in a rarified plasma and set macroscopic solid bodies into motion: the magnetomechanical effect, the mechanical surface effect, the attraction of macrobodies, the levitation of a body in a plasma, and the orientation of a levitating body. Attention is focused on the design and construction of relevant experiments and experimental tests, as well as on the interpretation of the phenomena observed. Possible applications of the mechanical effects in physics and engineering are discussed

  1. Dispersion in a thermal plasma including arbitrary degeneracy and quantum recoil.

    Science.gov (United States)

    Melrose, D B; Mushtaq, A

    2010-11-01

    The longitudinal response function for a thermal electron gas is calculated including two quantum effects exactly, degeneracy, and the quantum recoil. The Fermi-Dirac distribution is expanded in powers of a parameter that is small in the nondegenerate limit and the response function is evaluated in terms of the conventional plasma dispersion function to arbitrary order in this parameter. The infinite sum is performed in terms of polylogarithms in the long-wavelength and quasistatic limits, giving results that apply for arbitrary degeneracy. The results are applied to the dispersion relations for Langmuir waves and to screening, reproducing known results in the nondegenerate and completely degenerate limits, and generalizing them to arbitrary degeneracy.

  2. Mechanical characterization of W-armoured plasma-facing components after thermal fatigue

    International Nuclear Information System (INIS)

    Serret, D; Richou, M; Missirlian, M; Loarer, T

    2011-01-01

    The future fusion device ITER is aimed at demonstrating the scientific and technical feasibility of fusion power. Tens of thousands of W-armoured plasma-facing components (PFCs) will be installed in the vertical targets of the ITER divertor and subjected to a high heat flux. The purpose of this paper is to present the results of mechanical and microstructural characterization of tungsten PFCs after thermal fatigue tests. On each component, Vickers hardness measurements are made. In parallel, the mean grain diameter in the corresponding zone of tungsten material is determined. The empirical Hall-Petch relation was adapted to experimental data. However, due to the plateau effect on recrystallization hardness, this relation does not seem to be relevant once recrystallization is complete: a new approach is proposed for predicting the margin to the tungsten melting onset.

  3. Research on electric and thermal characteristics of plasma torch based on similarity theory

    International Nuclear Information System (INIS)

    Cheng Changming; Tang Deli; Lan Wei

    2007-01-01

    Configuration and working principle of a DC non-transferred plasma torch have been introduced. Based on similarity theory, connections between the electric-thermal characteristics and operational parameter such as flowing gas rate and arc power have been investigated. Calculation and experiment are compared. The results indicate that the calculation results are in agreement with experimental ones. The formulas can be used for plasma torch improvement and optimization. (authors)

  4. Non-thermal Plasma Activates Human Keratinocytes by Stimulation of Antioxidant and Phase II Pathways

    Science.gov (United States)

    Schmidt, Anke; Dietrich, Stephan; Steuer, Anna; Weltmann, Klaus-Dieter; von Woedtke, Thomas; Masur, Kai; Wende, Kristian

    2015-01-01

    Non-thermal atmospheric pressure plasma provides a novel therapeutic opportunity to control redox-based processes, e.g. wound healing, cancer, and inflammatory diseases. By spatial and time-resolved delivery of reactive oxygen and nitrogen species, it allows stimulation or inhibition of cellular processes in biological systems. Our data show that both gene and protein expression is highly affected by non-thermal plasma. Nuclear factor erythroid-related factor 2 (NRF2) and phase II enzyme pathway components were found to act as key controllers orchestrating the cellular response in keratinocytes. Additionally, glutathione metabolism, which is a marker for NRF2-related signaling events, was affected. Among the most robustly increased genes and proteins, heme oxygenase 1, NADPH-quinone oxidoreductase 1, and growth factors were found. The roles of NRF2 targets, investigated by siRNA silencing, revealed that NRF2 acts as an important switch for sensing oxidative stress events. Moreover, the influence of non-thermal plasma on the NRF2 pathway prepares cells against exogenic noxae and increases their resilience against oxidative species. Via paracrine mechanisms, distant cells benefit from cell-cell communication. The finding that non-thermal plasma triggers hormesis-like processes in keratinocytes facilitates the understanding of plasma-tissue interaction and its clinical application. PMID:25589789

  5. Preliminary degradation process study of infectious biological waste in a 5 k W thermal plasma equipment

    International Nuclear Information System (INIS)

    Xochihua S M, M.C.

    1997-01-01

    This work is a preliminary study of infectious biological waste degradation process by thermal plasma and was made in Thermal Plasma Applications Laboratory of Environmental Studies Department of the National Institute of Nuclear Research (ININ). Infectious biological waste degradation process is realized by using samples such polyethylene, cotton, glass, etc., but the present study scope is to analyze polyethylene degradation process with mass and energy balances involved. Degradation method is realized as follow: a polyethylene sample is put in an appropriated crucible localized inside a pyrolysis reactor chamber, the plasma jet is projected to the sample, by the pyrolysis phenomena the sample is degraded into its constitutive particles: carbon and hydrogen. Air was utilized as a recombination gas in order to obtain the higher percent of CO 2 if amount of O 2 is greater in the recombination gas, the CO generation is reduced. The effluent gases of exhaust pyrolysis reactor through are passed through a heat exchanger to get cooled gases, the temperature water used is 15 Centigrade degrees. Finally the gases was tried into absorption tower with water as an absorbent fluid. Thermal plasma degradation process is a very promising technology, but is necessary to develop engineering process area to avail all advantages of thermal plasma. (Author)

  6. Thermal plasma treatment of stormwater sediments: comparison between DC non-transferred and partially transferred arc plasma.

    Science.gov (United States)

    Li, O L; Guo, Y; Chang, J S; Saito, N

    2015-01-01

    The disposal of enormous amount of stormwater sediments becomes an emerging worldwide problem. Stormwater sediments are contaminated by heavy metals, phosphorus, trace organic and hydrocarbons, and cannot be disposed without treatment. Thermal plasma decontamination technology offers a high decomposition rate in a wide range of toxic organic compound and immobilization of heavy metal. In this study, we compared the treatment results between two different modes of thermal plasma: (1) a non-transferred direct current (DC) mode and (2) a partial DC-transferred mode. The reductions of total organic carbon (TOC) were, respectively, 25% and 80% for non-transferred and partially transferred plasma, respectively. Most of the toxic organic compounds were converted majorly to CxHy. In the gaseous emission, the accumulated CxHy, CO, NO and H2S were significantly higher in partially transferred mode than in non-transferred mode. The solid analysis demonstrated that the concentrations of Ca and Fe were enriched by 500% and 40%, respectively. New chemical compositions such as KAlSi3O8, Fe3O4, NaCl and CaSO4 were formed after treatment in partially DC-transferred mode. The power inputs were 1 and 10 kW, respectively, for non-transferred DC mode and a partially DC-transferred mode. With a lower energy input, non-transferred plasma treatment can be used for decontamination of sediments with low TOC and metal concentration. Meanwhile, partially transferred thermal plasma with higher energy input is suitable for treating sediments with high TOC percentage and volatile metal concentration. The organic compounds are converted into valuable gaseous products which can be recycled as an energy source.

  7. Self-consistent Langmuir waves in resonantly driven thermal plasmas

    Science.gov (United States)

    Lindberg, R. R.; Charman, A. E.; Wurtele, J. S.

    2007-12-01

    The longitudinal dynamics of a resonantly driven Langmuir wave are analyzed in the limit that the growth of the electrostatic wave is slow compared to the bounce frequency. Using simple physical arguments, the nonlinear distribution function is shown to be nearly invariant in the canonical particle action, provided both a spatially uniform term and higher-order spatial harmonics are included along with the fundamental in the longitudinal electric field. Requirements of self-consistency with the electrostatic potential yield the basic properties of the nonlinear distribution function, including a frequency shift that agrees closely with driven, electrostatic particle simulations over a range of temperatures. This extends earlier work on nonlinear Langmuir waves by Morales and O'Neil [G. J. Morales and T. M. O'Neil, Phys. Rev. Lett. 28, 417 (1972)] and Dewar [R. L. Dewar, Phys. Plasmas 15, 712 (1972)], and could form the basis of a reduced kinetic treatment of plasma dynamics for accelerator applications or Raman backscatter.

  8. Self-consistent Langmuir waves in resonantly driven thermal plasmas

    International Nuclear Information System (INIS)

    Lindberg, R. R.; Charman, A. E.; Wurtele, J. S.

    2007-01-01

    The longitudinal dynamics of a resonantly driven Langmuir wave are analyzed in the limit that the growth of the electrostatic wave is slow compared to the bounce frequency. Using simple physical arguments, the nonlinear distribution function is shown to be nearly invariant in the canonical particle action, provided both a spatially uniform term and higher-order spatial harmonics are included along with the fundamental in the longitudinal electric field. Requirements of self-consistency with the electrostatic potential yield the basic properties of the nonlinear distribution function, including a frequency shift that agrees closely with driven, electrostatic particle simulations over a range of temperatures. This extends earlier work on nonlinear Langmuir waves by Morales and O'Neil [G. J. Morales and T. M. O'Neil, Phys. Rev. Lett. 28, 417 (1972)] and Dewar [R. L. Dewar, Phys. Plasmas 15, 712 (1972)], and could form the basis of a reduced kinetic treatment of plasma dynamics for accelerator applications or Raman backscatter

  9. Artificial vesicles as an animal cell model for the study of biological application of non-thermal plasma

    International Nuclear Information System (INIS)

    Ki, S H; Park, J K; Sung, C; Lee, C B; Uhm, H; Choi, E H; Baik, K Y

    2016-01-01

    Artificial cell-like model systems can provide information which is hard to obtain with real biological cells. Giant unilamellar vesicles (GUV) containing intra-membrane DNA or OH radical-binding molecules are used to visualize the cytolytic activity of OH radicals. Changes in the GUV membrane are observed by microscopy or flow cytometry as performed for animal cells after non-thermal plasma treatment. The experimental data shows that OH radicals can be detected inside the membrane, although the biological effects are not as significant as for H 2 O 2 . This artificial model system can provide a systemic means to elucidate the complex interactions between biological materials and non-thermal plasma. (paper)

  10. Non thermal plasma surface cleaner and method of use

    KAUST Repository

    Neophytou, Marios

    2017-09-14

    Described herein are plasma generation devices and methods of use of the devices. The devices can be used for the cleaning of various surfaces and/or for inhibiting or preventing the accumulation of particulates, such as dust, or moisture on various surfaces. The devices can be used to remove dust and other particulate contaminants from solar panels and windows, or to avoid or minimize condensation on various surfaces. In an embodiment a plasma generation device is provided. The plasma generation device can comprise: a pair of electrodes (1,2) positioned in association with a surface of a dielectric substrate (3). The pair of electrodes (1,2) can comprise a first electrode (1) and a second electrode (2). The first electrode and second electrode can be of different sizes, one of the electrodes being smaller than the other of the electrodes. The first electrode and second electrode can be separated by a distance and electrically connected to a voltage source (4,5).

  11. Non thermal plasma surface cleaner and method of use

    KAUST Repository

    Neophytou, Marios; Lacoste, Deanna A.; Kirkus, Mindaugas

    2017-01-01

    Described herein are plasma generation devices and methods of use of the devices. The devices can be used for the cleaning of various surfaces and/or for inhibiting or preventing the accumulation of particulates, such as dust, or moisture on various surfaces. The devices can be used to remove dust and other particulate contaminants from solar panels and windows, or to avoid or minimize condensation on various surfaces. In an embodiment a plasma generation device is provided. The plasma generation device can comprise: a pair of electrodes (1,2) positioned in association with a surface of a dielectric substrate (3). The pair of electrodes (1,2) can comprise a first electrode (1) and a second electrode (2). The first electrode and second electrode can be of different sizes, one of the electrodes being smaller than the other of the electrodes. The first electrode and second electrode can be separated by a distance and electrically connected to a voltage source (4,5).

  12. Thermal plasma spheroidization and spray deposition of barium titanate powder and characterization of the plasma sprayable powder

    Energy Technology Data Exchange (ETDEWEB)

    Pakseresht, A.H., E-mail: amirh_pak@yahoo.com [Department of Ceramics, Materials and Energy Research Center, P.O. Box 31787-316, Karaj (Iran, Islamic Republic of); Rahimipour, M.R. [Department of Ceramics, Materials and Energy Research Center, P.O. Box 31787-316, Karaj (Iran, Islamic Republic of); Vaezi, M.R. [Department of Nanotechnology and Advanced Materials, Materials and Energy Research Center, P.O. Box 31787-316, Karaj (Iran, Islamic Republic of); Salehi, M. [Department of Materials Engineering, Isfahan University of Technology, P.O. Box 84156-83111, Isfahan (Iran, Islamic Republic of)

    2016-04-15

    In this paper, atmospheric plasma spray method was used to produce dense plasma sprayable powder and thick barium titanate film. In this regard, the commercially feedstock powders were granulated and spheroidized by the organic binder and the thermal spray process, respectively. Scanning electron microscopy was used to investigate the microstructure of the produced powders and the final deposits. X-ray diffraction was also implemented to characterize phase of the sprayed powder. The results indicated that spheroidized powder had suitable flowability as well as high density. The micro-hardness of the film produced by the sprayed powders was higher than that of the film deposited by the irregular granules. Additionally, relative permittivity of the films was increased by decreasing the defects from 160 to 293 for film deposited using spheroidized powder. The reduction in the relative permittivity of deposits, in comparison with the bulk material, was due to the existence of common defects in the thermal spray process. - Highlights: • We prepare sprayable BaTiO{sub 3} powder with no or less inside voids for plasma spray application for first time. • The sprayable powder has good flow characteristics and high density. • Powder spheroidization via plasma spray improves the hardness and dielectric properties of the deposited film.

  13. Thermal plasma spheroidization and spray deposition of barium titanate powder and characterization of the plasma sprayable powder

    International Nuclear Information System (INIS)

    Pakseresht, A.H.; Rahimipour, M.R.; Vaezi, M.R.; Salehi, M.

    2016-01-01

    In this paper, atmospheric plasma spray method was used to produce dense plasma sprayable powder and thick barium titanate film. In this regard, the commercially feedstock powders were granulated and spheroidized by the organic binder and the thermal spray process, respectively. Scanning electron microscopy was used to investigate the microstructure of the produced powders and the final deposits. X-ray diffraction was also implemented to characterize phase of the sprayed powder. The results indicated that spheroidized powder had suitable flowability as well as high density. The micro-hardness of the film produced by the sprayed powders was higher than that of the film deposited by the irregular granules. Additionally, relative permittivity of the films was increased by decreasing the defects from 160 to 293 for film deposited using spheroidized powder. The reduction in the relative permittivity of deposits, in comparison with the bulk material, was due to the existence of common defects in the thermal spray process. - Highlights: • We prepare sprayable BaTiO_3 powder with no or less inside voids for plasma spray application for first time. • The sprayable powder has good flow characteristics and high density. • Powder spheroidization via plasma spray improves the hardness and dielectric properties of the deposited film.

  14. Thermophysical property calculation in thermal plasmas: status, applications, and availability of basic data

    International Nuclear Information System (INIS)

    Murphy, Anthony B.

    2002-01-01

    The status of the calculation of the composition, thermodynamic properties and transport coefficients of thermal plasmas is reviewed. The availability of the required basic data, i.e., thermodynamic properties of individual species and collision integrals for pairs of species, is surveyed. The calculation of diffusion coefficients, required in mixed-gas plasmas, is discussed, and the advantages of the combined diffusion coefficient formulation are outlined. The specific application of demixing is presented. Recent work addressing the difficulties that arise in calculating the composition and transport coefficients of two-temperature plasmas is briefly reviewed. (author)

  15. Non-thermal plasma destruction of allyl alcohol in waste gas: kinetics and modelling

    Science.gov (United States)

    DeVisscher, A.; Dewulf, J.; Van Durme, J.; Leys, C.; Morent, R.; Van Langenhove, H.

    2008-02-01

    Non-thermal plasma treatment is a promising technique for the destruction of volatile organic compounds in waste gas. A relatively unexplored technique is the atmospheric negative dc multi-pin-to-plate glow discharge. This paper reports experimental results of allyl alcohol degradation and ozone production in this type of plasma. A new model was developed to describe these processes quantitatively. The model contains a detailed chemical degradation scheme, and describes the physics of the plasma by assuming that the fraction of electrons that takes part in chemical reactions is an exponential function of the reduced field. The model captured the experimental kinetic data to less than 2 ppm standard deviation.

  16. Non-thermal plasma destruction of allyl alcohol in waste gas: kinetics and modelling

    International Nuclear Information System (INIS)

    Visscher, A de; Dewulf, J; Durme, J van; Leys, C; Morent, R; Langenhove, H Van

    2008-01-01

    Non-thermal plasma treatment is a promising technique for the destruction of volatile organic compounds in waste gas. A relatively unexplored technique is the atmospheric negative dc multi-pin-to-plate glow discharge. This paper reports experimental results of allyl alcohol degradation and ozone production in this type of plasma. A new model was developed to describe these processes quantitatively. The model contains a detailed chemical degradation scheme, and describes the physics of the plasma by assuming that the fraction of electrons that takes part in chemical reactions is an exponential function of the reduced field. The model captured the experimental kinetic data to less than 2 ppm standard deviation

  17. Aging effects on vertical graphene nanosheets and their thermal stability

    Science.gov (United States)

    Ghosh, S.; Polaki, S. R.; Ajikumar, P. K.; Krishna, N. G.; Kamruddin, M.

    2018-03-01

    The present study investigates environmental aging effects and thermal stability of vertical graphene nanosheets (VGN). Self-organized VGN is synthesized by plasma enhanced chemical vapor deposition and exposed to ambient conditions over 6-month period to examine its aging behavior. A systematic inspection is carried out on morphology, chemical structure, wettability and electrical property by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, water contact angle and four-probe resistivity measurements at regular intervals, respectively. Detailed microscopic and spectroscopic analysis substantiated the retention of graphitic quality and surface chemistry of VGN over the test period. An unchanged sheet resistance and hydrophobicity reveals its electrical and wetting stability over the time, respectively. Thermogravimetric analysis ensures an excellent thermal stability of VGN up to 575 °C in ambient atmosphere. These findings of long-term morphological, structural, wetting, electrical and thermal stability of VGN validate their potential utilization for the next-generation device applications.

  18. Thermal shock problems of bonded structure for plasma facing components

    International Nuclear Information System (INIS)

    Shibui, M.; Kuroda, T.; Kubota, Y.

    1991-01-01

    Thermal shock tests have been performed on W(Re)/Cu and Mo/Cu duplex structures with a particular emphasis on two failure modes: failure on the heated surface and failure near the bonding interface. The results indicate that failure of the duplex structure largely depends on the constraint of thermal strain on the heated surface and on the ductility changes of armour materials. Rapid debonding of the bonding interface may be attributed to the yielding of armour materials. This leads to a residual bending deformation when the armour cools down. Arguments are also presented in this paper on two parameter characterization of the failure of armour materials and on stress distribution near the free edge of the bonding interface. (orig.)

  19. Effects of fueling profiles on plasma transport

    International Nuclear Information System (INIS)

    Houlberg, W.A.; Mense, A.T.; Attenberger, S.E.; Milora, S.L.

    1977-01-01

    The effects of cold particle fueling profiles on particle and energy transport in an ignition sized tokamak plasma are investigated in this study with a one-dimensional, multifluid transport model. A density gradient driven trapped particle microinstability model for plasma transport is used to demonstrate potential effects of fueling profiles on ignition requirements. Important criteria for the development of improved transport models under the conditions of shallow particle fueling profiles are outlined. A discrete pellet fueling model indicates that large fluctuations in density and temperature may occur in the outer regions of the plasma with large, shallowly penetrating pellets, but fluctuations in the pressure profile are small. The hot central core of the plasma remains unaffected by the large fluctuations near the plasma edge

  20. Measurement of thermal plasma jet temperature and velocity by laser light lineshape analysis

    International Nuclear Information System (INIS)

    Snyder, S.C.; Reynolds, L.D.

    1991-01-01

    Two important parameters of thermal plasma jets are kinetic or gas temperatures and flow velocity. Gas temperatures have been traditionally measured using emission spectroscopy, but this method depends on either the generally unrealistic assumption of the existence of local thermodynamic equilibrium (LTE) within the plasma, or the use of various non-LTE or partial LTE models to relate the intensity of the emission lines to the gas temperature. Plasma jet velocities have been measured using laser Doppler velocimetry on particles injected into the plasma. However, this method is intrusive and it is not known how well the particle velocities represent the gas velocity. Recently, plasma jet velocities have been measured from the Doppler shift of laser light scattered by the plasma. In this case, the Doppler shift was determined from the difference in the transmission profile of a high resolution monochromator between red shifted and blue shifted scattered light. A direct approach to measuring localized temperatures and velocities is afforded by high resolution scattered light lineshape measurements. The linewidth of laser light scattered by atoms and ions can be related to the kinetic temperature without LTE assumptions, while a shift in the peak position relative to the incident laser lineshape yields the gas velocity. We report in this paper work underway to measure gas temperatures and velocities in an argon thermal plasma jet using high resolution lineshape analysis of scattered laser light

  1. Departures from thermal equilibrium in a dense Z-pinch plasma

    International Nuclear Information System (INIS)

    Neufeld, C.R.

    1979-01-01

    This paper presents on analysis of several features of the emission spectrum obtained from a dense hydrogen Z-pinch plasma. The spectrum is characterized by an extremely broad H/sub β/ line and by the absence of an emission line at the H/sub b/ wavelength. Comparison with theory shows that the spectrum is inconsistent with the assumption of a thermal or collision-dominated plasma. The assumption of a substantial overpopulation of the atomic-hydrogen excited levels, ascribed to a rising degree of plasma ionization, provides a satisfactory description of the observed spectrum. This result illustrates the difficulty of establishing valid equilibrium criteria for transient plasmas, even in the case of plasma densities as high as 10 19 cm -3

  2. Modulation instability of ion thermal waves in a pair-ion plasma containing charged dust impurities

    International Nuclear Information System (INIS)

    Sabry, R.

    2008-01-01

    Modulation instability of ion thermal waves (ITWs) is investigated in a plasma composed of positive and negative ions as well as a fraction of stationary charged (positive or negative) dust impurities. For this purpose, a linear dispersion relation and a nonlinear Schroedinger equation are derived. The latter admits localized envelope solitary wave solutions of bright (pulses) and dark (holes, voids) type. The envelope soliton depends on the intrinsic plasma parameters. It is found that modulation instability of ITWs is significantly affected by the presence of positively/negatively charged dust grains. The findings of this investigation should be useful in understanding the stable electrostatic wave packet acceleration mechanisms in pair-ion plasma, and also enhances our knowledge on the occurrence of instability associated to the existence of charged dust impurities in pair-ion plasmas. Our results should be of relevance for laboratory plasmas.

  3. Ignition phase and steady-state structures of a non-thermal air plasma

    CERN Document Server

    Lu Xin Pei

    2003-01-01

    An AC-driven, non-thermal, atmospheric pressure air plasma is generated within the gap separating a disc-shaped metal electrode and a water electrode. The ignition phase and the steady-state are studied by a high-speed CCD camera. It is found that the plasma always initiates at the surface of the water electrode. The plasma exhibits different structures depending on the polarity of the water electrode: when the water electrode plays the role of cathode, a relatively wide but visibly dim plasma column is generated. At the maximum driving voltage, the gas temperature is between 800 and 900 K, and the peak current is 67 mA; when the water electrode is anode, the plasma column narrows but increases its light emission. The gas temperature in this case is measured to be in the 1400-1500 K range, and the peak current is 81 mA.

  4. Spin and magnetization effects in plasmas

    International Nuclear Information System (INIS)

    Brodin, G; Marklund, M; Zamanian, J; Stefan, M

    2011-01-01

    Quantum effects in plasmas are of interest for a diverse set of systems, and have thus as a field been revived and attracted a lot of attention from a wide community over the past decade. In models of quantum plasmas, the effects studied mostly are due to the quantum particle dispersion and tunnelling. Such effects can be of importance in dense systems and on short length scales. There are also a number of effects related to spin and statistics. However, up to recently the magnetization effect in plasmas due to the intrinsic electron spin has been largely ignored. The magnetization dynamics of e.g. solids has many important applications, such as components for memory storage, but has also been discussed in more 'proper' plasma environments, such as fusion plasmas. Furthermore, also from a basic science point-of-view the effects of intrinsic spin and gyromagnetic effects are of considerable interest. Here we give a short review of a number of different models for treating magnetization effects in plasmas, with a focus on recent results. In particular, the transition between kinetic models and fluid models is discussed. We also give a number of examples of applications of such theories, as well as an outlook for possible future work.

  5. Air plasma effect on dental disinfection

    International Nuclear Information System (INIS)

    Duarte, S.; Murata, R. M.; Saxena, D.; Kuo, S. P.; Chen, C. Y.; Huang, K. J.; Popovic, S.

    2011-01-01

    A nonthermal low temperature air plasma jet is characterized and applied to study the plasma effects on oral pathogens and biofilms. Experiments were performed on samples of six defined microorganisms' cultures, including those of gram-positive bacteria and fungi, and on a cultivating biofilm sample of Streptococcus mutans UA159. The results show that the plasma jet creates a zone of microbial growth inhibition in each treated sample; the zone increases with the plasma treatment time and expands beyond the entire region directly exposed to the plasma jet. With 30s plasma treatment twice daily during 5 days of biofilm cultivation, its formation was inhibited. The viability of S. mutans cells in the treated biofilms dropped to below the measurable level and the killed bacterial cells concentrated to local regions as manifested by the fluorescence microscopy via the environmental scanning electron microscope. The emission spectroscopy of the jet indicates that its plasma effluent carries an abundance of reactive atomic oxygen, providing catalyst for the observed plasma effect.

  6. Air plasma effect on dental disinfection

    Science.gov (United States)

    Duarte, S.; Kuo, S. P.; Murata, R. M.; Chen, C. Y.; Saxena, D.; Huang, K. J.; Popovic, S.

    2011-07-01

    A nonthermal low temperature air plasma jet is characterized and applied to study the plasma effects on oral pathogens and biofilms. Experiments were performed on samples of six defined microorganisms' cultures, including those of gram-positive bacteria and fungi, and on a cultivating biofilm sample of Streptococcus mutans UA159. The results show that the plasma jet creates a zone of microbial growth inhibition in each treated sample; the zone increases with the plasma treatment time and expands beyond the entire region directly exposed to the plasma jet. With 30s plasma treatment twice daily during 5 days of biofilm cultivation, its formation was inhibited. The viability of S. mutans cells in the treated biofilms dropped to below the measurable level and the killed bacterial cells concentrated to local regions as manifested by the fluorescence microscopy via the environmental scanning electron microscope. The emission spectroscopy of the jet indicates that its plasma effluent carries an abundance of reactive atomic oxygen, providing catalyst for the observed plasma effect.

  7. Air plasma effect on dental disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, S.; Murata, R. M.; Saxena, D. [Department of Basic Sciences and Craniofacial Biology, College of Dentistry, New York University, New York, New York 10010 (United States); Kuo, S. P.; Chen, C. Y.; Huang, K. J. [Department of Electrical and Computer Engineering, Polytechnic Institute of New York University, Brooklyn, New York 11202 (United States); Popovic, S. [Department of Physics, Old Dominion University, Norfolk, Virginia 23529 (United States)

    2011-07-15

    A nonthermal low temperature air plasma jet is characterized and applied to study the plasma effects on oral pathogens and biofilms. Experiments were performed on samples of six defined microorganisms' cultures, including those of gram-positive bacteria and fungi, and on a cultivating biofilm sample of Streptococcus mutans UA159. The results show that the plasma jet creates a zone of microbial growth inhibition in each treated sample; the zone increases with the plasma treatment time and expands beyond the entire region directly exposed to the plasma jet. With 30s plasma treatment twice daily during 5 days of biofilm cultivation, its formation was inhibited. The viability of S. mutans cells in the treated biofilms dropped to below the measurable level and the killed bacterial cells concentrated to local regions as manifested by the fluorescence microscopy via the environmental scanning electron microscope. The emission spectroscopy of the jet indicates that its plasma effluent carries an abundance of reactive atomic oxygen, providing catalyst for the observed plasma effect.

  8. Theoretical approach for plasma series resonance effect in geometrically symmetric dual radio frequency plasma

    International Nuclear Information System (INIS)

    Bora, B.; Bhuyan, H.; Favre, M.; Wyndham, E.; Chuaqui, H.

    2012-01-01

    Plasma series resonance (PSR) effect is well known in geometrically asymmetric capacitively couple radio frequency plasma. However, plasma series resonance effect in geometrically symmetric plasma has not been properly investigated. In this work, a theoretical approach is made to investigate the plasma series resonance effect and its influence on Ohmic and stochastic heating in geometrically symmetric discharge. Electrical asymmetry effect by means of dual frequency voltage waveform is applied to excite the plasma series resonance. The results show considerable variation in heating with phase difference between the voltage waveforms, which may be applicable in controlling the plasma parameters in such plasma.

  9. Spontaneous generation of electromagnetic waves in plasmas with electron thermal flux

    International Nuclear Information System (INIS)

    Okada, Toshio

    1977-01-01

    Spontaneous generation of propagating electromagnetic fields due to a microinstability is investigated for plasmas which convey electron thermal fluxes. The following two cases are examined: 1) Electromagnetic fields spontaneously excited by electrons in a velocity distribution of skewed Maxwellian type. 2) Electromagnetic waves generated by electrons in a velocity distribution which consists of a main part and a high energy part. In this case, the electron thermal flux can be very high. In both cases, induced electromagnetic waves with relatively low frequencies propagate parallel to the direction of Thermal flux. (auth.)

  10. Performance of plasma facing materials under intense thermal loads in tokamaks and stellarators

    Energy Technology Data Exchange (ETDEWEB)

    Linke, J.; Hirai, T.; Roedig, M.; Singheiser, L. [Forschungszentrum Juelich GmbH, EURATOM Association, Juelich (Germany)

    2003-07-01

    Beside quasi-stationary plasma operation, short transient thermal pulses with deposited energy densities in the order of several ten MJm{sup -2} are a serious concern for next step devices, in particular for tokamak devices such as ITER. The most serious of these transient events are plasma disruptions. Here a considerable fraction of the plasma energy is deposited on a localized surface area in the divertor strike zone region; the time scale of these events is typically in the order of 1 ms. In spite of the fact that a dense cloud of ablation vapour will form above the strike zone, only partial shielding of the divertor armour from incident plasma particles will occur. As a consequence, thermal shock induced crack formation, vaporization, surface melting, melt layer ejection, and particle emission induced by brittle destruction processes will limit the lifetime of the components. In addition, dust particles (neutron activated metals or tritium enriched carbon) are a serious concern form a safety point of view. Other transient heat loads which occasionally occur in magnetic confinement experiments such as instabilities in the plasma positioning (vertical displacement events) also may cause irreversible damage to plasma facing components (PFC), particularly to metals such as beryllium and tungsten. Another serious damage to PFCs is due to intense fluxes of 14 MeV neutrons in D-T-burning plasma devices. Integrated neutron fluence of several ten dpa in future thermonuclear fusion reactors will degrade essential physical properties of the components (e.g. thermal conductivity); another serious concern is the embrittlement of the heat sink and the plasma facing materials (PFM). (orig.)

  11. Thermal history of the plasma and high-frequency gravitons

    CERN Document Server

    Giovannini, Massimo

    2009-01-01

    Possible deviations from a radiation-dominated evolution, occurring prior the synthesis of light nuclei, impacted on the spectral energy density of high-frequency gravitons. For a systematic scrutiny of this situation, the $\\Lambda$CDM paradigm must be complemented by (at least two) physical parameters describing, respectively, a threshold frequency and a slope. The supplementary frequency scale sets the lower border of a high-frequency domain where the spectral energy grows with a slope which depends, predominantly, upon the total sound speed of the plasma right after inflation. While the infra-red region of the graviton energy spectrum is nearly scale-invariant, the expected signals for typical frequencies larger than 0.01 nHz are hereby analyzed in a model-independent framework by requiring that the total sound speed of the post-inflationary plasma is smaller than the speed of light. Current (e.g. low-frequency) upper limits on the tensor power spectra (determined from the combined analysis of the three la...

  12. High Temperature Oxidation of Spark Plasma Sintered and Thermally Sprayed FeAl-Based Iron Aluminides

    Czech Academy of Sciences Publication Activity Database

    Haušild, P.; Karlík, M.; Skiba, T.; Sajdl, P.; Dubský, Jiří; Palm, M.

    2012-01-01

    Roč. 122, č. 3 (2012), s. 465-468 ISSN 0587-4246. [International Symposium on Physics of Materials (ISPMA)/12./. Prague, 04.09.2011-08.09.2011] Institutional support: RVO:61389021 Keywords : thermal spraying * plasma sintering Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 0.531, year: 2012

  13. The conversion of the thermal energy of plasma in the SOL of tokamaks

    International Nuclear Information System (INIS)

    Nedospasov, A.V.; Nenova, N.V.

    2008-01-01

    When the plasma expands across the confining magnetic field, a part of its thermal energy is converted to electrical energy. In the SOL of tokamaks, the motion of the plasma across the field due to turbulent processes is accompanied by its departure along the open lines of the magnetic field. The conversion of thermal energy is taken into account in theoretical studies devoted to the physics of plasma in the SOL; however, this conversion is ignored in numerical models, for example, in B2-SOLPS4.0. This paper deals with thermal-to-electrical energy conversion in the SOL of tokamaks. It is demonstrated that the part of the thermal energy subjected to conversion to electrical energy forms an appreciable part of the total energy flowing in the SOL. In ITER, this fraction may be as high as 20-25%. The electrical energy generated in the SOL volume is liberated in the form of Joule heat in a relatively cold plasma in the vicinity of diverter plates or directly on these plates. (letter)

  14. Analysis of the step responses of laminar premixed flames to forcing by non-thermal plasma

    KAUST Repository

    Lacoste, Deanna; Moeck, Jonas P.; Roberts, William L.; Chung, Suk-Ho; Cha, Min

    2016-01-01

    The step responses of lean methane-air flames to non-thermal plasma forcing is reported. The experimental setup consists of an axisymmetric burner, with a nozzle made of a quartz tube. The equivalence ratio is 0.95, allowing stabilization

  15. Expanding thermal plasma chemical vapour deposition of ZnO:Al layers for CIGS solar cells

    NARCIS (Netherlands)

    Sharma, K.; Williams, B.L.; Mittal, A.; Knoops, H.C.M.; Kniknie, B.J.; Bakker, N.J.; Kessels, W.M.M.; Schropp, R.E.I.; Creatore, M.

    2014-01-01

    Aluminium-doped zinc oxide (ZnO:Al) grown by expanding thermal plasma chemical vapour deposition (ETP-CVD) has demonstrated excellent electrical and optical properties, which make it an attractive candidate as a transparent conductive oxide for photovoltaic applications. However, when depositing

  16. The interplay between biological and physical scenarios of bacterial death induced by non-thermal plasma

    Czech Academy of Sciences Publication Activity Database

    Lunov, O.; Zablotskyy, V.; Churpita, O.; Jäger, A.; Polívka, L.; Syková, Eva; Dejneka, A.; Kubinová, Šárka

    2016-01-01

    Roč. 82, mar. (2016), s. 71-83 ISSN 0142-9612 R&D Projects: GA MŠk(CZ) LO1309 Institutional support: RVO:68378041 Keywords : non-thermal plasma * bacteria * cytotoxicity Subject RIV: FP - Other Medical Disciplines Impact factor: 8.402, year: 2016

  17. Chemically different non-thermal plasmas target distinct cell death pathways

    Czech Academy of Sciences Publication Activity Database

    Lunov, O.; Zablotskyy, V.; Chrupina, O.; Lunova, M.; Jirsa, M.; Dejneka, A.; Kubinová, Šárka

    2017-01-01

    Roč. 7, apr (2017), s. 600 ISSN 2045-2322 R&D Projects: GA MŠk(CZ) LO1309 Institutional support: RVO:68378041 Keywords : chemically different * non-thermal plasmas * target distinct cell death pathways Subject RIV: FP - Other Medical Disciplines OBOR OECD: Biophysics Impact factor: 4.259, year: 2016

  18. High throughput deposition of hydrogenated amorphous carbon coatings on rubber with expanding thermal plasma

    NARCIS (Netherlands)

    Pei, Y.T.; Eivani, A.R.; Zaharia, T.; Kazantis, A.V.; Sanden, van de M.C.M.; De Hosson, J.T.M.

    2014-01-01

    Flexible hydrogenated amorphous carbon (a-C:H) thin film coated on rubbers has shown outstanding protection of rubber seals from friction and wear. This work concentrates on the potential advances of expanding thermal plasma (ETP) process for a high throughput deposition of a-C:H thin films in

  19. Thermal instabilities in magnetically confined plasmas: Solar coronal loops

    International Nuclear Information System (INIS)

    Habbal, S.R.; Rosner, R.

    1979-01-01

    The thermal stability of confined solar coronal structures (''loops'') is investigated, following both normal mode and a new, global instability analysis. We demonstrate that: (a) normal mode analysis shows modes with size scales comparable to that of loops to be unstable, but to be strongly affected by the loop boundary conditions; (b) a global analysis, based upon variation of the total loop energy losses and gains, yields loop stability conditions for global modes dependent upon the coronal loop heating process, with magnetically coupled heating processes giving marginal stability. The connection between the present analysis and the minimum flux corona of Hearn is also discussed

  20. Treatment of mixed wastes by thermal plasma discharges; Tratamiento de desechos mixtos por descargas de plasma termico

    Energy Technology Data Exchange (ETDEWEB)

    Diaz A, L.V.; Pacheco S, J.O.; Pacheco P, M.; Monroy G, F.; Emeterio H, M. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: lauradiazarch@yahoo.com.mx

    2007-07-01

    The National Institute of Nuclear Research (ININ) uses an ion exchange resin: IRN 150 (copolymer styrene Divynilbencene) in the TRIGA Mark III reactor to absorb polluted particles with heavy metals and radioactive particles of low level. Once the capacity of filtrate of the resin is exceeded, it is replaced and considered with a mixed waste. This work is based on taking advantage of the advantages of the technique of the thermal plasma in a unique process: (high energy density 105W/cm{sup 3} high enthalpy, high reactivity chemical, high operation temperatures 6000-11500K and quick quenching 106K/s) for the degradation and vitrification of the resin IRN 150. The reactor of plasma is compact and it works to atmospheric pressure and reduced thermal inertia. Therefore, the main parameters involved during the degradation tests and vitrification are: plasma current, voltage, gas flow and distance among the electrodes. The used vitreous matrix, is obtained from a ceramic clay composed by an oxides mixture which are characterized by their good resistance to mechanical impacts and erosion caused by the water. The ceramic clay and the resin IRN 150 were analyzed before the treatment by Scanning Electron Microscopy (MEB), X-ray Diffraction (DRX), Thermal gravimetry (TGA) once vitrified the materials were also analyzed by MEB and DRX. It is obtained as a result that the material more appropriate to be used as vitreous matrix it is a ceramic clay formed by several oxides, being operated the plasma system with a current of 115A, voltage of 25V, flow of the argon gas of 5 l/m and a distance among electrodes of 10mm. With the development of the proposed technology and the material for the vitreous matrix, be rotted to try in a future a great variety of mixed waste. (Author)

  1. Non-thermal plasma-activated water inactivation of food-borne pathogen on fresh produce

    International Nuclear Information System (INIS)

    Ma, Ruonan; Wang, Guomin; Tian, Ying; Wang, Kaile; Zhang, Jue; Fang, Jing

    2015-01-01

    Highlights: • We propose a new approach to treat S. aureus inoculated on strawberries by PAW. • PAW could inactivate S. aureus on strawberries via the Log Reduction results, further confirmed by CLSM and SEM. • The short-lived ROS in PAW are considered the most important agents in inactivation process. • No significant change was found in color, firmness and pH of the PAW treated strawberries. - Abstract: Non-thermal plasma has been widely considered to be an effective method for decontamination of foods. Recently, numerous studies report that plasma-activated water (PAW) also has outstanding antibacterial ability. This study presents the first report on the potential of PAW for the inactivation of Staphylococcus aureus (S. aureus) inoculated on strawberries. PAW treatments achieved a reduction of S. aureus ranging from 1.6 to 2.3 log at day-0 storage, while 1.7 to 3.4 log at day-4 storage. The inactivation efficiency depended on the plasma-activated time for PAW generation and PAW-treated time of strawberries inoculated with S. aureus. LIVE/DEAD staining and scanning electron microscopy results confirm that PAW could damage the bacterial cell wall. Moreover, optical emission spectra and oxidation reduction potential results demonstrate the inactivation is mainly attributed to oxidative stress induced by reactive oxygen species in PAW. In addition, no significant change was found in color, firmness and pH of the PAW treated strawberries. Thus, PAW can be a promising alternative to traditional sanitizers applied in the fresh produce industry.

  2. Non-thermal plasma-activated water inactivation of food-borne pathogen on fresh produce

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ruonan; Wang, Guomin; Tian, Ying; Wang, Kaile [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zhang, Jue, E-mail: zhangjue@pku.edu.cn [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China); Fang, Jing [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China)

    2015-12-30

    Highlights: • We propose a new approach to treat S. aureus inoculated on strawberries by PAW. • PAW could inactivate S. aureus on strawberries via the Log Reduction results, further confirmed by CLSM and SEM. • The short-lived ROS in PAW are considered the most important agents in inactivation process. • No significant change was found in color, firmness and pH of the PAW treated strawberries. - Abstract: Non-thermal plasma has been widely considered to be an effective method for decontamination of foods. Recently, numerous studies report that plasma-activated water (PAW) also has outstanding antibacterial ability. This study presents the first report on the potential of PAW for the inactivation of Staphylococcus aureus (S. aureus) inoculated on strawberries. PAW treatments achieved a reduction of S. aureus ranging from 1.6 to 2.3 log at day-0 storage, while 1.7 to 3.4 log at day-4 storage. The inactivation efficiency depended on the plasma-activated time for PAW generation and PAW-treated time of strawberries inoculated with S. aureus. LIVE/DEAD staining and scanning electron microscopy results confirm that PAW could damage the bacterial cell wall. Moreover, optical emission spectra and oxidation reduction potential results demonstrate the inactivation is mainly attributed to oxidative stress induced by reactive oxygen species in PAW. In addition, no significant change was found in color, firmness and pH of the PAW treated strawberries. Thus, PAW can be a promising alternative to traditional sanitizers applied in the fresh produce industry.

  3. Studies of thermal energy confinement scaling in PDX plasmas: D0 → H+ limiter discharges

    International Nuclear Information System (INIS)

    Kaye, S.M.; Goldston, R.J.; Bell, M.

    1984-06-01

    Experiments were performed on the PDX tokamak to study plasma heating and β scaling with higher power, near-perpendicular neutral beam injection. The data taken during these experiments were analyzed using a time-dependent data interpretation code (TRANSP) to study the transport and thermal confinement scaling over a wide range of plasma parameters. This study focuses on results from experiments with D 0 injection into H + plasmas using graphite rail limiters, a = 40 to 44 cm, R = 143 cm, I/sub p/ = 200 to 480 kA, B/sub T/ = 0.7 to 2.2 T, and typically anti n/sub e/ = 2.5 to 4.2 x 10 13 cm -3 . The results of this study indicate that for both ohmic and neutral beam heated discharges the energy flow out of the plasma is dominated by anomalous electron losses, attributed to electron thermal conduction. The ion conduction losses are well described to electron thermal conduction. The ion conduction losses are well described by neoclassical theory; however, the total ion loss influences the power balance significantly only at high toroidal fields and high plasma currents

  4. The plasma wake field excitation: Recent developments from thermal to quantum regime

    Science.gov (United States)

    Fedele, Renato; Tanjia, Fatema; de Nicola, Sergio; Jovanović, Dušan; Jovanović

    2013-12-01

    To describe the transverse nonlinear and collective self-consistent interaction of a long relativistic electron or positron beam with an unmagnetized plasma, a pair of coupled nonlinear differential equations were proposed by Fedele and Shukla in 1992 (Fedele, R. and Shukla, P. K. 1992a Phys. Rev. A 45, 4045). They were obtained within the quantum-like description provided by the thermal wave model and the theory of plasma wake field excitation. The pair of equations comprises a 2D Schrödinger-like equation for a complex wave function (whose squared modulus is proportional to beam density) and a Poisson-like equation for the plasma wake potential. The dispersion coefficient of the Schrödinger-like equation is proportional to the beam thermal emittance. More recently, Fedele-Shukla equations have been further applied to magnetized plasmas, and solutions were found in the form of nonlinear vortex states and ring solitons. They have been also applied to plasma focusing problems and extended from thermal to quantum regimes. We present here a review of the original approach, and subsequent developments.

  5. Self-organization process of a magnetohydrodynamic plasma in the presence of thermal conduction

    International Nuclear Information System (INIS)

    Zhu, Shao-ping; Horiuchi, Ritoku; Sato, Tetsuya; Watanabe, K.; Hayashi, T.; Todo, Y.; Watanabe, T.H.; Kageyama, A.; Takamaru, H.

    1995-12-01

    A self-organization process of a magnetohydrodynamic(MHD) plasma with a finite thermal conductivity is investigated by means of a three-dimensional MHD simulation. With no thermal conduction an MHD system self-organizes to a non-Taylor's state in which the electric current perpendicular to the magnetic field remains comparable to the parallel electric current. In the presence of thermal conductivity the perpendicular component of electric current and the nonuniformity of thermal pressure generated by driven reconnection tend to be smoothened. Thus, the self-organized state approaches to a force-free minimum energy state under the influence of thermal conduction. Detailed energy conversion processes are also studied to find that the rapid decay of magnetic energy during the self-organization process is caused not only through the ohmic heating, but also through the work done by the j x B force. (author)

  6. Stress hysteresis during thermal cycling of plasma-enhanced chemical vapor deposited silicon oxide films

    Science.gov (United States)

    Thurn, Jeremy; Cook, Robert F.

    2002-02-01

    The mechanical response of plasma-enhanced chemical vapor deposited SiO2 to thermal cycling is examined by substrate curvature measurement and depth-sensing indentation. Film properties of deposition stress and stress hysteresis that accompanied thermal cycling are elucidated, as well as modulus, hardness, and coefficient of thermal expansion. Thermal cycling is shown to result in major plastic deformation of the film and a switch from a compressive to a tensile state of stress; both athermal and thermal components of the net stress alter in different ways during cycling. A mechanism of hydrogen incorporation and release from as-deposited silanol groups is proposed that accounts for the change in film properties and state of stress.

  7. Plasma Reforming of Liquid Hydrocarbon Fuels in Non-Thermal Plasma-Liquid Systems

    Science.gov (United States)

    2010-04-30

    channel with liquid wall in the microporous media under the ultrasound cavitations has shown the following: · The action of the ultrasound field in the...microporous liquid which has a very large ratio of the plasma-liquid contact surface to the plasma volume. As is known the ultrasonic (US) cavitation is a very...2) and it ran over a flat dielectric surface of the magnetostrictive transmitter (5) which produced ultrasonic (US) cavitations , so the discharge

  8. Effects of charge depletion in dusty plasmas

    International Nuclear Information System (INIS)

    Goertz, Imke; Greiner, Franko; Piel, Alexander

    2011-01-01

    The charge reduction effect is studied in dense dust clouds. The saturation currents of Langmuir probes are used to derive the density of ions and electrons, which are calibrated with the plasma oscillation method. The plasma potential inside the dust cloud is measured with an emissive probe, which also yields the floating potential in a heated nonemitting mode. The presence of the dust also affects the density and the plasma potential of the ambient plasma. The ion densities inside the dust cloud and in the ambient plasma are found equal, while the electron density is reduced inside the dust cloud. The measured potentials are compared with current models. Inclusion of the bi-Maxwellian distribution of the electrons leads to an improved description in the limit of low dust density. The strong increase of the floating and cloud potential for high dust density, predicted by the constant ion density model, is not confirmed.

  9. Johnson noise and the thermal Casimir effect

    International Nuclear Information System (INIS)

    Bimonte, Giuseppe

    2007-01-01

    We study the thermal interaction between two nearby thin metallic wires, at finite temperature. It is shown that the Johnson currents in the wires give rise, via inductive coupling, to a repulsive force between them. This thermal interaction exhibits all the puzzling features found recently in the thermal Casimir effect for lossy metallic plates, suggesting that the physical origin of the difficulties encountered in the Casimir problem resides in the inductive coupling between the Johnson currents inside the plates. We show that in our simple model all puzzles are resolved if account is taken of capacitive effects associated with the end points of the wires. Our findings suggest that capacitive finite-size effects may play an important role in the resolution of the analogous problems met in the thermal Casimir effect

  10. Characteristics and Thermal Efficiency of a Non-transferred DC Plasma Spraying Torch Under Low Pressure

    International Nuclear Information System (INIS)

    Bao Shicong; Ye Minyou; Zhang Xiaodong; Guo Wenkang; Xu Ping

    2008-01-01

    Current-voltage (I-V) characteristics of a non-transferred DC arc plasma spray torch operated in argon at vacuum are reported. The arc voltage is of negative characteristics for a current below 200 A, flat for a current between 200 A to 250 A and positive for a current beyond 250 A. The voltage increases slowly with the increase in carrier gas of arc. The rate of change in voltage with currents is about 3∼4 V/100 A at a gas flow rate of about 1∼1.5 V/10 standard liter per minute (slpm). The I-V characteristics of the DC plasma torch are of a shape of hyperbola. Arc power increases with the argon flow rate, and the thermal efficiency of the torch acts in a similar way. The thermal efficiency of the non-transferred DC plasmatron is about 65∼78%. (low temperature plasma)

  11. Thermal Bridge Effects in Walls Separating Rowhouses

    DEFF Research Database (Denmark)

    Rose, Jørgen

    1997-01-01

    In this report the thermal bridge effects at internal wall/roof junctions in rowhouses are evaluated. The analysis is performed using a numerical calculation programme, and different solutions are evaluated with respect to extra heat loss and internal surface temperatures.......In this report the thermal bridge effects at internal wall/roof junctions in rowhouses are evaluated. The analysis is performed using a numerical calculation programme, and different solutions are evaluated with respect to extra heat loss and internal surface temperatures....

  12. Finite element thermal study of the Linac4 plasma generator

    International Nuclear Information System (INIS)

    Faircloth, D.; Kronberger, M.; Kuechler, D.; Lettry, J.; Scrivens, R.

    2010-01-01

    The temperature distribution and heat flow at equilibrium of the plasma generator of the rf-powered noncesiated Linac4 H - ion source have been studied with a finite element model. It is shown that the equilibrium temperatures obtained in the Linac4 nominal operation mode (100 kW rf power, 2 Hz repetition rate, and 0.4 ms pulse duration) are within material specifications except for the magnet cage, where a redesign may be necessary. To assess the upgrade of the Linac4 source for operation in the high-power operation mode of the Superconducting Proton Linac (SPL), an extrapolation of the heat load toward 100 kW rf power, 50 Hz repetition rate, and 0.4 ms pulse duration has been performed. The results indicate that a significant improvement of the source cooling is required to allow for operation in the high-power mode of SPL.

  13. Finite element thermal study of the Linac4 plasma generator

    Energy Technology Data Exchange (ETDEWEB)

    Faircloth, D. [STFC, Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX (United Kingdom); Kronberger, M.; Kuechler, D.; Lettry, J.; Scrivens, R. [BE-ABP, Hadron Sources and Linacs, CERN, CH-1211 Geneva (Switzerland)

    2010-02-15

    The temperature distribution and heat flow at equilibrium of the plasma generator of the rf-powered noncesiated Linac4 H{sup -} ion source have been studied with a finite element model. It is shown that the equilibrium temperatures obtained in the Linac4 nominal operation mode (100 kW rf power, 2 Hz repetition rate, and 0.4 ms pulse duration) are within material specifications except for the magnet cage, where a redesign may be necessary. To assess the upgrade of the Linac4 source for operation in the high-power operation mode of the Superconducting Proton Linac (SPL), an extrapolation of the heat load toward 100 kW rf power, 50 Hz repetition rate, and 0.4 ms pulse duration has been performed. The results indicate that a significant improvement of the source cooling is required to allow for operation in the high-power mode of SPL.

  14. Finite Element Thermal Study of the Linac4 Plasma Generatora

    CERN Document Server

    Faircloth, D; Kuchler, D; Lettry, L; Scrivens, R; CERN. Geneva. BE Department

    2010-01-01

    The temperature distribution and heat flow at equilibrium of the plasma generator of the RF-powered non-cesiated Linac4 H- ion source have been studied with a finite element model. It is shown that the equilibrium temperatures obtained in the Linac4 nominal operation mode (100 kW RF power, 2 Hz, 0.4 ms pulse duration) are within material specifications except for the magnet cage, where a redesign may be necessary. To assess the upgrade of the Linac4 source for operation in the high-power operation mode of SPL, an extrapolation of the heat load towards 100 kW RF power, 50 Hz repetition rate and 0.4 ms pulse duration has been performed. The results indicate that a significant improvement of the source cooling is required to allow for operation in HP-SPL.

  15. Half bridge resonant converter for ignition of thermal plasmas

    International Nuclear Information System (INIS)

    Pena E, L.

    1997-01-01

    In this work the background, design, implementation and performance of a half bridge resonant converter (HBRC) used as an electronic ignition system for arc plasma torch generation is presented. The significance of the design lies in its simplicity, versatility and low cost. The system operates like a high voltage supply attached to electrodes before gaseous breakdown and like open circuit when electric arc is established. Resonant converter is implemented with a high voltage and high speed power driver intended for control the power MOSFET transistors connected in half bridge topology with L C load. The HBRC operates besides interference into domestic electric supply line (120 V, 60 Hz) as well electric measurement devices. Advantages and limitations of the converter are reviewed. Experimental impedance variation in the medium as a function of frequency operation and some experiences in striking arcs are also presented. (Author)

  16. Super-Gaussian transport theory and the field-generating thermal instability in laser–plasmas

    International Nuclear Information System (INIS)

    Bissell, J J; Ridgers, C P; Kingham, R J

    2013-01-01

    Inverse bremsstrahlung (IB) heating is known to distort the electron distribution function in laser–plasmas from a Gaussian towards a super-Gaussian, thereby modifying the equations of classical transport theory (Ridgers et al 2008 Phys. Plasmas 15 092311). Here we explore these modified equations, demonstrating that super-Gaussian effects both suppress traditional transport processes, while simultaneously introducing new effects, such as isothermal (anomalous Nernst) magnetic field advection up gradients in the electron number density n e , which we associate with a novel heat-flow q n ∝∇n e . Suppression of classical phenomena is shown to be most pronounced in the limit of low Hall-parameter χ, in which case the Nernst effect is reduced by a factor of five, the ∇T e × ∇n e field generation mechanism by ∼30% (where T e is the electron temperature), and the diffusive and Righi–Leduc heat-flows by ∼80 and ∼90% respectively. The new isothermal field advection phenomenon and associated density-gradient driven heat-flux q n are checked against kinetic simulation using the Vlasov–Fokker–Planck code impact, and interpreted in relation to the underlying super-Gaussian distribution through simplified kinetic analysis. Given such strong inhibition of transport at low χ, we consider the impact of IB on the seeding and evolution of magnetic fields (in otherwise un-magnetized conditions) by examining the well-known field-generating thermal instability in the light of super-Gaussian transport theory (Tidman and Shanny 1974 Phys. Fluids 12 1207). Estimates based on conditions in an inertial confinement fusion (ICF) hohlraum suggest that super-Gaussian effects can reduce the growth-rate of the instability by ≳80%. This result may be important for ICF experiments, since by increasing the strength of IB heating it would appear possible to inhibit the spontaneous generation of large magnetic fields. (paper)

  17. Super-Gaussian transport theory and the field-generating thermal instability in laser-plasmas

    Science.gov (United States)

    Bissell, J. J.; Ridgers, C. P.; Kingham, R. J.

    2013-02-01

    Inverse bremsstrahlung (IB) heating is known to distort the electron distribution function in laser-plasmas from a Gaussian towards a super-Gaussian, thereby modifying the equations of classical transport theory (Ridgers et al 2008 Phys. Plasmas 15 092311). Here we explore these modified equations, demonstrating that super-Gaussian effects both suppress traditional transport processes, while simultaneously introducing new effects, such as isothermal (anomalous Nernst) magnetic field advection up gradients in the electron number density ne, which we associate with a novel heat-flow qn∝∇ne. Suppression of classical phenomena is shown to be most pronounced in the limit of low Hall-parameter χ, in which case the Nernst effect is reduced by a factor of five, the ∇Te × ∇ne field generation mechanism by ˜30% (where Te is the electron temperature), and the diffusive and Righi-Leduc heat-flows by ˜80 and ˜90% respectively. The new isothermal field advection phenomenon and associated density-gradient driven heat-flux qn are checked against kinetic simulation using the Vlasov-Fokker-Planck code impact, and interpreted in relation to the underlying super-Gaussian distribution through simplified kinetic analysis. Given such strong inhibition of transport at low χ, we consider the impact of IB on the seeding and evolution of magnetic fields (in otherwise un-magnetized conditions) by examining the well-known field-generating thermal instability in the light of super-Gaussian transport theory (Tidman and Shanny 1974 Phys. Fluids 12 1207). Estimates based on conditions in an inertial confinement fusion (ICF) hohlraum suggest that super-Gaussian effects can reduce the growth-rate of the instability by ≳80%. This result may be important for ICF experiments, since by increasing the strength of IB heating it would appear possible to inhibit the spontaneous generation of large magnetic fields.

  18. Thermalization of mini-jets in a quark–gluon plasma

    Energy Technology Data Exchange (ETDEWEB)

    Iancu, Edmond, E-mail: edmond.iancu@cea.fr; Wu, Bin, E-mail: bin.wu.phys@gmail.com [Institut de Physique Théorique, CEA Saclay, CNRS UMR 3681, F-91191 Gif-sur-Yvette (France); Department of Physics, The Ohio State University, Columbus, OH 43210 (United States)

    2016-12-15

    We present the complete physical picture for the evolution of a high-energy jet propagating through a weakly-coupled quark-gluon plasma (QGP) by analytical and numerical investigation of thermalization of the soft components of the jet. Our results support the following physical picture: the leading particle emits a significant number of mini-jets which promptly evolve via multiple branching and thus degrade into a myriad of soft gluons, with energies of the order of the medium temperature T. Via elastic collisions with the medium constituents, these soft gluons relax to local thermal equilibrium with the plasma over a time scale which is considerably shorter than the typical lifetime of the mini-jet. The thermalized gluons form a tail which lags behind the hard components of the jet. Together with the background QGP, they behave hydrodynamically.

  19. Novel fragmentation model for pulverized coal particles gasification in low temperature air thermal plasma

    Directory of Open Access Journals (Sweden)

    Jovanović Rastko D.

    2016-01-01

    Full Text Available New system for start-up and flame support based on coal gasification by low temperature air thermal plasma is planned to supplement current heavy oil system in Serbian thermal power plants in order to decrease air pollutions emission and operational costs. Locally introduced plasma thermal energy heats up and ignites entrained coal particles, thus starting chain process which releases heat energy from gasified coal particles inside burner channel. Important stages during particle combustion, such as particle devolatilisation and char combustion, are described with satisfying accuracy in existing commercial CFD codes that are extensively used as powerful tool for pulverized coal combustion and gasification modeling. However, during plasma coal gasification, high plasma temperature induces strong thermal stresses inside interacting coal particles. These stresses lead to “thermal shock” and extensive particle fragmentation during which coal particles with initial size of 50-100 m disintegrate into fragments of at most 5-10 m. This intensifies volatile release by a factor 3-4 and substantially accelerates the oxidation of combustible matter. Particle fragmentation, due to its small size and thus limited influence on combustion process is commonly neglected in modelling. The main focus of this work is to suggest novel approach to pulverized coal gasification under high temperature conditions and to implement it into commercial comprehensive code ANSYS FLUENT 14.0. Proposed model was validated against experimental data obtained in newly built pilot scale D.C plasma burner test facility. Newly developed model showed very good agreement with experimental results with relative error less than 10%, while the standard built-in gasification model had error up to 25%.

  20. Non-thermal plasmas for non-catalytic and catalytic VOC abatement

    International Nuclear Information System (INIS)

    Vandenbroucke, Arne M.; Morent, Rino; De Geyter, Nathalie; Leys, Christophe

    2011-01-01

    Highlights: → We review the current status of catalytic and non-catalytic VOC abatement based on a vast number of research papers. → The underlying mechanisms of plasma-catalysis for VOC abatement are discussed. → Critical process parameters that determine the influent are discussed and compared. - Abstract: This paper reviews recent achievements and the current status of non-thermal plasma (NTP) technology for the abatement of volatile organic compounds (VOCs). Many reactor configurations have been developed to generate a NTP at atmospheric pressure. Therefore in this review article, the principles of generating NTPs are outlined. Further on, this paper is divided in two equally important parts: plasma-alone and plasma-catalytic systems. Combination of NTP with heterogeneous catalysis has attracted increased attention in order to overcome the weaknesses of plasma-alone systems. An overview is given of the present understanding of the mechanisms involved in plasma-catalytic processes. In both parts (plasma-alone systems and plasma-catalysis), literature on the abatement of VOCs is reviewed in close detail. Special attention is given to the influence of critical process parameters on the removal process.

  1. A new maser effect in plasma turbulence

    International Nuclear Information System (INIS)

    Nambu, M.

    1983-01-01

    The present state of understanding of a new maser effect is reviewed. The new maser effect, the idea that the resonant electrons in a turbulent plasma can radiate amplified electromagnetic radiation, does not require population inversion of electrons. The new maser effect always coexists with Landau (or cyclotron) damping; thus it is a fundamental effect in plasma turbulence. In nuclear fusion, magnetic confinement will be at a disadvantage due to the enhanced radiation losses in the long wave length region, while inertial confinement will be improved by the laser effect in the X-ray region. (author)

  2. Thermal Conductivity and Erosion Durability of Composite Two-Phase Air Plasma Sprayed Thermal Barrier Coatings

    Science.gov (United States)

    Schmitt, Michael P.; Rai, Amarendra K.; Zhu, Dongming; Dorfman, Mitchell R.; Wolfe, Douglas E.

    2015-01-01

    To enhance efficiency of gas turbines, new thermal barrier coatings (TBCs) must be designed which improve upon the thermal stability limit of 7 wt% yttria stabilized zirconia (7YSZ), approximately 1200 C. This tenant has led to the development of new TBC materials and microstructures capable of improved high temperature performance. This study focused on increasing the erosion durability of cubic zirconia based TBCs, traditionally less durable than the metastable t' zirconia based TBCs. Composite TBC microstructures composed of a low thermal conductivity/high temperature stable cubic Low-k matrix phase and a durable t' Low-k secondary phase were deposited via APS. Monolithic coatings composed of cubic Low-k and t' Low-k were also deposited, in addition to a 7YSZ benchmark. The thermal conductivity and erosion durability were then measured and it was found that both of the Low-k materials have significantly reduced thermal conductivities, with monolithic t' Low-k and cubic Low-k improving upon 7YSZ by approximately 13 and approximately 25%, respectively. The 40 wt% t' Low-k composite (40 wt% t' Low-k - 60 wt% cubic Low-k) showed a approximately 22% reduction in thermal conductivity over 7YSZ, indicating even at high levels, the t' Low-k secondary phase had a minimal impact on thermal in the composite coating. It was observed that a mere 20 wt% t' Low-k phase addition can reduce the erosion of a cubic Low-k matrix phase composite coating by over 37%. Various mixing rules were then investigated to assess this non-linear composite behavior and suggestions were made to further improve erosion durability.

  3. Magnetic Field Effects on Plasma Plumes

    Science.gov (United States)

    Ebersohn, F.; Shebalin, J.; Girimaji, S.; Staack, D.

    2012-01-01

    Here, we will discuss our numerical studies of plasma jets and loops, of basic interest for plasma propulsion and plasma astrophysics. Space plasma propulsion systems require strong guiding magnetic fields known as magnetic nozzles to control plasma flow and produce thrust. Propulsion methods currently being developed that require magnetic nozzles include the VAriable Specific Impulse Magnetoplasma Rocket (VASIMR) [1] and magnetoplasmadynamic thrusters. Magnetic nozzles are functionally similar to de Laval nozzles, but are inherently more complex due to electromagnetic field interactions. The two crucial physical phenomenon are thrust production and plasma detachment. Thrust production encompasses the energy conversion within the nozzle and momentum transfer to a spacecraft. Plasma detachment through magnetic reconnection addresses the problem of the fluid separating efficiently from the magnetic field lines to produce maximum thrust. Plasma jets similar to those of VASIMR will be studied with particular interest in dual jet configurations, which begin as a plasma loops between two nozzles. This research strives to fulfill a need for computational study of these systems and should culminate with a greater understanding of the crucial physics of magnetic nozzles with dual jet plasma thrusters, as well as astrophysics problems such as magnetic reconnection and dynamics of coronal loops.[2] To study this problem a novel, hybrid kinetic theory and single fluid magnetohydrodynamic (MHD) solver known as the Magneto-Gas Kinetic Method is used.[3] The solver is comprised of a "hydrodynamic" portion based on the Gas Kinetic Method and a "magnetic" portion that accounts for the electromagnetic behaviour of the fluid through source terms based on the resistive MHD equations. This method is being further developed to include additional physics such as the Hall effect. Here, we will discuss the current level of code development, as well as numerical simulation results

  4. Shukla-Spatschek diffusion effects on surface plasma waves in astrophysical turbulent plasmas

    Science.gov (United States)

    Lee, Myoung-Jae; Jung, Young-Dae

    2017-02-01

    The effects of Shukla-Spatschek turbulent diffusion on a temporal mode of surface waves propagating at the interface of an astrophysical turbulent plasma are investigated. The damping rates for high and low modes of surface wave are kinetically derived by employing the Vlasov-Poisson equation and the specular reflection boundary condition. We found that the diffusion caused by the fluctuating electric fields leads to damping for both high and low modes of surface waves. The high-mode damping is enhanced with an increase of the wavenumber and the diffusion coefficient, but suppressed by an increase of electron thermal energy. By contrast, the low-mode damping is suppressed as the wavenumber and the thermal energy increase although it is enhanced as the diffusion increases. The variation of the damping rate due to the Shukla-Spatschek turbulent diffusion is also discussed.

  5. On the propagation of hydromagnetic waves in a plasma of thermal and suprathermal components

    Science.gov (United States)

    Kumar, Nagendra; Sikka, Himanshu

    2007-12-01

    The propagation of MHD waves is studied when two ideal fluids, thermal and suprathermal gases, coupled by magnetic field are moving with the steady flow velocity. The fluids move independently in a direction perpendicular to the magnetic field but gets coupled along the field. Due to the presence of flow in suprathermal and thermal fluids there appears forward and backward waves. All the forward and backward modes propagate in such a way that their rate of change of phase speed with the thermal Mach number is same. It is also found that besides the usual hydromagnetic modes there appears a suprathermal mode which propagates with faster speed. Surface waves are also examined on an interface formed with composite plasma (suprathermal and thermal gases) on one side and the other is a non-magnetized plasma. In this case, the modes obtained are two or three depending on whether the sound velocity in thermal gas is equal to or greater than the sound velocity in suprathermal gas. The results lead to the conclusion that the interaction of thermal and suprathermal components may lead to the occurrence of an additional mode called suprathermal mode whose phase velocity is higher than all the other modes.

  6. Estimation of the thermal diffusion coefficient in fusion plasmas taking frequency measurement uncertainties into account

    International Nuclear Information System (INIS)

    Van Berkel, M; Hogeweij, G M D; Van den Brand, H; De Baar, M R; Zwart, H J; Vandersteen, G

    2014-01-01

    In this paper, the estimation of the thermal diffusivity from perturbative experiments in fusion plasmas is discussed. The measurements used to estimate the thermal diffusivity suffer from stochastic noise. Accurate estimation of the thermal diffusivity should take this into account. It will be shown that formulas found in the literature often result in a thermal diffusivity that has a bias (a difference between the estimated value and the actual value that remains even if more measurements are added) or have an unnecessarily large uncertainty. This will be shown by modeling a plasma using only diffusion as heat transport mechanism and measurement noise based on ASDEX Upgrade measurements. The Fourier coefficients of a temperature perturbation will exhibit noise from the circular complex normal distribution (CCND). Based on Fourier coefficients distributed according to a CCND, it is shown that the resulting probability density function of the thermal diffusivity is an inverse non-central chi-squared distribution. The thermal diffusivity that is found by sampling this distribution will always be biased, and averaging of multiple estimated diffusivities will not necessarily improve the estimation. Confidence bounds are constructed to illustrate the uncertainty in the diffusivity using several formulas that are equivalent in the noiseless case. Finally, a different method of averaging, that reduces the uncertainty significantly, is suggested. The methodology is also extended to the case where damping is included, and it is explained how to include the cylindrical geometry. (paper)

  7. Effects of plasma disruption events on ITER first wall materials

    International Nuclear Information System (INIS)

    Cardella, A.; Gorenflo, H.; Lodato, A.; Ioki, K.; Raffray, R.

    2000-01-01

    In ITER, plasma disruption events may occur producing large fast thermal transients on plasma facing materials. Particularly important for the integrity of the first wall (FW) are relatively 'long' duration off-normal events such as plasma vertical displacement events (VDE) and runaway electrons (RE). An analytical methodology has been developed to specifically assess the effect of these events on FW plasma facing materials. For the typical energy densities and event duration expected for the primary and baffle FW, some melting and evaporation of the FW armor will occur without the beneficial effect of vapor shielding, and the metallic heat sink may also be damaged due to over-heating. The method is able to calculate the amount of melted and evaporated material, taking into account the evolution of the evaporated and melted layer and to evaluate possible effects of local temporary loss of cooling. The method has been used to analyze the effects of VDE and RE events for ITER, to study recent disruption simulation experiments and to benchmark experimental and analytical results

  8. Non-thermal plasma exhaust aftertreatment: Are all plasmas the same?

    Energy Technology Data Exchange (ETDEWEB)

    Whealton, J.H.; Hanson, G.R.; Storey, J.M.; Raridon, R.J.; Armfield, J.S.; Bigelow, T.S.; Graves, R.L. [Oak Ridge National Lab., TN (United States)

    1997-12-31

    The authors describe initial experiments employing 5.5 GHz pulsed microwave power, which should result in enhanced chemistry compared to present state-of-the-art plasma aftertreatments by; reducing plasma electric field shielding, increasing availability of atomic nitrogen, exploiting surface charging of dielectrics, avoiding (low field) threshold initiated discharges, and achieving a higher high energy tail on the electron distribution function. As an example, the authors decided to test for NO reduction in N{sub 2}. While this reaction is not a complete description of the exhaust issues by any means, they thought it would demonstrate the technology proposed.

  9. Effective Ohm's law for a magnetohydrodynamic plasma

    International Nuclear Information System (INIS)

    Kayukawa, Naoyuki; Oikawa, Shunichi; Aoki, Yoshiyuki

    1991-01-01

    Considering that the electrical conductivity of a thermally equilibrium MHD plasma is a strong non-linear function of the gas temperature, the authors first pointed out that the statistically averaged conductivity should be evaluated by the mean temperature as =(1+G)σ( ), where G is given by the third order Taylor expansion with respect to the temperature fluctuation T- and is always positive. Next, in order to obtain a statistically averaged Ohm's law for a turbulent plasma, the correlation (σ'E'> between the conductivity and the electric field fluctuations has been numerically investigated for a plasma with a 1/7th-power average temperature distribution and layered one-dimensional fluctuation between parallel electrodes. It was shown that the correlation is always negative and the averaged current density as well as the plasma resistance is to be corrected appreciably from the values based on the mean temperature. Finally, it was shown that the correction factor / can be evaluated approximately by a 4th-order polynomial of the relative rms temperature fluctuation √ 2 >/ and the relationship is practically insensitive to the variation of the electrode temperature, the boundary-layer thickness and also to the spatial distribution of the fluctuation amplitudes. (author)

  10. Effect of Equilibrium Flow on Plasma Parameters

    International Nuclear Information System (INIS)

    Mukhopadhyay, S.; Lahiri, S.; Sakanaka, P.H.; Dasgupta, B.

    2003-01-01

    The transition to high confinement modes have been identified with the occurrence of strong shear flow near the plasma boundary. Plasma flow has also been associated with various instabilities, heating and other physical processes. As a result, it has become very important to study the effect of such flows on various plasma parameters. In this paper, we present the numerical solution of plasma equilibrium with incompressible toroidal and poloidal flows in several magnetic confinement configurations including tokamaks. The code, which was reported in the last conference, has been used to solve the problem in both circular and D-shaped devices. A parametric study on the generation of shear flow due to radial electric fields has been carried out. Through this study, it has been possible to generate plasma equilibria having sharp pressure gradients which are remarkably close to those reported in various H-mode experiments. The effects of flow on reverse shear equilibria and on the position of the magnetic axis has been studied. Finally, a detailed study has been carried out to understand the effect of flows on important plasma parameters, such as the poloidal flux function, β, energy confinement time

  11. Effects of pressure anisotropy on plasma transport

    International Nuclear Information System (INIS)

    Zawaideh, E.; Najmabadi, F.; Conn, R.W.

    1986-03-01

    In a recent paper a new set of generalized two-field equations is derived which describes plasma transport along the field lines of a space and time dependent magnetic field. These equations are valid for collisional to weakly collisional plasmas; they reduce to the conventional fluid equations of Braginskii for highly collisional plasmas. An important feature of these equations is that the anisotropy in the ion pressure is explicitly included. In this paper, these generalized transport equations are applied to a model problem of plasma flow through a magnetic mirror field. The profiles of the plasma parameters (density, flow speed, and pressures) are numerically calculated for plasma in different collisionality regimes. These profiles are explained by examining the competing terms in the transport equation. The pressure anisotropy is found to profoundly impact the plasma flow behavior. As a result, the new generalized equations predict flow behavior more accurately than the conventional transport equations. A large density and pressure drop is predicted as the flow passes through a magnetic mirror. Further, the new equations uniquely predict oscillations in the density profile, an effect missing in results from the conventional equations

  12. Validity of Saha's equation of thermal ionization for negatively charged spherical particles in complex plasmas in thermal equilibrium

    International Nuclear Information System (INIS)

    Sodha, M. S.; Mishra, S. K.

    2011-01-01

    The authors have discussed the validity of Saha's equation for the charging of negatively charged spherical particles in a complex plasma in thermal equilibrium, even when the tunneling of the electrons, through the potential energy barrier surrounding the particle is considered. It is seen that the validity requires the probability of tunneling of an electron through the potential energy barrier surrounding the particle to be independent of the direction (inside to outside and vice versa) or in other words the Born's approximation should be valid.

  13. Characteristics of ceramic oxide nanoparticles synthesized using radio frequency produced thermal plasma

    International Nuclear Information System (INIS)

    Dhamale, Gayatri D.; Mathe, V.L.; Bhoraskar, S.V.; Ghorui, S.

    2015-01-01

    Thermal plasma devices with their unique processing capabilities due to extremely high temperature and steep temperature gradient play an important role in synthesis of ultrafine powders in the range of 100nm or less. High temperature gas phase synthesis in Radio Frequency (RF) thermal plasma reactor is an attractive route for mass production of refractory nanoparticles, especially in the case of rare earth oxides. Here we report synthesis of Yttrium Oxide (Y_2O_3), Neodymium Oxide (Nd_2O_3) and Aluminum Oxide (Al_2O_3) in an inductively coupled radio frequency thermal plasma reactor. Synthesized nanoparticles find wide application in various fields like gate dielectrics, photocatalytic applications, laser devices and photonics. Nano sized Yttrium oxide, Neodymium Oxide and Aluminum oxide powders were separately synthesized in an RF plasma reactor starting with micron sized irregular shaped precursor powders. The system was operated at 3MHz in atmospheric pressure at different power levels. Synthesized powders were scrapped out from different deposition locations inside the reactor and characterized for their phase, morphology, particle size, crystallinity and other characteristic features. Highly crystalline nature of the synthesized particles, narrow size distribution, location dependent phase formation, and distinct variation in the inherent defect states compared to the bulk are some of the important characteristic features observed

  14. Energy and costs scoping study for plasma pyrolysis thermal processing system

    International Nuclear Information System (INIS)

    Sherick, K.E.; Findley, J.E.

    1992-01-01

    The purpose of this study was to provide information in support of an investigation of thermal technologies as possible treatment process for buried wastes at the INEL. Material and energy balances and a cost estimate were generated for a representative plasma torch-based thermal waste treatment system operating in a pyrolysis mode. Two waste streams were selected which are representative of INEL buried wastes, large in volume, and difficult to treat by other technologies. These streams were a solidified nitrate sludge waste stream and a waste/soil mix of other buried waste components. The treatment scheme selected includes a main plasma chamber operating under pyrolyzing conditions; a plasma afterburner to provide additional residence time at high temperature to ensure complete destruction of hazardous organics; an off-gas treatment system; and a incinerator and stack to oxidize carbon monoxide to carbon dioxide and vent the clean, oxidized gases to atmosphere. The material balances generated provide materials flow and equipment duty information of sufficient accuracy to generate initial rough-order-of-magnitude (ROM) system capital and operating cost estimates for a representative plasma thermal processing system

  15. Incineration/vitrification of radioactive wastes and combustion of pyrolysis gases in thermal plasmas

    International Nuclear Information System (INIS)

    Girold, Ch.

    1997-03-01

    Two thermal plasma processes used for incineration of radioactive technological wastes (cellulose, plastics, rubber...) have been investigated. First, the different types of radioactive wastes are presented, with a special attention to those which may benefit from a high temperature thermal treatment. The most significant thermal plasma processes, suitable for this goal, are described. Then, the author deals with the post-combustion, in an oxygen plasma jet reactor, of gases from burnable radioactive waste pyrolysis. An experimental planning method as been used to evaluate the combustion performances in the reactor, with a wide range of gas composition and running parameters such as oxygen excess and electrical power. The results of a modeling of kinetics, based on 116 chemicals reactions between 25 species, are compared with experimental values. Finally, an oxygen plasma reactor where the arc is transferred on a basalt melt is experimented. The efficiency of the combustion and the homogeneity of the glass are discussed. The volatility of some glass elements and tracers added to the wastes is also approached in two different ways: by post-trial material balance and by an optical emission spectroscopic method. The author built a diagnostic method that allows the following versus time of the metallic vapours above the melt. (author)

  16. Chlorobenzene degeradation by non-thermal plasma combined with EG-TiO2/ZnO as a photocatalyst: Effect of photocatalyst on CO2 selectivity and byproducts reduction.

    Science.gov (United States)

    Ghorbani Shahna, Farshid; Bahrami, Abdulrahman; Alimohammadi, Iraj; Yarahmadi, Rassuol; Jaleh, Babak; Gandomi, Mastaneh; Ebrahimi, Hossein; Ad-Din Abedi, Kamal

    2017-02-15

    The non-thermal plasma (NTP) technique, which suffers from low selectivity in complete oxidation of volatile organic compounds to CO 2 and H 2 O, creates unwanted and harmful byproducts. NTP in concert with photocatalyst can resolve this limitation due to additional oxidation. TiO 2 and ZnO nanoparticles were coated on the surface of the expanded graphite and placed downstream of the NTP reactor under UV light. In this study, to compare the performance of NTP and the combined system, chlorobenzene removal, selectivity of CO 2 and byproducts formation were investigated. The results showed that the combined system enhanced both the removal efficiency and CO 2 selectivity. The output gas of the NTP reactor contained chlorobenzene, phosgene, O 3 , NO, NO 2 , CO, CO 2 , HCL and CL. The bulk of these byproducts was oxidized on the surface of the nanocomposite; as a result, the content of the byproducts in the output gas of the combined system decreased dramatically. The removal efficiency and CO 2 selectivity increased by rising the applied voltage and residence time because the collision between active species and pollutant molecules increases. Based on these results, the combined system is preferred due to a higher performance and lower formation of harmful byproducts. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Covariant kinetic dispersion theory of linear transverse waves parallel propagating in magnetized plasmas with thermal anisotropy

    International Nuclear Information System (INIS)

    Lazar, M.; Schlickeiser, R.

    2006-01-01

    The properties of transverse waves parallel propagating in magnetized plasmas with arbitrary composition and thermally anisotropic, are investigated on the basis of relativistic Vlasov-Maxwell equations. The transverse dispersion relations for plasmas with arbitrary distribution functions are derived. These dispersion relations describe the linear response of the system to the initial perturbations and thus define all existing linear (transverse) plasma modes in the system. By analytic continuation the dispersion relations in the whole complex frequency plane are constructed. Further analysis is restricted to the important case of anisotropic bi-Maxwellian equilibrium plasma distribution functions. Explicit forms of the relativistically correct transverse dispersion relations are derived that hold for any values of the plasma temperatures and the temperature anisotropy. In the limit of nonrelativistic plasma temperatures the dispersion relations are expressed in terms of plasma dispersion function, however, the dependence on frequency and wave numbers is markedly different from the standard noncovariant nonrelativistic analysis. Only in the strictly unphysical formal limit of an infinitely large speed of light, c→∞, does the nonrelativistic dispersion relations reduce to the standard noncovariant dispersion relations

  18. Near-surface thermal characterization of plasma facing components using the 3-omega method

    International Nuclear Information System (INIS)

    Dechaumphai, Edward; Barton, Joseph L.; Tesmer, Joseph R.; Moon, Jaeyun; Wang, Yongqiang; Tynan, George R.; Doerner, Russell P.; Chen, Renkun

    2014-01-01

    Near-surface regime plays an important role in thermal management of plasma facing components in fusion reactors. Here, we applied a technique referred to as the ‘3ω’ method to measure the thermal conductivity of near-surface regimes damaged by ion irradiation. By modulating the frequency of the heating current in a micro-fabricated heater strip, the technique enables the probing of near-surface thermal properties. The technique was applied to measure the thermal conductivity of a thin ion-irradiated layer on a tungsten substrate, which was found to decrease by nearly 60% relative to pristine tungsten for a Cu ion dosage of 0.2 dpa

  19. Kinetic study on non-thermal volumetric plasma decay in the early afterglow of air discharge generated by a short pulse microwave or laser

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wei, E-mail: yangwei861212@126.com; Zhou, Qianhong; Dong, Zhiwei [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)

    2016-08-28

    This paper reports a kinetic study on non-thermal plasma decay in the early afterglow of air discharge generated by short pulse microwave or laser. A global self-consistent model is based on the particle balance of complex plasma chemistry, electron energy equation, and gas thermal balance equation. Electron-ion Coulomb collision is included in the steady state Boltzmann equation solver to accurately describe the electron mobility and other transport coefficients. The model is used to simulate the afterglow of microsecond to nanosecond pulse microwave discharge in N{sub 2}, O{sub 2}, and air, as well as femtosecond laser filament discharge in dry and humid air. The simulated results for electron density decay are in quantitative agreement with the available measured ones. The evolution of plasma decay under an external electric field is also investigated, and the effect of gas heating is considered. The underlying mechanism of plasma density decay is unveiled through the above kinetic modeling.

  20. Propagation of thermal and hydromagnetic waves in an ionizing-recombining hydrogen plasma

    International Nuclear Information System (INIS)

    Di Sigalotti, Leonardo G.; Sira, Eloy; Rendon, Otto; Tremola, Ciro; Mendoza-Briceno, Cesar A.

    2004-01-01

    The propagation of thermal and magnetohydrodynamic (MHD) waves in a heat-conducting, hydrogen plasma, threaded by an external uniform magnetic field (B) and in which photoionization and photorecombination [H + +e - H+hν(χ)] processes are progressing, is investigated here using linear analysis. The resulting dispersion equation is solved analytically for varied strength (β<<1 and ∼1) and orientation of the magnetic field, where β denotes the ratio of plasma to magnetic pressures. Application of this model to the interstellar medium shows that heat conduction governs the propagation of thermal waves only at relatively high frequencies regardless of the plasma temperature, strength, and orientation of the magnetic field. When the direction of wave propagation is held perpendicular to B (i.e., k perpendicular B), the magnetosonic phase velocity is closely Alfvenic for β<<1, while for β∼1 both the hydrostatic and magnetic pressures determine the wave velocity. As long as k parallel B, the fast (transverse) magnetosonic wave becomes an Alfven wave for all frequencies independent of the plasma temperature and field strength, while the slow (longitudinal) magnetosonic wave becomes a pure sound wave. Amplification of thermal and MHD waves always occur at low frequencies and preferentially at temperatures for which the plasma is either weakly or partially ionized. Compared to previous analysis for the same hydrogen plasma model with B=0, the presence of the magnetic field makes the functional dependence of the physical quantities span a longer range of frequencies, which becomes progressively longer as the field strength is increased

  1. Plasma and neutralization effects: summary

    International Nuclear Information System (INIS)

    Tidman, D.A.

    1978-01-01

    The plasma working group considered the question of whether an intense heavy ion beam could be transported and accurately focussed across a target chamber radius of approximately 10 m on to a pellet of radius approximately 0.1 cm at the center of the chamber (a typical beam was taken as 3 kA, 40 GeV uranium injected into the reactor vessel with initial beam radius approximately 10 cm). Here we give a brief summary of our considerations. The conclusions were that focussing through relatively dense reactor chamber gases appears to be possible. Instabilities, if they arise, are expected only within the last few 10's of cm from the pellet, by which time they are unlikely to significantly degrade the beam focussing

  2. Thermal fluctuation levels of magnetic and electric fields in unmagnetized plasma: The rigorous relativistic kinetic theory

    International Nuclear Information System (INIS)

    Yoon, P. H.; Schlickeiser, R.; Kolberg, U.

    2014-01-01

    Any fully ionized collisionless plasma with finite random particle velocities contains electric and magnetic field fluctuations. The fluctuations can be of three different types: weakly damped, weakly propagating, or aperiodic. The kinetics of these fluctuations in general unmagnetized plasmas, governed by the competition of spontaneous emission, absorption, and stimulated emission processes, is investigated, extending the well-known results for weakly damped fluctuations. The generalized Kirchhoff radiation law for both collective and noncollective fluctuations is derived, which in stationary plasmas provides the equilibrium energy densities of electromagnetic fluctuations by the ratio of the respective spontaneous emission coefficient and the true absorption coefficient. As an illustrative example, the equilibrium energy densities of aperiodic transverse collective electric and magnetic fluctuations in an isotropic thermal electron-proton plasmas of density n e are calculated as |δB|=√((δB) 2 )=2.8(n e m e c 2 ) 1/2 g 1/2 β e 7/4 and |δE|=√((δE) 2 )=3.2(n e m e c 2 ) 1/2 g 1/3 β e 2 , where g and β e denote the plasma parameter and the thermal electron velocity in units of the speed of light, respectively. For densities and temperatures of the reionized early intergalactic medium, |δB|=6·10 −18 G and |δE|=2·10 −16 G result

  3. Application of the thermal plasma technique in the treatment of stone surfaces; Aplicacion de la tecnica de plasmas termicos en el tratamiento de superficies petreas

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez A, Z I

    2000-07-01

    The stone materials which form part of the cultural heritage of Mexico, are degraded under the united action of water, atmospheric gases, air pollution, temperature changes and the microorganisms action; provoking on the stone: fissures, crevices, scalings, fragmentations, pulverizations, etc. Therefore, the purpose of this work is to study the possibilities to apply a protective coating on the stone surfaces, previously clean and consolidated, through the thermal plasma technique. The purpose is to analyse the physical and chemical properties of three types of stone materials: quarry, tezontle and chiluca, usually used in constructions of cultural interest such as: historical monuments, churches, sculptures, etc., before and after to be submitted to the action of thermal plasma in order to examine the feasibility in the use of this coating technique in this type of applications. The application of conventional techniques to determine: porosity, density, absorption, low pressure water absorption and crystallization by total immersion of nuclear techniques such as: neutron activation analysis, x-ray diffraction and scanning electron microscopy as well as of instrumental techniques: optical microscopy, mechanical assays of compression, flexure and surface area calculations, allowed to know the chemical and physical properties of the stone material before and after to be treated through the thermal plasma technique, projecting quartz on the stones surface at different distances and current intensity and showing the effect caused by the modifications or surface alterations present by cause of the application of that coating. the obtained results provide a general panorama of the application of this technique as an alternative to the maintenance of the architectural inheritance built in stone. (Author)

  4. Thermal limiting effects in optical plasmonic waveguides

    International Nuclear Information System (INIS)

    Ershov, A.E.; Gerasimov, V.S.; Gavrilyuk, A.P.; Karpov, S.V.; Zakomirnyi, V.I.; Rasskazov, I.L.; Polyutov, S.P.

    2017-01-01

    We have studied thermal effects occurring during excitation of optical plasmonic waveguide (OPW) in the form of linear chain of spherical Ag nanoparticles by pulsed laser radiation. It was shown that heating and subsequent melting of the first irradiated particle in a chain can significantly deteriorate the transmission efficiency of OPW that is the crucial and limiting factor and continuous operation of OPW requires cooling devices. This effect is caused by suppression of particle's surface plasmon resonance due to reaching the melting point temperature. We have determined optimal excitation parameters which do not significantly affect the transmission efficiency of OPW. - Highlights: • The thermodynamic model was developed to study thermal effects at nanoscale. • Developed model considers temperature-dependent permittivity of the nanoparticles. • Thermal effects significantly suppress transmission efficiency of plasmonic chains. • Optimal parameters for stable operation of plasmonic chains were defined.

  5. Surface modification of gutta-percha cones by non-thermal plasma

    International Nuclear Information System (INIS)

    Prado, Maíra; Menezes, Marilia Santana de Oliveira; Gomes, Brenda Paula Figueiredo de Almeida; Barbosa, Carlos Augusto de Melo; Athias, Leonardo; Simão, Renata Antoun

    2016-01-01

    This study was designed to evaluate the effects of Oxygen and Argon plasma on gutta-percha surfaces. A total of 185 flat smooth gutta-percha surfaces were used. Samples were divided into groups: control: no plasma treatment; Oxygen: treatment with Oxygen plasma for 1 min; Argon: treatment with Argon plasma for 1 min. Samples were evaluated topographically by scanning electron microscopy and atomic force microscopy; and chemically by Fourier Transform-infrared Spectroscopy. A goniometer was used to determine the surface free energy and the wettability of the endodontic sealers. Additionally 60 bovine teeth were filled using pellets of gutta-percha (control, oxygen and argon plasma) and the sealers. Teeth were evaluated by push-out and microleakage tests. Data were statistically analyzed using specific tests. Argon plasma did not change the surface topography, while Oxygen plasma led to changes. Both treatments chemically modified the gutta-percha surface. Argon and Oxygen plasma increased the surface free energy and favored the wettability of AH Plus and Pulp Canal Sealer EWT. Regarding bond strength analysis, for AH Plus sealer, both plasma treatments on gutta-percha favored the bond strength to dentin. However, for Pulp Canal Sealer, there is no statistically significant influence. For leakage test, dye penetration occurred between sealer and dentin in all groups. In conclusion, Oxygen plasma led to both topographic and chemical changes in the gutta-percha surface, while Argon plasma caused only chemical changes. Both treatments increased the surface free energy, favoring the wettability of AH Plus and Pulp Canal Sealer EWT sealers and influenced positively in the adhesion and leakage. - Highlights: • Argon plasma did not change the gutta-percha surface. • Oxygen plasma led to topographic changes. • Both treatments chemically modified the gutta-percha surface. • Treatments increased the surface free energy and favored the wettability of sealers. • Plasma

  6. Surface modification of gutta-percha cones by non-thermal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Prado, Maíra, E-mail: maira@metalmat.ufrj.br [Department of Metallurgic and Materials Engineering, Federal University of Rio de Janeiro – UFRJ, Rio de Janeiro, RJ (Brazil); Menezes, Marilia Santana de Oliveira [Department of Metallurgic and Materials Engineering, Federal University of Rio de Janeiro – UFRJ, Rio de Janeiro, RJ (Brazil); Gomes, Brenda Paula Figueiredo de Almeida [Department of Restorative Dentistry, Endodontics Division, Piracicaba Dental School, State University of Campinas - UNICAMP, Piracicaba, SP (Brazil); Barbosa, Carlos Augusto de Melo [Department of Clinical Dentistry, Endodontic Division, Federal University of Rio de Janeiro – UFRJ, Rio de Janeiro, RJ (Brazil); Athias, Leonardo [Social Indicators Division, Brazilian Institute of Geography and Statistics, Rio de Janeiro, RJ (Brazil); Simão, Renata Antoun [Department of Metallurgic and Materials Engineering, Federal University of Rio de Janeiro – UFRJ, Rio de Janeiro, RJ (Brazil)

    2016-11-01

    This study was designed to evaluate the effects of Oxygen and Argon plasma on gutta-percha surfaces. A total of 185 flat smooth gutta-percha surfaces were used. Samples were divided into groups: control: no plasma treatment; Oxygen: treatment with Oxygen plasma for 1 min; Argon: treatment with Argon plasma for 1 min. Samples were evaluated topographically by scanning electron microscopy and atomic force microscopy; and chemically by Fourier Transform-infrared Spectroscopy. A goniometer was used to determine the surface free energy and the wettability of the endodontic sealers. Additionally 60 bovine teeth were filled using pellets of gutta-percha (control, oxygen and argon plasma) and the sealers. Teeth were evaluated by push-out and microleakage tests. Data were statistically analyzed using specific tests. Argon plasma did not change the surface topography, while Oxygen plasma led to changes. Both treatments chemically modified the gutta-percha surface. Argon and Oxygen plasma increased the surface free energy and favored the wettability of AH Plus and Pulp Canal Sealer EWT. Regarding bond strength analysis, for AH Plus sealer, both plasma treatments on gutta-percha favored the bond strength to dentin. However, for Pulp Canal Sealer, there is no statistically significant influence. For leakage test, dye penetration occurred between sealer and dentin in all groups. In conclusion, Oxygen plasma led to both topographic and chemical changes in the gutta-percha surface, while Argon plasma caused only chemical changes. Both treatments increased the surface free energy, favoring the wettability of AH Plus and Pulp Canal Sealer EWT sealers and influenced positively in the adhesion and leakage. - Highlights: • Argon plasma did not change the gutta-percha surface. • Oxygen plasma led to topographic changes. • Both treatments chemically modified the gutta-percha surface. • Treatments increased the surface free energy and favored the wettability of sealers. • Plasma

  7. The thermalization of soft modes in non-expanding isotropic quark gluon plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Blaizot, Jean-Paul, E-mail: jean-paul.blaizot@cea.fr [Institut de Physique Théorique, CNRS/UMR 3681, CEA Saclay, F-91191 Gif-sur-Yvette (France); Liao, Jinfeng [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); Mehtar-Tani, Yacine [Institute for Nuclear Theory, University of Washington, Seattle, WA 98195-1550 (United States)

    2017-05-15

    We discuss the role of elastic and inelastic collisions and their interplay in the thermalization of the quark–gluon plasma. We consider a simplified situation of a static plasma, spatially uniform and isotropic in momentum space. We focus on the small momentum region, which equilibrates first, and on a short time scale. We obtain a simple kinetic equation that allows for an analytic description of the most important regimes. The present analysis suggests that the formation of a Bose condensate, expected when only elastic collisions are present, is strongly hindered by the inelastic, radiative, processes.

  8. IAEA consultants' meeting on thermal response of plasma facing materials and components

    International Nuclear Information System (INIS)

    Janev, R.K.

    1990-07-01

    The present Summary Report contains brief proceedings and the main conclusions and recommendations of the IAEA Consultants' Meeting on ''Thermal Response of Plasma Facing Materials and Components'', which was organized by the IAEA Atomic and Molecular Data Unit and held on June 11-13, 1990, in Vienna, Austria. The Report also includes a categorization and assessment of currently studied plasma facing materials, a classification scheme of material properties data, required in fusion reactor design, and a survey of the urgently needed material properties data. (author)

  9. A Method to Construct Plasma with Nonlinear Density Enhancement Effect in Multiple Internal Inductively Coupled Plasmas

    International Nuclear Information System (INIS)

    Chen Zhipeng; Li Hong; Liu Qiuyan; Luo Chen; Xie Jinlin; Liu Wandong

    2011-01-01

    A method is proposed to built up plasma based on a nonlinear enhancement phenomenon of plasma density with discharge by multiple internal antennas simultaneously. It turns out that the plasma density under multiple sources is higher than the linear summation of the density under each source. This effect is helpful to reduce the fast exponential decay of plasma density in single internal inductively coupled plasma source and generating a larger-area plasma with multiple internal inductively coupled plasma sources. After a careful study on the balance between the enhancement and the decay of plasma density in experiments, a plasma is built up by four sources, which proves the feasibility of this method. According to the method, more sources and more intensive enhancement effect can be employed to further build up a high-density, large-area plasma for different applications. (low temperature plasma)

  10. Remelting of metallurgical fines using thermal plasma; Refusao de finos metalurgicos via plasma termico

    Energy Technology Data Exchange (ETDEWEB)

    Vicente, L C; Neto F, J B.F.; Bender, O W; Collares, M P

    1993-12-31

    A plasma furnace was developed for remelting of ferro alloys and silicon fines. The furnace capacity was about 4 Kg of silicon and power about 50 kW. The fine (20 to 100 mesh) was fed into the furnace directly at the high temperature zone. This system was tested for remelting silicon fines and the results in the recovery of silicon was about 95% and it took place a refine of aluminium and calcium. (author) 10 refs., 4 figs., 2 tabs.

  11. Fundamental limitations of non-thermal plasma processing for internal combustion engine NOx control

    International Nuclear Information System (INIS)

    Penetrante, B.M.

    1993-01-01

    This paper discusses the physics and chemistry of non-thermal plasma processing for post-combustion NO x control in internal combustion engines. A comparison of electron beam and electrical discharge processing is made regarding their power consumption, radical production, NO x removal mechanisms, and by product formation. Can non-thermal deNO x operate efficiently without additives or catalysts? How much electrical power does it cost to operate? What are the by-products of the process? This paper addresses these fundamental issues based on an analysis of the electron-molecule processes and chemical kinetics

  12. Effects of thermal pollution on marine life

    International Nuclear Information System (INIS)

    Peres, J.M.

    1976-01-01

    After a short review of the conditions and importance of the releases of heated water from fossil- or nuclear- fueled power plants, the two-fold consequences of thermal pollution are stated: consequences from the transit damaging, by thermal stress and/or mechanical effects, planctonic organisms attracted in the stream, and consequences from heating of the receiving environment. Other related effect on marine populations should not be neglected: effects of antifouling (chlorine mostly) and anticorrosion products; synergic action of raised temperature and chemical pollutants. In the present state of knowledge, the hazards of thermal pollution in the marine environment should not be overestimated so far as effluent dilution and diffusion are sufficient, which implies that the site be selected in an area where coastal circulation is strong enough and the disposal procedures be improved [fr

  13. Effects of magnetic fields on the quark–gluon plasma

    Energy Technology Data Exchange (ETDEWEB)

    Bali, G.S. [Institute for Theoretical Physics, Universität Regensburg, D-93040 Regensburg (Germany); Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Bruckmann, F. [Institute for Theoretical Physics, Universität Regensburg, D-93040 Regensburg (Germany); Endrődi, G., E-mail: gergely.endrodi@physik.uni-r.de [Institute for Theoretical Physics, Universität Regensburg, D-93040 Regensburg (Germany); Fodor, Z. [Eötvös University, Theoretical Physics, Pázmány P. s 1/A, H-1117, Budapest (Hungary); Bergische Universität Wuppertal, Theoretical Physics, 42119 Wuppertal (Germany); Jülich Supercomputing Centre, Forschungszentrum Jülich, D-52425 Jülich (Germany); Katz, S.D. [Eötvös University, Theoretical Physics, Pázmány P. s 1/A, H-1117, Budapest (Hungary); MTA-ELTE Lendület Lattice Gauge Theory Research Group (Hungary); Schäfer, A. [Institute for Theoretical Physics, Universität Regensburg, D-93040 Regensburg (Germany)

    2014-11-15

    In this talk, the response of the thermal QCD medium to external (electro)magnetic fields is studied using continuum extrapolated lattice results at physical quark masses. The magnetic susceptibility of QCD is calculated, revealing a strong paramagnetic response at high temperatures. This paramagnetism is shown to result in an anisotropic squeezing of the quark–gluon plasma in non-central heavy-ion collisions, implying a sizeable contribution to the elliptic flow. Another aspect is the magnetic response of topologically non-trivial domains to the magnetic field. We quantify this effect on the lattice and compare the results to a simple model estimate.

  14. Thermal responses of tokamak reactor first walls during cyclic plasma burns

    International Nuclear Information System (INIS)

    Smith, D.L.; Charak, I.

    1978-01-01

    The CINDA-3G computer code has been adapted to analyze the thermal responses and operating limitations of two fusion reactor first-wall concepts under normal cyclic operation. A component of an LMFBR computer code has been modified and adapted to analyze the ablative behavior of first-walls after a plasma disruption. The first-wall design concepts considered are a forced-circulation water-cooled stainless steel panel with and without a monolithic graphite liner. The thermal gradients in the metal wall and liner have been determined for several burn-cycle scenarios and the extent of surface ablation that results from a plasma disruption has been determined for stainless steel and graphite first surfaces

  15. Production of coloured glass-ceramics from incinerator ash using thermal plasma technology.

    Science.gov (United States)

    Cheng, T W; Huang, M Z; Tzeng, C C; Cheng, K B; Ueng, T H

    2007-08-01

    Incineration is a major treatment process for municipal solid waste in Taiwan. It is estimated that over 1.5 Mt of incinerator ash are produced annually. This study proposes using thermal plasma technology to treat incinerator ash. Sintered glass-ceramics were produced using quenched vitrified slag with colouring agents added. The experimental results showed that the major crystalline phases developed in the sintered glass-ceramics were gehlenite and wollastonite, but many other secondary phases also appeared depending on the colouring agents added. The physical/mechanical properties, chemical resistance and toxicity characteristic leaching procedure of the coloured glass-ceramics were satisfactory. The glass-ceramic products obtained from incinerator ash treated with thermal plasma technology have great potential for building applications.

  16. Thermal responses of tokamak reactor first walls during cyclic plasma burns

    International Nuclear Information System (INIS)

    Smith, D.L.; Charak, I.

    1977-01-01

    The CINDA-3G computer code has been adapted to analyze the thermal responses and operating limitations of two fusion reactor first-wall concepts under normal cyclic operation. A component of an LMFBR computer has been modified and adapted to analyze the ablative behavior of first-walls after a plasma disruption. The first-wall design concepts considered are a forced-circulation water-cooled stainless steel panel with and without a monolithic graphite liner. The thermal gradients in the metal wall and liner have been determined for several burn-cycle scenarios and the extent of surface ablation that results from a plasma disruption has been determined for stainless steel and graphite first surfaces

  17. Thermal loads on tokamak plasma-facing components during normal operation and disruptions

    International Nuclear Information System (INIS)

    McGrath, R.T.

    1990-01-01

    Power loadings experienced by tokamak plasma-facing components during normal operation and during off-normal events are discussed. A model for power and particle flow in the tokamak boundary layer is presented and model predictions are compared to infrared measurements of component heating. The inclusion of the full three-dimensional geometry of the components and of the magnetic flux surface is very important in the modeling. Experimental measurements show that misalignment of component armour tile surfaces by only a millimeter can lead to significant localized heating. An application to the design of plasma-facing components for future machines is presented. Finally, thermal loads expected during tokamak disruptions are discussed. The primary problems are surface melting and vaporization due to localized intense heating during the disruption thermal quench and volumetric heating of the component armour and structure due to localised impact of runaway electrons. (author)

  18. Interaction of heavy ion beams with a hydrogen plasma: plasma lens effect and stopping power enhancement

    International Nuclear Information System (INIS)

    Gardes, D.; Bimbot, R.; Della-Negra, S.; Dumail, M.; Kubica, B.; Richard, A.; Rivet, M.F.; Servajean, A.; Deutsch, C.; Maynard, G.

    1988-01-01

    By coupling a hydrogen plasma to a Tandem accelerator, transmission and energy losses of 2 MeV/u carbon and sulfur beams passing through a plasma target have been investigated. Fluctuations in beam transmission have been observed and attributed to a plasma lens effect. Moreover, energy loss measurements indicate an enhanced stopping power of the plasma relative to its cold matter equivalent

  19. A novel approach to the pacemaker infection with non-thermal atmospheric pressure plasma

    Science.gov (United States)

    Zhang, Yuchen; Li, Yu; Li, Yinglong; Yu, Shuang; Li, Haiyan; Zhang, Jue

    2017-08-01

    Although the pacemaker (PM) is a key cardiac implantable electrical device for life-threatening arrhythmias treatment, the related infection is a challenge. Thus, the aim of this study is to validate cold plasma as a potential technology for the disinfection of infected pacemakers. Fifty donated PMs were cleaned and sterilized before use and then infected with Staphylococcus aureus ( S. aureus). Then, each experimental group was treated with cold plasma treatment for 1 min, 3 min, 5 min and 7 min, while the control group was immersed with sterilized water. Effectiveness of disinfection was evaluated by using CFU counting method and confocal laser scanning microscopy (CLSM). The physicochemical properties of water treated with cold plasma at different time were evaluated, including water temperature change and oxidation reduction potential (ORP). The major reactive species generated by the cold plasma equipment during cold plasma were analyzed with optical emission spectroscopy (OES). No live bacteria were detected with CFU counting method after 7 min of cold plasma treatment, which matches with the CLSM results. The ORP value of water and H2O2 concentration changed significantly after treating with cold plasma. Furthermore, reactive oxygen species (ROS) and reactive nitrogen species (RNS), especially NO, O (777 nm) and O (844 nm) were probably key inactivation agents in cold plasma treatment. These results indicate that cold plasma could be an effective technology for the disinfection of implantable devices.

  20. Influence of ECR-RF plasma modification on surface and thermal properties of polyester copolymer

    Directory of Open Access Journals (Sweden)

    Fray Miroslawa El

    2015-12-01

    Full Text Available In this paper we report a study on influence of radio-frequency (RF plasma induced with electron cyclotron resonance (ECR on multiblock copolymer containing butylene terephthalate hard segments (PBT and butylene dilinoleate (BDLA soft segments. The changes in thermal properties were studied by DSC. The changes in wettability of PBT-BDLA surfaces were studied by water contact angle (WCA. We found that ECR-RF plasma surface treatment for 60 s led to decrease of WCA, while prolonged exposure of plasma led to increase of WCA after N2 and N2O2 treatment up to 70°–80°. The O2 reduced the WCA to 50°–56°. IR measurements confirmed that the N2O2 plasma led to formation of polar groups. SEM investigations showed that plasma treatment led to minor surfaces changes. Collectively, plasma treatment, especially O2, induced surface hydrophilicity what could be beneficial for increased cell adhesion in future biomedical applications of these materials.

  1. Analysis of the step responses of laminar premixed flames to forcing by non-thermal plasma

    KAUST Repository

    Lacoste, Deanna A.

    2016-07-16

    The step responses of lean methane-air flames to non-thermal plasma forcing is reported. The experimental setup consists of an axisymmetric burner, with a nozzle made of a quartz tube. The equivalence ratio is 0.95, allowing stabilization of the flame in a V-shape or an M-shape geometry, over a central stainless steel rod. The plasma is produced by short pulses of 10-ns duration, 8-kV maximum voltage amplitude, applied at 10 kHz. The central rod is used as a cathode, while the anode is a stainless steel ring, fixed on the outer surface of the quartz tube. Plasma forcing is produced by positive or negative steps of plasma. The step response of the flame is investigated through heat release rate (HRR) fluctuations, to facilitate comparisons with flame response to acoustic perturbations. The chemiluminescence of CH* between two consecutive pulses was recorded using an intensified camera equipped with an optical filter to estimate the HRR fluctuations. First, the results show that the flame does not respond to each single plasma pulse, but is affected only by the average plasma power, confirming the step nature of the forcing. The temporal evolutions of HRR are analyzed and the flame transfer functions are determined. A forcing mechanism, as a local increase in the reactivity of the fluid close to the rod, is proposed and compared with numerical simulations. Experiments and numerical simulations are in good qualitative agreement. © 2016.

  2. Thermalization of the quark-gluon plasma and dynamical formation of Bose-Einstein Condensate

    OpenAIRE

    Liao, Jinfeng

    2012-01-01

    We report recent progress on understanding the thermalization of the quark-gluon plasma during the early stage in a heavy ion collision. The initially high overpopulation in the pre-equilibrium gluonic matter (``glasma'') is shown to play a crucial role. The strongly interacting nature (and thus fast evolution) naturally arises as an {\\em emergent property} of this pre-equilibrium matter where the intrinsic coupling is weak but the highly occupied gluon states coherently amplify the scatterin...

  3. Application of Structure-Based Models of Mechanical and Thermal Properties on Plasma Sprayed Coatings

    Czech Academy of Sciences Publication Activity Database

    Vilémová, Monika; Matějíček, Jiří; Mušálek, Radek; Nohava, J.

    2012-01-01

    Roč. 21, 3-4 (2012), s. 372-382 ISSN 1059-9630 R&D Projects: GA MŠk ME 901 Institutional research plan: CEZ:AV0Z20430508 Keywords : analytical model * elastic modulus * finite element modeling * image analysis * modeling of properties * thermal conductivity * water stabilized plasma Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 1.481, year: 2012 http://www.springerlink.com/content/3m24812367315142/fulltext. pdf

  4. Chemically different non-thermal plasmas target distinct cell death pathways

    Czech Academy of Sciences Publication Activity Database

    Lunov, Oleg; Zablotskyy, Vitaliy A.; Churpita, Olexandr; Lunova, M.; Jirsa, M.; Dejneka, Alexandr; Kubinová, Šárka

    2017-01-01

    Roč. 7, č. 1 (2017), s. 1-17, č. článku 600. ISSN 2045-2322 Grant - others:AV ČR(CZ) Fellowship J. E. Purkyně Institutional support: RVO:68378271 Keywords : chemically different * non-thermal plasmas * target distinct cell death pathways Subject RIV: BO - Biophysics OBOR OECD: Biophysics Impact factor: 4.259, year: 2016

  5. Cell death induced by ozone and various non-thermal plasmas: therapeutic perspectives and limitations

    Czech Academy of Sciences Publication Activity Database

    Lunov, Oleg; Zablotskyy, Vitaliy A.; Churpita, Olexandr; Chánová, Eliška; Syková, Eva; Dejneka, Alexandr; Kubinová, Šárka

    2014-01-01

    Roč. 4, NOV (2014), "7129-1"-"7129-11" ISSN 2045-2322 R&D Projects: GA MŠk LO1309 Grant - others:AV ČR(CZ) M100101219 Institutional support: RVO:68378271 ; RVO:61389013 ; RVO:68378041 Keywords : cell death * non-thermal plasma * therapeutic perspectives Subject RIV: BO - Biophysics; FH - Neurology (UEM-P); CD - Macromolecular Chemistry (UMCH-V) Impact factor: 5.578, year: 2014

  6. Chiral magnetic effect in the anisotropic quark-gluon plasma

    International Nuclear Information System (INIS)

    Ali-Akbari, Mohammad; Taghavi, Seyed Farid

    2015-01-01

    An anisotropic thermal plasma phase of a strongly coupled gauge theory can be holographically modelled by an anisotropic AdS black hole. The temperature and anisotropy parameter of the AdS black hole background of interest http://dx.doi.org/10.1007/JHEP07(2011)054 is specified by the location of the horizon and the value of the Dilaton field at the horizon. Interestingly, for the first time, we obtain two functions for the values of the horizon and Dilaton field in terms of the temperature and anisotropy parameter. Then by introducing a number of spinning probe D7-branes in the anisotropic background, we compute the value of the chiral magnetic effect (CME). We observe that in the isotropic and anisotropic plasma the value of the CME is equal for the massless quarks. However, at fixed temperature, raising the anisotropy in the system will increase the value of the CME for the massive quarks.

  7. Synthesis of ZnO nanopowders by DC thermal plasma for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Soo-Jung; Choi, Jinsub [Department of Chemical Engineering, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon 402-751 (Korea, Republic of); Park, Dong-Wha, E-mail: dwpark@inha.ac.kr [Department of Chemical Engineering, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon 402-751 (Korea, Republic of)

    2013-05-01

    Highlights: ► ZnO nanopowders were synthesized using DC thermal plasma process. ► Type and flow rate of reaction gas were controlled as experimental variables. ► Various morphologies were identified by changing the reaction gas. ► The photovoltaic performances were promoted by removing the unreacted precursors. ► DSSCs based on 1D nanostructure ZnO show the enhanced energy conversion efficiency. -- Abstract: Zinc oxide (ZnO) nanopowders were synthesized from commercially available micro-sized zinc powders (Aldrich Co., 98%, 10 μm) by a DC thermal plasma process at atmospheric pressure. The micro-sized zinc powders were vaporized in the plasma region, after which the plasma processing equipment was rapidly quenched, resulting in the formation of ZnO nanopowders with a size of less than 300 nm. Two different reaction gases of oxygen and carbon dioxide were used as the oxygen source and each gas flow rate was controlled as a process variable. The obtained ZnO nanopowders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). All synthesized ZnO nanopowders showed high crystalline wurtzite structures and the differences in their morphologies were strongly dependent on the operating variables. The photocurrent–voltage (J–V) curve of the ZnO nanopowders with a dye of ruthenium (II) 535 bis-TBA (N719, Solaronix) in redox electrolyte showed an overall energy conversion efficiency (η) of 2.54%, demonstrating that the application of the mass-producible ZnO nanopowders by thermal plasma processing to DSSC was feasible.

  8. Effects of Cold Plasma on Food Quality: A Review.

    Science.gov (United States)

    Pankaj, Shashi K; Wan, Zifan; Keener, Kevin M

    2018-01-01

    Cold plasma (CP) technology has proven very effective as an alternative tool for food decontamination and shelf-life extension. The impact of CP on food quality is very crucial for its acceptance as an alternative food processing technology. Due to the non-thermal nature, CP treatments have shown no or minimal impacts on the physical, chemical, nutritional and sensory attributes of various products. This review also discusses the negative impacts and limitations posed by CP technology for food products. The limited studies on interactions of CP species with food components at the molecular level offers future research opportunities. It also highlights the need for optimization studies to mitigate the negative impacts on visual, chemical, nutritional and functional properties of food products. The design versatility, non-thermal, economical and environmentally friendly nature of CP offers unique advantages over traditional processing technologies. However, CP processing is still in its nascent form and needs further research to reach its potential.

  9. Disinfection of Streptococcus mutans biofilm by a non-thermal atmospheric plasma brush

    Science.gov (United States)

    Hong, Qing; Dong, Xiaoqing; Chen, Meng; Xu, Yuanxi; Sun, Hongmin; Hong, Liang; Wang, Yong; Yu, Qingsong

    2016-07-01

    This study investigated the argon plasma treatment effect on disinfecting dental biofilm by using an atmospheric pressure plasma brush. Streptococcus mutans biofilms were developed for 3 days on the surfaces of hydroxyapatite (HA) discs, which were used to simulate human tooth enamel. After plasma treatment, cell viability in the S. mutans biofilms was characterized by using 3-(4,5-dimethylazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and confocal laser scanning microscopy (CLSM). Compared with the untreated control group, about 90% bacterial reduction in the biofilms was observed after 1 min plasma treatment. Scanning electron microscopy (SEM) examination indicated severe cell damages occurred on the top surface of the plasma treated biofilms. Confocal laser scanning microscopy (CLSM) showed that plasma treatment was effective as deep as 20 µm into the biofilms. When combined with antibiotic treatment using 0.2% chlorhexidine digluconate solution, the plasma treatment became more effective and over 96% bacterial reduction was observed with 1 min plasma treatment.

  10. SUPPRESSION OF PARALLEL TRANSPORT IN TURBULENT MAGNETIZED PLASMAS AND ITS IMPACT ON THE NON-THERMAL AND THERMAL ASPECTS OF SOLAR FLARES

    Energy Technology Data Exchange (ETDEWEB)

    Bian, Nicolas H.; Kontar, Eduard P. [School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Emslie, A. Gordon, E-mail: n.bian@physics.gla.ac.uk, E-mail: emslieg@wku.edu [Department of Physics and Astronomy, Western Kentucky University, Bowling Green, KY 42101 (United States)

    2016-06-20

    The transport of the energy contained in electrons, both thermal and suprathermal, in solar flares plays a key role in our understanding of many aspects of the flare phenomenon, from the spatial distribution of hard X-ray emission to global energetics. Motivated by recent RHESSI observations that point to the existence of a mechanism that confines electrons to the coronal parts of flare loops more effectively than Coulomb collisions, we here consider the impact of pitch-angle scattering off turbulent magnetic fluctuations on the parallel transport of electrons in flaring coronal loops. It is shown that the presence of such a scattering mechanism in addition to Coulomb collisional scattering can significantly reduce the parallel thermal and electrical conductivities relative to their collisional values. We provide illustrative expressions for the resulting thermoelectric coefficients that relate the thermal flux and electrical current density to the temperature gradient and the applied electric field. We then evaluate the effect of these modified transport coefficients on the flare coronal temperature that can be attained, on the post-impulsive-phase cooling of heated coronal plasma, and on the importance of the beam-neutralizing return current on both ambient heating and the energy loss rate of accelerated electrons. We also discuss the possible ways in which anomalous transport processes have an impact on the required overall energy associated with accelerated electrons in solar flares.

  11. The energy partitioning of non-thermal particles in a plasma: the Coulomb logarithm revisited

    International Nuclear Information System (INIS)

    Singleton, Robert L Jr; Brown, Lowell S

    2008-01-01

    The charged particle stopping power in a highly ionized and weakly to moderately coupled plasma has been calculated exactly to leading and next-to-leading accuracy in the plasma density by Brown, Preston and Singleton (BPS). Since the calculational techniques of BPS might be unfamiliar to some, and since the same methodology can also be used for other energy transport phenomena, we will review the main ideas behind the calculation. BPS used their stopping power calculation to derive a Fokker-Planck equation, also accurate to leading and next-to-leading orders, and we will also review this. We use this Fokker-Planck equation to compute the electron-ion energy partitioning of a charged particle traversing a plasma. The motivation for this application is ignition for inertial confinement fusion-more energy delivered to the ions means a better chance of ignition, and conversely. It is therefore important to calculate the fractional energy loss to electrons and ions as accurately as possible. One method by which one calculates the electron-ion energy splitting of a charged particle traversing a plasma involves integrating the stopping power dE/dx. However, as the charged particle slows down and becomes thermalized into the background plasma, this method of calculating the electron-ion energy splitting breaks down. As a result, it suffers a systematic error that may be as large as T/E 0 , where T is the plasma temperature and E 0 is the initial energy of the charged particle. The formalism presented here is designed to account for the thermalization process and it provides results that are near-exact.

  12. Thermal effects on parallel-propagating electron cyclotron waves

    International Nuclear Information System (INIS)

    Robinson, P.A.

    1987-01-01

    Thermal effects on the dispersion of right-handed electron cyclotron waves propagating parallel to a uniform, ambient magnetic field are investigated in the strictly non-relativistic ('classical') and weakly relativistic approximations for real frequency and complex wave vector. In each approximation, the two branches of the RH mode reconnect near the cyclotron frequency as the plasma temperature is increased or the density is lowered. This reconnection occurs in a manner different from that previously assumed at parallel propagation and from that at perpendicular propagation, giving rise to a new mode near the cold plasma cut-off frequency ωsub(xC). For both parallel and perpendicular propagation, it is noted that reconnection occurs approximately when the cyclotron linewidth equals the width of the stop-band in the cold plasma dispersion relation. Inclusion of weakly relativistic effects is found to be necessary for quantitative calculations and for an accurate treatment of the new mode near ωsub(xC). Weakly relativistic effects also modify the analytic properties of the dispersion relation so as to introduce a new family of weakly damped and undamped solutions. (author)

  13. Thermal-hydraulic and thermo-mechanical design of plasma facing components for SST-1 tokamak

    International Nuclear Information System (INIS)

    Chaudhuri, Paritosh; Santra, P.; Chenna Reddy, D.; Parashar, S.K.S.

    2014-01-01

    The Plasma Facing Components (PFCs) are one of the major sub-systems of ssT-1 tokamak. PFC of ssT-1 consisting of divertors, passive stabilizers, baffles and limiters are designed to be compatible for steady state operation. The main consideration in the design of the PFC cooling is the steady state heat removal of up to 1 MW/m 2 . The PFC has been designed to withstand the peak heat fluxes and also without significant erosion such that frequent replacement of the armor is not necessary. Design considerations included 2-D steady state and transient tile temperature distribution and resulting thermal loads in PFC during baking, and cooling, coolant parameters necessary to maintain optimum thermal-hydraulic design, and tile fitting mechanism. Finite Element (FE) models using ANSYS have been developed to carry out the heat transfer and stress analyses of the PFC to understand its thermal and mechanical behaviors. The results of the calculation led to a good understanding of the coolant flow behavior and the temperature distribution in the tube wall and the different parts of the PFC. Thermal analysis of the PFC is carried out with the purpose of evaluating the thermal mechanical behavior of PFCs. The detailed thermal-hydraulic and thermo-mechanical designs of PFCs of ssT-1 are discussed in this paper. (authors)

  14. Failure Analysis of Multilayered Suspension Plasma-Sprayed Thermal Barrier Coatings for Gas Turbine Applications

    Science.gov (United States)

    Gupta, M.; Markocsan, N.; Rocchio-Heller, R.; Liu, J.; Li, X.-H.; Östergren, L.

    2018-02-01

    Improvement in the performance of thermal barrier coatings (TBCs) is one of the key objectives for further development of gas turbine applications. The material most commonly used as TBC topcoat is yttria-stabilized zirconia (YSZ). However, the usage of YSZ is limited by the operating temperature range which in turn restricts the engine efficiency. Materials such as pyrochlores, perovskites, rare earth garnets are suitable candidates which could replace YSZ as they exhibit lower thermal conductivity and higher phase stability at elevated temperatures. The objective of this work was to investigate different multilayered TBCs consisting of advanced topcoat materials fabricated by suspension plasma spraying (SPS). The investigated topcoat materials were YSZ, dysprosia-stabilized zirconia, gadolinium zirconate, and ceria-yttria-stabilized zirconia. All topcoats were deposited by TriplexPro-210TM plasma spray gun and radial injection of suspension. Lifetime of these samples was examined by thermal cyclic fatigue and thermal shock testing. Microstructure analysis of as-sprayed and failed specimens was performed with scanning electron microscope. The failure mechanisms in each case have been discussed in this article. The results show that SPS could be a promising route to produce multilayered TBCs for high-temperature applications.

  15. Performance Testing of Suspension Plasma Sprayed Thermal Barrier Coatings Produced with Varied Suspension Parameters

    Directory of Open Access Journals (Sweden)

    Nicholas Curry

    2015-07-01

    Full Text Available Suspension plasma spraying has become an emerging technology for the production of thermal barrier coatings for the gas turbine industry. Presently, though commercial systems for coating production are available, coatings remain in the development stage. Suitable suspension parameters for coating production remain an outstanding question and the influence of suspension properties on the final coatings is not well known. For this study, a number of suspensions were produced with varied solid loadings, powder size distributions and solvents. Suspensions were sprayed onto superalloy substrates coated with high velocity air fuel (HVAF -sprayed bond coats. Plasma spray parameters were selected to generate columnar structures based on previous experiments and were maintained at constant to discover the influence of the suspension behavior on coating microstructures. Testing of the produced thermal barrier coating (TBC systems has included thermal cyclic fatigue testing and thermal conductivity analysis. Pore size distribution has been characterized by mercury infiltration porosimetry. Results show a strong influence of suspension viscosity and surface tension on the microstructure of the produced coatings.

  16. On the effect of electron's runaway in partially ionized hydrogen semiclassical nonideal plasma

    International Nuclear Information System (INIS)

    Turekhanova, K.M.

    2011-01-01

    Complete text of publication follows. The effect of runaway electrons occurs frequently in tokamak plasmas. The majority of experiments in tokamak research have been devoted to the study of confinement properties of runaway electrons. Runaway electrons are reason of various destroying untolarance in tokamak plasmas. At high plasma density, when the critical energy is comparable with the rest energy the multiplication of runaway electrons accelerate at the sacrifice of increase of plasma density. The plasma conductivity is determined by electrons with energy several times higher than the thermal one and does not practically depend on slower electrons distribution. It is important to analyze the probability of runaway electrons at investigation of physical properties of nonideal plasmas under external electric field and running numerical simulations of their. The present paper is devoted to the investigation of effect of runaway electrons in partially ionized hydrogen dense plasma using the effective potentials of particle's interaction. At the investigation of composition of plasma we used the Saha equation with corrections to nonideality (lowering of ionization potentials). The Saha equation was solved for obtaining of plasma ionization stages at the different number density and temperature. As well, when take into account quantum-mechanical diffraction and screening effects, whereas free path of electrons increases with increase of plasma coupling parameter. The condition for appearance of runaway electrons in semiclassical partially ionized plasma is more favorable in regime of dense plasma. In summary it means that the probability of runaway electron in dense plasma is more than the same in rarified plasma that is possibly connected with formation of some ordered structures in dense plasma.

  17. The subtle interplay of elastic and inelastic collisions in the thermalization of the quark–gluon plasma

    Energy Technology Data Exchange (ETDEWEB)

    Blaizot, Jean-Paul [Theoretical Physics, CEA, Saclay (France); Liao, Jinfeng [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); Mehtar-Tani, Yacine [Institute for Nuclear Theory, University of Washington, Seattle, WA 98195-1550 (United States)

    2016-12-15

    Using kinetic theory, we analyze the interplay of elastic and inelastic collisions in the thermalization of the quark-gluon plasma. The main focus is the dynamics and equilibration of long wavelength modes.

  18. Application of non-thermal plasma reactor and Fenton reaction for degradation of ibuprofen

    Energy Technology Data Exchange (ETDEWEB)

    Marković, Marijana [Center of Chemistry, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia); Jović, Milica; Stanković, Dalibor [Innovation Center, Faculty of Chemistry, University of Belgrade, P.O. Box 51, 11058 Belgrade 118 (Serbia); Kovačević, Vesna [Faculty of Physics, University of Belgrade, P.O. Box 44, 11000 Belgrade (Serbia); Roglić, Goran [Faculty of Chemistry, University of Belgrade, P.O. Box 51, 11058 Belgrade 118 (Serbia); Gojgić-Cvijović, Gordana [Center of Chemistry, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia); Manojlović, Dragan, E-mail: manojlo@chem.bg.ac.rs [Faculty of Chemistry, University of Belgrade, P.O. Box 51, 11058 Belgrade 118 (Serbia)

    2015-02-01

    Pharmaceutical compounds have been detected frequently in surface and ground water. Advanced Oxidation Processes (AOPs) were reported as very efficient for removal of various organic compounds. Nevertheless, due to incomplete degradation, toxic intermediates can induce more severe effects than the parent compound. Therefore, toxicity studies are necessary for the evaluation of possible uses of AOPs. In this study the effectiveness and capacity for environmental application of three different AOPs were estimated. They were applied and evaluated for removal of ibuprofen from water solutions. Therefore, two treatments were performed in a non-thermal plasma reactor with dielectric barrier discharge with and without a homogenous catalyst (Fe{sup 2+}). The third treatment was the Fenton reaction. The degradation rate of ibuprofen was measured by HPLC-DAD and the main degradation products were identified using LC–MS TOF. Twelve degradation products were identified, and there were differences according to the various treatments applied. Toxicity effects were determined with two bioassays: Vibrio fischeri and Artemia salina. The efficiency of AOPs was demonstrated for all treatments, where after 15 min degradation percentage was over 80% accompanied by opening of the aromatic ring. In the treatment with homogenous catalyst degradation reached 99%. V. fischeri toxicity test has shown greater sensitivity to ibuprofen solution after the Fenton treatment in comparison to A. salina. - Highlights: • Twelve ibuprofen degradation products were identified in total. • The degradation percentage differed between treatments (DBD/Fe{sup 2+} was 99%). • In DBD/Fe{sup 2+} only aliphatic degradation products were identified. • V. fischeri was sensitive to ibuprofen solution after the Fenton treatment. • A. salina showed no toxic effect when exposed to all post treatment solutions.

  19. Application of non-thermal plasma reactor and Fenton reaction for degradation of ibuprofen

    International Nuclear Information System (INIS)

    Marković, Marijana; Jović, Milica; Stanković, Dalibor; Kovačević, Vesna; Roglić, Goran; Gojgić-Cvijović, Gordana; Manojlović, Dragan

    2015-01-01

    Pharmaceutical compounds have been detected frequently in surface and ground water. Advanced Oxidation Processes (AOPs) were reported as very efficient for removal of various organic compounds. Nevertheless, due to incomplete degradation, toxic intermediates can induce more severe effects than the parent compound. Therefore, toxicity studies are necessary for the evaluation of possible uses of AOPs. In this study the effectiveness and capacity for environmental application of three different AOPs were estimated. They were applied and evaluated for removal of ibuprofen from water solutions. Therefore, two treatments were performed in a non-thermal plasma reactor with dielectric barrier discharge with and without a homogenous catalyst (Fe 2+ ). The third treatment was the Fenton reaction. The degradation rate of ibuprofen was measured by HPLC-DAD and the main degradation products were identified using LC–MS TOF. Twelve degradation products were identified, and there were differences according to the various treatments applied. Toxicity effects were determined with two bioassays: Vibrio fischeri and Artemia salina. The efficiency of AOPs was demonstrated for all treatments, where after 15 min degradation percentage was over 80% accompanied by opening of the aromatic ring. In the treatment with homogenous catalyst degradation reached 99%. V. fischeri toxicity test has shown greater sensitivity to ibuprofen solution after the Fenton treatment in comparison to A. salina. - Highlights: • Twelve ibuprofen degradation products were identified in total. • The degradation percentage differed between treatments (DBD/Fe 2+ was 99%). • In DBD/Fe 2+ only aliphatic degradation products were identified. • V. fischeri was sensitive to ibuprofen solution after the Fenton treatment. • A. salina showed no toxic effect when exposed to all post treatment solutions

  20. Thermal Bridge Effects in Window Grooves

    DEFF Research Database (Denmark)

    Rose, Jørgen

    1997-01-01

    In this report thermal bridge effects in window grooves are analyzed. The analysis is performed using different thicknesses of the window groove insulation, to evaluate what the optimal solution is.All analysis in the report is performed using both 2- and 3-dimensional numerical analysis....

  1. Thermal effects in concrete containment analysis

    International Nuclear Information System (INIS)

    Pfeiffer, P.A.; Kennedy, J.M.; Marchertas, A.H.

    1988-01-01

    Analyses of the thermo-mechanical response of the 1:6-scale reinforced concrete containment are presented. Three temperature- pressure scenarios are analyzed to complete loss of the pressure integrity. These results are compared to the analysis of pressure alone, to assess the importance of thermal effects. 19 refs., 9 figs., 8 tabs

  2. Thermal imaging of spin Peltier effect

    Science.gov (United States)

    Daimon, Shunsuke; Iguchi, Ryo; Hioki, Tomosato; Saitoh, Eiji; Uchida, Ken-Ichi

    2016-12-01

    The Peltier effect modulates the temperature of a junction comprising two different conductors in response to charge currents across the junction, which is used in solid-state heat pumps and temperature controllers in electronics. Recently, in spintronics, a spin counterpart of the Peltier effect was observed. The `spin Peltier effect' modulates the temperature of a magnetic junction in response to spin currents. Here we report thermal imaging of the spin Peltier effect; using active thermography technique, we visualize the temperature modulation induced by spin currents injected into a magnetic insulator from an adjacent metal. The thermal images reveal characteristic distribution of spin-current-induced heat sources, resulting in the temperature change confined only in the vicinity of the metal/insulator interface. This finding allows us to estimate the actual magnitude of the temperature modulation induced by the spin Peltier effect, which is more than one order of magnitude greater than previously believed.

  3. Application of a plasma-jet for skin antisepsis: analysis of the thermal action of the plasma by laser scanning microscopy

    International Nuclear Information System (INIS)

    Lademann, O; Kramer, A; Richter, H; Patzelt, A; Alborova, A; Humme, D; Weltmann, K-D; Hartmann, B; Hinz, P; Koch, S

    2010-01-01

    Recently, it was reported that a plasma-jet could be efficiently applied for the antisepsis of wounds. In this case, the discharge in an argon gas stream was used to produce a so-called ''cold plasma'' on the skin surface. The thermal action of the plasma on the skin was investigated in the present study by means of laser scanning microscopy (LSM) and by histological analysis. Consequently, the plasma beam was moved with a definite velocity at an optimal distance over the skin surface. The structural changes of the tissue were analyzed. It was found by LSM that a thermal damage could be detected only in the upper cell layers of the stratum corneum (SC) at moving velocities of the plasma beam, usually applied in clinical practice. Deeper parts of the SC were not damaged. The structural changes were so superficial that they could be detected only by LSM but not by analysis of the histological sections

  4. Effects of fueling profiles on plasma transport

    International Nuclear Information System (INIS)

    Mense, A.T.; Houlberg, W.A.; Attenberger, S.E.; Milora, S.L.

    1978-04-01

    A one-dimensional (1-D), multifluid transport model is used to investigate the effects of particle fueling profiles on plasma transport in an ignition-sized tokamak (TNS). Normal diffusive properties of plasmas will likely maintain the density at the center of the discharge even if no active fueling is provided there. This significantly relaxes the requirements for fuel penetration. Not only is lower fuel penetration easier to achieve, but it may have the advantage of reducing or eliminating density gradient-driven trapped particle microinstabilities. Simulation of discrete pellet fueling indicates that relatively low velocity (approximately 10 3 m/sec) pellets may be sufficient to fuel a TNS-sized device (approximately 1.25-m minor radius), to produce a relatively broad, cool edge region of plasma which should reduce the potential for sputtering, and also to reduce the likelihood of trapped particle mode dominated transport. Low penetrating pellets containing up to 10 to 20 percent of the total plasma ions can produce fluctuations in density and temperature at the plasma edge, but the pressure profile and fusion alpha production remain almost constant

  5. Investigation of Dusts Effect and Negative Ion in DC Plasmas by Electric Probes

    Science.gov (United States)

    Oh, Hye Taek; Kang, Inje; Bae, Min-Keun; Park, Insun; Lee, Seunghwa; Jeong, Seojin; Chung, Kyu-Sun

    2017-10-01

    Dust is typically negatively charged by electron attachment whose thermal velocities are fast compared to that of the heavier ions. The negatively charged particles can play a role of negative ions which affect the quasi-neutrality of background plasma. To investigate effect of metal dusts and negative ion on plasma and materials, metal dusts are injected into background Ar plasma which is generated by tungsten filament using dust dispenser on Cubical Plasma Device (CPD). The CPD has following conditions: size =24x24x24cm3, plasma source =DC filament plasma (ne 1x10x1010, Te 2eV), background gas =Ar, dusts =tungsten powder (diameter 1.89micron). The dust dispenser is developed to quantitate of metal dust by ultrasonic transducer. Electronegative plasmas are generated by adding O2 + Ar plasma to compare negative ion and dust effect. A few grams of micron-sized dusts are placed in the dust dispenser which is located at the upper side of the Cubical Plasma Device. The falling particles by dust dispenser are mainly charged up by the collection of the background plasma. The change in parameters due to negative ion production are characterized by measuring the floating and plasma potential, electron temperature and negative ion density using electric probes.

  6. Separation method in the problem of a beam-plasma interaction in bounded warm plasma under the effect of HF electric field

    International Nuclear Information System (INIS)

    EI-Shorbagy, Kh.H.

    2002-11-01

    The stabilization effect of a strong HP electric field on beam-plasma instability in a cylindrical warm plasma waveguide is discussed. A new mathematical technique 'separation method' which has been applied to the two-fluid plasma model to separate the equations, which describe the system, into two parts, temporal and space parts. Plasma electrons are considered to have a thermal velocity. It is shown that a HF electric field has no essential influence on dispersion characteristics of unstable surface waves excited in a warm plasma waveguide by a low-density electron beam. The region of instability only slightly narrowing and the growth rate decreases by a small parameter and this result has been reduced compared to cold plasma. Also, it is found that the plasma electrons have not affected the solution of the space part of the problem. (author)

  7. Is fat perception a thermal effect?

    Science.gov (United States)

    Prinz, J F; de Wijk, R A; Huntjens, L A H; Engelen, L; Polet, I A

    2007-04-01

    It has been generally assumed that fat is detected by its flavour and by its lubrication of the oral mucosa. A recent study reported a correlation of -.99 between perceived temperature of a product and its fat content. This was significantly higher than correlations of sensory scores for fat flavour, mouthfeel, and afterfeel. This suggested a third detection mechanism; fat may be detected via its effect on the thermal conductivity of the food. In 3 studies, thermal sensitivity in humans was investigated to verify whether oral thermal receptors are sufficiently rapid and accurate to play a role in the perception of fats. The thermal sensitivity of the lips and oral mucosa of the anterior and middle one-third of the tongue were assessed using a Peltier device. Subjects detected 0.5 Hz fluctuations in temperature of 0.08'C on the lower lip, 0.26 degrees C and 1.36 degrees C at the tip and dorsum of the tongue, demonstrating that the lips are sufficiently sensitive to detect small differences in temperature. In two further experiments subjects ingested custards and mayonnaises and then spat out samples after 5, 10, or 20 sec. The temperature of the food and oral mucosa was measured before and after spitting and the rates of heating were calculated. Results suggest assessment of thermal conductivity of food may be used to assess fat content.

  8. Thermal Plasma Spheroidization of High-Nitrogen Stainless Steel Powder Alloys Synthesized by Mechanical Alloying

    Science.gov (United States)

    Razumov, Nikolay G.; Popovich, Anatoly A.; Wang, QingSheng

    2018-03-01

    This paper presents the results of experimental studies on the treatment of Fe-23Cr-11Mn-1N high-nitrogen stainless steel powder alloys, synthesized by the mechanical alloying (MA) of elemental powders in the flow of a thermal plasma. Fe-23Cr-11Mn-1N high-nitrogen stainless steel powder alloys were prepared by MA in the attritor under an argon atmosphere. For spheroidization of Fe-23Cr-11Mn-1N high-nitrogen stainless steel powder alloys, the TekSphero 15 plant manufactured by Tekna Plasma Systems Inc was used. The studies have shown the possibility of obtaining Fe-23Cr-11Mn-1N high-nitrogen spherical powders steel alloys from the powder obtained by MA. According to the results of a series of experiments, it was found that the results of plasma spheroidization of powders essentially depend on the size of the fraction due to some difference in the particle shape and flowability, and on the gas regime of the plasma torch. It is established that during the plasma spheroidization process, some of the nitrogen leaves the alloy. The loss rate of nitrogen depends on the size of the initial particles.

  9. Design and optimization of coating structure for the thermal barrier coatings fabricated by atmospheric plasma spraying via finite element method

    Directory of Open Access Journals (Sweden)

    L. Wang

    2014-06-01

    Full Text Available The first prerequisite for fabricating the thermal barrier coatings (TBCs with excellent performance is to find an optimized coating structure with high thermal insulation effect and low residual stress. This paper discusses the design and optimization of a suitable coating structure for the TBCs prepared by atmospheric plasma spraying (APS using the finite element method. The design and optimization processes comply with the rules step by step, as the structure develops from a simple to a complex one. The research results indicate that the suitable thicknesses of the bond-coating and top-coating are 60–120 μm and 300–420 μm, respectively, for the single ceramic layer YSZ/NiCoCrAlY APS-TBC. The embedded interlayer (50 wt.%YSZ + 50 wt.%NiCoCrAlY will further reduce the residual stress without sacrificing the thermal insulation effect. The double ceramic layer was further considered which was based on the single ceramic layer TBC. The embedded interlayer and the upper additional ceramic layer will have a best match between the low residual stress and high thermal insulation effect. Finally, the optimized coating structure was obtained, i.e., the La2Ce2O7(LC/YSZ/Interlayer/NiCoCrAlY coating structure with appropriate layer thickness is the best choice. The effective thermal conductivity of this optimized LC/YSZ/IL/BL TBC is 13.2% lower than that of the typical single ceramic layer YSZ/BL TBC.

  10. Optimizing Compliance and Thermal Conductivity of Plasma Sprayed Thermal Barrier Coatings via Controlled Powders and Processing Strategies

    Science.gov (United States)

    Tan, Yang; Srinivasan, Vasudevan; Nakamura, Toshio; Sampath, Sanjay; Bertrand, Pierre; Bertrand, Ghislaine

    2012-09-01

    The properties and performance of plasma-sprayed thermal barrier coatings (TBCs) are strongly dependent on the microstructural defects, which are affected by starting powder morphology and processing conditions. Of particular interest is the use of hollow powders which not only allow for efficient melting of zirconia ceramics but also produce lower conductivity and more compliant coatings. Typical industrial hollow spray powders have an assortment of densities resulting in masking potential advantages of the hollow morphology. In this study, we have conducted process mapping strategies using a novel uniform shell thickness hollow powder to control the defect microstructure and properties. Correlations among coating properties, microstructure, and processing reveal feasibility to produce highly compliant and low conductivity TBC through a combination of optimized feedstock and processing conditions. The results are presented through the framework of process maps establishing correlations among process, microstructure, and properties and providing opportunities for optimization of TBCs.

  11. Transition phenomena and thermal transport properties in LHD plasmas with an electron internal transport barrier

    International Nuclear Information System (INIS)

    Shimozuma, T.; Kubo, S.; Idei, H.; Inagaki, S.; Tamura, N.; Tokuzawa, T.; Morisaki, T.; Watanabe, K.Y.; Ida, K.; Yamada, I.; Narihara, K.; Muto, S.; Yokoyama, M.; Yoshimura, Y.; Notake, T.; Ohkubo, K.; Seki, T.; Saito, K.; Kumazawa, R.; Mutoh, T.; Watari, T.; Komori, A.

    2005-01-01

    Two types of improved core confinement were observed during centrally focused electron cyclotron heating (ECH) into plasmas sustained by counter (CNTR) and Co neutral beam injections (NBI) in the Large Helical Device. The CNTR NBI plasma displayed transition phenomena to the high-electron-temperature state and had a clear electron internal transport barrier, while the Co NBI plasma did not show a clear transition or an ECH power threshold but showed broad high temperature profiles with moderate temperature gradient. This indicated that the Co NBI plasma with additional ECH also had an improved core confinement. The electron heat transport characteristics of these plasmas were directly investigated using heat pulse propagation excited by modulated ECH. These effects appear to be related to the m/n = 2/1 rational surface or the island induced by NBI beam-driven current

  12. Magnetic properties of nanocrystalline CoFe{sub 2}O{sub 4} synthesized by thermal plasma in large scale

    Energy Technology Data Exchange (ETDEWEB)

    Nawale, A.B.; Kanhe, N.S. [Department of Physics, University of Pune, Pune 411007 (India); Patil, K.R. [Center for Materials Characterizations, National Chemical Laboratory, Dr. Hommi Bhabha Road, Pashan, Pune 411008 (India); Reddy, V.R.; Gupta, A. [UGC-DAE Consortium for Scientific Research, Indore Centre, University Campus, Khandwa Road, Indore 452 017 (India); Kale, B.B. [Center for Materials for Electronics Technology, Department of Information Technology, Government of India, Panchawati, Off Pashan Road, Pune 411008 (India); Bhoraskar, S.V. [Department of Physics, University of Pune, Pune 411007 (India); Mathe, V.L., E-mail: vlmathe@physics.unipune.ac.in [Department of Physics, University of Pune, Pune 411007 (India); Das, A.K. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2012-12-14

    The paper reports the large scale synthesis of nanoparticles of CoFe{sub 2}O{sub 4} using thermal plasma reactor by gas phase condensation method. The yield of formation was found to be around 15 g h{sup -1}. The magnetic properties of CoFe{sub 2}O{sub 4}, synthesized at different reactor powers, were investigated in view of studying the effect of operating parameters of plasma reactor on the structural reorganization leading to the different cation distribution. The values of saturation magnetization, coercivity and remanent magnetization were found to be influenced by input power in thermal plasma. Although the increase in saturation magnetization was marginal (61 emu g{sup -1} to 70 emu g{sup -1}) with increasing plasma power; a significant increase in the coercivity (552 Oe to 849 Oe) and remanent magnetization (16 emu g{sup -1} to 26 emu g{sup -1}) were also noticed. The Moessbauer spectra showed mixed spinel structure and canted spin order for the as synthesized nanoparticles. The detailed analysis of cation distribution using the Moessbauer spectroscopy and X-ray photoelectron spectroscopy leads to the conclusion that the sample synthesized at an optimized power shows the different site selective states. -- Highlights: Black-Right-Pointing-Pointer A rapid synthesis method for synthesizing magnetic nanoparticles of cobalt ferrite. Black-Right-Pointing-Pointer The average particle size ranges between 25 and 40 nm; as revealed by the FESEM analysis. Black-Right-Pointing-Pointer Magnetic properties are influenced by different operating parameters.

  13. Thermal resistance matrix representation of thermal effects and thermal design in multi-finger power heterojunction bipolar transistors

    Institute of Scientific and Technical Information of China (English)

    Jin Dong-Yue; Zhang Wan-Rong; Chen Liang; Fu Qiang; Xiao Ying; Wang Ren-Qing; Zhao Xin

    2011-01-01

    The thermal resistance matrix including self-heating thermal resistance and thermal coupling resistance is presented to describe the thermal effects of multi-finger power heterojunction bipolar transistors. The dependence of thermal resistance matrix on finger spacing is also investigated. It is shown that both self-heating thermal resistance and thermal coupling resistance are lowered by increasing the finger spacing, in which the downward dissipated heat path is widened and the heat flow from adjacent fingers is effectively suppressed. The decrease of self-heating thermal resistance and thermal coupling resistance is helpful for improving the thermal stability of power devices. Furthermore, with the aid of the thermal resistance matrix, a 10-finger power heterojunction bipolar transistor (HBT) with non-uniform finger spacing is designed for high thermal stability. The optimized structure can effectively lower the peak temperature while maintaining a uniformity of the temperature profile at various biases and thus the device effectively may operate at a higher power level.

  14. Environmental effects of thermal power plants

    International Nuclear Information System (INIS)

    Gerlitzky, M.; Friedrich, R.; Unger, H.

    1986-02-01

    Reviewing critically the present literature, the effects of thermal power plants on the environment are studied. At first, the loads of the different power plant types are compiled. With regard to the effects of emission reduction proceedings the pollutant emissions are quantified. The second chapter shows the effects on the ecological factors, which could be caused by the most important emission components of thermal power plants. Where it is possible, relations between immissions respectively depositions and their effects on climate, man, flora, fauna and materials will be given. This shows that many effects depend strongly on the local landscape, climate and use of natural resources. Therefore, it appears efficient to ascertain different load limits. The last chapter gives a suggestion for an ecological compatibility test (ECT) of thermal power plants. In modular form the ECT deals with the emission fields, waste heat, pollution burden of air and water, noise, loss of area and aesthetical aspects. Limits depending on local conditions and use of area will be discussed. (orig.) [de

  15. Mueller matrix polarimetry on plasma sprayed thermal barrier coatings for porosity measurement.

    Science.gov (United States)

    Luo, David A; Barraza, Enrique T; Kudenov, Michael W

    2017-12-10

    Yttria-stabilized zirconia (YSZ) is the most widely used material for thermal plasma sprayed thermal barrier coatings (TBCs) used to protect gas turbine engine parts in demanding operation environments. The superior material properties of YSZ coatings are related to their internal porosity level. By quantifying the porosity level, tighter control on the spraying process can be achieved to produce reliable coatings. Currently, destructive measurement methods are widely used to measure the porosity level. In this paper, we describe a novel nondestructive approach that is applicable to classify the porosity level of plasma sprayed YSZ TBCs via Mueller matrix polarimetry. A rotating retarder Mueller matrix polarimeter was used to measure the polarization properties of the plasma sprayed YSZ coatings with different porosity levels. From these measurements, it was determined that a sample's measured depolarization ratio is dependent on the sample's surface roughness and porosity level. To this end, we correlate the depolarization ratio with the samples' surface roughness, as measured by a contact profilometer, as well as the total porosity level, in percentage measured using a micrograph and stereological analysis. With the use of this technique, a full-field and rapid measurement of porosity level can be achieved.

  16. Toluene degradation by non-thermal plasma combined with a ferroelectric catalyst.

    Science.gov (United States)

    Liang, Wen-Jun; Ma, Lin; Liu, Huan; Li, Jian

    2013-08-01

    Degradation of toluene in a gas by non-thermal plasma with a ferroelectric catalyst was studied at normal temperature and atmospheric pressure. Spontaneous polarization material (BaTiO3) and photocatalyst (TiO2) were added into plasma system simultively. Toluene degradation efficiency and specific energy density during the discharge process were investigated. Furthermore, byproducts and degradation mechanisms of toluene were also investigated. The toluene degradation efficiency increased when non-thermal plasma technology was combined with the catalyst. The toluene degradation efficiencies of the different catalysts tested were in the following order: BaTiO3/TiO2>BaTiO3>TiO2>no catalyst. A mass ratio of 2.38:1 was optimum for the BaTiO3 and TiO2 catalyst. The outlet gas was analyzed by gas chromatography and Fourier transform infrared spectroscopy, and the main compounds detected were CO2, H2O, O3 and benzene ring derivatives. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Preparation of boron-rich aluminum boride nanoparticles by RF thermal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sooseok [Inha University, Department of Chemical Engineering and Regional Innovation Center for Environmental Technology of Thermal Plasma (Korea, Republic of); Matsuo, Jiro; Cheng, Yingying [Tokyo Institute of Technology, Department of Environmental Chemistry and Engineering (Japan); Watanabe, Takayuki, E-mail: watanabe@chemenv.titech.ac.jp [Kyushu University, Department of Chemical Engineering (Japan)

    2013-08-15

    Boron-rich compounds of AlB{sub 12} and AlB{sub 10} nanoparticles were synthesized by a radiofrequency thermal plasma. Aluminum and boron raw powders were evaporated in virtue of high enthalpy of the thermal plasma in upstream region, followed by the formation of aluminum boride nanoparticles in the tail region of plasma flame with rapid quenching. A high production rate of aluminum boride was confirmed by the X-ray diffraction measurement in the case of high input power, high boron content in raw material and helium inner gas. Polyhedral nanoparticles of 20.8 nm in mean size were observed by a transmission electron microscope. In the raw powder mixture of aluminum, titanium, and boron, titanium-boride nanoparticles were synthesized preferentially, because the Gibbs free energy for the boridation of titanium is lower than that of aluminum. Since the nucleation temperature of boron is higher than that of aluminum, the condensation of metal monomers onto boron nuclei results in the formation of boron-rich aluminum boride nanoparticles.

  18. Net emission coefficient for CO–H2 thermal plasmas with the consideration of molecular systems

    International Nuclear Information System (INIS)

    Billoux, T.; Cressault, Y.; Gleizes, A.

    2015-01-01

    This paper deals with the calculation of net emission coefficients (NECs) for CO–H 2 thermal plasmas. This task required the elaboration of a complete spectroscopic database including atoms and molecules formed by carbon, oxygen and hydrogen elements. We have used a systematic line by line method to calculate all the main radiative contributions which are the atomic and molecular continua, the atomic lines and the molecular (diatomic and polyatomic) lines. The main diatomic electronic systems for CO–H 2 plasmas and the triatomic molecular bands were considered. We present some variations of the net emission coefficient versus temperature, for various pressures and for two relative proportions of the components. The role of the diatomic molecules is important at temperatures lower than 5000 K whereas the net emission coefficient presents an unusual peak at temperature around 1000 K, due to the presence of the CO 2 molecule presenting a strong infrared radiation. Finally, the results show that the NEC slightly depends on the relative proportion of CO and H 2 . - highlights: • We calculate radiative losses from CO–H 2 thermal plasmas. • We use the up-to-date atomic and molecular databases. • The influence of CO 2 molecule is very important at low temperature. • The relative maximum of the net emission coefficient at low temperature is unusual

  19. Transport of thermal plasma above the auroral ionosphere in the presence of electrostatic ion-cyclotron turbulence

    Directory of Open Access Journals (Sweden)

    V. E. Zakharov

    Full Text Available The electron component of intensive electric currents flowing along the geomagnetic field lines excites turbulence in the thermal magnetospheric plasma. The protons are then scattered by the excited electromagnetic waves, and as a result the plasma is stable. As the electron and ion temperatures of the background plasma are approximately equal each other, here electrostatic ion-cyclotron (EIC turbulence is considered. In the nonisothermal plasma the ion-acoustic turbulence may occur additionally. The anomalous resistivity of the plasma causes large-scale differences of the electrostatic potential along the magnetic field lines. The presence of these differences provides heating and acceleration of the thermal and energetic auroral plasma. The investigation of the energy and momentum balance of the plasma and waves in the turbulent region is performed numerically, taking the magnetospheric convection and thermal conductivity of the plasma into account. As shown for the quasi-steady state, EIC turbulence may provide differences of the electric potential of ΔV≈1–10 kV at altitudes of 500 < h < 10 000 km above the Earth's surface. In the turbulent region, the temperatures of the electrons and protons increase only a few times in comparison with the background values.

    Key words. Magnetospheric physics (electric fields; plasma waves and instabilities

     

  20. Influence of coil current modulation on polycrystalline diamond film deposition by irradiation of Ar/CH4/H2 inductively coupled thermal plasmas

    Science.gov (United States)

    Betsuin, Toshiki; Tanaka, Yasunori; Arai, T.; Uesugi, Y.; Ishijima, T.

    2018-03-01

    This paper describes the application of an Ar/CH4/H2 inductively coupled thermal plasma with and without coil current modulation to synthesise diamond films. Induction thermal plasma with coil current modulation is referred to as modulated induction thermal plasma (M-ITP), while that without modulation is referred to as non-modulated ITP (NM-ITP). First, spectroscopic observations of NM-ITP and M-ITP with different modulation waveforms were made to estimate the composition in flux from the thermal plasma by measuring the time evolution in the spectral intensity from the species. Secondly, we studied polycrystalline diamond film deposition tests on a Si substrate, and we studied monocrystalline diamond film growth tests using the irradiation of NM-ITP and M-ITP. From these tests, diamond nucleation effects by M-ITP were found. Finally, following the irradiation results, we attempted to use a time-series irradiation of M-ITP and NM-ITP for polycrystalline diamond film deposition on a Si substrate. The results indicated that numerous larger diamond particles were deposited with a high population density on the Si substrate by time-series irradiation.

  1. Study on the effects of physical plasma on in-vitro cultivates cells

    International Nuclear Information System (INIS)

    Strassenburg, Susanne

    2014-03-01

    This study focused on the interactions of non thermal atmospheric pressure plasma on in vitro cultured keratinocytes (HaCaT keratinocytes) and melanoma cells (MV3). Three different plasma sources were used: a plasma jet (kINPen 09), a surface DBD (dielectric barrier discharge) and a volume DBD. For analyzing basic effects of plasma on cells, influence of physical plasma on viability, on DNA and on induction of ROS were investigated. Following assays were used: -- Viability: - neutral red uptake assay, cell counting (number of viable cells, cell integrity) - BrdU assay (proliferation) - Annexin V and propidium iodide staining, flow cytometry (induction of apoptosis), -- DNA: - alkaline comet assay (detection of DNA damage) - staining of DNA with propidium iodide, flow cytometry (cell cycle analysis), -- ROS: - H2DCFDA assay, flow cytometry (detection of ROS-positive cells). In addition to the effects which where induced by the plasma sources, the influence of the plasma treatment regime (direct, indirect and direct with medium exchange), the working gas (argon, air) and the surrounding liquids (cell culture medium: RPMI, IMDM; buffer solutions: HBSS, PBS) on the extent of the plasma cell effects were investigated. All plasma sources induced treatment time-dependent effects in HaCaT keratinocytes and melanoma cells (MV3): - loss of viable cells and reduced proliferation - induction of apoptosis after the longest treatment times - DNA damage 1 h after plasma treatment, 24 h after plasma treatment DNA damage was present only after the longest treatment times, evidence for DNA damage repair - due to accumulation of cells in G2/M phase, cell count in G1 phase (24 h) is lower - increase of ROS-positive cells 1 h and 24 h after plasma treatment. It was shown that cells which were cultured in RPMI showed stronger effects (stronger loss of viability and more DNA damage) than cells which were cultured in IMDM. Also plasma-treated buffer solutions (HBSS, PBS) induced DNA

  2. Effective thermal conductivity of nanofluids: the effects of microstructure

    International Nuclear Information System (INIS)

    Fan Jing; Wang Liqiu

    2010-01-01

    We examine numerically the effects of particle-fluid thermal conductivity ratio, particle volume fraction, particle size distribution and particle aggregation on macroscale thermal properties for seven kinds of two-dimensional nanofluids. The results show that the radius of gyration and the non-dimensional particle-fluid interfacial area are two important parameters in characterizing the geometrical structure of nanoparticles. A non-uniform particle size is found to be unfavourable for the conductivity enhancement, while particle-aggregation benefits the enhancement especially when the radius of gyration of aggregates is large. Without considering the interfacial thermal resistance, a larger non-dimensional particle-fluid interfacial area between the base fluid and the nanoparticles is also desirable for enhancing thermal conductivity. The nanofluids with nanoparticles of connected cross-shape show a much higher (lower) effective thermal conductivity when the particle-fluid conductivity ratio is larger (smaller) than 1.

  3. Changing the surface properties on naval steel as result of non-thermal plasma treatment

    Science.gov (United States)

    Hnatiuc, B.; Sabău, A.; Dumitrache, C. L.; Hnatiuc, M.; Crețu, M.; Astanei, D.

    2016-08-01

    The problem of corrosion, related to Biofouling formation, is an issue with very high importance in the maritime domain. According to new rules, the paints and all the technologies for the conditioning of naval materials must fulfil more restrictive environmental conditions. In order to solve this issue, different new clean technologies have been proposed. Among them, the use of non-thermal plasmas produced at atmospheric pressure plays a very important role. This study concerns the opportunity of plasma treatment for preparation or conditioning of naval steel OL36 type. The plasma reactors chosen for the experiments can operate at atmospheric pressure and are easy to use in industrial conditions. They are based on electrical discharges GlidArc and Spark, which already proved their efficiency for the surface activation or even for coatings of the surface. The non-thermal character of the plasma is ensured by a gas flow blown through the electrical discharges. One power supply has been used for reactors that provide a 5 kV voltage and a maximum current of 100 mA. The modifications of the surface properties and composition have been studied by XPS technique (X-ray Photoelectron Spectroscopy). There were taken into consideration 5 samples: 4 of them undergoing a Mini-torch plasma, a Gliding Spark, a GlidArc with dry air and a GlidArc with CO2, respectively the fifth sample which is the untreated witness. Before the plasma treatment, samples of naval steel were processed in order to obtain mechanical gloss. The time of treatment was chosen to 12 minutes. In the spectroscopic analysis, done on a ULVAC-PHI, Inc. PHI 5000 Versa Probe scanning XPS microprobe, a monocromated Al Kα X-ray source with a spot size of 100 μm2 was used to scan each sample while the photoelectrons were collected at a 45-degree take-off angle. Differences were found between atomic concentrations in each individual case, which proves that the active species produced by each type of plasma affects

  4. Effects of Warmness and Spatial Nonuniformity of the Plasma Waveguide on Periodic Absolute Parametric Instability

    International Nuclear Information System (INIS)

    Zaki, N.G.; Bekheit, A.H.

    2011-01-01

    The periodic absolute parametric instability (API) of the low-frequency oscillations excited by a monochromatic pumping field of arbitrary amplitude in a warm I-D nonuniform magneto active plasma is investigated. One can use the separation method to solve the two-fluid plasma equations which describe the system. The method used enables us to determine the frequencies and growth rates of unstable modes and the self-consistent electric field. Plasma electrons are considered to have a thermal velocity. One can examine different solutions for the spatial equation in the following cases: A) API in uniform Plasma B) API in nonuniform plasma, we study this case for two variants: B.1) Exact harmonic oscillator and B.2) Bounded harmonic oscillator (bounded plasma). Increment is found in the buildup of the oscillations, and it is shown that the spatial nonuniformity of the plasma exerts a stabilizing effect on the parametric instability. It is shown that the growth rate of API in warm plasma is reduced compared to cold plasma. It is found also that the warmness of the plasma has no effect on the solution of the space part of the problem ( only through the separation constant )

  5. Effects of warmness and spatial nonuniformity of plasma waveguide on periodic absolute parametric instability

    International Nuclear Information System (INIS)

    Zaki, N.G.; Bekheit, A.H.

    2011-01-01

    The periodic absolute parametric instability (API) of the low-frequency oscillations excited by a monochromatic pumping field of an arbitrary amplitude in a warm 1-D (one-dimensional) nonuniform magnetoactive plasma is investigated. The separation method can be used for solving the two-fluid plasma equations describing the system. By applying this method we were able to determine the frequencies and growth rates of unstable modes and the self-consistent electric field. Plasma electrons are considered to have a thermal velocity. Different solutions for the spatial equation can be obtained the following cases: A) API in a uniform plasma, B) API in a nonuniform plasma. The latter has been studied here for two cases: B.1) the exact harmonic oscillator and B.2) the bounded harmonic oscillator (a bounded plasma). An increment has been found in the build-up of the oscillations, and it has been shown that the spatial nonuniformity of the plasma exerts the stabilizing effect on the parametric instability. A reduced growth rate of API in the warm plasma, in comparison to the cold plasma, is reported. It has also been found that the warmness of the plasma has no effect on the solution of the space part of the problem (only through the separation constant). (authors)

  6. A numerical model of non-equilibrium thermal plasmas. I. Transport properties

    Science.gov (United States)

    Zhang, Xiao-Ning; Li, He-Ping; Murphy, Anthony B.; Xia, Wei-Dong

    2013-03-01

    A self-consistent and complete numerical model for investigating the fundamental processes in a non-equilibrium thermal plasma system consists of the governing equations and the corresponding physical properties of the plasmas. In this paper, a new kinetic theory of the transport properties of two-temperature (2-T) plasmas, based on the solution of the Boltzmann equation using a modified Chapman-Enskog method, is presented. This work is motivated by the large discrepancies between the theories for the calculation of the transport properties of 2-T plasmas proposed by different authors in previous publications. In the present paper, the coupling between electrons and heavy species is taken into account, but reasonable simplifications are adopted, based on the physical fact that me/mh ≪ 1, where me and mh are, respectively, the masses of electrons and heavy species. A new set of formulas for the transport coefficients of 2-T plasmas is obtained. The new theory has important physical and practical advantages over previous approaches. In particular, the diffusion coefficients are complete and satisfy the mass conversation law due to the consideration of the coupling between electrons and heavy species. Moreover, this essential requirement is satisfied without increasing the complexity of the transport coefficient formulas. Expressions for the 2-T combined diffusion coefficients are obtained. The expressions for the transport coefficients can be reduced to the corresponding well-established expressions for plasmas in local thermodynamic equilibrium for the case in which the electron and heavy-species temperatures are equal.

  7. Interaction of supra-thermal ions with turbulence in a magnetized toroidal plasma

    International Nuclear Information System (INIS)

    Plyushchev, G.

    2009-01-01

    This thesis addresses the interaction of a supra-thermal ion beam with turbulence in the simple magnetized toroidal plasma of TORPEX. The first part of the Thesis deals with the ohmic assisted discharges on TORPEX. The aim of these discharges is the investigation of the open to closed magnetic field line transition. The relevant magnetic diagnostics were developed. Ohmic assisted discharges with a maximum plasma current up to 1 kA are routinely obtained. The equilibrium conditions on the vacuum magnetic field configuration were investigated. In the second part of the Thesis, the design of the fast ion source and detector are discussed. The accelerating electric field needed for the fast ion source was optimized. The fast ion source was constructed and commissioned. To detect the fast ions a specially designed gridded energy analyzer was used. The electron energy distribution function was obtained to demonstrate the efficiency of the detector. The experiments with the fast ion beam were conducted in different plasma regions of TORPEX. In the third part of the Thesis, numerical simulations are used to interpret the measured fast ion beam behavior. It is shown that a simple single particle equation of motion explains the beam behavior in the experiments in the absence of plasma. To explain the fast ion beam experiments with the plasma a turbulent electric field must be used. The model that takes into account this turbulent electrical field qualitatively explains the shape of the fast ion current density profile in the different plasma regions of TORPEX. The vertically elongated fast ion current density profiles are explained by a spread in the fast ion velocity distribution. The theoretically predicted radial fast ion beam spreading due to the turbulent electric field was observed in the experiment. (author)

  8. A numerical model of non-equilibrium thermal plasmas. I. Transport properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhang XiaoNing; Xia WeiDong [Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei, Anhui Province 230026 (China); Li HePing [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Murphy, Anthony B. [CSIRO Materials Science and Engineering, PO Box 218, Lindfield NSW 2070 (Australia)

    2013-03-15

    A self-consistent and complete numerical model for investigating the fundamental processes in a non-equilibrium thermal plasma system consists of the governing equations and the corresponding physical properties of the plasmas. In this paper, a new kinetic theory of the transport properties of two-temperature (2-T) plasmas, based on the solution of the Boltzmann equation using a modified Chapman-Enskog method, is presented. This work is motivated by the large discrepancies between the theories for the calculation of the transport properties of 2-T plasmas proposed by different authors in previous publications. In the present paper, the coupling between electrons and heavy species is taken into account, but reasonable simplifications are adopted, based on the physical fact that m{sub e}/m{sub h} Much-Less-Than 1, where m{sub e} and m{sub h} are, respectively, the masses of electrons and heavy species. A new set of formulas for the transport coefficients of 2-T plasmas is obtained. The new theory has important physical and practical advantages over previous approaches. In particular, the diffusion coefficients are complete and satisfy the mass conversation law due to the consideration of the coupling between electrons and heavy species. Moreover, this essential requirement is satisfied without increasing the complexity of the transport coefficient formulas. Expressions for the 2-T combined diffusion coefficients are obtained. The expressions for the transport coefficients can be reduced to the corresponding well-established expressions for plasmas in local thermodynamic equilibrium for the case in which the electron and heavy-species temperatures are equal.

  9. Towards the understanding of non-thermal airplasma action: effects on bacteria and fibroblasts

    Czech Academy of Sciences Publication Activity Database

    Lunov, Oleg; Zablotskyy, Vitaliy A.; Churpita, Olexandr; Jäger, Aleš; Polívka, Leoš; Syková, Eva; Terebova, N.; Kulikov, A.; Kubinová, Šárka; Dejneka, Alexandr

    2016-01-01

    Roč. 6, č. 30 (2016), 25286-25292 ISSN 2046-2069 R&D Projects: GA MŠk(CZ) LM2011026; GA MŠk(CZ) LO1309 Institutional support: RVO:68378271 ; RVO:68378041 Keywords : non-thermal plasma * bactericidal effects * medical applications Subject RIV: BO - Biophysics Impact factor: 3.108, year: 2016

  10. Investigation of EBW Thermal Emission and Mode Conversion Physics in H-Mode Plasmas on NSTX

    International Nuclear Information System (INIS)

    Diem, S.J.; Taylor, G.; Efthimion, P.C.; Kugel, H.W.; LeBlanc, B.P.; Phillips, C.K.; Caughman, J.B.; Wilgen, J.B.; Harvey, R.W.; Preinhaelter, J.; Urban, J.; Sabbagh, S.A.

    2008-01-01

    High β plasmas in the National Spherical Torus Experiment (NSTX) operate in the overdense regime, allowing the electron Bernstein wave (EBW) to propagate and be strongly absorbed/emitted at the electron cyclotron resonances. As such, EBWs may provide local electron heating and current drive. For these applications, efficient coupling between the EBWs and electromagnetic waves outside the plasma is needed. Thermal EBW emission (EBE) measurements, via oblique B-X-O double mode conversion, have been used to determine the EBW transmission efficiency for a wide range of plasma conditions on NSTX. Initial EBE measurements in H-mode plasmas exhibited strong emission before the L-H transition, but the emission rapidly decayed after the transition. EBE simulations show that collisional damping of the EBW prior to the mode conversion (MC) layer can significantly reduce the measured EBE for T e < 20 eV, explaining the observations. Lithium evaporation was used to reduce EBE collisional damping near the MC layer. As a result, the measured B-X-O transmission efficiency increased from < 10% (no Li) to 60% (with Li), consistent with EBE simulations.

  11. Partial local thermal equilibrium in a low-temperature hydrogen plasma

    International Nuclear Information System (INIS)

    Hey, J.D.; Chu, C.C.; Rash, J.P.S.

    1999-01-01

    If the degree of ionisation is sufficient, competition between de-excitation by electron collisions and radiative decay determines the smallest principal quantum number (the so-called 'thermal limit') above which partial local thermodynamic equilibrium (PLTE) holds under the particular conditions of electron density and temperature. The LTE (PLTE) criteria of Wilson (JQSRT 1962;2:477-90), Griem (Phys Rev 1963;131:1170-6; Plasma Spectroscopy. New York: McGraw-Hill, 1964), Drawin (Z Physik 1969;228: 99-119), Hey (JQSRT 1976;16:69-75), and Fujimoto and McWhirter (Phys Rev A 1990;42:6588-601) are examined as regards their applicability to neutral atoms. For these purposes, we consider for simplicity an idealised, steady-state, homogeneous and primarily optically thin plasma, with some additional comments and numerical estimates on the roles of opacity and of atom-atom collisions. Particularly for atomic states of lower principal quantum number, the first two of the above criteria should be modified quite appreciably before application to neutral radiators in plasmas of low temperature, because of the profoundly different nature of the near-threshold collisional cross-sections for atoms and ions, while the most recent criterion should be applied with caution to PLTE of atoms in cold plasmas in ionisation balance. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  12. Non-thermal Power-Law Distributions in Solar and Space Plasmas

    Science.gov (United States)

    Oka, M.; Battaglia, M.; Birn, J.; Chaston, C. C.; Effenberger, F.; Eriksson, E.; Fletcher, L.; Hatch, S.; Imada, S.; Khotyaintsev, Y. V.; Kuhar, M.; Livadiotis, G.; Miyoshi, Y.; Retino, A.

    2017-12-01

    Particles are accelerated to very high, non-thermal energies in solar and space plasma environments. While energy spectra of accelerated particles often exhibit a power-law and are characterized by the power-law index δ, it remains unclear how particles are accelerated to high energies and how δ is determined. Here, we review previous observations of the power-law index δ in a variety of different plasma environments with a particular focus on sub-relativistic electrons. It appears that in regions more closely related to magnetic reconnection (such as the "above-the-looptop" solar hard X-ray source and the plasma sheet in Earth's magnetotail), the spectra are typically soft (δ> 4). This is in contrast to the typically hard spectra (δuniform in the plasma sheet, while power-law distributions still exist even in quiet times. The role of magnetotail reconnection in the electron power-law formation could therefore be confounded with these background conditions. Because different regions have been studied with different instrumentations and methodologies, we point out a need for more systematic and coordinated studies of power-law distributions for a better understanding of possible scaling laws in particle acceleration as well as their universality.

  13. A thermal transport coefficient for ohmic and ICRF plasmas in alcator C-mode

    International Nuclear Information System (INIS)

    Daughton, W.; Coppi, B.; Greenwald, M.

    1996-01-01

    The energy confinement in plasmas produced by Alcator C-Mod machine is markedly different from that observed by previous high field compact machines such as Alcator A and C, FT, and more recently FTU. For ohmic plasmas at low and moderate densities, the confinement times routinely exceed those expected from the so-called open-quotes neo-Alcatorclose quotes scaling by a factor as high as three. For both ohmic and ICRF heated plasmas, the energy confinement time increases with the current and is approximately independent of the density. The similarity in the confinement between the ohmic and ICRF regimes opens the possibility that the thermal transport in Alcator C-Mod may be described by one transport coefficient for both regimes. We introduce a modified form of a transport coefficient previously used to describe ohmic plasmas in Alcator C-Mod. The coefficient is inspired by the properties of the so-called open-quotes ubiquitousclose quotes mode that can be excited in the presence of a significant fraction of trapped electrons and also includes the constraint of profile consistency. A detailed series of transport simulations are used to show that the proposed coefficient can reproduce the observed temperature profiles, loop voltage and energy confinement time for both ohmic and ICRF discharges. A total of nearly two dozen ohmic and ICRF Alcator C-Mod discharges have been fit over the range of parameter space available using this transport coefficient

  14. Thermal Structure of Supra-Arcade Plasma in Two Solar Flares

    Science.gov (United States)

    Reeves, Katharine K.; Savage, Sabrina; McKenzie, David E.; Weber, Mark A.

    2012-01-01

    In this work, we use Hinode/XRT and SDO/AIA data to determine the thermal structure of supra-arcade plasma in two solar flares. The first flare is a Ml.2 flare that occurred on November 5, 2010 on the east limb. This flare was one of a series of flares from AR 11121, published in Reeves & Golub (2011). The second flare is an XI.7 flare that occurred on January 27, 2012 on the west limb. This flare exhibits visible supra-arcade downflows (SADs), where the November 2010 flare does not. For these two flares we combine XRT and AlA data to calculate DEMs of each pixel in the supra-arcade plasma, giving insight into the temperature and density structures in the fan of plasma above the post-flare arcade. We find in each case that the supra-arcade plasma is around 10 MK, and there is a marked decrease in the emission measure in the SADs. We also compare the DEMs calculated with the combined AIA/XRT dataset to those calculated using AIA alone.

  15. Temperature simulation of thermal plasma melting furnace for disposal of radioactive waste and preliminary research of vitrification formula

    International Nuclear Information System (INIS)

    Lin Peng; Lu Yonghong; Xiang Wenyuan; Chen Mingzhou; Liu Xiajie; Qin Yuxin

    2013-01-01

    Radioactive waste treatment techniques currently used in nuclear power plant increase the volume greatly and bring much pressure on final disposal; Thermal plasma treatment as a crucial technique to reduce the waste volume is introduced. How to improve the efficiency of the plasma energy is the limiting factor of concern. In this paper, the temperature field of thermal plasma melting furnace is simulated, the maximal temperature of fixed bed melting furnace is calculated (about 1445 ℃). According to the optional fire-resistant materials, the feasibility of furnace fabrication is discussed. Vitrification formulas for three typical radioactive wastes are tested with their feasibilities being analyzed then. Finally, the prospect of thermal plasma techniques of radioactive waste is discussed, and issues for future study are raised. (authors)

  16. Lyapunov stability and thermal stability of partially relaxed fluids and plasmas

    International Nuclear Information System (INIS)

    Elsaesser, K.; Spiess, P.

    1996-01-01

    The relation between the Lyapunov stability of a Hamiltonian system and the thermal stability of a fluid whose temperature is controlled from outside is explored: The free energy as a functional of the correct variables (specific volume, local entropy, and some Clebsch potentials of the velocity) may serve as a Lyapunov functional, depending on the open-quote open-quote Casimirs close-quote close-quote as exchanged quantities. For a multi-species plasma one obtains a sufficient condition for stability: γ(v 2 /c 2 s )-1 s the sound speed. Some features of partially relaxed (T=const) cylindrical plasmas are also discussed. copyright 1996 American Institute of Physics

  17. Synthesis of nanocrystalline magnesium nitride (Mg3N2) powder using thermal plasma

    International Nuclear Information System (INIS)

    Kim, Dong-Wook; Kim, Tae-Hee; Park, Hyun-Woo; Park, Dong-Wha

    2011-01-01

    Nanocrystalline magnesium nitride (Mg 3 N 2 ) powder was synthesized from bulk magnesium by thermal plasma at atmospheric pressure. Magnesium vapor was generated through heating the bulk magnesium by DC plasma jet and reacted with ammonia gas. Injecting position and flow rates of ammonia gas were controlled to investigate an ideal condition for Mg 3 N 2 synthesis. The synthesized Mg 3 N 2 was cooled and collected on the chamber wall. Characteristics of the synthesized powders for each experimental condition were analyzed by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and thermogravity analysis (TGA). In absence of NH 3 , magnesium metal powder was formed. The synthesis with NH 3 injection in low temperature region resulted in a formation of crystalline magnesium nitride with trigonal morphology, whereas the mixture of magnesium metal and amorphous Mg 3 N 2 was formed when NH 3 was injected in high temperature region. Also, vaporization process of magnesium was discussed.

  18. A statistical approach for predicting thermal diffusivity profiles in fusion plasmas as a transport model

    International Nuclear Information System (INIS)

    Yokoyama, Masayuki

    2014-01-01

    A statistical approach is proposed to predict thermal diffusivity profiles as a transport “model” in fusion plasmas. It can provide regression expressions for the ion and electron heat diffusivities (χ i and χ e ), separately, to construct their radial profiles. An approach that this letter is proposing outstrips the conventional scaling laws for the global confinement time (τ E ) since it also deals with profiles (temperature, density, heating depositions etc.). This approach has become possible with the analysis database accumulated by the extensive application of the integrated transport analysis suite to experiment data. In this letter, TASK3D-a analysis database for high-ion-temperature (high-T i ) plasmas in the LHD (Large Helical Device) is used as an example to describe an approach. (author)

  19. Thermal effects on tearing mode saturation

    International Nuclear Information System (INIS)

    Kim, J.S.; Chu, M.S.; Greene, J.M.

    1988-01-01

    The effect of geometry on tearing modes, saturated states of tearing modes, and the thermal effect on tearing modes are presented. The configuration of current and magnetic fields are quite different in slabs and in Tokamaks. However, for any magnetic island regardless of geometry and heating conditions, at island saturation the product of resistivity and current is the same at magnetic O and X lines. The temperature perturbation effect on the nonlinear development of tearing modes is investigated. Thermal conduction along the field lines is much faster than that in the perpendicular direction, and thus the temperature profile follows the island structure. Utilizing Spitzer's conductivity relation, the temperature perturbation is modelled as helical components of resistivity. For a usual tearing mode unstable Tokamak, where shear is positive, the islands continue to grow to a larger size when the islands are cooled. When they are heated, the island sizes are reduced. The temperature perturbation can induce islands even for equilibria stable with respect to tearing modes. Again, the islands appear when cooling takes place. The equilibria with the cooled islands show enhanced field line stochasticity, thus enhanced heat transport. Therefore, thermal instability can be directly related to pressure disruptions. (author)

  20. The interplay between biological and physical scenarios of bacterial death induced by non-thermal plasma

    Czech Academy of Sciences Publication Activity Database

    Lunov, Oleg; Zablotskyy, Vitaliy A.; Churpita, Olexandr; Jäger, Aleš; Polívka, Leoš; Syková, E.; Dejneka, Alexandr; Kubinová, Šárka

    2016-01-01

    Roč. 82, Mar (2016), s. 71-83 ISSN 0142-9612 R&D Projects: GA MŠk LO1409; GA MŠk(CZ) LM2011026 Grant - others:FUNBIO(XE) CZ.2.16/3.1.00/21568; AV ČR(CZ) Fellowship J. E. Purkyně Institutional support: RVO:68378271 Keywords : non-thermal plasma * bacteria * cytotoxicity * apoptosis * bacterial inactivation * reactive oxygen species (ROS) Subject RIV: BO - Biophysics Impact factor: 8.402, year: 2016