Laser-induced gas plasma machining

Energy Technology Data Exchange (ETDEWEB)

Elhadj, Selim; Bass, Isaac Louis; Guss, Gabriel Mark; Matthews, Manyalibo J.

2017-10-17

Techniques for removing material from a substrate are provided. A laser beam is focused at a distance from the surface to be treated. A gas is provided at the focus point. The gas is dissociated using the laser energy to generate gas plasma. The substrate is then brought in contact with the gas plasma to enable material removal.

The Use of Liquid Isopropyl Alcohol and Hydrogen Peroxide Gas Plasma to Biologically Decontaminate Spacecraft Electronics

Science.gov (United States)

Bonner, J. K.; Tudryn, Carissa D.; Choi, Sun J.; Eulogio, Sebastian E.; Roberts, Timothy J.; Tudryn, Carissa D.

2006-01-01

Legitimate concern exists regarding sending spacecraft and their associated hardware to solar system bodies where they could possibly contaminate the body's surface with terrestrial microorganisms. The NASA approved guidelines for sterilization as set forth in NPG 8020.12C, which is consistent with the biological contamination control objectives of the Committee on Space Research (COSPAR), recommends subjecting the spacecraft and its associated hardware to dry heat-a dry heat regimen that could potentially employ a temperature of 110(deg)C for up to 200 hours. Such a temperature exposure could prove detrimental to the spacecraft electronics. The stimulated growth of intermetallic compounds (IMCs) in metallic interconnects and/or thermal degradation of organic materials composing much of the hardware could take place over a prolonged temperature regimen. Such detrimental phenomena would almost certainly compromise the integrity and reliability of the electronics. Investigation of sterilization procedures in the medical field suggests that hydrogen peroxide (H202) gas plasma (HPGP) technology can effectively function as an alternative to heat sterilization, especially for heat-sensitive items. Treatment with isopropyl alcohol (IPA) in liquid form prior to exposure of the hardware to HPGP should also prove beneficial. Although IPA is not a sterilant, it is frequently used as a disinfectant because of its bactericidal properties. The use of IPA in electronics cleaning is widely recognized and has been utilized for many years with no adverse affects reported. In addition, IPA is the principal ingredient of the test fluid used in ionic contamination testers to assess the amount of ionic contamination found on the surfaces of printed wiring assemblies. This paper will set forth experimental data confirming the feasibility of the IPA/H202 approach to reach acceptable microbial reduction (MR) levels of spacecraft electronic hardware. In addition, a proposed process flow in

Diagnostics of Argon Injected Hydrogen Peroxide Added High Frequency Underwater Capillary Discharge

Directory of Open Access Journals (Sweden)

Muhammad Waqar Ahmed

2016-05-01

Full Text Available The effects of hydrogen peroxide addition and Argon injection on electrical and spectral characteristics of underwater capillary discharge were investigated. The flowing water discharge was created in a quartz tube (Φ = 4mm outer; Φ = 2mm inner; thickness 1mm by applying high frequency (25 kHz alternating current voltage (0-15kV across the tungsten electrodes (Φ=0.5mm, in pin-pin electrode configuration, separated by a gap distance of 10 mm. The results of no hydrogen peroxide addition and no Argon gas injection were compared with addition of hydrogen peroxide and Argon injection for different values. The emission spectrum was taken to present the increase in concentration of •OH radicals with and without hydrogen peroxide addition under different argon injection rates. The results demonstrated that addition of hydrogen peroxide do not remarkably affected the conductivity of water, but its addition increased the yield rate of •OH radicals generated by plasma discharge. The addition of Argon generated bubbles and gas channels reduced the high power consumption required for inducing flowing water long gap discharge. The results showed large concentration of •OH radicals due to hydrogen peroxide addition, less required input power for generating flowing water discharge by using high frequency input voltage and due to Argon injection.

Treatment of portal venous gas embolism with hyperbaric oxygen after accidental ingestion of hydrogen peroxide: a case report and review of the literature.

Science.gov (United States)

Papafragkou, Sotirios; Gasparyan, Anna; Batista, Richard; Scott, Paul

2012-07-01

It is well known that hydrogen peroxide ingestion can cause gas embolism. To report a case illustrating that the definitive, most effective treatment for gas embolism is hyperbaric oxygen therapy. We present a case of a woman who presented to the Emergency Department with acute abdominal pain after an accidental ingestion of concentrated hydrogen peroxide. Complete recovery from her symptoms occurred quickly with hyperbaric oxygen therapy. This is a case report of the successful use of hyperbaric oxygen therapy to treat portal venous gas embolism caused by hydrogen peroxide ingestion. Hyperbaric oxygen therapy can be considered for the treatment of symptomatic hydrogen peroxide ingestion. Copyright © 2012 Elsevier Inc. All rights reserved.

Effect of ambient-level gas-phase peroxides on foliar injury, growth, and net photosynthesis in Japanese radish (Raphanus sativus)

Energy Technology Data Exchange (ETDEWEB)

Chen Xuan, E-mail: xuan66chen@yahoo.co.j [Chinese Research Academy of Environmental Science, No.8, Dayangfang, Anwai, Chaoyang District, Beijing 100012 (China); Aoki, Masatoshi [Faculty of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu-shi, Tokyo 183-8509 (Japan); Takami, Akinori [National Institute for Environmental Studies, Onogawa 16-2, Tsukuba-shi, Ibaraki 305-8506 (Japan); Chai Fahe [Chinese Research Academy of Environmental Science, No.8, Dayangfang, Anwai, Chaoyang District, Beijing 100012 (China); Hatakeyama, Shiro [Faculty of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu-shi, Tokyo 183-8509 (Japan)

2010-05-15

To investigate the effects of ambient-level gas-phase peroxides concurrent with O{sub 3} on foliar injury, photosynthesis, and biomass in herbaceous plants, we exposed Japanese radish (Raphanus sativus) to clean air, 50 ppb O{sub 3}, 100 ppb O{sub 3}, and 2-3 ppb peroxides + 50 ppb O{sub 3} in outdoor chambers. Compared with exposure to 100 ppb O{sub 3}, exposure to 2-3 ppb peroxides + 50 ppb O{sub 3} induced greater damage in foliar injury, net photosynthetic rates and biomass; the pattern of foliar injury and the cause of net photosynthetic rate reduction also differed from those occurring with O{sub 3} exposure alone. These results indicate for the first time that sub-ppb peroxides + 50 ppb O{sub 3} can cause more severe damage to plants than 100 ppb O{sub 3}, and that not only O{sub 3}, but also peroxides, could be contributing to the herbaceous plant damage and forest decline observed in Japan's air-polluted urban and remote mountains areas. - Ambient-level gas-phase peroxides coexisted with 50 ppb O{sub 3} may contribute to the herbaceous plants damage and forest decline observed in Japan.

Ambient pressure microplasmas for the direct synthesis of Hydrogen Peroxide in the gas phase

NARCIS (Netherlands)

Vasko, C.A.; Bruggeman, P.J.

2011-01-01

In this work, a plasma generates hydrogen peroxide (H2O2) to be used for the insitu epoxidation of propene to propene oxide, a major bulk material in the chemical industry. Microplasmas can improve the overall cost-effectiveness of an industrial production process and are especially suitable for

Gas phase hydrogen peroxide production in atmospheric pressure glow discharges operating in He - H2O

NARCIS (Netherlands)

Vasko, C.A.; Veldhuizen, van E.M.; Bruggeman, P.J.

2013-01-01

The gas phase production of hydrogen peroxide (H2O2) in a RF atmospheric pressure glow discharge with helium and water vapour has been investigated as a function of the gas flow. It is shown that the production of H2O2 is through the recombination of two OH radicals in a three body collision and the

Relation between plasma plume density and gas flow velocity in atmospheric pressure plasma

International Nuclear Information System (INIS)

Yambe, Kiyoyuki; Taka, Shogo; Ogura, Kazuo

2014-01-01

We have studied atmospheric pressure plasma generated using a quartz tube, helium gas, and copper foil electrode by applying RF high voltage. The atmospheric pressure plasma in the form of a bullet is released as a plume into the atmosphere. To study the properties of the plasma plume, the plasma plume current is estimated from the difference in currents on the circuit, and the drift velocity is measured using a photodetector. The relation of the plasma plume density n plu , which is estimated from the current and the drift velocity, and the gas flow velocity v gas is examined. It is found that the dependence of the density on the gas flow velocity has relations of n plu ∝ log(v gas ). However, the plasma plume density in the laminar flow is higher than that in the turbulent flow. Consequently, in the laminar flow, the density increases with increasing the gas flow velocity

Non-equilibrium plasma reactor for natrual gas processing

International Nuclear Information System (INIS)

Shair, F.H.; Ravimohan, A.L.

1974-01-01

A non-equilibrium plasma reactor for natural gas processing into ethane and ethylene comprising means of producing a non-equilibrium chemical plasma wherein selective conversion of the methane in natural gas to desired products of ethane and ethylene at a pre-determined ethane/ethylene ratio in the chemical process may be intimately controlled and optimized at a high electrical power efficiency rate by mixing with a recycling gas inert to the chemical process such as argon, helium, or hydrogen, reducing the residence time of the methane in the chemical plasma, selecting the gas pressure in the chemical plasma from a wide range of pressures, and utilizing pulsed electrical discharge producing the chemical plasma. (author)

Gas-filled capillaries for plasma-based accelerators

International Nuclear Information System (INIS)

Filippi, F; Anania, M P; Brentegani, E; Biagioni, A; Chiadroni, E; Ferrario, M; Pompili, R; Romeo, S; Cianchi, A; Zigler, A

2017-01-01

Plasma Wakefield Accelerators are based on the excitation of large amplitude plasma waves excited by either a laser or a particle driver beam. The amplitude of the waves, as well as their spatial dimensions and the consequent accelerating gradient depend strongly on the background electron density along the path of the accelerated particles. The process needs stable and reliable plasma sources, whose density profile must be controlled and properly engineered to ensure the appropriate accelerating mechanism. Plasma confinement inside gas filled capillaries have been studied in the past since this technique allows to control the evolution of the plasma, ensuring a stable and repeatable plasma density distribution during the interaction with the drivers. Moreover, in a gas filled capillary plasma can be pre-ionized by a current discharge to avoid ionization losses. Different capillary geometries have been studied to allow the proper temporal and spatial evolution of the plasma along the acceleration length. Results of this analysis obtained by varying the length and the number of gas inlets will be presented. (paper)

Gas-filled capillaries for plasma-based accelerators

Science.gov (United States)

Filippi, F.; Anania, M. P.; Brentegani, E.; Biagioni, A.; Cianchi, A.; Chiadroni, E.; Ferrario, M.; Pompili, R.; Romeo, S.; Zigler, A.

2017-07-01

Plasma Wakefield Accelerators are based on the excitation of large amplitude plasma waves excited by either a laser or a particle driver beam. The amplitude of the waves, as well as their spatial dimensions and the consequent accelerating gradient depend strongly on the background electron density along the path of the accelerated particles. The process needs stable and reliable plasma sources, whose density profile must be controlled and properly engineered to ensure the appropriate accelerating mechanism. Plasma confinement inside gas filled capillaries have been studied in the past since this technique allows to control the evolution of the plasma, ensuring a stable and repeatable plasma density distribution during the interaction with the drivers. Moreover, in a gas filled capillary plasma can be pre-ionized by a current discharge to avoid ionization losses. Different capillary geometries have been studied to allow the proper temporal and spatial evolution of the plasma along the acceleration length. Results of this analysis obtained by varying the length and the number of gas inlets will be presented.

Gas injected washer plasma gun

International Nuclear Information System (INIS)

Jain, K.K.; John, P.I.; Punithavelu, A.M.; Rao, P.P.

1980-01-01

A plasma gun similar in geometry to the washer plasma gun has been operated with gas injected externally. hydrogen, nitrogen and argon plasmas have been ionised and accelerated to velocities of the order of 10 7 mm s -1 and densities 10 11 mm -3 . Higher parameter range is possible with higher electrical input power. (author)

Hydrogen peroxide safety issues

International Nuclear Information System (INIS)

Conner, W.V.

1993-01-01

A literature survey was conducted to review the safety issues involved in handling hydrogen peroxide solutions. Most of the information found in the literature is not directly applicable to conditions at the Rocky Flats Plant, but one report describes experimental work conducted previously at Rocky Flats to determine decomposition reaction-rate constants for hydrogen peroxide solutions. Data from this report were used to calculate decomposition half-life times for hydrogen peroxide in solutions containing several decomposition catalysts. The information developed from this survey indicates that hydrogen peroxide will undergo both homogeneous and heterogeneous decomposition. The rate of decomposition is affected by temperature and the presence of catalytic agents. Decomposition of hydrogen peroxide is catalyzed by alkalies, strong acids, platinum group and transition metals, and dissolved salts of transition metals. Depending upon conditions, the consequence of a hydrogen peroxide decomposition can range from slow evolution of oxygen gas to a vapor, phase detonation of hydrogen peroxide vapors

Fluorometric method for the determination of gas-phase hydrogen peroxide

Science.gov (United States)

Kok, Gregory L.; Lazrus, Allan L.

1986-01-01

The fluorometric gas-phase hydrogen peroxide procedure is based on the technique used by Lazrus et. al. for the determination of H2O2 in the liquid phase. The analytical method utilizes the reaction of H2O2 with horseradish peroxidase and p-hydroxphenylacetic acid (POPHA) to form the fluorescent dimer of POPHA. The analytical reaction responds stoichiometrically to both H2O2 and some organic hydroperoxides. To discriminate H2O2 from organic hydroperoxides, catalase is used to preferentially destroy H2O2. Using a dual-channel flow system the H2O2 concentration is determined by difference.

Gas plasma treatment: a new approach to surgery?

NARCIS (Netherlands)

Stoffels - Adamowicz, E.; Kieft, I.E.; Sladek, R.E.J.; Laan, van der E.P.; Slaaf, D.W.

2004-01-01

In this survey we analyse the status quo of gas plasma applications in medical sciences. Plasma is a partly ionized gas, which contains free charge carriers (electrons and ions), active radicals, and excited molecules. So-called nonthermal plasmas are particularly interesting, because they operate

Maize plasma membrane aquaporin ZmPIP2;5, but not ZmPIP1;2, facilitates transmembrane diffusion of hydrogen peroxide.

Science.gov (United States)

Bienert, Gerd P; Heinen, Robert B; Berny, Marie C; Chaumont, François

2014-01-01

Plant aquaporins play important roles in transmembrane water transport processes, but some also facilitate the diffusion of other small uncharged solutes ranging from gases to metalloids. Recent evidence suggests that the transmembrane movement of hydrogen peroxide, an intra- and intercellular multifunctional signaling and defense compound, can be regulated by aquaporins. We addressed the question whether maize aquaporins belonging to the plasma membrane intrinsic protein (PIP) subfamily facilitate hydrogen peroxide diffusion using heterologous expression in the yeast Saccharomyces cerevisiae. We showed that ZmPIP proteins belonging to the PIP1 and PIP2 groups were significantly expressed in yeast cells only after codon optimization of their cDNA. In accordance with previous localization studies in oocytes and plants, ZmPIP1;2 was mainly retained in intracellular membranes, while ZmPIP2;5 was localized to the plasma membrane. However, upon co-expression with ZmPIP2;5, ZmPIP1;2 was re-localized to the plasma membrane. Using a non-functional plasma membrane-localized ZmPIP2;5 mutant to deliver ZmPIP1;2 to the plasma membrane, we demonstrated that, in contrast to wild type ZmPIP2;5, ZmPIP1;2 was not permeable to hydrogen peroxide. Our study further highlighted the fact that, when using the yeast system, which is widely employed to study substrates for plant aquaporins and other transporters, although positive transport assay results allow direct conclusions to be drawn regarding solute permeability, negative results require additional control experiments to show that the protein is expressed and localized correctly before concluding on the lack of transport activity. © 2013.

Activation of peroxydisulfate by gas-liquid pulsed discharge plasma to enhance the degradation of p-nitrophenol

Science.gov (United States)

Shang, Kefeng; Wang, Hao; Li, Jie; Lu, Na; Jiang, Nan; Wu, Yan

2017-06-01

Pulsed discharge in water and over water surfaces generates ultraviolet radiation, local high temperature, shock waves, and chemical reactive species, including hydroxyl radicals, hydrogen peroxide, and ozone. Pulsed discharge plasma (PDP) can oxidize and mineralize pollutants very efficiently, but high energy consumption restricts its application for industrial wastewater treatment. A novel method for improving the energy efficiency of wastewater treatment by PDP was proposed, in which peroxydisulfate (PDS) was added to wastewater and PDS was activated by PDP to produce more strong oxidizing radicals, including sulfate radicals and hydroxyl radicals, leading to a higher oxidation capacity for the PDP system. The experimental results show that the increase in solution conductivity slightly decreased the discharge power of the pulse discharge over the water surface. An increase in the discharge intensity improved the activation of PDS and therefore the degradation efficiency and energy efficiency of p-nitrophenol (PNP). An increase in the addition dosage of PDS greatly facilitated the degradation of PNP at a molar ratio of PDS to PNP of lower than 80:1, but the performance enhancement was no longer obvious at a dosage of more than 80:1. Under an applied voltage of 20 kV and a gas discharge gap of 2 mm, the degradation efficiency and energy efficiency of the PNP reached 90.7% and 45.0 mg kWh-1 for the plasma/PDS system, respectively, which was 34% and 18.0 mg kWh-1 higher than for the discharge plasma treatment alone. Analysis of the physical and chemical effects indicated that ozone and hydrogen peroxide were important for PNP degradation and UV irradiation and heat from the discharge plasma might be the main physical effects for the activation of PDS.

Can aqueous hydrogen peroxide be used as a stand-alone energy source?

International Nuclear Information System (INIS)

Disselkamp, Robert S.

2010-01-01

A novel electrochemical scheme to convert a stand-alone supply of aqueous hydrogen peroxide into a fuel cell-ready stream of hydrogen gas plus aqueous hydrogen peroxide is described. The electrochemical cell, consisting of a solid base and solid acid electrocatalyst, together with a proton exchange membrane, comprise the system that converts aqueous hydrogen peroxide into separate gas streams of oxygen and hydrogen. Aqueous hydrogen peroxide is contained in the anode compartment only and exists in the region where oxygen gas is formed, whereas the cathode compartment is where hydrogen gas is generated and therefore exists in a reduced state. A near zero theoretical over-potential can be achieved by the choice of basicity and acidity of the electrode materials. The primary cost of the electrochemical cell is electrode construction and the aqueous hydrogen peroxide energy storage compound. Additional research effort is required to experimentally validate the concept and explore the full economic impact should initial studies, based on the design presented here, prove promising. (author)

Distortion of plasma diagnostics by an ambient gas

International Nuclear Information System (INIS)

Pearlman, J.S.; Matzen, M.K.

1978-03-01

The effect of vacuum chamber background gas on the ion measurements of a laser-produced, expanding plasma is studied over a wide range of background gas pressures. Experimental measurements are compared with calculations from a coupled rate equation-hydrodynamics code. The code is then used for a parametric study of the effect of background gas pressure on plasma diagnostic measurements. Charge exchange is found to be an important process in our diagnostics above vacuum chamber pressures of 10 -5 Torr

Anti-tumor Effects of Plasma Activated Media and Correlation with Hydrogen Peroxide Concentration

Science.gov (United States)

Laroussi, Mounir; Mohades, Soheila; Barekzi, Nazir; Maruthamuthu, Venkat; Razavi, Hamid

2016-09-01

Plasma activated media (PAM) can induce death in cancer cells. In our research, PAM is produced by exposing liquid culture medium to a helium plasma pencil. Reactive oxygen and nitrogen species in the aqueous state are known factors in anti-tumor effects of PAM. The duration of plasma exposure determines the concentrations of reactive species produced in PAM. Stability of the plasma generated reactive species and their lifetime depend on parameters such as the chemical composition of the medium. Here, a complete cell culture medium was employed to make PAM. Later, PAM was used to treat SCaBER cancer cells either as an immediate PAM (right after exposure) or as an aged-PAM (after storage). SCaBER (ATCC®HTB-3™) is an epithelial cell line from a human bladder with the squamous carcinoma disease. A normal epithelial cell line from a kidney tissue of a dog - MDCK (ATCC®CCL-34™) - was used to analyze the selective effect of PAM. Correspondingly, we measured the concentration of hydrogen peroxide- as a stable species with biological impact on cell viability- in both immediate PAM and aged-PAM. In addition, we report on the effect of serum supplemented in PAM on the H2O2 concentration measured by Amplex red assay kit. Finally, we evaluate the effects of PAM on growth and morphological changes in MDCK cells using fluorescence microscopy.

Gas Temperature Measurement in a Glow Discharge Plasma

Science.gov (United States)

Sloneker, Kenneth; Podder, Nirmol; McCurdy, William E.; Shi, Shi

2009-10-01

In this study a relatively inexpensive quartz protected thermocouple is used to measure the gas temperature in the positive column of a glow discharge plasma. For simplicity a K-type thermocouple is used to interpret the gas temperature from the sensor voltage at pressures from 0.5 Torr to 15 Torr and discharge currents from 5 mA to 120 mA. Gas temperature is investigated as a function of the gas pressure at fixed discharge currents and as a function of discharge current at fixed gas pressures in three different gas species (Ar, N2, and He). An infinite cylinder model is used to compute the average gas temperature of the discharge from joule heating and gas thermal conductivity. The model and measurement data agree within 1% to 10% depending on plasma parameters. Data for all three gases have a similar quasi-linear increasing error as compared to the model.

The role of the gas/plasma plume and self-focusing in a gas-filled capillary discharge waveguide for high-power laser-plasma applications

CERN Document Server

Ciocarlan, C.; Islam, M. R.; Ersfeld, B.; Abuazoum, S.; Wilson, R.; Aniculaesei, C.; Welsh, G. H.; Vieux, G.; Jaroszynski, D. A.; 10.1063/1.4822333

2013-01-01

The role of the gas/plasma plume at the entrance of a gas-filled capillary discharge plasma waveguide in increasing the laser intensity has been investigated. Distinction is made between neutral gas and hot plasma plumes that, respectively, develop before and after discharge breakdown. Time-averaged measurements show that the on-axis plasma density of a fully expanded plasma plume over this region is similar to that inside the waveguide. Above the critical power, relativistic and ponderomotive selffocusing lead to an increase in the intensity, which can be nearly a factor of 2 compared with the case without a plume. When used as a laser plasma wakefield accelerator, the enhancement of intensity can lead to prompt electron injection very close to the entrance of the waveguide. Self-focusing occurs within two Rayleigh lengths of the waveguide entrance plane in the region, where the laser beam is converging. Analytical theory and numerical simulations show that, for a density of 3.01018 cm3, the peak normalized...

A Plasma Control and Gas Protection System for Laser Welding of Stainless Steel

DEFF Research Database (Denmark)

Juhl, Thomas Winther; Olsen, Flemming Ove

1997-01-01

A prototype shield gas box with different plasma control nozzles have been investigated for laser welding of stainless steel (AISI 316). Different gases for plasma control and gas protection of the weld seam have been used. The gas types, welding speed and gas flows show the impact on process...... stability and protection against oxidation. Also oxidation related to special conditions at the starting edge has been investigated. The interaction between coaxial and plasma gas flow show that the coaxial flow widens the band in which the plasma gas flow suppresses the metal plasma. In this band the welds...... are oxide free. With 2.7 kW power welds have been performed at 4000 mm/min with Ar / He (70%/30%) as coaxial, plasma and shield gas....

Altered Antioxidant Status and Increased Lipid Per-Oxidation in Seminal Plasma of Tunisian Infertile Men

Science.gov (United States)

Atig, Fatma; Raffa, Monia; Ali, Habib Ben; Abdelhamid, Kerkeni; Saad, Ali; Ajina, Mounir

2012-01-01

Human seminal plasma is a natural reservoir of antioxidants that protect spermatozoa from oxidative damages. There is evidence in literature supports the fact that impairments in seminal antioxidant and lipid per-oxidation status play important roles in the physiopathology of male infertility. Our present study forms the first one which was carried out in Tunisia. We evaluated the antioxidant status in the seminal plasma of 120 infertile men programmed to In Vitro Fertilization (IVF) for the first tentative. Patients were characterized by an idiopathic infertility. They were divided into three groups: normozoospermics who were considered as controls (n=40), asthenozoospermics (Astheno; n=45) and oligoasthenoteratozoospermics (OAT; n=35). Seminal activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX) and the levels of glutathione (GSH), zinc (Zn) and malondialdehyde (MDA) were measured. With the significant increase of the seminal activities of SOD and GPX in normozoospermics group, there were positive correlations observed between this enzymes and sperm quality. Also, significant elevated rates of seminal zinc and GSH were observed in control group, but there was contradictory associations reflecting the effects of these antioxidants on semen parameters. However, we noted significant increase of MDA levels in groups with abnormal seminogram. We showed negative associations between this per-oxidative marker and sperm parameters. These results obviously suggested that impairment on seminal antioxidants is an important risk factor for low sperm quality associated to idiopathic infertility and as a result can lead to poor IVF outcome. PMID:22211112

Plasma-neutral gas interaction in a tokamak divertor: effects of hydrogen molecules and plasma recombination

International Nuclear Information System (INIS)

Krasheninnikov, S.I.; Pigarov, A.Yu.; Soboleva, T.K.; Sigmar, D.J.

1997-01-01

We investigate the influence of hydrogen molecules on plasma recombination using a collisional-radiative model for multispecies hydrogen plasmas and tokamak detached divertor parameters. The rate constant found for molecular activated recombination of a plasma can be as high as 2 x 10 -10 cm 3 /s, confirming our pervious estimates. We investigate the effects of hydrogen molecules and plasma recombination on self-consistent plasma-neutral gas interactions in the recycling region of a tokamak divertor. We treat the plasma flow in a fluid approximation retaining the effects of plasma recombination and employing a Knudsen neutral transport model for a 'gas box' divertor geometry. For the model of plasma-neutral interactions we employ we find: (a) molecular activated recombination is a dominant channel of divertor plasma recombination; and (b) plasma recombination is a key element leading to a decrease in the plasma flux onto the target and substantial plasma pressure drop which are the main features of detached divertor regimes. (orig.)

Inactivation of possible microorganism food contaminants on packaging foils using nonthermal plasma and hydrogen peroxide

International Nuclear Information System (INIS)

Scholtz, V.; Khun, J.; Soušková, H.; Čeřovský, M.

2015-01-01

The inactivation effect of nonthermal plasma generated in electric discharge burning in air atmosphere with water or hydrogen peroxide aerosol for the application to the microbial decontamination of packaging foils is studied. The microbial inactivation is studied on two bacterial, two yeasts, and two filamentous micromycete species. The inactivation of all contaminating microorganisms becomes on the area of full 8.5 cm in diameter circular sample after short times of several tens of seconds. Described apparatus may present a possible alternative method of microbial decontamination of food packaging material or other thermolabile materials

Inactivation of possible microorganism food contaminants on packaging foils using nonthermal plasma and hydrogen peroxide

Energy Technology Data Exchange (ETDEWEB)

Scholtz, V., E-mail: Vladimir.Scholtz@vscht.cz; Khun, J. [Institute of Chemical Technology in Prague, Department of Physics and Measurements, Faculty of Chemical Engineering (Czech Republic); Soušková, H. [Institute of Chemical Technology in Prague, Department of Computing and Control Engineering, Faculty of Chemical Engineering (Czech Republic); Čeřovský, M. [Institute of Chemical Technology in Prague, Department of Food Preservation, Faculty of Food and Biochemical Technology (Czech Republic)

2015-07-15

The inactivation effect of nonthermal plasma generated in electric discharge burning in air atmosphere with water or hydrogen peroxide aerosol for the application to the microbial decontamination of packaging foils is studied. The microbial inactivation is studied on two bacterial, two yeasts, and two filamentous micromycete species. The inactivation of all contaminating microorganisms becomes on the area of full 8.5 cm in diameter circular sample after short times of several tens of seconds. Described apparatus may present a possible alternative method of microbial decontamination of food packaging material or other thermolabile materials.

Increased plasma peroxides as a marker of oxidative stress in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

OpenAIRE

Maes, Michael; Kubera, Marta; Uytterhoeven, Marc; Vrydags, Nicolas; Bosmans, Eugene

2011-01-01

Summary Background There is evidence that myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by activation of immune, inflammatory, oxidative and nitrosative stress (IO&NS) pathways. The present study was carried out in order to examine whether ME/CFS is accompanied by increased levels of plasma peroxides and serum oxidized LDL (oxLDL) antibodies, two biomarkers of oxidative stress. Material/Methods Blood was collected from 56 patients with ME/CFS and 37 normal volun...

Perioperative intravenous acetaminophen attenuates lipid peroxidation in adults undergoing cardiopulmonary bypass: a randomized clinical trial.

Directory of Open Access Journals (Sweden)

Frederic T Billings

Full Text Available Cardiopulmonary bypass (CPB lyses erythrocytes and induces lipid peroxidation, indicated by increasing plasma concentrations of free hemoglobin, F2-isoprostanes, and isofurans. Acetaminophen attenuates hemeprotein-mediated lipid peroxidation, reduces plasma and urine concentrations of F2-isoprostanes, and preserves kidney function in an animal model of rhabdomyolysis. Acetaminophen also attenuates plasma concentrations of isofurans in children undergoing CPB. The effect of acetaminophen on lipid peroxidation in adults has not been studied. This was a pilot study designed to test the hypothesis that acetaminophen attenuates lipid peroxidation in adults undergoing CPB and to generate data for a clinical trial aimed to reduce acute kidney injury following cardiac surgery.In a prospective double-blind placebo-controlled clinical trial, sixty adult patients were randomized to receive intravenous acetaminophen or placebo starting prior to initiation of CPB and for every 6 hours for 4 doses. Acetaminophen concentrations measured 30 min into CPB and post-CPB were 11.9 ± 0.6 μg/mL (78.9 ± 3.9 μM and 8.7 ± 0.3 μg/mL (57.6 ± 2.0 μM, respectively. Plasma free hemoglobin increased more than 15-fold during CPB, and haptoglobin decreased 73%, indicating hemolysis. Plasma and urinary markers of lipid peroxidation also increased during CPB but returned to baseline by the first postoperative day. Acetaminophen reduced plasma isofuran concentrations over the duration of the study (P = 0.05, and the intraoperative plasma isofuran concentrations that corresponded to peak hemolysis were attenuated in those subjects randomized to acetaminophen (P = 0.03. Perioperative acetaminophen did not affect plasma concentrations of F2-isoprostanes or urinary markers of lipid peroxidation.Intravenous acetaminophen attenuates the increase in intraoperative plasma isofuran concentrations that occurs during CPB, while urinary markers were unaffected.ClinicalTrials.gov NCT

Clinical symptoms in fibromyalgia are better associated to lipid peroxidation levels in blood mononuclear cells rather than in plasma.

Science.gov (United States)

Cordero, Mario D; Alcocer-Gómez, Elísabet; Cano-García, Francisco J; De Miguel, Manuel; Carrión, Angel M; Navas, Plácido; Sánchez Alcázar, José A

2011-01-01

We examined lipid peroxidation (LPO) in blood mononuclear cells (BMCs) and plasma, as a marker of oxidative damage, and its association to clinical symptoms in Fibromyalgia (FM) patients. We conducted a case-control and correlational study comparing 65 patients and 45 healthy controls. Clinical parameters were evaluated using the Fibromyalgia Impact Questionnaire (FIQ), visual analogues scales (VAS), and the Beck Depression Inventory (BDI). Oxidative stress was determined by measuring LPO in BMCs and plasma. We found increased LPO levels in BMCs and plasma from FM patients as compared to normal control (PBMI, and sex, showed that both LPO in cells and plasma were independently associated to clinical symptoms. However, LPO in cells, but not LPO in plasma, was independently associated to clinical symptoms when controlling for depression (BDI scores). The results of this study suggest a role for oxidative stress in the pathophysiology of fibromyalgia and that LPO in BMCs rather than LPO in plasma is better associated to clinical symptoms in FM.

Operation of Ferroelectric Plasma Sources in a Gas Discharge Mode

International Nuclear Information System (INIS)

Dunaevsky, A.; Fisch, N.J.

2004-01-01

Ferroelectric plasma sources in vacuum are known as sources of ablative plasma, formed due to surface discharge. In this paper, observations of a gas discharge mode of operation of the ferroelectric plasma sources (FPS) are reported. The gas discharge appears at pressures between approximately 20 and approximately 80 Torr. At pressures of 1-20 Torr, there is a transition from vacuum surface discharge to the gas discharge, when both modes coexist and the surface discharges sustain the gas discharge. At pressures between 20 and 80 Torr, the surface discharges are suppressed, and FPS operate in pure gas discharge mode, with the formation of almost uniform plasma along the entire surface of the ceramics between strips. The density of the expanding plasma is estimated to be about 1013 cm-3 at a distance of 5.5 mm from the surface. The power consumption of the discharge is comparatively low, making it useful for various applications. This paper also presents direct measurements of the yield of secondary electron emission from ferroelectric ceramics, which, at low energies of primary electrons, is high and dependent on the polarization of the ferroelectric material

Study on dynamics of the influence exerted by plasma on gas flow field in non-thermal atmospheric pressure plasma jet

Energy Technology Data Exchange (ETDEWEB)

Qaisrani, M. Hasnain; Xian, Yubin, E-mail: yubin.xian@hotmail.com; Li, Congyun; Pei, Xuekai; Ghasemi, Maede; Lu, Xinpei [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

2016-06-15

In this paper, first, steady state of the plasma jet at different operating conditions is investigated through Schlieren photography with and without applying shielding gas. Second, the dynamic process for the plasma impacting on the gas flow field is studied. When the discharge is ignited, reduction in laminar flow occurs. However, when the gas flow rate is too low or too high, this phenomenon is not obvious. What is more, both frequency and voltage have significant impact on the effect of plasma on the gas flow, but the former is more significant. Shielding gas provides a curtain for plasma to propagate further. High speed camera along with Schlieren photography is utilized to study the impact of plasma on the gas flow when plasma is switched on and off. The transition of the gas flow from laminar to turbulent or vice versa happens right after the turbulent front. It is concluded that appearance and propagation of turbulence front is responsible for the transition of the flow state.

Fuel gas production by microwave plasma in liquid

International Nuclear Information System (INIS)

Nomura, Shinfuku; Toyota, Hiromichi; Tawara, Michinaga; Yamashita, Hiroshi; Matsumoto, Kenya

2006-01-01

We propose to apply plasma in liquid to replace gas-phase plasma because we expect much higher reaction rates for the chemical deposition of plasma in liquid than for chemical vapor deposition. A reactor for producing microwave plasma in a liquid could produce plasma in hydrocarbon liquids and waste oils. Generated gases consist of up to 81% hydrogen by volume. We confirmed that fuel gases such as methane and ethylene can be produced by microwave plasma in liquid

Gas and particle velocity measurements in an induction plasma

International Nuclear Information System (INIS)

Lesinski, J.; Gagne, R.; Boulos, M.I.

1981-08-01

Laser doppler anemometry was used for the measurements of the plasma and particle velocity profiles in the coil region of an inductively coupled plasma. Results are reported for a 50 mm ID induction torch operated at atmospheric pressure with argon as the plasma gas. The oscillator frequency was 3 MHz and the power in the coil was varied between 4.6 and 10.5 kW. The gas velocity measurements were made using a fine carbon powder as a tracer (dp approx. = 1 μm). Measurements were also made with larger silicon particles (dp = 33 μm and sigma = 13 μm) centrally injected in the plasma under different operating conditions

Rotation of a magnesium plasma column in a background gas

International Nuclear Information System (INIS)

Bosco, E. Del; Dallaqua, R.S.

1993-01-01

Measurements of the angular velocity of a plasma column in a surrounding gas atmosphere are presented. The plasma is produced by a pulsed, high current arc discharge in the presence of an axial magnetic field. The angular velocity is measured using the cross correlation technique applied to the floating potential signals measured by two Langmuir probes. The main result is that when gas is added to the discharge the angular velocity is always lower than the case when there is no gas, this effect been more pronounced in the beginning of the discharge. For pressures higher than ∼ 2 x 10 -2 Pa there is a effect of the gas on the plasma column rotation and the angular velocity diminishes even at the end of discharge. (author)

Ideal gas behavior of a strongly coupled complex (dusty) plasma.

Science.gov (United States)

Oxtoby, Neil P; Griffith, Elias J; Durniak, Céline; Ralph, Jason F; Samsonov, Dmitry

2013-07-05

In a laboratory, a two-dimensional complex (dusty) plasma consists of a low-density ionized gas containing a confined suspension of Yukawa-coupled plastic microspheres. For an initial crystal-like form, we report ideal gas behavior in this strongly coupled system during shock-wave experiments. This evidence supports the use of the ideal gas law as the equation of state for soft crystals such as those formed by dusty plasmas.

Ideal gas behavior of a strongly-coupled complex (dusty) plasma

OpenAIRE

Oxtoby, Neil P.; Griffith, Elias J.; Durniak, Céline; Ralph, Jason F.; Samsonov, Dmitry

2012-01-01

In a laboratory, a two-dimensional complex (dusty) plasma consists of a low-density ionized gas containing a confined suspension of Yukawa-coupled plastic microspheres. For an initial crystal-like form, we report ideal gas behavior in this strongly-coupled system during shock-wave experiments. This evidence supports the use of the ideal gas law as the equation of state for soft crystals such as those formed by dusty plasmas.

Electron energy distribution function control in gas discharge plasmas

International Nuclear Information System (INIS)

Godyak, V. A.

2013-01-01

The formation of the electron energy distribution function (EEDF) and electron temperature in low temperature gas discharge plasmas is analyzed in frames of local and non-local electron kinetics. It is shown, that contrary to the local case, typical for plasma in uniform electric field, there is the possibility for EEDF modification, at the condition of non-local electron kinetics in strongly non-uniform electric fields. Such conditions “naturally” occur in some self-organized steady state dc and rf discharge plasmas, and they suggest the variety of artificial methods for EEDF modification. EEDF modification and electron temperature control in non-equilibrium conditions occurring naturally and those stimulated by different kinds of plasma disturbances are illustrated with numerous experiments. The necessary conditions for EEDF modification in gas discharge plasmas are formulated

Experimental investigation of gas heating and dissociation in a microwave plasma torch at atmospheric pressure

International Nuclear Information System (INIS)

Su, Liu; Kumar, Rajneesh; Ogungbesan, Babajide; Sassi, Mohamed

2014-01-01

Highlights: • Atmospheric-pressure microwave plasma torch. • Gas heating and dissociation. • Parametric studies of plasma operating conditions. • Local thermal equilibrium plasma. - Abstract: Experimental investigations are made to understand gas heating and dissociation in a microwave (MW) plasma torch at atmospheric pressure. The MW induced plasma torch operates at 2.45 GHz frequency and up to 2 kW power. Three different gas mixtures are injected in the form of axial flow and swirl flow in a quartz tube plasma torch to experimentally investigate the MW plasma to gas energy transfer. Air–argon, air–air and air–nitrogen plasmas are formed and their operational ranges are determined in terms of gas flow rates and MW power. Visual observations, optical emission spectroscopy and K-type thermocouple measurements are used to characterize the plasma. The study reveals that the plasma structure is highly dependent on the carrier gas type, gas flow rate, and MW power. However, the plasma gas temperature is shown not to vary much with these parameters. Further spectral and analytical analysis show that the plasma is in thermal equilibrium and presents very good energy coupling between the microwave power and gas heating and dissociation. The MW plasma torch outlet temperature is also measured and found to be suitable for many thermal heating and chemical dissociation applications

Whistleron gas in magnetized plasmas

International Nuclear Information System (INIS)

De Martino, Salvatore; Falanga, Mariarosaria; Tzenov, Stephan I.

2005-01-01

The nonlinear dynamics of whistler waves in magnetized plasmas is studied. Since the plasmas and beam-plasma systems considered here are assumed to be weakly collisional, the point of reference for the analysis performed in the present paper is the system of hydrodynamic and field equations. The renormalization group method is applied to obtain dynamical equations for the slowly varying amplitudes of whistler waves. Further, it has been shown that the amplitudes of eigenmodes satisfy an infinite system of coupled nonlinear Schroedinger equations. In this sense, the whistler eigenmodes form a sort of a gas of interacting quasiparticles, while the slowly varying amplitudes can be considered as dynamical variables heralding the relevant information about the system. An important feature of the approach is that whistler waves do not perturb the initial uniform density of plasma electrons. The plasma response to the induced whistler waves consists in velocity redistribution which follows exactly the behavior of the whistlers. In addition, selection rules governing the nonlinear mode coupling have been derived, which represent another interesting peculiarity of the description presented here

Lipid peroxidation and ascorbic acid levels in Nigeria children with ...

African Journals Online (AJOL)

This study was undertaken to establish data on the roles of lipid peroxidation and ascorbic acid in the pathology of malaria in Nigeria children. We measured the levels of malondialdehyde (MDA), a marker of lipid peroxidation and ascorbic acid in the plasma of 406 parasitaemic and 212 non-parasitaemic Nigerian children.

Transition of RF internal antenna plasma by gas control

Energy Technology Data Exchange (ETDEWEB)

Hamajima, Takafumi; Yamauchi, Toshihiko; Kobayashi, Seiji; Hiruta, Toshihito; Kanno, Yoshinori [Advanced Institute of Industrial Technology, 1-10-40 HigashiOhi, Shinagawa-ku, Tokyo, 140-0011 (Japan); Japan Atomic Energy Agency, 2-4 Tokai-mura, Naka-gun, Ibaraki-ken, 319-1195 (Japan)

2012-07-11

The transition between the capacitively coupled plasma (CCP) and the inductively coupled plasma (ICP) was investigated with the internal radio frequency (RF) multi-turn antenna. The transition between them showed the hysteresis curve. The radiation power and the period of the self-pulse mode became small in proportion to the gas pressure. It was found that the ICP transition occurred by decreasing the gas pressure from 400 Pa.

An argon–nitrogen–hydrogen mixed-gas plasma as a robust ionization source for inductively coupled plasma mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Makonnen, Yoseif; Beauchemin, Diane, E-mail: diane.beauchemin@chem.queensu.ca

2014-09-01

Multivariate optimization of an argon–nitrogen–hydrogen mixed-gas plasma for minimum matrix effects, while maintaining analyte sensitivity as much as possible, was carried out in inductively coupled plasma mass spectrometry. In the presence of 0.1 M Na, the 33.9 ± 3.9% (n = 13 elements) analyte signal suppression on average observed in an all-argon plasma was alleviated with the optimized mixed-gas plasma, the average being − 4.0 ± 8.8%, with enhancement in several cases. An addition of 2.3% v/v N{sub 2} in the outer plasma gas, and 0.50% v/v H{sub 2} to the central channel, as a sheath around the nebulizer gas flow, was sufficient for this drastic increase in robustness. It also reduced the background from ArO{sup +} and Ar{sub 2}{sup +} as well as oxide levels by over an order of magnitude. On the other hand, the background from NO{sup +} and ArN{sup +} increased by up to an order of magnitude while the levels of doubly-charged ions increased to 7% (versus 2.7% in an argon plasma optimized for sensitivity). Furthermore, detection limits were generally degraded by 5 to 15 fold when using the mixed-gas plasma versus the argon plasma for matrix-free solution (although they were better for several elements in 0.1 M Na). Nonetheless, the drastically increased robustness allowed the direct quantitative multielement analysis of certified ore reference materials, as well as the determination of Mo and Cd in seawater, without using any matrix-matching or internal standardization. - Highlights: • Addition of N{sub 2} to the plasma gas and H{sub 2} as a sheath gas results in a very robust ICP. • ArO{sup +} and Ar{sub 2}{sup +} background and oxide levels are reduced by over an order of magnitude. • Multielement analysis of rock digests is possible with a simple external calibration. • No internal standardization or matrix-matching is required for accurate analysis. • Cd and Mo were accurately determined in undiluted seawater.

Reactive gas control of non-stable plasma conditions

International Nuclear Information System (INIS)

Bellido-Gonzalez, V.; Daniel, B.; Counsell, J.; Monaghan, D.

2006-01-01

Most industrial plasma processes are dependant upon the control of plasma properties for repeatable and reliable production. The speed of production and range of properties achieved depend on the degree of control. Process control involves all the aspects of the vacuum equipment, substrate preparation, plasma source condition, power supplies, process drift, valves (inputs/outputs), signal and data processing and the user's understanding and ability. In many cases, some of the processes which involve the manufacturing of interesting coating structures, require a precise control of the process in a reactive environment [S.J. Nadel, P. Greene, 'High rate sputtering technology for throughput and quality', International Glass Review, Issue 3, 2001, p. 45. ]. Commonly in these circumstances the plasma is not stable if all the inputs and outputs of the system were to remain constant. The ideal situation is to move a process from set-point A to B in zero time and maintain the monitored signal with a fluctuation equal to zero. In a 'real' process that's not possible but improvements in the time response and energy delivery could be achieved with an appropriate algorithm structure. In this paper an advanced multichannel reactive plasma gas control system is presented. The new controller offers both high-speed gas control combined with a very flexible control structure. The controller uses plasma emission monitoring, target voltage or any process sensor monitoring as the input into a high-speed control algorithm for gas input. The control algorithm and parameters can be tuned to different process requirements in order to optimize response times

Inhibition of radiation-induced lipid peroxidation by means of gallic polydisulphide

International Nuclear Information System (INIS)

Losev, Yu.P.; Amadyan, M.G.; Oganesyan, N.M.; Fedulov, A.S.; Abramyan, A.K.; Shagoyan, A.G.; Khachkavanktsyan, A.S.

1999-01-01

Inhibition of radiation-induced lipid peroxidation by means of gallic polydisulphade has been studied. Rats were exposed to X-rays in doses 4,8 and 5,25 Gy. Lipid peroxidation was analysed in blood plasma, membranes of erythrocytes and homogenates of liver and spleen tissues of rats. Polydisulphide of gallic acid was used as inhibitor of lipid peroxidation because of its effective antioxidant properties as have been reported previously. It has been demonstrated that gallic disulphide exhibited high inhibition efficiency in conditions of radiation-induced lipid peroxidation due to the effect of intra-molecular synergism

Investigation of Sterilization Mechanism for Geobacillus stearothermophilus Spores with Plasma-Excited Neutral Gas

Science.gov (United States)

Matsui, Kei; Ikenaga, Noriaki; Sakudo, Noriyuki

2015-09-01

We investigate the mechanism of the sterilization with plasma-excited neutral gas that uniformly sterilizes both the space and inner wall of the reactor chamber at atmospheric pressure. Only reactive neutral species such as plasma-excited gas molecules and radicals are separated from the plasma and sent to the reactor chamber for chemical sterilization. The plasma source gas uses humidified mixture of nitrogen and oxygen. Geobacillus stearothermophilus spores and tyrosine which is amino acid are treated by the plasma-excited neutral gas. Shape change of the treated spore is observed by SEM, and chemical modification of the treated tyrosine is analyzed by HPLC. As a result, the surface of the treated spore shows depression. Hydroxylation and nitration of tyrosine are shown after the treatment. For these reasons, we believe that the sterilization with plasma-excited neutral gas results from the deformation of spore structure due to the chemical modification of amino acid.

Oral and intraperitoneal administration of quercetin decreased lymphocyte DNA damage and plasma lipid peroxidation induced by TSA in vivo.

Science.gov (United States)

Chan, Shu-Ting; Lin, Yi-Chin; Chuang, Cheng-Hung; Shiau, Rong-Jen; Liao, Jiunn-Wang; Yeh, Shu-Lan

2014-01-01

Our previous study showed that quercetin enhances the anticancer effect of trichostatin A (TSA) in xenograft mice given quercetin intraperitoneally (10 mg/kg, 3 times/week). Herein, we investigate whether quercetin administered orally exerts such an effect and prevents the cytotoxic side effects of TSA. We found that quercetin given orally (20 and 100 mg/kg, 3 times/week) failed to enhance the antitumor effect of TSA although it increased the total quercetin concentration more than quercetin administered intraperitoneally in the plasma. The compound quercetin-3-glucuronide (Q3G) increased the most. However, quercetin administered intraperitoneally increased the total quercetin level in tumor tissues more than oral quercetin. Oral and intraperitoneal administration of quercetin similarly decreased lymphocyte DNA damage and plasma lipid peroxidation level induced by TSA. Furthermore, we found that the enhancing effect of Q3G on the antitumor effect of TSA and the incorporation of Q3G was less than that of quercetin in A549 cells. However, we found that A549 cells possessed the ability to convert Q3G to quercetin. In conclusion, different from quercetin administered intraperitoneally, quercetin administered orally failed to enhance the antitumor effect of TSA because of its metabolic conversion. However, it prevented TSA-induced DNA damage and lipid peroxidation.

Plasma performance improvement with neon gas puffing in HT-7

International Nuclear Information System (INIS)

Gong, X.; Wan, B.; Li, J.; Shi, Y.; Zhang, X.; Zhu, Y.; Wu, Z.; Liu, H.; Qian, J.

2005-01-01

The neon gas puffing for the production of a radiative layer near the plasma edge with the improved energy and particle confinement has been investigated in HT-7 during the 2003 campaign. Plasma characteristics of these discharges in HT-7 are similar to the TEXTOR RI-mode discharges. The peaked electron temperature and the broadened density profiles were formed in these discharges with the combination of LHCD and IBW heating. The central electron temperature was increased by nearly 50%, compared those discharges with the same plasma parameters and injected power without the neon gas puffing. These discharges also exhibited relatively higher plasma inductance. (author)

Microwave atmospheric pressure plasma jets for wastewater treatment: Degradation of methylene blue as a model dye.

Science.gov (United States)

García, María C; Mora, Manuel; Esquivel, Dolores; Foster, John E; Rodero, Antonio; Jiménez-Sanchidrián, César; Romero-Salguero, Francisco J

2017-08-01

The degradation of methylene blue in aqueous solution as a model dye using a non thermal microwave (2.45 GHz) plasma jet at atmospheric pressure has been investigated. Argon has been used as feed gas and aqueous solutions with different concentrations of the dye were treated using the effluent from plasma jet in a remote exposure. The removal efficiency increased as the dye concentration decreased from 250 to 5 ppm. Methylene blue degrades after different treatment times, depending on the experimental plasma conditions. Thus, kinetic constants up to 0.177 min -1 were obtained. The higher the Ar flow, the faster the degradation rate. Optical emission spectroscopy (OES) was used to gather information about the species present in the gas phase, specifically excited argon atoms. Argon excited species and hydrogen peroxide play an important role in the degradation of the dye. In fact, the conversion of methylene blue was directly related to the density of argon excited species in the gas phase and the concentration of hydrogen peroxide in the aqueous liquid phase. Values of energy yield at 50% dye conversion of 0.296 g/kWh were achieved. Also, the use of two plasma applicators in parallel has been proven to improve energy efficiency. Copyright © 2017 Elsevier Ltd. All rights reserved.

Shock waves in gas and plasma

International Nuclear Information System (INIS)

Niu, K.

1996-01-01

A shock wave is a discontinuous surface that connects supersonic flow with subsonic flow. After a shock wave, flow velocity is reduced, and pressure and temperature increase; entropy especially increases across a shock wave. Therefore, flow is in nonequilibrium, and irreversible processes occur inside the shock layer. The thickness of a shock wave in neutral gas is of the order of the mean free path of the fluid particle. A shock wave also appears in magnetized plasma. Provided that when the plasma flow is parallel to the magnetic field, a shock wave appears if the governing equation for velocity potential is in hyperbolic type in relation with the Mach number and the Alfven number. When the flow is perpendicular to the magnetic field, the Maxwell stress, in addition to the pressure, plays a role in the shock wave in plasma. When the plasma temperature is so high, as the plasma becomes collision-free, another type of shock wave appears. In a collision-free shock wave, gyromotions of electrons around the magnetic field lines cause the shock formation instead of collisions in a collision-dominant plasma or neutral gas. Regardless of a collision-dominant or collision-free shock wave, the fluid that passes through the shock wave is heated in addition to being compressed. In inertial confinement fusion, the fuel must be compressed. Really, implosion motion performs fuel compression. A shock wave, appearing in the process of implosion, compresses the fuel. The shock wave, however, heats the fuel more intensively, and it makes it difficult to compress the fuel further because high temperatures invite high pressure. Adiabatic compression of the fuel is the desired result during the implosion, without the formation of a shock wave. (Author)

Plasma and neutral gas jet interactions in the exhaust of a magnetic confinement system

International Nuclear Information System (INIS)

Krueger, W.A.

1990-06-01

A general purpose 2-1/2 dimensional, multifluid, time dependent computer code has been developed. This flexible tool models the dynamic behavior of plasma/neutral gas interactions in the presence of a magnetic field. The simulation has been used to examine the formation of smoke ring structure in the plasma rocket exhaust by injection of an axial jet of neutral gas. Specifically, the code was applied to the special case of attempting to couple the neutral gas momentum to the plasma in such a manner that plasma smoke rings would form, disconnecting the plasma from the magnetic field. For this scenario several cases where run scanning a wide range of neutral gas input parameters. In all the cases it was found that after an initial transient phase, the plasma eroded the neutral gas and after that followed the original magnetic field. From these findings it is concluded that smoke rings do not form with axial injection of neutral gas. Several suggestions for alternative injection schemes are presented

Differential sensitivity of cellular membranes to peroxidative processes

International Nuclear Information System (INIS)

Huijbers, W.A.R.

1976-01-01

A description is given of a morphological and cytochemical investigation into the effects of both vitamin E deficiency and X-irradiation on the ultrastructure and enzyme activities of several cellular membranes, particularly the plasma membrane and the membranes of lysosomes, mitochondria and endoplasmic reticulum. In the vitamin E deficient situation, the radicals and peroxides only originate near mitochondria and endoplasmic reticulum, so that these membrane systems suffer from changes. After irradiation of the liver of both the control duckling and the deficient duckling, radicals originate in all parts of the cell. Due to their high content of lipids and cholesterols, peroxides will occur mainly in plasma membranes and lysosomal membranes. Moreover, in these membranes there is hardly any protection by vitamin E

Velocities of gas and plasmas from real time holographic interferograms

International Nuclear Information System (INIS)

Deason, V.A.; Reynolds, L.D.; McIlwain, M.E.

1985-01-01

A truly noninvasive measurement technique for plasma velocity has not been demonstrated. Plasma velocities have been inferred using laser Doppler anemometry or photographic analysis of the position of smoke or small particles. This paper describes an alternate method based on the refractive index change created in a plasma by a gaseous probe material injected into the plasma. This disturbance of the refractive index can be monitored using interferometry. A multipass real time holographic interferometry system was used to follow the changes of the interferometric pattern, and the data was recorded using high speed cinematography. A transparent model of an industrial plasma torch was employed in these studies, and a number of different types of trace gas materials were used to track the plasma flow. Using a combination of multipass interferometry and a laser line absorbing gas, sufficient interferometric sensitivity was obtained to determine plasma velocities in the 100 m/s range. Based on these results, a working plasma torch was constructed. Further studies are planned using this torch and actual plasmas

Propagation of atmospheric pressure helium plasma jet into ambient air at laminar gas flow

Science.gov (United States)

Pinchuk, M.; Stepanova, O.; Kurakina, N.; Spodobin, V.

2017-05-01

The formation of an atmospheric pressure plasma jet (APPJ) in a gas flow passing through the discharge gap depends on both gas-dynamic properties and electrophysical parameters of the plasma jet generator. The paper presents the results of experimental and numerical study of the propagation of the APPJ in a laminar flow of helium. A dielectric-barrier discharge (DBD) generated inside a quartz tube equipped with a coaxial electrode system, which provided gas passing through it, served as a plasma source. The transition of the laminar regime of gas flow into turbulent one was controlled by the photography of a formed plasma jet. The corresponding gas outlet velocity and Reynolds numbers were revealed experimentally and were used to simulate gas dynamics with OpenFOAM software. The data of the numerical simulation suggest that the length of plasma jet at the unvarying electrophysical parameters of DBD strongly depends on the mole fraction of ambient air in a helium flow, which is established along the direction of gas flow.

Statistical dynamics of transient processes in a gas discharge plasma

International Nuclear Information System (INIS)

Smirnov, G.I.; Telegin, G.G.

1991-01-01

The properties of a gas discharge plasma to a great extent depend on random processes whose study has recently become particularly important. The present work is concerned with analyzing the statistical phenomena that occur during the prebreakdown stage in a gas discharge. Unlike other studies of breakdown in the discharge gap, in which secondary electron effects and photon processes at the electrodes must be considered, here the authors treat the case of an electrodeless rf discharge or a laser photoresonant plasma. The analysis is based on the balance between the rates of electron generation and recombination in the plasma. The fluctuation kinetics for ionization of atoms in the hot plasma may also play an important role when the electron temperature changes abruptly, as occurs during adiabatic pinching of the plasma or during electron cyclotron heating

Structure of anode plasma of gas discharge taking into account gas ionization burnout

International Nuclear Information System (INIS)

Zharinov, A.V.; Shumilin, V.P.

2006-01-01

One deals with a structure of an anode plasma of a gas discharge with intensive ionization ( b urnout ) of neutral atoms (neutrals). One derived analytical solutions of the quasi-neutrality equation for potential distribution, as well as, a condition of anode plasma existence in a unidimensional case at the arbitrary dependences of neutral burnout frequency and of electron concentration on the potential. One studied particular cases of the level frequency of neutral burnout, of ionization by the Maxwell electrons and of ionization by the intensive beam at collision-free motion of ions and the Boltzmann distribution of thermal electrons. Solutions for the first two cases at zero parameter of burnout, that is, at the level concentration of a gas coincide with the solutions obtained [1] by the power series expansion. It is shown that in case of ionization by the Maxwell electrons, anode plasma at the rational flow rates of a working gas may be produced under rather high temperature of electrons (if, for example, xenon serves as a working gas, so T e ≥5 eV). The stationary solutions of the quasi-neutrality at ionization by the intensive electron beam are found exclusively when the ratio between the electron beam density and the maximum density of thermal neutrons does not exceed a certain limiting value [ru

The Effect of Percentage of Nitrogen in Plasma Gas on Nitrogen ...

African Journals Online (AJOL)

Increase in nitrogen percent in the plasma gas results in increased content of dissociated nitrogen and molecular nitrogen possessing excess vibrational energy and therefore the increased solution of nitrogen in the liquid iron. It would appear that above 35% nitrogen in the plasma gas, frequency of collisions of species in ...

Controlling hydrophilicity of polymer film by altering gas flow rate in atmospheric-pressure homogeneous plasma

International Nuclear Information System (INIS)

Kang, Woo Seok; Hur, Min; Lee, Jae-Ok; Song, Young-Hoon

2014-01-01

Graphical abstract: - Highlights: • Controlling hydrophilicity of polymer film by varying gas flow rate is proposed in atmospheric-pressure homogeneous plasma treatment. • Without employing additional reactive gas, requiring more plasma power and longer treatment time, hydrophilicity of polyimide films was improved after the low-gas-flow plasma treatment. • The gas flow rate affects the hydrophilic properties of polymer surface by changing the discharge atmosphere in the particular geometry of the reactor developed. • Low-gas-flow induced wettability control suggests effective and economical plasma treatment. - Abstract: This paper reports on controlling the hydrophilicity of polyimide films using atmospheric-pressure homogeneous plasmas by changing only the gas flow rate. The gas flow changed the discharge atmosphere by mixing the feed gas with ambient air because of the particular geometry of the reactor developed for the study, and a low gas flow rate was found to be favorable because it generated abundant nitrogen or oxygen species that served as sources of hydrophilic functional groups over the polymer surface. After low-gas-flow plasma treatment, the polymer surface exhibited hydrophilic characteristics with increased surface roughness and enhanced chemical properties owing to the surface addition of functional groups. Without adding any reactive gases or requiring high plasma power and longer treatment time, the developed reactor with low-gas-flow operation offered effective and economical wettability control of polyimide films

Yield of H2O2 in Gas-Liquid Phase with Pulsed DBD

Science.gov (United States)

Jiang, Song; Wen, Yiyong; Liu, Kefu

2014-01-01

Electric discharge in water can generate a large number of oxidants such as ozone, hydrogen peroxide and hydroxyl radicals. In this paper, a non-thermal plasma processing system was established by means of pulsed dielectric barrier discharge in gas-liquid phase. The electrodes of discharge reactor were staggered. The yield of H2O2 was enhanced after discharge. The effects of discharge time, discharge voltage, frequency, initial pH value, and feed gas were investigated. The concentration of hydrogen peroxide and ozone was measured after discharge. The experimental results were fully analyzed. The chemical reaction equations in water were given as much as possible. At last, the water containing Rhodamine B was tested in this system. The degradation rate came to 94.22% in 30 min.

Cold flame on Biofilm - Transport of Plasma Chemistry from Gas to Liquid Phase

Science.gov (United States)

Kong, Michael

2014-10-01

One of the most active and fastest growing fields in low-temperature plasma science today is biological effects of gas plasmas and their translation in many challenges of societal importance such as healthcare, environment, agriculture, and nanoscale fabrication and synthesis. Using medicine as an example, there are already three FDA-approved plasma-based surgical procedures for tissue ablation and blood coagulation and at least five phase-II clinical trials on plasma-assisted wound healing therapies. A key driver for realizing the immense application potential of near room-temperature ambient pressure gas plasmas, commonly known as cold atmospheric plasmas or CAP, is to build a sizeable interdisciplinary knowledge base with which to unravel, optimize, and indeed design how reactive plasma species interact with cells and their key components such as protein and DNA. Whilst a logical objective, it is a formidable challenge not least since existing knowledge of gas discharges is largely in the gas-phase and therefore not directly applicable to cell-containing matters that are covered by or embedded in liquid (e.g. biofluid). Here, we study plasma inactivation of biofilms, a jelly-like structure that bacteria use to protect themselves and a major source of antimicrobial resistance. As 60--90% of biofilm is made of water, we develop a holistic model incorporating physics and chemistry in the upstream CAP-generating region, a plasma-exit region as a buffer for as-phase transport, and a downstream liquid region bordering the gas buffer region. A special model is developed to account for rapid chemical reactions accompanied the transport of gas-phase plasma species through the gas-liquid interface and for liquid-phase chemical reactions. Numerical simulation is used to illustrate how key reactive oxygen species (ROS) are transported into the liquid, and this is supported with experimental data of both biofilm inactivation using plasmas and electron spin spectroscopy (ESR

Modeling of noble gas injection into tokamak plasmas

International Nuclear Information System (INIS)

Morozov, D.Kh.; Yurchenko, E.I.; Lukash, V.E.; Baronova, E.O.; Rozhansky, V.A.; Senichenkov, I.Yu.; Veselova, I.Yu.; Schneider, R.

2005-01-01

Noble gas injection for mitigation of the disruption in DIII-D is simulated. The simulation of the first two stages is performed: of the neutral gas jet penetration through the background plasmas, and of the thermal quench. In order to simulate the first stage the 1.5-dimensional numerical code LLP with improved radiation model for noble gas is used. It is demonstrated that the jet remains mainly neutral and thus is able to penetrate to the central region of the tokamak in accordance with experimental observations. Plasma cooling at this stage is provided by the energy exchange with the jet. The radiation is relatively small, and the plasma thermal energy is spent mainly on the jet expansion. The magnetic surfaces in contact with the jet are cooled significantly. The cooling front propagates towards the plasma center. The simulations of the plasma column dynamics in the presence of moving jet is performed by means of the free boundary transport modeling DINA code. It has been shown that the cooling front is accompanied by strongly localized 'shark fin-like' perturbation in toroidal current density profile. After few milliseconds the jet (together with the current perturbation) achieves the region where safety factor is slightly higher than unity and a new type of the non-local kink mode develops. The unstable kink perturbation is non-resonant for any magnetic surface, both inside the plasma column, and in the vacuum space. The mode disturbs mainly the core region. The growth time of the 'shark fin-like' mode is higher than the Alfven time by a factor of 100 for DIII-D parameters. Hence, the simulation describes the DIII-D experimental results, at least, qualitatively. (author)

Discharge characteristics and hydrodynamics behaviors of atmospheric plasma jets produced in various gas flow patterns

Science.gov (United States)

Setsuhara, Yuichi; Uchida, Giichiro; Nakajima, Atsushi; Takenaka, Kosuke; Koga, Kazunori; Shiratani, Masaharu

2015-09-01

Atmospheric nonequilibrium plasma jets have been widely employed in biomedical applications. For biomedical applications, it is an important issue to understand the complicated mechanism of interaction of the plasma jet with liquid. In this study, we present analysis of the discharge characteristics of a plasma jet impinging onto the liquid surface under various gas flow patterns such as laminar and turbulence flows. For this purpose, we analyzed gas flow patters by using a Schlieren gas-flow imaging system in detail The plasma jet impinging into the liquid surface expands along the liquid surface. The diameter of the expanded plasma increases with gas flow rate, which is well explained by an increase in the diameter of the laminar gas-flow channel. When the gas flow rate is further increased, the gas flow mode transits from laminar to turbulence in the gas flow channel, which leads to the shortening of the plasm-jet length. Our experiment demonstrated that the gas flow patterns strongly affect the discharge characteristics in the plasma-jet system. This study was partly supported by a Grant-in-Aid for Scientific Research on Innovative Areas ``Plasma Medical Innovation'' (24108003) from the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT).

Plasma Spraying of Copper by Hybrid Water-Gas DC Arc Plasma Torch

Czech Academy of Sciences Publication Activity Database

Kavka, Tetyana; Matějíček, Jiří; Ctibor, Pavel; Mašláni, Alan; Hrabovský, Milan

2011-01-01

Roč. 20, č. 4 (2011), s. 760-774 ISSN 1059-9630 R&D Projects: GA ČR GAP205/11/2070 Institutional research plan: CEZ:AV0Z20430508 Keywords : copper coatings * hybrid water-gas torch * metallic particle oxidation Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.812, year: 2011 http://www.springerlink.com/content/78n3736855261197/fulltext.pdf

Recombining processes in a cooling plasma by mixing of initially heated gas

International Nuclear Information System (INIS)

Furukane, Utaro; Sato, Kuninori; Takiyama, Ken; Oda, Toshiatsu.

1992-03-01

A numerical investigation of recombining process in a high temperature plasma in a quasi-steady state is made in a gas contact cooling, in which the initial temperature effect of contact gas heated up by the hot plasma is considered as well as the gas cooling due to the surrounding neutral particles freely coming into the plasma. The calculation has shown that the electron temperature relaxes in accord with experimental results and that the occurrence of recombining region and the inverted populations almost agree with the experimental ones. (author)

'' Ideal Gas '' gluon plasma with medium dependent dispersion relation

International Nuclear Information System (INIS)

Gorenstein, M.I.

1995-01-01

An '' ideal gas '' model with temperature dependent particle mass is constructed for the gluon plasma equation of state. This simple model gives us an example of a system with temperature dependent effective Hamiltonian. To satisfy thermodynamical relations in these systems, standard statistical mechanics formulas have to be supplemented by special requirements which are considered in details. A self-consistent '' ideal gas '' formulation is used to describe Monte Carlo lattice data for the thermodynamical functions of SU(2) and SU(3) gluon plasma. 14 refs., 8 figs

Plasma target output from a magnetically augmented, gas-injected, washer-stack plasma gun

International Nuclear Information System (INIS)

Osher, J.E.

1982-01-01

This article describes a new washer-stack gun design developed for the application of plasma target production for the startup of neutral-beam trapping in a fusion research magnetic confinement system. The gun is a Mo anode type that is D 2 injected and has an auxiliary pulsed magnet for control of plasma-flux mapping. One of the principal features of 2--10-ms duration pulses for gun operation in a suitable magnetic field is the formation of an arc column along magnetic field lines from the gun's central cathode electrode to the vacuum chamber walls (at common anode potential). The primary power output from a 5.0-cm-i.d. gun is typically carried along this arc column by a stream of approximately 2000 A of 50--250-eV electrons. This primary stream of relatively low-density energetic electrons efficiently ionizes the injected gas, forming a quasi-dc source of denser secondary plasma of approx.10 13 /cm 3 at a few eV, which is able to flow or diffuse away along a somewhat larger column of magnetic field lines. In plasma-target production tests on a test stand, a gun operated at a D 2 gas flow of 22 Torr ls -1 yielded 250 A of equivalent plasma flow

Propagation of atmospheric pressure helium plasma jet into ambient air at laminar gas flow

International Nuclear Information System (INIS)

Pinchuk, M; Kurakina, N; Spodobin, V; Stepanova, O

2017-01-01

The formation of an atmospheric pressure plasma jet (APPJ) in a gas flow passing through the discharge gap depends on both gas-dynamic properties and electrophysical parameters of the plasma jet generator. The paper presents the results of experimental and numerical study of the propagation of the APPJ in a laminar flow of helium. A dielectric-barrier discharge (DBD) generated inside a quartz tube equipped with a coaxial electrode system, which provided gas passing through it, served as a plasma source. The transition of the laminar regime of gas flow into turbulent one was controlled by the photography of a formed plasma jet. The corresponding gas outlet velocity and Reynolds numbers were revealed experimentally and were used to simulate gas dynamics with OpenFOAM software. The data of the numerical simulation suggest that the length of plasma jet at the unvarying electrophysical parameters of DBD strongly depends on the mole fraction of ambient air in a helium flow, which is established along the direction of gas flow. (paper)

Transient effects caused by pulsed gas and liquid injections into low pressure plasmas

International Nuclear Information System (INIS)

Ogawa, D; Goeckner, M; Overzet, L; Chung, C W

2010-01-01

The fast injection of liquid droplets into a glow discharge causes significant time variations in the pressure, the chemical composition of the gas and the phases present (liquid and/or solid along with gas). While the variations can be large and important, very few studies, especially kinetic studies, have been published. In this paper we examine the changes brought about in argon plasma by injecting Ar (gas), N 2 (gas) hexane (gas) and hexane (liquid droplets). The changes in the RF capacitively coupled power (forward and reflected), electron and ion density (n e , n i ), electron temperature (T e ) and optical emissions were monitored during the injections. It was found that the Ar injection (pressure change only) caused expected variations. The electron temperature reduced, the plasma density increased and the optical emission intensity remained nearly constant. The N 2 and hexane gas injections (chemical composition and pressure changes) also followed expected trends. The plasma densities increased and electron temperature decreased while the optical emissions changed from argon to the injected gas. These all serve to highlight the fact that the injection of evaporating hexane droplets in the plasma caused very little change. This is because the number of injected droplets is too small to noticeably affect the plasma, even though the shift in the chemical composition of the gas caused by evaporation from those same droplets can be very significant. The net conclusion is that using liquid droplets to inject precursors for low pressure plasmas is both feasible and controllable.

Gas flow dependence for plasma-needle disinfection of S. mutans bacteria

International Nuclear Information System (INIS)

Goree, J; Liu Bin; Drake, David

2006-01-01

The role of gas flow and transport mechanisms are studied for a small low-power impinging jet of weakly-ionized helium at atmospheric pressure. This plasma needle produces a non-thermal glow discharge plasma that kills bacteria. A culture of Streptococcus mutans (S. mutans) was plated onto the surface of agar, and spots on this surface were then treated with plasma. Afterwards, the sample was incubated and then imaged. These images, which serve as a biological diagnostic for characterizing the plasma, show a distinctive spatial pattern for killing that depends on the gas flow rate. As the flow is increased, the killing pattern varies from a solid circle to a ring. Images of the glow reveal that the spatial distribution of energetic electrons corresponds to the observed killing pattern. This suggests that a bactericidal species is generated in the gas phase by energetic electrons less than a millimetre from the sample surface. Mixing of air into the helium plasma is required to generate the observed O and OH radicals in the flowing plasma. Hydrodynamic processes involved in this mixing are buoyancy, diffusion and turbulence

Gas flow dependence for plasma-needle disinfection of S. mutans bacteria

Energy Technology Data Exchange (ETDEWEB)

Goree, J [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Liu Bin [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Drake, David [Dows Institute for Dental Research, Dept. of Endodontics, College of Dentistry, University of Iowa, Iowa City, IA 52242 (United States)

2006-08-21

The role of gas flow and transport mechanisms are studied for a small low-power impinging jet of weakly-ionized helium at atmospheric pressure. This plasma needle produces a non-thermal glow discharge plasma that kills bacteria. A culture of Streptococcus mutans (S. mutans) was plated onto the surface of agar, and spots on this surface were then treated with plasma. Afterwards, the sample was incubated and then imaged. These images, which serve as a biological diagnostic for characterizing the plasma, show a distinctive spatial pattern for killing that depends on the gas flow rate. As the flow is increased, the killing pattern varies from a solid circle to a ring. Images of the glow reveal that the spatial distribution of energetic electrons corresponds to the observed killing pattern. This suggests that a bactericidal species is generated in the gas phase by energetic electrons less than a millimetre from the sample surface. Mixing of air into the helium plasma is required to generate the observed O and OH radicals in the flowing plasma. Hydrodynamic processes involved in this mixing are buoyancy, diffusion and turbulence.

Electro-acoustic coupling in a plasma gas

OpenAIRE

Sutton, Yvonne

2011-01-01

Sound emission using an ionised medium has been the subject of research since the beginning of the 20th century. The mechanism involves modulation at an audio frequency of an electrically sustained plasma discharge. In a similar effect to lightning, the charged particles in the plasma respond to the varying energy input. With this comes gas heating, molecular excitation, light emission from relaxation of excited molecular states and acoustic emission resulting from thermal expansion within, a...

The response of the Tore Supra edge plasma to supersonic pulsed gas injection

Czech Academy of Sciences Publication Activity Database

Pánek, Radomír; Gunn, J. P.; Bucalossi, J.; Ďuran, Ivan; Geraud, A.; Hron, Martin; Loarer, T.; Pégourié, B.; Stöckel, Jan; Tsitrone, E.

337-339, č. 16 (2005), s. 530-534 ISSN 0022-3115. [Plasma Surface Interactions /16./. Portland, 24.5.2005-28.5.2005] R&D Projects: GA ČR(CZ) GP202/03/P062 Institutional research plan: CEZ:AV0Z20430508 Keywords : Edge plasma * Gas injection and fuelling * probes * Plasma flow * Tore Supra Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.414, year: 2005

Influence of surrounding gas, composition and pressure on plasma plume dynamics of nanosecond pulsed laser-induced aluminum plasmas

Directory of Open Access Journals (Sweden)

Mahmoud S. Dawood

2015-10-01

Full Text Available In this article, we present a comprehensive study of the plume dynamics of plasmas generated by laser ablation of an aluminum target. The effect of both ambient gas composition (helium, nitrogen or argon and pressure (from ∼5 × 10−7 Torr up to atmosphere is studied. The time- and space- resolved observation of the plasma plume are performed from spectrally integrated images using an intensified Charge Coupled Device (iCCD camera. The iCCD images show that the ambient gas does not significantly influence the plume as long as the gas pressure is lower than 20 Torr and the time delay below 300 ns. However, for pressures higher than 20 Torr, the effect of the ambient gas becomes important, the shortest plasma plume length being observed when the gas mass species is highest. On the other hand, space- and time- resolved emission spectroscopy of aluminum ions at λ = 281.6 nm are used to determine the Time-Of-Flight (TOF profiles. The effect of the ambient gas on the TOF profiles and therefore on the propagation velocity of Al ions is discussed. A correlation between the plasma plume expansion velocity deduced from the iCCD images and that estimated from the TOF profiles is presented. The observed differences are attributed mainly to the different physical mechanisms governing the two diagnostic techniques.

Static gas-liquid interfacial direct current discharge plasmas using ionic liquid cathode

International Nuclear Information System (INIS)

Kaneko, T.; Baba, K.; Hatakeyama, R.

2009-01-01

Due to the unique properties of ionic liquids such as their extremely low vapor pressure and high heat capacity, we have succeeded in creating the static and stable gas (plasmas)-liquid (ionic liquids) interfacial field using a direct current discharge under a low gas pressure condition. It is clarified that the ionic liquid works as a nonmetal liquid electrode, and furthermore, a secondary electron emission coefficient of the ionic liquid is larger than that of conventional metal electrodes. The plasma potential structure of the gas-liquid interfacial region, and resultant interactions between the plasma and the ionic liquid are revealed by changing a polarity of the electrode in the ionic liquid. By utilizing the ionic liquid as a cathode electrode, the positive ions in the plasma region are found to be irradiated to the ionic liquid. This ion irradiation causes physical and chemical reactions at the gas-liquid interfacial region without the vaporization of the ionic liquid.

Two-stage plasma gun based on a gas discharge with a self-heating hollow emitter.

Science.gov (United States)

Vizir, A V; Tyunkov, A V; Shandrikov, M V; Oks, E M

2010-02-01

The paper presents the results of tests of a new compact two-stage bulk gas plasma gun. The plasma gun is based on a nonself-sustained gas discharge with an electron emitter based on a discharge with a self-heating hollow cathode. The operating characteristics of the plasma gun are investigated. The discharge system makes it possible to produce uniform and stable gas plasma in the dc mode with a plasma density up to 3x10(9) cm(-3) at an operating gas pressure in the vacuum chamber of less than 2x10(-2) Pa. The device features high power efficiency, design simplicity, and compactness.

Two-stage plasma gun based on a gas discharge with a self-heating hollow emitter

International Nuclear Information System (INIS)

Vizir, A. V.; Tyunkov, A. V.; Shandrikov, M. V.; Oks, E. M.

2010-01-01

The paper presents the results of tests of a new compact two-stage bulk gas plasma gun. The plasma gun is based on a nonself-sustained gas discharge with an electron emitter based on a discharge with a self-heating hollow cathode. The operating characteristics of the plasma gun are investigated. The discharge system makes it possible to produce uniform and stable gas plasma in the dc mode with a plasma density up to 3x10 9 cm -3 at an operating gas pressure in the vacuum chamber of less than 2x10 -2 Pa. The device features high power efficiency, design simplicity, and compactness.

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

Treatment of Dye Wastewater by Using a Hybrid Gas/Liquid Pulsed Discharge Plasma Reactor

International Nuclear Information System (INIS)

Lu Na; Li Jie; Wu Yan; Masayuki, Sato

2012-01-01

A hybrid gas/liquid pulsed discharge plasma reactor using a porous ceramic tube is proposed for dye wastewater treatment. High voltage pulsed discharge plasma was generated in the gas phase and simultaneously the plasma channel was permeated through the tiny holes of the ceramic tube into the water phase accompanied by gas bubbles. The porous ceramic tube not only separated the gas phase and liquid phase but also offered an effective plasma spreading channel. The effects of the peak pulse voltage, additive gas varieties, gas bubbling rate, solution conductivity and TiO 2 addition were investigated. The results showed that this reactor was effective for dye wastewater treatment. The decoloration efficiency of Acid Orange II was enhanced with an increase in the power supplied. Under the studied conditions, 97% of Acid Orange II in aqueous solution was effectively decolored with additive oxygen gas, which was 51% higher than that with argon gas, and the increasing O 2 bubbling rate also benefited the decoloration of dye wastewater. Water conductivity had a small effect on the level of decoloration. Catalysis of TiO 2 could be induced by the pulsed discharge plasma and addition of TiO 2 aided the decoloration of Acid Orange II.

Dynamic gas flow during plasma operation in TMX-U

International Nuclear Information System (INIS)

Pickles, W.L.; Carter, M.R.; Clower, C.A.; Drake, R.P.; Hunt, A.L.; Simonen, T.C.; Turner, W.C.

1982-01-01

Control of the neutral density outside of the plasma radius is essential for proper operation of the various plasma configurations in TMX-U. TMX-U excess-beam, stream-gun, gas-box, and beam-reflux gases are pumped internally in regions defined by 73 0 Ti-gettered liners and warm Ti-gettered plasma liners. The array of fast and slow ion gauges - a large TMX-U diagnostic - has been used to measure the dynamic pressure in many of the liner-defined regions on three time scales. The natural divertor action, or plasma pump effect, of mirror plasmas has been measured using the ion gauge diagnostics on a fast time scale during operation of TMX-U with ECRH start-up. Routine operation of TMX-U is enhanced by the ability to verify the effectiveness of gettering and to locate leaks using pressure data collected on the two slow time scales. A computer code, DYNAVAC 6, which treats TMX-U as a set of conductance-coupled regions with pumping and sources in each region, has been used to successfully model the overall gas dynamics during all phases of TMX-U operation

Comprehensive metabolomics identified lipid peroxidation as a prominent feature in human plasma of patients with coronary heart diseases

Directory of Open Access Journals (Sweden)

Jianhong Lu

2017-08-01

Full Text Available Coronary heart disease (CHD is a complex human disease associated with inflammation and oxidative stress. The underlying mechanisms and diagnostic biomarkers for the different types of CHD remain poorly defined. Metabolomics has been increasingly recognized as an enabling technique with the potential to identify key metabolomic features in an attempt to understand the pathophysiology and differentiate different stages of CHD. We performed comprehensive metabolomic analysis in human plasma from 28 human subjects with stable angina (SA, myocardial infarction (MI, and healthy control (HC. Subsequent analysis demonstrated a uniquely altered metabolic profile in these CHD: a total of 18, 37 and 36 differential metabolites were identified to distinguish SA from HC, MI from SA, and MI from HC groups respectively. Among these metabolites, glycerophospholipid (GPL metabolism emerged as the most significantly disturbed pathway. Next, we used a targeted metabolomic approach to systematically analyze GPL, oxidized phospholipid (oxPL, and downstream metabolites derived from polyunsaturated fatty acids (PUFAs, such as arachidonic acid and linoleic acid. Surprisingly, lipids associated with lipid peroxidation (LPO pathways including oxidized PL and isoprostanes, isomers of prostaglandins, were significantly elevated in plasma of MI patients comparing to HC and SA, consistent with the notion that oxidative stress-induced LPO is a prominent feature in CHD. Our studies using the state-of-the-art metabolomics help to understand the underlying biological mechanisms involved in the pathogenesis of CHD; LPO metabolites may serve as potential biomarkers to differentiation MI from SA and HC. Keywords: Metabolomics, Lipid peroxidation, Lipidomics, Myocardial infarction, Isoprostanes, Coronary heart disease (CHD

An investigation of an underwater steam plasma discharge as alternative to air plasmas for water purification

International Nuclear Information System (INIS)

Gucker, Sarah N; Foster, John E; Garcia, Maria C

2015-01-01

An underwater steam plasma discharge, in which water itself is the ionizing media, is investigated as a means to introduce advanced oxidation species into contaminated water for the purpose of water purification. The steam discharge avoids the acidification observed with air discharges and also avoids the need for a feed gas, simplifying the system. Steam discharge operation did not result in a pH changes in the processing of water or simulated wastewater, with the actual pH remaining roughly constant during processing. Simulated wastewater has been shown to continue to decompose significantly after steam treatment, suggesting the presence of long-lived plasma produced radicals. During steam discharge operation, nitrate production is limited, and nitrite production was found to be below the detection threshold of (roughly 0.2 mg L −1 ). The discharge was operated over a broad range of deposited power levels, ranging from approximately 30 W to 300 W. Hydrogen peroxide production was found to scale with increasing power. Additionally, the hydrogen peroxide production efficiency of the discharge was found to be higher than many of the rates reported in the literature to date. (paper)

Electron density measurement in gas discharge plasmas by optical and acoustic methods

International Nuclear Information System (INIS)

Biagioni, A.; Anania, M.P.; Bellaveglia, M.; Chiadroni, E.; Giovenale, D. Di; Pirro, G. Di; Ferrario, M.; Pompili, R.; Shpakov, V.; Vaccarezza, C.; Villa, F.; Cianchi, A.; Filippi, F.; Mostacci, A.; Zigler, A.

2016-01-01

Plasma density represents a very important parameter for both laser wakefield and plasma wakefield acceleration, which use a gas-filled capillary plasma source. Several techniques can be used to measure the plasma density within a capillary discharge, which are mainly based on optical diagnostic methods, as for example the well-known spectroscopic method using the Stark broadening effect. In this work, we introduce a preliminary study on an alternative way to detect the plasma density, based on the shock waves produced by gas discharge in a capillary. Firstly, the measurements of the acoustic spectral content relative to the laser-induced plasmas by a solid target allowed us to understand the main properties of the acoustic waves produced during this kind of plasma generation; afterwards, we have extended such acoustic technique to the capillary plasma source in order to calibrate it by comparison with the stark broadening method.

Production of free radical by magnetized sheet plasma with vertical gas-flow

International Nuclear Information System (INIS)

Tonegawa, Akira; Takatori, Masahiko; Kawamura, Kazutaka

1995-01-01

Free radicals play an important role in plasma processing, environment problem, and space plasma and so on because of their outstanding physical properties. Although much work has been done on the free radicals in the reactive plasma, very little is known about the production mechanism of the free radicals against various plasma parameters. To overcome this problem, we have proposed to do a new system of a magnetized sheet plasma with vertical gas-flow. The sheet plasma is a special type of strongly magnetized highly ionized slab plasma. This system is controlled to the parameters of radicals and plasma independently. Therefore, it is possible to make a quantitative analysis of free radicals as the simple one. In this paper, we describe the magnetized sheet plasma with vertical gas-flow system and report the preliminary results of production of the free radical. In particular, we show to produce and control the OH free radical which has been the most commonly studied combustion species

Atomic and molecular hydrogen gas temperatures in a low-pressure helicon plasma

Science.gov (United States)

Samuell, Cameron M.; Corr, Cormac S.

2015-08-01

Neutral gas temperatures in hydrogen plasmas are important for experimental and modelling efforts in fusion technology, plasma processing, and surface modification applications. To provide values relevant to these application areas, neutral gas temperatures were measured in a low pressure (radiofrequency helicon discharge using spectroscopic techniques. The atomic and molecular species were not found to be in thermal equilibrium with the atomic temperature being mostly larger then the molecular temperature. In low power operation (measurements near a graphite target demonstrated localised cooling near the sample surface. The temporal evolution of the molecular gas temperature during a high power 1.1 ms plasma pulse was also investigated and found to vary considerably as a function of pressure.

Longitudinal gas-density profilometry for plasma-wakefield acceleration targets

Science.gov (United States)

Schaper, Lucas; Goldberg, Lars; Kleinwächter, Tobias; Schwinkendorf, Jan-Patrick; Osterhoff, Jens

2014-03-01

Precise tailoring of plasma-density profiles has been identified as one of the critical points in achieving stable and reproducible conditions in plasma wakefield accelerators. Here, the strict requirements of next generation plasma-wakefield concepts, such as hybrid-accelerators, with densities around 1017 cm-3 pose challenges to target fabrication as well as to their reliable diagnosis. To mitigate these issues we combine target simulation with fabrication and characterization. The resulting density profiles in capillaries with gas jet and multiple in- and outlets are simulated with the fluid code OpenFOAM. Satisfactory simulation results then are followed by fabrication of the desired target shapes with structures down to the 10 μm level. The detection of Raman scattered photons using lenses with large collection solid angle allows to measure the corresponding longitudinal density profiles at different number densities and allows a detection sensitivity down to the low 1017 cm-3 density range at high spatial resolution. This offers the possibility to gain insight into steep density gradients as for example in gas jets and at the plasma-to-vacuum transition.

Generation and confinement of microwave gas-plasma in photonic dielectric microstructure.

Science.gov (United States)

Debord, B; Jamier, R; Gérôme, F; Leroy, O; Boisse-Laporte, C; Leprince, P; Alves, L L; Benabid, F

2013-10-21

We report on a self-guided microwave surface-wave induced generation of ~60 μm diameter and 6 cm-long column of argon-plasma confined in the core of a hollow-core photonic crystal fiber. At gas pressure of 1 mbar, the micro-confined plasma exhibits a stable transverse profile with a maximum gas-temperature as high as 1300 ± 200 K, and a wall-temperature as low as 500 K, and an electron density level of 10¹⁴ cm⁻³. The fiber guided fluorescence emission presents strong Ar⁺ spectral lines in the visible and near UV. Theory shows that the observed combination of relatively low wall-temperature and high ionisation rate in this strongly confined configuration is due to an unprecedentedly wide electrostatic space-charge field and the subsequent ion acceleration dominance in the plasma-to-gas power transfer.

Circadian time structure of circulating plasma lipid peroxides, antioxidant enzymes and other small molecules in peptic ulcers.

Science.gov (United States)

Singh, Ranjana; Singh, Rajesh Kumar; Masood, Tariq; Tripathi, Anil Kumar; Mahdi, Abbas Ali; Singh, Raj Kumar; Schwartzkopff, Othild; Cornelissen, Germaine

2015-12-07

The circadian rhythm, as part of a broad time structure (chronome) of lipid peroxides and antioxidant defense mechanisms may relate to prevention, efficacy and management of preventive and curative chronotherapy. Fifty newly diagnosed patients with peptic ulcers, 30-45 years of age, and 60 age-matched clinically healthy volunteers were synchronized for one week with diurnal activity from about 06:00 to about 22:00 and nocturnal rest. Breakfast was served around 08:30, lunch around 13:30 and dinner around 20:30. Drugs known to affect the free-radical systems were not taken. Blood samples were collected at 6-hour intervals for 24h under standardized, presumably 24-hour synchronized conditions. Plasma lipid peroxides, in the form of malondialdehyde (MDA), blood superoxide dismutase (SOD), glutathione peroxide (GPx), glutathione reductase (GR), catalase (CAT) activities, and serum total protein, albumin, ascorbic acid, total serum cholesterol, and HDL-cholesterol concentrations were determined. By population-mean cosinor analysis, a marked circadian variation was demonstrated for all variables in healthy subjects and in ulcer patients (pascorbic acid, and HDL-C. They also had smaller circadian amplitude of SOD, CAT, GPx, GR, ascorbic acid, T-C, and HDL-C, but larger circadian amplitude of MDA and albumin. As compared to healthy subjects, the circadian acrophase of ulcer patients occurred later for MDA and GR and earlier for GPx. Mapping circadian rhythms, important chronome components that include trends with age and extra-circadian components characterizing antioxidants and pro-oxidants, is needed for exploring their putative role as markers in the treatment and management of peptic ulcers. Copyright © 2015. Published by Elsevier B.V.

[Changes of lipid peroxidation parameters in children being treated for cancer].

Science.gov (United States)

Kazanova, G V; Baĭkova, V N; Dumbraĭs, K O; Gracheva, I V; Durnov, L A; Gorozhanskaia, E G; Zakharova, N V; Kurmashov, V I; Belkina, B M

1997-01-01

Lipid peroxidation (LP) occurring in pediatric cancer patients receiving polychemotherapy has been investigated. Plasma level of malonic dialdehyde in children with retinoblastoma (Rtb) was found to drop while it remained unchanged in patients with acute lymphoblastic leukemia (ALL). The treatment caused different changes in the red cell catalase levels in said groups: the enzyme concentration increased in the Rtb patients in the course of therapy and decreased in the ALL group. A slight decline in alpha-tocopherol and retinol levels the Rtb group was matched by a relevant rise in blood-plasma in the ALL group. To adjust LP regulation and improve resistance, antioxidants should be given to pediatric cancer patients suffering peroxidation-related stress.

Effects of Dietary Lycopene Supplementation on Plasma Lipid Profile, Lipid Peroxidation and Antioxidant Defense System in Feedlot Bamei Lamb.

Science.gov (United States)

Jiang, Hongqin; Wang, Zhenzhen; Ma, Yong; Qu, Yanghua; Lu, Xiaonan; Luo, Hailing

2015-07-01

Lycopene, a red non-provitamin A carotenoid, mainly presenting in tomato and tomato byproducts, has the highest antioxidant activity among carotenoids because of its high number of conjugated double bonds. The objective of this study was to investigate the effect of lycopene supplementation in the diet on plasma lipid profile, lipid peroxidation and antioxidant defense system in feedlot lamb. Twenty-eight Bamei male lambs (90 days old) were divided into four groups and fed a basal diet (LP0, 40:60 roughage: concentrate) or the basal diet supplemented with 50, 100, and 200 mg/kg lycopene. After 120 days of feeding, all lambs were slaughtered and sampled. Dietary lycopene supplementation significantly reduced the levels of plasma total cholesterol (p0.05). The levels of TG (pCAT, pCAT (p<0.05, linearly) and SOD (p<0.001, linearly). Therefore, it was concluded that lycopene supplementation improved the antioxidant status of the lamb and optimized the plasma lipid profile, the dosage of 200 mg lycopene/kg feed might be desirable for growing lambs to prevent environment stress and maintain normal physiological metabolism.

Hydrogen peroxide plasma sterilization of a waterproof, high-definition video camera case for intraoperative imaging in veterinary surgery.

Science.gov (United States)

Adin, Christopher A; Royal, Kenneth D; Moore, Brandon; Jacob, Megan

2018-06-13

To evaluate the safety and usability of a wearable, waterproof high-definition camera/case for acquisition of surgical images by sterile personnel. An in vitro study to test the efficacy of biodecontamination of camera cases. Usability for intraoperative image acquisition was assessed in clinical procedures. Two waterproof GoPro Hero4 Silver camera cases were inoculated by immersion in media containing Staphylococcus pseudointermedius or Escherichia coli at ≥5.50E+07 colony forming units/mL. Cases were biodecontaminated by manual washing and hydrogen peroxide plasma sterilization. Cultures were obtained by swab and by immersion in enrichment broth before and after each contamination/decontamination cycle (n = 4). The cameras were then applied by a surgeon in clinical procedures by using either a headband or handheld mode and were assessed for usability according to 5 user characteristics. Cultures of all poststerilization swabs were negative. One of 8 cultures was positive in enrichment broth, consistent with a low level of contamination in 1 sample. Usability of the camera was considered poor in headband mode, with limited battery life, inability to control camera functions, and lack of zoom function affecting image quality. Handheld operation of the camera by the primary surgeon improved usability, allowing close-up still and video intraoperative image acquisition. Vaporized hydrogen peroxide sterilization of this camera case was considered effective for biodecontamination. Handheld operation improved usability for intraoperative image acquisition. Vaporized hydrogen peroxide sterilization and thorough manual washing of a waterproof camera may provide cost effective intraoperative image acquisition for documentation purposes. © 2018 The American College of Veterinary Surgeons.

Thermocatalytic Behavior of Manganese (IV Oxide as Nanoporous Material on the Dissociation of a Gas Mixture Containing Hydrogen Peroxide

Directory of Open Access Journals (Sweden)

Zaid B. Jildeh

2018-04-01

Full Text Available In this article, we present an overview on the thermocatalytic reaction of hydrogen peroxide (H 2 O 2 gas on a manganese (IV oxide (MnO 2 catalytic structure. The principle of operation and manufacturing techniques are introduced for a calorimetric H 2 O 2 gas sensor based on porous MnO 2 . Results from surface analyses by X-ray photoelectron spectroscopy (XPS and scanning electron microscopy (SEM of the catalytic material provide indication of the H 2 O 2 dissociation reaction schemes. The correlation between theory and the experiments is documented in numerical models of the catalytic reaction. The aim of the numerical models is to provide further information on the reaction kinetics and performance enhancement of the porous MnO 2 catalyst.

Thermocatalytic Behavior of Manganese (IV) Oxide as Nanoporous Material on the Dissociation of a Gas Mixture Containing Hydrogen Peroxide.

Science.gov (United States)

Jildeh, Zaid B; Oberländer, Jan; Kirchner, Patrick; Wagner, Patrick H; Schöning, Michael J

2018-04-21

In this article, we present an overview on the thermocatalytic reaction of hydrogen peroxide (H 2 O 2 ) gas on a manganese (IV) oxide (MnO 2 ) catalytic structure. The principle of operation and manufacturing techniques are introduced for a calorimetric H 2 O 2 gas sensor based on porous MnO 2 . Results from surface analyses by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) of the catalytic material provide indication of the H 2 O 2 dissociation reaction schemes. The correlation between theory and the experiments is documented in numerical models of the catalytic reaction. The aim of the numerical models is to provide further information on the reaction kinetics and performance enhancement of the porous MnO 2 catalyst.

Second derivative Langmuir probe diagnostics of gas discharge plasma at intermediate pressures (review article)

International Nuclear Information System (INIS)

Popov, Tsv K; Dimitrova, M; Dias, F M; Tsaneva, V N; Stelmashenko, N A; Blamire, M G; Barber, Z H

2006-01-01

The second-derivative Langmuir probe method for precise determination of the plasma potential, the electron energy distribution function (respectively the electron temperature,) and the electron density of gas discharge plasma at intermediate pressures (100-1000 Pa) is reviewed. Results of applying the procedure proposed to different kinds of gas discharges are presented. Factors affecting the accuracy of the plasma characteristics evaluated are discussed

Estimation of Flow Channel Parameters for Flowing Gas Mixed with Air in Atmospheric-pressure Plasma Jets

Science.gov (United States)

Yambe, Kiyoyuki; Saito, Hidetoshi

2017-12-01

When the working gas of an atmospheric-pressure non-equilibrium (cold) plasma flows into free space, the diameter of the resulting flow channel changes continuously. The shape of the channel is observed through the light emitted by the working gas of the atmospheric-pressure plasma. When the plasma jet forms a conical shape, the diameter of the cylindrical shape, which approximates the conical shape, defines the diameter of the flow channel. When the working gas flows into the atmosphere from the inside of a quartz tube, the gas mixes with air. The molar ratio of the working gas and air is estimated from the corresponding volume ratio through the relationship between the diameter of the cylindrical plasma channel and the inner diameter of the quartz tube. The Reynolds number is calculated from the kinematic viscosity of the mixed gas and the molar ratio. The gas flow rates for the upper limit of laminar flow and the lower limit of turbulent flow are determined by the corresponding Reynolds numbers estimated from the molar ratio. It is confirmed that the plasma jet length and the internal plasma length associated with strong light emission increase with the increasing gas flow rate until the rate for the upper limit of laminar flow and the lower limit of turbulent flow, respectively. Thus, we are able to explain the increasing trend in the plasma lengths with the diameter of the flow channel and the molar ratio by using the cylindrical approximation.

Calculation of gas-flow in plasma reactor for carbon partial oxidation

Science.gov (United States)

Bespala, Evgeny; Myshkin, Vyacheslav; Novoselov, Ivan; Pavliuk, Alexander; Makarevich, Semen; Bespala, Yuliya

2018-03-01

The paper discusses isotopic effects at carbon oxidation in low temperature non-equilibrium plasma at constant magnetic field. There is described routine of experiment and defined optimal parameters ensuring maximum enrichment factor at given electrophysical, gas-dynamic, and thermodymanical parameters. It has been demonstrated that at high-frequency generator capacity of 4 kW, supply frequency of 27 MHz and field density of 44 mT the concentration of paramagnetic heavy nuclei 13C in gaseous phase increases up to 1.78 % compared to 1.11 % for natural concentration. Authors explain isotopic effect decrease during plasmachemical separation induced by mixing gas flows enriched in different isotopes at the lack of product quench. With the help of modeling the motion of gas flows inside the plasma-chemical reactor based on numerical calculation of Navier-Stokes equation authors determine zones of gas mixing and cooling speed. To increase isotopic effects and proportion of 13C in gaseous phase it has been proposed to use quench in the form of Laval nozzle of refractory steel. The article represents results on calculation of optimal Laval Nozzle parameters for plasma-chemical reactor of chosen geometry of. There are also given dependences of quench time of products on pressure at the diffuser output and on critical section diameter. Authors determine the location of quench inside the plasma-chemical reactor in the paper.

Longitudinal gas-density profilometry for plasma-wakefield acceleration targets

Energy Technology Data Exchange (ETDEWEB)

Schaper, Lucas, E-mail: lschaper01@qub.ac.uk [Universität Hamburg, FB Physik, Institut für Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg (Germany); Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg (Germany); Goldberg, Lars; Kleinwächter, Tobias; Schwinkendorf, Jan-Patrick; Osterhoff, Jens [Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg (Germany)

2014-03-11

Precise tailoring of plasma-density profiles has been identified as one of the critical points in achieving stable and reproducible conditions in plasma wakefield accelerators. Here, the strict requirements of next generation plasma-wakefield concepts, such as hybrid-accelerators, with densities around 10{sup 17} cm{sup −3} pose challenges to target fabrication as well as to their reliable diagnosis. To mitigate these issues we combine target simulation with fabrication and characterization. The resulting density profiles in capillaries with gas jet and multiple in- and outlets are simulated with the fluid code OpenFOAM. Satisfactory simulation results then are followed by fabrication of the desired target shapes with structures down to the 10 µm level. The detection of Raman scattered photons using lenses with large collection solid angle allows to measure the corresponding longitudinal density profiles at different number densities and allows a detection sensitivity down to the low 10{sup 17} cm{sup −3} density range at high spatial resolution. This offers the possibility to gain insight into steep density gradients as for example in gas jets and at the plasma-to-vacuum transition.

A supersonic gas target for a bundle divertor plasma

International Nuclear Information System (INIS)

Chang, F.R.; Fisher, J.L.

1982-01-01

A novel gas target concept for recovering both energy and particles from a high-energy plasma stream is presented. This concept includes the maintenance of a pressure discontinuity by a normal shock and a very high mass flow rate in a relatively small system. The pressure discontinuity allows the exhaust plasma stream to minimize backflow into the plasma, by interacting with the target in a low-pressure region; the high mass flow rate allows exit temperatures that are reasonable from a materials viewpoint and suitable for energy recovery. (author)

Reactive radical-driven bacterial inactivation by hydrogen-peroxide-enhanced plasma-activated-water

Science.gov (United States)

Wu, Songjie; Zhang, Qian; Ma, Ruonan; Yu, Shuang; Wang, Kaile; Zhang, Jue; Fang, Jing

2017-08-01

The combined effects of plasma activated water (PAW) and hydrogen peroxide (H2O2), PAW/HP, in sterilization were investigated in this study. To assess the synergistic effects of PAW/HP, S. aureus was selected as the test microorganism to determine the inactivation efficacy. Also, the DNA/RNA and proteins released by the bacterial suspensions under different conditions were examined to confirm membrane integrity. Additionally, the intracellular pH (pHi) of S. aureus was measured in our study. Electron spin resonance spectroscopy (ESR) was employed to identify the presence of radicals. Finally, the oxidation reduction potential (ORP), conductivity and pH were measured. Our results revealed that the inactivation efficacy of PAW/HP is much greater than that of PAW, while increased H2O2 concentration result in higher inactivation potential. More importantly, as compared with PAW, the much stronger intensity ESR signals and higher ORP in PAW/HP suggests that the inactivation mechanism of the synergistic effects of PAW/HP: more reactive oxygen species (ROS) and reactive nitrogen species (RNS), especially OH and NO radicals, are generated in PAW combined with H2O2 resulting in more deaths of the bacteria.

Emerging applications of low temperature gas plasmas in the food industry.

Science.gov (United States)

Shaw, Alex; Shama, Gilbert; Iza, Felipe

2015-06-16

The global burden of foodborne disease due to the presence of contaminating micro-organisms remains high, despite some notable examples of their successful reduction in some instances. Globally, the number of species of micro-organisms responsible for foodborne diseases has increased over the past decades and as a result of the continued centralization of the food processing industry, outbreaks now have far reaching consequences. Gas plasmas offer a broad range of microbicidal capabilities that could be exploited in the food industry and against which microbial resistance would be unlikely to occur. In addition to reducing the incidence of disease by acting on the micro-organisms responsible for food spoilage, gas plasmas could also play a role in increasing the shelf-life of perishable foods and thereby reduce food wastage with positive financial and environmental implications. Treatment need not be confined to the food itself but could include food processing equipment and also the environment in which commercial food processing occurs. Moreover, gas plasmas could also be used to bring about the degradation of undesirable chemical compounds, such as allergens, toxins, and pesticide residues, often encountered on foods and food-processing equipment. The literature on the application of gas plasmas to food treatment is beginning to reveal an appreciation that attention needs also to be paid to ensuring that the key quality attributes of foods are not significantly impaired as a result of treatment. A greater understanding of both the mechanisms by which micro-organisms and chemical compounds are inactivated, and of the plasma species responsible for this is forming. This is significant, as this knowledge can then be used to design plasma systems with tailored compositions that will achieve maximum efficacy. Better understanding of the underlying interactions will also enable the design and implementation of control strategies capable of minimizing variations in

Fullerene-rare gas mixed plasmas in an electron cyclotron resonance ion source

Energy Technology Data Exchange (ETDEWEB)

Asaji, T., E-mail: asaji@oshima-k.ac.jp; Ohba, T. [Oshima National College of Maritime Technology, 1091-1 Komatsu, Suo-oshima, Oshima, Yamaguchi 742-2193 (Japan); Uchida, T.; Yoshida, Y. [Bio-Nano Electronics Research Centre, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan); Minezaki, H.; Ishihara, S. [Graduate School of Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan); Racz, R.; Biri, S. [Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Bem Tér 18/c (Hungary); Muramatsu, M.; Kitagawa, A. [National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kato, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

2014-02-15

A synthesis technology of endohedral fullerenes such as Fe@C{sub 60} has developed with an electron cyclotron resonance (ECR) ion source. The production of N@C{sub 60} was reported. However, the yield was quite low, since most fullerene molecules were broken in the ECR plasma. We have adopted gas-mixing techniques in order to cool the plasma and then reduce fullerene dissociation. Mass spectra of ion beams extracted from fullerene-He, Ar or Xe mixed plasmas were observed with a Faraday cup. From the results, the He gas mixing technique is effective against fullerene destruction.

Enhancement of gas sensor response of nanocrystalline zinc oxide for ammonia by plasma treatment

International Nuclear Information System (INIS)

Hou, Yue; Jayatissa, Ahalapitiya H.

2014-01-01

The effect of oxygen plasma treatment on nanocrystalline ZnO thin film based gas sensor was investigated. ZnO thin films were synthesized on alkali-free glass substrates by a sol–gel process. ZnO thin films were treated with oxygen plasma to change the number of vacancies/defects in ZnO. The effect of oxygen plasma on the structural, electrical, optical and gas sensing properties was investigated as a function of plasma treatment time. The results suggest that the microstructure and the surface morphology can be tuned by oxygen plasma treatment. The optical transmission in the visible range varies after the oxygen plasma treatment. Moreover, it is found that the oxygen plasma has significant impact on the electrical properties of ZnO thin films indicating a variation of resistivity. The oxygen plasma treated ZnO thin film exhibits an enhanced sensing response towards NH 3 in comparison with that of the as-deposited ZnO sensor. When compared with the as-deposited ZnO film, the sensing response was improved by 50% for the optimum oxygen plasma treatment time of 8 min. The selectivity of 8 min plasma treated ZnO sensor was also examined for an important industrial gas mixture of H 2 , CH 4 and NH 3 .

Biological Effect of Gas Plasma Treatment on CO2 Gas Foaming/Salt Leaching Fabricated Porous Polycaprolactone Scaffolds in Bone Tissue Engineering

Directory of Open Access Journals (Sweden)

Tae-Yeong Bak

2014-01-01

Full Text Available Porous polycaprolactone (PCL scaffolds were fabricated by using the CO2 gas foaming/salt leaching process and then PCL scaffolds surface was treated by oxygen or nitrogen gas plasma in order to enhance the cell adhesion, spreading, and proliferation. The PCL and NaCl were mixed in the ratios of 3 : 1. The supercritical CO2 gas foaming process was carried out by solubilizing CO2 within samples at 50°C and 8 MPa for 6 hr and depressurization rate was 0.4 MPa/s. The oxygen or nitrogen plasma treated porous PCL scaffolds were prepared at discharge power 100 W and 10 mTorr for 60 s. The mean pore size of porous PCL scaffolds showed 427.89 μm. The gas plasma treated porous PCL scaffolds surface showed hydrophilic property and the enhanced adhesion and proliferation of MC3T3-E1 cells comparing to untreated porous PCL scaffolds. The PCL scaffolds produced from the gas foaming/salt leaching and plasma surface treatment are suitable for potential applications in bone tissue engineering.

Two dimensional radial gas flows in atmospheric pressure plasma-enhanced chemical vapor deposition

Science.gov (United States)

Kim, Gwihyun; Park, Seran; Shin, Hyunsu; Song, Seungho; Oh, Hoon-Jung; Ko, Dae Hong; Choi, Jung-Il; Baik, Seung Jae

2017-12-01

Atmospheric pressure (AP) operation of plasma-enhanced chemical vapor deposition (PECVD) is one of promising concepts for high quality and low cost processing. Atmospheric plasma discharge requires narrow gap configuration, which causes an inherent feature of AP PECVD. Two dimensional radial gas flows in AP PECVD induces radial variation of mass-transport and that of substrate temperature. The opposite trend of these variations would be the key consideration in the development of uniform deposition process. Another inherent feature of AP PECVD is confined plasma discharge, from which volume power density concept is derived as a key parameter for the control of deposition rate. We investigated deposition rate as a function of volume power density, gas flux, source gas partial pressure, hydrogen partial pressure, plasma source frequency, and substrate temperature; and derived a design guideline of deposition tool and process development in terms of deposition rate and uniformity.

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.

Pomegranate (Punicagranatum juice decreases lipid peroxidation, but has no effect on plasma advanced glycated end-products in adults with type 2 diabetes: a randomized double-blind clinical trial

Directory of Open Access Journals (Sweden)

Golbon Sohrab

2015-09-01

Full Text Available Introduction: Diabetes mellitus characterized by hyperglycemia could increase oxidative stress and formation of advanced glycated end-products (AGEs, which contribute to diabetic complications. The purpose of this study was to assess the effect of pomegranate juice (PJ containing natural antioxidant on lipid peroxidation and plasma AGEs in patients with type 2 diabetes (T2D. Materials and methods: In a randomized, double-blind, placebo-controlled trial, 44 patients (age range 56±6.8 years, T2D were randomly assigned to one of two groups: group A (PJ, n=22 and group B (Placebo, n=22. At the baseline and the end of 12-week intervention, biochemical markers including fasting plasma glucose, insulin, oxidative stress, and AGE markers including carboxy methyl lysine (CML and pentosidine were assayed. Results: At baseline, there were no significant differences in plasma total antioxidant capacity (TAC levels between the two groups, but malondialdehyde (MDA decreased levels were significantly different (P<0.001. After 12 weeks of intervention, TAC increased (P<0.05 and MDA decreased (P<0.01 in the PJ group when compared with the placebo group. However, no significant differences were observed in plasma concentration of CML and pentosidine between the two groups. Conclusions: The study showed that PJ decreases lipid peroxidation. Therefore, PJ consumption may delay onset of T2D complications related to oxidative stress.

Gas-filled targets for large scalelength plasma interaction experiments on Nova

International Nuclear Information System (INIS)

Powers, L.V.; Berger, R.L.; Munro, D.H.

1994-11-01

Stimulated Brillouin backscatter from large scale length gas-filled targets has been measured on Nova. These targets were designed to approximate conditions in indirect drive ignition target designs in underdense plasma electron density (n e ∼10 21 /cm 3 ), temperature (T e >3 keV), and gradient scale lengths (L n ∼ mm, L v >6 mm) as well as calculated gain for stimulated Brillouin scattering (SBS). The targets used in these experiments were gas-filled balloons with polyimide walls (gasbags) and gas-filled hohlraums. Detailed characterization using x-ray imaging and x-ray and optical spectroscopy verifies that the calculated plasma conditions are achieved. Time-resolved SBS backscatter from these targets is <3% for conditions similar to ignition target designs

Plasma wave detection in laser spectroscopy and gas chromatography

International Nuclear Information System (INIS)

Franzke, J.; Irmer, A. von; Veza, D.; Niemax, K.

1995-01-01

Frequency changes of plasma oscillations in low-pressure discharges are used for sensitive detection of atomic or molecular trace gases. Analyte selectivity can be either obtained by resonant laser excitation or by gas chromatography

Fundamental limits on gas-phase chemical reduction of NOx in a plasma

Energy Technology Data Exchange (ETDEWEB)

Penetrante, B.M.; Hsiao, M.C.; Merritt, B.T.; Vogtlin, G.E. [Lawrence Livermore National Lab., CA (United States)

1997-12-31

In the plasma, the electrons do not react directly with the NOx molecules. The electrons collide mainly with the background gas molecules like N{sub 2}, O{sub 2} and H{sub 2}O. Electron impact on these molecules result partly in dissociation reactions that produce reactive species like N, O and OH. The NOx in the engine exhaust gas initially consist mostly of NO. The ground state nitrogen atom, N, is the only species that could lead to the chemical reduction of NO to N{sub 2}. The O radical oxidizes NO to NO{sub 2} leaving the same amount of NOx. The OH radical converts NO{sub 2} to nitric acid. Acid products in the plasma can easily get adsorbed on surfaces in the plasma reactor and in the pipes. When undetected, the absence of these oxidation products can often be mistaken for chemical reduction of NOx. In this paper the authors will examine the gas-phase chemical reduction of NOx. They will show that under the best conditions, the plasma can chemically reduce 1.6 grams of NOx per brake-horsepower-hour [g(NOx)/bhp-hr] when 5% of the engine output energy is delivered to the plasma.

Clinical Symptoms in Fibromyalgia Are Better Associated to Lipid Peroxidation Levels in Blood Mononuclear Cells Rather than in Plasma

Science.gov (United States)

Cano-García, Francisco J.; De Miguel, Manuel; Carrión, Angel M.; Navas, Plácido; Sánchez Alcázar, José A.

2011-01-01

Background We examined lipid peroxidation (LPO) in blood mononuclear cells (BMCs) and plasma, as a marker of oxidative damage, and its association to clinical symptoms in Fibromyalgia (FM) patients. Methods We conducted a case–control and correlational study comparing 65 patients and 45 healthy controls. Clinical parameters were evaluated using the Fibromyalgia Impact Questionnaire (FIQ), visual analogues scales (VAS), and the Beck Depression Inventory (BDI). Oxidative stress was determined by measuring LPO in BMCs and plasma. Results We found increased LPO levels in BMCs and plasma from FM patients as compared to normal control (P<0.001). A significant correlation between LPO in BMCs and clinical parameters was observed (r = 0.584, P<0.001 for VAS; r = 0.823, P<0.001 for FIQ total score; and r = 0.875, P<0.01 for depression in the BDI). We also found a positive correlation between LPO in plasma and clinical symptoms (r = 0.452, P<0.001 for VAS; r = 0.578, P<0.001 for FIQ total score; and r = 0.579, P<0.001 for depression in the BDI). Partial correlation analysis controlling for age and BMI, and sex, showed that both LPO in cells and plasma were independently associated to clinical symptoms. However, LPO in cells, but not LPO in plasma, was independently associated to clinical symptoms when controlling for depression (BDI scores). Discussion The results of this study suggest a role for oxidative stress in the pathophysiology of fibromyalgia and that LPO in BMCs rather than LPO in plasma is better associated to clinical symptoms in FM. PMID:22046409

Clinical symptoms in fibromyalgia are better associated to lipid peroxidation levels in blood mononuclear cells rather than in plasma.

Directory of Open Access Journals (Sweden)

Mario D Cordero

Full Text Available BACKGROUND: We examined lipid peroxidation (LPO in blood mononuclear cells (BMCs and plasma, as a marker of oxidative damage, and its association to clinical symptoms in Fibromyalgia (FM patients. METHODS: We conducted a case-control and correlational study comparing 65 patients and 45 healthy controls. Clinical parameters were evaluated using the Fibromyalgia Impact Questionnaire (FIQ, visual analogues scales (VAS, and the Beck Depression Inventory (BDI. Oxidative stress was determined by measuring LPO in BMCs and plasma. RESULTS: We found increased LPO levels in BMCs and plasma from FM patients as compared to normal control (P<0.001. A significant correlation between LPO in BMCs and clinical parameters was observed (r = 0.584, P<0.001 for VAS; r = 0.823, P<0.001 for FIQ total score; and r = 0.875, P<0.01 for depression in the BDI. We also found a positive correlation between LPO in plasma and clinical symptoms (r = 0.452, P<0.001 for VAS; r = 0.578, P<0.001 for FIQ total score; and r = 0.579, P<0.001 for depression in the BDI. Partial correlation analysis controlling for age and BMI, and sex, showed that both LPO in cells and plasma were independently associated to clinical symptoms. However, LPO in cells, but not LPO in plasma, was independently associated to clinical symptoms when controlling for depression (BDI scores. DISCUSSION: The results of this study suggest a role for oxidative stress in the pathophysiology of fibromyalgia and that LPO in BMCs rather than LPO in plasma is better associated to clinical symptoms in FM.

Diffusion-controlled regime of surface-wave-produced plasmas in helium gas

International Nuclear Information System (INIS)

Berndt, J; Makasheva, K; Schlueter, H; Shivarova, A

2002-01-01

The study presents a numerical fluid-plasma model of diffusion-controlled surface-wave-sustained discharges in helium gas. The self-consistent behaviour of the discharge based on the interrelation between plasma density and Θ, the power absorbed on average by one electron, is described. The nonlinear process of step ionization in the charged particle balance equation is the main factor, which ensures the self-consistency. However, it is shown that in helium discharges, the ionization frequencies enter the dependence of Θ on the plasma density also through the ambipolar-diffusion coefficient. Results at two different values of the gas pressure and of the wave frequency are discussed. The lower value of the gas pressure is chosen according to the condition to have a pure diffusion-controlled regime without interference with a transition to the free-fall regime. The boundary condition for the ion flux at the wall sheath is used for determination of the value of μ, the quantity denoting the degree of the radial plasma-density inhomogeneity which, together with the electron-neutral elastic collision frequency, influences the wave propagation characteristics. The two values of the wave frequency chosen provide descriptions of high-frequency and microwave discharges. The model results in the self-consistent structure of the discharge: interrelated variations along the discharge length of wavenumber, space damping rate, Θ, plasma density and electron temperature. The power necessary for sustaining discharges of a given length is also calculated. Comparisons with argon discharges are shown

Three-dimensional modeling of the neutral gas depletion effect in a helicon discharge plasma

Science.gov (United States)

Kollasch, Jeffrey; Schmitz, Oliver; Norval, Ryan; Reiter, Detlev; Sovinec, Carl

2016-10-01

Helicon discharges provide an attractive radio-frequency driven regime for plasma, but neutral-particle dynamics present a challenge to extending performance. A neutral gas depletion effect occurs when neutrals in the plasma core are not replenished at a sufficient rate to sustain a higher plasma density. The Monte Carlo neutral particle tracking code EIRENE was setup for the MARIA helicon experiment at UW Madison to study its neutral particle dynamics. Prescribed plasma temperature and density profiles similar to those in the MARIA device are used in EIRENE to investigate the main causes of the neutral gas depletion effect. The most dominant plasma-neutral interactions are included so far, namely electron impact ionization of neutrals, charge exchange interactions of neutrals with plasma ions, and recycling at the wall. Parameter scans show how the neutral depletion effect depends on parameters such as Knudsen number, plasma density and temperature, and gas-surface interaction accommodation coefficients. Results are compared to similar analytic studies in the low Knudsen number limit. Plans to incorporate a similar Monte Carlo neutral model into a larger helicon modeling framework are discussed. This work is funded by the NSF CAREER Award PHY-1455210.

Purification of the gas after pyrolysis in coupled plasma-catalytic system

Directory of Open Access Journals (Sweden)

Młotek Michał

2017-12-01

Full Text Available Gliding discharge and coupled plasma-catalytic system were used for toluene conversion in a gas composition such as the one obtained during pyrolysis of biomass. The chosen catalyst was G-0117, which is an industrial catalyst for methane conversion manufactured by INS Pulawy (Poland. The effects of discharge power, initial concentration of toluene, gas flow rate and the presence of the bed of the G-0117 catalyst on the conversion of C7H8, a model tars compounds were investigated. Conversion of coluene increases with discharge power and the highest one was noted in the coupled plasma-catalytic system. It was higher than that in the homogeneous system of gliding discharge. When applying a reactor with reduced G-0117 and CO (0.15 mol%, CO2 (0.15 mol%, H2 (0.30 mol%, N2 (0.40 mol%, 4000 ppm of toluene and gas flow rate of 1.5 Nm3/h, the conversion of toluene was higher than 99%. In the coupled plasma-catalytic system with G-0117 methanation of carbon oxides was observed.

[Investigation on the gas temperature of a plasma jet at atmospheric pressure by emission spectrum].

Science.gov (United States)

Li, Xue-chen; Yuan, Ning; Jia, Peng-ying; Niu, Dong-ying

2010-11-01

A plasma jet of a dielectric barrier discharge in coaxial electrode was used to produce plasma plume in atmospheric pressure argon. Spatially and temporally resolved measurement was carried out by photomultiplier tubes. The light emission signals both from the dielectric barrier discharge and from the plasma plume were analyzed. Furthermore, emission spectrum from the plasma plume was collected by high-resolution optical spectrometer. The emission spectra of OH (A 2sigma + --> X2 II, 307.7-308.9 nm) and the first negative band of N2+ (B2 sigma u+ --> X2 IIg+, 390-391.6 nm) were used to estimate the rotational temperature of the plasma plume by fitting the experimental spectra to the simulated spectra. The rotational temperature obtained is about 443 K by fitting the emission spectrum from the OH, and that from the first negative band of N2+ is about 450 K. The rotational temperatures obtained by the two method are consistent within 5% error band. The gas temperature of the plasma plume at atmospheric pressure was obtained because rotational temperature equals to gas temperature approximately in gas discharge at atmospheric pressure. Results show that gas temperature increases with increasing the applied voltage.

Direct and controllable nitric oxide delivery into biological media and living cells by a pin-to-hole spark discharge (PHD) plasma

Energy Technology Data Exchange (ETDEWEB)

Dobrynin, D; Friedman, G [Electrical and Computer Engineering Department, College of Engineering, Drexel University, Philadelphia, PA (United States); Arjunan, K; Clyne, A Morss [School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA (United States); Fridman, A, E-mail: alisam@coe.drexel.edu [Department of Mechanical Engineering and Mechanics, College of Engineering, Drexel University, Philadelphia, PA (United States)

2011-02-23

Nitric oxide has great potential for improving wound healing through both inflammatory and vascularization processes. Nitric oxide can be produced in high concentrations by atmospheric pressure thermal plasmas. We measured the physical characteristics and nitric oxide production of a pin-to-hole spark discharge (PHD) plasma, as well as plasma-produced nitric oxide delivery into liquid and endothelial cells. The plasma temperature was calculated as 9030 {+-} 320 K by the Boltzmann method, which was adequate to produce nitric oxide, although the average gas temperature was near room temperature. The plasma produced significant UV radiation and hydrogen peroxide, but these were prevented from reaching the cells by adding a straight or curved tube extension to the plasma device. Plasma-produced nitric oxide in gas reached 2000 ppm and rapidly diffused into liquid and cells. Cells remained viable following plasma treatment and showed a linear increase in cGMP concentration with plasma treatment, indicating an intracellular functional response to PHD plasma NO. These data suggest that this plasma may provide a novel method for delivering NO locally and directly for enhanced wound healing.

Direct and controllable nitric oxide delivery into biological media and living cells by a pin-to-hole spark discharge (PHD) plasma

International Nuclear Information System (INIS)

Dobrynin, D; Friedman, G; Arjunan, K; Clyne, A Morss; Fridman, A

2011-01-01

Nitric oxide has great potential for improving wound healing through both inflammatory and vascularization processes. Nitric oxide can be produced in high concentrations by atmospheric pressure thermal plasmas. We measured the physical characteristics and nitric oxide production of a pin-to-hole spark discharge (PHD) plasma, as well as plasma-produced nitric oxide delivery into liquid and endothelial cells. The plasma temperature was calculated as 9030 ± 320 K by the Boltzmann method, which was adequate to produce nitric oxide, although the average gas temperature was near room temperature. The plasma produced significant UV radiation and hydrogen peroxide, but these were prevented from reaching the cells by adding a straight or curved tube extension to the plasma device. Plasma-produced nitric oxide in gas reached 2000 ppm and rapidly diffused into liquid and cells. Cells remained viable following plasma treatment and showed a linear increase in cGMP concentration with plasma treatment, indicating an intracellular functional response to PHD plasma NO. These data suggest that this plasma may provide a novel method for delivering NO locally and directly for enhanced wound healing.

Adaptive plasma for cancer therapy: physics, mechanism and applications

Science.gov (United States)

Keidar, Michael

2017-10-01

One of the most promising applications of cold atmospheric plasma (CAP) is the cancer therapy. The uniqueness of plasma is in its ability to change composition in situ. Plasma self-organization could lead to formation of coherent plasma structures. These coherent structures tend to modulate plasma chemistry and composition, including reactive species, the electric field and charged particles. Formation of coherent plasma structures allows the plasma to adapt to external boundary conditions, such as different cells types and their contextual tissues. In this talk we will explore possibilities and opportunities that the adaptive plasma therapeutic system might offer. We shall define such an adaptive system as a plasma device that is able to adjust the plasma composition to obtain optimal desirable outcomes through its interaction with cells and tissues. The efficacy of cold plasma in a pre-clinical model of various cancer types such as lung, bladder, breast, head, neck, brain and skin has been demonstrated. Both in-vitro and in-vivo studies revealed that cold plasmas selectively kill cancer cells. Recently mechanism of plasma selectivity based on aquaporin hypothesis has been proposed. Aquaporins (AQPs) are the confirmed membrane channels of H2O2 and other large molecules. We have demonstrated that the anti-cancer capacity of plasma could be inhibited by silencing the expression of AQPs. Additional possible cell feedback mechanism was recently discovered. It is associated with production of reactive species during direct CAP treatment by cancer cells. Selective production of hydrogen peroxide by different cells can lead to adaptation of chemistry at the plasma-cell interface based on the cellular input. In particular we have found that the discharge voltage is an important factor affecting the ratio of reactive oxygen species to reactive nitrogen species in the gas phase and this correlates well with effect of hydrogen peroxide production by cells. This work was

Analysis on discharge process of a plasma-jet triggered gas spark switch

Science.gov (United States)

Weihao, TIE; Cui, MENG; Yuting, ZHANG; Zirang, YAN; Qiaogen, ZHANG

2018-01-01

The plasma-jet triggered gas switch (PJTGS) could operate at a low working coefficient with a low jitter. We observed and analyzed the discharge process of the PJTGS at the lowest working coefficient of 47% with the trigger voltage of 40 kV and the pulse energy of 2 J to evaluate the effect of the plasma jet. The temporal and spatial evolution and the optical emission spectrum of the plasma jet were captured. And the spraying delay time and outlet velocity under different gas pressures were investigated. In addition, the particle in cell with Monte Carlo collision was employed to obtain the particle distribution of the plasma jet varying with time. The results show that, the plasma jet generated by spark discharge is sprayed into a spark gap within tens of nanoseconds, and its outlet velocity could reach 104 m s-1. The plasma jet plays a non-penetrating inducing role in the triggered discharge process of the PJTGS. On the one hand, the plasma jet provides the initial electrons needed by the discharge; on the other hand, a large number of electrons focusing on the head of the plasma jet distort the electric field between the head of the plasma jet and the opposite electrode. Therefore, a fast discharge originated from the plasma jet is induced and quickly bridges two electrodes.

Low-temperature plasma-catalytic oxidation of formaldehyde in atmospheric pressure gas streams

International Nuclear Information System (INIS)

Ding Huixian; Zhu Aimin; Lu Fugong; Xu Yong; Zhang Jing; Yang Xuefeng

2006-01-01

Formaldehyde (HCHO) is a typical air pollutant capable of causing serious health disorders in human beings. This work reports plasma-catalytic oxidation of formaldehyde in gas streams via dielectric barrier discharges over Ag/CeO 2 pellets at atmospheric pressure and 70 0 C. With a feed gas mixture of 276 ppm HCHO, 21.0% O 2 , 1.0% H 2 O in N 2 , ∼99% of formaldehyde can be effectively destructed with an 86% oxidative conversion into CO 2 at GHSV of 16500 h -1 and input discharge energy density of 108 J l -1 . At the same experimental conditions, the conversion percentages of HCHO to CO 2 from pure plasma-induced oxidation (discharges over fused silica pellets) and from pure catalytic oxidation over Ag/CeO 2 (without discharges) are 6% and 33% only. The above results and the CO plasma-catalytic oxidation experiments imply that the plasma-generated short-lived gas phase radicals, such as O and HO 2 , play important roles in the catalytic redox circles of Ag/CeO 2 to oxidize HCHO and CO to CO 2

Metallurgical response of an AISI 4140 steel to different plasma nitriding gas mixtures

Directory of Open Access Journals (Sweden)

Adão Felipe Oliveira Skonieski

2013-01-01

Full Text Available Plasma nitriding is a surface modification process that uses glow discharge to diffuse nitrogen atoms into the metallic matrix of different materials. Among the many possible parameters of the process, the gas mixture composition plays an important role, as it impacts directly the formed layer's microstructure. In this work an AISI 4140 steel was plasma nitrided under five different gas compositions. The plasma nitriding samples were characterized using optical and scanning electron microscopy, microhardness test, X-ray diffraction and GDOES. The results showed that there are significant microstructural and morphological differences on the formed layers depending on the quantity of nitrogen and methane added to the plasma nitriding atmosphere. Thicknesses of 10, 5 and 2.5 µm were obtained when the nitrogen content of the gas mixtures were varied. The possibility to obtain a compound layer formed mainly by γ'-Fe4N nitrides was also shown. For all studied plasma nitriding conditions, the presence of a compound layer was recognized as being the responsible to hinder the decarburization on the steel surface. The highest value of surface hardness - 1277HV - were measured in the sample which were nitrided with 3vol.% of CH4.

On the stability of localized drift modes in the boundary layers of high density gas insulated plasmas

International Nuclear Information System (INIS)

Ohlsson, D.

1977-11-01

Gas blanket systems are of interest for mainly two reasons. First, plasma wall interaction effects are expected to be considerably reduced due to the presence of the surrounding neutral gas. Consequently the impurity radiation due to impurities originating from plasma wall interaction processes is probably eliminated to a large extent. Second, the fueling of a future thermonuclear reactor can take place in a natural way in gas blanket systems in the sense that neutrals can diffuse inwards at a suitable rate to replace burnt fuel under certain conditions. In this analysis we consider certain stability aspects of plasmas surrounded by neutral gas. In particular we consider the stability of localized collisional drift modes, in the cool partially ionized boundary regions. In these regions large pressure gradients are expected due to plasma neutral gas interaction effects. It is concluded that stability is possible within certain parameter ranges due to the presence of several stabilizing effects associated with finite Larmor radius and viscosity effects and coupling between dissipative effects directly or indirectly connected with plasma neutral gas interaction processes

Integrated transport code system for a multicomponent plasma in a gas dynamic trap

International Nuclear Information System (INIS)

Anikeev, A.V.; Karpushov, A.N.; Noak, K.; Strogalova, S.L.

2000-01-01

This report is focused on the development of the theoretical and numerical models of multicomponent high-β plasma confinement and transport in the gas-dynamic trap (GDT). In order to simulate the plasma behavior in the GDT as well as that in the GDT-based neutron source the Integrated Transport Code System is developed from existing stand-alone codes calculating the target plasma, the fast ions and the neutral gas in the GDT. The code system considers the full dependence of the transport phenomena on space, time, energy and angle variables as well as the interactions between the particle fields [ru

A comparative study on two explosive acetone peroxides

Energy Technology Data Exchange (ETDEWEB)

Egorshev, V. Yu.; Sinditskii, V.P., E-mail: vps@rctu.ru; Smirnov, S.P.

2013-12-20

Highlights: • The most accurate heats of DADP and TATP sublimation were evaluated from experimental vapor pressures in a widened temperature range. • DADP is more volatile while more thermally stable peroxide than TATP. • DADP reveals lesser sensitivity to drop-weight impact, flame temperature, burning rate, and initiating efficiency as compared with TATP. - Abstract: Two explosive cyclic acetone peroxides, diacetone diperoxide (DADP) and triacetone triperoxide (TATP) have been studied in respect of thermal decomposition, burning behavior, impact sensitivity, and initiating efficiency. Using the glass Bourdon gauge technique, the vapor pressures of TATP and DADP were determined over the temperature range 75–144 °C and 67–120 °C, respectively. The kinetic parameters of decomposition of the peroxides in the gas phase have been obtained in the temperature interval of 140–200 °C. The decomposition of both DADP and TATP followed the first-order reaction to high degrees of decay with close activation energies of 159.2 kJ/mol (38.0 kcal/mol) and 165.8 kJ/mol (39.6 kcal/mol), respectively. The decomposition rate constants of DADP were found to be approximately 2 times less than those of TATP. The linear burning rate of DADP measured in a constant-pressure window bomb appeared to be approximately 5 times less than that of TATP. Temperature profiles in the combustion wave were measured at subatmospheric pressures with the help of thin tungsten-rhenium thermocouples. The leading reaction on combustion of both volatile peroxides was assumed to occur in the gas phase. Kinetic parameters of the leading reaction derived from the combustion data showed a good agreement with kinetic parameters of low-temperature thermal decomposition extrapolated to the high-temperature flame zone. In the drop-weight impact test, DADP appeared to be notably less sensitive peroxide than TATP. No deflagration-to-detonation transition was observed when RDX was attempted to explode by

Transition from gas to plasma kinetic equilibria in gravitating axisymmetric structures

International Nuclear Information System (INIS)

Cremaschini, Claudio; Stuchlík, Zdeněk

2014-01-01

The problem of the transition from gas to plasma in gravitating axisymmetric structures is addressed under the assumption of having initial and final states realized by kinetic Maxwellian-like equilibria. In astrophysics, the theory applies to accretion-disc scenarios around compact objects. A formulation based on non-relativistic kinetic theory for collisionless systems is adopted. Equilibrium solutions for the kinetic distribution functions describing the initial neutral matter and the resulting plasma state are constructed in terms of single-particle invariants and expressed by generalized Maxwellian distributions. The final plasma configuration is related to the initial gas distribution by the introduction of appropriate functional constraints. Qualitative aspects of the solution are investigated and physical properties of the system are pointed out. In particular, the admitted functional dependences of the fluid fields carried by the corresponding equilibrium distributions are determined. Then, the plasma is proved to violate the condition of quasi-neutrality, implying a net charge separation between ions and electrons. This result is shown to be independent of the precise realization of the plasma distribution function, while a physical mechanism able to support a non-neutral equilibrium state is proposed

Transition from gas to plasma kinetic equilibria in gravitating axisymmetric structures

Energy Technology Data Exchange (ETDEWEB)

Cremaschini, Claudio; Stuchlík, Zdeněk [Institute of Physics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo nám.13, CZ-74601 Opava (Czech Republic)

2014-04-15

The problem of the transition from gas to plasma in gravitating axisymmetric structures is addressed under the assumption of having initial and final states realized by kinetic Maxwellian-like equilibria. In astrophysics, the theory applies to accretion-disc scenarios around compact objects. A formulation based on non-relativistic kinetic theory for collisionless systems is adopted. Equilibrium solutions for the kinetic distribution functions describing the initial neutral matter and the resulting plasma state are constructed in terms of single-particle invariants and expressed by generalized Maxwellian distributions. The final plasma configuration is related to the initial gas distribution by the introduction of appropriate functional constraints. Qualitative aspects of the solution are investigated and physical properties of the system are pointed out. In particular, the admitted functional dependences of the fluid fields carried by the corresponding equilibrium distributions are determined. Then, the plasma is proved to violate the condition of quasi-neutrality, implying a net charge separation between ions and electrons. This result is shown to be independent of the precise realization of the plasma distribution function, while a physical mechanism able to support a non-neutral equilibrium state is proposed.

Effects of gas chamber geometry and gas flow on the neutron production in a fast plasma focus neutron source

International Nuclear Information System (INIS)

Tarifeño-Saldivia, Ariel; Soto, Leopoldo

2014-01-01

This work reports that gas chamber geometry and gas flow management substantially affect the neutron production of a repetitive fast plasma focus. The gas flow rate is the most sensitive parameter. An appropriate design of the gas chamber combined with a suitable flow-rate management can lead to improvements in the neutron production of one order of magnitude working in a fast repetitive mode. (paper)

Intense microwave pulse propagation through gas breakdown plasmas in a waveguide

International Nuclear Information System (INIS)

Byrne, D.P.

1986-01-01

High-power microwave pulse-compression techniques are used to generate 2.856 GHz pulses which are propagated in a TE 10 mode through a gas filled section of waveguide, where the pulses interact with self-generated gas-breakdown plasmas. Pulse envelopes transmitted through the plasmas, with duration varying from 2 ns to greater than 1 μs, and peak powers of a few kW to nearly 100 MW, are measured as a function of incident pulse and gas pressure for air, nitrogen, and helium. In addition, the spatial and temporal development of the optical radiation emitted by the breakdown plasmas are measured. For transmitted pulse durations ≥ 100 ns, good agreement is found with both theory and existing measurements. For transmitted pulse duration as short as 2 ns (less than 10 rf cycles), a two-dimensional model is used in which the electrons in the plasma are treated as a fluid whose interactions with the microwave pulse are governed by a self-consistent set of fluid equations and Maxwell's equations for the electromagnetic field. The predictions of this model for air are compared with the experimental results over a pressure range of 0.8 torr to 300 torr. Good agreement is obtained above about 1 torr pressure, demonstrating that microwave pulse propagation above the breakdown threshold can be accurately modeled on this time scale. 63 refs., 44 figs., 2 tabs

Mechanisms of disruptions caused by noble gas injection into tokamak plasmas

International Nuclear Information System (INIS)

Morozov, D.Kh.; Yurchenko, E.I.; Lukash, V.E.; Baronova, E.O.; Pozdnyakov, Yu.I.; Rozhansky, V.A.; Senichenkov, I.Yu.; Veselova, I.Yu.; Schneider, R.

2005-01-01

Noble gas injection for disruption mitigation in DIII-D is simulated. The simulation of the first two stages of the disruption is performed: the first one is the neutral gas jet penetration through the background plasmas, and the second one is the instability growth. In order to simulate the first stage, the MHD pellet code LLP with improved radiation model for noble gas is used. Plasma cooling at this stage is provided by the energy exchange with the jet. The opacity effects in radiation losses are found to be important in the energy balance calculations. The magnetic surfaces in contact with the jet are cooled significantly; however, the temperature as well as the electric conductivity, remains high. The cooling front propagates towards the plasma centre. It has been shown that the cooling front is accompanied by strongly localized 'shark fin-like' perturbation in toroidal current density profile. The simplified cylindrical model shows that the cooling front is able to produce the internal kink-like mode with growth rate significantly higher than the tearing mode. The unstable kink perturbation obtained is non-resonant for any magnetic surface, both inside the plasma column, and in the vacuum space outside the separatrix. The mode disturbs mainly the core region. The growth time of the 'shark fin-like' mode is higher than the Alfven time by a factor of 10-100 for DIII-D parameters

Serum/plasma methylmercury determination by isotope dilution gas chromatography-inductively coupled plasma mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Baxter, Douglas C., E-mail: douglas.baxter@alsglobal.com [ALS Scandinavia AB, Aurorum 10, 977 75 Lulea (Sweden); Faarinen, Mikko [ALS Scandinavia AB, Aurorum 10, 977 75 Lulea (Sweden); Osterlund, Helene; Rodushkin, Ilia [ALS Scandinavia AB, Aurorum 10, 977 75 Lulea (Sweden); Division of Geosciences, Lulea University of Technology, 977 87 Lulea (Sweden); Christensen, Morten [ALS Scandinavia AB, Maskinvaegen 2, 183 53 Taeby (Sweden)

2011-09-09

Highlights: {center_dot} We determine methylmercury in serum and plasma using isotope dilution calibration. {center_dot} Separation by gas chromatography and detection by inductively coupled plasma mass spectrometry. {center_dot} Data for 50 specimens provides first reference range for methylmercury in serum. {center_dot} Serum samples shown to be stable for 11 months in refrigerator. - Abstract: A method for the determination of methylmercury in plasma and serum samples was developed. The method uses isotope dilution with {sup 198}Hg-labeled methylmercury, extraction into dichloromethane, back-extraction into water, aqueous-phase ethylation, purge and trap collection, thermal desorption, separation by gas chromatography, and mercury isotope specific detection by inductively coupled plasma mass spectrometry. By spiking 2 mL sample with 1.2 ng tracer, measurements in a concentration interval of (0.007-2.9) {mu}g L{sup -1} could be performed with uncertainty amplification factors <2. A limit of quantification of 0.03 {mu}g L{sup -1} was estimated at 10 times the standard deviation of concentrations measured in preparation blanks. Within- and between-run relative standard deviations were <10% at added concentration levels of 0.14 {mu}g L{sup -1}, 0.35 {mu}g L{sup -1} and 2.8 {mu}g L{sup -1}, with recoveries in the range 82-110%. Application of the method to 50 plasma/serum samples yielded a median (mean; range) concentration of methylmercury of 0.081 (0.091; <0.03-0.19) {mu}g L{sup -1}. This is the first time methylmercury has been directly measured in this kind of specimen, and is therefore the first estimate of a reference range.

Acid phosphatase and lipid peroxidation in human cataractous lens epithelium

Directory of Open Access Journals (Sweden)

Vasavada Abhay

1993-01-01

Full Text Available The anterior lens epithelial cells undergo a variety of degenerative and proliferative changes during cataract formation. Acid phosphatase is primarily responsible for tissue regeneration and tissue repair. The lipid hydroperoxides that are obtained by lipid peroxidation of polysaturated or unsaturated fatty acids bring about deterioration of biological membranes at cellular and tissue levels. Acid phosphatase and lipid peroxidation activities were studied on the lens epithelial cells of nuclear cataract, posterior subcapsular cataract, mature cataract, and mixed cataract. Of these, mature cataractous lens epithelium showed maximum activity for acid phosphatase (516.83 moles of p-nitrophenol released/g lens epithelium and maximum levels of lipid peroxidation (86.29 O.D./min/g lens epithelium. In contrast, mixed cataractous lens epithelium showed minimum activity of acid phosphatase (222.61 moles of p-nitrophenol released/g lens epithelium and minimum levels of lipid peroxidation (54.23 O.D./min/g lens epithelium. From our study, we correlated the maximum activity of acid phosphatase in mature cataractous lens epithelium with the increased areas of superimposed cells associated with the formation of mature cataract. Likewise, the maximum levels of lipid peroxidation in mature cataractous lens epithelium was correlated with increased permeability of the plasma membrane. Conversely, the minimum levels of lipid peroxidation in mixed cataractous lens epithelium makes us presume that factors other than lipid peroxidation may also account for the formation of mixed type of cataract.

The Effects of Gas Composition on the Atmospheric Pressure Plasma Jet Modification of Polyethylene Films

International Nuclear Information System (INIS)

Sun Jie; Qiu Yiping

2015-01-01

Polyethylene (PE) films are treated using an atmospheric pressure plasma jet (APPJ) with He or He/O 2 gas for different periods of time. The influence of gas type on the plasma-polymer interactions is studied. The surface contact angle of the PE film can be effectively lowered to 58° after 20 s of He/O 2 plasma treatment and then remains almost unchanged for longer treatment durations, while, for He plasma treatment, the film surface contact angle drops gradually to 47° when the time reaches 120 s. Atomic force microscopy (AFM) results show that the root mean square (RMS) roughness was significantly higher for the He/O 2 plasma treated samples than for the He plasma treated counterparts, and the surface topography of the He/O 2 plasma treated PE films displays evenly distributed dome-shaped small protuberances. Chemical composition analysis reveals that the He plasma treated samples have a higher oxygen content but a clearly lower percentage of −COO than the comparable He/O 2 treated samples, suggesting that differences exist in the mode of incorporating oxygen between the two gas condition plasma treatments. Electron spin resonance (ESR) results show that the free radical concentrations of the He plasma treated samples were clearly higher than those of the He/O 2 plasma treated ones with other conditions unchanged. (paper)

Lipoperoxides, alpha-tocopherol and ceruloplasmin in gamma-irradiated blood plasma

International Nuclear Information System (INIS)

Aladzhov, E.; Popzakharieva, V.

1995-01-01

Ceruloplasmin, alpha-tocopherol and lipid peroxide concentrations are evaluated in blood plasma for transfusion following exposure to irradiation with 60 Co gamma rays at doses 23, 50, 100 and 200 Gy. In plasma exposed to irradiation an increase in lipid peroxides and decrease in alpha-tocopherol and ceruloplasmin are observed. The addition of 2.3 U/ml ceruloplasmin to plasma prior to irradiation reduces the quantity of lipid peroxides and protects alpha-tocopherol. The possible explanation is that the metal helates prevent the formation of free hydroxyl radicals and thus inhibit the oxidation of lipid membranes. 15 refs., 1 tab. (author)

Surface modification and stability of detonation nanodiamonds in microwave gas discharge plasma

International Nuclear Information System (INIS)

Stanishevsky, Andrei V.; Walock, Michael J.; Catledge, Shane A.

2015-01-01

Graphical abstract: - Highlights: • Single and binary gas plasma modification of nanodiamond powders studied. • Temperature-dependent effect of N 2 and N 2 /H 2 plasma reported for the first time. • Role of H 2 in H 2 /N 2 and H 2 /O 2 plasma modification of nanodiamond discussed. - Abstract: Detonation nanodiamonds (DND), with low hydrogen content, were exposed to microwave plasma generated in pure H 2 , N 2 , and O 2 gases and their mixtures, and investigated using X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Raman, and X-ray photoelectron spectroscopies. Considerable alteration of the DND surface was observed under the plasma conditions for all used gases, but the diamond structure of the DND particle core was preserved in most cases. The stabilizing effect of H 2 in H 2 /N 2 and H 2 /O 2 binary gas plasmas on the DND structure and the temperature-dependent formation of various CNH x surface groups in N 2 and H 2 /N 2 plasmas were observed and discussed for the first time. DND surface oxidation and etching were the main effects of O 2 plasma, whereas the N 2 plasma led to DND surfaces rich in amide groups below 1073 K and nitrile groups at higher temperatures. Noticeable graphitization of the DND core structure was detected only in N 2 plasma when the substrate temperature was above 1103 K.

Laser-Irradiated Gas Puff Target Plasma Modeling

Czech Academy of Sciences Publication Activity Database

Vrba, Pavel; Vrbová, M.

2014-01-01

Roč. 42, č. 10 (2014), s. 2600-2601 ISSN 0093-3813 R&D Projects: GA ČR GAP102/12/2043 Grant - others:GA MŠk(CZ) CZ.1.07/2.3.00/20.0092 Institutional support: RVO:61389021 Keywords : Gas puff laser plasma * water window radiation source * RHMD code Z* Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.101, year: 2014 http://ieeexplore.ieee.org

Reactive species output of a plasma jet with a shielding gas device—combination of FTIR absorption spectroscopy and gas phase modelling

International Nuclear Information System (INIS)

Schmidt-Bleker, A; Winter, J; Iseni, S; Dünnbier, M; Reuter, S; Weltmann, K-D

2014-01-01

In this work, a simple modelling approach combined with absorption spectroscopy of long living species generated by a cold atmospheric plasma jet yields insight into relevant gas phase chemistry. The reactive species output of the plasma jet is controlled using a shielding gas device. The shielding gas is varied using mixtures of oxygen and nitrogen at various humidity levels. Through the combination of Fourier transform infrared (FTIR) spectroscopy, computational fluid dynamics (CFD) simulations and zero dimensional kinetic modelling of the gas phase chemistry, insight into the underlying reaction mechanisms is gained. While the FTIR measurements yield absolute densities of ozone and nitrogen dioxide in the far field of the jet, the kinetic simulations give additional information on reaction pathways. The simulation is fitted to the experimentally obtained data, using the CFD simulations of the experimental setup to estimate the correct evaluation time for the kinetic simulation. It is shown that the ozone production of the plasma jet continuously rises with the oxygen content in the shielding gas, while it significantly drops as humidity is increased. The production of nitrogen dioxide reaches its maximum at about 30% oxygen content in the shielding gas. The underlying mechanisms are discussed based on the simulation results. (paper)

Experimental study of the effect of gas nature on plasma arc cutting of mild steel

International Nuclear Information System (INIS)

Kavka, T; Mašláni, A; Hrabovský, M; Křenek, P; Stehrer, T; Pauser, H

2013-01-01

This paper is devoted to the experimental investigation of arc cutting of mild steel using plasmas generated in gas and liquid media. Due to different chemical compositions, the examined media have different thermophysical properties, which affect the properties of the generated plasma and cutting performance. The experiments are performed on 15 mm mild steel plates using commercial equipment at 60 A to approach real operation conditions in application areas. The studied gases are chosen according to recommendations of the world's leading manufacturers of arc cutting equipment for mild steel. Specific differences between plasma gases are discussed from the point of view of properties of the gas and the generated plasma, amount of removed material, kerf shape and overall energy balance of the cutting process. The paper describes the role of exothermic reaction of iron oxidation for oxygen cutting and explains its neglect for liquid cutting. This paper explains the potential of facilitating the cutting process by modification of the plasma gas chemical composition and flow rate. (paper)

Effects of gas temperature in the plasma layer on RONS generation in array-type dielectric barrier discharge at atmospheric pressure

Science.gov (United States)

Yoon, Sung-Young; Yi, Changho; Eom, Sangheum; Park, Seungil; Kim, Seong Bong; Ryu, Seungmin; Yoo, Suk Jae

2017-12-01

In this work, we studied the control of plasma-produced species under a fixed gas composition (i.e., ambient air) in a 10 kHz-driven array-type dielectric barrier atmospheric-pressure plasma discharge. Instead of the gas composition, only the gas velocity was controlled. Thus, the plasma-maintenance cost was considerably lower than methods such as external N2 or O2 injection. The plasma-produced species were monitored using Fourier transformed infrared spectroscopy. The discharge properties were measured using a voltage probe, current probe, infrared camera, and optical emission spectroscopy. The results showed that the major plasma products largely depend on the gas temperature in the plasma discharge layer. The gas temperature in the plasma discharge layer was significantly different to the temperature of the ceramic adjacent to the plasma discharge layer, even in the small discharge power density of ˜15 W/cm2 or ˜100 W/cm3. Because the vibrational excitation of N2 was suppressed by the higher gas flow, the major plasma-produced species shifted from NOx in low flow to O3 in high flow.

Degradation of nitride coatings in low-pressure gas discharge plasma

Science.gov (United States)

Ivanov, Yurii; Shugurov, Vladimir; Krysina, Olga; Petrikova, Elizaveta; Tolkachev, Oleg

2017-12-01

The paper provides research data on the defect structure, mechanical characteristics, and tribological properties of commercially pure VT1-0 titanium exposed to surface modification on a COMPLEX laboratory electron-ion plasma setup which allows nitriding, coating deposition, and etching in low-pressure gas discharge plasma in a single vacuum cycle. It is shown that preliminary plasma nitriding forms a columnar Ti2N phase in VT1-0 titanium and that subsequent TiN deposition results in a thin nanocrystalline TiN layer. When the coating-substrate system is etched, the coating fails and the tribological properties of the material degrade greatly.

Interferometric analysis of laboratory photoionized plasmas utilizing supersonic gas jet targets.

Science.gov (United States)

Swanson, Kyle James; Ivanov, Vladimir; Mancini, Roberto; Mayes, Daniel C.

2018-06-01

Photoionized plasmas are an important component of active galactic nuclei, x-ray binary systems and other astrophysical objects. Laboratory produced photoionized plasmas have mainly been studied at large scale facilities, due to the need for high intensity broadband x-ray flux. Using supersonic gas jets as targets has allowed university scale pulsed power generators to begin similar research. The two main advantages of this approach with supersonic gas jets include: possibility of a closer location to the x-ray source and no attenuation related to material used for containment and or tamping. Due to these factors, this experimental platform creates a laboratory environment that more closely resembles astrophysical environments. This system was developed at the Nevada Terawatt Facility using the 1 MA pulsed power generator Zebra. Neon, argon, and nitrogen supersonic gas jets are produced approximately 7-8mm from the z-pinch axis. The high intensity broadband x-ray flux produced by the collapse of the z-pinch wire array implosion irradiates the gas jet. Cylindrical wire arrays are made with 4 and 8 gold 10µm thick wire. The z-pinch radiates approximately 12-16kj of x-ray energy, with x-ray photons under 1Kev in energy. The photoionized plasma is measured via x-ray absorption spectroscopy and interferometry. A Mach-Zehnder interferometer is used to the measure neutral density of the jet prior to the zebra shot at a wavelength of 266 nm. A dual channel air-wedge shearing interferometer is used to measure electron density of the ionized gas jet during the shot, at wavelengths of 532nm and 266nm. Using a newly developed interferometric analysis tool, average ionization state maps of the plasma can be calculated. Interferometry for nitrogen and argon show an average ionization state in the range of 3-8. Preliminary x-ray absorption spectroscopy collected show neon absorption lines. This work was sponsored in part by DOE Office of Science Grant DE-SC0014451.

Note: Design and investigation of a multichannel plasma-jet triggered gas switch.

Science.gov (United States)

Tie, Weihao; Liu, Xuandong; Zhang, Qiaogen; Liu, Shanhong

2014-07-01

We described the fabrication and testing of a multichannel plasma-jet triggered gas switch (MPJTGS). A novel six-channel annular micro-plasma-gun was embedded in the trigger electrode to generate multichannel plasma jets as a nanosecond trigger pulse arrived. The gas breakdown in multiple sites of the spark gap was induced and fixed around jet orifices by the plasma jets. We tested the multichannel discharge characteristics of the MPJTGS in two working modes with charge voltage of 50 kV, trigger voltage of +40 kV (25 ns rise time), and trigger energy of 240 J, 32 J, and 2 J, respectively, at different working coefficients. Results show that the average number of discharge channels increased as the trigger energy increased, and decreased as the working coefficient decreased. At a working coefficient of 87.1% and trigger energy of 240 J, the average number of discharge channels in Mode II could reach 4.1.

Magnetically insulated ion diode with a gas-breakdown plasma anode

International Nuclear Information System (INIS)

Greenly, J.B.; Ueda, M.; Rondeau, G.D.; Hammer, D.A.

1987-12-01

An active anode plasma source has been developed for use in a magnetically insulated ion diode operated on a 10 sup(10)W pulsed power generator. This source uses an inductive voltage from a single turn coil to break down an annular gas puff produced by a supersonic nozzle. The resulting plasma is magnetically driven toward the radial insulating magnetic field in the diode accelerating gap and stagnates at a well-defined surface after about 300ns to form a plasma anode layer defined by magnetic flux surfaces. An ion beam is then extracted from this plasma layer by applying a 150kV, 1 μs pulse to the accelerating gap. Optimization of the timing of the gas puff, the plasma production discharge and the high voltage pulse has resulted in 1μs duration 75-150KeV ion beam pulses with >100A/cm sup(2) peak ion current density over an area of about 400cm sup(2). Up to 5J/cm sup(2) has been collected by a 4cm sup(2) calorimeter. The diode impedance history can be varied so that rising, flat, and falling voltage pulse waveforms can be produced. Streak photographs of beamlets impinging on a scintillator and time integrated targets both show beam divergence angles ≤3 sup(0). However, under certain operating conditions, large excursions (∼25 sup(0)) in mean aiming angle on time scales of 20-200ns are observed. (author)

Dynamic behavior of polydisperse dust system in cryogenic gas discharge complex plasmas

NARCIS (Netherlands)

Antipov, S.N.; Schepers, L.P.T.; Vasiliev, M.M.; Petrov, O.F.

2016-01-01

Complex (dusty) plasmas of micron-sized CeO2 polydisperse particles in dc glow discharges at 77 and ∼ 10 K were experimentally investigated. It was obtained that dust structure in cryogenic gas discharge plasma can be a mixture of two fractions (components) with completely different dust ordering

Surface modification and stability of detonation nanodiamonds in microwave gas discharge plasma

Energy Technology Data Exchange (ETDEWEB)

Stanishevsky, Andrei V., E-mail: astan@uab.edu; Walock, Michael J.; Catledge, Shane A.

2015-12-01

Graphical abstract: - Highlights: • Single and binary gas plasma modification of nanodiamond powders studied. • Temperature-dependent effect of N{sub 2} and N{sub 2}/H{sub 2} plasma reported for the first time. • Role of H{sub 2} in H{sub 2}/N{sub 2} and H{sub 2}/O{sub 2} plasma modification of nanodiamond discussed. - Abstract: Detonation nanodiamonds (DND), with low hydrogen content, were exposed to microwave plasma generated in pure H{sub 2}, N{sub 2}, and O{sub 2} gases and their mixtures, and investigated using X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Raman, and X-ray photoelectron spectroscopies. Considerable alteration of the DND surface was observed under the plasma conditions for all used gases, but the diamond structure of the DND particle core was preserved in most cases. The stabilizing effect of H{sub 2} in H{sub 2}/N{sub 2} and H{sub 2}/O{sub 2} binary gas plasmas on the DND structure and the temperature-dependent formation of various CNH{sub x} surface groups in N{sub 2} and H{sub 2}/N{sub 2} plasmas were observed and discussed for the first time. DND surface oxidation and etching were the main effects of O{sub 2} plasma, whereas the N{sub 2} plasma led to DND surfaces rich in amide groups below 1073 K and nitrile groups at higher temperatures. Noticeable graphitization of the DND core structure was detected only in N{sub 2} plasma when the substrate temperature was above 1103 K.

Reduction of nitrogen oxides from simulated exhaust gas by using plasma-catalytic process

International Nuclear Information System (INIS)

Mok, Young Sun; Koh, Dong Jun; Shin, Dong Nam; Kim, Kyong Tae

2004-01-01

Removal of nitrogen oxides (NO x ) using a nonthermal plasma reactor (dielectric-packed bed reactor) combined with monolith V 2 O 5 /TiO 2 catalyst was investigated. The effect of initial NO x concentration, feed gas flow rate (space velocity), humidity, and reaction temperature on the removal of NO x was examined. The plasma reactor used can be energized by either ac or pulse voltage. An attempt was made to utilize the electrical ignition system of an internal combustion engine as a high-voltage pulse generator for the plasma reactor. When the plasma reactor was energized by the electrical ignition system, NO was readily oxidized to NO 2 . Performance was as good as with ac energization. Increasing the fraction of NO 2 in NO x , which is the main role of the plasma reactor, largely enhanced the NO x removal efficiency. In the plasma-catalytic reactor, the increases in initial NO x concentration, space velocity (feed gas flow rate) and humidity lowered the NO x removal efficiency. However, the reaction temperature in the range up to 473 K did not significantly affect the NO x removal efficiency in the presence of plasma discharge

Development of a laser-induced plasma probe to measure gas phase plasma signals at high pressures and temperatures

International Nuclear Information System (INIS)

Gounder, J.D.; Kutne, P.; Meier, W.

2012-01-01

The ability of laser induced breakdown spectroscopy (LIBS) technique for on line simultaneous measurement of elemental concentrations has led to its application in a wide number of processes. The simplicity of the technique allows its application to harsh environments such as present in boilers, furnaces and gasifiers. This paper presents the design of a probe using a custom optic which transforms a round beam into a ring (Donut) beam, which is used for forming a plasma in an atmosphere of nitrogen at high pressure (20 bar) and temperature (200 °C). The LIBS experiments were performed using a high pressure cell to characterize and test the effectiveness of the donut beam transmitted through the LIBS probe and collect plasma signal in back scatter mode. The first tests used the second harmonic of a Nd:YAG laser, pulse width 7 ns, to form a plasma in nitrogen gas at five different pressures (1, 5, 10, 15 and 20 bar) and three different gas temperatures (25, 100 and 200 °C). The uniqueness of this probe is the custom made optic used for reshaping the round laser beam into a ring (Donut) shaped laser beam, which is fed into the probe and focused to form a plasma at the measurement point. The plasma signal is collected and collimated using the laser focusing lens and is reflected from the laser beam axis onto an achromatic lens by a high reflection mirror mounted in the center section of the donut laser beam. The effect of gas pressure and temperature on N(I) lines in the high pressure cell experiment shows that the line intensity decreases with pressure and increases with temperature. Mean plasma temperature was calculated using the ratios of N(I) line intensities ranging from 7400 K to 8900 K at 1 bar and 2400 K to 3200 K at 20 bar for the three different gas temperatures. The results show that as a proof of principle the donut beam optics in combination with the LIBS probe can be used for performing extensive LIBS measurements in well controlled laboratory

Development of a laser-induced plasma probe to measure gas phase plasma signals at high pressures and temperatures

Energy Technology Data Exchange (ETDEWEB)

Gounder, J.D., E-mail: James.Gounder@dlr.de; Kutne, P.; Meier, W.

2012-08-15

The ability of laser induced breakdown spectroscopy (LIBS) technique for on line simultaneous measurement of elemental concentrations has led to its application in a wide number of processes. The simplicity of the technique allows its application to harsh environments such as present in boilers, furnaces and gasifiers. This paper presents the design of a probe using a custom optic which transforms a round beam into a ring (Donut) beam, which is used for forming a plasma in an atmosphere of nitrogen at high pressure (20 bar) and temperature (200 Degree-Sign C). The LIBS experiments were performed using a high pressure cell to characterize and test the effectiveness of the donut beam transmitted through the LIBS probe and collect plasma signal in back scatter mode. The first tests used the second harmonic of a Nd:YAG laser, pulse width 7 ns, to form a plasma in nitrogen gas at five different pressures (1, 5, 10, 15 and 20 bar) and three different gas temperatures (25, 100 and 200 Degree-Sign C). The uniqueness of this probe is the custom made optic used for reshaping the round laser beam into a ring (Donut) shaped laser beam, which is fed into the probe and focused to form a plasma at the measurement point. The plasma signal is collected and collimated using the laser focusing lens and is reflected from the laser beam axis onto an achromatic lens by a high reflection mirror mounted in the center section of the donut laser beam. The effect of gas pressure and temperature on N(I) lines in the high pressure cell experiment shows that the line intensity decreases with pressure and increases with temperature. Mean plasma temperature was calculated using the ratios of N(I) line intensities ranging from 7400 K to 8900 K at 1 bar and 2400 K to 3200 K at 20 bar for the three different gas temperatures. The results show that as a proof of principle the donut beam optics in combination with the LIBS probe can be used for performing extensive LIBS measurements in well controlled

Spatial profiling of ion and neutral excitation in noble gas electron cyclotron resonance plasmas

International Nuclear Information System (INIS)

Rhoades, R.L.; Gorbatkin, S.M.

1994-01-01

Optical emission from neutrals and ions of several noble gases has been profiled in an electron cyclotron resonance plasma system. In argon plasmas with a net microwave power of 750 W, the neutral (696.5-nm) and ion (488-nm) emission profiles are slightly center peaked at 0.32 mTorr and gradually shift to a hollow appearance at 2.5 mTorr. Neon profiles show a similar trend from 2.5 to 10.0 mTorr. For the noble gases, transition pressure scales with the ionization potential of the gas, which is consistent with neutral depletion. Studies of noble gas mixtures, however, indicate that neutral depletion is not always dominant in the formation of hollow profiles. For Kr/Ar, Ar/Ne, and Ne/He plasmas, the majority gas tends to set the overall shape of the profile at any given pressure. For the conditions of the current system, plasma density appears to be more dominant than electron temperature in the formation of hollow profiles. The general method described is also a straightforward, inexpensive technique for measuring the spatial distribution of power deposited in plasmas, particularly where absolute scale can be calibrated by some other means

Effects of Dietary Lycopene Supplementation on Plasma Lipid Profile, Lipid Peroxidation and Antioxidant Defense System in Feedlot Bamei Lamb

Directory of Open Access Journals (Sweden)

Hongqin Jiang

2015-07-01

Full Text Available Lycopene, a red non-provitamin A carotenoid, mainly presenting in tomato and tomato byproducts, has the highest antioxidant activity among carotenoids because of its high number of conjugated double bonds. The objective of this study was to investigate the effect of lycopene supplementation in the diet on plasma lipid profile, lipid peroxidation and antioxidant defense system in feedlot lamb. Twenty-eight Bamei male lambs (90 days old were divided into four groups and fed a basal diet (LP0, 40:60 roughage: concentrate or the basal diet supplemented with 50, 100, and 200 mg/kg lycopene. After 120 days of feeding, all lambs were slaughtered and sampled. Dietary lycopene supplementation significantly reduced the levels of plasma total cholesterol (p0.05. The levels of TG (p<0.001 and LDL-C (p<0.001 were decreased with the feeding time extension, and both showed a linear trend (p<0.01. Malondialdehyde level in plasma and liver decreased linearly with the increase of lycopene inclusion levels (p<0.01. Dietary lycopene intake linearly increased the plasma antioxidant vitamin E level (p<0.001, total antioxidant capacity (T-AOC, p<0.05, and activities of catalase (CAT, p<0.01, glutathione peroxidase (GSH-Px, p<0.05 and superoxide dismutase (SOD, p<0.05. The plasma T-AOC and activities of GSH-Px and SOD decreased with the extension of the feeding time. In liver, dietary lycopene inclusion showed similar antioxidant effects with respect to activities of CAT (p<0.05, linearly and SOD (p<0.001, linearly. Therefore, it was concluded that lycopene supplementation improved the antioxidant status of the lamb and optimized the plasma lipid profile, the dosage of 200 mg lycopene/kg feed might be desirable for growing lambs to prevent environment stress and maintain normal physiological metabolism.

Dust-acoustic instability in an inductive gas-discharge plasma

International Nuclear Information System (INIS)

Zobnin, A.V.; Usachev, A.D.; Petrov, O.F.; Fortov, V.E.

2002-01-01

Spontaneous excitation of a dust-particle density wave is observed in a dust cloud levitating in the region of the diffused edge of an rf inductive low-pressure gas-discharge plasma. The main physical parameters of this wave and of the background plasma are measured. The analytic model proposed for the observed phenomenon is based on the theory of dust sound and successfully correlates with experimental data in a wide range of experimental conditions. The effect of variable charge of dust particles on the evolution of the observed dust-plasma instability is studied analytically. It is shown that the necessary condition for the development of the dust-acoustic instability is the presence of a dc electric field in the dust cloud region

EFFECT OF PHYSICAL EXERCISE ON LIPID PEROXIDATION AND ANTIOXIDANT ASCORBIC ACID DEFENSE

Directory of Open Access Journals (Sweden)

Ljiljana M. Popović

2006-06-01

Full Text Available Strenuous exercises greatly increase oxygen consumption in the whole body, especially in skeletal muscles. Large part of oxygen consumption is reduced to H2O and ATP, but smaller part (2-5% results in an increased leakage of electrons from the mitochondrial respiratory chain, forming various reactive oxygen species ─ ROS (O2˙¯, H2O2 i OH˙. These free radicals are capable of triggering a chain of damaging biochemical and physiological reactions (oxidative stress, lipid peroxidation,as a base for skeletal muscles damage after exercise. MDA (malondialdehide is a marker of exercise induced lipid peroxidation process. L–ascorbic acid is a major aqueous-phase antioxidant. To estimate antioxidant role of ascorbic acid we use rate between dehidroascorbate and ascorbate. In this paper those markers were determinated in 30 students, in rest and after treadmill running protocol (Bruce Treadmill Protocol. It was found that after the treadmill test , plasma MDA level had increased from 3,04 to 4,39 μM/L. Plasma ascorbic acid was also found to be higher after the treadmill test comparing to rest level (from 55,4 to 67,6 μM/L. DHA/A level in rest was 1,62 and after treadmill test it increased to 2,05. These results suggests that strenuous exercise increased process of lipid peroxidation, but in the same time increased ascorbic acid level in plasma and DHA/A rate indicates stronger antioxidant defense system.

Thermochemistry of cyclic acetone peroxides

Energy Technology Data Exchange (ETDEWEB)

Sinditskii, V.P., E-mail: vps@rctu.ru [Mendeleev University of Chemical Technology, 9 Miusskaya Square, 125047 Moscow (Russian Federation); Kolesov, V.I.; Egorshev, V.Yu.; Patrikeev, D.I. [Mendeleev University of Chemical Technology, 9 Miusskaya Square, 125047 Moscow (Russian Federation); Dorofeeva, O.V. [Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow (Russian Federation)

2014-06-01

Highlights: • Old data on DADP and TATP enthalpies of formation have been revised. • Combining Gaussian-4 (G4) theory with an isodesmic reaction scheme allowed calculated enthalpies of formation of TATP and DADP. • Oxygen bomb calorimetry measurements allowed experimental enthalpies of formation of the peroxides. • Both experimental and calculated values show a satisfactory agreement between each other. • The newly obtained enthalpies reasonably account for the observed derivative parameters: heats of decomposition, combustion, and explosion. - Abstract: Two potentially initiating explosive peroxides, diacetonediperoxide (DADP) and triacetonetriperoxide (TATP), were studied in respect to their thermochemical properties. To get the internally self-consistent estimations of gas-phase enthalpy of formation of DADP and TATP, their values were calculated by combining Gaussian-4 (G4) theory with an isodesmic reaction scheme. The energies of combustion (Δ{sub c}U) were measured and the standard enthalpies of formation (Δ{sub f}H{sub 298}{sup °}) of DADP and TATP were derived using the standard enthalpies of formation of the combustion products. The heat of explosion was measured for small low-pressed charges of the peroxides. The obtained enthalpies of formation of DADP and TATP were found to agree well with quantum chemical calculations and reasonably account for the observed derivative parameters: heats of decomposition, combustion, and detonation.

Impact of gas puffing location on density control and plasma parameters in TJ-II

International Nuclear Information System (INIS)

Tabares, F.L.; Garcia-Cortes, I.; Estrada, T.; Tafalla, D.; Hidalgo, A.; Ferreira, J.A.; Pastor, I.; Herranz, J.; Ascasibar, E.

2005-01-01

Under pure Electron Cyclotron Resonance Heating (ECRH) conditions in TJ-II plasmas (P<300 kW, 53.2 GHz, 2nd harmonic X-mode, power density < 25 W/m''3), plasma start-up and good density control are obtained only by the proper combination of wall conditions and gas puffing characteristics. Such a control is particularly critical for the optimisation of the NBI power transfer to the target plasmas. The relatively low cut-off limit is easily reached due not only to the unfavourable wall/puffing-fuelling ratio but also due to the steep density profiles developed during the Enhanced Particle Confinement (EPC) modes. These modes are triggered by the gas puffing waveform, and they cannot be achieved for high iota magnetic configurations in TJ-II. Comparative experiments under metallic and boronised wall conditions have shown that the sensitivity of the EPC modes to the puffing rate is at least partially related to the energy balance at the plasma periphery under central heating scenarios. In this work, the impact of gas-fuelling location on the plasma parameters and density control is described. For that purpose, three different fuelling locations have been investigated; broad distribution from a side ports, localized injection from long tubes at different poloidal positions and highly localized injection through a movable limiter. Edge density and temperature profiles from a broad set of diagnostics (atomic beams, reflectometry, Thompson Scattering ECE, etc...) are analysed and compared. It has been found that preventing from transition to the EPC mode is achieved by using slow puffing rates, while neutral penetration into the plasma core can be enhanced for highly localized gas sources. Wall inventory, however, has been found to pl ay a dominant role in the fuelling of the plasma under most conditions. (author)

Measurements of hydrogen gas stopping efficiency for tin ions from laser-produced plasma

Science.gov (United States)

Abramenko, D. B.; Spiridonov, M. V.; Krainov, P. V.; Krivtsun, V. M.; Astakhov, D. I.; Medvedev, V. V.; van Kampen, M.; Smeets, D.; Koshelev, K. N.

2018-04-01

Experimental studies of stopping of ion fluxes from laser-produced plasma by a low-pressure gas atmosphere are presented. A modification of the time-of-flight spectroscopy technique is proposed for the stopping cross-sectional measurements in the ion energy range of 0.1-10 keV. The application of the proposed technique is demonstrated for Sn ion stopping by H2 gas. This combination of elements is of particular importance for the development of plasma-based sources of extreme ultraviolet radiation for lithographic applications.

Lifetime and shelf life of sealed tritium-filled plasma focus chambers with gas generator

Directory of Open Access Journals (Sweden)

B.D. Lemeshko

2017-11-01

Full Text Available The paper describes the operation features of plasma focus chambers using deuterium–tritium mixture. Handling tritium requires the use of sealed, vacuum-tight plasma focus chambers. In these chambers, there is an accumulation of the impurity gases released from the inside surfaces of the electrodes and the insulator while moving plasma current sheath inside chambers interacting with β-electrons generated due to the decay of tritium. Decay of tritium is also accompanied by the accumulation of helium. Impurities lead to a decreased yield of neutron emission from plasma focus chambers, especially for long term operation. The paper presents an option of absorption type gas generator in the chamber based on porous titanium, which allows to significantly increase the lifetime and shelf life of tritium chambers. It also shows the results of experiments on the comparison of the operation of sealed plasma focus chambers with and without the gas generator. Keywords: Plasma focus, Neutron yield, Tritium-filled plasma focus chambers, PACS Codes: 29.25.-v, 52.58.Lq

Determination of amino acid and protein peroxides by the xylenol orange-Fe(III) complex

International Nuclear Information System (INIS)

Collins, J.; Craig, G.; Gebicki, J.

1996-01-01

Oxidative stress imposed on living organisms is believed to lead to the depletion of their antioxidant defences, followed by chemical changes in the cell constituents. These may ultimately develop into pathological conditions such as cancer or cardiovascular disease. An assay of peroxides which could be applied to tissues or simple tissue extracts would prove extremely useful in the studies of the phenomenon of oxidative stress. With this purpose, the authors have tested the ability of two peroxide assay techniques to measure the formation of amino acid and protein peroxides in aqueous solutions irradiated with gamma rays, using a modification of the method based on the oxidation of Fe(II)) by peroxides and complexing of the Fe(III) produced by xylenol orange. The molar extinction coefficients of the peroxides tested were determined by comparison with the well-tested iodometric assay. This work was extended to the detection of all organic peroxides in human blood plasma or serum subjected to oxidative stress, where the iodometric assay proved difficult to apply and unreliable because of the binding of iodine to the blood components. Preliminary results suggest that exposure of serum to gamma radiation leads to immediate peroxidation of the proteins, with a delay before generation of lipid peroxides

Application of epifluorescence scanning for monitoring the efficacy of protein removal by RF gas-plasma decontamination

Energy Technology Data Exchange (ETDEWEB)

Baxter, Helen C; Richardson, Patricia R; Campbell, Gaynor A; Jones, Anita C; Baxter, Robert L [School of Chemistry, Joseph Black Chemistry Building, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ (United Kingdom); Kovalev, Valeri I; Maier, Robert; Barton, James S [School of Engineering and Physical Science, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); DeLarge, Greg [Plasma Etch Inc, 3522 Arrowhead Drive, Carson City, NV 89706 (United States); Casey, Mark [Sterile Services Department, Royal Infirmary of Edinburgh, Edinburgh EH16 4AS (United Kingdom)], E-mail: r.baxter@ed.ac.uk

2009-11-15

The development of methods for measuring the efficiency of gas-plasma decontamination has lagged far behind application. An approach to measuring the efficiency of protein removal from solid surfaces using fluorescein-labelled bovine serum albumin and epifluorescence scanning (EFSCAN) is described. A method for fluorescently labelling proteins, which are adsorbed and denatured on metal surfaces, has been developed. Both approaches have been used to evaluate the efficiency of radio frequency (RF) gas-plasma decontamination protocols. Examples with 'real' surgical instruments demonstrate that an argon-oxygen RF gas-plasma treatment can routinely reduce the protein load by about three orders of magnitude beyond that achieved by current decontamination methods.

Application of epifluorescence scanning for monitoring the efficacy of protein removal by RF gas-plasma decontamination

International Nuclear Information System (INIS)

Baxter, Helen C; Richardson, Patricia R; Campbell, Gaynor A; Jones, Anita C; Baxter, Robert L; Kovalev, Valeri I; Maier, Robert; Barton, James S; DeLarge, Greg; Casey, Mark

2009-01-01

The development of methods for measuring the efficiency of gas-plasma decontamination has lagged far behind application. An approach to measuring the efficiency of protein removal from solid surfaces using fluorescein-labelled bovine serum albumin and epifluorescence scanning (EFSCAN) is described. A method for fluorescently labelling proteins, which are adsorbed and denatured on metal surfaces, has been developed. Both approaches have been used to evaluate the efficiency of radio frequency (RF) gas-plasma decontamination protocols. Examples with 'real' surgical instruments demonstrate that an argon-oxygen RF gas-plasma treatment can routinely reduce the protein load by about three orders of magnitude beyond that achieved by current decontamination methods.

Assessment of semen function and lipid peroxidation among lead exposed men

International Nuclear Information System (INIS)

Kasperczyk, Aleksandra; Kasperczyk, Slawomir; Horak, Stanislaw; Ostalowska, Alina; Grucka-Mamczar, Ewa; Romuk, Ewa; Olejek, Anita; Birkner, Ewa

2008-01-01

The study population included healthy, fertile men, employees of Zinc and Lead Metalworks (n = 63). Workers exposed to lead were divided into two groups: a group with moderate exposure to lead (ME) - blood lead level (PbB) 25-40 μg/dl and a group with high exposure to lead (HE) PbB = 40-81 μg/dl. The control group consisted of office workers with no history of occupational exposure to lead. Evaluation of lead, cadmium and zinc level in blood and seminal plasma, zinc protoporphyrin in blood (ZPP), 5-aminolevulinic acid in urine (ALA), malondialdehyde (MDA) in seminal plasma and sperm analysis were performed. No differences were noted in the concentration of cadmium and zinc in blood and seminal plasma in the study population. Lipid peroxidation in seminal plasma, represented as MDA concentration, significantly increased by about 56% in the HE group and the percentage of motile sperm cells after 1 h decreased by about 34% in comparison to the control group. No statistically significant correlation between other parameters of sperm analysis and lead exposure parameters nor between lead, cadmium and zinc concentration in blood and seminal plasma were found. A positive association between lead intoxication parameters (PbB, ZPP, lead seminal plasma) and MDA concentration in sperm plasma and inverse correlation with sperm cells motility (PbB, ZPP) was found. An increased concentration of MDA was accompanied by a drop in sperm cells motility. In conclusion, we report that high exposure to lead causes a decrease of sperm motility in men most likely as a result of increased lipid peroxidation, especially if the level in the blood surpasses the concentration of 40 μg/dl

The magnetic field application for the gas discharge plasma control in processes of surface coating and modification

International Nuclear Information System (INIS)

Asadullin, T Ya; Galeev, I G

2017-01-01

In this paper the method of magnetic field application to control the gas discharge plasma effect on the various surfaces in processes of surface coating and modification is considered. The magnetic field directed perpendicular to the direction of electric current in the gas discharge plasma channel is capable to reject this plasma channel due to action of Lorentz force on the moving electrically charged particles [1,2]. The three-dimensional spatial structure of magnetic field is created by system of necessary quantity of the magnets located perpendicular to the direction of course of electric current in the gas-discharge plasma channel. The formation of necessary spatial distribution of magnetic field makes possible to obtain a required distribution of plasma parameters near the processed surfaces. This way of the plasma channel parameters spatial distribution management is the most suitable for application in processes of plasma impact on a surface of irregular shape and in cases when the selective impact of plasma on a part of a surface of a product is required. It is necessary to apply automated computer management of the process parameters [3] to the most effective plasma impact. (paper)

Effects of H2/O2 mixed gas plasma treatment on electrical and optical property of indium tin oxide

International Nuclear Information System (INIS)

Kim, Jun Young; Lee, Dong-Min; Kim, Jae-Kwan; Yang, Su-Hwan; Lee, Ji-Myon

2013-01-01

Highlights: ► The specific resistivity of ITO was enhanced by H 2 + O 2 mixed gas plasma treatment. ► The transmittance was same as that of untreated ITO after plasma treatment. ► The process was carried out at room temperature without any step of post-treatment. - Abstract: This study examined the effects of H 2 and H 2 + O 2 mixed gas plasma treatment on the properties of ITO films. The films were deposited on corning glass by RF magnetron sputtering under Ar and Ar/O 2 mixed gas ambient. After a H 2 plasma treatment, the ITO films showed an improved specific resistance due to the formation of oxygen vacancies acting as shallow donors, but showed quenched transmittance due to the formation of agglomerated metals on the surface. After an H 2 + O 2 mixed gas plasma treatment, the specific resistance of the film was improved without deteriorating transmittance. The enhanced specific resistance by mixed gas plasma treatment was attributed to the formation of free electrons by the incorporation of H in the lattice.

Effect of Terminalia chebula fruit extract on lipid peroxidation and ...

African Journals Online (AJOL)

SERVER

2007-08-20

Aug 20, 2007 ... products mainly edible vegetables and spices, have a key role in chemopreventers ... protein; dunit/minute/mg protein ; eµg/mg protein; fn moles of H2O2 ... induce peroxidation of cell membrane lipids (Bhattacharya et al., 1999). .... catalase – like activities in seminal plasma and spermatozoa. Int. J. Androl.

Atmospheric-pressure plasma jets: Effect of gas flow, active species, and snake-like bullet propagation

Energy Technology Data Exchange (ETDEWEB)

Wu, S.; Wang, Z.; Huang, Q.; Tan, X.; Lu, X. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Ostrikov, K. [CSIRO Materials Science and Engineering, PO Box 218, Lindfield NSW 2070 (Australia); School of Physics, University of Sydney, Sydney NSW 2006 (Australia); State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

2013-02-15

Cold atmospheric-pressure plasma jets have recently attracted enormous interest owing to numerous applications in plasma biology, health care, medicine, and nanotechnology. A dedicated study of the interaction between the upstream and downstream plasma plumes revealed that the active species (electrons, ions, excited OH, metastable Ar, and nitrogen-related species) generated by the upstream plasma plume enhance the propagation of the downstream plasma plume. At gas flows exceeding 2 l/min, the downstream plasma plume is longer than the upstream plasma plume. Detailed plasma diagnostics and discharge species analysis suggest that this effect is due to the electrons and ions that are generated by the upstream plasma and flow into the downstream plume. This in turn leads to the relatively higher electron density in the downstream plasma. Moreover, high-speed photography reveals a highly unusual behavior of the plasma bullets, which propagate in snake-like motions, very differently from the previous reports. This behavior is related to the hydrodynamic instability of the gas flow, which results in non-uniform distributions of long-lifetime active species in the discharge tube and of surface charges on the inner surface of the tube.

A study on rare gas - oxygen reactions excited by low temperature plasma

Energy Technology Data Exchange (ETDEWEB)

Ogawa, Hiroaki; Kiuchi, Kiyoshi; Saburi, Tei; Fukaya, Kiyoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2001-03-01

The concentration of radioactive rare gases like Xe and Kr in nuclear fuels on PWRs and BWRs increases promptly with dependent on the burn-up ratio. These gases are affect to the long performance of nuclear fuel elements due to accumulate in gap between cladding and fuel, because it has the low thermal conductivity. It is also required to develop the practical means to correct these gases including in the off-gas in nuclear plants for inhibiting the environmental pollution. On the present study, we carried out the fundamental research to evaluate the chemical reactivity of these gases under heavy irradiation. We proposed the new excitation mechanism of these gases by expecting the formation of low energy plasma under irradiation. The chemical reactivity on rare gas-oxygen system was examined by using the low energy plasma driven reaction apparatus installed the RF excitation source. The density of electrons and lower pressure limit for the RF excitation was depended on the ionization energy of each gas. It is clarified that Xe is easy to form gaseous oxide due to the high excitation efficiency in low energy plasma. (author)

Measurement of formic acid, acetic acid and hydroxyacetaldehyde, hydrogen peroxide, and methyl peroxide in air by chemical ionization mass spectrometry: airborne method development

Science.gov (United States)

Treadaway, Victoria; Heikes, Brian G.; McNeill, Ashley S.; Silwal, Indira K. C.; O'Sullivan, Daniel W.

2018-04-01

A chemical ionization mass spectrometry (CIMS) method utilizing a reagent gas mixture of O2, CO2, and CH3I in N2 is described and optimized for quantitative gas-phase measurements of hydrogen peroxide (H2O2), methyl peroxide (CH3OOH), formic acid (HCOOH), and the sum of acetic acid (CH3COOH) and hydroxyacetaldehyde (HOCH2CHO; also known as glycolaldehyde). The instrumentation and methodology were designed for airborne in situ field measurements. The CIMS quantification of formic acid, acetic acid, and hydroxyacetaldehyde used I- cluster formation to produce and detect the ion clusters I-(HCOOH), I-(CH3COOH), and I-(HOCH2CHO), respectively. The CIMS also produced and detected I- clusters with hydrogen peroxide and methyl peroxide, I-(H2O2) and I-(CH3OOH), though the sensitivity was lower than with the O2- (CO2) and O2- ion clusters, respectively. For that reason, while the I- peroxide clusters are presented, the focus is on the organic acids. Acetic acid and hydroxyacetaldehyde were found to yield equivalent CIMS responses. They are exact isobaric compounds and indistinguishable in the CIMS used. Consequently, their combined signal is referred to as the acetic acid equivalent sum. Within the resolution of the quadrupole used in the CIMS (1 m/z), ethanol and 1- and 2-propanol were potential isobaric interferences to the measurement of formic acid and the acetic acid equivalent sum, respectively. The CIMS response to ethanol was 3.3 % that of formic acid and the response to either 1- or 2-propanol was 1 % of the acetic acid response; therefore, the alcohols were not considered to be significant interferences to formic acid or the acetic acid equivalent sum. The multi-reagent ion system was successfully deployed during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ) in 2014. The combination of FRAPPÉ and laboratory calibrations allowed for the post-mission quantification of formic acid and the acetic acid equivalent sum observed during the Deep

Atmospheric pulsed laser deposition of plasmonic nanoparticle films of silver with flowing gas and flowing atmospheric plasma

Science.gov (United States)

Khan, T. M.; Pokle, A.; Lunney, J. G.

2018-04-01

Two methods of atmospheric pulsed laser deposition of plasmonic nanoparticle films of silver are described. In both methods the ablation plume, produced by a 248 nm, 20 ns excimer laser in gas, is strongly confined near the target and forms a nanoparticle aerosol. For both the flowing gas, and the atmospheric plasma from a dielectric barrier discharge plasma source, the aerosol is entrained in the flow and carried to a substrate for deposition. The nanoparticle films produced by both methods were examined by electron microscopy and optical absorption spectroscopy. With plasma assistance, the deposition rate was significantly enhanced and the film morphology altered. With argon gas, isolated nanoparticles of 20 nm size were obtained, whereas in argon plasma, the nanoparticles are aggregated in clusters of 90 nm size. Helium gas also leads to the deposition of isolated nanoparticles, but with helium plasma, two populations of nanoparticles are observed: one of rounded particles with a mean size of 26 nm and the other of faceted particles with a mean size 165 nm.

Current distribution measurements inside an electromagnetic plasma gun operated in a gas-puff mode

OpenAIRE

Poehlmann, Flavio R.; Cappelli, Mark A.; Rieker, Gregory B.

2010-01-01

Measurements are presented of the time-dependent current distribution inside a coaxial electromagnetic plasma gun. The measurements are carried out using an array of six axially distributed dual-Rogowski coils in a balanced circuit configuration. The radial current distributions indicate that operation in the gas-puff mode, i.e., the mode in which the electrode voltage is applied before injection of the gas, results in a stationary ionization front consistent with the presence of a plasma def...

Plasma Gasification of Wood and Production of Gas with Low Content of Tar

Czech Academy of Sciences Publication Activity Database

Hlína, Michal; Hrabovský, Milan; Kopecký, Vladimír; Konrád, Miloš; Kavka, Tetyana; Skoblja, S.

2006-01-01

Roč. 56, suppl. B (2006), s. 1179-1184 ISSN 0011-4626. [Symposium on Plasma Physics and Technology/22nd./. Praha, 26.6.2006-29.6.2006] R&D Projects: GA ČR GA202/05/0669 Institutional research plan: CEZ:AV0Z20430508 Keywords : tar * plasma * biomass gasification Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.568, year: 2006

Low-Cost Real-Time Gas Monitoring Using a Laser Plasma Induced by a Third Harmonic Q-Switched Nd-YAG Laser

Directory of Open Access Journals (Sweden)

Syahrun Nur Abdulmadjid

2005-11-01

Full Text Available A gas plasma induced by a third harmonic Nd-YAG laser with relatively low pulsed energy (about 10 mJ has favorable characteristics for gas analysis due to its low background characteristics, nevertheless a high power fundamental Nd-YAG laser (100-200 mJ is widely used for laser gas breakdown spectroscopy. The air plasma can be used as a low-cost real-time gas monitoring system such that it can be used to detect the local absolute humidity, while a helium plasma can be used for gas analysis with a high level of sensitivity. A new technique using a helium plasma to improve laser ablation emission spectroscopy is proposed. Namely, the third harmonic Nd-YAG laser is focused at a point located some distance from the target in the 1-atm helium surrounding gas. By using this method, the ablated vapor from the target is excited through helium atoms in a metastable state in the helium plasma.

Production of ammonia from plasma-catalytic decomposition of urea: Effects of carrier gas composition.

Science.gov (United States)

Fan, Xing; Li, Jian; Qiu, Danqi; Zhu, Tianle

2018-04-01

Effects of carrier gas composition (N 2 /air) on NH 3 production, energy efficiency regarding NH 3 production and byproducts formation from plasma-catalytic decomposition of urea were systematically investigated using an Al 2 O 3 -packed dielectric barrier discharge (DBD) reactor at room temperature. Results show that the presence of O 2 in the carrier gas accelerates the conversion of urea but leads to less generation of NH 3 . The final yield of NH 3 in the gas phase decreased from 70.5%, 78.7%, 66.6% and 67.2% to 54.1%, 51.7%, 49.6% and 53.4% for applied voltages of 17, 19, 21 and 23kV, respectively when air was used as the carrier gas instead of N 2 . From the viewpoint of energy savings, however, air carrier gas is better than N 2 due to reduced energy consumption and increased energy efficiency for decomposition of a fixed amount of urea. Carrier gas composition has little influence on the major decomposition pathways of urea under the synergetic effects of plasma and Al 2 O 3 catalyst to give NH 3 and CO 2 as the main products. Compared to a small amount of N 2 O formed with N 2 as the carrier gas, however, more byproducts including N 2 O and NO 2 in the gas phase and NH 4 NO 3 in solid deposits were produced with air as the carrier gas, probably due to the unproductive consumption of NH 3 , the possible intermediate HNCO and even urea by the abundant active oxygen species and nitrogen oxides generated in air-DBD plasma. Copyright © 2017. Published by Elsevier B.V.

The behaviour of population in a plasma interacting with an atomic gas

International Nuclear Information System (INIS)

Furukane, Utaro; Oda, Toshiatsu.

1983-01-01

The processes leading to the population inversion are investigated in a recombining hydrogen plasma which is interacting with a cool and dense neutral hydrogen gas by using the rate equations on the basis of the CR model and the energy equation for electrons ions and neutral parlicles. The quasi-steady state approximation are used only for the levels higher than a certain level which is not the first excited level. The calculations have shown that the quasi-steady state cannot be realized while intense energy-flows due to the collisional processes exist between different kinds of the particles such as the electrons and the ions in the plasma and the population inversion is realized only in the quasi-steady state following the transient phase. The effects of the initial conditions of the hydrogen plasma and the introduced neutral hydrogen gas on the overpopulation density are also discussed. (author)

Binary-collision-approximation simulation for noble gas irradiation onto plasma facing materials

International Nuclear Information System (INIS)

Saito, Seiki; Nakamura, Hiroaki; Takayama, Arimichi; Ito, Atsushi M

2014-01-01

A number of experiments show that helium plasma constructs filament (fuzz) structures whose diameter is in nanometer-scale on the tungsten material under the suitable experimental condition. In this paper, binary-collision-approximation-based simulation is performed to reveal the mechanism and the conditions of fuzz formation of tungsten material under plasma irradiation. The irradiation of the plasma of hydrogen, deuterium, and tritium, and also the plasma of noble gas such as helium, neon, and argon atoms are investigated. The possibility of fuzz formation is discussed on the simulation result of penetration depth of the incident atoms

Hydrogen peroxide ingestion associated with portal venous gas and treatment with hyperbaric oxygen: a case series and review of the literature.

Science.gov (United States)

French, Loren Keith; Horowitz, B Zane; McKeown, Nathanael J

2010-07-01

Ingestion of concentrated hydrogen peroxide (H(2)O(2)) has been associated with venous and arterial gas embolic events, hemorrhagic gastritis, gastrointestinal bleeding, shock, and death. Although H(2)O(2) is generally considered a benign ingestion in low concentrations, case reports have described serious toxicity following high concentration exposures. Hyperbaric oxygen (HBO) has been used with success in managing patients suffering from gas embolism with and without manifestations of ischemia. Poison center records were searched from July 1999 to January 2010 for patients with H(2)O(2) exposure and HBO treatment. Cases were reviewed for the concentration of H(2)O(2), symptoms, CT scan findings of portal gas embolism, HBO treatment, and outcome. RESULTS; Eleven cases of portal gas embolism were found. Ages ranged from 4 to 89 years. All but one ingestion was accidental in nature. In 10 cases 35% H(2)O(2) was ingested and in 1 case 12% H(2)O(2) was ingested. All abdominal CT scans demonstrated portal venous gas embolism in all cases. Hyperbaric treatment was successful in completely resolving all portal venous gas bubbles in nine patients (80%) and nearly resolving them in two others. Ten patients were able to be discharged home within 1 day, and one patient had a 3.5-day length of stay. HBO was successful in resolving portal venous gas embolism from accidental concentrated H(2)O(2) ingestions.

Nanocomposite metal/plasma polymer films prepared by means of gas aggregation cluster source

Energy Technology Data Exchange (ETDEWEB)

Polonskyi, O.; Solar, P.; Kylian, O.; Drabik, M.; Artemenko, A.; Kousal, J.; Hanus, J.; Pesicka, J.; Matolinova, I. [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic); Kolibalova, E. [Tescan, Libusina trida 21, 632 00 Brno (Czech Republic); Slavinska, D. [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic); Biederman, H., E-mail: bieder@kmf.troja.mff.cuni.cz [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic)

2012-04-02

Nanocomposite metal/plasma polymer films have been prepared by simultaneous plasma polymerization using a mixture of Ar/n-hexane and metal cluster beams. A simple compact cluster gas aggregation source is described and characterized with emphasis on the determination of the amount of charged clusters and their size distribution. It is shown that the fraction of neutral, positively and negatively charged nanoclusters leaving the gas aggregation source is largely influenced by used operational conditions. In addition, it is demonstrated that a large portion of Ag clusters is positively charged, especially when higher currents are used for their production. Deposition of nanocomposite Ag/C:H plasma polymer films is described in detail by means of cluster gas aggregation source. Basic characterization of the films is performed using transmission electron microscopy, ultraviolet-visible and Fourier-transform infrared spectroscopies. It is shown that the morphology, structure and optical properties of such prepared nanocomposites differ significantly from the ones fabricated by means of magnetron sputtering of Ag target in Ar/n-hexane mixture.

Comparison of optical spectra recorded during DPF-1000U plasma experiments with gas-puffing

Directory of Open Access Journals (Sweden)

Zaloga Dobromil R.

2015-06-01

Full Text Available The results are presented of the optical spectra measurements for free plasma streams generated with the use of the modified DPF-1000U machine. This facility was recently equipped with a gas injection system (the so-called gas-puff placed on the symmetry axis behind the central opening in the inner electrode. The DPF-1000U experimental chamber was filled up with pure deuterium at the initial pressure of 1.6 or 2.4 mbar. Additionally, when the use was made of the gas-puff system about 1 cm3 of pure deuterium was injected at the pressure of 2 bars. The gas injection was initiated 1.5 or 2 ms before the triggering of the main discharge. The investigated plasma discharges were powered from a condenser bank charged initially to 23 kV (corresponding to the energy of 352 kJ, and the maximum discharge current amounted to about 1.8 MA. In order to investigate properties of a dense plasma column formed during DPF-1000U discharges the use was made of the optical emission spectroscopy. The optical spectra were recorded along the line of sight perpendicular to the vacuum chamber, using a Mechelle®900 spectrometer. The recent analysis of all the recorded spectra made it possible to compare the temporal changes in the electron density of a freely propagating plasma stream for discharges without and with the gas-puffing. Using this data an appropriate mode of operation of the DPF-1000U facility could be determined.

Absorption of the laser radiation by the laser plasma with gas microjet targets

Science.gov (United States)

Borisevichus, D. A.; Zabrodskii, V. V.; Kalmykov, S. G.; Sasin, M. E.; Seisyan, R. P.

2017-01-01

An upper limit of absorption of the laser radiation in the plasma produced in a gas jet Xe target with the average density of (3-6) × 1018 cm-3 and the effective diameter of 0.7 mm is found. It is equal to ≈50% and remains constant under any variation in this range of densities. This result contradicts both theoretical assessments that have predicted virtually complete absorption and results of earlier experiments with the laser spark in an unlimited stationary Xe gas with the same density, where the upper limit of absorption was close to 100%. An analysis shows that nonlinearity of absorption and plasma nonequilibrium lead to the reduction of the absorption coefficient that, along with the limited size of plasma, can explain the experimental results.

Numerical modeling of plasma plume evolution against ambient background gas in laser blow off experiments

International Nuclear Information System (INIS)

Patel, Bhavesh G.; Das, Amita; Kaw, Predhiman; Singh, Rajesh; Kumar, Ajai

2012-01-01

Two dimensional numerical modelling based on simplified hydrodynamic evolution for an expanding plasma plume (created by laser blow off) against an ambient background gas has been carried out. A comparison with experimental observations shows that these simulations capture most features of the plasma plume expansion. The plume location and other gross features are reproduced as per the experimental observation in quantitative detail. The plume shape evolution and its dependence on the ambient background gas are in good qualitative agreement with the experiment. This suggests that a simplified hydrodynamic expansion model is adequate for the description of plasma plume expansion.

Opportunities of influence of plasma streams formed in IKA with continuos nor king gas filling en the surface of materials

International Nuclear Information System (INIS)

Useinov, B.M.; Useinova, A.M.; Amrenova, A.U.; Pusankov, S.A.; Sartin, S.A.; Virko, P.G.

2001-01-01

The results of the investigation of influence of plasma stream formed in IKA with continuous working gas filling on the surface of stainless steel 12X18H10T and aluminum are given in this article. It is shown here that the effect of influence of plasma stream on the surface of materials depends on the way of working gas filling. There is the comparison of influence of plasma stream formed in plasma accelerator with impulse and continuous working gas filling

ESR spectra studies on polyterafluoroethyene films irradiated by radio frequency plasmas

International Nuclear Information System (INIS)

Ma Yuguang; Yang Meiling; Shen Jiacong; Lin Dehou

1991-01-01

The PTFE (polytetrafluoroethylene) films irradiated by Ar plasma were studied by using the method of ESR spectrometer. The peroxide free radicals were found on the surface of PTFE after plasma irradiation, which existed in the layer of some thickness of the surface. These free radicals were quite stable at room temperature. But when density of peroxide free radicals on the PTFE surface was big enough, termination reaction between the peroxide free radicals bound happen and endoperoxides were formed on the PTFE surface. Also the density of peroxide free radical decreased with increasing temperature and underwent a sudden change with temperature reaching 399 K- the glass transition temperature PTFE. The peroxide free radicals can be caught by free radical catcher PBN to form a stable free radical, also can react with MMA to form grafting layer

Enhancing gas-phase reaction in a plasma using high intensity and high power ultrasonic acoustic waves

DEFF Research Database (Denmark)

2010-01-01

is absorbed into said plasma (104), and where a sound pressure level of said generated ultrasonic high intensity and high power acoustic waves (102) is at least substantially 140 dB and where an acoustic power of said generated ultrasonic high intensity and high power acoustic waves (102); is at least...... substantially 100 W. In this way, a high sound intensity and power are obtained that efficiently enhances a gas-phase reaction in the plasma, which enhances the plasma process, e.g. enabling more efficient ozone or hydrogen generation using plasma in relation to reaction speed and/or obtained concentration......This invention relates to enhancing a gas-phase reaction in a plasma comprising: creating plasma (104) by at least one plasma source (106), and wherein that the method further comprises: generating ultrasonic high intensity and high power acoustic waves (102) having a predetermined amount...

Population inversion in a recombining hydrogen plasma interacting with a helium gas

International Nuclear Information System (INIS)

Oda, Toshiatsu; Furukane, Utaro.

1984-08-01

A numerical investigation has shown that the population inversion between the levels with the principal quantum number i=2 and 3 takes place in a recombining hydrogen plasma which is interacting with a cool and dense helium gas on the basis of a collisional- radiative (CR) model. Overpopulation density Δn 32 , which is defined as the difference between the population densities per unit statistical weight of the upper and lower excited levels 3 and 2, is found to be much higher than a threshold level for the laser oscillation in the quasi-steady state when the hydrogen plasma with nsub(e) = 10 13 --10 14 cm -3 interacts with the helium gas with pressure of --50 Torr. (author)

Tungsten oxide coatings deposited by plasma spray using powder and solution precursor for detection of nitrogen dioxide gas

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chao, E-mail: zhangc@yzu.edu.cn [College of Mechanical Engineering, Yangzhou University, Yangzhou 225127 (China); Wang, Jie [College of Mechanical Engineering, Yangzhou University, Yangzhou 225127 (China); Geng, Xin [College of Mechanical Engineering, Yangzhou University, Yangzhou 225127 (China); College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China)

2016-05-25

Increasing attention has been paid on preparation methods for resistive-type gas sensors based on semiconductor metal oxides. In this work, tungsten oxide (WO{sub 3}) coatings were prepared on alumina substrates and used as gas sensitive layers. The coatings were deposited by atmospheric plasma spray using powder, solution precursor, or a combination of both. Tungsten oxide powder through a powder port and ammonium tungstate aqueous solution through a liquid port were injected into plasma stream respectively or together to deposit WO{sub 3} coatings. Phase structures in the coatings were characterized by X-ray diffraction analyzer. The field-emission scanning electron microscopy images confirmed that the coatings were in microstructure, nanostructure or micro-nanostructure. The sensing properties of the sensors based on the coatings exposed to 1 ppm nitrogen dioxide gas were characterized in a home-made instrument. Sensing properties of the coatings were compared and discussed. The influences of gas humidity and working temperature on the sensor responses were further studied. - Highlights: • Porous gas sensitive coatings were deposited by plasma spray using powder and solution precursor. • Crystallized WO{sub 3} were obtained through hybrid plasma spray plus a pre-conditioned step. • Plasma power had an important influence on coating microstructure. • The particle size of atmospheric plasma-sprayed microstructured coating was stable. • Solution precursor plasma-sprayed WO{sub 3} coatings had nanostructure and showed good responses to 1 ppm NO{sub 2}.

Measurements of Plasma Expansion due to Background Gas in the Electron Diffusion Gauge Experiment

International Nuclear Information System (INIS)

Morrison, Kyle A.; Paul, Stephen F.; Davidson, Ronald C.

2003-01-01

The expansion of pure electron plasmas due to collisions with background neutral gas atoms in the Electron Diffusion Gauge (EDG) experiment device is observed. Measurements of plasma expansion with the new, phosphor-screen density diagnostic suggest that the expansion rates measured previously were observed during the plasma's relaxation to quasi-thermal-equilibrium, making it even more remarkable that they scale classically with pressure. Measurements of the on-axis, parallel plasma temperature evolution support the conclusion

Generation mechanism of hydrogen peroxide in dc plasma with a liquid electrode

Science.gov (United States)

Takeuchi, Nozomi; Ishibashi, Naoto

2018-04-01

The production mechanism of liquid-phase H2O2 in dc driven plasma in O2 and Ar with a water electrode was investigated. When a water anode was used, the concentration of H2O2 increased linearly with the treatment time. The production rate was proportional to the discharge current, and there was no dependence on the gap distance. On the other hand, the production rate was much smaller with a water anode. We concluded that the production of gas-phase H2O2 in the cathode sheath just above a water cathode and diffusion of this H2O2 into the water constitute the key mechanism in the production of liquid-phase H2O2.

Effects of Xe Gas Content and Total Gas Pressure on the Discharge Characteristics of Colour Plasma Display Panels

International Nuclear Information System (INIS)

Hu Wenbo; Han Mengju; Liang Zhihu

2006-01-01

The effects of the Xe gas content and total gas pressure on the discharge characteristics of colour plasma display panels including the sustaining voltage margin, white-field chromaticity, discharge time lag (DTL), discharge current peak, and full-width-at-half-maximum (FWHM) of the discharge current pulse, are experimentally studied. The results indicate that as the Xe gas content in the He-Ne-Xe gas mixture or total pressure increases, the sustaining voltage margin increases, the white-field chromaticity improves, and the discharge current peak has a maximum value, while DTL and FWHM have a minimum value. The mean electron energy in the gas mixture discharge is also calculated through a numerical solution of Boltzmann equation. The experimental results are explained from a view of the mean electron energy variations with the Xe gas content and total gas pressure

Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

OpenAIRE

Yurtisik,Koray; Tirkes,Suha; Dykhno,Igor; Gur,C. Hakan; Gurbuz,Riza

2013-01-01

Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex mi...

The free radical process for the polymer surface treated by radio frequency plasma

International Nuclear Information System (INIS)

Ma Yuguang; Yang Meiling; Shen Jiacong; Zheng Yingguang

1992-01-01

The formation and translation of the free radicals on the polymer surface treated by plasmas were studied and observed by ESR measurement. The results show that C-C bond split was main reaction in the process of the polymer irradiated by plasma, by which a stable alkyl free radical was formed. When alkyl free radical contacted with air, they translate into peroxide radical instantaneously. The peroxide radical was not as stable as radical in vacuum, they can react each other to form some polar-groups on polymer surface. The interaction between the peroxide free radical and polymer chain was correlative not only to the structure of polymer but also to the molecular motion of the polymer chain. The nature of plasma treating polymer surface was that the peroxide radicals were led onto polymer surface

Effect of neutral gas heating in argon radio frequency inductively coupled plasma

International Nuclear Information System (INIS)

Chin, O.H.; Jayapalan, K.K.; Wong, C.S.

2014-01-01

Heating of neutral gas in inductively coupled plasma (ICP) is known to result in neutral gas depletion. In this work, this effect is considered in the simulation of the magnetic field distribution of a 13.56 MHz planar coil ICP. Measured electron temperatures and densities at argon pressures of 0.03, 0.07 and 0.2 mbar were used in the simulation whilst neutral gas temperatures were heuristically fitted. The simulated results showed reasonable agreement with the measured magnetic field profile. (author)

Empirical evaluation of the radiative cooling coefficient for krypton gas in the FTU plasma

International Nuclear Information System (INIS)

Fournier, K.B.; Pacella, D.; Mazzitelli, G.; Stutman, D.; Soukanovskii, V.; Goldstein, W.H.

1997-01-01

For future fusion reactors, a careful balance must be achieved between the cooling of the outer plasma via impurity radiation and the deleterious effects of inevitable core penetration by impurity ions. We have injected krypton gas into the Frascati Tokamak Upgrade (FTU) plasma. The measured visible bremsstrahlung and bolometric signals from krypton have been inverted and the resulting radial impurity density profile and power loss profile for krypton gas are extracted. Using the measured electron density and temperature profiles, the radiative cooling coefficient for krypton is derived. The level of intrinsic impurities (Mo, Cr, Mn and Fe) in the plasma during the krypton puffing is monitored with a VUV SPRED spectrometer. Models for krypton emissivity from the literature are compared to our measured results. 7 figs

Proteins oxidation and autoantibodies' reactivity against hydrogen peroxide and malondialdehyde -oxidized thyroid antigens in patients' plasmas with Graves' disease and Hashimoto Thyroiditis.

Science.gov (United States)

Mseddi, Malek; Ben Mansour, Riadh; Gargouri, Bochra; Mnif, Fatma; El Ghawi, Samir; Hammami, Boutheina; Ghorbel, Abdelmonem; Abid, Mohamed; Lassoued, Saloua

2017-06-25

The aim of this study was to evaluate proteins oxidation in plasmas of two autoimmune thyroid diseases (AITD): Graves' disease (GD) and Hashimoto Thyroiditis (HT), and to determine whether oxidative modification of thyroid antigens (T.Ag) enhanced the reactivity of autoantibodies in plasmas of AITD patients compared with the reactivity towards native T.Ag. Carbonyl and thiol groups and MDA-protein adducts were assessed spectrophotometric methods in plasmas of 74 AITD patients and 65 healthy controls. The reactivities immunoglobulin (Ig)G autoantibodies towards malondialdéhyde (MDA)-modified T.Ag, hydrogen peroxide (H 2 O 2 )-modified T.Ag, native T.Ag and native derm were checked by enzyme-linked immunosorbent assay (ELISA). Evaluation of oxidized proteins exhibited high levels of MDA bound to proteins and carbonyl groups, as well as reduced thiol level in plasmas of AITD patients by comparison to healthy controls (p thyroid stimulating hormone level in HT patients in the other (r = 0.65, p < 0.001). The data suggest that high production of H 2 O 2 probably occurred during hormone synthesis could contribute to protein oxidation in AITD and to create neoepitopes responsible for autoantibody reactivity's to H 2 O 2 -oxidized T.Ag enhancement. These results provide support to the involvement of oxidative stress in AITD development and/or exacerbation. Copyright © 2017 Elsevier B.V. All rights reserved.

Radiation-induced lipid peroxidation, fish diet, and modulation of the effects by vitamin E

International Nuclear Information System (INIS)

Paranich, A.V.; Chajkina, L.A.; Zharkov, S.V.

1990-01-01

Data are presented in this paper on the effect of vitamin E on rats given a fish diet after whole-body gamma-irradiation. The content of lipid peroxidation products in rat plasma, brain and liver and also content of vitamin E have been investigated. Irradiation increases lipid peroxidation in the studied tissues and decreases vitamin E content. This process is aggravat ed by the fish diet. Vitamin E given in addition to fish diet helps the organism to stabilize the antioxidant homeostasis at a qualitatively different level

Production of uranium peroxide

International Nuclear Information System (INIS)

Caropreso, F.E.; Kreuz, D.F.

1977-01-01

A process is claimed of recovering uranium values as uranium peroxide from an aqueous uranyl solution containing dissolved vanadium and sodium impurities by treating the uranyl solution with hydrogen peroxide in an amount sufficient to have an excess of at least 0.5 parts H 2 O 2 per part of vanadium (V 2 O 5 ) above the stoichiometric amount required to form the uranium peroxide, the hydrogen peroxide treatment is carried out in three sequential phases consisting of I, a precipitation phase in which the hydrogen peroxide is added to the uranyl solution to precipitate the uranium peroxide and the pH of the reaction medium maintained in the range of 2.5 to 5.5 for a period of from about 1 to 60 minutes after the hydrogen peroxide addition; II, a digestion phase in which the pH of the reaction medium is maintained in the range of 3.0 to 7.0 for a period of about 5 to 180 minutes and III, a final phase in which the pH of the reaction medium is maintained in the range of 4.0 to 7.0 for a period of about 1 to 60 minutes during which time the uranium peroxide is separated from the reaction solution containing the dissolved vanadium and sodium impurities. The excess hydrogen peroxide is maintained during the entire treatment up until the uranium peroxide is separated from the reaction medium

Gas chromatography/plasma spectrometry - an important analytical tool for elemental speciation studies

International Nuclear Information System (INIS)

Wuilloud, Jorgelina C.A.; Wuilloud, Rodolfo G.; Vonderheide, Anne P.; Caruso, Joseph A.

2004-01-01

In this review, a full discussion and update of the state-of-the-art of gas chromatography (GC) coupled to all known plasma spectrometers is presented. A brief introductive discussion of the advantages and disadvantages of GC-plasma interfaces, as well as types of plasmas and mass spectrometers, is given. The plasma-based techniques covered include inductively coupled plasma mass spectrometry (ICP-MS) microwave-induced plasma optical emission spectrometry (MIP-OES), and inductively coupled plasma optical emission spectrometry (ICP-OES). Also, different variants of plasma sources, such as low power plasmas and glow discharge (GD) sources, are described and compared with respect to their capabilities in elemental speciation. Recent advances and alternative mass analyzers (collision/reaction cell; time-of-flight; double-focusing sector field) are also mentioned. Different aspects of the GC-plasma coupling are discussed with particular attention to the applications of these hyphenated techniques to the analysis of elemental species. Additionally, classical and modern sample preparation methods, including extraction and/or preconcentration and derivatization reactions, are presented and evaluated

Kinetics and hybrid kinetic-fluid models for nonequilibrium gas and plasmas

International Nuclear Information System (INIS)

Crouseilles, N.

2004-12-01

For a few decades, the application of the physics of plasmas has appeared in different fields like laser-matter interaction, astrophysics or thermonuclear fusion. In this thesis, we are interested in the modeling and the numerical study of nonequilibrium gas and plasmas. To describe such systems, two ways are usually used: the fluid description and the kinetic description. When we study a nonequilibrium system, fluid models are not sufficient and a kinetic description have to be used. However, solving a kinetic model requires the discretization of a large number of variables, which is quite expensive from a numerical point of view. The aim of this work is to propose a hybrid kinetic-fluid model thanks to a domain decomposition method in the velocity space. The derivation of the hybrid model is done in two different contexts: the rarefied gas context and the more complicated plasmas context. The derivation partly relies on Levermore's entropy minimization approach. The so-obtained model is then discretized and validated on various numerical test cases. In a second stage, a numerical study of a fully kinetic model is presented. A collisional plasma constituted of electrons and ions is considered through the Vlasov-Poisson-Fokker-Planck-Landau equation. Then, a numerical scheme which preserves total mass and total energy is presented. This discretization permits in particular a numerical study of the Landau damping. (author)

Calibration strategy for semi-quantitative direct gas analysis using inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Gerdes, Kirk; Carter, Kimberly E.

2011-01-01

A process is described by which an ICP-MS equipped with an Octopole Reaction System (ORS) is calibrated using liquid phase standards to facilitate direct analysis of gas phase samples. The instrument response to liquid phase standards is analyzed to produce empirical factors relating ion generation and transmission efficiencies to standard operating parameters. Empirical factors generated for liquid phase samples are then used to produce semi-quantitative analysis of both mixed liquid/gas samples and pure gas samples. The method developed is similar to the semi-quantitative analysis algorithms in the commercial software, which have here been expanded to include gas phase elements such as Xe and Kr. Equations for prediction of relative ionization efficiencies and isotopic transmission are developed for several combinations of plasma operating conditions, which allows adjustment of limited parameters between liquid and gas injection modes. In particular, the plasma temperature and electron density are calculated from comparison of experimental results to the predictions of the Saha equation. Comparisons between operating configurations are made to determine the robustness of the analysis to plasma conditions and instrument operating parameters. Using the methods described in this research, the elemental concentrations in a liquid standard containing 45 analytes and treated as an unknown sample were quantified accurately to ± 50% for most elements using 133 Cs as a single internal reference. The method is used to predict liquid phase mercury within 12% of the actual concentration and gas phase mercury within 28% of the actual concentration. The results verify that the calibration method facilitates accurate semi-quantitative, gas phase analysis of metal species with sufficient sensitivity to quantify metal concentrations lower than 1 ppb for many metallic analytes.

Laser ablated copper plasmas in liquid and gas ambient

Science.gov (United States)

Kumar, Bhupesh; Thareja, Raj K.

2013-05-01

The dynamics of copper ablated plasma plumes generated using laser ablation of copper targets in both liquid (de-ionized water) and gas (air) ambients is reported. Using time and space resolved visible emission spectroscopy (450-650 nm), the plasma plumes parameters are investigated. The electron density (ne) determined using Stark broadening of the Cu I (3d104d1 2D3/2-3d104p1 2P3/2 at 521.8 nm) line is estimated and compared for both plasma plumes. The electron temperature (Te) was estimated using the relative line emission intensities of the neutral copper transitions. Field emission scanning electron microscopy and energy dispersive x-ray spectral analysis of the ablated copper surface indicated abundance of spherical nanoparticles in liquid while those in air are amalgamates of irregular shapes. The nanoparticles suspended in the confining liquid form aggregates and exhibit a surface plasmon resonance at ˜590 nm.

Effect of gas pressure on active screen plasma nitriding response

International Nuclear Information System (INIS)

Nishimoto, Akio; Nagatsuka, Kimiaki; Narita, Ryota; Nii, Hiroaki; Akamatsu, Katsuya

2010-01-01

An austenitic stainless steel AISI 304 was active screen plasma nitrided using a 304 steel screen to investigate the effect of the gas pressure on the ASPN response. The sample was treated for 18 ks at 723 K in 25% N2 + 75% H2 gases. The gas pressure was changed to 100, 600 and 1200 Pa. The distance between screen and sample was also changed to 10, 30 and 50 mm. The nitrided samples were characterized by appearance observation, surface roughness, optical microscopy, X-ray diffraction, and microhardness testing. After nitriding, polygonal particles with a normal distribution were observed at the center and edges of all the ASPN-treated sample surfaces. Particles on the sample surfaces were finer with an increase in the gas pressure. The nitrided layer with a greater and homogeneous thickness was obtained at a low gas pressure of 100 Pa. (author)

Drinking orange juice increases total antioxidant status and decreases lipid peroxidation in adults.

Science.gov (United States)

Foroudi, Shahrzad; Potter, Andrew S; Stamatikos, Alexis; Patil, Bhimanagouda S; Deyhim, Farzad

2014-05-01

Cardiovascular disease (CVD) is the leading cause of death in the world and is the primary cause of mortality among Americans. One of the many reasons for the pathogenesis of CVD is attributed to eating diets high in saturated fat and refined carbohydrates and low in fruits and vegetables. Epidemiological evidence has supported a strong association between eating diets rich in fruits and vegetables and cardiovascular health. An experiment was conducted utilizing 24 adults with hypercholesterolemia and hypertriglyceridemia to evaluate the impact of drinking 20 fl oz of freshly squeezed orange juice daily for 90 days on blood pressure, lipid panels, plasma antioxidant capacity, metabolic hormones, lipid peroxidation, and inflammatory markers. Except for addition of drinking orange juice, subjects did not modify their eating habits. The findings suggested that drinking orange juice does not affect (P>.1) blood pressure, lipid panels, metabolic hormones, body fat percentage, or inflammatory markers. However, total plasma antioxidant capacity was significantly increased (Pjuice consumption. Drinking orange juice may protect the cardiovascular system by increasing total plasma antioxidant status and by lowering lipid peroxidation independent of other cardiovascular risk markers evaluated in this study.

Single-step generation of metal-plasma polymer multicore@shell nanoparticles from the gas phase.

Science.gov (United States)

Solař, Pavel; Polonskyi, Oleksandr; Olbricht, Ansgar; Hinz, Alexander; Shelemin, Artem; Kylián, Ondřej; Choukourov, Andrei; Faupel, Franz; Biederman, Hynek

2017-08-17

Nanoparticles composed of multiple silver cores and a plasma polymer shell (multicore@shell) were prepared in a single step with a gas aggregation cluster source operating with Ar/hexamethyldisiloxane mixtures and optionally oxygen. The size distribution of the metal inclusions as well as the chemical composition and the thickness of the shells were found to be controlled by the composition of the working gas mixture. Shell matrices ranging from organosilicon plasma polymer to nearly stoichiometric SiO 2 were obtained. The method allows facile fabrication of multicore@shell nanoparticles with tailored functional properties, as demonstrated here with the optical response.

Experimental and Numerical Study of the Effect of Gas-Shrouded Plasma Spraying on Cathode Coating of Alkaline Electrolysis Cells

Science.gov (United States)

Liu, T.; Reißner, R.; Schiller, G.; Ansar, A.

2018-01-01

The aim of this work is to improve the performance of electrodes prepared via atmospheric plasma spray by means of gas shrouding which is expected to apparently reduce the oxygen content of the plasma plume and subsequently improve the coating quality. Electrodes with dual-layer coating for alkaline water electrolysis were deposited on Ni-coated perforated substrates. Microstructure and morphology were studied by SEM. Element content was measured by EDS. Enthalpy probe was employed for measuring plasma temperature and velocity as well as the gas composition. For verifying and better understanding the shrouding effect numerical calculation was carried out according to the experimental settings. Electrochemical test was carried out to validate the shrouding effect. The results showed slight protecting effect of gas shrouding on plasma plume and the final coating. Over the dual-layer section, the measured oxygen fraction was 3.46 and 3.15% for the case without gas shrouding and with gas shrouding, respectively. With gas shrouding the coating exhibited similar element contents as the coating sprayed by VPS, while no obvious improvement was observed in the microstructure or the morphology. Evident electrochemical improvement was nevertheless achieved that with gas shrouding the electrode exhibited similar performance as that of the VPS-sprayed electrode.

Attenuation Effects of Plasma on Ka-Band Wave Propagation in Various Gas and Pressure Environments

Directory of Open Access Journals (Sweden)

Joo Hwan Lee

2018-01-01

Full Text Available This work demonstrates attenuation effects of plasma on waves propagating in the 26.5–40 GHz range. The effect is investigated via experiments measuring the transmission between two Ka-band horn antennas set 30 cm apart. A dielectric-barrier-discharge (DBD plasma generator with a size of 200 mm × 100 mm × 70 mm and consisting of 20 layers of electrodes is placed between the two antennas. The DBD generator is placed in a 400 mm × 300 mm × 400 mm acrylic chamber so that the experiments can be performed for plasma generated under various conditions of gas and pressure, for instance, in air, Ar, and He environments at 0.001, 0.05, and 1 atm of pressure. Attenuation is calculated by the difference in the transmission level, with and without plasma, which is generated with a bias voltage of 20 kV in the 0.1–1.4 kHz range. Results show that the attenuation varies from 0.05 dB/m to 9.0 dB/m depending on the environment. Noble gas environments show higher levels of attenuation than air, and He is lossier than Ar. In all gas environments, attenuation increases as pressure increases. Finally, electromagnetic models of plasmas generated in various conditions are provided.

Increased lipid peroxidation in pregnant women after iron and vitamin C supplementation.

Science.gov (United States)

Lachili, B; Hininger, I; Faure, H; Arnaud, J; Richard, M J; Favier, A; Roussel, A M

2001-11-01

Iron overload could promote the generation of free radicals and result in deleterious cellular damages. A physiological increase of oxidative stress has been observed in pregnancy. A routine iron supplement, especially a combined iron and vitamin C supplementation, without biological justifications (low hemoglobin [Hb] and iron stores) could therefore aggravate this oxidative risk. We investigated the effect of a daily combined iron supplementation (100 mg/d as fumarate) and vitamin C (500 mg/d as ascorbate) for the third trimester of pregnancy on lipid peroxidation (plasma TBARS), antioxidant micronutriments (Zn, Se, retinol, vitamin E, (beta-carotene) and antioxidant metalloenzymes (RBC Cu-Zn SOD and Se-GPX). The iron-supplemented group (n = 27) was compared to a control group (n = 27), age and number of pregnancies matched. At delivery, all the women exhibited normal Hb and ferritin values. In the supplemented group, plasma iron level was higher than in the control group (26.90 +/- 5.52 mmol/L) and TBARs plasma levels were significantly enhanced (p cell antioxidant metalloenzymes. Furthermore, the alpha-tocopherol plasma level was lowered in the iron-supplemented groups, suggesting an increased utilization of vitamin E. These data show that pharmalogical doses of iron, associated with high vitamin C intakes, can result in uncontrolled lipid peroxidation. This is predictive of adverse effects for the mother and the fetus. This study illustrates the potential harmful effects of iron supplementation when prescribed only on the assumption of anemia and not on the bases of biological criteria.

Role of lipid peroxidation and oxidative stress in 3-methylindole pneumotoxicity

International Nuclear Information System (INIS)

Cary, M.G.

1985-01-01

The cytochrome P-450-catalyzed metabolism of 3-methylindole (3-MI) results in acute lung injury in ruminants and horses. Experiments were conducted to determine the role of lipid peroxidation and oxidative stress in 3-MI pneumotoxicity in goats. Goats were given methylethylketone peroxide (MEKP), a potent peroxidant, 3-MI, indole, or cremophor-EL vehicle. The levels of shortchain hydrocarbons in expired air were measured for 6 hours post-dosing by gas chromatography. Exhaled hydrocarbons increased 20 to 30 fold within 1 hour in goats given MEKP. No significant changes were seen in goats given 3-Mi, indole or cremophor-EL. Levels of thiobarbituric acid-reactive substances, an indicator of lipid peroxidation, were significantly increased in lung tissue from goats given MEKP. In goats given 3-MI, indole or cremophor-EL, the levels were not significantly different from each other. Goats were killed at 6 hours post-dosing and examined post mortem. Bronchiolar epithelial necrosis was seen in goats given 3-MI but there were not lung lesions in other groups. The role of oxygen radicals in 3-MI pneumotoxicity was examined in a goat lung explant system using 51 Cr release as an indicator of cytotoxicity. The results of these studies provide no evidence to support the view that 3-MI pneumotoxicity involves lipid peroxidation or oxidative stress as a result of formation of oxygen or xenobiotic radicals

Stability aspects of plasmas penetrated by neutral gas with respect to velocity driven modes

International Nuclear Information System (INIS)

Ohlsson, D.

1978-08-01

A study of the stability properties of dense partially ionized plasmas immersed in strong magnetic fields with respect to velocity driven modes are presented. First we consider modes driven by mass motion perpendicular to the lines of force and the unperturbed density and temperature gradients. The presence of a third fluid, neutral gas, gives under certain conditions rise to unstable modes. This type of instability arises independently or whether the applied electric field transverse to the lines of force, driving the mass motion, being parallel or antiparallel to the unperturbed density and temperature gradient. The presence of neutral gas also corresponds to stabilizing effects which, in certain parameter regions, result in a quenching of this instability. It is shown that modes driven by velocity shear perpendicular to the lines of force are effectively stabilized by viscous and resistive effects. These effects are in certain parameter ranges strongly enhanced on account of plasma-neutral gas interaction effects. In collisionless plasmas, modes driven by velocity shear parallel to the lines of force are stabilized by compressibility effects parallel to the magnetic field and by finite Larmor radius effects. (author)

Contribution to the Chemistry of Plasma-Activated Water

Science.gov (United States)

Julák, J.; Hujacová, A.; Scholtz, V.; Khun, J.; Holada, K.

2018-01-01

Plasma-activated water (PAW) was prepared by exposure to nonthermal plasma produced by a positive dc corona discharge in a transient spark regime. The activation of water was performed in atmosphere of various surrounding gases (air, nitrogen, carbon dioxide, and argon). This PAW retains its biological activity, measured on the mouse neuroblastoma cells culture, even after storage for more than one year. The highest hydrogen peroxide content was found for PAWs prepared in the atmospheres of argon or carbon dioxide, whereas the PAWs prepared in air and nitrogen exhibited lower hydrogen peroxide content. The acidity of PAWs mediated by nitric and nitrous acid formation displayed an opposite trend. It is concluded that the long-lasting biological effect of PAW is mediated by hydrogen peroxide in acid milieu only, whereas other possible active components decompose rapidly.

Peroxide organometallic compounds and their transformations

International Nuclear Information System (INIS)

Razuvaev, G.A.; Brilkina, T.G.

1976-01-01

A survey is given experimental works on synthesis and reactions of peroxide organometallic compounds. Reactions have been considered of organometallic compounds with oxygen and organic peroxides which result in formation of both peroxide and non-peroxide products. Possible routes and mechanisms of chemical transformations of peroxide organometallic compounds have been discussed. Reactions of organometallic compounds with oxygen and peroxides have been considered

Effects of admixture gas on the production of {sup 18}F radioisotope in plasma focus devices

Energy Technology Data Exchange (ETDEWEB)

Talaei, Ahmad [Nuclear Science and Technology Research Institute (NSTR), Nuclear Science Research School, A.E.O.I., 14155-1339 Tehran (Iran, Islamic Republic of); Sadat Kiai, S.M., E-mail: sadatkiai@yahoo.co [Nuclear Science and Technology Research Institute (NSTR), Nuclear Science Research School, A.E.O.I., 14155-1339 Tehran (Iran, Islamic Republic of); Zaeem, A.A. [Department of Physics, Khaje Nasir University of Technology (K.N. Toosi), 1541846911 Tehran (Iran, Islamic Republic of)

2010-12-15

In this article, the effect of admixture gas on the heating and cooling of pinched plasma directly related to the enhancement or reduction of {sup 18}F production through the {sup 16}O({sup 3}He, p){sup 18}F is considered in the plasma focus devices. It is shown that by controlling the velocity of added Oxygen particles mixed with the working helium gas into the plasma focus chamber, one can increase the current and decrease the confinement time (plasma heating) or vice verse (plasma cooling). The highest level of nuclear activities of {sup 18}F was found around 16% of the Oxygen admixture participation and was about 0.35 MBq in the conditions of 20 kJ, 0.1 Hz and after 2 min operating of Dena PF. However, in the same condition, but for the frequency of 1 Hz, the level of activity increased up to 3.4 MBq.

Reinvestigation of the Henry's law constant for hydrogen peroxide with temperature and acidity variation.

Science.gov (United States)

Huang, Daoming; Chen, Zhongming

2010-01-01

Hydrogen peroxide is not only an important oxidant in itself; it also serves as both sink and temporary reservoir for other important oxidants including HOx (OH and HO2) radicals and O3 in the atmosphere. Its partitioning between gas and aqueous phases in the atmosphere, usually described by its Henry's law constant (K(H)), significantly influences its role in atmospheric processes. Large discrepancies between the K(H) values reported in previous work, however, have created uncertainty for atmospheric modelers. Based on our newly developed online instrumentation, we have re-determined the temperature and acidity dependence of K(H) for hydrogen peroxide at an air pressure of (0.960 +/- 0.013) atm (1 atm = 1.01325 x 10(5) Pa). The results indicated that the temperature dependence of K(H) for hydrogen peroxide fits to the Van't Hoff equation form, expressed as lnK(H) = a/T - b, and a = -deltaH/R, where K(H) is in M/atm (M is mol/L), T is in degrees Kelvin, R is the ideal gas constant, and deltaH is the standard heat of solution. For acidity dependence, results demonstrated that the K(H) value of hydrogen peroxide appeared to have no obvious dependence on decreasing pH level (from pH 7 to pH 1). Combining the dependence of both temperature and acidity, the obtained a and b were 7024 +/- 138 and 11.97 +/- 0.48, respectively, deltaH was (58.40 +/- 1.15) kJ/(K x mol), and the uncertainties represent sigma. Our determined K(H) values for hydrogen peroxide will therefore be of great use in atmospheric models.

Laser-produced dense plasma in extremely high pressure gas and its application to a plasma-bridged gap switch

International Nuclear Information System (INIS)

Yamada, J.; Okuda, A.

1989-01-01

When an extremely high pressure gas is irradiated by an intense laser light, a dense plasma produced at the focal spot moves towards the focusing lens with a high velocity. Making use of this phenomenon, a new plasma-bridged gap switch is proposed and its switching characteristics is experimentally examined. From the experiments, it is confirmed that the switching time is almost constant with the applied voltage only when the focal spot is just on the positive electrode, indicating that the bridging of gap is caused by the laser light. (author)

Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

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Koray Yurtisik

2013-09-01

Full Text Available Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex microstructure without compromising the welding efficiency. 11.1 mm-thick standard duplex stainless steel plates were joined in a single-pass using this novel technique. Same plates were also subjected to conventional gas metal arc and plasma arc welding processes, providing benchmarks for the investigation of the weldability of the material. In the first place, the hybrid welding process enabled us to achieve less heat input compared to gas metal arc welding. Consequently, the precipitation of secondary phases, which are known to be detrimental to the toughness and corrosion resistance of duplex stainless steels, was significantly suppressed in both fusion and heat affected zones. Secondly, contrary to other keyhole techniques, proper cooling time and weld metal chemistry were achieved during the process, facilitating sufficient reconstructive transformation of austenite in the ferrite phase.

Equivalent effect of neutral gas pressure and transverse magnetic field in low-pressure glow discharge plasma

International Nuclear Information System (INIS)

Toma, M.; Rusu, Ioana; Pohoata, V.; Mihaila, I.

2001-01-01

In the paper it is emphasized the equivalent effect of the neutral gas pressure and the action of a transverse magnetic field (TMF), respectively, on a striated positive plasma column. Experimental and theoretical results prove that the distance between striations has the same variation under the influence of both neutral gas pressure and the action of TMF. The pressure modification as well as the action of a TMF can induce ionization instability in the plasma column which explains the standing striation appearance. (authors)

Some aspects of the study of gas-discharge plasma and production of high magnetic fields

International Nuclear Information System (INIS)

Novitskii, V.G.

This collection is compiled from the papers presented in the section of MHD generators and superconducting devices at the Institute of Electromechanics Conference held in May 1965. The subjects discussed include three-phase plasmatrons, their operational characteristics, and the nature of the physical processes occurring in the arc chamber. The collection also contains the results of experimental and theoretical research on gas-discharge plasma, conduction phenomena in flowing gaseous plasmas, and energy balance and radiation in the case of gas-discharge plasma. It also considers the stability of arcs, the effect of the transverse magnetic field and gas flow on breakdown voltages, the electrode phenomena and the distribution of current on the electrodes. Results of research on the conditions of electric-arc contraction and the characteristics of a contracted arc are given. The problems associated with the production of high magnetic fields and the use of superconducting materials to this end are discussed. The experience gained in the design and fabrication of superconducting magnets and cryostats is described. The results of design calculations for magnetic systems of the Bitter type are also presented

Velocity limitations in coaxial plasma gun experiments with gas mixtures

International Nuclear Information System (INIS)

Axnaes, I.

1976-04-01

The velocity limitations found in many crossed field plasma experiments with neutral gas present are studied for binary mixtures of H 2 , He, N 2 O 2 , Ne and Ar. The apparatus used is a coaxial plasma gun with an azimuthal magnetic bias field. The discharge parameters are chosen so that the plasma is weakly ionized. In some of the mixtures it is found that one of the components tends to dominate in the sense that only a small amount (regarding volume) of that component is needed for the discharge to adopt a limiting velocity close to that for the pure component. Thus in a mixture between a heavy and a light component having nearly equal ionization potentials the heavy component dominates. Also if there is a considerable difference in ionization potential between the components, the component with the lowest ionization potential tends to dominate. (author)

Safe handling of potential peroxide forming compounds and their corresponding peroxide yielded derivatives.

Energy Technology Data Exchange (ETDEWEB)

Sears, Jeremiah Matthew; Boyle, Timothy J.; Dean, Christopher J.

2013-06-01

This report addresses recent developments concerning the identification and handling of potential peroxide forming (PPF) and peroxide yielded derivative (PYD) chemicals. PPF chemicals are described in terms of labeling, shelf lives, and safe handling requirements as required at SNL. The general peroxide chemistry concerning formation, prevention, and identification is cursorily presented to give some perspective to the generation of peroxides. The procedure for determining peroxide concentrations and the proper disposal methods established by the Hazardous Waste Handling Facility are also provided. Techniques such as neutralization and dilution are provided for the safe handling of any PYD chemicals to allow for safe handling. The appendices are a collection of all available SNL documentation pertaining to PPF/PYD chemicals to serve as a single reference.

Laser ablated copper plasmas in liquid and gas ambient

Energy Technology Data Exchange (ETDEWEB)

Kumar, Bhupesh; Thareja, Raj K. [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

2013-05-15

The dynamics of copper ablated plasma plumes generated using laser ablation of copper targets in both liquid (de-ionized water) and gas (air) ambients is reported. Using time and space resolved visible emission spectroscopy (450-650 nm), the plasma plumes parameters are investigated. The electron density (n{sub e}) determined using Stark broadening of the Cu I (3d{sup 10}4d{sup 1} {sup 2}D{sub 3/2}-3d{sup 10}4p{sup 1} {sup 2}P{sub 3/2} at 521.8 nm) line is estimated and compared for both plasma plumes. The electron temperature (T{sub e}) was estimated using the relative line emission intensities of the neutral copper transitions. Field emission scanning electron microscopy and energy dispersive x-ray spectral analysis of the ablated copper surface indicated abundance of spherical nanoparticles in liquid while those in air are amalgamates of irregular shapes. The nanoparticles suspended in the confining liquid form aggregates and exhibit a surface plasmon resonance at ∼590 nm.

Compression enhancement by current stepping in a multicascade liner gas-puff Z-pinch plasma

Energy Technology Data Exchange (ETDEWEB)

Khattak, N A D [Department of Physics, Gomal Unversity, D I Khan (Pakistan); Ahmad, Zahoor; Murtaza, G [National Tokamak Fusion Program, PAEC, Islamabad (Pakistan); Zakaullah, M [Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan)], E-mail: ktk_nad@yahoo.com

2008-04-15

Plasma dynamics of a liner consisting of two or three annular cascade gas-puffs with entrained axial magnetic field is studied using the modified snow-plow model. The current stepping technique (Les 1984 J. Phys. D: Appl. Phys. 17 733) is employed to enhance compression of the imploding plasma. A small-diameter low-voltage-driven system of imploding plasma is considered in order to work out the possibility of the highest gain, in terms of plasma parameters and radiation yield with a relatively simple and compact system. Our numerical results demonstrate that current stepping enhances the plasma compression, yielding high values of the plasma parameters and compressed magnetic field B{sub z} (in magnitudes), if the switching time for the additional current is properly synchronized.

Compression enhancement by current stepping in a multicascade liner gas-puff Z-pinch plasma

International Nuclear Information System (INIS)

Khattak, N A D; Ahmad, Zahoor; Murtaza, G; Zakaullah, M

2008-01-01

Plasma dynamics of a liner consisting of two or three annular cascade gas-puffs with entrained axial magnetic field is studied using the modified snow-plow model. The current stepping technique (Les 1984 J. Phys. D: Appl. Phys. 17 733) is employed to enhance compression of the imploding plasma. A small-diameter low-voltage-driven system of imploding plasma is considered in order to work out the possibility of the highest gain, in terms of plasma parameters and radiation yield with a relatively simple and compact system. Our numerical results demonstrate that current stepping enhances the plasma compression, yielding high values of the plasma parameters and compressed magnetic field B z (in magnitudes), if the switching time for the additional current is properly synchronized

Modeling and experiments on differential pumping in linear plasma generators operating at high gas flows

NARCIS (Netherlands)

Eck, van H.J.N.; Koppers, W.R.; Rooij, van G.J.; Goedheer, W.J.; Engeln, R.A.H.; Schram, D.C.; Lopes Cardozo, N.J.; Kleyn, A.W.

2009-01-01

The direct simulation Monte Carlo (DSMC) method was used to investigate the efficiency of differential pumping in linear plasma generators operating at high gas flows. Skimmers are used to separate the neutrals from the plasma beam, which is guided from the source to the target by a strong axial

Protective effect of ascorbic acid on netilmicin-induced lipid profile and peroxidation parameters in rabbit blood plasma.

Science.gov (United States)

Devbhuti, Pritesh; Sikdar, Debasis; Saha, Achintya; Sengupta, Chandana

2011-01-01

A drug may cause alteration in blood-lipid profile and induce lipid peroxidation phenomena on administration in the body. Antioxidant may play beneficial role to control the negative alteration in lipid profile and lipid peroxidation. In view of this context, the present in vivo study was carried out to evaluate the role of ascorbic acid as antioxidant on netilmicin-induced alteration of blood lipid profile and peroxidation parameters. Rabbits were used as experimental animals and blood was collected to estimate blood-lipid profiles, such as total cholesterol (TCh), high density lipoprotein cholesterol (HDL-Ch), low density lipoprotein cholesterol (LDL-Ch), very low density lipoprotein cholesterol (VLDL-Ch), triglycerides (Tg), phospholipids (PL), and total lipids (TL), as well as peroxidation parameters, such as malondialdehyde (MDA), 4-hydroxy-2-nonenal (HNE), reduced glutathione (GSH) and nitric oxide (NO). The results revealed that netilmicin caused significant enhancement of MDA, HNE, TCh, LDL-Ch, VLDL-Ch, Tg levels and reduction in GSH, NO, HDL-Ch, PL, TL levels. On co-administration, ascorbic acid was found to be effective in reducing netilmicin-induced negative alterations of the above parameters.

Effects of Acetate-Free Citrate Dialysate on Glycoxidation and Lipid Peroxidation Products in Hemodialysis Patients

Directory of Open Access Journals (Sweden)

Atsumi Masuda

2012-09-01

Full Text Available Background/Aims: Previous studies have shown the presence of high levels of glycoxidation and lipid peroxidation products in association with atherosclerosis in patients with end-stage kidney disease. Acetates are commonly used buffer for correcting metabolic acidosis in hemodialysis (HD patients. Since the toxic effects of acetates are well established, acetate-free citrate dialysate (AFD has become available in Japan. The objective of the present study was to evaluate the suppressive effects of AFD on oxidative stress in maintenance HD patients by measuring plasma pentosidine and malondialdehyde-modified low-density lipoprotein (MDA-LDL levels as markers for glycoxidation and lipid peroxidation products. Methods: Plasma pentosidine, MDA-LDL and other laboratory parameters were examined on maintenance HD at the Juntendo University Hospital before and after switching to AFD. Results: MDA-LDL levels divided by LDL cholesterol were significantly lower than those before switching to AFD. Furthermore, levels of plasma pentosidine were lower than those before switching to AFD. Stepwise multiple regression analysis revealed that the percent change of the calcium-phosphorus product in the nondiabetic group and that of phosphorus in the diabetic group were predictive variables for the percent change of MDA-LDL/LDL, whereas the percent change of log high-sensitive C-reactive protein and that of systolic blood pressure in the nondiabetic group and that of diastolic blood pressure in the diabetic group were predictive variables for the percent change of plasma pentosidine. Conclusions: It appears that AFD decreases glycoxidation and lipid peroxidation products when compared with acid citrate dextrose in HD patients. The reduction of oxidative stress by AFD during HD may have possible beneficial effects on atherosclerosis through calcium-phosphorus metabolism and blood pressure.

21 CFR 172.802 - Acetone peroxides.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acetone peroxides. 172.802 Section 172.802 Food and... Multipurpose Additives § 172.802 Acetone peroxides. The food additive acetone peroxides may be safely used in... acetone peroxide, with minor proportions of higher polymers, manufactured by reaction of hydrogen peroxide...

Using advanced oxidation treatment for biofilm inactivation by varying water vapor content in air plasma

Science.gov (United States)

Ryota, Suganuma; Koichi, Yasuoka

2015-09-01

Biofilms are caused by environmental degradation in food factories and medical facilities. The inactivation of biofilms involves making them react with chemicals including chlorine, hydrogen peroxide, and ozone, although inactivation using chemicals has a potential problem because of the hazardous properties of the residual substance and hydrogen peroxide, which have slow reaction velocity. We successfully performed an advanced oxidation process (AOP) using air plasma. Hydrogen peroxide and ozone, which were used for the formation of OH radicals in our experiment, were generated by varying the amount of water vapor supplied to the plasma. By varying the content of the water included in the air, the main product was changed from air plasma. When we increased the water content in the air, hydrogen peroxide was produced, while ozone peroxide was produced when we decreased the water content in the air. By varying the amount of water vapor, we realized a 99.9% reduction in the amount of bacteria in the biofilm when we discharged humidified air only. This work was supported by JSPS KAKENHI Grant Number 25630104.

The feed gas composition determines the degree of physical plasma-induced platelet activation for blood coagulation

Science.gov (United States)

Bekeschus, Sander; Brüggemeier, Janik; Hackbarth, Christine; Weltmann, Klaus-Dieter; von Woedtke, Thomas; Partecke, Lars-Ivo; van der Linde, Julia

2018-03-01

Cold atmospheric (physical) plasma has long been suggested to be a useful tool for blood coagulation. However, the clinical applicability of this approach has not been addressed sufficiently. We have previously demonstrated the ability of a clinically accepted atmospheric pressure argon plasma jet (kINPen® MED) to coagulate liver incisions in mice with similar performance compared to the gold standard electrocauterization. We could show that plasma-mediated blood coagulation was dependent on platelet activation. In the present work, we extended on this by investigating kINPen®-mediated platelet activation in anticoagulated human donor blood ex vivo. With focus on establishing high-throughput, multi-parametric platelet activation assays and performing argon feed gas parameter studies we achieved the following results: (i) plasma activated platelets in heparinized but not in EDTA-anticoagulated blood; (ii) plasma decreased total platelet counts but increased numbers of microparticles; (iii) plasma elevated the expression of several surface activation markers on platelets (CD62P, CD63, CD69, and CD41/61); (iv) in platelet activation, wet and dry argon plasma outperformed feed gas admixtures with oxygen and/or nitrogen; (v) plasma-mediated platelet activation was accompanied by platelet aggregation. Platelet aggregation is a necessary requirement for blood clot formation. These findings are important to further elucidate molecular details and clinical feasibility of cold physical plasma-mediated blood coagulation.

Pulsed-plasma gas-discharge inactivation of microbial pathogens in chilled poultry wash water.

Science.gov (United States)

Rowan, N J; Espie, S; Harrower, J; Anderson, J G; Marsili, L; MacGregor, S J

2007-12-01

A pulsed-plasma gas-discharge (PPGD) system was developed for the novel decontamination of chilled poultry wash water. Treatment of poultry wash water in the plasma generation chamber for up to 24 s at 4 degrees C reduced Escherichia coli NCTC 9001, Campylobacter jejuni ATCC 33560, Campylobacter coli ATCC 33559, Listeria monocytogenes NCTC 9863, Salmonella enterica serovar Enteritidis ATCC 4931, and S. enterica serovar Typhimurium ATCC 14028 populations to non-detectable levels ( or = 3 log CFU/ml) in recalcitrant B. cereus NCTC 11145 endospore numbers within 30 s, the level of endospore reduction was dependent on the nature of the sparged gas used in the plasma treatments. Scanning electron microscopy revealed that significant damage occurred at the cellular level in PPGD-treated test organisms. This electrotechnology delivers energy in intense ultrashort bursts, generating products such as ozone, UV light, acoustic and shock waves, and pulsed electric fields that have multiple bactericidal properties. This technology offers an exciting complementary or alternative approach for treating raw poultry wash water and for preventing cross-contamination in processing environments.

Terahertz-Radiation-Enhanced Emission of Fluorescence from Gas Plasma

International Nuclear Information System (INIS)

Liu Jingle; Zhang, X.-C.

2009-01-01

We report the study of femtosecond laser-induced air plasma fluorescence under the illumination of terahertz (THz) pulses. Semiclassical modeling and experimental verification indicate that time-resolved THz radiation-enhanced emission of fluorescence is dominated by the electron kinetics and the electron-impact excitation of gas molecules or ions. We demonstrate that the temporal waveform of the THz field could be retrieved from the transient enhanced fluorescence, making omnidirectional, coherent detection available for THz time-domain spectroscopy.

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

Directory of Open Access Journals (Sweden)

Valery A. Tutyk

2013-01-01

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

Current distribution measurements inside an electromagnetic plasma gun operated in a gas-puff mode.

Science.gov (United States)

Poehlmann, Flavio R; Cappelli, Mark A; Rieker, Gregory B

2010-12-01

Measurements are presented of the time-dependent current distribution inside a coaxial electromagnetic plasma gun. The measurements are carried out using an array of six axially distributed dual-Rogowski coils in a balanced circuit configuration. The radial current distributions indicate that operation in the gas-puff mode, i.e., the mode in which the electrode voltage is applied before injection of the gas, results in a stationary ionization front consistent with the presence of a plasma deflagration. The effects of varying the bank capacitance, transmission line inductance, and applied electrode voltage were studied over the range from 14 to 112 μF, 50 to 200 nH, and 1 to 3 kV, respectively.

Characterization of the gas-puff imploding plasma on the NRL Gamble II generator

International Nuclear Information System (INIS)

Stephanakis, S.J.; Boller, J.R.; Cooperstein, G.

1984-01-01

Recently, an experimental and theoretical effort has been undertaken at NRL aimed at contributing to understanding the physics of the implosion dynamics and of the resulting highly localized plasma pinch in such experiments. Supersonic nozzles producing a cylindrical gas flow provide the load for the Gamble II generator operating at the 1.5 TW level. The gas jet is preionized and then imploded to the axis by the machine electrical pulse in a very short time scale. During the implosion process, the attained kinetic energy is efficiently converted to plasma thermal energy and produces the desired radiation. Preliminary experimental results are presented from the study of the conditions necessary in order to efficiently couple such loads to the Gamble II generator. These results are correlated to existing scaling laws and are compared with theoretical models

Extractive alkylation of 6-mercaptopurine and determination in plasma by gas chromatography-mass spectrometry.

Science.gov (United States)

Floberg, S; Hartvig, P; Lindström, B; Lönner-Holm, G; Odlind, B

1981-09-11

An analytical procedure was developed for the determination of 6-mercaptopurine in plasma. Owing to the polar character and low plasma concentration of the compound, extraction and derivatization was carried out directly from the plasma sample by extractive alkylation. Determination was made using gas chromatography-mass spectrometry with multiple-ion detection. Conditions with respect to the rate of formation and the stability of the derivative formed in the extractive alkylation step were evaluated. The selectively of the method to azathioprine and to metabolites was thoroughly investigated. No 6-mercaptopurine was formed from azathioprine added to water or plasma and run through the method. The method enables the detection of 2 ng of 6 mercaptopurine in a 1.0-ml plasma sample. Quantitative determinations were done down to 10 ng/ml 6 mercaptopurine in plasma.

Hydrogen peroxide kinetics in water radiolysis

Science.gov (United States)

Iwamatsu, Kazuhiro; Sundin, Sara; LaVerne, Jay A.

2018-04-01

The kinetics of the formation and reaction of hydrogen peroxide in the long time γ- radiolysis of water is examined using a combination of experiment with model calculations. Escape yields of hydrogen peroxide on the microsecond time scale are easily measured with added radical scavengers even with substantial amounts of initial added hydrogen peroxide. The γ-radiolysis of aqueous hydrogen peroxide solutions without added radical scavengers reach a steady state limiting concentration of hydrogen peroxide with increasing dose, and that limit is directly proportional to the initial concentration of added hydrogen peroxide. The dose necessary to reach that limiting hydrogen peroxide concentration is also proportional to the initial concentration, but dose rate has a very small effect. The addition of molecular hydrogen to aqueous solutions of hydrogen peroxide leads to a decrease in the high dose limiting hydrogen peroxide concentration that is linear with the initial hydrogen concentration, but the amount of decrease is not stoichiometric. Proton irradiations of solutions with added hydrogen peroxide and hydrogen are more difficult to predict because of the decreased yields of radicals; however, with a substantial increase in dose rate there is a sufficient decrease in radical yields that hydrogen addition has little effect on hydrogen peroxide decay.

Surface modification of cotton fabrics by gas plasmas for color strength and adhesion by inkjet ink printing

International Nuclear Information System (INIS)

Pransilp, Porntapin; Pruettiphap, Meshaya; Bhanthumnavin, Worawan; Paosawatyanyong, Boonchoat; Kiatkamjornwong, Suda

2016-01-01

Graphical abstract: - Highlights: • Both O_2 and N_2 plasma increased cotton surface wettability and higher K/S. • SF6 plasma gave hydrophobicity on cotton surface and increased contact angle to 138°. • Plasma treatment on cotton fabric produced surface roughness. • XPS confirmed the generation of new functional groups on cotton fabric. • Wettability and surface roughness controlled K/S and good ink adhesion. - Abstract: Surface properties of cotton fabric were modified by three types of gas plasma pretreatment, namely, oxygen (O_2), nitrogen (N_2) and sulfur hexafluoride (SF_6), to improve ink absorption of water-based pigmented inkjet inks and color reproduction of the treated surfaces. Effects of gas plasma exposure parameters of power, exposure time and gas pressure on surface physical and chemical properties of the treated fabrics were investigated. XPS (X-ray photoelectron spectroscopy) was used to identify changes in functional groups on the fabric surface while AFM (atomic force microscopy) and SEM (scanning electron microscopy) were used to reveal surface topography of the fabric. Color spectroscopic technique was used to investigate changes in color strength caused by different absorptions of the printed fabrics. The O_2 plasma treatments produced new functional groups, −O−C−O/C=O and O−C=O while N_2 plasma treatments produced additionally new functional groups, C−N and O=C−NH, onto the fabric surface which increased hydrophilic properties and surface energy of the fabric. For cotton fabric treated with SF_6 plasma, the fluorine functionalization was additionally found on the surface. Color strength values (K/S) increased when compared with those of the untreated fabrics. SF_6 plasma-treated fabrics were hydrophobic and caused less ink absorption. Fabric surface roughness caused by plasma etching increased fabric surface areas, captured more ink, and enhanced a larger ink color gamut and ink adhesion. Cotton fabrics exhibited higher

Experimental Evaluation of SI Engine Operation Supplemented by Hydrogen Rich Gas from a Compact Plasma Boosted Reformer

International Nuclear Information System (INIS)

J. B. Green, Jr.; N. Domingo; J. M. E. Storey; R.M. Wagner; J.S. Armfield; L. Bromberg; D. R. Cohn; A. Rabinovich; N. Alexeev

2000-01-01

It is well known that hydrogen addition to spark-ignited (SI) engines can reduce exhaust emissions and increase efficiency. Micro plasmatron fuel converters can be used for onboard generation of hydrogen-rich gas by partial oxidation of a wide range of fuels. These plasma-boosted microreformers are compact, rugged, and provide rapid response. With hydrogen supplement to the main fuel, SI engines can run very lean resulting in a large reduction in nitrogen oxides (NO x ) emissions relative to stoichiometric combustion without a catalytic converter. This paper presents experimental results from a microplasmatron fuel converter operating under variable oxygen to carbon ratios. Tests have also been carried out to evaluate the effect of the addition of a microplasmatron fuel converter generated gas in a 1995 2.3-L four-cylinder SI production engine. The tests were performed with and without hydrogen-rich gas produced by the plasma boosted fuel converter with gasoline. A one hundred fold reduction in NO x due to very lean operation was obtained under certain conditions. An advantage of onboard plasma-boosted generation of hydrogen-rich gas is that it is used only when required and can be readily turned on and off. Substantial NO x reduction should also be obtainable by heavy exhaust gas recirculation (EGR) facilitated by use of hydrogen-rich gas with stoichiometric operation

NH3/O2 mixed gas plasmas alter the interaction of blood components with stainless steel.

Science.gov (United States)

Chen, Meng; Zamora, Paul O; Peña, Louis; Som, Prantika; Osaki, Shigemasa

2003-12-01

Stainless steel treated with a mixed gas plasma of NH(3) plus O(2) had chemical and biologic characteristics distinct from untreated stainless steel or stainless steel treated with NH(3) or O(2) plasmas used separately. NH(3)/O(2) plasmas deposited nitrogen as both -CN (organic) and -NO (nitrate, nitrite)--materials not found on untreated stainless steel--and the contact angle changed from 44 degrees to 23 degrees. Treatment of stainless steel (and titanium) resulted in surfaces with enhanced resistance to platelet and leukocyte attachment. A gas plasma of N(2)O/O(2) also was found to reduce platelet and leukocyte attachment, suggesting that these properties may be common to surfaces coated with oxynitrites (nitrides). Upon subcutaneous implantation, no inflammation, hemolysis, or untoward thrombosis was noted in the tissue surrounding the wafers treated with the NH(3)/O(2) plasmas, although the cellular density was considerably reduced by 2 weeks after implant. Collectively, the results suggest that NH(3)/O(2) plasmas impart a unique character to stainless steel that may be useful in the construction of medical devices. Copyright 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 994-1000, 2003

Aqueous-phase chemistry and bactericidal effects from an air discharge plasma in contact with water: Evidence for the formation of peroxynitrite through a pseudo-second-order post-discharge reaction of H2O2 and HNO2

Czech Academy of Sciences Publication Activity Database

Lukeš, Petr; Doležalová, Eva; Sisrová, Irena; Člupek, Martin

2014-01-01

Roč. 23, č. 1 (2014), 015019-015019 ISSN 0963-0252 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100431203 Program:M Institutional support: RVO:61389021 Keywords : air discharge plasma * plasma–liquid interactions * peroxynitrite * hydrogen peroxide * phenol * bacteria Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.591, year: 2014 http://iopscience.iop.org/0963-0252/23/1/015019/pdf/0963-0252_23_1_015019.pdf

Abatement of global warming gas emissions from semiconductor manufacturing processes by non-thermal plasma-catalyst systems

International Nuclear Information System (INIS)

Chang, J-S.; Urashima, K.

2009-01-01

Emission of various hazardous air pollutants (HAPs) and greenhouse gases including perfluoro-compounds (PFCs) from semiconductor industries may cause significant impact on human health and the global environment, has attracted much public attention. In this paper, an application of nonthermal plasma-adsorbent system for a removal of PFCs emission from semiconductor process flue gases is experimentally investigated. The non-thermal plasma reactor used is the ferro-electric packed-bed type barrier discharge plasma and adsorbent reactor used is Zeolite bed reactor. The results show that for a simulated semiconductor process flue gas with C 2 F 6 (2000ppm)/ CF 4 (1000ppm)/ N 2 O(1000ppm)/ N 2 / Air mixture, 54% of C 2 F 6 and 32% of CF 4 were decomposed by the plasma reactor and 100% of C 2 F 6 and 98% of CF 4 were removed by plasma reactor/Zeolite adsorbent hybrid system. For a simulated semiconductor process flue gas with NF 3 (2000ppm)/ SiF 4 (1000ppm)/ N 2 O(200ppm)/ N 2 / Air mixture, 92% of NF 3 and 32% of SiF 4 were decomposed by the plasma reactor and total (100%) removal of the pollutant gases was achieved by plasma reactor/Zeolite adsorbent hybrid system. (author)

Yield of Ozone, Nitrite Nitrogen and Hydrogen Peroxide Versus Discharge Parameter Using APPJ Under Water

International Nuclear Information System (INIS)

Chen Bingyan; Wen Wen; Zhu Changping; Wang Yuan; Gao Ying; Fei Juntao; He Xiang; Yin Cheng; Jiang Yongfeng; Chen Longwei

2016-01-01

Discharge plasma in and in contact with water can be accompanied with ultraviolet radiation and electron impact, thus can generate hydroxyl radicals, ozone, nitrite nitrogen and hydrogen peroxide. In this paper, a non-equilibrium plasma processing system was established by means of an atmospheric pressure plasma jet immersed in water. The hydroxyl intensities and discharge energy waveforms were tested. The results show that the positive and negative discharge energy peaks were asymmetric, where the positive discharge energy peak was greater than the negative one. Meanwhile, the yield of ozone and nitrite nitrogen was enhanced with the increase of both the treatment time and the discharge energy. Moreover, the pH value of treated water was reduced rapidly and maintained at a lower level. The residual concentration of hydrogen peroxide in APPJ treated water was kept at a low level. Additionally, both the efficiency energy ratio of the yield of ozone and nitrite nitrogen and that of the removal of p-nitrophenol increased as a function of discharge energy and discharge voltage. The experimental results were fully analyzed and the chemical reaction equations and the physical processes of discharges in water were given. (paper)

Characteristics of x-ray radiation from a gas-puff z-pinch plasma

International Nuclear Information System (INIS)

Akiyama, N.; Takasugi, K.

2002-01-01

Characteristics of x-ray radiation from Ar gas-puff z-pinch plasma have been investigated by changing delay time of discharge from gas puffing. Intense cloud structure of x-ray image was observed at small delay time region, but the total x-ray signal was not so intense. The x-ray signal increased with increasing the delay time, and hot spots of x-ray image also became intense. Electron temperature was evaluated from x-ray spectroscopic data, and no significant difference in temperature was observed. (author)

First in situ plasma and neutral gas measurements at comet Halley: initial VEGA results

International Nuclear Information System (INIS)

Gringauz, K.I.; Remizov, A.P.; Gombosi, T.I.

1986-04-01

The first in situ observations and a description of the large scale behaviour of comet Halley's plasma environment are presented. The scientific objectives of the PLASMAG-1 experiment were as follows: to study the change of plasma parameters and distributions as a function of cometocentric distance; to investigate the existence and structure of the cometary bow shock; to determine the change in chemical composition of the heavily mass loaded plasma as the spacecraft approached the comet; and to measure the neutral gas distribution along the spacecraft trajectory. (author)

Plasma lipid peroxidation, blood GSH concentration and erythrocyte antioxidant enzymes in menstruating females with ovulatory and anovulatory cycles compared with males

Directory of Open Access Journals (Sweden)

G Lutosławska

2003-12-01

Full Text Available This study was undertaken to evaluate plasma TBARS and blood GSH concentration and erythrocyte antioxidant enzymes (glutathione peroxidase, catalase and superoxide dismutase in active, regularly menstruating female physical education students with ovulatory and anovulatory menstrual cycles and in their male counterparts. A total of 27 subjects (12 males and 15 females volunteered to participate in the study. All females were regularly menstruating with cycle length between 26-31 days. Plasma progesterone and 17-β-estradiol concentrations were assayed during the 7th-9th and 22nd-25th day of the menstrual cycle. Women with plasma progesterone concentration exceeding 19 nmol•l-1 during the 22nd-25th day were referred to as ovulatory (Group OV; n=7. Women without a peak plasma progesterone concentration were referred to as anovulatory (Group AN; n=8. Blood from male subjects was withdrawn twice - two weeks apart, at their convenience. It was found that the menstrual cycle phases did not affect plasma TBARS and blood glutathione concentration and erythrocyte GPX, CAT and SOD activity. However, erythrocyte GPX activity either in ovulatory or anovulatory women was by about 30% higher than in male subjects. Erythrocyte SOD activity in ovulatory women both in follicular and luteal phase of the menstrual cycle (1557 U/g Hb and 1394.6 U/g Hb, respectively was markedly lower than in men (1951.8 and 1937.7 U/g Hb for blood sampling I and II, respectively. In contrast, erythrocyte SOD activity in anovulatory women (1855.5 U/g Hb and 1745.7 U/g Hb in the follicular and luteal phases, respectively was similar to that found in men. The above data indicated that erythrocyte GPX and SOD activities are sensitive to plasma ovarian hormone concentration. In addition, they suggested that due to higher erythrocyte GPX activity females even with anovulatory menstrual cycles are protected better than males against hydrogen peroxide action. However, lower superoxide

Study of carbon dioxide gas treatment based on equations of kinetics in plasma discharge reactor

Science.gov (United States)

Abedi-Varaki, Mehdi

2017-08-01

Carbon dioxide (CO2) as the primary greenhouse gas, is the main pollutant that is warming earth. CO2 is widely emitted through the cars, planes, power plants and other human activities that involve the burning of fossil fuels (coal, natural gas and oil). Thus, there is a need to develop some method to reduce CO2 emission. To this end, this study investigates the behavior of CO2 in dielectric barrier discharge (DBD) plasma reactor. The behavior of different species and their reaction rates are studied using a zero-dimensional model based on equations of kinetics inside plasma reactor. The results show that the plasma reactor has an effective reduction on the CO2 density inside the reactor. As a result of reduction in the temporal variations of reaction rate, the speed of chemical reactions for CO2 decreases and very low concentration of CO2 molecules inside the plasma reactor is generated. The obtained results are compared with the existing experimental and simulation findings in the literature.

Porous layered double hydroxides synthesized using oxygen generated by decomposition of hydrogen peroxide

NARCIS (Netherlands)

Gonzalez Rodriguez, P.; de Ruiter, M.P.; Wijnands, Tom; ten Elshof, Johan E.

2017-01-01

Porous magnesium-aluminium layered double hydroxides (LDH) were prepared through intercalation and decomposition of hydrogen peroxide (H2O2). This process generates oxygen gas nano-bubbles that pierce holes in the layered structure of the material by local pressure build-up. The decomposition of the

Pyrolysis/gasification of biomass for synthetic fuel production using a hybrid gas- water stabilized plasma torch

Czech Academy of Sciences Publication Activity Database

Van Oost, G.; Hrabovský, Milan; Kopecký, Vladimír; Konrád, Miloš; Hlína, Michal; Kavka, Tetyana; Beeckman, E.; Verstraeten, J.

2007-01-01

Roč. 6, č. 1 (2007), s. 9-12. ISBN 978-4-9900642-5-9 R&D Projects: GA ČR GA202/05/0669 Institutional research plan: CEZ:AV0Z20430508 Keywords : Thermal plasma * pyrolysis * biomass gasification Subject RIV: BL - Plasma and Gas Discharge Physics

Positive-column plasma studied by fast-flow glow discharge mass spectrometry: Could it be a 'Rydberg gas?'

International Nuclear Information System (INIS)

Mason, Rod S.; Miller, Pat D.; Mortimer, Ifor; Mitchell, David J.; Dash, Neil A.

2003-01-01

Ions created from the fast-flowing positive column plasma of a glow discharge were monitored using a high voltage magnetic sector mass spectrometer. Since the field gradient and sheath potentials created by the plasma inside the source opposed cation transfer, it is inferred that the ions detected were the field-ionized Rydberg species. This is supported by the mass spectral changes which occurred when a negative bias was applied to the sampling aperture and by the contrasting behavior when attached to a quadrupole analyzer. Reaction with H 2 (titrated into the flowing plasma) quenched not only the ionization of discharge gas Rydberg atoms but also the passage of electric current through the plasma, without significant changes to the field and sheath potentials. Few 'free' ions were present and the lifetimes of the Rydberg atoms detected were much longer than seen in lower pressure experiments, indicating additional stabilization in the plasma environment. The observations support the model of the flowing plasma, given previously [R. S. Mason, P. D. Miller, and I. P. Mortimer, Phys. Rev. E 55, 7462 (1997)] as mainly a neutral Rydberg atom gas, rather than a conventional ion-electron plasma

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.

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

Ionized gas (plasma) delivery of reactive oxygen species (ROS) into artificial cells

International Nuclear Information System (INIS)

Hong, Sung-Ha; Jenkins, A Toby A; Szili, Endre J; Short, Robert D

2014-01-01

This study was designed to enhance our understanding of how reactive oxygen species (ROS), generated ex situ by ionized gas (plasma), can affect the regulation of signalling processes within cells. A model system, comprising of a suspension of phospholipid vesicles (cell mimics) encapsulating a ROS reporter, was developed to study the plasma delivery of ROS into cells. For the first time it was shown that plasma unequivocally delivers ROS into cells over a sustained period and without compromising cell membrane integrity. An important consideration in cell and biological assays is the presence of serum, which significantly reduced the transfer efficiency of ROS into the vesicles. These results are key to understanding how plasma treatments can be tailored for specific medical or biotechnology applications. Further, the phospholipid vesicle ROS reporter system may find use in other studies involving the application of free radicals in biology and medicine. (fast track communication)

Ionized gas (plasma) delivery of reactive oxygen species (ROS) into artificial cells

Science.gov (United States)

Hong, Sung-Ha; Szili, Endre J.; Jenkins, A. Toby A.; Short, Robert D.

2014-09-01

This study was designed to enhance our understanding of how reactive oxygen species (ROS), generated ex situ by ionized gas (plasma), can affect the regulation of signalling processes within cells. A model system, comprising of a suspension of phospholipid vesicles (cell mimics) encapsulating a ROS reporter, was developed to study the plasma delivery of ROS into cells. For the first time it was shown that plasma unequivocally delivers ROS into cells over a sustained period and without compromising cell membrane integrity. An important consideration in cell and biological assays is the presence of serum, which significantly reduced the transfer efficiency of ROS into the vesicles. These results are key to understanding how plasma treatments can be tailored for specific medical or biotechnology applications. Further, the phospholipid vesicle ROS reporter system may find use in other studies involving the application of free radicals in biology and medicine.

Resonance-enhanced laser-induced plasma spectroscopy: ambient gas effects

International Nuclear Information System (INIS)

Lui, S.L.; Cheung, N.H.

2003-01-01

When performing laser-induced plasma spectroscopy for elemental analysis, the sensitivity could be significantly enhanced if the plume was resonantly rekindled by a dye laser pulse. The extent of the enhancement was found to depend on the ambient gas. Air, nitrogen, helium, argon and xenon at pressures ranging from vacuum to 1 bar were investigated. In vacuum, the analyte signal was boosted because of reduced cooling, but it soon decayed as the plume freely expanded. By choosing the right ambient gas at the right pressure, the expanding plume could be confined as well as thermally insulated to maximize the analyte signal. For instance, an ambient of 13 mbar xenon yielded a signal-to-noise ratio of 110. That ratio was 53 when the pellet was ablated in air, and decreased further to 5 if the dye laser was tuned off resonance

Soliton-plasma nonlinear dynamics in mid-IR gas-filled hollow-core fibers

DEFF Research Database (Denmark)

Habib, Selim; Markos, Christos; Bang, Ole

2017-01-01

We investigate numerically soliton-plasma interaction in a noble-gas-filled silica hollow-core anti-resonant fiber pumped in the mid-IR at 3.0 mu m. We observe multiple soliton self-compression stages due to distinct stages where either the self-focusing or the self-defocusing nonlinearity...

Analysis of noble gas recycling at a fusion plasma divertor

International Nuclear Information System (INIS)

Brooks, J.N.

1996-01-01

Near-surface recycling of neon and argon atoms and ions at a divertor has been studied using impurity transport and surface interaction codes. A fixed background deuterium endash tritium plasma model is used corresponding to the International Thermonuclear Experimental Reactor (ITER) [ITER EDA Agreement and Protocol 2, ITER EDA Documentation Series No. 5 (International Atomic Energy Agency, Vienna, 1994)] radiative plasma conditions (T e ≤10 eV). The noble gas transport depends critically on the divertor surface material. For low-Z materials (Be and C) both neon and argon recycle many (e.g., ∼100) times before leaving the near-surface region. This is also true for an argon on tungsten combination. For neon on tungsten, however, there is low recycling. These variations are due to differences in particle and energy reflection coefficients, mass, and ionization rates. In some cases a high flux of recycling atoms is ionized within the magnetic sheath and this can change local sheath parameters. Due to inhibited backflow, high recycling, and possibly high sputtering, noble gas seeding (for purposes of enhancing radiation) may be incompatible with Be or C surfaces, for fusion reactor conditions. On the other hand, neon use appears compatible with tungsten. copyright 1996 American Institute of Physics

Role of O radical on the formation of O{sub 2} gas plasma; O{sub 2} purazuma ni okeru O rajikaru no yakuwari

Energy Technology Data Exchange (ETDEWEB)

Matsui, I. [Toshiba Reasearch and Development Ceter, Tokyo (Japan). Mechanical Systems Laboratory

2000-11-10

The effect of plasma formed gas on the plasma structure is investigated using a self consistent continuous fluid plasma model, which assumes that the local field approximation was attained in the RF plasma. The swarm parameter was obtained by Boltzmann analysis for O{sub 2} gas which contains various amounts of O radicals. Positive ion density, negative ion density, and electron density in the O{sub 2} RF plasma including O radical generation were calculated by self-consistent one dimensional continuous fluid plasma model. The calculation results show the dominant positive charged particle became O{sup +} from O{sub 2}{sup +} with increasing amount of O radical in O{sub 2}. The plasma positive densities are not greatly affected if O radical content did not exceed 1 % of O{sub 2}. It was concluded that O{sub 2} plasma structure can be evaluated by source gas plasma calculation neglecting radical formation, since O radical formation in the O{sub 2} plasma is estimated as less than 0.2 % of O{sub 2}. (author)

A Unified Gas Kinetic Scheme for Transport and Collision Effects in Plasma

Directory of Open Access Journals (Sweden)

Dongxin Pan

2018-05-01

Full Text Available In this study, the Boltzmann equation with electric acceleration term is discretized and solved by the unified gas-kinetic scheme (UGKS. The charged particle transport driven by electric field is included in the electric acceleration term. To capture non-equilibrium distribution function, the probability distribution functions of gas is discretized in a discrete velocity space. After discretization, the numerical flux for distribution function is computed to update the microscopic and macroscopic states. The flux is decided by an integral solution of Boltzmann equation based on characteristic problem. An electron-ion collision model is introduced in the Boltzmann Bhatnagar-Gross-Krook (BGK equation. This finite volume method for the UGKS couples the free transport and long-range interaction between particles. For simplicity, the electric field induced by charged particles is controlled by the Poisson’s equation, which is solved using the Green’s function for two dimensional plasma system subjected to the symmetry or periodic boundary conditions. Two numerical cases, linear Landau damping and Gaussian beam, are carried out to validate the proposed method. The linear electron plasma wave damping is simulated based on electron-ion collision operator. Comparison results show good accuracy and higher efficiency than particle based methods. Difference between Poisson’s equation and complete electromagnetic Maxwell equation is presented by numerical results based on the two models. Highly non-equilibrium and rarefied plasma flows, such as electron flows driven by electromagnetic field, can be simulated easily. The UGKS-Poisson model is proved to be promising in plasma flow simulation.

Fuel gas and char from pyrolysis of waste paper in a microwave plasma reactor

Energy Technology Data Exchange (ETDEWEB)

Khongkrapan, Parin; Thanompongchart, Patipat; Tippayawong, Nakorn; Kiatsiriroat, Tanongkiat [Department of Mechanical Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai 50200 (Thailand)

2013-07-01

In this study, a microwave plasma reactor was used for pyrolysis of waste papers. The effects of different argon flow rates on char and gas generation were investigated. Changes in carbon and oxygen contents from those in paper to char were significant. Char yield of over 25 % was obtained with the heating value of about 38 MJ/kg. Average gas yield and total content of combustible fraction (CO, CH4 and H2) in the gas product were 2.56 m3/kg and 36 %, respectively. The heating value of gas product and carbon conversion efficiency of the process were maximum at 6.0 MJ/m3 and 73 %, respectively.

Abatement of global warming gas emissions from semiconductor manufacturing processes by non-thermal plasma-catalyst systems

Energy Technology Data Exchange (ETDEWEB)

Chang, J-S.; Urashima, K. [McMaster Univ., McIARS and Dept. Eng. Phys., Hamilton, Ontario (Canada)

2009-07-01

Emission of various hazardous air pollutants (HAPs) and greenhouse gases including perfluoro-compounds (PFCs) from semiconductor industries may cause significant impact on human health and the global environment, has attracted much public attention. In this paper, an application of nonthermal plasma-adsorbent system for a removal of PFCs emission from semiconductor process flue gases is experimentally investigated. The non-thermal plasma reactor used is the ferro-electric packed-bed type barrier discharge plasma and adsorbent reactor used is Zeolite bed reactor. The results show that for a simulated semiconductor process flue gas with C{sub 2}F{sub 6} (2000ppm)/ CF{sub 4}(1000ppm)/ N{sub 2}O(1000ppm)/ N{sub 2}/ Air mixture, 54% of C{sub 2}F{sub 6} and 32% of CF{sub 4} were decomposed by the plasma reactor and 100% of C{sub 2}F{sub 6} and 98% of CF{sub 4} were removed by plasma reactor/Zeolite adsorbent hybrid system. For a simulated semiconductor process flue gas with NF{sub 3} (2000ppm)/ SiF{sub 4}(1000ppm)/ N{sub 2}O(200ppm)/ N{sub 2}/ Air mixture, 92% of NF{sub 3} and 32% of SiF{sub 4} were decomposed by the plasma reactor and total (100%) removal of the pollutant gases was achieved by plasma reactor/Zeolite adsorbent hybrid system. (author)

Pyrolysis/gasification of biomass for synthetic fuel production using a hybrid gas- water stabilized plasma torch

Czech Academy of Sciences Publication Activity Database

Van Oost, G.; Hrabovský, Milan; Kopecký, Vladimír; Konrád, Miloš; Hlína, Michal; Kavka, Tetyana

2008-01-01

Roč. 83, č. 1 (2008), s. 209-212 ISSN 0042-207X R&D Projects: GA ČR GA202/08/1084 Institutional research plan: CEZ:AV0Z20430508 Keywords : Thermal plasma * pyrolysis * biomass gasification Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.114, year: 2008

Hydrogen peroxide as a sustainable energy carrier: Electrocatalytic production of hydrogen peroxide and the fuel cell

International Nuclear Information System (INIS)

Fukuzumi, Shunichi; Yamada, Yusuke; Karlin, Kenneth D.

2012-01-01

This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O 2 -reduction to produce water occurs depends on the types of metals and ligands that are utilized. Those factors controlling the two processes are discussed in terms of metal–oxygen intermediates involved in the catalysis. Metal complexes acting as catalysts for selective two-electron reduction of oxygen can be utilized as metal complex-modified electrodes in the electrocatalytic reduction to produce hydrogen peroxide. Hydrogen peroxide thus produced can be used as a fuel in a hydrogen peroxide fuel cell. A hydrogen peroxide fuel cell can be operated with a one-compartment structure without a membrane, which is certainly more promising for the development of low-cost fuel cells as compared with two compartment hydrogen fuel cells that require membranes. Hydrogen peroxide is regarded as an environmentally benign energy carrier because it can be produced by the electrocatalytic two-electron reduction of O 2 , which is abundant in air, using solar cells; the hydrogen peroxide thus produced could then be readily stored and then used as needed to generate electricity through the use of hydrogen peroxide fuel cells.

Hydrogen Peroxide as a Sustainable Energy Carrier: Electrocatalytic Production of Hydrogen Peroxide and the Fuel Cell.

Science.gov (United States)

Fukuzumi, Shunichi; Yamada, Yusuke; Karlin, Kenneth D

2012-11-01

This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O 2 -reduction to produce water occurs depends on the types of metals and ligands that are utilized. Those factors controlling the two processes are discussed in terms of metal-oxygen intermediates involved in the catalysis. Metal complexes acting as catalysts for selective two-electron reduction of oxygen can be utilized as metal complex-modified electrodes in the electrocatalytic reduction to produce hydrogen peroxide. Hydrogen peroxide thus produced can be used as a fuel in a hydrogen peroxide fuel cell. A hydrogen peroxide fuel cell can be operated with a one-compartment structure without a membrane, which is certainly more promising for the development of low-cost fuel cells as compared with two compartment hydrogen fuel cells that require membranes. Hydrogen peroxide is regarded as an environmentally benign energy carrier because it can be produced by the electrocatalytic two-electron reduction of O 2 , which is abundant in air, using solar cells; the hydrogen peroxide thus produced could then be readily stored and then used as needed to generate electricity through the use of hydrogen peroxide fuel cells.

Effect of tetrahydrocurcumin on lipid peroxidation and lipids in streptozotocin-nicotinamide-induced diabetic rats.

Science.gov (United States)

Murugan, Pidaran; Pari, Leelavinothan

2006-08-01

Hyperlipidaemia is an associated complication of diabetes mellitus. We recently reported that tetrahydrocurcumin lowered the blood glucose in diabetic rats. In the present study, we have investigated the effect of tetrahydrocurcumin, one of the active metabolites of curcumin on lipid profile and lipid peroxidation in streptozotocin-nicotinamide-induced diabetic rats. Tetrahydrocurcumin 80 mg/kg body weight was administered orally to diabetic rats for 45 days, resulted a significant reduction in blood glucose and significant increase in plasma insulin in diabetic rats, which proved its antidiabetic effect. Tetrahydrocurcumin also caused a significant reduction in lipid peroxidation (thiobarbituric acid reactive substances and hydroperoxides) and lipids (cholesterol, triglycerides, free fatty acids and phospholipids) in serum and tissues, suggesting its role in protection against lipid peroxidation and its antihyperlipidemic effect. Tetrahydrocurcumin showed a better effect when compared with curcumin. Results of the present study indicate that tetrahydrocurcumin showed antihyperlipidaemic effect in addition to its antidiabetic effect in type 2 diabetic rats.

Spectroscopic determination of the magnetic field distribution in a gas-puff Z-pinch plasma

Energy Technology Data Exchange (ETDEWEB)

Gregorian, L; Davara, G; Kroupp, E; Maron, Y [Weizmann Institute of Science, Rehovot (Israel). Dept. of Particle Physics

1997-12-31

The time dependent radial distribution of the magnetic field in a gas-puff Z-pinch plasma has been determined by observing the Zeeman effect on emission lines, allowed for by polarization spectroscopy and high accuracy line-profile measurements. A modeling scheme, based on a 1-D magnetic diffusion equation, is used to fit the experimental data. The plasma conductivity inferred from the field distribution was found to be consistent with the Spitzer conductivity. The current density distribution and the time dependent plasma region in which the entire circuit current flows were determined. (author). 3 figs., 6 refs.

Sterilization of Fusarium oxysporum by treatment of non-thermalequilibrium plasma in nutrient solution

Science.gov (United States)

Yasui, Shinji; Seki, Satoshi; Yoshida, Ryohei; Shoji, Kazuhiro; Terazoe, Hitoshi

2016-01-01

Fusarium wilt of spinach due to F. oxysporum infection is one of the most destructive root diseases in hydroponics in factories using the nutrient film technique. We investigated new technologies for the sterilization of microconidia of F. oxysporum by using a non-thermalequilibrium plasma treatment method in nutrient solution. Specifically, we investigated the sterilization capabilities of five types of gas (air, O2, N2, He, and Ar) used for plasma generation. The highest sterilization capability was achieved by using O2 plasma. However, ozone, which causes growth inhibition, was then generated and released into the atmosphere. The sterilization capability was lower when N2 or air plasma was used in the nutrient solution. It was confirmed that sterilization can be achieved by plasma treatment using inert gases that do not generate ozone; therefore, we determined that Ar plasma is the most preferable. In addition, we investigated the sterilization capabilities of other factors associated with Ar plasma generation, without direct plasma treatment. However, none of these other factors, which included Ar bubbling, pH reduction, increased temperature, hydrogen peroxide concentration, and UV radiation, could completely reproduce the results of direct plasma treatment. We assume that radicals such as O or OH may contribute significantly to the sterilization of microconidia of F. oxysporum in a nutrient solution.

Quantification of plasma myo-inositol using gas chromatography-mass spectrometry.

Science.gov (United States)

Guo, Jin; Shi, Yingfei; Xu, Chengbao; Zhong, Rugang; Zhang, Feng; Zhang, Ting; Niu, Bo; Wang, Jianhua

2016-09-01

Myo-inositol (MI) deficiency is associated with an increased risk for neural tube defects (NTDs), mental disorders and metabolic diseases. We developed a gas chromatography-mass spectrometry (GC-MS) method to detect MI in human plasma, which was accurate, relatively efficient and convenient for clinical application. An external standard method was used for determination of plasma MI. Samples were analyzed by GC-MS after derivatization. The stable-isotope labeled internal standard approach was used to validate the method's accuracy. Alpha fetal protein (AFP) was detected by chemiluminescence immunoassay. The method was validated by determining the linearity, sensitivity and recovery rate. There was a good agreement between the internal standard approach and the present method. The NTD-affected pregnancies showed lower plasma MI (P=0.024) and higher AFP levels (P=0.001) than control. Maternal MI level showed a better discrimination in spina bifida subgroup, while AFP level showed a better discrimination in anencephaly subgroup after stratification analysis. We developed a sensitive and reliable method for the detection of clinical plasma MI, which might be a marker for NTDs screening, and established fundamental knowledge for clinical diagnosis and prevention for the diseases related to disturbed MI metabolism. Copyright © 2016 Elsevier B.V. All rights reserved.

Noble Gas Plasmas with Metallic Conductivity: A New Light Source from a New State of Matter

Science.gov (United States)

2015-11-01

triggered by uv lamp Spark Blocking Laser Pulse that is Incident from the Right Laser PulseSpark Discharge High-Power Dense Microplasma Optical Switch...flash width ~35.ps Plasma density ~1022/cc Radius ~ 1.μm • fs laser breakdown In a dense gas Tachibana Spark discharge Electrode spacing=100μm...Demonstration of Opaque Plasma Discharge Blocking Intense Laser Pulse-due to formation of dense plasma condensate b) Intense laser pulse arrested at

Controlled gas-liquid interfacial plasmas for synthesis of nano-bio-carbon conjugate materials

Science.gov (United States)

Kaneko, Toshiro; Hatakeyama, Rikizo

2018-01-01

Plasmas generated in contact with a liquid have been recognized to be a novel reactive field in nano-bio-carbon conjugate creation because several new chemical reactions have been yielded at the gas-liquid interface, which were induced by the physical dynamics of non-equilibrium plasmas. One is the ion irradiation to a liquid, which caused the spatially selective dissociation of the liquid and the generation of additive reducing and oxidizing agents, resulting in the spatially controlled synthesis of nanostructures. The other is the electron irradiation to a liquid, which directly enhanced the reduction action at the plasma-liquid interface, resulting in temporally controlled nanomaterial synthesis. Using this novel reaction field, gold nanoparticles with controlled interparticle distance were synthesized using carbon nanotubes as a template. Furthermore, nanoparticle-biomolecule conjugates and nanocarbon-biomolecule conjugates were successfully synthesized by an aqueous-solution contact plasma and an electrolyte plasma, respectively, which were rapid and low-damage processes suitable for nano-bio-carbon conjugate materials.

Destruction kinetic of PCDDs/Fs in MSWI fly ash using microwave peroxide oxidation.

Science.gov (United States)

Chang, Yu-Min; Fang, Wen-Bin; Tsai, Kuo-Sheng; Kao, Jimmy C M; Lin, Kae-Long; Chen, Ching-Ho

2015-01-01

Microwave peroxide oxidation is a less greenhouse gas emission and energy-efficient technology to destroy toxic organic compounds in hazardous waste. The research novelty is to adopt the innovative microwave peroxide oxidation in H2SO4/HNO3 solution to efficiently destroy the polychlorinated dibenzo-p-dioxins (PCDDs)/Fs in municipal solid waste incineration fly ash. The major objective of this paper is to study dynamic destruction of PCDDs/Fs using the microwave peroxide oxidation. Almost all PCDDs/Fs in the raw fly ash can be destructed in 120 min at a temperature of 423 K using the microwave peroxide oxidation treatment. It was found that the microwave peroxide oxidation provides the potential to destruct the PCDDs/Fs content in municipal solid waste incinerator (MSWI) fly ash to a low level as a function of treatment time. A useful kinetic correlation between destruction efficiency and treatment conditions is proposed on the basis of the experimental data obtained in this study. The significance of this work in terms of practical engineering applications is that the necessary minimum treatment time can be solved using a proposed graphic illustration method, by which the minimum treatment time is obtained if the desired destruction efficiency and treatment temperature are known. Because of inorganic salt dissolution, the temperature would be a critical factor facilitating the parts of fly ash dissolution. Material loss problem caused by the microwave peroxide oxidation and the effects of treatment time and temperature are also discussed in this paper.

Morphology of Gas Release in Physical Simulants

Energy Technology Data Exchange (ETDEWEB)

Daniel, Richard C.; Burns, Carolyn A.; Crawford, Amanda D.; Hylden, Laura R.; Bryan, Samuel A.; MacFarlan, Paul J.; Gauglitz, Phillip A.

2014-07-03

This report documents testing activities conducted as part of the Deep Sludge Gas Release Event Project (DSGREP). The testing described in this report focused on evaluating the potential retention and release mechanisms of hydrogen bubbles in underground radioactive waste storage tanks at Hanford. The goal of the testing was to evaluate the rate, extent, and morphology of gas release events in simulant materials. Previous, undocumented scoping tests have evidenced dramatically different gas release behavior from simulants with similar physical properties. Specifically, previous gas release tests have evaluated the extent of release of 30 Pa kaolin and 30 Pa bentonite clay slurries. While both materials are clays and both have equivalent material shear strength using a shear vane, it was found that upon stirring, gas was released immediately and completely from bentonite clay slurry while little if any gas was released from the kaolin slurry. The motivation for the current work is to replicate these tests in a controlled quality test environment and to evaluate the release behavior for another simulant used in DSGREP testing. Three simulant materials were evaluated: 1) a 30 Pa kaolin clay slurry, 2) a 30 Pa bentonite clay slurry, and 3) Rayleigh-Taylor (RT) Simulant (a simulant designed to support DSGREP RT instability testing. Entrained gas was generated in these simulant materials using two methods: 1) application of vacuum over about a 1-minute period to nucleate dissolved gas within the simulant and 2) addition of hydrogen peroxide to generate gas by peroxide decomposition in the simulants over about a 16-hour period. Bubble release was effected by vibrating the test material using an external vibrating table. When testing with hydrogen peroxide, gas release was also accomplished by stirring of the simulant.

plasma modes behaviors and electron injection influence in an audio-ultrasonic air gas discharge

International Nuclear Information System (INIS)

Ragheb, M.S.; Haleem, N.A.

2010-01-01

the main purpose of this study is to investigate the favorable conditions for the production of plasma particle acceleration in an audio-ultrasonic air gas discharge of 20 cm long and 34 mm diameter.it is found that according to the applied conditions the formed plasma changes its behavior and overtakes diverse modes of different characteristics. the pressure, the voltage, and the frequency applied to the plasma determine its proper state. both experimental data collection and optical observations are introduced to clarify and to put in evidence the present plasma facts. the distribution of the electrons density along the plasma tube draws in average the electric field distribution of the ionization waves. in addition, the plasma is studied with and without electrons injection in order to investigate its influence . it is found that the electron injection decreases the plasma intensity and the plasma temperature, while it increases the discharge current. in turn, the decrease of the plasma temperature decreases the plasma oscillations and enhances the plasma instability. on the other hand,the enhancement of the plasma instability performs good conditions for electron acceleration. as a result, the qualified mode for particles acceleration is attained and its conditions are retrieved and defined for that purpose.

On the use of pulsed Dielectric Barrier Discharges to control the gas-phase composition of atmospheric pressure air plasmas

Science.gov (United States)

Barni, R.; Biganzoli, I.; Dell'Orto, E.; Riccardi, C.

2014-11-01

We presents results obtained from the numerical simulation of the gas-phase chemical kinetics in atmospheric pressure air non-equilibrium plasmas. In particular we have addressed the effect of pulsed operation mode of a plane dielectric barrier discharge. It was conjectured that the large difference in the time scales involved in the fast dissociation of oxygen molecules in plasma and their subsequent reactions to produce ozone and nitrogen oxides, makes the presence of a continuously repeated plasma production unnecessary and a waste of electrical power and thus efficiency. In order to test such suggestion we have performed a numerical study of the composition and the temporal evolution of the gas-phase of atmospheric pressure air non-equilibrium plasmas. Comparison with experimental findings in a dielectric barrier discharge with an electrode configuration symmetrical and almost ideally plane is briefly addressed too, using plasma diagnostics to extract the properties of the single micro-discharges and a sensor to measure the concentration of ozone produced by the plasma.

On the use of pulsed Dielectric Barrier Discharges to control the gas-phase composition of atmospheric pressure air plasmas

International Nuclear Information System (INIS)

Barni, R; Biganzoli, I; Dell'Orto, E; Riccardi, C

2014-01-01

We presents results obtained from the numerical simulation of the gas-phase chemical kinetics in atmospheric pressure air non-equilibrium plasmas. In particular we have addressed the effect of pulsed operation mode of a plane dielectric barrier discharge. It was conjectured that the large difference in the time scales involved in the fast dissociation of oxygen molecules in plasma and their subsequent reactions to produce ozone and nitrogen oxides, makes the presence of a continuously repeated plasma production unnecessary and a waste of electrical power and thus efficiency. In order to test such suggestion we have performed a numerical study of the composition and the temporal evolution of the gas-phase of atmospheric pressure air non-equilibrium plasmas. Comparison with experimental findings in a dielectric barrier discharge with an electrode configuration symmetrical and almost ideally plane is briefly addressed too, using plasma diagnostics to extract the properties of the single micro-discharges and a sensor to measure the concentration of ozone produced by the plasma

Ascorbic acid protects lipids in human plasma and low-density lipoprotein against oxidative damage

Energy Technology Data Exchange (ETDEWEB)

Frei, B. (Department of Nutrition, Harvard School of Public Health, Boston, MA (Unites States))

1991-12-01

The authors exposed human blood plasma and low-density lipoprotein (LDL) to many different oxidative challenges and followed the temporal consumption of endogenous antioxidants in relation to the initiation of oxidative damage. Under all types of oxidizing conditions, ascorbic acid completely protects lipids in plasma and LDL against detectable peroxidative damage as assessed by a specific and highly sensitive assay for lipid peroxidation. Ascorbic acid proved to be superior to the other water-soluble plasma antioxidants bilirubin, uric acid, and protein thiols as well as to the lipoprotein-associated antioxidants alpha-tocopherol, ubiquinol-10, lycopene, and beta-carotene. Although these antioxidants can lower the rate of detectable lipid peroxidation, they are not able to prevent its initiation. Only ascorbic acid is reactive enough to effectively intercept oxidants in the aqueous phase before they can attack and cause detectable oxidative damage to lipids.

Laser-induced carbon plasma emission spectroscopic measurements on solid targets and in gas-phase optical breakdown

International Nuclear Information System (INIS)

Nemes, Laszlo; Keszler, Anna M.; Hornkohl, James O.; Parigger, Christian

2005-01-01

We report measurements of time- and spatially averaged spontaneous-emission spectra following laser-induced breakdown on a solid graphite/ambient gas interface and on solid graphite in vacuum, and also emission spectra from gas-phase optical breakdown in allene C3H4 and helium, and in CO2 and helium mixtures. These emission spectra were dominated by CII (singly ionized carbon), CIII (doubly ionized carbon), hydrogen Balmer beta (H b eta), and Swan C2 band features. Using the local thermodynamic equilibrium and thin plasma assumptions, we derived electron number density and electron temperature estimates. The former was in the 1016 cm -3 range, while the latter was found to be near 20000 K. In addition, the vibration-rotation temperature of the Swan bands of the C2 radical was determined to be between 4500 and 7000 K, using an exact theoretical model for simulating diatomic emission spectra. This temperature range is probably caused by the spatial inhomogeneity of the laser-induced plasma plume. Differences are pointed out in the role of ambient CO2 in a solid graphite target and in gas-phase breakdown plasma

Experimental study of the effect of gas nature on plasma arc cutting of mild steel

Czech Academy of Sciences Publication Activity Database

Kavka, Tetyana; Mašláni, Alan; Hrabovský, Milan; Křenek, Petr; Stehrer, T.; Pauser, H.

2013-01-01

Roč. 46, č. 22 (2013), s. 224011-224011 ISSN 0022-3727 R&D Projects: GA ČR GAP205/11/2070 Institutional support: RVO:61389021 Keywords : Arc cutting * steam plasma cutting * energy balance Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.521, year: 2013 http://iopscience.iop.org/0022-3727/46/22/224011/pdf/0022-3727_46_22_224011.pdf

3D printing of gas jet nozzles for laser-plasma accelerators

Energy Technology Data Exchange (ETDEWEB)

Döpp, A.; Guillaume, E.; Thaury, C.; Gautier, J.; Ta Phuoc, K.; Malka, V. [LOA, ENSTA ParisTech, CNRS, École Polytechnique, Université Paris-Saclay, 828 Boulevard des Maréchaux, 91762 Palaiseau Cedex (France)

2016-07-15

Recent results on laser wakefield acceleration in tailored plasma channels have underlined the importance of controlling the density profile of the gas target. In particular, it was reported that the appropriate density tailoring can result in improved injection, acceleration, and collimation of laser-accelerated electron beams. To achieve such profiles, innovative target designs are required. For this purpose, we have reviewed the usage of additive layer manufacturing, commonly known as 3D printing, in order to produce gas jet nozzles. Notably we have compared the performance of two industry standard techniques, namely, selective laser sintering (SLS) and stereolithography (SLA). Furthermore we have used the common fused deposition modeling to reproduce basic gas jet designs and used SLA and SLS for more sophisticated nozzle designs. The nozzles are characterized interferometrically and used for electron acceleration experiments with the SALLE JAUNE terawatt laser at Laboratoire d’Optique Appliquée.

Protective effect of morin on lipid peroxidation and lipid profile in ammonium chloride-induced hyperammonemic rats

Directory of Open Access Journals (Sweden)

S Subash

2012-04-01

Full Text Available Objective: To evaluated the protective effects of morin (3, 5, 7, 2', 4'-pentahydroxyflavone on lipid peroxidation and lipid levels during ammonium chloride (AC induced hyperammonemia in experimental rats. Methods: Thirty two male albino Wistar rats, which are weighing between 180-200 g were used for the study. The hyperammonemia was induced by administration of 100 mg/kg body weight (i.p. thrice in a week of AC for 8 weeks. Rats were treated with morin at dose (30 mg/kg body weight via intragastric intubations together with AC. At the end of experimental duration, blood ammonia, plasma urea, lipid peroxidation indices [thiobarbituric acid reactive substances, hydroperoxides and lipid levels (cholesterol, triglycerides, free fatty acids and phospholipids] in serum and tissues were analysed to evaluate the antiperoxidative and antilipidemic effects of morin. Results: Ammonia, urea, lipid peroxidative indices and lipid levels were significantly increased in AC administered group. Morin treatment resulted in positive modulation of ammonia, urea, lipid peroxidative indices and lipid levels. Morin administration to normal rats did not exhibit any significant changes in any of the parameters studied. Conclusions: It can be concluded that the beneficial effect of morin on ammonia, urea, lipid peroxidative indices and lipid levels could be due to its antioxidant property.

Detection of hydrogen peroxide with graphyne

Science.gov (United States)

Majidi, R.; Karami, A. R.

2013-12-01

The effect of hydrogen peroxide on the electronic properties of graphyne has been investigated to explore the possibility of using graphyne based biosensor. We have used density functional theory to study the electronic properties of γ-graphyne in the presence of different number of hydrogen peroxide. The optimal adsorption position, orientation, and distance of hydrogen peroxide adsorbed on the graphyne sheet have been determined by calculating adsorption energy. It is found that γ-graphyne which is an intrinsic semiconductor becomes an n-type semiconductor due to the presence of hydrogen peroxide. The energy band gap of γ-graphyne is decreased by increasing the number of hydrogen peroxide. The results demonstrate that γ-graphyne is a promising candidate for biosensor application because of its electrical sensitivity to hydrogen peroxide.

Sensory and Functionality Differences of Whey Protein Isolate Bleached by Hydrogen or Benzoyl Peroxide.

Science.gov (United States)

Smith, Tucker J; Foegeding, E Allen; Drake, MaryAnne

2015-10-01

Whey protein is a highly functional food ingredient used in a wide variety of applications. A large portion of fluid whey produced in the United States is derived from Cheddar cheese manufacture and contains annatto (norbixin), and therefore must be bleached. The objective of this study was to compare sensory and functionality differences between whey protein isolate (WPI) bleached by benzoyl peroxide (BP) or hydrogen peroxide (HP). HP and BP bleached WPI and unbleached controls were manufactured in triplicate. Descriptive sensory analysis and gas chromatography-mass spectrometry were conducted to determine flavor differences between treatments. Functionality differences were evaluated by measurement of foam stability, protein solubility, SDS-PAGE, and effect of NaCl concentration on gelation relative to an unbleached control. HP bleached WPI had higher concentrations of lipid oxidation and sulfur containing volatile compounds than both BP and unbleached WPI (P protein loss at pH 4.6 of WPI decreased by bleaching with either hydrogen peroxide or benzoyl peroxide (P whey with either BP or HP resulted in protein degradation, which likely contributed to functionality differences. These results demonstrate that bleaching has flavor effects as well as effects on many of the functionality characteristics of whey proteins. Whey protein isolate (WPI) is often used for its functional properties, but the effect of oxidative bleaching chemicals on the functional properties of WPI is not known. This study identifies the effects of hydrogen peroxide and benzoyl peroxide on functional and flavor characteristics of WPI bleached by hydrogen and benzoyl peroxide and provides insights for the product applications which may benefit from bleaching. © 2015 Institute of Food Technologists®

Steam Plasma Flows Generated in Gerdien Arc: Environment for Energy Gas Production from Organics and for Surface Coatings

Czech Academy of Sciences Publication Activity Database

Hrabovský, Milan

2011-01-01

Roč. 6, č. 5 (2011), s. 792-801 ISSN 1880-5558. [Seventh International Conference on Flow Dynamics. Sendai, 01.11.2010-03.11.2010] R&D Projects: GA ČR GAP205/11/2070 Institutional research plan: CEZ:AV0Z20430508 Keywords : Thermal Plasma * Dc Arc Plasma Torch * Gerdien Arc * Plasma Gasification Subject RIV: BL - Plasma and Gas Discharge Physics http://www.jstage.jst.go.jp/article/jfst/6/5/792/_pdf

Effects of pulse frequency of input power on the physical and chemical properties of pulsed streamer discharge plasmas in water

Czech Academy of Sciences Publication Activity Database

Ruma, Ruma.; Lukeš, Petr; Aoki, N.; Doležalová, Eva; Hosseini, S.H.R.; Sakugawa, T.; Akiyama, H.

2013-01-01

Roč. 46, č. 12 (2013), s. 125202-125202 ISSN 0022-3727 R&D Projects: GA ČR(CZ) GD104/09/H080 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100431203 Program:M Institutional support: RVO:61389021 Keywords : discharge in water * pulsed power * pulse frequency * hydrogen peroxide * organic dye * bacteria * generator * liquids Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.521, year: 2013 http://dx.doi.org/10.1088/0022-3727/46/12/125202

Gas Diffusion Barriers Prepared by Spatial Atmospheric Pressure Plasma Enhanced ALD.

Science.gov (United States)

Hoffmann, Lukas; Theirich, Detlef; Pack, Sven; Kocak, Firat; Schlamm, Daniel; Hasselmann, Tim; Fahl, Henry; Räupke, André; Gargouri, Hassan; Riedl, Thomas

2017-02-01

In this work, we report on aluminum oxide (Al 2 O 3 ) gas permeation barriers prepared by spatial ALD (SALD) at atmospheric pressure. We compare the growth characteristics and layer properties using trimethylaluminum (TMA) in combination with an Ar/O 2 remote atmospheric pressure plasma for different substrate velocities and different temperatures. The resulting Al 2 O 3 films show ultralow water vapor transmission rates (WVTR) on the order of 10 -6 gm -2 d -1 . In notable contrast, plasma based layers already show good barrier properties at low deposition temperatures (75 °C), while water based processes require a growth temperature above 100 °C to achieve equally low WVTRs. The activation energy for the water permeation mechanism was determined to be 62 kJ/mol.

The analog of Blanc's law for drift velocities of electrons in gas mixtures in weakly ionized plasma

International Nuclear Information System (INIS)

Chiflikian, R.V.

1995-01-01

The analog of Blanc's law for drift velocities of electrons in multicomponent gas mixtures in weakly ionized spatially homogeneous low-temperature plasma is derived. The obtained approximate-analytical expressions are valid for average electron energy in the 1--5 eV range typical for plasma conditions of low-pressure direct current (DC) discharges. The accuracy of these formulas is ±5%. The analytical criterion of the negative differential conductivity (NDC) of electrons in binary mixtures of gases is obtained. NDC of electrons is predicted in He:Kr and He:Xe rare gas mixtures. copyright 1995 American Institute of Physics

Plasma/neutral gas transport in divertors and limiters

International Nuclear Information System (INIS)

Gierszewski, P.J.

1983-09-01

The engineering design of the divertor and first wall region of fusion reactors requires accurate knowledge of the energies and particle fluxes striking these surfaces. Simple calculations indicate that approx. 10 MW/m 2 heat fluxes and approx. 1 cm/yr erosion rates are possible, but there remain fundamental physics questions that bear directly on the engineering design. The purpose of this study was to treat hydrogen plasma and neutral gas transport in divertors and pumped limiters in sufficient detail to answer some of the questions as to the actual conditions that will be expected in fusion reactors. This was accomplished in four parts: (1) a review of relevant atomic processes to establish the dominant interactions and their data base; (2) a steady-state coupled O-D model of the plasma core, scrape-off layer and divertor exhaust to determine gross modes of operation and edge conditions; (3) a 1-D kinetic transport model to investigate the case of collisionless divertor exhaust, including non-Maxwellian ions and neutral atoms, highly collisional electrons, and a self-consistent electric field; and (4) a 3-D Monte Carlo treatment of neutral transport to correctly account for geometric effects

NOx removal from the flue gas of oil-fired boiler using a multistage plasma-catalyst hybrid system

International Nuclear Information System (INIS)

Park, Sung Youl; Deshwal, Bal Raj; Moon, Seung Hyun

2008-01-01

The study on removal of NO x from the flue gas of oil-fired boiler has been carried out using non-thermal plasma cum catalyst hybrid reactor at 150 C. Propylene (C 3 H 6 ) was used as a reducing agent. A multistage plasma-catalyst hybrid reactor was newly designed and successfully operated to clean up the flue gas stream having a flow rate of 30 Nm 3 /h. TiO 2 and Pd/ZrO 2 wash-coated on cordierite honeycomb were used as catalysts in the present study. Though the plasma-catalyst hybrid reactor with TiO 2 showed good activity on the removal of NO yet it removed only 50-60% of NO x because a significant portion of NO oxidized to NO 2 . On the contrary, the plasma-catalyst hybrid reactor with Pd/ZrO 2 removed about 50% of inlet NO with a negligible amount of NO oxidation into NO 2 . The plasma/dual-catalysts hybrid system (front two units of plasma-Pd/ZrO 2 + rear two units of plasma/TiO 2 ) proved to be very promising in NO x removal in the presence of C 3 H 6 . DeNO x efficiency of about 74% has been achieved at a space velocity of 3300/h at 150 C. (author)

Pyrite-enhanced methylene blue degradation in non-thermal plasma water treatment reactor

Energy Technology Data Exchange (ETDEWEB)

Benetoli, Luis Otavio de Brito, E-mail: luskywalcker@yahoo.com.br [Departamento de Quimica, Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Cadorin, Bruno Mena; Baldissarelli, Vanessa Zanon [Departamento de Quimica, Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Geremias, Reginaldo [Departamento de Ciencias Rurais, Universidade Federal de Santa Catarina (UFSC), Curitibanos, SC (Brazil); Goncalvez de Souza, Ivan [Departamento de Quimica, Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Debacher, Nito Angelo, E-mail: debacher@qmc.ufsc.br [Departamento de Quimica, Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

2012-10-30

Highlights: Black-Right-Pointing-Pointer We use O{sub 2} as the feed gas and pyrite was added to the non-thermal plasma reactor. Black-Right-Pointing-Pointer The methylene blue removal by NTP increased in the presence of pyrite. Black-Right-Pointing-Pointer The total organic carbon content decreased substantially. Black-Right-Pointing-Pointer The acute toxicity test showed that the treated solution is not toxic. Black-Right-Pointing-Pointer The dye degradation occurs via electron impact as well as successive hydroxylation. - Abstract: In this study, methylene blue (MB) removal from an aqueous phase by electrical discharge non-thermal plasma (NTP) over water was investigated using three different feed gases: N{sub 2}, Ar, and O{sub 2}. The results showed that the dye removal rate was not strongly dependent on the feed gas when the electrical current was kept the same for all gases. The hydrogen peroxide generation in the water varied according to the feed gas (N{sub 2} < Ar < O{sub 2}). Using O{sub 2} as the feed gas, pyrite was added to the reactor in acid medium resulting in an accentuated increase in the dye removal, which suggests that pyrite acts as a Fenton-like catalyst. The total organic carbon (TOC) content of the dye solution decreased slightly as the plasma treatment time increased, but in the presence of the pyrite catalyst the TOC removal increased substantially. The acute toxicity test using Artemia sp. microcrustaceans showed that the treated solution is not toxic when Ar, O{sub 2} or O{sub 2}-pyrite is employed. Electrospray ionization mass spectrometry analysis (ESI-MS) of the treated samples indicated that the dye degradation occurs via high energy electron impact as well as successive hydroxylation in the benzene rings of the dye molecules.

Roles of individual radicals generated by a submerged dielectric barrier discharge plasma reactor during Escherichia coli O157:H7 inactivation

Energy Technology Data Exchange (ETDEWEB)

Khan, Muhammad Saiful Islam [Department of Food Biotechnology, University of Science and Technology, Daejeon, 305-350 (Korea, Republic of); Lee, Eun-Jung [Food Safety Research Group, Korea Food Research Institute, Seongnam-si, Gyeonggi-Do (Korea, Republic of); Kim, Yun-Ji, E-mail: yunji@kfri.re.kr [Department of Food Biotechnology, University of Science and Technology, Daejeon, 305-350 (Korea, Republic of); Food Safety Research Group, Korea Food Research Institute, Seongnam-si, Gyeonggi-Do (Korea, Republic of)

2015-10-15

A submerged dielectric barrier discharge plasma reactor (underwater DBD) has been used on Escherichia coli O157:H7 (ATCC 35150). Plasma treatment was carried out using clean dry air gas to investigate the individual effects of the radicals produced by underwater DBD on an E. coli O157:H7 suspension (8.0 log CFU/ml). E. coli O157:H7 was reduced by 6.0 log CFU/ml for 2 min of underwater DBD plasma treatment. Optical Emission Spectra (OES) shows that OH and NO (α, β) radicals, generated by underwater DBD along with ozone gas. E. coli O157:H7 were reduced by 2.3 log CFU/ml for 10 min of underwater DBD plasma treatment with the terephthalic acid (TA) OH radical scavenger solution, which is significantly lower (3.7 log CFU/ml) than the result obtained without using the OH radical scavenger. A maximum of 1.5 ppm of ozone gas was produced during the discharge of underwater DBD, and the obtained reduction difference in E.coli O157:H7 in presence and in absence of ozone gas was 1.68 log CFU/ml. The remainder of the 0.62 log CFU/ml reduction might be due to the effect of the NO (α, β) radicals or due to the combined effect of all the radicals produced by underwater DBD. A small amount of hydrogen peroxide was also generated but does not play any role in E. coli O157:H7 inactivation.

Degradation of methylene blue by radio frequency plasmas in water under ultraviolet irradiation

Energy Technology Data Exchange (ETDEWEB)

Maehara, Tsunehiro, E-mail: maehara@phys.sci.ehime-u.ac.jp [Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577 (Japan); Nishiyama, Kyohei; Onishi, Shingo; Mukasa, Shinobu; Toyota, Hiromichi [Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577 (Japan); Kuramoto, Makoto [Integrated Center for Science, Ehime University, Matsuyama 790-8577 (Japan); Nomura, Shinfuku [Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577 (Japan); Kawashima, Ayato [Faculty of Agriculture, Ehime University, Matsuyama 790-8566 (Japan)

2010-02-15

The degradation of methylene blue by radio frequency (RF) plasmas in water under ultraviolet (UV) irradiation was studied experimentally. When the methylene blue solution was exposed to RF plasma, UV irradiation from a mercury vapor lamp enhanced degradation significantly. A lamp without power supply also enhanced degradation since weak UV light was emitted weakly from the lamp due to the excitation of mercury vapor by stray RF power. Such an enhancement is explained by the fact that after hydrogen peroxide is produced via the recombination process of OH radicals around the plasma, OH radicals reproduced from hydrogen peroxide via the photolysis process degrade methylene blue.

Temporal and spatial dynamics of laser-induced aluminum plasma in argon background at atmospheric pressure: Interplay with the ambient gas

International Nuclear Information System (INIS)

Ma, Q.L.; Motto-Ros, V.; Lei, W.Q.; Boueri, M.; Bai, X.S.; Zheng, L.J.; Zeng, H.P.; Yu, J.

2010-01-01

Laser ablation in background gas implies supplementary complexities with respect to what happens in the vacuum. It is however essential to understand in detail the involved mechanisms for a number of applications requiring the ablation to be performed in an ambient gas at relative high pressure, such as pulsed-laser deposition, or laser-induced breakdown spectroscopy. In this paper, the expansion of a vapor plume ablated from an aluminum target into an argon gas at atmospheric pressure is experimentally investigated using time- and space-resolved emission spectroscopy. The obtained results provide a detailed description of the interplay between the vapor and the gas. The electron density, the temperature and the number densities (and therefore the partial pressures) of aluminum vapor and argon gas have been measured in and surrounding the vapor plume. Our observations show a confinement of the vapor plume by the gas, which is expected as predicted by the usual hydrodynamics models. The result is a plasma core with quite uniform distributions in electron density, temperature and number densities. Such plasma core presents an ideal emission source for spectroscopic applications. It is however evidenced by our observations that a large amount of argon is mixed into the aluminum plume in the plasma core, which invalidates in the experimental conditions that we used, the hydrodynamic 'piston' model where the background gas is pushed out by the shock wave surrounding the vapor plume. Instead, other mechanisms such as laser-supported detonation wave should play important roles in the early stage of the expansion of the plasma for the determination of its morphology at longer delays.

Study of plasma off-gas treatment from spent ion exchange resin pyrolysis.

Science.gov (United States)

Castro, Hernán Ariel; Luca, Vittorio; Bianchi, Hugo Luis

2017-03-23

Polystyrene divinylbenzene-based ion exchange resins are employed extensively within nuclear power plants (NPPs) and research reactors for purification and chemical control of the cooling water system. To maintain the highest possible water quality, the resins are regularly replaced as they become contaminated with a range of isotopes derived from compromised fuel elements as well as corrosion and activation products including 14 C, 60 Co, 90 Sr, 129 I, and 137 Cs. Such spent resins constitute a major proportion (in volume terms) of the solid radioactive waste generated by the nuclear industry. Several treatment and conditioning techniques have been developed with a view toward reducing the spent resin volume and generating a stable waste product suitable for long-term storage and disposal. Between them, pyrolysis emerges as an attractive option. Previous work of our group suggests that the pyrolysis treatment of the resins at low temperatures between 300 and 350 °C resulted in a stable waste product with a significant volume reduction (>50%) and characteristics suitable for long-term storage and/or disposal. However, another important issue to take into account is the complexity of the off-gas generated during the process and the different technical alternatives for its conditioning. Ongoing work addresses the characterization of the ion exchange resin treatment's off-gas. Additionally, the application of plasma technology for the treatment of the off-gas current was studied as an alternative to more conventional processes utilizing oil- or gas-fired post-combustion chambers operating at temperatures in excess of 1000 °C. A laboratory-scale flow reactor, using inductively coupled plasma, operating under sub-atmospheric conditions was developed. Fundamental experiments using model compounds have been performed, demonstrating a high destruction and removal ratio (>99.99%) for different reaction media, at low reactor temperatures and moderate power consumption

Problem of the lithium peroxide thermal stability

International Nuclear Information System (INIS)

Nefedov, R A; Ferapontov, Yu A; Kozlova, N P

2016-01-01

The behavior of lithium peroxide and lithium peroxide monohydrate samples under heating in atmospheric air was studied by the method of thermogravimetric analysis (TGA) and differential thermal analysis (DTA). It was found that in the temperature range of 32°C to 82°C the interaction of lithium peroxides and steam with the formation of lithium peroxide monohydrate occurs, which was confirmed chemically and by X-ray Single-qualitative analysis. It was experimentally found that lithium peroxide starts to decompose into the lithium oxide and oxygen in the temperature range of 340 ÷ 348°C. It was established that the resulting thermal decomposition of lithium oxide, lithium peroxide at the temperature of 422°C melts with lithium carbonate eutecticly. The manifestation of polymorphism was not marked(seen or noticed) under the heating of studied samples of lithium peroxide and lithium peroxide monohydrate in the temperature range of 25°C ÷ 34°C. (paper)

Performance evaluation of non-thermal plasma injection for elemental mercury oxidation in a simulated flue gas

Energy Technology Data Exchange (ETDEWEB)

An, Jiutao; Shang, Kefeng; Lu, Na [Institute of Electrostatics and Special Power, Dalian University of Technology, Dalian 116024 (China); Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education of the People' s Republic of China, Dalian 116024 (China); Jiang, Yuze [Shandong Electric Power Research Institute, Jinan 250002 (China); Wang, Tiecheng [Institute of Electrostatics and Special Power, Dalian University of Technology, Dalian 116024 (China); Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education of the People' s Republic of China, Dalian 116024 (China); Li, Jie, E-mail: lijie@dlut.edu.cn [Institute of Electrostatics and Special Power, Dalian University of Technology, Dalian 116024 (China); Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education of the People' s Republic of China, Dalian 116024 (China); Wu, Yan [Institute of Electrostatics and Special Power, Dalian University of Technology, Dalian 116024 (China); Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education of the People' s Republic of China, Dalian 116024 (China)

2014-03-01

Graphical abstract: - Highlights: • The use of non-thermal plasma injection approach to oxidize Hg{sup 0} in simulated flue gas at 110 °C was studied. • A high Hg{sup 0} oxidation efficiency was observed in the mixed flue gas that included O{sub 2}, H{sub 2}O, SO{sub 2}, NO and HCl. • Chemical and physical processes (e.g., ozone, N{sub 2} metastable states and UV-light) contributed to Hg{sup 0} oxidation. • Mercury species mainly existed in the form of HgO(s) adhering to the suspended aerosols in the gas-phase. - Abstract: The use of non-thermal plasma (NTP) injection approach to oxidize elemental mercury (Hg{sup 0}) in simulated flue gas at 110 °C was studied, where a surface discharge plasma reactor (SDPR) inserted in the simulated flue duct was used to generate and inject active species into the flue gas. Approximately 81% of the Hg{sup 0} was oxidized and 20.5 μg kJ{sup −1} of energy yield was obtained at a rate of 3.9 J L{sup −1}. A maximal Hg{sup 0} oxidation efficiency was found with a change in the NTP injection air flow rate. A high Hg{sup 0} oxidation efficiency was observed in the mixed flue gas that included O{sub 2}, H{sub 2}O, SO{sub 2}, NO and HCl. Chemical and physical processes (e.g., ozone, N{sub 2} metastable states and UV-light) were found to contribute to Hg{sup 0} oxidation, with ozone playing a dominant role. The deposited mercury species on the internal surface of the flue duct was analyzed using X-ray photoelectron spectroscopy (XPS) and electronic probe microanalysis (EPMA), and the deposit was identified as HgO. The mercury species is thought to primarily exist in the form of HgO(s) by adhering to the suspended aerosols in the gas-phase.

Plasma properties of a modified beam-plasma type ion source

International Nuclear Information System (INIS)

Ishikawa, Junzo; Sano, Fumimichi; Tsuji, Hiroshi; Ektessabi, A.M.; Takagi, Toshinori

1978-01-01

The properties of the plasma produced by beam-plasma discharge were experimentally investigated. The ion source used for this work consists of three parts, that is, the ion-extracting region with an electron gun, the drift space and the collector region. Primary and secondary electron beams are injected in to the drift tube. The interaction between plasma and these electron beams causes production of high density plasma by virtue of the beam-plasma discharge. The gas inlet is located in the middle of the drift tube, so that the gas conductance is high. The energy of the primary and secondary electron beams is transferred to that microwaves through beam-plasma interaction. The microwaves heat the plasma electrons by the cyclotron resonance or other mechanism. The amount of the energetic plasma electrons is much larger than that of the beam electrons, so that neutral gas is ionized. The density of the produced plasma is 10 2 or 10 3 times as large as the plasma produced by impact ionization. With a probe located in the middle of the drift tube, the plasma density and the electron temperature can be measured, and the power and spectra of the microwaves can be detected. The microwave oscillation, the primary electron beam characteristics, and the gas pressure characteristics were studied. Larger current of the high energy primary of secondary electron beam is required for the effective discharge. The ion source has to be operated at the minimum gas pressure. The length of beam-plasma interaction and the magnetic field intensity in the drift tube are also important parameters. (Kato, T.)

[Experimental investigation of laser plasma soft X-ray source with gas target].

Science.gov (United States)

Ni, Qi-liang; Gong, Yan; Lin, Jing-quan; Chen, Bo; Cao, Jian-lin

2003-02-01

This paper describes a debris-free laser plasma soft X-ray source with a gas target, which has high operating frequency and can produce strong soft X-ray radiation. The valve of this light source is drived by a piezoelectrical ceramic whose operating frequency is up to 400 Hz. In comparison with laser plasma soft X-ray sources using metal target, the light source is debris-free. And it has higher operating frequency than gas target soft X-ray sources whose nozzle is controlled by a solenoid valve. A channel electron multiplier (CEM) operating in analog mode is used to detect the soft X-ray generated by the laser plasma source, and the CEM's output is fed to to a charge-sensitive preamplifier for further amplification purpose. Output charges from the CEM are proportional to the amplitude of the preamplifier's output voltage. Spectra of CO2, Xe and Kr at 8-14 nm wavelength which can be used for soft X-ray projection lithography are measured. The spectrum for CO2 consists of separate spectral lines originate mainly from the transitions in Li-like and Be-like ions. The Xe spectrum originating mainly from 4d-5f, 4d-4f, 4d-6p and 4d-5p transitions in multiply charged xenon ions. The spectrum for Kr consists of separate spectral lines and continuous broad spectra originating mainly from the transitions in Cu-, Ni-, Co- and Fe-like ions.

Combined plasma gas-phase synthesis and colloidal processing of InP/ZnS core/shell nanocrystals

OpenAIRE

Hue Ryan; Gladfelter Wayne; Gresback Ryan; Kortshagen Uwe

2011-01-01

Abstract Indium phosphide nanocrystals (InP NCs) with diameters ranging from 2 to 5 nm were synthesized with a scalable, flow-through, nonthermal plasma process at a rate ranging from 10 to 40 mg/h. The NC size is controlled through the plasma operating parameters, with the residence time of the gas in the plasma region strongly influencing the NC size. The NC size distribution is narrow with the standard deviation being less than 20% of the mean NC size. Zinc sulfide (ZnS) shells were grown ...

Plasma cleaning of beamline optical components: Contamination and gas composition effects

International Nuclear Information System (INIS)

Rosenberg, R.A.; Smith, J.A.; Wallace, D.J.

1992-01-01

We have initiated a program to study the impact of gas composition on the carbon removal rate during plasma cleaning of optical components, and of possible contamination due to the plasma processing. The measurements were performed in a test chamber designed to simulate the geometry of the grating/Codling mirror section of a Grasshopper monochromator. Removal rates were determined for a direct-current (dc) (Al electrode) discharge using a quartz crystal microbalance coated with polymethylmethacrylate, located at the position of the grating. Auger electron spectroscopy analysis of strateg- ically located, gold-coated stainless steel samples was employed to determine contamination. The relative removal rates of the gases studied were 3% C 2 F 6 /O 2 much-gt O 2 +H 2 O>O 2 ∼N 2 O>H 2 >N 2 . Although the C 2 F 6 /O 2 gas mixture showed a 20 times greater removal rate than its nearest competitor, it also caused significant contamination to occur. Contamination studies were performed for both dc and radio-frequency (rf) discharges. For the dc discharge we found that great care must be taken in order to avoid Al contamination; for the rf discharge, significant Fe contamination was observed

Modelling chemical reactions in dc plasma inside oxygen bubbles in water

International Nuclear Information System (INIS)

Takeuchi, N; Ishii, Y; Yasuoka, K

2012-01-01

Plasmas generated inside oxygen bubbles in water have been developed for water purification. Zero-dimensional numerical simulations were used to investigate the chemical reactions in plasmas driven by dc voltage. The numerical and experimental results of the concentrations of hydrogen peroxide and ozone in the solution were compared with a discharge current between 1 and 7 mA. Upon increasing the water vapour concentration inside bubbles, we saw from the numerical results that the concentration of hydrogen peroxide increased with discharge current, whereas the concentration of ozone decreased. This finding agreed with the experimental results. With an increase in the discharge current, the heat flux from the plasma to the solution increased, and a large amount of water was probably vaporized into the bubbles.

Modelling chemical reactions in dc plasma inside oxygen bubbles in water

Science.gov (United States)

Takeuchi, N.; Ishii, Y.; Yasuoka, K.

2012-02-01

Plasmas generated inside oxygen bubbles in water have been developed for water purification. Zero-dimensional numerical simulations were used to investigate the chemical reactions in plasmas driven by dc voltage. The numerical and experimental results of the concentrations of hydrogen peroxide and ozone in the solution were compared with a discharge current between 1 and 7 mA. Upon increasing the water vapour concentration inside bubbles, we saw from the numerical results that the concentration of hydrogen peroxide increased with discharge current, whereas the concentration of ozone decreased. This finding agreed with the experimental results. With an increase in the discharge current, the heat flux from the plasma to the solution increased, and a large amount of water was probably vaporized into the bubbles.

Characterization of a plasma produced using a high power laser with a gas puff target for x-ray laser experiments

International Nuclear Information System (INIS)

Fiedorowicz, H.; Bartnik, A.; Gac, K.; Parys, P.; Szczurek, M.; Tyl, J.

1995-01-01

A high temperature, high density plasma can be produced by using a nanosecond, high-power laser with a gas puff target. The gas puff target is formed by puffing a small amount of gas from a high-pressure reservoir through a nozzle into a vacuum chamber. In this paper we present the gas puff target specially designed for x-ray laser experiments. The solenoid valve with the nozzle in the form of a slit 0.3-mm wide and up to 40-mm long, allows to form an elongated gas puff suitable for the creation of an x-ray laser active medium by its perpendicular irradiation with the use of a laser beam focused to a line. Preliminary results of the experiments on the laser irradiation of the gas puff targets, produced by the new valve, show that hot plasma suitable for x-ray lasers is created

The application of dynamic method for the temperature measurement of gas destruction in a plasma reactor

International Nuclear Information System (INIS)

Ryszard, Sarba

2009-01-01

This paper presents an experimental and theoretical study of the conversion of measuring probe temperature into hot gas temperature. The author gives a solution to the problem of a destruction temperature measurement in a plasma reactor. The temperature conversion is based on the thermodynamic similarity theory and statistical thermodynamics verification. The experimental measurements of the hot gas temperature have been made in the place where it considerably exceeds the melting point of the measuring probe material. The heat exchange phenomenon on the measuring probe's surface with the hot gas surrounding it is described by a forced convection equation. An analysis has been made of the heat flowing in and out of the measuring probe. The experimental part of the paper includes: an experimental measurement of gas velocity by means of luminous particles, a hot gas measurement for one distance from a nozzle and different diameters of the measuring probe, as well as different probing velocities. Numerical simulations have been made of the temperature distribution in a plasma jet. The experimental results are congruent with theoretical predictions. The aim of this research is a contribution to the structuring of a mathematical model of mass and energy balance in the processes of NHF 2 CL waste destruction.

Comparison between gas puffing and supersonic molecular beam injection in plasma density feedback experiments in EAST

International Nuclear Information System (INIS)

Zheng, Xingwei; Li, Jiangang; Hu, Jiansheng; Li, Jiahong; Ding, Rui; Cao, Bin; Wu, Jinhua

2013-01-01

To achieve desirable plasma density control, a supersonic molecular beam injection (SMBI) feedback control system has been developed recently for the EAST tokamak. The performance of the SMBI and gas puffing (GP) feedback systems were used and compared. The performance of pulse width mode is better than that of pulse amplitude mode when GP was used for density feedback control. During one-day experiments, the variation of gas input and wall retention can be clarified into two stages. In the first stage the retention ratio is as high as 80–90%, and the gas input is about an order of 10 22 D 2 . However, in the second stage, the retention ratio is at a range of 50–70%. The gas input of a single discharge is small and the net wall retention grows slowly. The results of the SMBI feedback control experiment was analyzed. The shorter delay time of SMBI makes it faster at feeding back control the plasma density. The result showed that, compared with GP, the gas input of SMBI was decreased ∼30% and the wall retention was reduced ∼40%. This shows SMBI's advantage for the long pulse high density discharges in EAST. (paper)

Plasma device

International Nuclear Information System (INIS)

Thode, L.E.

1981-01-01

A relativistic electron beam generator or accelerator produces a high-voltage electron beam which is modulated to initiate electron bunching within the beam which is then applied to a high-density target plasma which typically comprises DT, DD, or similar thermonuclear gas at a density of 10 17 to 10 20 electrons per cubic centimeter. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region of the high-density plasma target. The high-temperature plasma can be used to heat a high Z material to generate radiation. Alternatively, a tunable radiation source is produced by using a moderate Z gas or a mixture of high Z and low Z gas as the target plasma. (author)

Influence of spray parameters on the microstructure and mechanical properties of gas-tunnel plasma sprayed hydroxyapatite coatings

International Nuclear Information System (INIS)

Morks, M.F.; Kobayashi, Akira

2007-01-01

For biomedical applications, hydroxyapatite (HA) coatings were deposited on 304 stainless steel substrate by using a gas tunnel type plasma spraying process. The influences of spraying distances and plasma arc currents on the microstructure, hardness and adhesion properties of HA coatings were investigated. Microstructure observation by SEM showed that HA coatings sprayed at low plasma power have a porous structure and poor hardness. HA coatings sprayed at high plasma power and short spraying distance are characterized by good adhesion and low porosity with dense structure. Hardness increased for HA coatings sprayed at shorter spraying distance and higher plasma power, mainly due to the formation of dense coatings

Pulmonary gas exchange impairment following tourniquet deflation: a prospective, single-blind clinical trial.

Science.gov (United States)

Lin, Lina; Wang, Liangrong; Bai, Yu; Zheng, Liupu; Zhao, Xiyue; Xiong, Xiangqing; Jin, Lida; Ji, Wei; Wang, Wantie

2010-06-09

The tourniquet has been considered as a recognized cause of limb ischemia/reperfusion injury in orthopedic surgery resulting in a transient neutrophil, monocyte activation, and enhanced neutrophil transendothelial migration with potential remote tissue injury. This study investigated the effect of unilateral tourniquet application within a safe time limit on pulmonary function and the roles of lipid peroxidation and systemic inflammatory response. Thirty patients undergoing unilateral lower extremity surgery with or without tourniquet were equally divided into a control group with no tourniquet (Group C) and a tourniquet (Group T). Arterial partial pressure of oxygen (P(a)O(2)), arterial-alveolar oxygen tension ratio (a/A ratio), alveolar-arterial oxygen difference (A-aDO(2)) and respiratory index, plasma malondialdehyde, serum interleukin (IL) -6 and IL-8 levels were measured immediately before and 1 hour after tourniquet inflation/operation beginning, 0.5, 2, 6, and 24 hours after tourniquet deflation/operation ending. The results represented no significant changes in Group C with regard to either blood gas variables or levels of circulating mediators, while blood gas variable changes of greater A-aDO(2) and respiratory index and lower PaO2 and a/A ratio were shown at 6 hours following tourniquet deflation. The levels of malondialdehyde, IL-6, and IL-8 were increased over baseline values from 2 to 24 hours following tourniquet deflation in Group T. We concluded that tourniquet application within a safe time limit may cause pulmonary gas exchange impairment several hours after tourniquet deflation, where lipid peroxidation and systemic inflammatory response may be involved. Copyright 2010, SLACK Incorporated.

The effects of UV irradiation and gas plasma treatment on living mammalian cells and bacteria: a comparative approach

NARCIS (Netherlands)

Sosnin, E.A.; Stoffels - Adamowicz, E.; Erofeev, M.V.; Kieft, I.E.; Kunts, S.E.

2004-01-01

Living mammalian cells and bacteria were exposed to irradiation from narrow-band UV lamps and treated with a nonthermal gas plasma (plasma needle). The model systems were: Chinese Hamster Ovary (CHO-K1) cells (fibroblasts) and Escherichia Coli bacteria. UV irradiation can lead to cell death

Endothelial cell behaviour on gas-plasma-treated PLA surfaces: the roles of surface chemistry and roughness.

Science.gov (United States)

Shah, Amita; Shah, Sarita; Mani, Gopinath; Wenke, Joseph; Agrawal, Mauli

2011-04-01

Glow-discharge gas-plasma (GP) treatment has been shown to induce surface modifications such that cell adhesion and growth are enhanced. However, it is not known which gas used in GP treatment is optimal for endothelial cell function. Polylactic acid (PLA) films treated oxygen, argon, or nitrogen GP were characterized using contact angles, scanning electron microscopy, atomic force microscopy, optical profilometry, and x-ray photoelectron spectroscopy. All three GP treatments decreased the carbon atomic concentration and surface roughness and increased the oxygen atomic concentration. Human umbilical vein endothelial cells were cultured on the PLA films for up to 7 days. Based on proliferation and live/dead assays, surface chemistry was shown to have the greatest effect on the attachment, proliferation, and viability of these cells, while roughness did not have a significant influence. Of the different gases, endothelial cell viability, attachment and proliferation were most significantly increased on PLA surfaces treated with oxygen and argon gas plasma. Copyright © 2010 John Wiley & Sons, Ltd.

ORNL neutral gas shielding model for pellet-plasma interactions

International Nuclear Information System (INIS)

Milora, S.L; Foster, C.A.

1977-05-01

A revised neutral molecule ablation model is derived to describe the evaporation of a solid hydrogen pellet in a tokamak plasma. The approach taken is based on the theory of Parks, Turnbull, and Foster who postulate that a cloud of molecular hydrogen surrounding the pellet shields the surface from incoming energetic electrons and, in so doing, regulates the evaporation rate. This treatment differs from an earlier model in that the hydrodynamic behavior of the molecular cloud is treated in a self-consistent manner. Numerical solutions of the fluid dynamic equations, which include the effects of strong electron heating locally in the gas, reveal that the flow of material away from the pellet is initially retarded by the heating and then rapidly accelerated and rarefied. This behavior is more pronounced for higher temperature plasmas and the net effect is that pellet lifetimes are prolonged slightly by including the heating effects. A comparison is made with the results of the recent pellet injection experiments on ORMAK and a simple injection depth scaling law is derived

Analysis of hysteresis characteristics and low frequency oscillation in gas discharge plasma

International Nuclear Information System (INIS)

Matsunaga, Yasushi; Kato, Tomokazu

1997-01-01

Hysteresis of gas discharge plasma and nonlinear oscillation of low frequency, caused by the trapped ion, are analyzed. Mainly, the hysteresis and emergence of multiple-steady states are discussed by a simple model of chemical-reaction system. It is shown that a function describing the energy balance has three different real roots. The condition for plural roots depends on the ratio of the bulk energy increase to the surface energy loss of plasma. The criterion contains the non-thermodynamic variables such as conductivity and surface quantities. Examination of stabilities of three-obtained solutions by using linear analysis of differential equations manifests that a root represents a saddle point and other two roots represent stable points. (author)

User's manual of self learning gas puffing system for plasma density control

International Nuclear Information System (INIS)

Tanahashi, S.

1989-04-01

Pre-programmed gas puffing is often used to get adequet plasma density wave forms in the pulse operating devices for fusion experiments. This method has a defect that preset values have to be adjusted manually in accordance with changes of out gassing rate in successive shots. In order to remove this defect, a self learning system has been developed so as to keep the plasma density close to a given reference waveform. After a few succesive shots, it accomplishes self learning and is ready to keep up with a gradual change of the wall condition. This manual gives the usage of the system and the program list written in BASIC and ASSEMBLER languages. (author)

Determination of clebopride in plasma by capillary gas chromatography-negative-ion chemical ionization mass spectrometry.

Science.gov (United States)

Robinson, P R; Jones, M D; Maddock, J

1988-11-18

A procedure for the analysis of clebopride in plasma using capillary gas chromatography-negative-ion chemical ionization mass spectrometry has been developed. Employing an ethoxy analogue as internal standard, the two compounds were extracted from basified plasma using dichloromethane. Subsequent reaction with heptafluorobutyryl imidazole produced volatile monoheptafluorobutyryl derivatives whose ammonia negative-ion mass spectra proved ideal for selected-ion monitoring. The recovery of clebopride from plasma at 0.536 nmol/l was found to be 85.5 +/- 0.9% (n = 3) whilst measurement down to 0.268 nmol/l was possible with a coefficient of variation of 7.9%. Plasma levels of the compound are reported in two volunteers following ingestion of 1 mg of clebopride as the malate salt.

Spectroscopic studies of europium-tetracyclines complexes and their applications in detection of hydrogen peroxide and urea peroxide

International Nuclear Information System (INIS)

Grasso, Andrea Nastri

2010-01-01

In this work were studied the spectroscopic properties of trivalent europium ion complexed with components of tetracycline family, chlorotetracycline, oxytetracycline and metacycline, in the presence of hydrogen peroxide and urea peroxide. Optical parameters were obtained such as absorption, emission, lifetime and calibration curves were constructed for luminescence spectra. Experiments were carried out with both inorganic compounds and europium-tetracyclines complexes in order to verify possible interferences. Studies for glucose determination were also described using europium-tetracyclines complexes as biosensors. Results show that europium tetracyclines complexes emit a narrow band in the visible region and, in the presence of hydrogen peroxide or urea peroxide there is a greater enhancement in their luminescence and lifetime. Thus, europium-tetracyclines complexes studied can be used as biosensors for hydrogen and urea peroxides determination as a low cost and room temperature method. An indirect method for glucose determination was studied by adding glucose oxidase enzyme in europium-tetracyclines complex in the presence of glucose promoting as product hydrogen peroxide. (author)

Ultraviolet versus infrared: Effects of ablation laser wavelength on the expansion of laser-induced plasma into one-atmosphere argon gas

International Nuclear Information System (INIS)

Ma Qianli; Motto-Ros, Vincent; Laye, Fabrice; Yu Jin; Lei Wenqi; Bai Xueshi; Zheng Lijuan; Zeng Heping

2012-01-01

Laser-induced plasma from an aluminum target in one-atmosphere argon background has been investigated with ablation using nanosecond ultraviolet (UV: 355 nm) or infrared (IR: 1064 nm) laser pulses. Time- and space-resolved emission spectroscopy was used as a diagnostics tool to have access to the plasma parameters during its propagation into the background, such as optical emission intensity, electron density, and temperature. The specific feature of nanosecond laser ablation is that the pulse duration is significantly longer than the initiation time of the plasma. Laser-supported absorption wave due to post-ablation absorption of the laser radiation by the vapor plume and the shocked background gas plays a dominant role in the propagation and subsequently the behavior of the plasma. We demonstrate that the difference in absorption rate between UV and IR radiations leads to different propagation behaviors of the plasma produced with these radiations. The consequence is that higher electron density and temperature are observed for UV ablation. While for IR ablation, the plasma is found with lower electron density and temperature in a larger and more homogenous axial profile. The difference is also that for UV ablation, the background gas is principally evacuated by the expansion of the vapor plume as predicted by the standard piston model. While for IR ablation, the background gas is effectively mixed to the ejected vapor at least hundreds of nanoseconds after the initiation of the plasma. Our observations suggest a description by laser-supported combustion wave for the propagation of the plasma produced by UV laser, while that by laser-supported detonation wave for the propagation of the plasma produced by IR laser. Finally, practical consequences of specific expansion behavior for UV or IR ablation are discussed in terms of analytical performance promised by corresponding plasmas for application with laser-induced breakdown spectroscopy.

On-line Automated Sample Preparation-Capillary Gas Chromatography for the Analysis of Plasma Samples.

NARCIS (Netherlands)

Louter, A.J.H.; van der Wagt, R.A.C.A.; Brinkman, U.A.T.

1995-01-01

An automated sample preparation module, (the automated sample preparation with extraction columns, ASPEC), was interfaced with a capillary gas chromatograph (GC) by means of an on-column interface. The system was optimised for the determination of the antidepressant trazodone in plasma. The clean-up

21 CFR 529.1150 - Hydrogen peroxide.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrogen peroxide. 529.1150 Section 529.1150 Food... DRUGS, FEEDS, AND RELATED PRODUCTS CERTAIN OTHER DOSAGE FORM NEW ANIMAL DRUGS § 529.1150 Hydrogen peroxide. (a) Specifications. Each milliliter of solution contains 396.1 milligrams (mg) hydrogen peroxide...

Determination of Trace Anions in Concentrated Hydrogen Peroxide by Direct Injection Ion Chromatography with Conductivity Detection after Pt-Catalyzed On-Line Decomposition

International Nuclear Information System (INIS)

Kim, Do Hee; Lee, Bo Kyung; Lee, Dong Soo

1999-01-01

A method has been developed for the determination of trace anion impurities in concentrated hydrogen peroxide. The method involves on-line decomposition of hydrogen peroxide, ion chromatographic separation and subsequent suppressed-type conductivity detection. H 2 O 2 is decomposed in Pt-catalyst filled Gore-Tex membrane tubing and the resulting aqueous solution containing analytes is introduced to the injection valve of an ion chromatograph for periodic determinations. The oxygen gas evolving within the membrane tubing escapes freely through the membrane wall causing no problem in ion chromatographic analysis. Decomposition efficiency is above 99.99% at a flow rate of 0.4mL/min for a 30% hydrogen peroxide concentration. Analytes are quantitatively retained. The analysis results for several brands of commercial hydrogen peroxides are reported

Radiative response on massive noble gas injection for Runaway suppression in disruptive plasmas

International Nuclear Information System (INIS)

Reiter, Bernhard

2010-01-01

The most direct way to avoid the formation of a relativistic electron beam under the influence of an electric field in a highly conducting plasma, is to increase the electron density to a value, where the retarding collisional force balances the accelerating one. In a disruptive tokamak plasma, rapid cooling induces a high electric field, which could easily violate the force balance and push electrons into the relativistic regime. Such relativistic electrons, the so-called runaways, accumulate many MeV's and can cause substantial damage when they hit the wall. This thesis is based on the principle of rapidly fueling the plasma for holding the force balance even under the influence of high electric fields typical for disruptions. The method of injecting high amounts of noble gas particles into the plasma from a close distance is put into practice in the ASDEX Upgrade fusion test facility. In the framework of this thesis, a multi-channel photometer system based on 144 AXUV detectors in a toroidal stereo measurement setup was built. It kept its promise to provide new insights into the transport mechanisms in a disruptive plasma under the influence of strong radiative interaction dynamics between injected matter and the hot plasma.

Specific features of peroxide stress in children permanently exposed to low-intensity radiation

International Nuclear Information System (INIS)

Durnov, L.A.; Bajkova, V.N.; Mayakova, S.A.; Polyakov, V.G.; Kolosov, E.A.; Dumbrajs, K.O.; Gracheva, I.V.; Zakharova, N.V.; Leonidova, Yu.A.; Romanova, L.F.

2000-01-01

To study the peculiarities of peroxide stress in children residing at the territories with chronic low-intensity radiation effects, the investigation was performed of tyrosine level, indices of the intensity of free radical lipid peroxidation and antioxidant system status in children and teenagers living in Sverdlovsk and Kolpnyansk districts of the Orel region contaminated due to the Chernobyl accident. Regions mentioned are characterized by low-intensity contamination with radionuclides (mainly 90 Sr, 131 I, 137 Cs), 25% an increase in tyrosine content, 1.8 times in malonic dial, 25-40 % in catalase and superoxide dismutase activity was revealed in blood plasma. Contents of A and E vitamins, glutathione and glutathione-depending enzymes are decreased. It is recommended to observe children health in regions contaminated as a result of the Chernobyl accident and correct failed redox processes using antioxidative vitamins [ru

Feasibility, strategy, methodology, and analysis of probe measurements in plasma under high gas pressure

Science.gov (United States)

Demidov, V. I.; Koepke, M. E.; Kurlyandskaya, I. P.; Malkov, M. A.

2018-02-01

This paper reviews existing theories for interpreting probe measurements of electron distribution functions (EDF) at high gas pressure when collisions of electrons with atoms and/or molecules near the probe are pervasive. An explanation of whether or not the measurements are realizable and reliable, an enumeration of the most common sources of measurement error, and an outline of proper probe-experiment design elements that inherently limit or avoid error is presented. Additionally, we describe recent expanded plasma-condition compatibility for EDF measurement, including in applications of large wall probe plasma diagnostics. This summary of the authors’ experiences gained over decades of practicing and developing probe diagnostics is intended to inform, guide, suggest, and detail the advantages and disadvantages of probe application in plasma research.

Revised neutral gas shielding model for pellet ablation - combined neutral and plasma shielding

International Nuclear Information System (INIS)

Houlberg, W.A.; Schuresko, D.D.; Attenberger, S.E.

1986-01-01

The ablation and penetration of pellets in early ORMAK and ISX-A experiments were reliably predicted by the neutral gas shielding model of Milora and Foster. These experiments demonstrated that the principle components of the model - a self-generated shield which reduces the heat flux at the plasma surface - were correct. In more recent experiments with higher temperature plasmas, this model consistently predicts greater penetration than observed in the experiments. Upgarding known limitations of the original model brings the predicted and observed penetration values into agreement. These improvements include: (1) treating the incident electrons as having distribution in energy rather than being monoenergetic; (2) including the shielding effects of cold, dense plasma extending along the magnetic field outside the neutral shield; and (3) modifying the finite plasma, self-limiting incident heat flux so that it represents a collisionless plasma limit rather than a collisional limit. Comparisons are made between the models for a selection of ISX-B Alcator-C, and TFTR shots. The net effect of the changes in the model is an increase in pellet ablation rates and decrease in penetration for current and future experiments

Combined plasma gas-phase synthesis and colloidal processing of InP/ZnS core/shell nanocrystals

Science.gov (United States)

Gresback, Ryan; Hue, Ryan; Gladfelter, Wayne L.; Kortshagen, Uwe R.

2011-12-01

Indium phosphide nanocrystals (InP NCs) with diameters ranging from 2 to 5 nm were synthesized with a scalable, flow-through, nonthermal plasma process at a rate ranging from 10 to 40 mg/h. The NC size is controlled through the plasma operating parameters, with the residence time of the gas in the plasma region strongly influencing the NC size. The NC size distribution is narrow with the standard deviation being less than 20% of the mean NC size. Zinc sulfide (ZnS) shells were grown around the plasma-synthesized InP NCs in a liquid phase reaction. Photoluminescence with quantum yields as high as 15% were observed for the InP/ZnS core-shell NCs.

Megawatt low-temperature DC plasma generator with divergent channels of gas-discharge tract

Science.gov (United States)

Gadzhiev, M. Kh.; Isakaev, E. Kh.; Tyuftyaev, A. S.; Yusupov, D. I.; Sargsyan, M. A.

2017-04-01

We have developed and studied a new effective megawatt double-unit generator of low-temperature argon plasma, which belongs to the class of dc plasmatrons and comprises the cathode and anode units with divergent gas-discharge channels. The generator has an efficiency of about 80-85% and ensures a long working life at operating currents up to 4000 A.

Effect of helium plasma gas flow rate on the properties of WC-12 wt.%Co coatings sprayed by atmospheric plasma

Directory of Open Access Journals (Sweden)

Mihailo R. Mrdak

2014-06-01

Full Text Available The cermet coatings of WC-12wt.%Co are extensively used to improve the wear resistance of a wide range of technical components. This paper analyses the influence of the plasma gas flow of helium on the microstructure and mechanical properties of WC-12wt.%Co coatings deposited by plasma spraying at atmospheric pressure (APS. In order to obtain homogeneous and denser coatings, three different flows of He ( 8 l/min., 16 l/min. and 32 l/min were used in the research. With the application of He, coatings achieved higher values of hardness due to less degradation of the primary WC carbides. The main goal was to deposit dense and homogeneous layers of WC-12wt.%Co coatings with improved wear resistance for different applications. The test results of the microstructure of the layers were evaluated under a light microscope. The analysis of the microstructure and the mechanical properties of the deposited layers was made in accordance with the standard of Pratt-Whitney. The morphology of the powder particles and the microstructure of the best coating was examined on the SEM (scanning electron microscope. The evaluation of the mechanical properties of the layers was done by applying the HV0.3 method for microhardness testing and by applying tensile testing to test the bond strength. The research has shown that the flow of He plasma gas significantly affects the microstructure, the mechanical properties and the structure of WC-12 wt.%Co coatings.

Influence of ph on corrosion control of carbon steel by peroxide injection in sour water

Energy Technology Data Exchange (ETDEWEB)

Vieira, Martins Magda; Baptista, Walmar; Joia, Carlos Jose Bandeira de Mello [PROTEMP - PETROBRAS/CENPES, Cidade Universitaria, Quadra 7, Rio de Janeiro, CEP 21949-900 (Brazil); Ponciano, Gomes Jose Antonio da Cunha [Departamento de Engenharia Metalurgica e de Materiais-COPPE/UFRJ, Cidade Universitaria, Rio de Janeiro (Brazil)

2004-07-01

Sour hydrogen damage is considered the most important corrosive process in the light-ends recovery section of Fluid Catalytic Cracking Units (FCCU). Corrosion in this condition is due to heavy gas oil that originates great amount of contaminants, such as H{sub 2}S, NH{sub 3} and HCN. Hydrogen absorption is promoted by the presence of free cyanides in the environment. The attenuation of this process requires the use of some inhibitors, such as oxygen, hydrogen peroxide (H{sub 2}O{sub 2}) or commercial polysulfides. The effect of these compounds is to neutralize free cyanides (CN{sup -}) into thio-sulfides (SCN{sup -}). When peroxide injection is selected, cyanide concentration in sour water has been used as key parameter to start the peroxide introduction. However, the importance of pH in this system has been pointed out by many authors. The aim of this work is to investigate the influence of pH when peroxide injection is carried out in less alkaline conditions of sour water. Electrochemical techniques - like anodic polarization and hydrogen permeation tests - and weight loss measurements were used to evaluate the effectiveness of corrosion control of carbon steel. It was concluded that at pH 7.5 peroxide injection can drive to an increment of the corrosion rate. Besides that, it was concluded that hydrogen permeation into the metal is promoted. Both detrimental effects were due to elemental sulfur generation in this pH range. The adoption of pH as a key parameter for peroxide injection is then suggested. (authors)

Hippophae rhamnoides L. Fruits Reduce the Oxidative Stress in Human Blood Platelets and Plasma

Directory of Open Access Journals (Sweden)

Beata Olas

2016-01-01

Full Text Available Effects of the phenolic fraction from Hippophae rhamnoides fruits on the production of thiobarbituric acid reactive substances (TBARS, a marker of lipid peroxidation and the generation of superoxide anion (O2-∙ in human blood platelets (resting platelets and platelets stimulated by a strong physiological agonist, thrombin were studied in vitro. We also examined antioxidant properties of this fraction against human plasma lipid peroxidation and protein carbonylation induced by a strong biological oxidant, hydrogen peroxide (H2O2 or H2O2/Fe (a donor of hydroxyl radicals. The tested fraction of H. rhamnoides (0.5– 50 µg/mL; the incubation time: 15 and 60 min inhibited lipid peroxidation induced by H2O2 or H2O2/Fe. The H. rhamnoides phenolic fraction inhibited not only plasma lipid peroxidation, but also plasma protein carbonylation stimulated by H2O2 or H2O2/Fe. Moreover, the level of O2-∙ in platelets significantly decreased. In comparative experiments, the H. rhamnoides fraction was a more effective antioxidant than aronia extract or grape seed extract (at the highest tested concentration, 50 µg/mL. The obtained results suggest that H. rhamnoides fruits may be a new, promising source of natural compounds with antioxidant and antiplatelet activity beneficial not only for healthy people, but also for those with oxidative stress-associated diseases.

Effect of a barley-vegetable soup on plasma carotenoids and biomarkers of cardiovascular disease.

Science.gov (United States)

Bacchetti, Tiziana; Tullii, Domenico; Masciangelo, Simona; Gesuita, Rosaria; Skrami, Edlira; Brugè, Francesca; Silvestri, Sonia; Orlando, Patrick; Tiano, Luca; Ferretti, Gianna

2015-07-01

Functional foods that provide benefits beyond their traditional nutritional value have attracted much interest. Aim of the study was to evaluate the nutritional and the functional properties of a frozen ready-to-eat soup containing barley and pigmented vegetables. Both glycaemic index and the glyceamic load of ready-to-eat soup were evaluated in vivo. Moreover the bioavailability of carotenoids (lutein and beta-carotene) and the effect on lipid profile and lipid peroxidation were studied in 38 volunteers whose diet was supplemented for two weeks with a daily portion (250 g) of the ready-to-eat soup. Plasma levels of carotenoids (lutein and beta-carotene) and plasma total antioxidant capacity significantly increased after 2 weeks of treatment. Furthermore, we observed a decrease in the levels of lipids (total cholesterol and low density lipoprotein-cholesterol) and of markers of lipid peroxidation (oxidized low density lipoprotein and lipid hydroperoxides) in plasma of all subjects. The glyceamic index of the product was 36, therefore it could be considered a low glyceamic index food. An accurate selection of vegetable foods results in a palatable and healthy product that provides benefits on plasma lipids and lipid peroxidation (Protocol number 211525).

The Role of Spraying Parameters and Inert Gas Shrouding in Hybrid Water-Argon Plasma Spraying of Tungsten and Copper for Nuclear Fusion Applications

Czech Academy of Sciences Publication Activity Database

Matějíček, Jiří; Kavka, Tetyana; Bertolissi, Gabriele; Ctibor, Pavel; Vilémová, Monika; Mušálek, Radek; Nevrlá, Barbara

2013-01-01

Roč. 22, č. 5 (2013), s. 744-755 ISSN 1059-9630 R&D Projects: GA MPO FR-TI2/702; GA TA ČR TA01010300 Institutional support: RVO:61389021 Keywords : plasma spraying * tungsten * copper * inert gas shrouding * water-argon plasma torch * gas shroud * hybrid plasma torch * influence of spray parameters * nuclear fusion * oxidation Subject RIV: JG - Metallurgy Impact factor: 1.491, year: 2013 http://link.springer.com/content/pdf/10.1007%2Fs11666-013-9895-x.pdf

Maternal and neonatal plasma antioxidant levels in normal pregnancy, and the relationship with fatty acid unsaturation

NARCIS (Netherlands)

Oostenbrug, G.S.; Mensink, R.P.; Al, M.D.M.; Houwelingen, A.C. van; Hornstra, G.

1998-01-01

During pregnancy, maternal plasma concentrations of the peroxidation-susceptible polyunsaturated fatty acids (polyenes) increase. In addition, the proportion of polyenes is higher in neonatal plasma than in maternal plasma. To study whether these increased amounts of polyenes affect antioxidant

High-frequency underwater plasma discharge application in antibacterial activity

International Nuclear Information System (INIS)

Ahmed, M. W.; Choi, S.; Lyakhov, K.; Shaislamov, U.; Mongre, R. K.; Jeong, D. K.; Suresh, R.; Lee, H. J.

2017-01-01

Plasma discharge is a novel disinfection and effectual inactivation approach to treat microorganisms in aqueous systems. Inactivation of Gram-negative Escherichia coli (E. coli) by generating high-frequency, high-voltage, oxygen (O_2) injected and hydrogen peroxide (H_2O_2) added discharge in water was achieved. The effect of H_2O_2 dose and oxygen injection rate on electrical characteristics of discharge and E. coli disinfection has been reported. Microbial log reduction dependent on H_2O_2 addition with O_2 injection was observed. The time variation of the inactivation efficiency quantified by the log reduction of the initial E. coli population on the basis of optical density measurement was reported. The analysis of emission spectrum recorded after discharge occurrence illustrated the formation of oxidant species (OH"•, H, and O). Interestingly, the results demonstrated that O_2 injected and H_2O_2 added, underwater plasma discharge had fabulous impact on the E. coli sterilization. The oxygen injection notably reduced the voltage needed for generating breakdown in flowing water and escalated the power of discharge pulses. No impact of hydrogen peroxide addition on breakdown voltage was observed. A significant role of oxidant species in bacterial inactivation also has been identified. Furthermore the E. coli survivability in plasma treated water with oxygen injection and hydrogen peroxide addition drastically reduced to zero. The time course study also showed that the retardant effect on E. coli colony multiplication in plasma treated water was favorable, observed after long time. High-frequency underwater plasma discharge based biological applications is technically relevant and would act as baseline data for the development of novel antibacterial processing strategies.

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.

Gas-phase evolution of Ar/H2O and Ar/CH4 dielectric barrier discharge plasmas

Science.gov (United States)

Barni, Ruggero; Riccardi, Claudia

2018-04-01

We present some experimental results of an investigation aimed to hydrogen production with atmospheric pressure plasmas, based on the use of dielectric barrier discharges, fed with a high-voltage alternating signal at frequency 30-50 kHz, in mixtures of methane or water vapor diluted in argon. The plasma gas-phase of the discharge was investigated by means of optical and electrical diagnostics. The emission spectra of the discharges was measured with a wide band spectrometer and a photosensor module, based on a photomultiplier tube. A Rogowski coil allowed to measure the electric current flowing into the circuit and a high voltage probe was employed for evaluating the voltage at the electrodes. The analysis of the signals of voltage and current shows the presence of microdischarges between the electrodes in two alternating phases during the period of oscillation of the applied voltage. The hydrogen concentration in the gaseous mixture was measured too. Besides this experimental campaign, we present also results from a numerical modeling of chemical kinetics in the gas-phase of Ar/H2O and Ar/CH4 plasmas. The simulations were conducted under conditions of single discharge to study the evolution of the system and of fixed frequency repeated discharging. In particular in Ar/H2O mixtures we could study the evolution from early atomic dissociation in the discharge, to longer time scales, when chemical reactions take place producing an increase of the density of species such as OH, H2O2 and subsequently of H and H2. The results of numerical simulations provide some insights into the evolution happening in the plasma gas-phase during the hydrogen reforming process.

Reinterpreting the best biomarker of oxidative stress: The 8-iso-PGF(2α)/PGF(2α) ratio distinguishes chemical from enzymatic lipid peroxidation.

Science.gov (United States)

van 't Erve, Thomas J; Lih, Fred B; Kadiiska, Maria B; Deterding, Leesa J; Eling, Thomas E; Mason, Ronald P

2015-06-01

The biomarker 8-iso-prostaglandin F2α (8-iso-PGF2α) is regarded as the gold standard for detection of excessive chemical lipid peroxidation in humans. However, biosynthesis of 8-iso-PGF2α via enzymatic lipid peroxidation by prostaglandin-endoperoxide synthases (PGHSs), which are significantly induced in inflammation, could lead to incorrect biomarker interpretation. To resolve the ambiguity with this biomarker, the ratio of 8-iso-PGF2α to prostaglandin F2α (PGF2α) is established as a quantitative measure to distinguish enzymatic from chemical lipid peroxidation in vitro, in animal models, and in humans. Using this method, we find that chemical lipid peroxidation contributes only 3% to the total 8-iso-PGF2α in the plasma of rats. In contrast, the 8-iso-PGF2α levels in plasma of human males are generated >99% by chemical lipid peroxidation. This establishes the potential for an alternate pathway of biomarker synthesis, and draws into question the source of increases in 8-iso-PGF2α seen in many human diseases. In conclusion, increases in 8-iso-PGF2α do not necessarily reflect increases in oxidative stress; therefore, past studies using 8-iso-PGF2α as a marker of oxidative stress may have been misinterpreted. The 8-iso-PGF2α/PGF2α ratio can be used to distinguish biomarker synthesis pathways and thus confirm the potential change in oxidative stress in the myriad of disease and chemical exposures known to induce 8-iso-PGF2α. Published by Elsevier Inc.

Hydrogen peroxide stabilization in one-dimensional flow columns

Science.gov (United States)

Schmidt, Jeremy T.; Ahmad, Mushtaque; Teel, Amy L.; Watts, Richard J.

2011-09-01

Rapid hydrogen peroxide decomposition is the primary limitation of catalyzed H 2O 2 propagations in situ chemical oxidation (CHP ISCO) remediation of the subsurface. Two stabilizers of hydrogen peroxide, citrate and phytate, were investigated for their effectiveness in one-dimensional columns of iron oxide-coated and manganese oxide-coated sand. Hydrogen peroxide (5%) with and without 25 mM citrate or phytate was applied to the columns and samples were collected at 8 ports spaced 13 cm apart. Citrate was not an effective stabilizer for hydrogen peroxide in iron-coated sand; however, phytate was highly effective, increasing hydrogen peroxide residuals two orders of magnitude over unstabilized hydrogen peroxide. Both citrate and phytate were effective stabilizers for manganese-coated sand, increasing hydrogen peroxide residuals by four-fold over unstabilized hydrogen peroxide. Phytate and citrate did not degrade and were not retarded in the sand columns; furthermore, the addition of the stabilizers increased column flow rates relative to unstabilized columns. These results demonstrate that citrate and phytate are effective stabilizers of hydrogen peroxide under the dynamic conditions of one-dimensional columns, and suggest that citrate and phytate can be added to hydrogen peroxide before injection to the subsurface as an effective means for increasing the radius of influence of CHP ISCO.

Changes in plasma membrane structure upon irradiation on thymocytes

International Nuclear Information System (INIS)

Dreval', V.I.

1993-01-01

Thymocytes were irradiated with doses of 4 to 10 4 Gy. The binding of 1-anilinonaphtalene-8-sulphonate and Ca 2+ to plasma membranes; viscosity and lipid peroxidation; Stern-Folmer constant; and the number of Sh-groups of membrane proteins were determined. The structural changes in plasma membranes after irradiation of thymocytes were found to be cooperative

New enhanced sensitivity infrared laser spectroscopy techniques applied to reactive plasmas and trace gas detection

NARCIS (Netherlands)

Welzel, S.

2009-01-01

Infrared laser absorption spectroscopy (IRLAS) employing both tuneable diode and quantum cascade lasers (TDLs, QCLs) has been applied with both high sensitivity and high time resolution to plasma diagnostics and trace gas measurements. TDLAS combined with a conventional White type multiple pass cell

Charging of nanoparticles in stationary plasma in a gas aggregation cluster source

Science.gov (United States)

Blažek, J.; Kousal, J.; Biederman, H.; Kylián, O.; Hanuš, J.; Slavínská, D.

2015-10-01

Clusters that grow into nanoparticles near the magnetron target of the gas aggregation cluster source (GAS) may acquire electric charge by collecting electrons and ions or through other mechanisms like secondary- or photo-electron emissions. The region of the GAS close to magnetron may be considered as stationary plasma. The steady state charge distribution on nanoparticles can be determined by means of three possible models—fluid model, kinetic model and model employing Monte Carlo simulations—of cluster charging. In the paper the mathematical and numerical aspects of these models are analyzed in detail and close links between them are clarified. Among others it is shown that Monte Carlo simulation may be considered as a particular numerical technique of solving kinetic equations. Similarly the equations of the fluid model result, after some approximation, from averaged kinetic equations. A new algorithm solving an in principle unlimited set of kinetic equations is suggested. Its efficiency is verified on physical models based on experimental input data.

Gas Plasma Pre-treatment Increases Antibiotic Sensitivity and Persister Eradication in Methicillin-Resistant Staphylococcus aureus

Science.gov (United States)

Guo, Li; Xu, Ruobing; Zhao, Yiming; Liu, Dingxin; Liu, Zhijie; Wang, Xiaohua; Chen, Hailan; Kong, Michael G.

2018-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of serious nosocomial infections, and recurrent MRSA infections primarily result from the survival of persister cells after antibiotic treatment. Gas plasma, a novel source of ROS (reactive oxygen species) and RNS (reactive nitrogen species) generation, not only inactivates pathogenic microbes but also restore the sensitivity of MRSA to antibiotics. This study further found that sublethal treatment of MRSA with both plasma and plasma-activated saline increased the antibiotic sensitivity and promoted the eradication of persister cells by tetracycline, gentamycin, clindamycin, chloramphenicol, ciprofloxacin, rifampicin, and vancomycin. The short-lived ROS and RNS generated by plasma played a primary role in the process and induced the increase of many species of ROS and RNS in MRSA cells. Thus, our data indicated that the plasma treatment could promote the effects of many different classes of antibiotics and act as an antibiotic sensitizer for the treatment of antibiotic-resistant bacteria involved in infectious diseases. PMID:29628915

Simulation studies of gas and plasma-based charge strippers

Energy Technology Data Exchange (ETDEWEB)

Haas, Oliver Sebastian [Institut fuer Theorie Elektromagnetischer Felder, Technische Univ. Darmstadt (Germany); Boine-Frankenheim, Oliver [Institut fuer Theorie Elektromagnetischer Felder, Technische Univ. Darmstadt (Germany); GSI Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany)

2016-07-01

Charge stripping of heavy ion beams at high intensities is a major challenge in current and future facilities with high intensity heavy ion beams. Conventional stripping techniques are limited in their applicability, e.g. solid carbon foils suffer from short lifetimes at high intensities and gas strippers usually achieve only low charge states. One possible alternative is the use of a plasma as a stripping medium. The presented work focuses on theoretical studies of the interaction of an heavy ion beam with a plasma and accompanying effects in possible charge strippers. The main interest in the presented studies is the final charge state distribution of the ion beam. Different models for solving the corresponding rate equations were developed, taking into account ionization, recombination, energy loss and straggling processes. Sophisticated models, e.g. for ionization cross sections, as well as limits and applicability of simplified models are discussed. Quantitative results are presented in form an overview of the charge state distributions of different - conventional and novel - charge stripping media. Furthermore comparisons are done with charge state distributions of available experimental data. Typical practically relevant target conditions are discussed as well as deterioration of beam quality.

Formation of a Boundary-Free Dust Cluster in a Low-Pressure Gas-Discharge Plasma

International Nuclear Information System (INIS)

Usachev, A. D.; Zobnin, A. V.; Petrov, O. F.; Fortov, V. E.; Annaratone, B. M.; Thoma, M. H.; Hoefner, H.; Kretschmer, M.; Fink, M.; Morfill, G. E.

2009-01-01

An attraction between negatively charged micron-sized plastic particles was observed in the bulk of a low-pressure gas-discharge plasma under microgravity conditions. This attraction had led to the formation of a boundary-free dust cluster, containing one big central particle with a radius of about 6 μm and about 30 1 μm-sized particles situated on a sphere with a radius of 190 μm and with the big particle in the center. The stability of this boundary-free dust cluster was possible due to its confinement by the plasma flux on the central dust particle

Direct analysis of ultra-trace semiconductor gas by inductively coupled plasma mass spectrometry coupled with gas to particle conversion-gas exchange technique.

Science.gov (United States)

Ohata, Masaki; Sakurai, Hiromu; Nishiguchi, Kohei; Utani, Keisuke; Günther, Detlef

2015-09-03

An inductively coupled plasma mass spectrometry (ICPMS) coupled with gas to particle conversion-gas exchange technique was applied to the direct analysis of ultra-trace semiconductor gas in ambient air. The ultra-trace semiconductor gases such as arsine (AsH3) and phosphine (PH3) were converted to particles by reaction with ozone (O3) and ammonia (NH3) gases within a gas to particle conversion device (GPD). The converted particles were directly introduced and measured by ICPMS through a gas exchange device (GED), which could penetrate the particles as well as exchange to Ar from either non-reacted gases such as an air or remaining gases of O3 and NH3. The particle size distribution of converted particles was measured by scanning mobility particle sizer (SMPS) and the results supported the elucidation of particle agglomeration between the particle converted from semiconductor gas and the particle of ammonium nitrate (NH4NO3) which was produced as major particle in GPD. Stable time-resolved signals from AsH3 and PH3 in air were obtained by GPD-GED-ICPMS with continuous gas introduction; however, the slightly larger fluctuation, which could be due to the ionization fluctuation of particles in ICP, was observed compared to that of metal carbonyl gas in Ar introduced directly into ICPMS. The linear regression lines were obtained and the limits of detection (LODs) of 1.5 pL L(-1) and 2.4 nL L(-1) for AsH3 and PH3, respectively, were estimated. Since these LODs revealed sufficiently lower values than the measurement concentrations required from semiconductor industry such as 0.5 nL L(-1) and 30 nL L(-1) for AsH3 and PH3, respectively, the GPD-GED-ICPMS could be useful for direct and high sensitive analysis of ultra-trace semiconductor gas in air. Copyright © 2015 Elsevier B.V. All rights reserved.

Blood compatibility of gas plasma-treated diamond-like carbon surface-Effect of physicochemical properties of DLC surface on blood compatibility

International Nuclear Information System (INIS)

Mochizuki, Akira; Ogawa, Tatsuhisa; Okamoto, Keishi; Nakatani, Tatsuyuki; Nitta, Yuki

2011-01-01

From the knowledge that zwitterion-type polymers show good blood compatibility, the introduction of both cationic and anionic functional groups onto diamond-like carbon (DLC) surface is expected to improve blood compatibility. Thus, DLC films were treated with oxygen and ammonia gas plasmas. The surfaces were characterized in terms of chemical composition by XPS, contact angle, and zeta potential. XPS analysis showed the introductions of a carboxyl group by oxygen plasma treatment and nitrogen atoms by ammonia plasma treatment. The evaluation of blood compatibility for the DLC surfaces was carried out in terms of platelets and the coagulation system. Excellent improvement of platelet compatibility was observed by the treatment with the gas plasmas, regardless of the plasma species. As for the compatibility with the coagulation system, DLC surfaces with a high concentration of carboxyl groups (COOH) markedly activated the system via the intrinsic pathway. However, the surfaces treated with ammonia plasma did not activate the system even though they had high COOH concentration. Measurement of the zeta potential revealed that the ammonia plasma treatment raised the potential from a negative value to a positive one. Though the introduction of amino groups to the surface was not detected directly, the treatment of ammonia plasma changed the electrical state of the DLC surface having COOH group, causing a difference in blood compatibility among the DLCs obtained by various plasma conditions.

Rearrangements of organic peroxides and related processes

Directory of Open Access Journals (Sweden)

Ivan A. Yaremenko

2016-08-01

Full Text Available This review is the first to collate and summarize main data on named and unnamed rearrangement reactions of peroxides. It should be noted, that in the chemistry of peroxides two types of processes are considered under the term rearrangements. These are conventional rearrangements occurring with the retention of the molecular weight and transformations of one of the peroxide moieties after O–O-bond cleavage. Detailed information about the Baeyer−Villiger, Criegee, Hock, Kornblum−DeLaMare, Dakin, Elbs, Schenck, Smith, Wieland, and Story reactions is given. Unnamed rearrangements of organic peroxides and related processes are also analyzed. The rearrangements and related processes of important natural and synthetic peroxides are discussed separately.

Protein oxidation and peroxidation

DEFF Research Database (Denmark)

Davies, Michael Jonathan

2016-01-01

Proteins are major targets for radicals and two-electron oxidants in biological systems due to their abundance and high rate constants for reaction. With highly reactive radicals damage occurs at multiple side-chain and backbone sites. Less reactive species show greater selectivity with regard...... to the residues targeted and their spatial location. Modification can result in increased side-chain hydrophilicity, side-chain and backbone fragmentation, aggregation via covalent cross-linking or hydrophobic interactions, protein unfolding and altered conformation, altered interactions with biological partners...... and modified turnover. In the presence of O2, high yields of peroxyl radicals and peroxides (protein peroxidation) are formed; the latter account for up to 70% of the initial oxidant flux. Protein peroxides can oxidize both proteins and other targets. One-electron reduction results in additional radicals...

Lipid peroxidation in radiation pneumonitis in mouse lung and its preventation

International Nuclear Information System (INIS)

Kodama, Akihisa; Tsujino, Kayoko; Kono, Michio

1998-01-01

Lipid peroxidation of the lung in irradiated C57BL6J mice was analyzed by gas chromatography. Among six major fatty acids in the mouse lung tissue, the amounts of two unsaturated fatty acids, arachidonic acid and DHA reduced one day after irradiation, and then recovered up to the level of in the control group four weeks after irradiation. In contrast, the amounts of stearic and palmitic acid did not change significantly. The mice fed with vitamin E-enriched food showed no significant changes of fatty acids which were compatible with pathophysiological findings 4 weeks after irradiation. Reduction of both arachidonic acid and DHA following lipid peroxidation in lung tissue, was assumed to play an important role in development of radiation pneumonitis. Vitamin E seems to enable to prevent or reduce the occurrence and progression of radiation pneumonitis, but as a radical scavenger, it may also weaken the anti-tumor growth effect of low linear energy transfer (LET) irradiation as photon. (author)

Scaling relations for plasma production and acceleration of rotating plasma flows

International Nuclear Information System (INIS)

Ikehata, Takashi; Tanabe, Toshio; Mase, Hiroshi; Sekine, Ryusuke; Hasegawa, Kazuyuki.

1989-01-01

Scaling relations are investigated theoretically and experimentally of the plasma production and acceleration in the rotating plasma gun which has been developed as a new means of plasma centrifuge. Two operational modes: the gas-discharge mode for gaseous elements and the vacuum-discharge mode for solid elements are studied. Relations of the plasma density and velocities to the discharge current and the magnetic field are derived. The agreement between experiment and theory is quite well. It is found that fully-ionized rotating plasmas produced in the gas-discharge mode is most advantageous to realize efficient plasma centrifuge. (author)

Eriodictyol prevents early retinal and plasma abnormalities in streptozotocin-induced diabetic rats.

Science.gov (United States)

Bucolo, Claudio; Leggio, Gian Marco; Drago, Filippo; Salomone, Salvatore

2012-07-01

Diabetic retinopathy is a complex disease that has potential involvement of inflammatory and oxidative stress-related pathways in its pathogenesis. We hypothesized that eriodictyol, one of the most abundant dietary flavonoids, could be effective against diabetic retinopathy, which involves significant oxidative stress and inflammation. The aim of the present study was to investigate the effects of eriodictyol in early retinal and plasma changes of streptozotocin-induced diabetic rats. The effect of eriodictyol treatment (0.1, 1, 10 mg/kg daily for 10 days) was evaluated by TNF-α, ICAM-1, VEGF, and eNOS protein levels measurement in the retina, plasma lipid peroxidation, and blood-retinal barrier (BRB) integrity. Increased amounts of cytokines, adhesion molecule, and nitric oxide synthase were observed in retina from diabetic rats. Eriodictyol treatment significantly lowered retinal TNF-α, ICAM-1, VEGF, and eNOS in a dose-dependent manner. Further, treatment with eriodictyol significantly suppressed diabetes-related lipid peroxidation, as well as the BRB breakdown. These data demonstrated that eriodictyol attenuates the degree of retinal inflammation and plasma lipid peroxidation preserving the BRB in early diabetic rats. Copyright © 2012 Elsevier Inc. All rights reserved.

Study of soft X-ray energy spectra from gas-puff Z-pinch plasma

International Nuclear Information System (INIS)

Zou Xiaobing; Wang Xinxin; Zhang Guixin; Han Min; Luo Chengmu

2006-01-01

A ROSS-FILTER-PIN spectrometer in the spectral range of 0.28 keV-1.56 keV was developed to study the soft X-ray radiation emitted from gas-puff Z-pinch plasma. It is composed of five channels covering the energy interval of interest without gaps. Soft X-ray spectral energy cuts were determined by the L absorption edges of selected filter elements (K absorption edges being used for light filter elements), and the optimum thickness of filter material was designed using computer code. To minimize the residual sensitivity outside the sensitivity range of each channel, element of the first filter was added into the second filter of all the Ross pair. To diminish the area of each filter, PIN detector with small sensitive area of 1 mm 2 was adopted for the spectrometer. A filter with small area is easy to fabricate and would be helpful to withstand the Z-pinch discharge shock wave. With this ROSS-FILTER-PIN spectrometer, the energy spectra of soft X-ray from a small gas-puff Z-pinch were investigated, and the correlation between the soft X-ray yield and the plasma implosion state was also studied. (authors)

Terahertz Plasma Waves in Two Dimensional Quantum Electron Gas with Electron Scattering

International Nuclear Information System (INIS)

Zhang Liping

2015-01-01

We investigate the Terahertz (THz) plasma waves in a two-dimensional (2D) electron gas in a nanometer field effect transistor (FET) with quantum effects, the electron scattering, the thermal motion of electrons and electron exchange-correlation. We find that, while the electron scattering, the wave number along y direction and the electron exchange-correlation suppress the radiation power, but the thermal motion of electrons and the quantum effects can amplify the radiation power. The radiation frequency decreases with electron exchange-correlation contributions, but increases with quantum effects, the wave number along y direction and thermal motion of electrons. It is worth mentioning that the electron scattering has scarce influence on the radiation frequency. These properties could be of great help to the realization of practical THz plasma oscillations in nanometer FET. (paper)

Plasma Immersion Ion Implantation in Radio Frequency Plasma

International Nuclear Information System (INIS)

Bora, B.; Bhuyan, H.; Wyndham, E.

2013-01-01

Plasma immersion ion implantation (PIII) has attracted wide interests since it emulates conventional ion-beam ion implantation (IBII) in niche applications. For instance, the technique has very high throughput, the implantation time is independent of the sample size, and samples with an irregular shape can be implanted without complex beam scanning or sample manipulation. For uniform ion implantation and deposition on to different substrates, like silicon, stainless steel etc., a capacitive coupled Radio frequency (RF), 13.6 MHz, plasma is used. During the PIII process, the physical parameters which are expected to play crucial rule in the deposition process like RF power, Negative pulse voltage and pulse duration, gas type and gas mixture, gas flow rates and the implantation dose are studied. The ion dose is calculated by dynamic sheath model and the plasma parameters are calculated from the V-I characteristic and power balance equation by homogeneous model of rf plasma discharge considering Ohmic as well as Stochastic heating. The correlations between the yield of the implantation process and the physical parameters as well as plasma parameters are discussed. (author)

Application of lipid peroxidation and protein oxidation biomarkers for oxidative damage in mammalian cells. A comparison with two fluorescent probes

NARCIS (Netherlands)

Orhan, H.; Gurer-Orhan, H.; Vriese, E.; Vermeulen, N.P.E.; Meerman, J.H.N.

2006-01-01

We recently developed two biomarker sets for oxidative damage: one for determination of lipid peroxidation (LPO) degradation products; acetaldehyde, propanal, butanal, pentanal, hexanal, heptanal, octanal, nonanal, malondialdehyde and acetone, by a gas chromatography-electron capture detection

Effect of Mucuna pruriens on semen profile and biochemical parameters in seminal plasma of infertile men.

Science.gov (United States)

Ahmad, Mohammad Kaleem; Mahdi, Abbas Ali; Shukla, Kamla Kant; Islam, Najmul; Jaiswar, Shyam Pyari; Ahmad, Sohail

2008-09-01

To investigate the impact of Mucuna pruriens seeds on semen profiles and biochemical levels in seminal plasma of infertile men. Prospective study. Departments of Biochemistry and Obstetrics and Gynecology, King George's Medical University, Lucknow, India. Sixty normal healthy fertile men (controls) and 60 men undergoing infertility screening. High-performance liquid chromatography assay procedure for quantitation of vitamin A and E in seminal plasma. Biochemical parameters in seminal plasma, namely lipids, fructose, and vitamin C, were estimated by standard spectrophotometric procedures. Before and after the treatment, seminal plasma lipid profile, lipid peroxide, fructose, and antioxidant vitamin levels were measured. Treatment with M. pruriens significantly inhibited lipid peroxidation, elevated spermatogenesis, and improved sperm motility. Treatment also recovered the levels of total lipids, triglycerides, cholesterol, phospholipids, and vitamin A, C, and E and corrected fructose in seminal plasma of infertile men. Treatment with M. pruriens increased sperm concentration and motility in all the infertile study groups. Oligozoospermic patients recovered sperm concentration significantly, but sperm motility was not restored to normal levels in asthenozoospermic men. Furthermore, in the seminal plasma of all the infertile groups, the levels of lipids, antioxidant vitamins, and corrected fructose were recovered after a decrease in lipid peroxides after treatment. The present study is likely to open new vistas on the possible role of M. pruriens seed powder as a restorative and invigorating agent for infertile men.

Spark Plasma Sintering of a Gas Atomized Al7075 Alloy: Microstructure and Properties

Czech Academy of Sciences Publication Activity Database

Molnárová, O.; Málek, P.; Lukáč, František; Chráska, Tomáš

2016-01-01

Roč. 9, č. 12 (2016), č. článku 1004. ISSN 1996-1944 R&D Projects: GA ČR(CZ) GA15-15609S Institutional support: RVO:61389021 Keywords : gas atomized Al7075 alloy * spark plasma sintering * microstructure * microhardness * high temperature stability Subject RIV: JJ - Other Materials Impact factor: 2.654, year: 2016 http://www.mdpi.com/1996-1944/9/12/1004

Deliberation of arc plasma characteristics according to experimental results in a typical gas circuit-breaker

International Nuclear Information System (INIS)

Borghei, M.

2005-01-01

One of the industrial plasma applications is in the gas circuit breakers (GCB) and switching processes. During GCB operation and opening of its two contacts, current flows through of the inter-electrode medium (generally SF 6 or its mixture) and electric arc forms from the plasma that has been created between the contacts. The electric arc is a self-sustained discharge having low voltage drop and able to support great amplitudes of current. The technical basis of circuit breaker is: initiating arc plasma, flowing a large current, cooling it effectively to avoid re-ignition, and finally the transition from a well-conducting medium into insulating gas space in a very short time interval. In other words, for a successful interruption we need to know about power brought to the arc and that of removed. In this paper an attempt has been made to study, characterize and understand some arc behaviors such as arc conductance and its changes according to recorded current and voltage traces experimentally. From physical point of view, there are different phenomena that affect on arc behavior. According to methodology used here, we tried to understand some of arc behavior from experimental results and finally we extract some arc parameters. (author)

Attenuation of acoustic waves through reflections at the plasma neutral gas interfaces: weakly ionised case

International Nuclear Information System (INIS)

Ghosal, S.K.; Sen, S.N.

1977-01-01

The problem of transmission of sonic waves through a weakly ionised plasma bounded in each side by a neutral gas medium has been treated by assuming the plasma to be a mixture of two intermingled fluids viz., neutral particle fluid and ion fluid in equilibrium. From a hydrodynamic analysis the wave equation for 'p', the macroscopic pressure perturbation has been obtained and it is shown that two independent wave motions, one due to the neutral particles and the other due to ions are propagated through the plasma with two different phase velocities. Assuming the usual boundary conditions at the interface, the amplitude of the transmitted wave has been calculated in case of weakly ionized plasma; the theory can be utilized for the determination of electron temperature from the measured value of attenuation if the percentage of ionization and collision cross section can be obtained independently. (author)

High-frequency underwater plasma discharge application in antibacterial activity

Energy Technology Data Exchange (ETDEWEB)

Ahmed, M. W.; Choi, S.; Lyakhov, K.; Shaislamov, U. [Jeju National University, Department of Nuclear and Energy Engineering (Korea, Republic of); Mongre, R. K.; Jeong, D. K. [Jeju National University, Faculty of Biotechnology (Korea, Republic of); Suresh, R.; Lee, H. J., E-mail: hjlee@jejunu.ac.kr [Jeju National University, Department of Nuclear and Energy Engineering (Korea, Republic of)

2017-03-15

Plasma discharge is a novel disinfection and effectual inactivation approach to treat microorganisms in aqueous systems. Inactivation of Gram-negative Escherichia coli (E. coli) by generating high-frequency, high-voltage, oxygen (O{sub 2}) injected and hydrogen peroxide (H{sub 2}O{sub 2}) added discharge in water was achieved. The effect of H{sub 2}O{sub 2} dose and oxygen injection rate on electrical characteristics of discharge and E. coli disinfection has been reported. Microbial log reduction dependent on H{sub 2}O{sub 2} addition with O{sub 2} injection was observed. The time variation of the inactivation efficiency quantified by the log reduction of the initial E. coli population on the basis of optical density measurement was reported. The analysis of emission spectrum recorded after discharge occurrence illustrated the formation of oxidant species (OH{sup •}, H, and O). Interestingly, the results demonstrated that O{sub 2} injected and H{sub 2}O{sub 2} added, underwater plasma discharge had fabulous impact on the E. coli sterilization. The oxygen injection notably reduced the voltage needed for generating breakdown in flowing water and escalated the power of discharge pulses. No impact of hydrogen peroxide addition on breakdown voltage was observed. A significant role of oxidant species in bacterial inactivation also has been identified. Furthermore the E. coli survivability in plasma treated water with oxygen injection and hydrogen peroxide addition drastically reduced to zero. The time course study also showed that the retardant effect on E. coli colony multiplication in plasma treated water was favorable, observed after long time. High-frequency underwater plasma discharge based biological applications is technically relevant and would act as baseline data for the development of novel antibacterial processing strategies.

Kinetics of Platinum-Catalyzed Decomposition of Hydrogen Peroxide

Science.gov (United States)

Vetter, Tiffany A.; Colombo, D. Philip, Jr.

2003-07-01

CIBA Vision Corporation markets a contact lens cleaning system that consists of an AOSEPT disinfectant solution and an AOSEPT lens cup. The disinfectant is a buffered 3.0% m/v hydrogen peroxide solution and the cup includes a platinum-coated AOSEPT disc. The hydrogen peroxide disinfects by killing bacteria, fungi, and viruses found on the contact lenses. Because the concentration of hydrogen peroxide needed to disinfect is irritating to eyes, the hydrogen peroxide needs to be neutralized, or decomposed, before the contact lenses can be used again. A general chemistry experiment is described where the kinetics of the catalyzed decomposition of the hydrogen peroxide are studied by measuring the amount of oxygen generated as a function of time. The order of the reaction with respect to the hydrogen peroxide, the rate constant, and the energy of activation are determined. The integrated rate law is used to determine the time required to decompose the hydrogen peroxide to a concentration that is safe for eyes.

Effect of N{sub 2} and Ar gas on DC arc plasma generation and film composition from Ti-Al compound cathodes

Energy Technology Data Exchange (ETDEWEB)

Zhirkov, Igor, E-mail: igozh@ifm.liu.se; Rosen, Johanna [Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping (Sweden); Oks, Efim [Institute of High Current Electronics SB RAS, 2/3 Akademichesky Avenue, 634055 Tomsk (Russian Federation)

2015-06-07

DC arc plasma from Ti, Al, and Ti{sub 1−x}Al{sub x} (x = 0.16, 0.25, 0.50, and 0.70) compound cathodes has been characterized with respect to plasma chemistry (charged particles) and charge-state-resolved ion energy for Ar and N{sub 2} pressures in the range 10{sup −6} to 3 × 10{sup −2} Torr. Scanning electron microscopy was used for exploring the correlation between the cathode and film composition, which in turn was correlated with the plasma properties. In an Ar atmosphere, the plasma ion composition showed a reduction of Al of approximately 5 at. % compared to the cathode composition, while deposited films were in accordance with the cathode stoichiometry. Introducing N{sub 2} above ∼5 × 10{sup −3} Torr, lead to a reduced Al content in the plasma as well as in the film, and hence a 1:1 correlation between the cathode and film composition cannot be expected in a reactive environment. This may be explained by an influence of the reactive gas on the arc mode and type of erosion of Ti and Al rich contaminations, as well as on the plasma transport. Throughout the investigated pressure range, a higher deposition rate was obtained from cathodes with higher Al content. The origin of generated gas ions was investigated through the velocity rule, stating that the most likely ion velocities of all cathode elements from a compound cathode are equal. The results suggest that the major part of the gas ions in Ar is generated from electron impact ionization, while gas ions in a N{sub 2} atmosphere primarily originate from a nitrogen contaminated layer on the cathode surface. The presented results provide a contribution to the understanding processes of plasma generation from compound cathodes. It also allows for a more reasonable approach to the selection of composite cathode and experimental conditions for thin film depositions.

Enhancement of high-order harmonics in a plasma waveguide formed in clustered Ar gas.

Science.gov (United States)

Geng, Xiaotao; Zhong, Shiyang; Chen, Guanglong; Ling, Weijun; He, Xinkui; Wei, Zhiyi; Kim, Dong Eon

2018-02-05

Generation of high-order harmonics (HHs) is intensified by using a plasma waveguide created by a laser in a clustered gas jet. The formation of a plasma waveguide and the guiding of a laser beam are also demonstrated. Compared to the case without a waveguide, harmonics were strengthened up to nine times, and blue-shifted. Numerical simulation by solving the time-dependent Schrödinger equation in strong field approximation agreed well with experimental results. This result reveals that the strengthening is the result of improved phase matching and that the blue shift is a result of change in fundamental laser frequency due to self-phase modulation (SPM).

Hydrogen Peroxide Probes Directed to Different Cellular Compartments

Science.gov (United States)

Malinouski, Mikalai; Zhou, You; Belousov, Vsevolod V.; Hatfield, Dolph L.; Gladyshev, Vadim N.

2011-01-01

Background Controlled generation and removal of hydrogen peroxide play important roles in cellular redox homeostasis and signaling. We used a hydrogen peroxide biosensor HyPer, targeted to different compartments, to examine these processes in mammalian cells. Principal Findings Reversible responses were observed to various redox perturbations and signaling events. HyPer expressed in HEK 293 cells was found to sense low micromolar levels of hydrogen peroxide. When targeted to various cellular compartments, HyPer occurred in the reduced state in the nucleus, cytosol, peroxisomes, mitochondrial intermembrane space and mitochondrial matrix, but low levels of the oxidized form of the biosensor were also observed in each of these compartments, consistent with a low peroxide tone in mammalian cells. In contrast, HyPer was mostly oxidized in the endoplasmic reticulum. Using this system, we characterized control of hydrogen peroxide in various cell systems, such as cells deficient in thioredoxin reductase, sulfhydryl oxidases or subjected to selenium deficiency. Generation of hydrogen peroxide could also be monitored in various compartments following signaling events. Conclusions We found that HyPer can be used as a valuable tool to monitor hydrogen peroxide generated in different cellular compartments. The data also show that hydrogen peroxide generated in one compartment could translocate to other compartments. Our data provide information on compartmentalization, dynamics and homeostatic control of hydrogen peroxide in mammalian cells. PMID:21283738

Hydrogen peroxide probes directed to different cellular compartments.

Directory of Open Access Journals (Sweden)

Mikalai Malinouski

2011-01-01

Full Text Available Controlled generation and removal of hydrogen peroxide play important roles in cellular redox homeostasis and signaling. We used a hydrogen peroxide biosensor HyPer, targeted to different compartments, to examine these processes in mammalian cells.Reversible responses were observed to various redox perturbations and signaling events. HyPer expressed in HEK 293 cells was found to sense low micromolar levels of hydrogen peroxide. When targeted to various cellular compartments, HyPer occurred in the reduced state in the nucleus, cytosol, peroxisomes, mitochondrial intermembrane space and mitochondrial matrix, but low levels of the oxidized form of the biosensor were also observed in each of these compartments, consistent with a low peroxide tone in mammalian cells. In contrast, HyPer was mostly oxidized in the endoplasmic reticulum. Using this system, we characterized control of hydrogen peroxide in various cell systems, such as cells deficient in thioredoxin reductase, sulfhydryl oxidases or subjected to selenium deficiency. Generation of hydrogen peroxide could also be monitored in various compartments following signaling events.We found that HyPer can be used as a valuable tool to monitor hydrogen peroxide generated in different cellular compartments. The data also show that hydrogen peroxide generated in one compartment could translocate to other compartments. Our data provide information on compartmentalization, dynamics and homeostatic control of hydrogen peroxide in mammalian cells.

High power light gas helicon plasma source for VASIMR

International Nuclear Information System (INIS)

Squire, Jared P.; Chang-Diaz, Franklin R.; Glover, Timothy W.; Jacobson, Verlin T.; McCaskill, Greg E.; Winter, D. Scott; Baity, F. Wally; Carter, Mark D.; Goulding, Richard H.

2006-01-01

In the Advanced Space Propulsion Laboratory (ASPL) helicon experiment (VX-10) we have measured a plasma flux to input gas rate ratio near 100% for both helium and deuterium at power levels up to 10 kW. Recent results at Oak Ridge National Laboratory (ORNL) show enhanced efficiency operation with a high power density, over 5 kW in a 5 cm diameter tube. Our helicon is presently 9 cm in diameter and operates up to 10 kW of input power. The data here uses a Boswell double-saddle antenna design with a magnetic cusp just upstream of the antenna. Similar to ORNL, for deuterium at near 10 kW, we find an enhanced performance of operation at magnetic fields above the lower hybrid matching condition

Charge dependence of the plasma travel length in atmospheric-pressure plasma

Energy Technology Data Exchange (ETDEWEB)

Yambe, Kiyoyuki; Konda, Kohmei; Masuda, Seiya [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan)

2016-06-15

Plasma plume is generated using a quartz tube, helium gas, and foil electrode by applying AC high voltage under the atmosphere. The plasma plume is released into the atmosphere from inside of the quartz tube and is seen as the continuous movement of the plasma bullet. The travel length of plasma bullet is defined from plasma energy and force due to electric field. The drift velocity of plasma bullet has the upper limit under atmospheric-pressure because the drift velocity is determined from the balance between electric field and resistive force due to collisions between plasma and air. The plasma plume charge depends on the drift velocity. Consequently, in the laminar flow of helium gas flow state, the travel length of the plasma plume logarithmically depends on the plasma plume charge which changes with both the electric field and the resistive force.

Charge dependence of the plasma travel length in atmospheric-pressure plasma

International Nuclear Information System (INIS)

Yambe, Kiyoyuki; Konda, Kohmei; Masuda, Seiya

2016-01-01

Plasma plume is generated using a quartz tube, helium gas, and foil electrode by applying AC high voltage under the atmosphere. The plasma plume is released into the atmosphere from inside of the quartz tube and is seen as the continuous movement of the plasma bullet. The travel length of plasma bullet is defined from plasma energy and force due to electric field. The drift velocity of plasma bullet has the upper limit under atmospheric-pressure because the drift velocity is determined from the balance between electric field and resistive force due to collisions between plasma and air. The plasma plume charge depends on the drift velocity. Consequently, in the laminar flow of helium gas flow state, the travel length of the plasma plume logarithmically depends on the plasma plume charge which changes with both the electric field and the resistive force.

Intracellular ROS mediates gas plasma-facilitated cellular transfection in 2D and 3D cultures

Science.gov (United States)

Xu, Dehui; Wang, Biqing; Xu, Yujing; Chen, Zeyu; Cui, Qinjie; Yang, Yanjie; Chen, Hailan; Kong, Michael G.

2016-01-01

This study reports the potential of cold atmospheric plasma (CAP) as a versatile tool for delivering oligonucleotides into mammalian cells. Compared to lipofection and electroporation methods, plasma transfection showed a better uptake efficiency and less cell death in the transfection of oligonucleotides. We demonstrated that the level of extracellular aqueous reactive oxygen species (ROS) produced by gas plasma is correlated with the uptake efficiency and that this is achieved through an increase of intracellular ROS levels and the resulting increase in cell membrane permeability. This finding was supported by the use of ROS scavengers, which reduced CAP-based uptake efficiency. In addition, we found that cold atmospheric plasma could transfer oligonucleotides such as siRNA and miRNA into cells even in 3D cultures, thus suggesting the potential for unique applications of CAP beyond those provided by standard transfection techniques. Together, our results suggest that cold plasma might provide an efficient technique for the delivery of siRNA and miRNA in 2D and 3D culture models. PMID:27296089

Effects of Cr methionine on glucose metabolism, plasma metabolites, meat lipid peroxidation, and tissue chromium in Mahabadi goat kids.

Science.gov (United States)

Emami, A; Ganjkhanlou, M; Zali, A

2015-03-01

This study was designed to investigate the effects of chromium methionine (Cr-Met) on glucose metabolism, blood metabolites, meat lipid peroxidation, and tissue chromium (Cr) in Mahabadi goat kids. Thirty-two male kids (16.5 ± 2.8 kg BW, 4-5 months of age) were fed for 90 days in a completely randomized design with four treatments. Treatments were supplemented with 0 (control), 0.5, 1, and 1.5 mg Cr as Cr-Met/animal/daily. Blood samples were collected via heparin tubes from the jugular vein on 0, 21, 42, 63, and 90 days of experiment. On day 70, an intravenous glucose tolerance test (IVGTT) was conducted. At the end of the feeding trial, the kids were slaughtered, and the liver, kidney, and longissimus dorsi (LD) muscle samples were collected. Plasma glucose, insulin, and triglyceride concentrations were decreased by Cr supplementation (P glucose concentrations at 30 and 60 min after glucose infusion were lower in the kids fed 1.5 mg Cr diet than the kids fed control diet (P glucose clearance rate (K) and lower glucose half-life (T½; P Glucose area under the response curve (AUC) from 0 to 180 min after glucose infusion was decreased linearly (P glucose utilization and lipid oxidation of meat in fattening kid.

Physics of plasma etching and plasma deposition

NARCIS (Netherlands)

Schram, D.C.; Hoog, de F.J.; Bisschops, T.J.; Kroesen, G.M.W.; Howorka, F.; Lindinger, W.; Maerk, T.D.

1986-01-01

The kinetics and mechanism of the title processes are discussed on the basis of a model in which the plasma-surface system is subdivided into 5 regions: (I) plasma prodn., (II) plasma flow plus radicals, (III) gas adsorbed layer, (IV) modified surface, and (V) undisturbed solid (or liq.) state.

Hydrogen peroxide treatment of TCE contaminated soil

International Nuclear Information System (INIS)

Hurst, D.H.; Robinson, K.G.; Siegrist, R.L.

1993-01-01

Solvent contaminated soils are ubiquitous in the industrial world and represent a significant environmental hazard due to their persistence and potentially negative impacts on human health and the environment. Environmental regulations favor treatment of soils with options which reduce the volume and toxicity of contaminants in place. One such treatment option is the in-situ application of hydrogen peroxide to soils contaminated with chlorinated solvents such as trichloroethylene (TCE). This study investigated hydrogen peroxide mass loading rates on removal of TCE from soils of varying organic matter content. Batch experiments conducted on contaminated loam samples using GC headspace analysis showed up to 80% TCE removal upon peroxide treatment. Column experiments conducted on sandy loam soils with high organic matter content showed only 25% TCE removal, even at hydrogen peroxide additions of 25 g peroxide per kg soil

Synthesis of aluminum nitride films by plasma immersion ion implantation-deposition using hybrid gas-metal cathodic arc gun

International Nuclear Information System (INIS)

Shen Liru; Fu, Ricky K.Y.; Chu, Paul K.

2004-01-01

Aluminum nitride (AlN) is of interest in the industry because of its excellent electronic, optical, acoustic, thermal, and mechanical properties. In this work, aluminum nitride films are deposited on silicon wafers (100) by metal plasma immersion ion implantation and deposition (PIIID) using a modified hybrid gas-metal cathodic arc plasma source and with no intentional heating to the substrate. The mixed metal and gaseous plasma is generated by feeding the gas into the arc discharge region. The deposition rate is found to mainly depend on the Al ion flux from the cathodic arc source and is only slightly affected by the N 2 flow rate. The AlN films fabricated by this method exhibit a cubic crystalline microstructure with stable and low internal stress. The surface of the AlN films is quite smooth with the surface roughness on the order of 1/2 nm as determined by atomic force microscopy, homogeneous, and continuous, and the dense granular microstructures give rise to good adhesion with the substrate. The N to Al ratio increases with the bias voltage applied to the substrates. A fairly large amount of O originating from the residual vacuum is found in the samples with low N:Al ratios, but a high bias reduces the oxygen concentration. The compositions, microstructures and crystal states of the deposited films are quite stable and remain unchanged after annealing at 800 deg. C for 1 h. Our hybrid gas-metal source cathodic arc source delivers better AlN thin films than conventional PIIID employing dual plasmas

Dust cloud evolution in sub-stellar atmospheres via plasma deposition and plasma sputtering

Science.gov (United States)

Stark, C. R.; Diver, D. A.

2018-04-01

Context. In contemporary sub-stellar model atmospheres, dust growth occurs through neutral gas-phase surface chemistry. Recently, there has been a growing body of theoretical and observational evidence suggesting that ionisation processes can also occur. As a result, atmospheres are populated by regions composed of plasma, gas and dust, and the consequent influence of plasma processes on dust evolution is enhanced. Aim. This paper aims to introduce a new model of dust growth and destruction in sub-stellar atmospheres via plasma deposition and plasma sputtering. Methods: Using example sub-stellar atmospheres from DRIFT-PHOENIX, we have compared plasma deposition and sputtering timescales to those from neutral gas-phase surface chemistry to ascertain their regimes of influence. We calculated the plasma sputtering yield and discuss the circumstances where plasma sputtering dominates over deposition. Results: Within the highest dust density cloud regions, plasma deposition and sputtering dominates over neutral gas-phase surface chemistry if the degree of ionisation is ≳10-4. Loosely bound grains with surface binding energies of the order of 0.1-1 eV are susceptible to destruction through plasma sputtering for feasible degrees of ionisation and electron temperatures; whereas, strong crystalline grains with binding energies of the order 10 eV are resistant to sputtering. Conclusions: The mathematical framework outlined sets the foundation for the inclusion of plasma deposition and plasma sputtering in global dust cloud formation models of sub-stellar atmospheres.

Production of simplex RNS and ROS by nanosecond pulse N2/O2 plasma jets with homogeneous shielding gas for inducing myeloma cell apoptosis

Science.gov (United States)

Liu, Zhijie; Xu, Dehui; Liu, Dingxin; Cui, Qingjie; Cai, Haifeng; Li, Qiaosong; Chen, Hailan; Kong, Michael G.

2017-05-01

In this paper, atmospheric pressure N2/O2 plasma jets with homogeneous shielding gas excited by nanosecond pulse are obtained to generate simplex reactive nitrogen species (RNS) and reactive oxygen species (ROS), respectively, for the purpose of studying the simplex RNS and ROS to induce the myeloma cell apoptosis with the same discharge power. The results reveal that the cell death rate by the N2 plasma jet with N2 shielding gas is about two times that of the O2 plasma jet with O2 shielding gas for the equivalent treatment time. By diagnosing the reactive species of ONOO-, H2O2, OH and \\text{O}2- in medium, our findings suggest the cell death rate after plasma jets treatment has a positive correlation with the concentration of ONOO-. Therefore, the ONOO- in medium is thought to play an important role in the process of inducing myeloma cell apoptosis.

Fabrication and testing of gas filled targets for large scale plasma experiments on Nova

International Nuclear Information System (INIS)

Stone, G.F.; Spragge, M.; Wallace, R.J.; Rivers, C.J.

1995-01-01

An experimental campaign on the Nova laser was started in July 1993 to study one st of target conditions for the point design of the National Ignition Facility (NIF). The targets were specified to investigate the current NIF target conditions--a plasma of ∼3 keV electron temperature and an electron density of ∼1.0 E + 21 cm -3 . A gas cell target design was chosen to confine as gas of ∼0.01 cm 3 in volume at ∼ 1 atmosphere. This paper will describe the major steps and processes necessary in the fabrication, testing and delivery of these targets for shots on the Nova Laser at LLNL

Plasma centrifuge

International Nuclear Information System (INIS)

Ikehata, Takashi; Mase, Hiroshi

1998-01-01

The plasma centrifuge is one of statistical isotope separation processes which uses the centrifugal force of a J x B driven rotating plasma in a magnetic field to give rise to the mass-dependent radial transport of isotopic ions. The system has been developed as an alternative to the gas centrifuge because a much higher rotational velocity and separation factor have been achieved. In this review, the physical aspects of the plasma centrifuge followed by the recent experimental achievements are described, especially in comparison with the gas centrifuge. (author)

Effect of solution plasma process with bubbling gas on physicochemical properties of chitosan.

Science.gov (United States)

Ma, Fengming; Li, Pu; Zhang, Baiqing; Zhao, Xin; Fu, Qun; Wang, Zhenyu; Gu, Cailian

2017-05-01

In the present work, solution plasma process (SPP) with bubbling gas was used to prepare oligochitosan. The effect of SPP irradiation with bubbling gas on the degradation of chitosan was evaluated by the intrinsic viscosity reduction rate and the degradation kinetic. The formation of OH radical was studied. Changes of the physicochemical properties of chitosan were measured by scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis, as well as ultraviolet-visible, Fourier-transform infrared, and 13 C nuclear magnetic resonance spectroscopy. The results indicated an obvious decrease in the intrinsic viscosity reduction rate after SPP irradiation with bubbling gas, and that the rate with bubbling was higher than that without. The main chemical structure of chitosan remained intact after irradiation, but changes in the morphology, crystallinity, and thermal stability of oligochitosan were observed. In particular, the crystallinity and thermal stability tended to decrease. The present study indicated that SPP can be effectively used for the degradation of chitosan. Copyright © 2017. Published by Elsevier B.V.

Removal of formaldehyde from gas streams via packed-bed dielectric barrier discharge plasmas

International Nuclear Information System (INIS)

Ding Huixian; Zhu Aimin; Yang Xuefeng; Li Cuihong; Xu Yong

2005-01-01

Formaldehyde is a major indoor air pollutant and can cause serious health disorders in residents. This work reports the removal of formaldehyde from gas streams via alumina-pellet-filled dielectric barrier discharge plasmas at atmospheric pressure and 70 deg. C. With a feed gas mixture of 140 ppm HCHO, 21.0% O 2 , 1.0% H 2 O in N 2 , ∼92% of formaldehyde can be effectively destructed at GHSV (gas flow volume per hour per discharge volume) of 16 500 h -1 and E in = 108 J l -1 . An increase in the specific surface area of the alumina pellets enhances the HCHO removal, and this indicates that the adsorbed HCHO species may have a lower C-H bond breakage energy. Based on an examination of the influence of gas composition on the removal efficiency, the primary destruction pathways, besides the reactions initiated by discharge-generated radicals, such as O, H, OH and HO 2 , may include the consecutive dissociations of HCHO molecules and HCO radicals through their collisions with vibrationally- and electronically-excited metastable N 2 species. The increase of O 2 content in the inlet gas stream is able to diminish the CO production and to promote the formation of CO 2 via O-atom or HO 2 -radical involved reactions

Gas fueling system for SST-1

International Nuclear Information System (INIS)

Dhanani, Kalpeshkumar R.; Khan, Ziauddin; Raval, Dilip; Semwal, Pratibha; George, Siju; Paravastu, Yuvakiran; Thankey, Prashant; Khan, Mohammad Shoaib; Pradhan, Subrata

2015-01-01

SST-1 Tokamak, the first Indian Steady-state Superconducting experimental device is at present under operation in Institute for Plasma Research. For plasma break down and initiation, the piezoelectric valve based gas feed system is implemented as primary requirement due to its precise control, easy handling, low costs for both construction and maintenance and its flexibility in working gas selection. The main functions of SST-1 gas feed system are to feed the required amount of ultrahigh purity hydrogen gas for specified period into the vessel during plasma operation and ultrahigh helium gas for glow discharge cleaning. In addition to these facilities, the gas feed system is used to feed a mixture gas of hydrogen and helium as well as other gases like nitrogen and Argon during divertor cooling etc. The piezoelectric valves used in SST-1 are remotely driven by a PXI based platform and are calibrated before the plasma operation during each SST-1 plasma operation with precise control. This paper will present the technical development and the results of gas fueling in SST-1. (author)

2XIIB plasma confinement experiments

International Nuclear Information System (INIS)

Coensgen, F.H.; Clauser, J.F.; Correll, D.L.

1976-01-01

This paper reports results of 2XIIB neutral-beam injection experiments with plasma-stream stabilization. The plasma stream is provided either by a pulsed plasma generator located on the field lines outside the plasma region or by ionization of neutral gas introduced at the mirror throat. In the latter case, the gas is ionized by the normal particle flux through the magnetic mirror. A method of plasma startup and sustenance in a steady-state magnetic field is reported in which the plasma stream from the pulsed plasma generator serves as the initial target for the neutral beams. After an energetic plasma of sufficient density is established, the plasma generator stream is replaced by the gas-fed stream. Lifetimes of the stabilized plasma increase with plasma temperature in agreement with the plasma stabilization of the drift-cyclotron loss-cone mode. The following plasma parameters are attained using the pulsed plasma generator for stabilization: n approximately 5 x 10 13 cm -3 , anti W/sub i/ approximately 13 keV, T/sub e/ = 140 eV, and ntau/sub p/ approximately 7 x 10 10 cm -3 .s. With the gas feed, the mean deuterium ion energy is 9 keV and the peak density n approximately 10 14 cm -3 . In the latter case, the energy confinement parameter reaches ntau/sub E/ = 7 x 10 10 cm -3 .s, and the particle confinement parameter reaches ntau/sub p/ = 1 x 10 11 cm -3 .s

[Determination of endogenous agmatine in rat plasma by isotope dilution-gas chromatography-mass spectrometry].

Science.gov (United States)

Qiu, Zhongli; Lin, Ying; Xiong, Zhili; Xie, Jianwei

2014-07-01

A method for the determination of endogenous agmatine in rat plasma was developed by isotope dilution-gas chromatography-negative chemical ionization mass spectrometry (GC-NCI/MS). The plasma samples were analyzed after protein precipitation, evaporation, derivatization by hexafluoroacetone (HFAA), and clean-up on a Florisil SPE column. The GC-MS analysis utilized stable isotope d8-agmatine as internal standard. The samples after treatme were tested by negative chemical ionization with selected ion monitoring (SIM) which was set at m/z 492 (molecular ion of agmatine) and m/z 500 (molecular ion of internal standard). The limit of detection (LOD) of agmatine standard solution was 0.005 7 ng/mL. The calibration curve of the agmatine spiked in rat plasma showed a good linear relationship at the range of 1.14-57.0 ng/mL (r = 0.997). The recoveries of agmatine spiked in rat plasma ranged from 92.3% to 109.8%. Inter-day and intra-day precisions were less than 15%. The average concentration level of agmatine in rat plasma was (22 +/- 9) ng/mL, and there was no significant difference between male and female SD rats (p > 0.05). The method is high sensitive and specific, and can be used for the determination of endogenous agmatine in plasma. It provides a strong support for the subsequent research of agmatine.

Effect of antioxidants and silicates on peroxides in povidone.

Science.gov (United States)

Narang, Ajit S; Rao, Venkatramana M; Desai, Divyakant S

2012-01-01

Reactive peroxides in povidone often lead to degradation of oxidation-labile drugs. To reduce peroxide concentration in povidone, the roles of storage conditions, antioxidants, and silicates were investigated. Povidone alone and its physical mixtures with ascorbic acid, propyl gallate, sodium sulfite, butylated hydroxyanisole (BHA), or butylated hydroxytoluene (BHT) were stored at 25 °C and 40 °C, at 11%, 32%, and 50% relative humidity. In addition, povidone solution in methanol was equilibrated with silicates (silica gel and molecular sieves), followed by solvent evaporation to recover povidone powder. Peroxide concentrations in povidone were measured. The concentration of peroxides in povidone increased under very-low-humidity storage conditions. Among the antioxidants, ascorbic acid, propyl gallate, and sodium sulfite reduced the peroxide concentration in povidone, whereas BHA and BHT did not. Water solubility appeared to determine the effectiveness of antioxidants. Also, some silicates significantly reduced peroxide concentration in povidone without affecting its functionality as a tablet binder. Porosity of silicates was critical to their ability to reduce the peroxide concentration in povidone. A combination of these approaches can reduce the initial peroxide concentration in povidone and minimize peroxide growth under routine storage conditions. Copyright © 2011 Wiley-Liss, Inc.

Determination of hydrogen peroxide in water by chemiluminescence detection, (1). Flow injection type hydrogen peroxide detection system

International Nuclear Information System (INIS)

Yamashiro, Naoya; Uchida, Shunsuke; Satoh, Yoshiyuki; Morishima, Yusuke; Yokoyama, Hiroaki; Satoh, Tomonori; Sugama, Junichi; Yamada, Rie

2004-01-01

A flow injection type hydrogen peroxide detection system with a sub-ppb detection limit has been developed to determine hydrogen peroxide concentration in water sampled from a high temperature, high pressure hydrogen peroxide water loop. The hydrogen peroxide detector is based on luminol chemiluminescence spectroscopy. A small amount of sample water (20 μl) is mixed with a reagent mixture, an aqueous solution of luminol and Co 2+ catalyst, in a mixing cell which is installed just upstream from the detection cell. The optimum values for pH and the concentrations of luminol and Co 2+ ion have been determined to ensure a lower detectable limit and a higher reproducibility. The photocurrent detected by the detection system is expressed by a linear function of the hydrogen peroxide concentration in the region of lower concentration ([H 2 O 2 ] 2 O 2 ] in the region of higher concentration ([H 2 O 2 ] > 10 ppb). The luminous intensity of luminol chemiluminescence is the highest when pH of the reagent mixture is 11.0. Optimization of the major parameters gives the lowest detectable limit of 0.3 ppb. (author)

The influence of gas pressure on E↔H mode transition in argon inductively coupled plasmas

Science.gov (United States)

Zhang, Xiao; Zhang, Zhong-kai; Cao, Jin-xiang; Liu, Yu; Yu, Peng-cheng

2018-03-01

Considering the gas pressure and radio frequency power change, the mode transition of E↔H were investigated in inductively coupled plasmas. It can be found that the transition power has almost the same trend decreasing with gas pressure, whether it is in H mode or E mode. However, the transition density increases slowly with gas pressure from E to H mode. The transition points of E to H mode can be understood by the propagation of electromagnetic wave in the plasma, while the H to E should be illustrated by the electric field strength. Moreover, the electron density, increasing with the pressure and power, can be attributed to the multiple ionization, which changes the energy loss per electron-ion pair created. In addition, the optical emission characteristics in E and H mode is also shown. The line ratio of I750.4 and I811.5, taken as a proxy of the density of metastable state atoms, was used to illustrate the hysteresis. The 750.4 nm line intensity, which has almost the same trend with the 811.5 nm line intensity in H mode, both of them increases with power but decreases with gas pressure. The line ratio of 811.5/750.4 has a different change rule in E mode and H mode, and at the transition point of H to E, it can be one significant factor that results in the hysteresis as the gas pressure change. And compared with the 811.5 nm intensity, it seems like a similar change rule with RF power in E mode. Moreover, some emitted lines with lower rate constants don't turn up in E mode, while can be seen in H mode because the excited state atom density increasing with the electron density.

Special issue: Plasma Conversion

NARCIS (Netherlands)

Nozaki, T.; Bogaerts, A.; Tu, X.; van de Sanden, M. C. M.

2017-01-01

With growing concern of energy and environmental issues, the combination of plasma and heterogeneous catalysts receives special attention in greenhouse gas conversion, nitrogen fixation and hydrocarbon chemistry. Plasma gas conversion driven by renewable electricity is particularly important for the

Electron temperature and density measurement of tungsten inert gas arcs with Ar-He shielding gas mixture

Science.gov (United States)

Kühn-Kauffeldt, M.; Marques, J.-L.; Forster, G.; Schein, J.

2013-10-01

The diagnostics of atmospheric welding plasma is a well-established technology. In most cases the measurements are limited to processes using pure shielding gas. However in many applications shielding gas is a mixture of various components including metal vapor in gas metal arc welding (GMAW). Shielding gas mixtures are intentionally used for tungsten inert gas (TIG) welding in order to improve the welding performance. For example adding Helium to Argon shielding gas allows the weld geometry and porosity to be influenced. Yet thermal plasmas produced with gas mixtures or metal vapor still require further experimental investigation. In this work coherent Thomson scattering is used to measure electron temperature and density in these plasmas, since this technique allows independent measurements of electron and ion temperature. Here thermal plasmas generated by a TIG process with 50% Argon and 50% Helium shielding gas mixture have been investigated. Electron temperature and density measured by coherent Thomson scattering have been compared to the results of spectroscopic measurements of the plasma density using Stark broadening of the 696.5 nm Argon spectral line. Further investigations of MIG processes using Thomson scattering technique are planned.

Electron temperature and density measurement of tungsten inert gas arcs with Ar-He shielding gas mixture

International Nuclear Information System (INIS)

Kühn-Kauffeldt, M; Marques, J-L; Forster, G; Schein, J

2013-01-01

The diagnostics of atmospheric welding plasma is a well-established technology. In most cases the measurements are limited to processes using pure shielding gas. However in many applications shielding gas is a mixture of various components including metal vapor in gas metal arc welding (GMAW). Shielding gas mixtures are intentionally used for tungsten inert gas (TIG) welding in order to improve the welding performance. For example adding Helium to Argon shielding gas allows the weld geometry and porosity to be influenced. Yet thermal plasmas produced with gas mixtures or metal vapor still require further experimental investigation. In this work coherent Thomson scattering is used to measure electron temperature and density in these plasmas, since this technique allows independent measurements of electron and ion temperature. Here thermal plasmas generated by a TIG process with 50% Argon and 50% Helium shielding gas mixture have been investigated. Electron temperature and density measured by coherent Thomson scattering have been compared to the results of spectroscopic measurements of the plasma density using Stark broadening of the 696.5 nm Argon spectral line. Further investigations of MIG processes using Thomson scattering technique are planned

Generation of volatile hydrocarbons as a measure of radiation-induced lipid peroxidation in vitro

Energy Technology Data Exchange (ETDEWEB)

Dobbs, C R; Kumar, K S; Weiss, J F; Catravas, G N [Armed Forces Radiobiology Research Inst., Bethesda, MD (USA)

1981-04-01

Using gas chromatography techniques, pentane production from microsomes could be detected at gamma radiation doses as low as 50 Gy, but definite increases were observed only with the addition of the peroxidation promoter ADP-Fe. There was a small but linear increase in pentane production, and presumably lipid peroxidation, when nonirradiated microsomes alone were incubated. The addition of ADP-Fe induced a further production of pentane which was linear with incubation time. Radiation alone (700 and 2000 Gy) also induced pentane production, but the highest levels were observed with the combination of ADP-Fe and radiation. In microsomes irradiated with 700 Gy, the rate of pentane production was greatest during the first 100 min post-irradiation. In comparing radiation-induced pentane generation to the enzymatic-induced system, it was seen that pentane production was much greater in the latter system.

Physical and chemical interactions at the interface between atmospheric pressure plasmas and aqueous solutions

Science.gov (United States)

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

2014-10-01

Transport and reactions of charged species, neutrals, and photons at the interface between plasmas and liquids must be better quantified. The work presented here combines theoretical and experimental investigations of conditions in the gas and liquid phases in proximity to the interface for various discharges. OES is used to determine rotational and vibrational temperatures of OH, NO, and N2+; the relationship between these temperatures that characterize the distribution of internal energy states and gas and electron kinetic temperatures is considered. The deviation of OH rotational states from equilibrium under high humidity conditions is also presented. In contradiction with findings of other groups, high energy rotational states appear to become underpopulated with increasing humidity. In the aqueous phase, concentrations of longer-lived species such as nitrate, nitrite, hydrogen peroxide, and ozone are determined using ion chromatography and colorimetric methods. Spin-traps and electron paramagnetic resonance (EPR) are investigated for characterization of short-lived aqueous radicals like OH, O2-, NO, and ONOO-. Finally, experimental results are compared to a numerical model which couples transport and reactions within and between the bulk gas and liquid phases.

The dynamics of gas-puff imploding plasmas on the NRL Gamble II Generator

International Nuclear Information System (INIS)

Stephanakis, S.J.; Boller, J.R.; Hinshelwood, D.D.; McDonald, S.W.; Mehlman, C.G.; Ottinger, P.F.; Young, F.C.

1985-01-01

The experimental study of imploding plasma loads on the NRL Gamble II generator was initiated more than a year ago. Preliminary results including scaling laws for K-line radiation output from neon puffs and the effect of plasma erosion opening switches (PEOS's) on the x-ray yields and the pinch quality were reported upon during the past year. In order to better understand the implosion dynamics of such plasmas, time-resolved photographs have been taken of the implosion history. In contrast with time-integrated x-ray pinhole photographs, the time-resolved visible-light pictures indicate that the implosion phase is essentially instability-free, while pinching and flaring occur at late times during the blow-up phase. Furthermore, these visible-light framing photographs clearly show that the discharge is flared out toward the anode at early times and becomes cylindrical at implosion. This so-called ''zipper-effect'' has been seen in previous argon-puff experiments and is due to the non-uniform initial distribution of gas across the anode-cathode gap. The authors present comparisons of time-resolved photographs taken both in visible and x-ray light along with x-ray spectra taken with and without PEOS's. The implications of these data are discussed in view of the present theoretical understanding of the plasma implosion dynamics

The dynamics of gas-puff imploding plasmas on the NRL Gamble II generator

International Nuclear Information System (INIS)

Stephanakis, S.J.; Boller, J.R.; Hinshelwood, D.D.; McDonald, S.W.; Mehlman, C.G.; Ottinger, P.F.; Young, F.C.

1985-01-01

The experimental study of imploding plasma loads on the NRL Gamble II generator was initiated more than a year ago. Preliminary results including scaling laws for K-line radiation output from neon puffs and the effect of plasma erosion opening switches (PEOS's) on the x-ray yields and the pinch quality were reported upon during the past year. In order to better understand the implosion dynamics of such plasmas, time-resolved photographs have been taken of the implosion history. In contrast with time-integrated x-ray pinhole photographs, the time-resolved visible-light pictures indicate that the implosion phase is essentially instability-free, while pinching and flaring occur at late times during the blow-up phase. Furthermore, these visible-light framing photographs clearly show that the discharge is flared out toward the anode at early times and becomes cylindrical at implosion. This so-called ''zipper-effect'' has been seen in previous argon-puff experiments and is due to the non-uniform initial distribution of gas across the anode-cathode gap. The authors present comparisons of time-resolved photographs taken both in visible and x-ray light along with x-ray spectra taken with and without PEOS's. The implications of these data are discussed in view of the present theoretical understanding of the plasma implosion dynamics

Spectroscopic diagnosis of plasma in atmospheric pressure negative pulsed gas-liquid discharge with nozzle-cylinder electrode

Science.gov (United States)

Ming, SUN; Zhan, TAO; Zhipeng, ZHU; Dong, WANG; Wenjun, PAN

2018-05-01

The plasma characteristics of a gas-liquid phase discharge reactor were investigated by optical and electrical methods. The nozzle-cylinder electrode in the discharge reactor was supplied with a negative nanosecond pulsed generator. The optical emission spectrum diagnosis revealed that OH (A2∑+ → X2Π, 306–309 nm), N2 (C3Π→B3Πg, 337 nm), O (3p5p→3s5s0, 777.2 nm) and O (3p3p→3s3s0, 844.6 nm) were produced in the discharge plasma channels. The electron temperature (T e) was calculated from the emission relative intensity ratio between the atomic O 777.2 nm and 844.6 nm, and it increased with the applied voltage and the pulsed frequency and fell within the range of 0.5–0.8 eV. The gas temperature (T g) that was measured by Lifbase was in a range from 400 K to 600 K.

EDITORIAL: Plasma jets and plasma bullets Plasma jets and plasma bullets

Science.gov (United States)

Kong, M. G.; Ganguly, B. N.; Hicks, R. F.

2012-06-01

Plasma plumes, or plasma jets, belong to a large family of gas discharges whereby the discharge plasma is extended beyond the plasma generation region into the surrounding ambience, either by a field (e.g. electromagnetic, convective gas flow, or shock wave) or a gradient of a directionless physical quantity (e.g. particle density, pressure, or temperature). This physical extension of a plasma plume gives rise to a strong interaction with its surrounding environment, and the interaction alters the properties of both the plasma and the environment, often in a nonlinear and dynamic fashion. The plasma is therefore not confined by defined physical walls, thus extending opportunities for material treatment applications as well as bringing in new challenges in science and technology associated with complex open-boundary problems. Some of the most common examples may be found in dense plasmas with very high dissipation of externally supplied energy (e.g. in electrical, optical or thermal forms) and often in or close to thermal equilibrium. For these dense plasmas, their characteristics are determined predominantly by strong physical forces of different fields, such as electrical, magnetic, thermal, shock wave, and their nonlinear interactions [1]. Common to these dense plasma plumes are significant macroscopic plasma movement and considerable decomposition of solid materials (e.g. vaporization). Their applications are numerous and include detection of elemental traces, synthesis of high-temperature materials and welding, laser--plasma interactions, and relativistic jets in particle accelerators and in space [2]-[4]. Scientific challenges in the understanding of plasma jets are exciting and multidisciplinary, involving interweaving transitions of all four states of matter, and their technological applications are wide-ranging and growing rapidly. Using the Web of Science database, a search for journal papers on non-fusion plasma jets reveals that a long initial phase up

Predictable topography simulation of SiO2 etching by C5F8 gas combined with a plasma simulation, sheath model and chemical reaction model

International Nuclear Information System (INIS)

Takagi, S; Onoue, S; Iyanagi, K; Nishitani, K; Shinmura, T; Kanoh, M; Itoh, H; Shioyama, Y; Akiyama, T; Kishigami, D

2003-01-01

We have developed a simulation for predicting reactive ion etching (RIE) topography, which is a combination of plasma simulation, the gas reaction model, the sheath model and the surface reaction model. The simulation is applied to the SiO 2 etching process of a high-aspect-ratio contact hole using C 5 F 8 gas. A capacitively coupled plasma (CCP) reactor of an 8-in. wafer was used in the etching experiments. The baseline conditions are RF power of 1500 W and gas pressure of 4.0 Pa in a gas mixture of Ar, O 2 and C 5 F 8 . The plasma simulation reproduces the tendency that CF 2 radical density increases rapidly and the electron density decreases gradually with increasing gas flow rate of C 5 F 8 . In the RIE topography simulation, the etching profiles such as bowing and taper shape at the bottom are reproduced in deep holes with aspect ratios greater than 19. Moreover, the etching profile, the dependence of the etch depth on the etching time, and the bottom diameter can be predicted by this simulation