Improved parthenogenetic development of vitrified-warmed bovine oocytes activated with 9% ethanol plus 6-DMAP

DEFF Research Database (Denmark)

Hou, Y -p; Liu, Ying; Dai, Y -p

2009-01-01

The objective was to compare various activation protocols on developmental potential of vitrified bovine oocytes. Bovine oocytes matured in vitro for 23 h were vitrified with EDFSF30 in open pulled straws. After warming, they were cultured in vitro for 1 h, followed by parthenogenetic activation....... Vitrified-warmed oocytes had a morphologically normal rate similar to that of controls (nonvitrified oocytes cultured in vitro for 24 h; 98.6% vs. 100%, P > 0.05). When vitrified-warmed oocytes were first activated with 7% ethanol for 5 min and then incubated in 6-dimethylaminopurin (6-DMAP) for 4 h...... (for 5 min) or in combination with 6-DMAP (4 h) was used to activate vitrified-warmed oocytes, cleavage rates ranged from 22.3% to 61.1% and blastocyst rates ranged from 1.1% to 30.6%. These rates were optimized when oocytes were treated with 9% ethanol plus 6-DMAP; this was verified in experiments...

Thermodynamic diagrams for high temperature plasmas of air, air-carbon, carbon-hydrogen mixtures, and argon

CERN Document Server

Kroepelin, H; Hoffmann, K-U

2013-01-01

Thermodynamic Diagrams for High Temperature Plasmas of Air, Air-Carbon, Carbon-Hydrogen Mixtures, and Argon provides information relating to the properties of equilibrium gas plasmas formed from hydrocarbons, from air without argon, from pure argon, and from mixtures of air and carbon at various compositions, temperatures and pressures. The data are presented in graphical rather than tabular form to provide a clearer picture of the plasma processes investigated. This book is composed of four chapters, and begins with the introduction to the characteristics of plasmas, with emphasis on their th

Diagnostics of atmospheric pressure air plasmas

International Nuclear Information System (INIS)

Laux, C.O.; Kruger, C.H.; Zare, R.N.

2001-01-01

Atmospheric pressure air plasmas are often thought to be in Local Thermodynamics Equilibrium (LTE) owing to fast interspecies collisional exchanges at high pressure. As will be seen here, this assumption cannot be relied upon, particularly with respect to optical diagnostics. Large velocity gradients in flowing plasmas and/or elevated electron temperatures created by electrical discharges can result in large departures from chemical and thermal equilibrium. Diagnostic techniques based on optical emission spectroscopy (OES) and Cavity Ring-Down Spectroscopy (CRDS) have been developed and applied at Stanford University to the investigation of atmospheric pressure plasmas under conditions ranging from thermal and chemical equilibrium to thermochemical nonequilibrium. This article presents a review of selected temperature and species concentration measurement techniques useful for the study of air and nitrogen plasmas

Vitrified chemically bonded phosphate ceramics for immobilization of radioisotopes

Science.gov (United States)

Wagh, Arun S.

2016-04-05

A method of immobilizing a radioisotope and vitrified chemically bonded phosphate ceramic (CBPC) articles formed by the method are described. The method comprises combining a radioisotope-containing material, MgO, a source of phosphate, and optionally, a reducing agent, in water at a temperature of less than 100.degree. C. to form a slurry; curing the slurry to form a solid intermediate CBPC article comprising the radioisotope therefrom; comminuting the intermediate CBPC article, mixing the comminuted material with glass frits, and heating the mixture at a temperature in the range of about 900 to about 1500.degree. C. to form a vitrified CBPC article comprising the radioisotope immobilized therein.

Study on behaviour in long term of vitrified materials

International Nuclear Information System (INIS)

Vernaz, E.

1993-01-01

In collaboration with EDF (Electricite de France), after testing fusion of Refiom (Residus d'Epuration des Fumees d'Incineration d'Ordures Menageres), residues from purification of incineration smokes of household rubbish, realised at Porcheville and at the Laboratory of Renardieres with experimental processing of vitrification by plasma, CEA (Centre d'Etudes Atomiques), atomic center of research, began study on resistance in long term of vitrified products. From about thirty five years, CEA carries out research to confine radioactive waste of high activity in stable materials. Glass was the first best one which allowed to incorporate about thirty different chemical elements found in fission products solutions into a stable die with a good chemical durability; three vitrification shops raised, one at Marcoule ('AVM', 1978) in the south of France, the two other ones at La Hague ('R7', 1989 and 'T7', 1992) in Normandy. To determine a possible impact of a deep radioactive waste disposal on human and environment, several studies began. In particular, studies on aqueous corrosion of glasses to determine behaviour in long term of glass package (first barrier of confinement) and to estimate kinetics of releasing confined toxical elements on periods of several thousands years. Principal results are exposed in this conference. Experience shows that safety analysis cannot be based on long term extrapolation of a simple lixiviation result. This analysis must include: a sufficient knowledge in basic mechanisms of alteration to predict the kinetic evolution in a long term. To take in account environment conditions with a normal or accidental scheme (acidity, clay, organic compounds,...). This knowledge broadly developed by CEA for nuclear glasses seems to be easily transposable to different wastes (industrial ones or from hospitals) and takes place in a contract of research CEA/EDF to valorize vitrified products. 9 figs. 4 refs

Pre-disposal storage, transport and handling of vitrified high level waste

International Nuclear Information System (INIS)

Kempe, T.F.; Martin, A.

1981-05-01

The objectives of the study were to review non site-specific engineering features of the storage, transport and handling of vitrified high level radioactive waste prior to its transfer into an underground repository, and to identify those features which require validation or development. Section headings are: introduction (historical and technical background); characteristics and arisings of vitrified high level waste; overpacks (additional containment barrier, corrosion resistant); interim storage of HLW; transport of HLW; handling; conclusions and recommendations. (U.K.)

Information dossier. Return of vitrified wastes from France to Belgium; Dossier d'information. Retour de dechets vitrifies depuis la France vers la Belgique

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-02-01

Synatom, a daughter company of Electrabel and Tractebel, is in charge of the fuel management of Belgium nuclear power plants. Contracts were signed with Cogema (France) in the 70's for the reprocessing/recycling of spent fuels. The ultimate residual wastes are vitrified at Cogema-La Hague and sent back to Belgium by rail and road transports. This information dossier presents: the power production in Belgium, the management of the fuel cycle in Belgium (recycling, interim storage of spent fuels at Tihange and Doel sites, political choices, financing), the vitrification process (quality assurance, safety), the transport of vitrified wastes from France to Belgium (handling, packaging, TN 28 VT container, regulations, safety evaluation), interim storage, long-term disposal. (J.S.)

In-straw cryoprotectant dilution of IVP bovine blastocysts vitrified in hand-pulled glass micropipettes.

Science.gov (United States)

Vieira, A D; Forell, F; Feltrin, C; Rodrigues, J L

2007-06-01

The aim of this study was to determine the influence of two ethylene glycol-based vitrification solutions on in vitro and in vivo survival after in-straw cryoprotectant dilution of vitrified in vitro-produced bovine embryos. Day-7 expanded blastocysts were selected according to diameter (> or = 180 microm) and osmotic characteristics and randomly assigned to one of three groups (i) VSa: vitrification in 40% EG+17.1% SUC+0.1% PVA; (ii) VSb: vitrification in 20% EG+20% DMSO; (iii) control: non-vitrified embryos. Vitrification was performed in hand-pulled glass micropipettes (GMP) and cryoprotectant dilution in 0.25 ml straws after warming in a plastic tube. Embryo viability was assessed by re-expansion and hatching rates after 72 h of IVC and by pregnancy rates after direct transfer of vitrified embryos. No differences in re-expansion rates were observed between vitrified groups after 24 h in culture (VSa=84.5%; VSb=94.8%). However, fewer VSa embryos (55.2%, Pstraw cryoprotectant dilution and direct embryo transfer.

[Experimental study on spectra of compressed air microwave plasma].

Science.gov (United States)

Liu, Yong-Xi; Zhang, Gui-Xin; Wang, Qiang; Hou, Ling-Yun

2013-03-01

Using a microwave plasma generator, compressed air microwave plasma was excited under 1 - 5 atm pressures. Under different pressures and different incident microwave power, the emission spectra of compressed air microwave plasma were studied with a spectra measuring system. The results show that continuum is significant at atmospheric pressure and the characteristic will be weakened as the pressure increases. The band spectra intensity will be reduced with the falling of the incident microwave power and the band spectra were still significant. The experimental results are valuable to studying the characteristics of compressed air microwave plasma and the generating conditions of NO active groups.

Estimation of the heat generation in vitrified waste product and shield thickness of the cask for the transportation of vitrified waste product using Monte Carlo technique

International Nuclear Information System (INIS)

Deepa, A.K.; Jakhete, A.P.; Mehta, D.; Kaushik, C.P.

2011-01-01

High Level Liquid waste (HLW) generated during reprocessing of spent fuel contains most of the radioactivity present in the spent fuel resulting in the need for isolation and surveillance for extended period of time. Major components in HLW are the corrosion products, fission products such as 137 Cs, 90 Sr, 106 Ru, 144 Ce, 125 Sb etc, actinides and various chemicals used during reprocessing of spent fuel. Fresh HLW having an activity concentration of around 100Ci/l is to be vitrified into borosilicate glass and packed in canisters which are placed in S.S overpacks for better confinement. These overpacks contain around 0.7 Million Curies of activity. Characterisation of activity in HLW and activity profile of radionuclides for various cooling periods sets the base for the study. For transporting the vitrified waste product (VWP), two most important parameters is the shield thickness of the transportation cask and the heat generation in the waste product. This paper describes the methodology used in the estimation of lead thickness for the transportation cask using the Monte Carlo Technique. Heat generation due to decay of fission products results in the increase in temperature of the vitrified waste product during interim storage and disposal. Glass being the material, not having very high thermal conductivity, temperature difference between the canister and surrounding bears significance in view of the possibility of temperature based devitrification of VWP. The heat generation in the canister and the overpack containing vitrified glass is also estimated using MCNP. (author)

Properties of thermal air plasma with admixing of copper and carbon

International Nuclear Information System (INIS)

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

2014-01-01

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

Analysis of processes in DC arc plasma torches for spraying that use air as plasma forming gas

International Nuclear Information System (INIS)

Frolov, V; Ivanov, D; Toropchin, A

2014-01-01

Developed in Saint Petersburg State Polytechnical University technological processes of air-plasma spraying of wear-resistant, regenerating, hardening and decorative coatings used in number of industrial areas are described. The article contains examples of applications of air plasma spraying of coatings as well as results of mathematical modelling of processes in air plasma torches for spraying

Pure air-plasma bullets propagating inside microcapillaries and in ambient air

KAUST Repository

Lacoste, Deanna; Bourdon, Anne; Kuribara, Koichi; Urabe, Keiichiro; Stauss, Sven; Terashima, Kazuo

2014-01-01

This paper reports on the characterization of air-plasma bullets in microcapillary tubes and in ambient air, obtained without the use of inert or noble gases. The bullets were produced by nanosecond repetitively pulsed discharges, applied in a dielectric barrier discharge configuration. The anode was a tungsten wire with a diameter of 50 μm, centered in the microcapillary, while the cathode was a silver ring, fixed on the outer surface of the fused silica tube. The effects of the applied voltage and the inner diameter of the microcapillary tube on the plasma behavior were investigated. Inside the tubes, while the topology of the bullets seems to be strongly dependent on the diameter, their velocity is only a function of the amplitude of the applied voltage. In ambient air, the propagation of air bullets with a velocity of about 1.25 ×105 m s-1 is observed.

Pure air-plasma bullets propagating inside microcapillaries and in ambient air

KAUST Repository

Lacoste, Deanna

2014-11-04

This paper reports on the characterization of air-plasma bullets in microcapillary tubes and in ambient air, obtained without the use of inert or noble gases. The bullets were produced by nanosecond repetitively pulsed discharges, applied in a dielectric barrier discharge configuration. The anode was a tungsten wire with a diameter of 50 μm, centered in the microcapillary, while the cathode was a silver ring, fixed on the outer surface of the fused silica tube. The effects of the applied voltage and the inner diameter of the microcapillary tube on the plasma behavior were investigated. Inside the tubes, while the topology of the bullets seems to be strongly dependent on the diameter, their velocity is only a function of the amplitude of the applied voltage. In ambient air, the propagation of air bullets with a velocity of about 1.25 ×105 m s-1 is observed.

Air plasma processing of poly(methyl methacrylate) micro-beads: Surface characterisations

International Nuclear Information System (INIS)

Liu Chaozong; Cui Naiyi; Osbeck, Susan; Liang He

2012-01-01

Highlights: ► PMMA micro-beads were processed using a rotary air plasma reactor. ► Surface chemistry and surface texture of PMMA micro-beads were characterised. ► Surface wettability was evaluated using “floating” water contact angle method. ► Surface oxidation and texture changes induced by air plasma attributed to the improvement of surface wettability. - Abstract: This paper reports the surface processing of poly(methyl methacrylate) (PMMA) micro-beads by using a rotary air plasma reactor, and its effects on surface properties. The surface properties, including surface wettability, surface chemistry and textures of the PMMA beads, were characterised. It was observed that the air plasma processing can improve the surface wettability of the PMMA microbeads significantly. A 15 min plasma processing can reduce the surface water contact angle of PMMA beads to about 50° from its original value of 80.3°. This was accompanied by about 8% increase in surface oxygen concentration as confirmed by XPS analysis. The optical profilometry examination revealed the air plasma processing resulted in a rougher surface that has a “delicate” surface texture. It is concluded that the surface chemistry and texture, induced by air plasma processing, co-contributed to the surface wettability improvement of PMMA micro-beads.

Electron-Beam Produced Air Plasma: Optical Measurement of Beam Current

Science.gov (United States)

Vidmar, Robert; Stalder, Kenneth; Seeley, Megan

2006-10-01

Experiments to quantify the electron beam current and distribution of beam current in air plasma are discussed. The air plasma is produced by a 100-keV 10-mA electron beam source that traverses a transmission window into a chamber with air as a target gas. Air pressure is between 1 mTorr and 760 Torr. Strong optical emissions due to electron impact ionization are observed for the N2 2^nd positive line at 337.1 nm and the N2^+ 1^st negative line at 391.4 nm. Calibration of optical emissions using signals from the isolated transmission window and a Faraday plate are discussed. The calibrated optical system is then used to quantify the electron distribution in the air plasma.

Measurement of air entrainment in plasma jets

International Nuclear Information System (INIS)

Fincke, J.R.; Rodriquez, R.; Pentecost, C.G.

1990-01-01

The concentration and temperature of air entrained into argon and helium plasma jets has been measured using coherent anti-Stokes Raman spectroscopy (CARS). The argon plasma flow field is characterized by a short region of well behaved laminar flow near the nozzle exit followed by an abrupt transition to turbulence. Once the transition of turbulence occurs, air is rapidly mixed into the jet core. The location of the transition region is determined by the rapid cooling of the jet and the resulting increase in Reynolds number. In contrast, the helium plasma flow field never exceeds a Reynolds number of 200 and remains laminar. The entrainment process in this case is controlled by molecular diffusion rather than turbulent mixing. 9 refs., 5 figs., 1 tab

Source term measurements on vitrified HLW

International Nuclear Information System (INIS)

Hough, A.; Marples, J.A.C.

1988-01-01

The equilibrium concentrations of Tc-99, Np-237, Pu-239/240 and Am-241 have been measured in the presence of materials likely to be present in a vitrified HLW repository: glass, iron, backfill and rock. Results were measured under both oxidising and reducing conditions and at pH values set by the backfill bentonite and cement. Under reducing conditions and with cementitious backfills, the equilibrium concentrations ranged from three to 30 times allowed drinking water levels for the four isotopes. (author)

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

Science.gov (United States)

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

2010-10-15

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

Mixed Wastes Vitrification by Transferred Plasma

International Nuclear Information System (INIS)

Tapia-Fabela, J.; Pacheco-Pacheco, M.; Pacheco-Sotelo, J.; Torres-Reyes, C.; Valdivia-Barrientos, R.; Benitez-Read, J.; Lopez-Callejas, R.; Ramos-Flores, F.; Boshle, S.; Zissis, G.

2007-01-01

Thermal plasma technology provides a stable and long term treatment of mixed wastes through vitrification processes. In this work, a transferred plasma system was realized to vitrify mixed wastes, taking advantage of its high power density, enthalpy and chemical reactivity as well as its rapid quenching and high operation temperatures. To characterize the plasma discharge, a temperature diagnostic is realized by means of optical emission spectroscopy (OES). To typify the morphological structure of the wastes samples, scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques were applied before and after the plasma treatment

Air plasma effect on dental disinfection

International Nuclear Information System (INIS)

Duarte, S.; Murata, R. M.; Saxena, D.; Kuo, S. P.; Chen, C. Y.; Huang, K. J.; Popovic, S.

2011-01-01

A nonthermal low temperature air plasma jet is characterized and applied to study the plasma effects on oral pathogens and biofilms. Experiments were performed on samples of six defined microorganisms' cultures, including those of gram-positive bacteria and fungi, and on a cultivating biofilm sample of Streptococcus mutans UA159. The results show that the plasma jet creates a zone of microbial growth inhibition in each treated sample; the zone increases with the plasma treatment time and expands beyond the entire region directly exposed to the plasma jet. With 30s plasma treatment twice daily during 5 days of biofilm cultivation, its formation was inhibited. The viability of S. mutans cells in the treated biofilms dropped to below the measurable level and the killed bacterial cells concentrated to local regions as manifested by the fluorescence microscopy via the environmental scanning electron microscope. The emission spectroscopy of the jet indicates that its plasma effluent carries an abundance of reactive atomic oxygen, providing catalyst for the observed plasma effect.

Air plasma effect on dental disinfection

Science.gov (United States)

Duarte, S.; Kuo, S. P.; Murata, R. M.; Chen, C. Y.; Saxena, D.; Huang, K. J.; Popovic, S.

2011-07-01

A nonthermal low temperature air plasma jet is characterized and applied to study the plasma effects on oral pathogens and biofilms. Experiments were performed on samples of six defined microorganisms' cultures, including those of gram-positive bacteria and fungi, and on a cultivating biofilm sample of Streptococcus mutans UA159. The results show that the plasma jet creates a zone of microbial growth inhibition in each treated sample; the zone increases with the plasma treatment time and expands beyond the entire region directly exposed to the plasma jet. With 30s plasma treatment twice daily during 5 days of biofilm cultivation, its formation was inhibited. The viability of S. mutans cells in the treated biofilms dropped to below the measurable level and the killed bacterial cells concentrated to local regions as manifested by the fluorescence microscopy via the environmental scanning electron microscope. The emission spectroscopy of the jet indicates that its plasma effluent carries an abundance of reactive atomic oxygen, providing catalyst for the observed plasma effect.

Neonatal health including congenital malformation risk of 1072 children born after vitrified embryo transfer.

Science.gov (United States)

Belva, F; Bonduelle, M; Roelants, M; Verheyen, G; Van Landuyt, L

2016-07-01

Does vitrification of Day 3 and Day 5 embryos adversely affect birth outcomes of singletons and twins in comparison with peers born after fresh embryo transfer? Neonatal health parameters, including the prevalence of congenital malformations, in singletons and twins born after embryo vitrification are similar to or slightly better than after fresh embryo transfer. Although vitrification, rather than slow-freezing, of embryos is routine practice nowadays, convincing evidence regarding the safety for the offspring is sparse. Literature data comprise results from mostly small-sized studies or studies including only Day 3 or only Day 5 vitrified embryo transfers. Overall, better or comparable perinatal outcomes, in terms of higher birthweight and lower risk for small-for-gestational age or for low birthweight, have been reported for singletons born after vitrified embryo transfer compared with fresh embryo transfer. According to the single available study with sufficient sample size, the congenital malformation rate was found to be comparable after vitrified and fresh embryo transfers. Data were collected from 960 cycles after transfer of embryos vitrified on Day 3 (n = 457) or Day 5 (n = 503) and from 1644 cycles after fresh embryo transfer on Day 3 (n = 853) or Day 5 (n = 791), performed between 2008 and 2013 at the Centre for Reproductive Medicine of the university hospital UZ Brussel. Outcome measures were neonatal health in terms of birthweight, small-for-gestational age, prematurity rate, perinatal death and major/minor/total malformation rate. Perinatal health parameters of 11 stillborns and 1061 live borns (827 singletons and 234 twins) in the vitrified group and of 28 stillborns and 1838 live borns (1374 singletons and 464 twins) in the fresh embryo group are reported. Within 3 months after birth, children in the two study groups were assessed clinically with special attention to congenital malformations by a paediatrician blinded to the type of embryo

Safety of handling, storing and transportation of spent nuclear fuel and vitrified high-level wastes

International Nuclear Information System (INIS)

Ericsson, A.M.

1977-11-01

The safety of handling and transportation of spent fuel and vitrified high-level waste has been studied. Only the operations which are performed in Sweden are included. That is: - Transportation of spent fuel from the reactors to an independant spent fuel storage installation (ISFSI). - Temporary storage of spent fuel in the ISFSI. - Transportation of the spent fuel from the ISFSI to a foreign reprocessing plant. - Transportation of vitrified high-level waste to an interim storage facility. - Interim storage of vitrified high-level waste. - Handling of the vitrified high-level waste in a repository for ultimate disposal. For each stage in the handling sequence above the following items are given: - A brief technical description. - A description of precautionary measures considered in the design. - An analysis of the discharges of radioactive materials to the environment in normal operation. - An analysis of the discharges of radioactive materials due to postulated accidents. The dose to the public has been roughly and conservatively estimated for both normal and accident conditions. The expected rate of occurence are given for the accidents. The results show that above described handling sequence gives only a minor risk contribution to the public

Studies of air plasma techniques in mutating Penicillium chrysogenum

International Nuclear Information System (INIS)

Gui Fang; Liu Hui; Wang Hui; Wang Peng; Yuan Chengling; Zheng Zhiming

2011-01-01

penicillin producing strain Penicillium chrysogenum Pc05 as the starting strain was mutated by low-temperature air plasma technology. As the result revealed, in 30 minutes, the survival rate of spores followed the saddle-shaped curve. The positive mutants accounted for 44.19% of all mutants while the negative mutation was low. After primary and secondary screening, the mutant aPc051310 was obtained, and eventually its penicillin titer increased 42.1% compared with that of starting strain. Synergetic effect between chemical reactive species and charged particles was considered as the main mutation mechanism involved in low temperature air plasma. All the results have been proved that as a new industrial microbial strains mutation method, low temperature air plasma has potential applications. (authors)

Pure rotational CARS thermometry studies of low-temperature oxidation kinetics in air and ethene-air nanosecond pulse discharge plasmas

International Nuclear Information System (INIS)

Zuzeek, Yvette; Choi, Inchul; Uddi, Mruthunjaya; Adamovich, Igor V; Lempert, Walter R

2010-01-01

Pure rotational CARS thermometry is used to study low-temperature plasma assisted fuel oxidation kinetics in a repetitive nanosecond pulse discharge in ethene-air at stoichiometric and fuel lean conditions at 40 Torr pressure. Air and fuel-air mixtures are excited by a burst of high-voltage nanosecond pulses (peak voltage, 20 kV; pulse duration, ∼ 25 ns) at a 40 kHz pulse repetition rate and a burst repetition rate of 10 Hz. The number of pulses in the burst is varied from a few pulses to a few hundred pulses. The results are compared with the previously developed hydrocarbon-air plasma chemistry model, modified to incorporate non-empirical scaling of the nanosecond discharge pulse energy coupled to the plasma with number density, as well as one-dimensional conduction heat transfer. Experimental time-resolved temperature, determined as a function of the number of pulses in the burst, is found to agree well with the model predictions. The results demonstrate that the heating rate in fuel-air plasmas is much faster compared with air plasmas, primarily due to energy release in exothermic reactions of fuel with O atoms generated by the plasma. It is found that the initial heating rate in fuel-air plasmas is controlled by the rate of radical (primarily O atoms) generation and is nearly independent of the equivalence ratio. At long burst durations, the heating rate in lean fuel air-mixtures is significantly reduced when all fuel is oxidized.

High-efficiency plasma catalytic removal of dilute benzene from air

International Nuclear Information System (INIS)

Fan, Hong-Yu; Shi, Chuan; Li, Xiao-Song; Zhao, De-Zhi; Xu, Yong; Zhu, Ai-Min

2009-01-01

Achieving complete oxidation, good humidity tolerance and low energy cost is the key issue that needs to be addressed in plasma catalytic volatile organic compounds removal from air. For this purpose, Ag/HZSM-5 catalyst-packed dielectric barrier discharge using a cycled system composed of a storage stage and a discharge stage was studied. For dilute benzene removal from simulated air, Ag/HZSM-5 catalysts exhibit not only preferential adsorption of benzene in humid air at the storage stage but also almost complete oxidation of adsorbed benzene at the discharge stage. Five 'storage-discharge' cycles were examined, which suggests that Ag/HZSM-5 catalysts are very stable during the cycled 'storage-discharge' (CSD) plasma catalytic process. High oxidation rate of absorbed benzene as well as low energy cost can be achieved at a moderate discharge power. In an example of the CSD plasma catalytic remedy of simulated air containing 4.7 ppm benzene with 50% RH and 600 ml min -1 flow rate, the energy cost was as low as 3.7 x 10 -3 kWh m -3 air. This extremely low energy cost to remove low-concentration pollutants from air undoubtedly makes the environmental applications of the plasma catalytic technique practical.

Air plasma effect on dental disinfection

Energy Technology Data Exchange (ETDEWEB)

Duarte, S.; Murata, R. M.; Saxena, D. [Department of Basic Sciences and Craniofacial Biology, College of Dentistry, New York University, New York, New York 10010 (United States); Kuo, S. P.; Chen, C. Y.; Huang, K. J. [Department of Electrical and Computer Engineering, Polytechnic Institute of New York University, Brooklyn, New York 11202 (United States); Popovic, S. [Department of Physics, Old Dominion University, Norfolk, Virginia 23529 (United States)

2011-07-15

A nonthermal low temperature air plasma jet is characterized and applied to study the plasma effects on oral pathogens and biofilms. Experiments were performed on samples of six defined microorganisms' cultures, including those of gram-positive bacteria and fungi, and on a cultivating biofilm sample of Streptococcus mutans UA159. The results show that the plasma jet creates a zone of microbial growth inhibition in each treated sample; the zone increases with the plasma treatment time and expands beyond the entire region directly exposed to the plasma jet. With 30s plasma treatment twice daily during 5 days of biofilm cultivation, its formation was inhibited. The viability of S. mutans cells in the treated biofilms dropped to below the measurable level and the killed bacterial cells concentrated to local regions as manifested by the fluorescence microscopy via the environmental scanning electron microscope. The emission spectroscopy of the jet indicates that its plasma effluent carries an abundance of reactive atomic oxygen, providing catalyst for the observed plasma effect.

TNTM85 and TNTM81 transports / storage flasks: An optimized solution for vitrified residues

International Nuclear Information System (INIS)

Sicard, D.; Verdier, A.; Dyck, P.

2006-01-01

By analyzing the evolution of burnup of spent fuel to be reprocessed, the high activity vitrified residues would not be transported in the existing flask designs. Therefore COGEMA LOGISTICS decided in the late nineties to develop a design with optimized capacity able to store and transport the most active and hottest canisters. The TN TM 85 flask shall permit in the near future in Germany the storage and the transport of the highest vitrified residues defining a thermal power of 56 kW. The challenge for the TN TM 85 flask design was that the geometry entry data were very restrictive and were combined with a fairly wide range set by COGEMA Specification 300AQ16 relative to vitrified residue canister. In addition, the cask had to fit as much as possible in the existing procedures for the TN TM 28 cask and TS 28 V cask, all along the logistics chain of loading, unloading, transport and maintenance. (authors)

Low temperature irradiation of vitrifiable mixtures of unsaturated monomers

International Nuclear Information System (INIS)

Kaetsu, I.; Ito, A.; Hayashi, K.

1975-01-01

A specific mixture containing at least one polymerizable unsaturated monomer which is not vitrifiable by itself can advantageously be polymerized by irradiating the mixture at a temperature not higher than 100 0 C above glass transition temperature of the mixture with an ionizing radiation and/or a light. 12 claims, 6 drawings, figures

An ecotoxic risk assessment of residue materials produced by the plasma pyrolysis/vitrification (PP/V) process.

Science.gov (United States)

Lapa, N; Santos, Oliveira J F; Camacho, S L; Circeo, L J

2002-01-01

Plasma is the fourth state of matter, following the three states of solid, liquid and gas. Experience has amply demonstrated that solids exposed to the oxygen-deficient plasma flame are converted to liquid, and liquid exposed to the same flame is converted to gas. A low amount of vitrified solid residue material usually remains at the end of this process. Plasma pyrolysis/vitrification (PP/V) has been demonstrated as a safe, efficient, cost-effective technology for the treatment of wastes, including hazardous wastes. Besides the low amounts of gaseous byproducts that PP/V produces, the solid vitrified residue presents a low leachability of pollutants. Studies have been performed in many countries in order to assess the leachability of chemical substances. But from the results of identified studies, none has reported results on the ecotoxicological properties of the leachates. The aim of this study was to contribute to the assessment of ecotoxic risk of four different vitrified materials. Vitrified samples of contaminated soils, municipal solid wastes, and incinerator bottom ashes were submitted to the European leaching pre-standard test number prEN 12457-2. The leachates were analyzed for 22 chemical parameters. The biological characterization comprised the assessment of bioluminescence inhibition of Photobacterium phosphoreum bacterium, growth inhibition of Pseudokirchneriella subcapitata algae and the germination inhibition of Lactuca sativa vegetable. The chemical and ecotoxicological results were analyzed according to the French proposal of Criteria on the Evaluation Methods of Waste Toxicity (CEMWT) and a Toxicity Classification System (TCS). The chemical and ecotoxicological results indicated a low leachability of pollutants and a low toxicity level of leachates. All samples studied were as below the TCS class 1 level (no significant toxicity observed) and as non-ecotoxic for CEMWT. Therefore, the environmental ecotoxic risk of the analyzed vitrified samples

Plasma gasification process: Modeling, simulation and comparison with conventional air gasification

International Nuclear Information System (INIS)

Janajreh, Isam; Raza, Syed Shabbar; Valmundsson, Arnar Snaer

2013-01-01

Highlights: ► Plasma/conventional gasification are modeled via Gibbs energy minimization. ► The model is applied to wide range of feedstock, tire, biomass, coal, oil shale. ► Plasma gasification show high efficiency for tire waste and coal. ► Efficiency is around 42% for plasma and 72% for conventional gasification. ► Lower plasma gasification efficiency justifies hazardous waste energy recovery. - Abstract: In this study, two methods of gasification are developed for the gasification of various feedstock, these are plasma gasification and conventional air gasification. The two methods are based on non-stoichiometric Gibbs energy minimization approach. The model takes into account the different type of feedstocks, which are analyzed at waste to energy lab at Masdar Institute, oxidizer used along with the plasma energy input and accurately evaluates the syngas composition. The developed model is applied for several types of feedstock, i.e. waste tire material, coal, plywood, pine needles, oil shale, and municipal solid waste (MSW), algae, treated/untreated wood, instigating air/steam as the plasma gas and only air as oxidizer for conventional gasification. The results of plasma gasification and conventional air gasification are calculated on the bases of product gas composition and the process efficiency. Results of plasma gasification shows that high gasification efficiency is achievable using both tire waste material and coal, also, the second law efficiency is calculated for plasma gasification that shows a relative high efficiency for tire and coal as compare to other feedstock. The average process efficiency for plasma gasification is calculated to be around 42%. On other hand the result of conventional gasification shows an average efficiency of 72%. The low efficiency of plasma gasification suggest that if only the disposal of hazard waste material is considered then plasma gasification can be a viable option to recover energy.

A handheld low temperature atmospheric pressure air plasma gun for nanomaterial synthesis in liquid phase

Energy Technology Data Exchange (ETDEWEB)

Yu, Shuang; Wang, Kaile; Zuo, Shasha; Liu, Jiahui [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zhang, Jue, E-mail: zhangjue@pku.edu.cn; Fang, Jing [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China)

2015-10-15

A handheld low temperature atmospheric pressure air plasma gun based on a dielectric barrier structure with hollow electrodes was proposed. The portable plasma gun with an embedded mini air pump was driven by a 12 V direct voltage battery. The air plasma jet generated from the gun could be touched without a common shock hazard. Besides working in air, the plasma gun can also work in water. The diagnostic result of optical emission spectroscopy showed the difference in reactive species of air plasma jet between in air and in water. The plasma gun was excited in 20 ml chloroauric acid aqueous solution with a concentration of 1.214 mM. A significant amount of gold nanoparticles were synthesized after 2 min continuous discharge. The plasma gun with these unique features is applicable in plasma medicine, etching, and s-nthesis of nanomaterials.

Intermediate storage facility for vitrified high level waste from the reprocessing of spent nuclear fuel

International Nuclear Information System (INIS)

1978-04-01

An intermediate storage facility for vitrified high level waste is described. The design was made specifically for Swedish conditions but can due to modular design be applied also for other conditions. Most of the plant is located underground with a rock cover of about 30 m in order to provide protection against external forces such as acts of war and sabotage. The storage area consists of four caverns each with 150 pits. Each pit can take 10 waste cylinders of 0.4 m diameter and 1.5 m length containing 150 liters of glass. The capacity can be increased by adding additional caverns. Cooling is obtained by forced air convection. Reception areas, auxiliary systems and operation of the plant are also described

Piglets produced by transfer of vitrified porcine embryos after stepwise dilution of cryoprotectants.

Science.gov (United States)

Kobayashi, S; Takei, M; Kano, M; Tomita, M; Leibo, S P

1998-02-01

A total of 498 porcine embryos at various stages of development collected from superovulated gilts was used to investigate cryopreservation. First, blastocysts (BL), expanded blastocysts (ExB), and hatched blastocysts (HB) were used to determine the effect of exposure to concentrated solutions of ethylene glycol as cryoprotective additives (CPAs) on embryo survival. Then, survival of other embryos after vitrification by rapid cooling was determined. Based on their development after 48 h in culture, embryos were not injured by being exposed to 2.0 M ethylene glycol (EG) for 15 min or to 2.0 M EG for 5 min and then to a solution of 8.0 M EG in 7% polyvinylpyrrolidone (PVP) for 1 min. The CPAs were removed from the embryos by diluting them with 1.7 M galactose. To vitrify the embryos, they were exposed to 2.0 M EG for 5 min and then were pipetted directly into short columns of 8.0 M EG-PVP contained within (1.25-ml plastic straws and separated from long columns of 1.7 M galactose by an air bubble. The straws were plunged directly into LN2. After the straws were warmed rapidly in a 25 degrees C water bath, the embryos were immediately mixed with galactose within the straws by shaking them vigorously to mix the contents. In sequential experiments, three methods were used to dilute the CPA solutions. Method 1: Embryos in the EG-PVP-galactose mixture were expelled from the straws and rinsed and cultured in modified CZB medium (mCZB). Method II: Embryos in the mixture were placed briefly into 1.5 M EG and then rinsed and cultured in mCZB. Method III: Embryos in the mixture were rinsed in 1.0 M EG and then in 0.5 M EG and finally rinsed with mCZB and cultured. After 48 h in culture, the respective percentages of survival of embryos vitrified as BL, ExB, or HB were: Method I, 21, 32, and 13%; Method II, 9, 40, and 24%; Method III, 35, 85, and 71%. Of 20 additional ExB vitrified embryos diluted by Method III and transferred into a recipient, four developed into live piglets

Properties of CuS thin films treated in air plasma

International Nuclear Information System (INIS)

Rodriguez-Lazcano, Y.; Martinez, H.; Calixto-Rodriguez, M.; Nunez Rodriguez, A.

2009-01-01

Copper sulfide thin films were grown by chemical deposition and post treated in air plasma during 20 min. Air plasma was generated by alternating current discharge at a pressure of 4 x 10 2 Pa. The power discharge was maintained at an output of 220 V and a current of 0.2 A. Thermal annealing at 300 o C was performed for comparison. X-ray diffraction shows that plasma treatment results in phase transformation of Cu 39 S 28 (as grown) to CuS (treated by plasma). The copper lost is confirmed by X-ray fluorescence. No significant change in the optical band gap was observed due to plasma action. In addition, the electrical conductivity increases in one order of magnitude. On the other hand, the samples under plasma condition show a parallel growth to the substrate and an increase in the surface uniformity. The plasma etching removes copper due to its affinity with oxygen to form CuO, as is corroborated by optical emission spectroscopy.

Porous materials produced from incineration ash using thermal plasma technology.

Science.gov (United States)

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

2014-06-01

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

Providing flexibility in spent fuel and vitrified waste management

International Nuclear Information System (INIS)

Bradley, N.; O'Tallamhain, C.; Brown, G.A.

1986-01-01

The UK Central Electricity Generating Board is pondering a decision to build a dry vault store as a buffer in its overall AGR spent fuel management programme. The application of the dry vault is not limited to fuel from gas cooled reactors, it can be used for spent LWR fuel and vitrified waste. A cutaway diagram of such a vault is presented. (UK)

Stabilization of vitrified wastes: Task 4. Topical report, October 1994--September 1995

International Nuclear Information System (INIS)

Nowok, J.W.; Pflughoeft-Hassett, D.F.; Hassett, D.J.; Hurley, J.P.

1995-09-01

The goal of this task was to work with private industry to refine existing vitrification processes to produce a more stable vitrified product. The initial objectives were to (1) demonstrate a waste vitrification procedure for enhanced stabilization of waste materials and (2) develop a testing protocol to understand the long-term leaching behavior of the stabilized waste form. The testing protocol was expected to be based on a leaching procedure called the synthetic groundwater leaching procedure (SGLP). This task will contribute to the US DOE's identified technical needs in waste characterization, low-level mixed-waste processing, disposition technology, and improved waste forms. The proposed work was to proceed over 4 years in the following steps: literature surveys to aid in the selection and characterization of test mixtures for vitrification, characterization of optimized vitrified test wastes using advanced leaching protocols, and refinement and demonstration of vitrification methods leading to commercialization. For this year, literature surveys were completed, and computer modeling was performed to determine the feasibility of removing heavy metals from a waste during vitrification, thereby reducing the hazardous nature of the vitrified material and possibly producing a commercial metal concentrate. This report describes the following four subtasks: survey of vitrification technologies; survey of cleanup sites; selection and characterization of test mixtures for vitrification and crystallization; and selection of crystallization methods based on thermochemistry modeling

Qualification of a Vitrified High Level Waste Product to Support Used Nuclear Fuel Recycling in the US

International Nuclear Information System (INIS)

Murray, P.; Bailly, F.; Strachan, D.; Senentz, G.; Veyer, C.

2009-01-01

As part of the Department of Energy (DOE) Global Nuclear Energy Partnership (GNEP), AREVA formed the International Nuclear Recycling Alliance (INRA) consisting of recognized world-leading companies in the area of used nuclear fuel (UNF) recycling,. The INRA team, consisting of AREVA, Mitsubishi Heavy Industries (MHI), Japan Nuclear Fuel Ltd (JNFL), Batelle Memorial Institute (BMI), URS Washington Division and Babcock and Wilcox (B and W), prepared a pre-conceptual design for an upgradable engineering-scale recycling plant with a nominal through put of 800 tHM/y. The pre-conceptual design of this leading-edge facility was based upon the extensive experience of the INRA team in recycling plant design and real world 'lessons learned' from actually building, commissioning, and operating recycling facilities in both France and Japan. The conceptual flowsheet, based upon the COEX TM separations process, separates the useful products for recycling into new fuel and sentences all the remaining fission products and minor actinides (MA) to the high level waste, (HLW) for vitrification. The proposed vitrified waste product will be similar to that currently produced in recycling plants in France. This wasteform has been qualified in France by conducting extensive studies and demonstrations. In the US, the qualification of vitrified glass products has been conducted by the US National Laboratories for the Defence Waste Processing Facility (DWPF), the West Valley Demonstration Plant (WVDP), and the Waste Treatment Plant (WTP). The vitrified waste product produced by recycling is sufficiently different from these current waste forms to warrant additional trials and studies. In this paper we review the differences in the vitrified waste forms previously qualified in the US with that produced from recycling of UNF in France. The lessons learned from qualifying a vitrified waste form in Europe is compared to the current US process for vitrified waste qualification including waste

Optical diagnostics of atmospheric pressure air plasmas

International Nuclear Information System (INIS)

Laux, C O; Spence, T G; Kruger, C H; Zare, R N

2003-01-01

Atmospheric pressure air plasmas are often thought to be in local thermodynamic equilibrium owing to fast interspecies collisional exchange at high pressure. This assumption cannot be relied upon, particularly with respect to optical diagnostics. Velocity gradients in flowing plasmas and/or elevated electron temperatures created by electrical discharges can result in large departures from chemical and thermal equilibrium. This paper reviews diagnostic techniques based on optical emission spectroscopy and cavity ring-down spectroscopy that we have found useful for making temperature and concentration measurements in atmospheric pressure plasmas under conditions ranging from thermal and chemical equilibrium to thermochemical nonequilibrium

Effect of air gap on uniformity of large-scale surface-wave plasma

International Nuclear Information System (INIS)

Lan Chaohui; Hu Xiwei; Jiang Zhonghe; Liu Minghai

2009-01-01

The effect of air gap on the uniformity of large-scale surface-wave plasma (SWP) in a rectangular chamber device is studied by using three-dimensional numerical analyses based on the finite difference time-domain (FDTD) approximation to Maxwell's equations and plasma fluid model. The spatial distributions of surface wave excited by slot-antenna array and the plasma parameters such as electron density and temperature are presented. For different air gap thicknesses, the results show that the existence of air gap would severely weaken the excitations of the surface wave and thereby the SWP. Thus the air gap should be eliminated completely in the design of the SWP source, which is opposite to the former research results. (authors)

The Effect of Air Plasma on Sterilization of Escherichia coli in Dielectric Barrier Discharge

International Nuclear Information System (INIS)

Hu Miao; Guo Yun

2012-01-01

In this work, a Dielectric Barrier Discharge (DBD) air plasma was used to sterilize Escherichia coli (E. coli) on the surface of medical Polyethylene Terephthalate (PET) film. The leakage of cellular DNA and protein by optical absorbance measurement at 260 nm and 280 nm, together with transmission electron microscopy (TEM) about cell morphology were performed after sterilization to analyse inactivation mechanisms. The results indicated that the DBD air plasma was very effective in E. coli sterilization. The plasma germicidal efficiency depended on the plasma treatment time, the air-gap distance, and the applied voltage. Within 5 min of plasma treatment, the germicidal efficiency against E. coli could reach 99.99%. An etching action on cell membranes by electrons, ions and radicals is the primary mechanism for DBD air plasma sterilization, which leads to the effusion of cellular contents (DNA and protein) and bacterial death. (plasma technology)

Emission characteristics of kerosene-air spray combustion with plasma assistance

Directory of Open Access Journals (Sweden)

Xingjian Liu

2015-09-01

Full Text Available A plasma assisted combustion system for combustion of kerosene-air mixtures was developed to study emission levels of O2, CO2, CO, and NOx. The emission measurement was conducted by Testo 350-Pro Flue Gas Analyzer. The effect of duty ratio, feedstock gas flow rate and applied voltage on emission performance has been analyzed. The results show that O2 and CO emissions reduce with an increase of applied voltage, while CO2 and NOx emissions increase. Besides, when duty ratio or feedstock gas flow rate decreases, the same emission results would appear. The emission spectrum of the air plasma of plasma assisted combustion actuator was also registered to analyze the kinetic enhancement effect of plasma, and the generation of ozone was believed to be the main factor that plasma makes a difference in our experiment. These results are valuable for the future optimization of kerosene-fueled aircraft engine when using plasma assisted combustion devices to exert emission control.

Feasibility study on utilization of vitrified radioactive waste as radiation sources

International Nuclear Information System (INIS)

Makuuchi, Keizo; Yoshii, Fumio; Hyakutake, Kenichiro

1995-01-01

A feasibility study on utilization of vitrified high level radioactive waste (VW) as radiation source has been carried out. Natural rubber latex was radiation vulcanized with VW to demonstrate the feasibility. The dose rate was 0.1 kGy/hr. As a sensitizer, n-butyl acrylate was added. Negligible small activation of natural rubber (NR) latex by neutron from the VW was observed. The residual sensitizer in the irradiated latex and physical properties of film molded from the irradiated latex were the same level with the conventional radiation vulcanization of NR latex with γ-rays from Co-60. Surgical gloves and protective rubber gloves for radioactive contamination were produced from 20 litters of NR latex vulcanized with 2 VWs. The physical properties of both gloves were acceptable. These results suggested that vitrified high level waste can be used as an industrial radiation source. (author)

Thermal test and analysis for transporting vitrified high-level radioactive wastes

International Nuclear Information System (INIS)

Yamakawa, H.; Gomi, Y.; Ozaki, S.; Kato, O.; Tamaki, H.

1993-01-01

As a part of the safety demonstration tests for transport casks of high level radioactive vitrified wastes, the thermal tests of the cask (left unattended at an ambient temperature of 38degC for a period of one week) were executed before and after the side free drop test (from height of 30 cm). This condition was set according to the prospect of the damage of contents (baskets, etc.) by the impact force at the drop test. It was shown that the cask temperatures at the representative parts, such as the vitrified wastes, the containment system, and the protection wire net, were lower than allowable values. From the result of measured temperatures it was considered that no damages and no large deformations could happen to the contents in this drop test. Thermal analysis was also done to establish the analysis model. (J.P.N.)

Studying the fate of non-volatile organic compounds in a commercial plasma air purifier

Energy Technology Data Exchange (ETDEWEB)

Schmid, Stefan [ETH Zürich, Department of Chemistry and Applied Biosciences, CH-8093 Zürich (Switzerland); Seiler, Cornelia; Gerecke, Andreas C. [Swiss Federal Laboratories for Material Science and Technology (EMPA), CH-8600 Dübendorf (Switzerland); Hächler, Herbert [University of Zürich, Institute for Food Safety and Hygiene, National Centre for Enteropathogenic Bacteria and Listeria (NENT), CH-8057 Zürich (Switzerland); Hilbi, Hubert [Ludwig-Maximilians-Universität München Max von Pettenkofer-Institut, D-80336 München (Germany); Frey, Joachim [University of Bern, Institute for Veterinary Bacteriology, CH-3001 Bern (Switzerland); Weidmann, Simon; Meier, Lukas; Berchtold, Christian [ETH Zürich, Department of Chemistry and Applied Biosciences, CH-8093 Zürich (Switzerland); Zenobi, Renato, E-mail: zenobi@org.chem.ethz.ch [ETH Zürich, Department of Chemistry and Applied Biosciences, CH-8093 Zürich (Switzerland)

2013-07-15

Highlights: • Degradation of environmental toxins, a protein, and bioparticles were studied. • A commercial air purifier based on a cold plasma was used. • Passage through the device reduced the concentration of the compounds/particles. • Deposition inside the plasma air purifier was the main removal process. -- Abstract: Degradation of non-volatile organic compounds–environmental toxins (methyltriclosane and phenanthrene), bovine serum albumin, as well as bioparticles (Legionella pneumophila, Bacillus subtilis, and Bacillus anthracis)–in a commercially available plasma air purifier based on a cold plasma was studied in detail, focusing on its efficiency and on the resulting degradation products. This system is capable of handling air flow velocities of up to 3.0 m s{sup −1} (3200 L min{sup −1}), much higher than other plasma-based reactors described in the literature, which generally are limited to air flow rates below 10 L min{sup −1}. Mass balance studies consistently indicated a reduction in concentration of the compounds/particles after passage through the plasma air purifier, 31% for phenanthrene, 17% for methyltriclosane, and 80% for bovine serum albumin. L. pneumophila did not survive passage through the plasma air purifier, and cell counts of aerosolized spores of B. subtilis and B. anthracis were reduced by 26- and 15-fold, depending on whether it was run at 10 Hz or 50 Hz, respectively. However rather than chemical degradation, deposition on the inner surfaces of the plasma air purifier occured. Our interpretation is that putative “degradation” efficiencies were largely due to electrostatic precipitation rather than to decomposition into smaller molecules.

In vitro production of buffalo embryos from stepwise vitrified immature oocytes.

Science.gov (United States)

Abd-Allah, Saber Mohammed

2009-01-01

This study was conducted to produce buffalo embryos in vitro from stepwise vitrified immature oocytes. Cumulus oocyte complexes (COCs) were obtained from the ovaries of slaughtered buffalo and were collected from the local abattoir. Selected COCs were exposed to a vitrification solution consisting of 40% ethylene glycol (EG) plus 0.3 M trehalose and 20% polyvinyl pyrrolidone (PVP) for 1 min and loaded in 0.25 ml plastic mini-straws containing 100 microl of 10% sucrose. The loaded cryostraws were cryopreserved by stepwise vitrification and were stored in liquid nitrogen for 4 to 6 months. Data analysis revealed a high percentage of post-thawing morphologically normal immature oocytes (80.7%) with a low percentage of damaged oocytes. There were no significant differences in the maturation (82.1%), cleavage (47.6%) and buffalo embryo development (15.4%) produced by the stepwise vitrified immature oocytes in comparison to the three observations in fresh oocytes (88.3%, 50.4% and 19.4%, respectively, p<0.05).

In vitro production of buffalo embryos from stepwise vitrified immature oocytes

Directory of Open Access Journals (Sweden)

Saber Mohammed Abd-Allah

2009-09-01

Full Text Available This study was conducted to produce buffalo embryos in vitro from stepwise vitrified immature oocytes. Cumulus oocyte complexes (COCs were obtained from the ovaries of slaughtered buffalo and were collected from the local abattoir. Selected COCs were exposed to a vitrification solution consisting of 40% ethylene glycol (EG plus 0.3 M trehalose and 20% polyvinyl pyrrolidone (PVP for 1 min and loaded in 0.25 ml plastic mini-straws containing 100 µl of 10% sucrose. The loaded cryostraws were cryopreserved by stepwise vitrification and were stored in liquid nitrogen for 4 to 6 months. Data analysis revealed a high percentage of post-thawing morphologically normal immature oocytes (80.7% with a low percentage of damaged oocytes. There were no significant differences in the maturation (82.1%, cleavage (47.6% and buffalo embryo development (15.4% produced by the stepwise vitrified immature oocytes in comparison to the three observations in fresh oocytes (88.3%, 50.4% and 19.4%, respectively, p<0.05.

Surface storage of vitrified high-level radioactive waste in reinforced-concrete casks

International Nuclear Information System (INIS)

Beale, H.; George, M.W.; Robertson, T.J.M.

1982-06-01

The feasibility of storing canisters containing vitrified high level radioactive waste in reinforced concrete casks is examined. This preliminary study identifies the limitations and probable cost of such a store and leads to the conclusion that the concept is feasible. (author)

Generation of low-temperature air plasma for food processing

Science.gov (United States)

Stepanova, Olga; Demidova, Maria; Astafiev, Alexander; Pinchuk, Mikhail; Balkir, Pinar; Turantas, Fulya

2015-11-01

The project is aimed at developing a physical and technical foundation of generating plasma with low gas temperature at atmospheric pressure for food industry needs. As known, plasma has an antimicrobial effect on the numerous types of microorganisms, including those that cause food spoilage. In this work an original experimental setup has been developed for the treatment of different foods. It is based on initiating corona or dielectric-barrier discharge in a chamber filled with ambient air in combination with a certain helium admixture. The experimental setup provides various conditions of discharge generation (including discharge gap geometry, supply voltage, velocity of gas flow, content of helium admixture in air and working pressure) and allows for the measurement of the electrical discharge parameters. Some recommendations on choosing optimal conditions of discharge generation for experiments on plasma food processing are developed.

Using depleted uranium to shield vitrified high-level waste packages

International Nuclear Information System (INIS)

Yoshimura, H.R.; Gildea, P.D.; Bernard, E.A.

1995-01-01

The underlying report for this paper evaluates options for using depleted uranium as shielding materials for transport systems for disposal of vitrified high-level waste (VHLW). In addition, economic analyses are presented to compare costs associated with these options to costs, associated with existing and proposed storage, transport, and diposal capabilities. A more detailed evaluation is provided elsewhere. (Yoshimura et al. 1995.)

CHARACTERIZATION OF VITRIFIED SAVANNAH RIVER SITE SB4 WASTE SURROGATE PRODUCED IN COLD CRUCIBLE

International Nuclear Information System (INIS)

Marra, J

2008-01-01

Savannah River Site (SRS) sludge batch 4 (SB4) waste surrogate with high aluminum and iron content was vitrified with commercially available Frit 503-R4 (8 wt.% Li 2 O, 16 wt.% B2O3, 76 wt.% SiO 2 ) by cold crucible inductive melting using lab- (56 mm inner diameter), bench- (236 mm) and large-scale (418 mm) cold crucible. The waste loading ranged between 40 and 60 wt.%. The vitrified products obtained in the lab-scale cold crucible were nearly amorphous with traces of unreacted quartz in the product with 40 wt.% waste loading and traces of spinel phase in the product with 50 wt.% waste loading. The glassy products obtained in the bench-scale cold crucible are composed of major vitreous and minor iron-rich spinel phase whose content at ∼60 wt.% waste loading may achieve ∼10 vol.%. The vitrified waste obtained in the large-scale cold crucible was also composed of major vitreous and minor spinel structure phases. No nepheline phase has been found. Average degree of crystallinity was estimated to be ∼12 vol.%. Anionic motif of the glass network is built from rather short metasilicate chains and boron-oxygen constituent based on boron-oxygen triangular units

Air spark-like plasma source for antimicrobial NOx generation

International Nuclear Information System (INIS)

Pavlovich, M J; Galleher, C; Curtis, B; Clark, D S; Graves, D B; Ono, T; Machala, Z

2014-01-01

We demonstrate and analyse the generation of nitrogen oxides and their antimicrobial efficacy using atmospheric air spark-like plasmas. Spark-like discharges in air in a 1 L confined volume are shown to generate NO x at an initial rate of about 1.5  ×  10 16 NO x molecules/J dissipated in the plasma. Such a discharge operating in this confined volume generates on the order of 6000 ppm NO x in 10 min. Around 90% of the NO x is in the form of NO 2 after several minutes of operation in the confined volume, suggesting that NO 2 is the dominant antimicrobial component. The strong antimicrobial action of the NO x mixture after several minutes of plasma operation is demonstrated by measuring rates of E. coli disinfection on surfaces and in water exposed to the NO x mixture. Some possible applications of plasma generation of NO x (perhaps followed by dissolution in water) include disinfection of surfaces, skin or wound antisepsis, and sterilization of medical instruments at or near room temperature. (paper)

Metabolic changes in droplet vitrified semen of wild endangered Persian sturgeon Acipenser persicus (Borodin, 1997).

Science.gov (United States)

Abed-Elmdoust, Amirreza; Farahmand, Hamid; Mojazi-Amiri, Bagher; Rafiee, Gholamreza; Rahimi, Ruhollah

2017-06-01

Comparative quantitative metabolite profiling can be used for better understanding of cell functions and dysfunctions in particular circumstances such as sperm banking which is an important approach for cryopreservation of endangered species. Cryopreservation techniques have some deleterious effects on spermatozoa which put the obtained results in controversy. Therefore, in the present study, quantitative 1 H NMR (Nuclear Magnetic Resonance) based metabolite profiling was conducted to evaluate metabolite changes related to energetics and some other detected metabolites in vitrified semen of critically endangered wild Acipenser persicus. The semen was diluted with extenders containing 0, 5, 10, and 15 μM of fish antifreeze protein (AFP) type III as a cryoprotectant. Semen-extenders were vitrified and stored for two days. Based on post-thaw motility duration and motility percentage assessments, two treatments with 10 μM and 0 μM of AFP had the highest and the lowest motility percentages respectively and they were objected to 1 H NMR spectroscopy investigations in order to reveal the extremes of the metabolites dynamic range. Univariate (ANOVA) and multivariate (PCA) analysis of the resulting metabolic profiles indicated significant changes (P > 0.05) in metabolites. The level of some metabolites including acetate, adenine, creatine, creatine phosphate, lactate, betaine, sarcosine, β-alanine and trimethylamine N-oxide significantly decreased in vitrified semen while some others such as creatinine, guanidinoacetate, N, N-dimethylglycine, and glycine significantly increased. There were also significant differences between vitrified treatments in levels of creatine, creatine phosphate, creatinine, glucose, guanidinoacetate, lactate, N, N-dimethylglycine, and glycine, suggesting how fish AFP type III can be effective as a cryoprotectant. Copyright © 2017 Elsevier Inc. All rights reserved.

PLUTONIUM/HIGH-LEVEL VITRIFIED WASTE BDBE DOSE CALCULATION

Energy Technology Data Exchange (ETDEWEB)

J.A. Ziegler

2000-11-20

The purpose of this calculation is to provide a dose consequence analysis of high-level waste (HLW) consisting of plutonium immobilized in vitrified HLW to be handled at the proposed Monitored Geologic Repository at Yucca Mountain for a beyond design basis event (BDBE) under expected conditions using best estimate values for each calculation parameter. In addition to the dose calculation, a plutonium respirable particle size for dose calculation use is derived. The current concept for this waste form is plutonium disks enclosed in cans immobilized in canisters of vitrified HLW (i.e., glass). The plutonium inventory at risk used for this calculation is selected from Plutonium Immobilization Project Input for Yucca Mountain Total Systems Performance Assessment (Shaw 1999). The BDBE examined in this calculation is a nonmechanistic initiating event and the sequence of events that follow to cause a radiological release. This analysis will provide the radiological releases and dose consequences for a postulated BDBE. Results may be considered in other analyses to determine or modify the safety classification and quality assurance level of repository structures, systems, and components. This calculation uses best available technical information because the BDBE frequency is very low (i.e., less than 1.0E-6 events/year) and is not required for License Application for the Monitored Geologic Repository. The results of this calculation will not be used as part of a licensing or design basis.

Clinical outcome of fresh and vitrified-warmed blastocyst and cleavage-stage embryo transfers in ethnic Chinese ART patients

Directory of Open Access Journals (Sweden)

Tong Guo

2012-10-01

Full Text Available Abstract Objectives This study sought to evaluate the outcome of fresh and vitrified-warmed cleavage-stage and blastocyst-stage embryo transfers in patients undergoing ART treatment within an ethnic Chinese population. Study design We compared the clinical results of embryo transfer on the 3rd (cleavage stage or 5th (blastocyst stage day after oocyte retrieval, including clinical pregnancy rates, implantation rates and multiple pregnancy rates. Results Our data showed that blastocyst transfer on day 5 did not significantly increase clinical pregnancy rate (41.07% vs 47.08%, p>0.05 and implantation rate (31.8% vs 31.2%, p>0.05 in patients under 35 years of age, in comparison with day 3 cleavage stage embryo transfer. In patients older than 35 years of age, the clinical pregnancy rate after blastocyst transfer was slightly decreased compared with cleavage stage embryo transfer (33.33% vs 42.31%, p>0.05. Unexpectedly, It was found that vitrified-warmed blastocyst transfer resulted in significantly higher clinical pregnancy rate (56.8% and implantation rate (47% compared with fresh blastocyst transfer in controlled stimulation cycles (41.07% and 31.8%, respectively. For patients under 35 years of age, the cumulative clinical pregnancy rate combining fresh and vitrified-warmed blastocyst transfer cycles were significantly higher compared to just cleavage-stage embryo transfer (70.1% versus 51.8%, p Conclusions In an ethnic Chinese patient population, fresh blastocyst transfer does not significantly increase clinical pregnancy rate. However, subsequent vitrified-warmed blastocyst transfer in a non-controlled ovarian hyperstimulation cycle dramatically improves clinical outcomes. Therefore, blastocyst culture in tandem with vitrified-warmed blastocyst transfer is recommended as a favourable and promising protocol in human ART treatment, particularly for ethnic Chinese patients.

Clinical outcome of fresh and vitrified-warmed blastocyst and cleavage-stage embryo transfers in ethnic Chinese ART patients.

Science.gov (United States)

Tong, Guo Qing; Cao, Shan Ren; Wu, Xun; Zhang, Jun Qiang; Cui, Ji; Heng, Boon Chin; Ling, Xiu Feng

2012-10-05

This study sought to evaluate the outcome of fresh and vitrified-warmed cleavage-stage and blastocyst-stage embryo transfers in patients undergoing ART treatment within an ethnic Chinese population. We compared the clinical results of embryo transfer on the 3rd (cleavage stage) or 5th (blastocyst stage) day after oocyte retrieval, including clinical pregnancy rates, implantation rates and multiple pregnancy rates. Our data showed that blastocyst transfer on day 5 did not significantly increase clinical pregnancy rate (41.07% vs 47.08%, p>0.05) and implantation rate (31.8% vs 31.2%, p>0.05) in patients under 35 years of age, in comparison with day 3 cleavage stage embryo transfer. In patients older than 35 years of age, the clinical pregnancy rate after blastocyst transfer was slightly decreased compared with cleavage stage embryo transfer (33.33% vs 42.31%, p>0.05). Unexpectedly, It was found that vitrified-warmed blastocyst transfer resulted in significantly higher clinical pregnancy rate (56.8%) and implantation rate (47%) compared with fresh blastocyst transfer in controlled stimulation cycles (41.07% and 31.8%, respectively). For patients under 35 years of age, the cumulative clinical pregnancy rate combining fresh and vitrified-warmed blastocyst transfer cycles were significantly higher compared to just cleavage-stage embryo transfer (70.1% versus 51.8%, p<0.05). However, the cumulative multiple pregnancy rates showed no significant difference between the two groups. In an ethnic Chinese patient population, fresh blastocyst transfer does not significantly increase clinical pregnancy rate. However, subsequent vitrified-warmed blastocyst transfer in a non-controlled ovarian hyperstimulation cycle dramatically improves clinical outcomes. Therefore, blastocyst culture in tandem with vitrified-warmed blastocyst transfer is recommended as a favourable and promising protocol in human ART treatment, particularly for ethnic Chinese patients.

Lessons learned in demonstration projects regarding operational safety during final disposal of vitrified waste and spent fuel

International Nuclear Information System (INIS)

Filbert, Wolfgang; Herold, Philipp

2015-01-01

The paper summarizes the lessons learned in demonstration projects regarding operational safety during the final disposal of vitrified waste and spent fuel. The three demonstration projects for the direct disposal of vitrified waste and spent fuel are described. The first two demonstration projects concern the shaft transport of heavy payloads of up to 85 t and the emplacement operations in the mine. The third demonstration project concerns the borehole emplacement operation. Finally, open issues for the next steps up to licensing of the emplacement and disposal systems are summarized.

Control of multidrug-resistant planktonic Acinetobacter baumannii: biocidal efficacy study by atmospheric-pressure air plasma

Science.gov (United States)

Zhe, RUAN; Yajun, GUO; Jing, GAO; Chunjun, YANG; Yan, LAN; Jie, SHEN; Zimu, XU; Cheng, CHENG; Xinghao, LIU; Shumei, ZHANG; Wenhui, DU; Paul, K. CHU

2018-04-01

In this research, an atmospheric-pressure air plasma is used to inactivate the multidrug-resistant Acinetobacter baumannii in liquid. The efficacy of the air plasma on bacterial deactivation and the cytobiological variations after the plasma treatment are investigated. According to colony forming units, nearly all the bacteria (6-log) are inactivated after 10 min of air plasma treatment. However, 7% of the bacteria enter a viable but non-culturable state detected by the resazurin based assay during the same period of plasma exposure. Meanwhile, 86% of the bacteria lose their membrane integrity in the light of SYTO 9/PI staining assay. The morphological changes in the cells are examined by scanning electron microscopy and bacteria with morphological changes are rare after plasma exposure in the liquid. The concentrations of the long-living RS, such as H2O2, {{{{NO}}}3}-, and O3, in liquid induced by plasma treatment are measured, and they increase with plasma treatment time. The changes of the intracellular ROS may be related to cell death, which may be attributed to oxidative stress and other damage effects induced by RS plasma generated in liquid. The rapid and effective bacteria inactivation may stem from the RS in the liquid generated by plasma and air plasmas may become a valuable therapy in the treatment of infected wounds.

Study on improvement in reliability of inventory assessment in vitrified waste for long-term safety of geological disposal

International Nuclear Information System (INIS)

Ishikawa, Masumi; Kaneko, Satoru; Kitayama, Kazumi; Ishiguro, Katsuhiko; Ueda, Hiroyoshi; Wakasugi, Keiichiro; Shinohara, Nobuo; Okumura, Keisuke; Chino, Masamichi; Moriya, Noriyasu

2009-01-01

Since quality control issues for vitrified waste are defined mainly with the focus on the transport and interim storage of the waste rather than the long-term safety of geological disposal, they do not cover inventories of long-lived nuclides that are of most interest in the safety assessment of geological disposal. Therefore, we suggest a flow chart for the assessment of inventories of long-lived nuclides in the vitrified waste focusing on the measured values. This includes an indirect assessment with indicative nuclides that have been already measured in the returned vitrified wastes from abroad. In order to apply this flow chart for commercial operation, its applicability should be examined for cases with a variation in burn-up history and with an uncertainty associated with carry-over fraction at reprocessing. We started an R and D program to examine the applicability as well as to improve the reliability of the nuclide generation/decay code and the nuclear data library using liquid waste from spent fuel with a clear irradiation history. To solve the issue of quality control for vitrified waste, a comprehensive study is needed in aspects not only of geological disposal field but also of operation of a nuclear power plant, reprocessing of spent fuel and vitrification of liquid waste. This study is a pioneering study conducted to integrate them. (author)

Direct current plasma jet at atmospheric pressure operating in nitrogen and air

Science.gov (United States)

Deng, X. L.; Nikiforov, A. Yu.; Vanraes, P.; Leys, Ch.

2013-01-01

An atmospheric pressure direct current (DC) plasma jet is investigated in N2 and dry air in terms of plasma properties and generation of active species in the active zone and the afterglow. The influence of working gases and the discharge current on plasma parameters and afterglow properties are studied. The electrical diagnostics show that discharge can be sustained in two different operating modes, depending on the current range: a self-pulsing regime at low current and a glow regime at high current. The gas temperature and the N2 vibrational temperature in the active zone of the jet and in the afterglow are determined by means of emission spectroscopy, based on fitting spectra of N2 second positive system (C3Π-B3Π) and the Boltzmann plot method, respectively. The spectra and temperature differences between the N2 and the air plasma jet are presented and analyzed. Space-resolved ozone and nitric oxide density measurements are carried out in the afterglow of the jet. The density of ozone, which is formed in the afterglow of nitrogen plasma jet, is quantitatively detected by an ozone monitor. The density of nitric oxide, which is generated only in the air plasma jet, is determined by means of mass-spectroscopy techniques.

Spectrally resolved measurements of the terahertz beam profile generated from a two-color air plasma

DEFF Research Database (Denmark)

Pedersen, Pernille Klarskov; Zalkovskij, Maksim; Strikwerda, Andrew

2014-01-01

Using a THz camera and THz bandpass filters, we measure the frequency - resolved beam profile emitted from a two - color air plasma. We observe a frequency - independent emission angle from the plasma .......Using a THz camera and THz bandpass filters, we measure the frequency - resolved beam profile emitted from a two - color air plasma. We observe a frequency - independent emission angle from the plasma ....

Tomographic Measurements of Temperature Fluctuations in an Air Plasma Cutting Torch

Czech Academy of Sciences Publication Activity Database

Hlína, Jan; Šonský, Jiří; Gruber, Jan

2017-01-01

Roč. 37, č. 3 (2017), s. 689-699 ISSN 0272-4324 Institutional support: RVO:61388998 Keywords : cutting arc * air plasma * tomography Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.355, year: 2016 http://link.springer.com/ article /10.1007%2Fs11090-017-9794-x

Fast tomographic measurements of temperature in an air plasma cutting torch

Czech Academy of Sciences Publication Activity Database

Hlína, Jan; Šonský, Jiří; Gruber, Jan; Cressault, Y.

2016-01-01

Roč. 49, č. 10 (2016), č. článku 105202. ISSN 0022-3727 Institutional support: RVO:61388998 Keywords : air plasma * cutting torch * tomography Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.588, year: 2016

NDA issues with RFETS vitrified waste forms

International Nuclear Information System (INIS)

Hurd, J.; Veazey, G.

1998-01-01

A study was conducted at Los Alamos National Laboratory (LANL) for the purpose of determining the feasibility of using a segmented gamma scanner (SGS) to accurately perform non-destructive analysis (NDA) on certain Rocky Flats Environmental Technology Site (RFETS) vitrified waste samples. This study was performed on a full-scale vitrified ash sample prepared at LANL according to a procedure similar to that anticipated to be used at RFETS. This sample was composed of a borosilicate-based glass frit, blended with ash to produce a Pu content of ∼1 wt %. The glass frit was taken to a degree of melting necessary to achieve a full encapsulation of the ash material. The NDA study performed on this sample showed that SGSs with either 1/2- or 2-inch collimation can achieve an accuracy better than 6 % relative to calorimetry and γ-ray isotopics. This accuracy is achievable, after application of appropriate bias corrections, for transmissions of about 1/2 % through the waste form and counting times of less than 30 minutes. These results are valid for ash material and graphite fines with the same degree of plutonium particle size, homogeneity, sample density, and sample geometry as the waste form used to obtain the results in this study. A drum-sized thermal neutron counter (TNC) was also included in the study to provide an alternative in the event the SGS failed to meet the required level of accuracy. The preliminary indications are that this method will also achieve the required accuracy with counting times of ∼30 minutes and appropriate application of bias corrections. The bias corrections can be avoided in all cases if the instruments are calibrated on standards matching the items

Effects of atmospheric air plasma treatment on interfacial properties of PBO fiber reinforced composites

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chengshuang, E-mail: cszhang83@163.com; Li, Cuiyun; Wang, Baiya; Wang, Bin; Cui, Hong

2013-07-01

Poly(p-phenylene benzobisoxazole) (PBO) fiber was modified by atmospheric air plasma treatment. The effects of plasma treatment power and speed on both surface properties of PBO fibers and interfacial properties of PBO/epoxy composites were investigated. Surface chemical composition of PBO fibers were analyzed by X-ray photoelectron spectroscopy (XPS). Surface morphologies of the fibers and interface structures of the composites were examined using scanning electron microscopy (SEM). Interfacial adhesion property of the composites was evaluated by interlaminar shear strength (ILSS). Mechanical properties of PBO multifilament were measured by universal testing machine. The results indicate that atmospheric air plasma treatment introduced some polar or oxygen-containing groups to PBO fiber surfaces, enhanced surface roughness and changed surface morphologies of PBO fibers by plasma etching and oxidative reactions. The plasma treatment also improved interfacial adhesion of PBO/epoxy composites but has little effect on tensile properties of PBO multifilament. The ILSS of PBO/epoxy composites increased to 40.0 MPa after atmospheric air plasma treatment with plasma treatment power of 300 W and treatment speed of 6 m/min.

Local geology controlled the feasibility of vitrifying Iron Age buildings.

Science.gov (United States)

Wadsworth, Fabian B; Heap, Michael J; Damby, David E; Hess, Kai-Uwe; Najorka, Jens; Vasseur, Jérémie; Fahrner, Dominik; Dingwell, Donald B

2017-01-12

During European prehistory, hilltop enclosures made from polydisperse particle-and-block stone walling were exposed to temperatures sufficient to partially melt the constituent stonework, leading to the preservation of glassy walls called 'vitrified forts'. During vitrification, the granular wall rocks partially melt, sinter viscously and densify, reducing inter-particle porosity. This process is strongly dependent on the solidus temperature, the particle sizes, the temperature-dependence of the viscosity of the evolving liquid phase, as well as the distribution and longevity of heat. Examination of the sintering behaviour of 45 European examples reveals that it is the raw building material that governs the vitrification efficiency. As Iron Age forts were commonly constructed from local stone, we conclude that local geology directly influenced the degree to which buildings were vitrified in the Iron Age. Additionally, we find that vitrification is accompanied by a bulk material strengthening of the aggregates of small sizes, and a partial weakening of larger blocks. We discuss these findings in the context of the debate surrounding the motive of the wall-builders. We conclude that if wall stability by bulk strengthening was the desired effect, then vitrification represents an Iron Age technology that failed to be effective in regions of refractory local geology.

Experimental study of the behavior of two laser produced plasmas in air

Energy Technology Data Exchange (ETDEWEB)

Yang, Zefeng; Wei, Wenfu; Han, Jiaxun; Wu, Jian, E-mail: jxjawj@gmail.com; Li, Xingwen; Jia, Shenli [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Shaanxi 710049 (China)

2015-07-15

The interactions among two laser ablated Al plasmas and their shock wave fronts (SWFs) induced by double laser pulses in air were studied experimentally. The evolution processes, including the expansion and interaction of the two plasmas and their shocks, were investigated by laser shadowgraphs, schlieren images, and interferograms. Remarkably, the distribution of the compressed air and the laser plasmas during the colliding process was clearly obtained using the Mach-Zehnder interferometer. From the refractive index profiles, typical plasmas density and gas density behind the shock front were estimated as ∼5.2 × 10{sup 18 }cm{sup −3} and ∼2.4 × 10{sup 20 }cm{sup −3}. A stagnation layer formed by the collision of gas behind the shock front is observed. The SWFs propagated, collided, and reflected with a higher velocity than plasmas. The results indicated that the slower plasma collided at middle, leading to the formation of the soft stagnation.

Air core poloidal magnetic field system for a toroidal plasma producing device

International Nuclear Information System (INIS)

Marcus, F.B.

1978-01-01

A poloidal magnetics system for a plasma producing device of toroidal configuration is provided that reduces both the total volt-seconds requirement and the magnitude of the field change at the toroidal field coils. The system utilizes an air core transformer wound between the toroidal field (TF) coils and the major axis outside the TF coils. Electric current in the primary windings of this transformer is distributed and the magnetic flux returned by air core windings wrapped outside the toroidal field coils. A shield winding that is closely coupled to the plasma carries a current equal and opposite to the plasma current. This winding provides the shielding function and in addition serves in a fashion similar to a driven conducting shell to provide the equilibrium vertical field for the plasma. The shield winding is in series with a power supply and a decoupling coil located outside the TF coil at the primary winding locations. The present invention requires much less energy than the usual air core transformer and is capable of substantially shielding the toroidal field coils from poloidal field flux

Properties of vitrified rocky flats TRUW with different waste loadings

International Nuclear Information System (INIS)

Eddy, T.L.; Sears, J.W.; Grandy, J.D.; Miley, D.V.; Erickson, A.W.; Farnsworth, R.N.; Larsen, E.D.

1994-01-01

Leach rates, phase structures, and mechanical properties of simulated Rocky Flats Plant 1st and 2nd slate sludge vitrified in an arc melter are described as a function of waste to soil fraction and method of devitrification to produce the glass-ceramic waste form. Volatile, hazardous, and transuranic (TRU) surrogate metals were added to assess dissolution effects. Zirconia and titania were also added to confirm their ability as transuranic-surrogate getters

Efficient production of live offspring from mouse oocytes vitrified with a novel cryoprotective agent, carboxylated ε-poly-L-lysine.

Directory of Open Access Journals (Sweden)

Hitomi Watanabe

Full Text Available In cryopreservation of mammalian germ cells, unfertilized oocytes are one of the most available stages because these cryopreserved oocytes can be used for assisted reproductive technologies, including in vitro fertilization (IVF and intracytoplasmic sperm injection. However, it has been generally reported that the fertility and developmental ability of the oocytes are reduced by cryopreservation. Therefore further improvement will be required. Very recently, a new cryoprotective agent (CPA, called as carboxylated ε-poly-L-lysine (COOH-PLL, has been developed to reduce physical and physiological damage by cryopreservation in mammalian stem cells. However, it is unclear the effect of COOH-PLL on fertility and developmental ability of vitrified oocytes. In this study, we used COOH-PLL as a CPA with ethylene glycol (EG for vitrification of mouse oocytes. Cumulus-oocyte complexes (COCs were collected from ICR mice and then vitrified with Cryotop using different concentration of COOH-PLL and EG. A combined treatment with COOH-PLL and EG showed high survival rate (more than 90% of vitrified-warmed COCs after in vitro fertilization. In addition, the fertility and developmental ability of COCs vitrified with E20P10 [EG 20% (v/v and COOH-PLL 10% (w/v] or E15P15 group (EG 15% and COOH-PLL 15% were significantly higher than those with E10P20 (EG10% and COOH-PLL 20% or P30 group (PLL30%. The vitrified COCs in E20P10 group developed to term at a high success rate (46.2% and it was significantly higher than that in control (E30 group (34.8%. Our present study demonstrated for the first time that COOH-PLL is effective for vitrification of mouse oocytes.

Modeling of thermal plasma arc technology FY 1994 report

International Nuclear Information System (INIS)

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

1995-03-01

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

Fine Structure of a Laser-Plasma Filament in Air

International Nuclear Information System (INIS)

Eisenmann, Shmuel; Pukhov, Anatoly; Zigler, Arie

2007-01-01

The ability to select and stabilize a single filament during propagation of an ultrashort high-intensity laser pulse in air makes it possible to examine the longitudinal structure of the plasma channel left in its wake. We present detailed measurements of plasma density variations along laser propagation. Over the length of the filament, electron density variations of 3 orders of magnitude are measured. They display evidence of a meter-long postionization range, along which a self-guided structure is observed coupled with a low plasma density, corresponding to ∼3 orders of magnitude decrease from the peak density level

Fine Structure of a Laser-Plasma Filament in Air

Science.gov (United States)

Eisenmann, Shmuel; Pukhov, Anatoly; Zigler, Arie

2007-04-01

The ability to select and stabilize a single filament during propagation of an ultrashort high-intensity laser pulse in air makes it possible to examine the longitudinal structure of the plasma channel left in its wake. We present detailed measurements of plasma density variations along laser propagation. Over the length of the filament, electron density variations of 3 orders of magnitude are measured. They display evidence of a meter-long postionization range, along which a self-guided structure is observed coupled with a low plasma density, corresponding to ˜3 orders of magnitude decrease from the peak density level.

Laser-induced plasmas in air studied using two-color interferometry

International Nuclear Information System (INIS)

Yang, Zefeng; Wu, Jian; Li, Xingwen; Han, Jiaxun; Jia, Shenli; Qiu, Aici; Wei, Wenfu

2016-01-01

Temporally and spatially resolved density profiles of Cu atoms, electrons, and compressed air, from laser-induced copper plasmas in air, are measured using fast spectral imaging and two-color interferometry. From the intensified CCD images filtered by a narrow-band-pass filter centered at 515.32 nm, the Cu atoms expansion route is estimated and used to determine the position of the fracture surface between the Cu atoms and the air. Results indicate that the Cu atoms density at distances closer to the target (0–0.4 mm) is quite low, with the maximum density appearing at the edge of the plasma's core being ∼4.6 × 10"2"4" m"−"3 at 304 ns. The free electrons are mainly located in the internal region of the plume, which is supposed to have a higher temperature. The density of the shock wave is (4–6) × 10"2"5" m"−"3, corresponding to air compression of a factor of 1.7–2.5.

Laser-induced plasmas in air studied using two-color interferometry

Energy Technology Data Exchange (ETDEWEB)

Yang, Zefeng; Wu, Jian, E-mail: jxjawj@mail.xjtu.edu.cn; Li, Xingwen; Han, Jiaxun; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Shaanxi 710049 (China); Wei, Wenfu [School of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

2016-08-15

Temporally and spatially resolved density profiles of Cu atoms, electrons, and compressed air, from laser-induced copper plasmas in air, are measured using fast spectral imaging and two-color interferometry. From the intensified CCD images filtered by a narrow-band-pass filter centered at 515.32 nm, the Cu atoms expansion route is estimated and used to determine the position of the fracture surface between the Cu atoms and the air. Results indicate that the Cu atoms density at distances closer to the target (0–0.4 mm) is quite low, with the maximum density appearing at the edge of the plasma's core being ∼4.6 × 10{sup 24 }m{sup −3} at 304 ns. The free electrons are mainly located in the internal region of the plume, which is supposed to have a higher temperature. The density of the shock wave is (4–6) × 10{sup 25 }m{sup −3}, corresponding to air compression of a factor of 1.7–2.5.

Theoretical-experimental comparison of vitrified glass container behavior using the Castem system

International Nuclear Information System (INIS)

Moncouyoux, J.P.; Jamet, P.; Combescure, A.; Millard, A.

1989-01-01

This paper compares theoretical predictions of vitrified nuclear waste glass package collapse with experimental values in order to qualify the mathematical models describing canister deformation under external pressure loads. After briefly outlining the program and describing the experiments performed, the paper discusses the theoretical predictions based on the INCA code from the CEA's CASTEM system

Oyster Shell Recycling and Bone Waste Treatment Using Plasma Pyrolysis

International Nuclear Information System (INIS)

Chae, Jae Ou; Knak, S P; Knak, A N; Koo, H J; Ravi, V

2006-01-01

Investigations on the recycling of oyster shells and bone waste treatment using the plasma pyrolysis technique are presented in this paper. A arc based plasma torch operated at 25 kW was employed for the experiments. Fresh oyster shells were recycled using the plasma torch to convert them to a useful product such as CaO. Bone waste was treated to remove the infectious organic part and to vitrify the inorganic part. The time required for treatment in both cases was significantly short. Significant reduction in the weight of the samples was observed in both cases

Oyster Shell Recycling and Bone Waste Treatment Using Plasma Pyrolysis

Science.gov (United States)

Jae, Ou Chae; Knak, S. P.; Knak, A. N.; Koo, H. J.; Ravi, V.

2006-11-01

Investigations on the recycling of oyster shells and bone waste treatment using the plasma pyrolysis technique are presented in this paper. A arc based plasma torch operated at 25 kW was employed for the experiments. Fresh oyster shells were recycled using the plasma torch to convert them to a useful product such as CaO. Bone waste was treated to remove the infectious organic part and to vitrify the inorganic part. The time required for treatment in both cases was significantly short. Significant reduction in the weight of the samples was observed in both cases.

Destruction of inorganic municipal solid waste incinerator fly ash in a DC arc plasma furnace.

Science.gov (United States)

Zhao, Peng; Ni, Guohua; Jiang, Yiman; Chen, Longwei; Chen, Mingzhou; Meng, Yuedong

2010-09-15

Due to the toxicity of dioxins, furans and heavy metals, there is a growing environmental concern on municipal solid waste incinerator (MSWI) fly ash in China. The purpose of this study is directed towards the volume-reduction of fly ash without any additive by thermal plasma and recycling of vitrified slag. This process uses extremely high-temperature in an oxygen-starved environment to completely decompose complex waste into very simple molecules. For developing the proper plasma processes to treat MSWI fly ash, a new crucible-type plasma furnace was built. The melting process metamorphosed fly ash to granulated slag that was less than 1/3 of the volume of the fly ash, and about 64% of the weight of the fly ash. The safety of the vitrified slag was tested. The properties of the slag were affected by the differences in the cooling methods. Water-cooled and composite-cooled slag showed more excellent resistance against the leaching of heavy metals and can be utilized as building material without toxicity problems. Copyright 2010 Elsevier B.V. All rights reserved.

Organizing a complex transport while guaranteeing safety and transparency: the example of vitrified wastes sent back to Germany

International Nuclear Information System (INIS)

Krochmaluk, Julie; Lebrun, Marc; Delmestre, Alain; Barbey, Pierre; Bonvalot, Vanessa; Belleville, Didier; Rollinger, Patrice; Alter, Ulrich

2012-01-01

This chapter is made of several small articles entitled: - 'Les controles avant le depart du convoi franco-allemand' (Controls before the departure of the French-German convoy); - 'La supervision des transports de matieres radioactives: une approche extensive de la surete des operations' (The supervision of radioactive material transports: an extended approach of operation safety); - 'Le dispositif d'information du public sur le transport des substances radioactives mis en place par l'ASN' (The plan implemented by the ASN for public information on nuclear materials transport); - 'Le recours de l'ASN a l'expertise de l'ACRO sur le convoi de colis de dechets vitrifies vers l'Allemagne' (The appeal of the ASN to the ACRO's expertise on the vitrified parcel convoy to Germany); - 'La participation du collectif STOP-EPR a l'inspection de l'ASN du convoi de colis de dechets vitrifies vers l'Allemagne' (The participation of the STOP-EPR collective to the control by the ASN of the vitrified parcel convoy to Germany); - 'La securite et la surete: des valeurs que le Groupe SNCF partage' (Security and safety: values which are shared by the SNCF Group); - 'Le transport de matieres nucleaires entre la France et l'Allemagne au cours des 40 dernieres annees' (Transport of nuclear materials between France and Germany during the last 40 years). Addressing the case of vitrified wastes transported back to Germany, the articles indicate the controls performed in France before convoy departure, discuss the approach adopted for the safety of radioactive material transport, comment the management of public information by the ASN for such transports, comment the intervention of the ACRO (Association for the control of radioactivity in western France) on the request of the ASN and the participation of a collective group (STOP-EPR) to the inspection of a convoy, outline the commitment of the French Railways (SNCF) in terms of security and safety, and give a qualitative and quantitative

Cryostorage duration does not affect pregnancy and neonatal outcomes: a retrospective single-centre cohort study of vitrified-warmed blastocysts.

Science.gov (United States)

Ueno, Satoshi; Uchiyama, Kazuo; Kuroda, Tomoko; Yabuuchi, Akiko; Ezoe, Kenji; Okimura, Tadashi; Okuno, Takashi; Kobayashi, Tamotsu; Kato, Keiichi

2018-06-01

A retrospective cohort study of 8736 autologous single vitrified-warmed blastocyst transfer cycles was conducted in a single centre to investigate the effect of cryostorage on clinical and neonatal outcomes. Cryostorage duration was classified into three groups: (A) 0-2 months (n = 4702); (B) 2-13 months (n = 2853) and (C) 13-97 months (n = 1181). Blastocysts were vitrified using the Cryotop method. No significant differences were observed in live birth rates: (A) 37.3%; (B) 34.9%; (C) (35.2%). Gestational period was significantly shorter in group C: (A) 38.7 ± 1.8; (B) 38.6 ± 1.6; (C) 38.1 ± 1.7; P limitation of this study was that maximum storage duration was 8 years; most blastocysts were in cryostorage for much shorter periods. Long-term storage of blastocysts that are vitrified using an open device vitrification system has no negative effect on pregnancy and neonatal outcomes. Copyright © 2018 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Geochemical and petrographic studies and the relationships to durability and leach resistance of vitrified products from the in situ vitrification process

International Nuclear Information System (INIS)

Timmons, D.M.; Thompson, L.E.

1996-01-01

Soil and sludge contaminated with hazardous and radioactive materials from sites in the United States and Australia were vitrified using in situ vitrification. Some of the resulting products were subjected to detailed geochemical, leach and durability testing using a variety of analytical techniques. The leach resistance and durability performance was compared to that of vitrified high level waste with borosilicate composition. Particular attention was given to crystallization behavior, the effects of crystallization on residual melt chemistry and how crystallization influences the behavior of contaminant ions. The results of this work show that the vitrified material studied has superior chemical durability and leach resistance relative to typical borosilicate waste glasses. Crystallization behavior was variable depending upon melt chemistry and cooling history. Crystallization was not observed to adversely affect chemical durability or leach resistance

Surface modification of polyester fabrics by atmospheric-pressure air/He plasma for color strength and adhesion enhancement

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chunming, E-mail: zcm1229@126.com [College of Textiles and Clothing, Qingdao University, Qingdao 266071 (China); Sunvim Grp Co Ltd, Gaomi 261500 (China); Zhao, Meihua; Wang, Libing; Qu, Lijun [College of Textiles and Clothing, Qingdao University, Qingdao 266071 (China); Men, Yajing [Sunvim Grp Co Ltd, Gaomi 261500 (China)

2017-04-01

Highlights: • Air/He plasma gave hydrophilicity on polyester surface and decreased contact angle to 18°. • The roughness of polyester increased and pit-like structures appeared on the surface after plasma treatment. • XPS confirmed the generation of new functional groups on polyester fabric. • The improved pigment color yield and anti-bleeding performance were contributed by the alteration of pigment adhesion. • The air/He plasma was more effective than air plasma at the same treatment time. - Abstract: Surface properties of water-based pigmented inks for ink-jet printed polyester fabrics were modified with atmospheric-pressure air/He plasma to improve the color strength and pigment adhesion of the treated surfaces. The influence of various parameters, including the surface morphology, chemical compositions, surface energy and dynamic contact angles of the control and plasma treated samples was studied. Color strength and edge definition were used to evaluate the ink-jet printing performance of fabrics. The change in pigment adhesion to polyester fibers was analyzed by SEM (scanning electron microscopy). AFM (Atomic force microscope) and XPS (X-ray photoelectron spectroscopy) analyses indicated the increase in surface roughness and the oxygen-containing polar groups(C=O, C−OH and COOH) reinforced the fixation of pigments on the fiber surface. The result from this study suggested that the improved pigment color yield was clearly affected by alteration of pigment adhesion enhanced by plasma surface modification. Polyester fabrics exhibited better surface property and ink-jet printing performance after the air/He mixture plasma treatment comparing with those after air plasma treatment.

Surface modification of polyester fabrics by atmospheric-pressure air/He plasma for color strength and adhesion enhancement

International Nuclear Information System (INIS)

Zhang, Chunming; Zhao, Meihua; Wang, Libing; Qu, Lijun; Men, Yajing

2017-01-01

Highlights: • Air/He plasma gave hydrophilicity on polyester surface and decreased contact angle to 18°. • The roughness of polyester increased and pit-like structures appeared on the surface after plasma treatment. • XPS confirmed the generation of new functional groups on polyester fabric. • The improved pigment color yield and anti-bleeding performance were contributed by the alteration of pigment adhesion. • The air/He plasma was more effective than air plasma at the same treatment time. - Abstract: Surface properties of water-based pigmented inks for ink-jet printed polyester fabrics were modified with atmospheric-pressure air/He plasma to improve the color strength and pigment adhesion of the treated surfaces. The influence of various parameters, including the surface morphology, chemical compositions, surface energy and dynamic contact angles of the control and plasma treated samples was studied. Color strength and edge definition were used to evaluate the ink-jet printing performance of fabrics. The change in pigment adhesion to polyester fibers was analyzed by SEM (scanning electron microscopy). AFM (Atomic force microscope) and XPS (X-ray photoelectron spectroscopy) analyses indicated the increase in surface roughness and the oxygen-containing polar groups(C=O, C−OH and COOH) reinforced the fixation of pigments on the fiber surface. The result from this study suggested that the improved pigment color yield was clearly affected by alteration of pigment adhesion enhanced by plasma surface modification. Polyester fabrics exhibited better surface property and ink-jet printing performance after the air/He mixture plasma treatment comparing with those after air plasma treatment.

Production and Characterization of Femtosecond-Laser-Induced Air Plasma

National Research Council Canada - National Science Library

Armbruster, David R

2008-01-01

.... A beam expander was used to expand the beam to a diameter of approximately 6.5 mm, and the beam was focused through a 25 mm focal length achromatic lens to produce laser-induced plasma in ambient air...

Technology survey for real-time monitoring of plutonium in a vitrifier off-gas system

International Nuclear Information System (INIS)

Berg, J.M.; Veirs, D.K.

1996-01-01

We surveyed several promising measurement technologies for the real-time monitoring of plutonium in a vitrifier off-gas system. The vitrifier is being developed by Westinghouse Savannah River Corp. and will be used to demonstrate vitrification of plutonium dissolved in nitric acid for fissile material disposition. The risk of developing a criticality hazard in the off-gas processing equipment can be managed by using available measurement technologies. We identified several potential technologies and methods for detecting plutonium that are sensitive enough to detect the accumulation of a mass sufficient to form a criticality hazard. We recommend gross alpha-monitoring technologies as the most promising option for Westinghouse Savannah River Corp. to consider because that option appears to require the least additional development. We also recommend further consideration for several other technologies because they offer specific advantages and because gross alpha-monitoring could prove unsuitable when tested for this specific application

Effect of composition variations on the long-term wasteform behavior of vitrified domestic waste incineration fly-ash purification residues

International Nuclear Information System (INIS)

Frugier, Pierre

1999-01-01

The effect of variations in the composition of fly-ash purification residue from incinerated domestic waste on the quality of the containment achieved by vitrification was investigated. Three main factors determine the long-term containment quality: the production of a vitrified wasteform, the occurrence of possible crystallization, and the key parameters of long-term alteration in aqueous media. Each of these aspects is described within a composition range defined by variations in the three major elements. (silicon, calcium and aluminum) and two groups of constituents (alkali metals and toxic elements). The silicon fraction in the fly-ash residue was found to be decisive: it is impossible to obtain a satisfactory vitrified wasteform below a given silicon concentration. Compounds with the lowest silica content also exhibited the greatest tendency to crystallize under the cooling conditions prevailing in industrial processes (the dominant crystallized phase is a melilite that occupies a significant fraction of the material and considerably modifies the alteration mechanisms). The initial alteration rate in pure water and the altered glass thickness measured in a closed system at an advanced stage of the dissolution reaction are both inversely related to the silicon concentration in the glass. Several types of long-term behavior were identified according to the composition range, the process conditions and the vitrified waste disposal scenario. Four distinct 'classes' of vitrified wasteform were defined for direct application in industrial processes. (author) [fr

Cold air plasma to decontaminate inanimate surfaces of the hospital environment.

Science.gov (United States)

Cahill, Orla J; Claro, Tânia; O'Connor, Niall; Cafolla, Anthony A; Stevens, Niall T; Daniels, Stephen; Humphreys, Hilary

2014-03-01

The hospital environment harbors bacteria that may cause health care-associated infections. Microorganisms, such as multiresistant bacteria, can spread around the patient's inanimate environment. Some recently introduced biodecontamination approaches in hospitals have significant limitations due to the toxic nature of the gases and the length of time required for aeration. This study evaluated the in vitro use of cold air plasma as an efficient alternative to traditional methods of biodecontamination of hospital surfaces. Cultures of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli, and Acinetobacter baumannii were applied to different materials similar to those found in the hospital environment. Artificially contaminated sections of marmoleum, mattress, polypropylene, powder-coated mild steel, and stainless steel were then exposed to a cold air pressure plasma single jet for 30 s, 60 s, and 90 s, operating at approximately 25 W and 12 liters/min flow rate. Direct plasma exposure successfully reduced the bacterial load by log 3 for MRSA, log 2.7 for VRE, log 2 for ESBL-producing E. coli, and log 1.7 for A. baumannii. The present report confirms the efficient antibacterial activity of a cold air plasma single-jet plume on nosocomial bacterially contaminated surfaces over a short period of time and highlights its potential for routine biodecontamination in the clinical environment.

Experimental Study on Indoor Air Cleaning Technique of Nano-Titania Catalysis Under Plasma Discharge

International Nuclear Information System (INIS)

Gao Deli; Yang Xuechang; Zhou Fei; Wu Yuhuang

2008-01-01

In this study, a new technique of air cleaning by plasma combined with catalyst was proposed, which consisted of electrostatic precipitation, volatile organic compounds (VOCs) decomposition and sterilization. A novel indoor air purifier based on this technique was adopted. The experimental results showed that formaldehyde decomposition by the plasma-catalyst hybrid system was more efficient than that by plasma only. Positive discharge was better than negative discharge in formaldehyde removal. Meanwhile, the outlet concentration of ozone byproduct was effectively reduced by the nano-titania catalyst.

Birth of normal infants after transfer of embryos that were twice vitrified/warmed at cleavage stages: report of two cases.

Science.gov (United States)

Valle, Marcello; Guimarães, Fernando; Cavagnoli, Melissa; Sampaio, Marcos; Geber, Selmo

2012-12-01

The role of cryopreservation in assisted reproductive technology programs has increased within the last years allowing the transfer of a limited number of embryos and the storage of the remaining for future use. The reduction in the number of transferred embryos decreases the frequency of multiple pregnancy rates and of ovarian hyperstimulation syndrome while the cumulative pregnancy rate can be maximized. Moreover, as not all embryos will survive the warming process more cleavage stage embryos are warmed to improve selection for transfer. Therefore, surplus good quality cleavage stage embryos and/or blastocysts must be re-vitrified for further transfer to achieve pregnancy. To our knowledge, there have been no reports demonstrating that human embryos can be successfully vitrified/warmed twice at the cleavage stage. Thus we report two successful pregnancies and deliveries of healthy babies after transfer of embryos that were twice vitrified/warmed at 2-4 cells stage. Copyright © 2012 Elsevier Inc. All rights reserved.

Vitrified medical wastes bottom ash in cement clinkerization. Microstructural, hydration and leaching characteristics.

Science.gov (United States)

Papamarkou, S; Christopoulos, D; Tsakiridis, P E; Bartzas, G; Tsakalakis, K

2018-04-19

The present investigation focuses on the utilization of medical wastes incineration bottom ash (MBA), vitrified with soda lime recycled glass (SLRG), as an alternative raw material in cement clinkerization. Bottom ash is recovered from the bottom of the medical wastes incineration chamber, after being cooled down through quenching. It corresponds to 10-15 wt% of the initial medical wastes weight and since it has been classified in the category of hazardous wastes, its safe management has become a major environmental concern worldwide. MBA glasses of various syntheses were initially obtained during the MBA vitrification simultaneously with various amounts of silica scrap (20, 25 and 30 wt% correspondingly). The produced MBA glasses were in turn used for the production of Portland cement clinker, after sintering at 1400 °C, thus substituting traditional raw materials. Both evaluation of vitrification and sintering products was carried out by chemical and mineralogical analyses along with microstructure examination. The final cements were prepared by clinkers co-grinding in a laboratory ball mill with appropriate amounts of gypsum (≈5.0 wt%) and the evaluation of their quality was carried out by determining setting times, standard consistency, expansibility and compressive strength at 2, 7, 28 and 90 days. Finally, the leaching behaviour of the vitrified MBA and hydrated cements, together with the corresponding of the "as received" MBA, was further examined using the standard leaching tests of the Toxicity Characteristic Leaching Procedure (TCLP) and the EN 12457-2. According to the obtained results, the quality of the produced cement clinkers was not affected by the addition of the vitrified MBA in the raw meal, with the trace elements detected in all leachates measured well below the corresponding regulatory limits. Copyright © 2018 Elsevier B.V. All rights reserved.

Improved oxidation of air pollutants in a non-thermal plasma

International Nuclear Information System (INIS)

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

2002-01-01

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

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.

Disposal of low-level radioactive wastes. Plasma furnace for the treatment of low-level radwastes in Switzerland. Plasma furnace for the treatment of low-level radwastes in Switzerland

International Nuclear Information System (INIS)

Hoffelner, W.; Mueller, T.; Fuenfschilling, M.R.; Jacobi, A.; Eschenbach, R.; Lutz, H.R.; Vuilleumier, C.

1994-01-01

The treatment method to be applied consists of thermal decomposition and vitrification. The facility to be constructed at the Zwilag is a plasma-arc furnace, and planning activities are heading towards the final phase. There will be only this one facility for treating in only one process step solid, mixed wastes, liquid wastes, sludges, metals, and inorganic wastes, producing vitrified waste packages ready for ultimate storage as 200-l waste drums. The main features of the plasma-arc furnace are explained. (orig./HP) [de

Plasma hearth process demonstration project

International Nuclear Information System (INIS)

Geimer, R.M.; Gillins, R.L.

1995-01-01

The Plasma Hearth Process (PHP) demonstration project is one of the key technology projects in the US Department of Energy (DOE) Office of Technology Development Mixed Waste Focus Area. The PHP is a high temperature thermal treatment process using a plasma arc torch in a stationary, refractory lined chamber that destroys organics and stabilizes the residuals in a nonleaching, vitrified waste form, greatly improving the disposability of the waste. This paper describes the PHP system and summarizes test results to date, including volume reduction, destruction and removal efficiencies for organic wastes, and emission characteristics. Tests performed so far demonstrate that the PHP adresses DOE mixed waste final waste form requirements and US Environmental Protection Agency Toxicity Characteristic Leaching Procedure requirements

Kinetic mechanism of molecular energy transfer and chemical reactions in low-temperature air-fuel plasmas.

Science.gov (United States)

Adamovich, Igor V; Li, Ting; Lempert, Walter R

2015-08-13

This work describes the kinetic mechanism of coupled molecular energy transfer and chemical reactions in low-temperature air, H2-air and hydrocarbon-air plasmas sustained by nanosecond pulse discharges (single-pulse or repetitive pulse burst). The model incorporates electron impact processes, state-specific N(2) vibrational energy transfer, reactions of excited electronic species of N(2), O(2), N and O, and 'conventional' chemical reactions (Konnov mechanism). Effects of diffusion and conduction heat transfer, energy coupled to the cathode layer and gasdynamic compression/expansion are incorporated as quasi-zero-dimensional corrections. The model is exercised using a combination of freeware (Bolsig+) and commercial software (ChemKin-Pro). The model predictions are validated using time-resolved measurements of temperature and N(2) vibrational level populations in nanosecond pulse discharges in air in plane-to-plane and sphere-to-sphere geometry; temperature and OH number density after nanosecond pulse burst discharges in lean H(2)-air, CH(4)-air and C(2)H(4)-air mixtures; and temperature after the nanosecond pulse discharge burst during plasma-assisted ignition of lean H2-mixtures, showing good agreement with the data. The model predictions for OH number density in lean C(3)H(8)-air mixtures differ from the experimental results, over-predicting its absolute value and failing to predict transient OH rise and decay after the discharge burst. The agreement with the data for C(3)H(8)-air is improved considerably if a different conventional hydrocarbon chemistry reaction set (LLNL methane-n-butane flame mechanism) is used. The results of mechanism validation demonstrate its applicability for analysis of plasma chemical oxidation and ignition of low-temperature H(2)-air, CH(4)-air and C(2)H(4)-air mixtures using nanosecond pulse discharges. Kinetic modelling of low-temperature plasma excited propane-air mixtures demonstrates the need for development of a more accurate

Near-surface storage facilities for vitrified high-level wastes

International Nuclear Information System (INIS)

Kondrat'ev, A.N.; Kulichenko, V.V.; Kryukov, I.I.; Krylova, N.V.; Paramoshkin, V.I.; Strakhov, M.V.

1980-01-01

Concurrently with the development of methods for solidifying liquid radioactive wastes, reliable and safe methods for the storage and disposal of solidified wastes are being devised in the USSR and other countries. One of the main factors affecting the choice of storage conditions for solidified wastes originating from the vitrification of high-level liquid wastes from fuel reprocessing plants is the problem of removing the heat produced by radioactive decay. In order to prevent the temperature of solidified wastes from exceeding the maximum permissible level for the material concerned, it is necessary to limit either the capacity of waste containers or the specific heat release of the wastes themselves. In order that disposal of high-level wastes in geological formations should be reliable and economic, solidified wastes undergo interim storage in near-surface storage facilities with engineered cooling systems. The paper demonstrates the relative influences of specific heat release, of the maximum permissible storage temperature for vitrified wastes and of the methods chosen for cooling wastes in order for the dimensions of waste containers to be reduced to the extent required. The effect of concentrating wastes to a given level in the vitrification process on the cost of storage in different types of storage facility is also examined. Calculations were performed for the amount of vitrified wastes produced by a reprocessing plant with a capacity of five tonnes of uranium per 24 hours. Fuel elements from reactors of the water-cooled, water-moderated type are sent for reprocessing after having been held for about two years. The dimensions of the storage facility are calculated on the assumption that it will take five years to fill

Analysis and experimental study on formation conditions of large-scale barrier-free diffuse atmospheric pressure air plasmas in repetitive pulse mode

Science.gov (United States)

Li, Lee; Liu, Lun; Liu, Yun-Long; Bin, Yu; Ge, Ya-Feng; Lin, Fo-Chang

2014-01-01

Atmospheric air diffuse plasmas have enormous application potential in various fields of science and technology. Without dielectric barrier, generating large-scale air diffuse plasmas is always a challenging issue. This paper discusses and analyses the formation mechanism of cold homogenous plasma. It is proposed that generating stable diffuse atmospheric plasmas in open air should meet the three conditions: high transient power with low average power, excitation in low average E-field with locally high E-field region, and multiple overlapping electron avalanches. Accordingly, an experimental configuration of generating large-scale barrier-free diffuse air plasmas is designed. Based on runaway electron theory, a low duty-ratio, high voltage repetitive nanosecond pulse generator is chosen as a discharge excitation source. Using the wire-electrodes with small curvature radius, the gaps with highly non-uniform E-field are structured. Experimental results show that the volume-scaleable, barrier-free, homogeneous air non-thermal plasmas have been obtained between the gap spacing with the copper-wire electrodes. The area of air cold plasmas has been up to hundreds of square centimeters. The proposed formation conditions of large-scale barrier-free diffuse air plasmas are proved to be reasonable and feasible.

Plasma flame for mass purification of contaminated air with chemical and biological warfare agents

International Nuclear Information System (INIS)

Uhm, Han S.; Shin, Dong H.; Hong, Yong C.

2006-01-01

An elimination of airborne simulated chemical and biological warfare agents was carried out by making use of a plasma flame made of atmospheric plasma and a fuel-burning flame, which can purify the interior air of a large volume in isolated spaces such as buildings, public transportation systems, and military vehicles. The plasma flame generator consists of a microwave plasma torch connected in series to a fuel injector and a reaction chamber. For example, a reaction chamber, with the dimensions of a 22 cm diameter and 30 cm length, purifies an airflow rate of 5000 lpm contaminated with toluene (the simulated chemical agent) and soot from a diesel engine (the simulated aerosol for biological agents). Large volumes of purification by the plasma flame will free mankind from the threat of airborne warfare agents. The plasma flame may also effectively purify air that is contaminated with volatile organic compounds, in addition to eliminating soot from diesel engines as an environmental application

Enthalpy probe measurements and three-dimensional modelling on air plasma jets generated by a non-transferred plasma torch with hollow electrodes

International Nuclear Information System (INIS)

Kim, Keun Su; Park, Jin Myung; Choi, Sooseok; Kim, Jongin; Hong, Sang Hee

2008-01-01

Thermal flow characteristics of air plasma jets generated by a non-transferred plasma torch with hollow electrodes are experimentally and numerically investigated in order to provide more reliable scientific and technical information, which has been insufficient for their practical applications to material and environmental industries. In this work, a thermal plasma torch of hollow electrode type is first designed and fabricated, and similarity criteria for predicting operational conditions for the scale-up to high-power torches are derived from the arc voltage characteristics measured with various operating and geometry conditions of the torch. The thermal flow characteristics of air plasma jets ejected from the torch are measured by enthalpy probe diagnostics and turn out to have relatively low temperatures of around 3000-7000 K, but show features of other unique properties, such as high energy flux, broad high temperature region and long plasma jet with moderate axial velocity, which are promising for their applications to material syntheses and hazardous waste treatments. Such high enthalpy at a relatively low temperature of air thermal plasma compared with the argon one is due to the high thermal energy residing in the vibrational and rotational states and oxygen dissociation, besides the translational states in monatomic gases such as argon. It is expected that this high specific enthalpy of the air plasma will enable material and environmental industries to treat a large amount of precursors and waste materials effectively at a lower temperature for a longer residence time by the low plasma velocity. It is also found from the measurements that the turbulence intensity influenced by the size of the electrode diameter has a significant effect on the axial and radial profiles of plasma jet properties and that a longer plasma jet is more readily achievable with a larger electrode diameter reducing the turbulence intensity in the external region of the torch. In

Evaluation of shipping doses and compositions for vitrified waste

International Nuclear Information System (INIS)

Shapiro, A.

1996-01-01

Shipments of radioactive materials must adhere to dose limits specified in the Code of Federal Regulations. This paper discusses methods for evaluating shipping doses of vitrified waste. A methodology was developed for evaluating the change in vitrification composition required to maintain shipping dose rates within limits. The point kernel codes QAD and Microshield were used to evaluate dose equivalent rates from specified waste forms and radioactivity measurements. The Origen code was utilized to provide the gamma-ray activity as a function of time from isotopic activity measurements. This gamma-ray activity served as source input for QAD. Microshield developed its own source from the given isotopic activities

Investigation of air gasification of micronized coal, mechanically activated using the plasma control of the process

Directory of Open Access Journals (Sweden)

Butakov Evgenii

2017-01-01

Full Text Available Combination of the processes of coal combustion and gasification into a single technology of mechano-chemical and plasma-chemical activation is of a considerable scientific and technological interest. Enhancement of coal reactivity at their grinding with mechanical activation is associated with an increase in the reaction rate of carbon material, and at plasma-chemical effect, the main is an increase in reactivity of the oxidizing agent caused by the high plasma temperatures of atomic oxygen. The process of gasification was studied on the 1-MW setup with tangential scroll supply of pulverized coal-air mixture and cylindrical reaction chamber. Coal ground by the standard boiler mill is fed to the disintegrator, then, it is sent to the scroll inlet of the burner-reactor with the transport air. Pulverized coal is ignited by the plasmatron of 10-kW power. In experiments on air gasification of micronized coal, carried out at the temperature in the reaction chamber of 1000-1200°C and air excess α = 0.3-1, the data on CO concentration of 11% and H2 concentration of up to 6% were obtained. Air and air-steam gasification of mechanically-activated micronized coals with plasma control was calculated using SigmaFlow software package.

Investigation of air gasification of micronized coal, mechanically activated using the plasma control of the process

Science.gov (United States)

Butakov, Evgenii; Burdukov, Anatoly; Chernetskiy, Mikhail; Kuznetsov, Victor

2017-10-01

Combination of the processes of coal combustion and gasification into a single technology of mechano-chemical and plasma-chemical activation is of a considerable scientific and technological interest. Enhancement of coal reactivity at their grinding with mechanical activation is associated with an increase in the reaction rate of carbon material, and at plasma-chemical effect, the main is an increase in reactivity of the oxidizing agent caused by the high plasma temperatures of atomic oxygen. The process of gasification was studied on the 1-MW setup with tangential scroll supply of pulverized coal-air mixture and cylindrical reaction chamber. Coal ground by the standard boiler mill is fed to the disintegrator, then, it is sent to the scroll inlet of the burner-reactor with the transport air. Pulverized coal is ignited by the plasmatron of 10-kW power. In experiments on air gasification of micronized coal, carried out at the temperature in the reaction chamber of 1000-1200°C and air excess α = 0.3-1, the data on CO concentration of 11% and H2 concentration of up to 6% were obtained. Air and air-steam gasification of mechanically-activated micronized coals with plasma control was calculated using SigmaFlow software package.

Characterization of an atmospheric pressure air plasma source for polymer surface modification

Science.gov (United States)

Yang, Shujun; Tang, Jiansheng

2013-10-01

An atmospheric pressure air plasma source was generated through dielectric barrier discharge (DBD). It was used to modify polyethyleneterephthalate (PET) surfaces with very high throughput. An equivalent circuit model was used to calculate the peak average electron density. The emission spectrum from the plasma was taken and the main peaks in the spectrum were identified. The ozone density in the down plasma region was estimated by Absorption Spectroscopy. NSF and ARC-ODU

Diffuse plasma treatment of polyamide 66 fabric in atmospheric pressure air

International Nuclear Information System (INIS)

Li, Lee; Peng, Ming-yang; Teng, Yun; Gao, Guozhen

2016-01-01

Graphical abstract: - Highlights: • A cylindrical-electrode nanosecond-pulse diffuse-discharge reactor is presented. • Large-scale non-thermal plasmas were generated steadily in atmospheric air. • Treated PA66 fabric is etched with oxygen-containing group increases. • The hydrophily of treated PA66 fabric improves effectively. • Extending the treatment time is a method to reduce the treatment frequency. - Abstract: The polyamide 66 (PA66) fabrics are hard to be colored or glued in industrial production due to the poor hydrophily. Diffuse plasma is a kind of non-thermal plasma generated at atmospheric pressure in air. This paper proposes that large-scale diffuse plasma generated between wire electrodes can be employed for improving the hydrophily of PA66 fabrics. A repetitive nanosecond-pulse diffuse-discharge reactor using a cylindrical wire electrode configuration is presented, which can generate large-scale non-thermal plasmas steadily at atmospheric pressure without any barrier dielectric. Then the reactor is used to treat PA66 fabrics in different discharge conditions. The hydrophilicity property of modified PA66 is measured by wicking test method. The modified PA66 is also analyzed by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) to prove the surface changes in physical microstructure and chemical functional groups, respectively. What's more, the effects of treatment time and treatment frequency on surface modification are investigated and discussed.

Vitrified waste form performance modeling applied to the treatment and disposal of mixed-waste sludge at the Savannah River Site

International Nuclear Information System (INIS)

Whited, A.R.; Fjeld, R.A.

1998-01-01

Vitrification, the conversion of source components into a solid amorphous glass matrix, has emerged as a viable treatment technology for low-level radioactive waste and mixed waste. To dispose of vitrified low-level waste at US Department of Energy facilities, site-specific radiological performance assessments must be conducted to demonstrate that waste glass satisfies performance objectives for environmental protection. More than 2,500 m 3 of F0006-listed low-level mixed-waste sludge stored in the Reactor Materials Department (M-Area) at the Savannah River Site (SRS) is scheduled for vitrification. This study evaluates the feasibility of on-site disposal of vitrified M-Area waste at SRS. Laboratory leaching tests that accelerate the glass corrosion process are currently the best indicators of vitrified waste form durability. A method to incorporate laboratory leaching data into performance assessments is presented. A screening-level performance assessments code is used to model trench disposal of M-Area waste glass. The allowable leach rate for vitrified M-Area waste is determined based on both a maximum radiological dose equivalent of 4 mrem/yr for the drinking water pathway and a maximum uranium concentration of 20 microg/ell in groundwater. The allowable leach rate is compared with published long-term leaching data for a wide range of waste glass compositions and test conditions. This analysis demonstrates that trench disposal of the waste glass is likely to meet applicable performance objectives if the glass is of above average durability compared with the reference set of glasses

Formation of plasma and gaseous toroidal vortices in air

International Nuclear Information System (INIS)

Yusupaliev, U.; Yusupaliev, P. U.; Shuteev, S. A.

2007-01-01

The mechanism for the formation of high-temperature (plasma) vortices and low-temperature vortex rings produced by ejecting pulsed subsonic plasma/gas jets into air was investigated experimentally. A toroidal vortex forms due to the interaction between a pulsed jet with the flow induced by this jet in the ambient medium. By analyzing the experimental data and conservation laws, an equation is derived that allows one to determine the initial propagation velocity of the vortex as a function of the characteristics of the vortex generator and the ambient medium. The results obtained by solving this equation agree well with the experimental data

Study, analysis and design of plasma torch for the elimination of hospital wastes in Chile; Estudio, analisis y diseno de antorcha de plasma para eliminacion de residuos hospitalarios en Chile

Energy Technology Data Exchange (ETDEWEB)

Diaz Ramirez, Ximena Jesus

2014-07-01

Within the field of new technologies in industry, the use of plasma is notable for its high speed of expansion and development. Currently one of its uses is the elimination of waste as it allows to avoid problems such as the formation of airborne byproducts and hazardous solids that represent a serious problem for the environment and human health. Plasma, when it is at extreme temperatures above 3,000 Celsius, causes inorganic waste to disintegrate and to vitrify on a solid residue while organic waste is converted into gases. Unlike any other thermal treatment of waste (incineration, gasification, pyrolysis, etc.) and because it is not a combustion process, but atomization of matter, no pollutant emissions into the atmosphere (dioxins and similar) or ash, there are only simple gases and an inert solid completely vitrified that can be used in the construction, for the obtaining of urban furniture, as decorative element, for example. The project proposes to develop an experimental device, laboratory plasma torch, to investigate its application in the reduction of hospital waste. It is expected to model, design and construct an experimental device that produces a plasma jet, whose temperature is adequate to perform hospital waste treatments at the laboratory level. The main objective of the project is to contribute to the generation of knowledge in the field of hospital waste reduction through the use of technological applications of plasmas, generating the necessary research for the study of art and technological development at the experimental level in the indicated field.

The generation of live offspring from vitrified oocytes.

Directory of Open Access Journals (Sweden)

L Gabriel Sanchez-Partida

Full Text Available Oocyte cryopreservation is extremely beneficial for assisted reproductive technologies, the treatment of infertility and biotechnology and offers a viable alternative to embryo freezing and ovarian grafting approaches for the generation of embryonic stem cells and live offspring. It also offers the potential to store oocytes to rescue endangered species by somatic cell nuclear transfer and for the generation of embryonic stem cells to study development in these species. We vitrified mouse oocytes using a range of concentrations of trehalose (0 to 0.3 M and demonstrated that 0.1 and 0.3 M trehalose had similar developmental rates, which were significantly different to the 0.2 M cohort (P<0.05. As mitochondria are important for fertilisation outcome, we observed that the clustering and distribution of mitochondria of the 0.2 M cohort were more affected by vitifrication than the other groups. Nevertheless, all 3 cohorts were able to develop to blastocyst, following in vitro fertilisation, although developmental rates were better for the 0.1 and 0.3 M cohorts than the 0.2 M cohort (P<0.05. Whilst blastocysts gave rise to embryonic stem-like cells, it was apparent from immunocytochemistry and RT-PCR that these cells did not demonstrate true pluripotency and exhibited abnormal karyotypes. However, they gave rise to teratomas following injection into SCID mice and differentiated into cells of each of the germinal layers following in vitro differentiation. The transfer of 2-cell embryos from the 0.1 and 0.3 M cohorts resulted in the birth of live offspring that had normal karyotypes (9/10. When 2-cell embryos from vitrified oocytes underwent vitrification, and were thawed and transferred, live offspring were obtained that exhibited normal karyotypes, with the exception of one offspring who was larger and died at 7 months. We conclude that these studies highlight the importance of the endometrial environment for the maintenance of genetic stability and

Comparing technical concepts for disposal of Belgian vitrified HLW

International Nuclear Information System (INIS)

Bel, J.; Bock, C. de; Boyazis, J.P.

2004-01-01

The choice of a suitable repository design for different categories of radioactive waste is an important element in the decisional process that will eventually lead to the waste disposal in geological ground layers during the next decades. Most countries are in the process of elaborating different technical solutions for their EBS '. Considering possible design alternatives offers more flexibility to cope with remaining uncertainties and allows optimizing some elements of the EBS in the future. However, it is not feasible to continue carrying out detailed studies for a large number of alternative design options. At different stages in the decisional process, choices, even preliminary ones, have to be made. Although the impact of different stakeholders (regulator, waste agencies, waste producers, research centers,...) in making these design choices can differ from one country to another, the choices should be based on sound, objective, clear and unambiguous justification grounds. Moreover, the arguments should be carefully reported and easy to understand by the decision makers. ONDRAF/NIRAS recently elaborated three alternative designs for the disposal of vitrified HLW. These three designs are briefly described in the next section. A first series of technological studies pointed out that the three options are feasible. It would however be unreasonable to continue R and D work on all three alternatives in parallel. It is therefore planned to make a preliminary choice of a reference design for the vitrified HLW in 2003. This selection will depend on the way the alternative design options can be evaluated against a number of criteria, mainly derived from general repository design requirements. The technique of multi-criteria analysis (MCA) will be applied as a tool for making the optimum selection, considering all selection criteria and considering different strategic approaches. This paper describes the used methodology. The decision on the actual selection will be

Plasma treatment of INEL soil contaminated with heavy metals

International Nuclear Information System (INIS)

Detering, B.A.; Batdorf, J.A.

1992-01-01

INEL soil spiked with inorganic salts of chromium, lead, mercury, silver, and zinc was melted in a 150 kW plasma furnace to produce a glassy slag product. This glassy slag is an environmentally safe waste form. In order to reduce the melting temperature of the soil, sodium carbonate was added to half of the test batches. Random sample from each batch of glassy slag product were analyzed by an independent laboratory for total metals concentration and leachability of metals via the Environmental Protection Agency (EPA) toxicity characterization leaching procedure (RCLP) tests. These tests showed the residual metals were very tightly bound to the slag matrix and were within EPA TCLP limits under these test conditions. Additionally, scanning electron microscopy (SEM) and emissions dispersive spectroscopy (EDS) analysis of the vitrified soil also confirmed that the added metals present in the vitrified soil were totally contained in the crystalline phase as distinct oxide crystallites

Surface modification of chitosan/PEO nanofibers by air dielectric barrier discharge plasma for acetylcholinesterase immobilization

Energy Technology Data Exchange (ETDEWEB)

Dorraki, Naghme, E-mail: n.dorraki@web.sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Safa, Nasrin Navab [Laser and Plasma Research Institute, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Jahanfar, Mehdi [Protein Research Center, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Ghomi, Hamid [Laser and Plasma Research Institute, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Ranaei-Siadat, Seyed-Omid [Protein Research Center, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of)

2015-09-15

Highlights: • We used an economical and effective method for surface modification. • Chitosan/PEO nanofibrous membranes were modified by air-DBD plasma. • The most NH{sub 3}{sup +} group was generated on the 6 min plasma modified membrane. • We immobilized acetylcholinesterase on the plasma modified and unmodified membranes. • More enzyme activity was detected on the modified membrane by plasma. - Abstract: There are different methods to modify polymer surfaces for biological applications. In this work we have introduced air-dielectric barrier discharge (DBD) plasma at atmospheric pressure as an economical and safe method for modifying the surface of electrospun chitosan/PEO (90/10) nanofibers for acetylcholinesterase (AChE) immobilization. According to the contact angle measurement results, the nanofibers become highly hydrophilic when they are exposed to the DBD plasma for 6 min in compared to unmodified membrane. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) results reveal hydroxyl, C=O and NH{sub 3}{sup +} polar groups increment after 6 min plasma treatment. Contact angle measurements and ATR-FTIR results are confirmed by X-ray photoelectron spectroscopy (XPS). AChE at pH 7.4 carries a negative charge and after immobilization on the surface of plasma-treated nanofibrous membrane attracts the NH{sub 3}{sup +} group and more enzyme activity is detected on the plasma-modified nanofibers for 6 min in compared to unmodified nanofibers. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) are used for the surface topography and morphology characterization. The results have proved that air-DBD plasma is a suitable method for chitosan/PEO nanofibrous membrane modification as a biodegradable and functionalized substrate for enzyme immobilization.

Air-water ‘tornado’-type microwave plasmas applied for sugarcane biomass treatment

Science.gov (United States)

Bundaleska, N.; Tatarova, E.; Dias, F. M.; Lino da Silva, M.; Ferreira, C. M.; Amorim, J.

2014-02-01

The production of cellulosic ethanol from sugarcane biomass is an attractive alternative to the use of fossil fuels. Pretreatment is needed to separate the cellulosic material, which is packed with hemicellulose and lignin in cell wall of sugarcane biomass. A microwave ‘tornado’-type air-water plasma source operating at 2.45 GHz and atmospheric pressure has been applied for this purpose. Samples of dry and wet biomass (˜2 g) have been exposed to the late afterglow plasma stream. The experiments demonstrate that the air-water highly reactive plasma environment provides a number of long-lived active species able to destroy the cellulosic wrapping. Scanning electron microscopy has been applied to analyse the morphological changes occurring due to plasma treatment. The effluent gas streams have been analysed by Fourier-transform infrared spectroscopy (FT-IR). Optical emission spectroscopy and FT-IR have been applied to determine the gas temperature in the discharge and late afterglow plasma zones, respectively. The optimal range of the operational parameters is discussed along with the main active species involved in the treatment process. Synergistic effects can result from the action of singlet O2(a 1Δg) oxygen, NO2, nitrous acid HNO2 and OH hydroxyl radical.

A numerical simulation study on active species production in dense methane-air plasma discharge

Science.gov (United States)

Gui, LI; Muyang, QIAN; Sanqiu, LIU; Huaying, CHEN; Chunsheng, REN; Dezhen, WANG

2018-01-01

Recently, low-temperature atmospheric pressure plasmas have been proposed as a potential type of ‘reaction carrier’ for the conversion of methane into value-added chemicals. In this paper, the multi-physics field coupling software of COMSOL is used to simulate the detailed discharge characteristics of atmospheric pressure methane-air plasma. A two-dimensional axisymmetric fluid model is constructed, in which 77 plasma chemical reactions and 32 different species are taken into account. The spatial density distributions of dominant charged ions and reactive radical species, such as {{{CH}}}4+, {{{CH}}}3+, {{{N}}}2+, {{{O}}}2+, H, O, CH3, and CH2, are presented, which is due to plasma chemical reactions of methane/air dissociation (or ionization) and reforming of small fragment radical species. The physicochemical mechanisms of methane dissociation and radical species recombination are also discussed and analyzed.

Characterization of Wet Air Plasma Jet Powered by Sinusoidal High Voltage and Nanosecond Pulses for Plasma Agricultural Application

Science.gov (United States)

Takashima, Keisuke; Shimada, Keisuke; Konishi, Hideaki; Kaneko, Toshiro

2015-09-01

Not only for the plasma sterilization but also for many of plasma life-science applications, atmospheric pressure plasma devices that allowed us to control its state and reactive species production are deserved to resolve the roles of the chemical species. Influence of the hydroxyl radical and ozone on germination of conidia of a strawberry pathogen is presented. Water addition to air plasma jet significantly improves germination suppression performance, while measured reactive oxygen species (ROS) are reduced. Although the results show a negative correlation between ROS and the germination suppression, this infers the importance of chemical composition generated by plasma. For further control of the plasma product, a plasma jet powered by sinusoidal high voltage and nanosecond pulses is developed and characterized with the voltage-charge Lissajous. Control of breakdown phase and discharge power by pulse-imposed phase is presented. This work is supported by JSPS KAKENHI Grant-in-Aid for Young Scientists (B) Grant Number 15K17480 and Exploratory Research Grant Number 23644199.

Interagency cooperation in the development of a cost-effective transportation and disposal solution for vitrified radium bearing material

International Nuclear Information System (INIS)

Smith, M.L.; Nixon, D.A.; Stone, T.J.; Tope, W.G.; Vogel, R.A.; Allen, R.B.; Schofield, W.D.

1996-01-01

Fernald radium bearing ore residue waste, stored within Silos 1 and 2 (K-65) and Silo 3 waste, will be vitrified for disposal at the Nevada Test Site (NTS). A comprehensive, parametric evaluation of waste form, shielding requirements, packaging, and transportation alternatives was completed to identify the safest, most cost-effective approach. The impacts of waste loading, waste form, regulatory requirements, NTS waste acceptance criteria, as-low-as-resonably-achievable principles, and material handling costs were factored into the recommended approach. Through cooperative work between the U.S. Department of Energy (DOE) and the U.S. Department of Transportation (DOT), the vitrified K-65 and Silo 3 radioactive material will be classified consistent with the regulations promulgated by DOT in the September 28, 1995 Federal Register. These new regulations adopt International Atomic Energy Agency language to promote a consistent approach for the transportation and management of radioactive material between the international community and the DOT. Use of the new regulations allows classification of the vitrified radioactive material from the Fernald silos under the designation of low specific activity-II and allows the development of a container that is optimized to maximize payload while minimizing internal void space, external surface radiation levels, and external volume. This approach minimizes the required number of containers and shipments, and the related transportation and disposal costs

Interagency cooperation in the development of a cost-effective transportation and disposal solution for vitrified radium bearing material

Energy Technology Data Exchange (ETDEWEB)

Smith, M.L.; Nixon, D.A.; Stone, T.J.; Tope, W.G.; Vogel, R.A. [Fernald Environmental Restoration Management Corp., Cincinnati, OH (United States); Allen, R.B. [USDOE, Fernald Area Office, Cincinnati, OH (United States); Schofield, W.D. [Foster Wheeler Environmental Corp. (United States)

1996-02-01

Fernald radium bearing ore residue waste, stored within Silos 1 and 2 (K-65) and Silo 3 waste, will be vitrified for disposal at the Nevada Test Site (NTS). A comprehensive, parametric evaluation of waste form, shielding requirements, packaging, and transportation alternatives was completed to identify the safest, most cost-effective approach. The impacts of waste loading, waste form, regulatory requirements, NTS waste acceptance criteria, as-low-as-resonably-achievable principles, and material handling costs were factored into the recommended approach. Through cooperative work between the U.S. Department of Energy (DOE) and the U.S. Department of Transportation (DOT), the vitrified K-65 and Silo 3 radioactive material will be classified consistent with the regulations promulgated by DOT in the September 28, 1995 Federal Register. These new regulations adopt International Atomic Energy Agency language to promote a consistent approach for the transportation and management of radioactive material between the international community and the DOT. Use of the new regulations allows classification of the vitrified radioactive material from the Fernald silos under the designation of low specific activity-II and allows the development of a container that is optimized to maximize payload while minimizing internal void space, external surface radiation levels, and external volume. This approach minimizes the required number of containers and shipments, and the related transportation and disposal costs.

Plasma vitrification of waste materials

Science.gov (United States)

McLaughlin, David F.; Dighe, Shyam V.; Gass, William R.

1997-01-01

This invention provides a process wherein hazardous or radioactive wastes in the form of liquids, slurries, or finely divided solids are mixed with finely divided glassformers (silica, alumina, soda, etc.) and injected directly into the plume of a non-transferred arc plasma torch. The extremely high temperatures and heat transfer rates makes it possible to convert the waste-glassformer mixture into a fully vitrified molten glass product in a matter of milliseconds. The molten product may then be collected in a crucible for casting into final wasteform geometry, quenching in water, or further holding time to improve homogeneity and eliminate bubbles.

Plasma vitrification of waste materials

International Nuclear Information System (INIS)

McLaughlin, D.F.; Dighe, S.V.; Gass, W.R.

1997-01-01

This invention provides a process wherein hazardous or radioactive wastes in the form of liquids, slurries, or finely divided solids are mixed with finely divided glassformers (silica, alumina, soda, etc.) and injected directly into the plume of a non-transferred arc plasma torch. The extremely high temperatures and heat transfer rates makes it possible to convert the waste-glassformer mixture into a fully vitrified molten glass product in a matter of milliseconds. The molten product may then be collected in a crucible for casting into final wasteform geometry, quenching in water, or further holding time to improve homogeneity and eliminate bubbles. 4 figs

A parametric study of the microwave plasma-assisted combustion of premixed ethylene/air mixtures

Science.gov (United States)

Fuh, Che A.; Wu, Wei; Wang, Chuji

2017-11-01

A parametric study of microwave argon plasma assisted combustion (PAC) of premixed ethylene/air mixtures was carried out using visual imaging, optical emission spectroscopy and cavity ringdown spectroscopy as diagnostic tools. The parameters investigated included the plasma feed gas flow rate, the plasma power, the fuel equivalence ratio and the total flow rate of the fuel/air mixture. The combustion enhancement effects were characterized by the minimum ignition power, the flame length and the fuel efficiency of the combustor. It was found that: (1) increasing the plasma feed gas flow rate resulted in a decrease in the flame length, an increase in the minimum ignition power for near stoichiometric fuel equivalence ratios and a corresponding decrease in the minimum ignition power for ultra-lean and rich fuel equivalence ratios; (2) at a constant plasma power, increasing the total flow rate of the ethylene/air mixture from 1.0 slm to 1.5 slm resulted in an increase in the flame length and a reduction in the fuel efficiency; (3) increasing the plasma power resulted in a slight increase in flame length as well as improved fuel efficiency with fewer C2(d) and CH(A) radicals present downstream of the flame; (4) increasing the fuel equivalence ratio caused an increase in flame length but at a reduced fuel efficiency when plasma power was kept constant; and (5) the ground state OH(X) number density was on the order of 1015 molecules/cm3 and was observed to drop downstream along the propagation axis of the flame at all parameters investigated. Results suggest that each of the parameters independently influences the PAC processes.

Chemical kinetics and relaxation of non-equilibrium air plasma generated by energetic photon and electron beams

International Nuclear Information System (INIS)

Maulois, Melissa; Ribière, Maxime; Eichwald, Olivier; Yousfi, Mohammed; Azaïs, Bruno

2016-01-01

The comprehension of electromagnetic perturbations of electronic devices, due to air plasma-induced electromagnetic field, requires a thorough study on air plasma. In the aim to understand the phenomena at the origin of the formation of non-equilibrium air plasma, we simulate, using a volume average chemical kinetics model (0D model), the time evolution of a non-equilibrium air plasma generated by an energetic X-ray flash. The simulation is undertaken in synthetic air (80% N_2 and 20% O_2) at ambient temperature and atmospheric pressure. When the X-ray flash crosses the gas, non-relativistic Compton electrons (low energy) and a relativistic Compton electron beam (high energy) are simultaneously generated and interact with the gas. The considered chemical kinetics scheme involves 26 influent species (electrons, positive ions, negative ions, and neutral atoms and molecules in their ground or metastable excited states) reacting following 164 selected reactions. The kinetics model describing the plasma chemistry was coupled to the conservation equation of the electron mean energy, in order to calculate at each time step of the non-equilibrium plasma evolution, the coefficients of reactions involving electrons while the energy of the heavy species (positive and negative ions and neutral atoms and molecules) is assumed remaining close to ambient temperature. It has been shown that it is the relativistic Compton electron beam directly created by the X-ray flash which is mainly responsible for the non-equilibrium plasma formation. Indeed, the low energy electrons (i.e., the non-relativistic ones) directly ejected from molecules by Compton collisions contribute to less than 1% on the creation of electrons in the plasma. In our simulation conditions, a non-equilibrium plasma with a low electron mean energy close to 1 eV and a concentration of charged species close to 10"1"3" cm"−"3 is formed a few nanoseconds after the peak of X-ray flash intensity. 200 ns after the

Computations of the Power to Sustain Plasma in Air with Relevance to Aerospace Technology

National Research Council Canada - National Science Library

Vidmar, Robert

2004-01-01

... level to 300,000 ft. An air chemistry code was upgraded and optimized for air-plasma research with key reactions that are functions of the reduced electric field, E/N, with a maximum value of 2E-15 V-sq cm...

Air trichloroethylene oxidation in a corona plasma-catalytic reactor

Science.gov (United States)

Masoomi-Godarzi, S.; Ranji-Burachaloo, H.; Khodadadi, A. A.; Vesali-Naseh, M.; Mortazavi, Y.

2014-08-01

The oxidative decomposition of trichloroethylene (TCE; 300 ppm) by non-thermal corona plasma was investigated in dry air at atmospheric pressure and room temperature, both in the absence and presence of catalysts including MnOx, CoOx. The catalysts were synthesized by a co-precipitation method. The morphology and structure of the catalysts were characterized by BET surface area measurement and Fourier Transform Infrared (FTIR) methods. Decomposition of TCE and distribution of products were evaluated by a gas chromatograph (GC) and an FTIR. In the absence of the catalyst, TCE removal is increased with increases in the applied voltage and current intensity. Higher TCE removal and CO2 selectivity is observed in presence of the corona and catalysts, as compared to those with the plasma alone. The results show that MnOx and CoOx catalysts can dissociate the in-plasma produced ozone to oxygen radicals, which enhances the TCE decomposition.

Interaction of plasma-facing materials with air and steam

International Nuclear Information System (INIS)

Druyts, F.; Fays, J.; Wu, C.H.

2002-01-01

In the design of ITER-FEAT, several candidate materials are foreseen for plasma-facing components of the divertor (tungsten, carbon fibre-reinforced composites (CFC), molybdenum) and the first wall (beryllium). In the view of accidental scenarios such as a loss of coolant accident or a loss of vacuum accident the reaction between these materials and steam or air remains a safety concern. To provide kinetic data, describing the chemical reactivity of plasma-facing materials in air and steam, we used coupled thermogravimetry/quadrupole mass spectrometry. In this paper we present the results of a screening investigation that compares the oxidation rates of tungsten, molybdenum, CFC and beryllium in the temperature range 300-700 deg. C. From the thermogravimetry and mass spectrometry results we obtained the reaction rates as a function of temperature. For the metals tungsten, molybdenum and beryllium, a transition is observed between protective oxidation at lower temperatures and non-protective oxidation at higher temperatures. This transition temperature lies in the range 500-550 deg. C for tungsten and molybdenum, which is lower than for beryllium. At above temperatures 550 deg. C, the oxides formed on molybdenum and tungsten volatilise. This increases the oxidation rate dramatically and can lead to mobilisation of activation products in a fusion reactor. We also performed experiments on both undoped CFC and CFC doped with 8-10% silicon. The influence of silicon doping on the chemical reactivity of CFC's in air is discussed

State-of-the-art review of quality assurance techniques for vitrified high level waste

International Nuclear Information System (INIS)

Miller, P.L.H.

1984-07-01

Quality assurance is required for certain chemical and physical properties of both the molten glass pour and the solidified glass within the stainless steel container. It is also required to monitor the physical condition of the container lid weld. A review is presented of techniques which are used or which might be adapted for use in the quality assurance of vitrified high level waste. For the most part only non-intrusive methods have been considered, however, some techniques which are not strictly non-intrusive have been reviewed where a non-intrusive technique has not been identified or where there are other advantages associated with the particular technique. In order to identify suitable candidate techniques reference has been made to an extensive literature survey and experts in the fields of nuclear waste technology, glass technology, non-destructive testing, chemical analysis and remote analysis have been contacted. The opinions of manufacturers and users of specific techniques have also been sought. A summary is also given of those techniques which can most readily be applied to the problem of quality assurance for vitrified waste as well as recommendations for further research into techniques which might be adapted to suit this application. (author)

Experimental investigation of ultraviolet laser induced plasma density and temperature evolution in air

International Nuclear Information System (INIS)

Thiyagarajan, Magesh; Scharer, John

2008-01-01

We present measurements and analysis of laser induced plasma neutral densities and temperatures in dry air by focusing 200 mJ, 10 MW high power, 193 nm ultraviolet ArF (argon fluoride) laser radiation to a 30 μm radius spot size. We examine these properties that result from multiphoton and collisional cascade processes for pressures ranging from 40 Torr to 5 atm. A laser shadowgraphy diagnostic technique is used to obtain the plasma electron temperature just after the shock front and this is compared with optical emission spectroscopic measurements of nitrogen rotational and vibrational temperatures. Two-color laser interferometry is employed to measure time resolved spatial electron and neutral density decay in initial local thermodynamic equilibrium (LTE) and non-LTE conditions. The radiating species and thermodynamic characteristics of the plasma are analyzed by means of optical emission spectroscopy (OES) supported by SPECAIR, a special OES program for air constituent plasmas. Core plasma rotational and vibrational temperatures are obtained from the emission spectra from the N 2 C-B(2+) transitions by matching the experimental spectrum results with the SPECAIR simulation results and the results are compared with the electron temperature just behind the shock wave. The plasma density decay measurements are compared with a simplified electron density decay model that illustrates the dominant three-and two-body recombination terms with good correlation

Handling of spent nuclear fuel and final storage of vitrified high level reprocessing waste

International Nuclear Information System (INIS)

1978-01-01

A summary of the planning of transportation and plant design in the Swedish KBS project on management and disposal reprocessed radioactive waste. It describes a transportation system, a central storage facility for used fuel elements, a plant for intermediate storage and encapsulation and a final repository for the vitrified waste. Accounts are given for the reprocessing and vitrification. The safety of the entire system is discussed

Study, analysis and design of plasma torch for the elimination of hospital wastes in Chile

International Nuclear Information System (INIS)

Diaz Ramirez, Ximena Jesus

2014-01-01

Within the field of new technologies in industry, the use of plasma is notable for its high speed of expansion and development. Currently one of its uses is the elimination of waste as it allows to avoid problems such as the formation of airborne byproducts and hazardous solids that represent a serious problem for the environment and human health. Plasma, when it is at extreme temperatures above 3,000 Celsius, causes inorganic waste to disintegrate and to vitrify on a solid residue while organic waste is converted into gases. Unlike any other thermal treatment of waste (incineration, gasification, pyrolysis, etc.) and because it is not a combustion process, but atomization of matter, no pollutant emissions into the atmosphere (dioxins and similar) or ash, there are only simple gases and an inert solid completely vitrified that can be used in the construction, for the obtaining of urban furniture, as decorative element, for example. The project proposes to develop an experimental device, laboratory plasma torch, to investigate its application in the reduction of hospital waste. It is expected to model, design and construct an experimental device that produces a plasma jet, whose temperature is adequate to perform hospital waste treatments at the laboratory level. The main objective of the project is to contribute to the generation of knowledge in the field of hospital waste reduction through the use of technological applications of plasmas, generating the necessary research for the study of art and technological development at the experimental level in the indicated field

Elevated plasma endothelin-1 and pulmonary arterial pressure in children exposed to air pollution.

Science.gov (United States)

Calderón-Garcidueñas, Lilian; Vincent, Renaud; Mora-Tiscareño, Antonieta; Franco-Lira, Maricela; Henríquez-Roldán, Carlos; Barragán-Mejía, Gerardo; Garrido-García, Luis; Camacho-Reyes, Laura; Valencia-Salazar, Gildardo; Paredes, Rogelio; Romero, Lina; Osnaya, Hector; Villarreal-Calderón, Rafael; Torres-Jardón, Ricardo; Hazucha, Milan J; Reed, William

2007-08-01

Controlled exposures of animals and humans to particulate matter (PM) or ozone air pollution cause an increase in plasma levels of endothelin-1, a potent vasoconstrictor that regulates pulmonary arterial pressure. The primary objective of this field study was to determine whether Mexico City children, who are chronically exposed to levels of PM and O(3) that exceed the United States air quality standards, have elevated plasma endothelin-1 levels and pulmonary arterial pressures. We conducted a study of 81 children, 7.9 +/- 1.3 years of age, lifelong residents of either northeast (n = 19) or southwest (n = 40) Mexico City or Polotitlán (n = 22), a control city with PM and O(3) levels below the U.S. air quality standards. Clinical histories, physical examinations, and complete blood counts were done. Plasma endothelin-1 concentrations were determined by immunoassay, and pulmonary arterial pressures were measured by Doppler echocardiography. Mexico City children had higher plasma endothelin-1 concentrations compared with controls (p < 0.001). Mean pulmonary arterial pressure was elevated in children from both northeast (p < 0.001) and southwest (p < 0.05) Mexico City compared with controls. Endothelin-1 levels in Mexico City children were positively correlated with daily outdoor hours (p = 0.012), and 7-day cumulative levels of PM air pollution < 2.5 mum in aerodynamic diameter (PM(2.5)) before endothelin-1 measurement (p = 0.03). Chronic exposure of children to PM(2.5) is associated with increased levels of circulating endothelin-1 and elevated mean pulmonary arterial pressure.

Elevated Plasma Endothelin-1 and Pulmonary Arterial Pressure in Children Exposed to Air Pollution

Science.gov (United States)

Calderón-Garcidueñas, Lilian; Vincent, Renaud; Mora-Tiscareño, Antonieta; Franco-Lira, Maricela; Henríquez-Roldán, Carlos; Barragán-Mejía, Gerardo; Garrido-García, Luis; Camacho-Reyes, Laura; Valencia-Salazar, Gildardo; Paredes, Rogelio; Romero, Lina; Osnaya, Hector; Villarreal-Calderón, Rafael; Torres-Jardón, Ricardo; Hazucha, Milan J.; Reed, William

2007-01-01

Background Controlled exposures of animals and humans to particulate matter (PM) or ozone air pollution cause an increase in plasma levels of endothelin-1, a potent vasoconstrictor that regulates pulmonary arterial pressure. Objectives The primary objective of this field study was to determine whether Mexico City children, who are chronically exposed to levels of PM and O3 that exceed the United States air quality standards, have elevated plasma endothelin-1 levels and pulmonary arterial pressures. Methods We conducted a study of 81 children, 7.9 ± 1.3 years of age, lifelong residents of either northeast (n = 19) or southwest (n = 40) Mexico City or Polotitlán (n = 22), a control city with PM and O3 levels below the U.S. air quality standards. Clinical histories, physical examinations, and complete blood counts were done. Plasma endothelin-1 concentrations were determined by immunoassay, and pulmonary arterial pressures were measured by Doppler echocardiography. Results Mexico City children had higher plasma endothelin-1 concentrations compared with controls (p < 0.001). Mean pulmonary arterial pressure was elevated in children from both northeast (p < 0.001) and southwest (p < 0.05) Mexico City compared with controls. Endothelin-1 levels in Mexico City children were positively correlated with daily outdoor hours (p = 0.012), and 7-day cumulative levels of PM air pollution < 2.5 μm in aerodynamic diameter (PM2.5) before endothelin-1 measurement (p = 0.03). Conclusions Chronic exposure of children to PM2.5 is associated with increased levels of circulating endothelin-1 and elevated mean pulmonary arterial pressure. PMID:17687455

Cold atmospheric air plasma sterilization against spores and other microorganisms of clinical interest.

Science.gov (United States)

Klämpfl, Tobias G; Isbary, Georg; Shimizu, Tetsuji; Li, Yang-Fang; Zimmermann, Julia L; Stolz, Wilhelm; Schlegel, Jürgen; Morfill, Gregor E; Schmidt, Hans-Ulrich

2012-08-01

Physical cold atmospheric surface microdischarge (SMD) plasma operating in ambient air has promising properties for the sterilization of sensitive medical devices where conventional methods are not applicable. Furthermore, SMD plasma could revolutionize the field of disinfection at health care facilities. The antimicrobial effects on Gram-negative and Gram-positive bacteria of clinical relevance, as well as the fungus Candida albicans, were tested. Thirty seconds of plasma treatment led to a 4 to 6 log(10) CFU reduction on agar plates. C. albicans was the hardest to inactivate. The sterilizing effect on standard bioindicators (bacterial endospores) was evaluated on dry test specimens that were wrapped in Tyvek coupons. The experimental D(23)(°)(C) values for Bacillus subtilis, Bacillus pumilus, Bacillus atrophaeus, and Geobacillus stearothermophilus were determined as 0.3 min, 0.5 min, 0.6 min, and 0.9 min, respectively. These decimal reduction times (D values) are distinctly lower than D values obtained with other reference methods. Importantly, the high inactivation rate was independent of the material of the test specimen. Possible inactivation mechanisms for relevant microorganisms are briefly discussed, emphasizing the important role of neutral reactive plasma species and pointing to recent diagnostic methods that will contribute to a better understanding of the strong biocidal effect of SMD air plasma.

Particle-in-cell simulations of multi-MeV pulsed X-ray induced air plasmas at low pressures

International Nuclear Information System (INIS)

Ribière, M.; D'Almeida, T.; Gaufridy de Dortan, F. de; Maulois, M.; Delbos, C.; Garrigues, A.; Cessenat, O.; Azaïs, B.

2016-01-01

A full kinetic modelling of the charge particles dynamics generated upon the irradiation of an air-filled cavity by a multi-MeV pulsed x-ray is performed. From the calculated radiative source generated by the ASTERIX generator, we calculated the electromagnetic fields generated by x-ray induced air plasmas in a metallic cavity at different pressures. Simulations are carried out based on a Particle-In-Cell interpolation method which uses 3D Maxwell-Vlasov calculations of the constitutive charged species densities of air plasmas at different pressures at equilibrium. The resulting electromagnetic fields within the cavity are calculated for different electron densities up to 4 × 10"1"0" cm"−"3. For each air pressure, we show electronic plasma waves formation followed by Landau damping. As electron density increases, the calculations exhibit space-charged neutralization and return current formation.

Extended plasma channels created by UV laser in air and their application to control electric discharges

International Nuclear Information System (INIS)

Zvorykin, V. D.; Ionin, A. A.; Levchenko, A. O.; Seleznev, L. V.; Sinitsyn, D. V.; Smetanin, I. V.; Ustinovskii, N. N.; Shutov, A. V.

2015-01-01

Results are presented from a series of experimental and theoretical studies on creating weakly ionized extended plasma channels in atmospheric air by 248-nm UV laser radiation and their application to control long high-voltage discharges. The main mechanisms of air ionization by UV laser pulses with durations from 100 fs to 25 ns and intensities in the ranges of 3×10 11 –1.5×10 13 and 3×10 6 –3×10 11 W/cm 2 , respectively, which are below the threshold for optical gas breakdown, as well as the main relaxation processes in plasma with a density of 10 9 –10 17 cm −3 , are considered. It is shown that plasma channels in air can be efficiently created by amplitude-modulated UV pulses consisting of a train of subpicosecond pulses producing primary photoelectrons and a long UV pulse suppressing electron attachment and sustaining the density of free electrons in plasma. Different modes of the generation and amplification of trains of subterawatt subpicosecond pulses and amplitude-modulated UV pulses with an energy of several tens of joules were implemented on the GARPUN-MTW hybrid Ti:sapphire-KrF laser facility. The filamentation of such UV laser beams during their propagation in air over distances of up to 100 m and the parameters of the corresponding plasma channels were studied experimentally and theoretically. Laser initiation of high-voltage electric discharges and control of their trajectories by means of amplitude-modulated UV pulses, as well as the spatiotemporal structure of breakdowns in air gaps with length of up to 80 cm, were studied

Air trichloroethylene oxidation in a corona plasma-catalytic reactor

International Nuclear Information System (INIS)

Masoomi-Godarzi, S.; Ranji-Burachaloo, H.; Khodadadi, A.A.; Vesali-Naseh, M.; Mortazavi, Y.

2014-01-01

The oxidative decomposition of trichloroethylene (TCE; 300 ppm) by non-thermal corona plasma was investigated in dry air at atmospheric pressure and room temperature, both in the absence and presence of catalysts including MnO x , CoO x . The catalysts were synthesized by a co-precipitation method. The morphology and structure of the catalysts were characterized by BET surface area measurement and Fourier Transform Infrared (FTIR) methods. Decomposition of TCE and distribution of products were evaluated by a gas chromatograph (GC) and an FTIR. In the absence of the catalyst, TCE removal is increased with increases in the applied voltage and current intensity. Higher TCE removal and CO 2 selectivity is observed in presence of the corona and catalysts, as compared to those with the plasma alone. The results show that MnO x and CoO x catalysts can dissociate the in-plasma produced ozone to oxygen radicals, which enhances the TCE decomposition. (author)

Electrochemical reduction behavior of simplified simulants of vitrified radioactive waste in molten CaCl2

Science.gov (United States)

Katasho, Yumi; Yasuda, Kouji; Nohira, Toshiyuki

2018-05-01

The electrochemical reduction of two types of simplified simulants of vitrified radioactive waste, simulant 1 (glass component only: SiO2, B2O3, Na2O, Al2O3, CaO, Li2O, and ZnO) and simulant 2 (also containing long-lived fission product oxides, ZrO2, Cs2O, PdO, and SeO2), was investigated in molten CaCl2 at 1103 K. The behavior of each element was predicted from the potential-pO2- diagram constructed from thermodynamic data. After the immersion of simulant 1 into molten CaCl2 without electrolysis, the dissolution of Na, Li, and Cs was confirmed by inductively coupled plasma atomic emission spectrometry and mass spectrometry analysis of the samples. The scanning electron microscopy/energy dispersive X-ray and X-ray diffraction analyses of simulants 1 and 2 electrolyzed at 0.9 V vs. Ca2+/Ca confirmed that most of SiO2 had been reduced to Si. After the electrolysis of simulants 1 and 2, Al, Zr, and Pd remained in the solid phase. In addition, SeO2 was found to remain partially in the solid phase and partially evaporate, although a small quantity dissolved into the molten salt.

Hanford Waste Vitrification Plant Clean Air Act permit application

International Nuclear Information System (INIS)

1990-04-01

This document briefly describes the Hanford Site and provides a general overview of the Hanford Waste Vitrification Plant (HWVP). Other topics include sources of emissions, facility operating parameters, facility emissions, pollutant and radionuclide control technology and air quality. The HWVP will convert mixed wastes (high-activity radioactive and hazardous liquid wastes) to a solid vitrified form (borosilicate glass) for disposal. Mixed wastes pretreated in the Hanford Site B Plant will be pumped into double- shell tanks in the 200 East Area for interim storage. This pretreated mixed waste will be batch transferred from interim storage to the HWVP facility, where the waste will be concentrated by evaporation, treated with chemicals, and mixed with glass-forming materials. The mixture will then be continuously fed into an electrically heated glass melter. The molten glass will be poured into canisters that will be cooled, sealed, decontaminated, and stored until the vitrified product can be transferred to a geologic repository. 25 refs., 18 figs., 32 tabs

Synthesis long life storage studies surface storage of vitrified wastes

International Nuclear Information System (INIS)

Beziat, A.; Breton, E.; Ranc, G.; Gaillard, J.P.; Lagrave, H.; Hollender, F.; Jourdain, F.; Piault, E.; Garnier, J.; Lamare, V.; Duret, B.; Helie, M.; Ferry, C.; Mijuin, D.; Gagnier, E.

2004-01-01

This document is realized in the framework of the axis 3 of the law of 1991 on the radioactive wastes management. It justifies the choices concerning long time surface storage installation of vitrified wastes, called high activity wastes. The long time of the installation would reach 300 years at the maximum. These wastes represent 1 % at the maximum, of radioactive wastes in France but 95 % of the whole radioactivity. Three main objectives were followed: provide a permanent containment of radionuclides; give the possibility of wastes containers retrieval at all the time; minimize the maintenance and the control. The results allow to conclude that the long time surface storage of high activity wastes is feasible. (A.L.B.)

Survey and assessment of radioactive waste management facilities in the United States. Section 2.5. Air-cooled vault storage facilities

International Nuclear Information System (INIS)

1986-01-01

There are two basic types of air-cooled vaults for the storage of spent nuclear fuel or vitrified HLRW. The two types, differentiated by the method of air cooling used, are the open-vault concept and the closed-vault concept. The following aspects of these air-cooled vault storage facility concepts are discussed: description and operation of facilities; strucutral design considerations and analysis; nuclear design considerations and analyses; vault environmental design considerations; unique design features; and accident analysis

Air plasma treatment of liquid covered tissue: long timescale chemistry

Science.gov (United States)

Lietz, Amanda M.; Kushner, Mark J.

2016-10-01

Atmospheric pressure plasmas have shown great promise for the treatment of wounds and cancerous tumors. In these applications, the sample is usually covered by a thin layer of a biological liquid. The reactive oxygen and nitrogen species (RONS) generated by the plasma activate and are processed by the liquid before the plasma produced activation reaches the tissue. The synergy between the plasma and the liquid, including evaporation and the solvation of ions and neutrals, is critical to understanding the outcome of plasma treatment. The atmospheric pressure plasma sources used in these procedures are typically repetitively pulsed. The processes activated by the plasma sources have multiple timescales—from a few ns during the discharge pulse to many minutes for reactions in the liquid. In this paper we discuss results from a computational investigation of plasma-liquid interactions and liquid phase chemistry using a global model with the goal of addressing this large dynamic range in timescales. In modeling air plasmas produced by a dielectric barrier discharge over liquid covered tissue, 5000 voltage pulses were simulated, followed by 5 min of afterglow. Due to the accumulation of long-lived species such as ozone and N x O y , the gas phase dynamics of the 5000th discharge pulse are different from those of the first pulse, particularly with regards to the negative ions. The consequences of applied voltage, gas flow, pulse repetition frequency, and the presence of organic molecules in the liquid on the gas and liquid reactive species are discussed.

Effects of atmospheric air plasma treatment of graphite and carbon felt electrodes on the anodic current from Shewanella attached cells.

Science.gov (United States)

Epifanio, Monica; Inguva, Saikumar; Kitching, Michael; Mosnier, Jean-Paul; Marsili, Enrico

2015-12-01

The attachment of electrochemically active microorganisms (EAM) on an electrode is determined by both the chemistry and topography of the electrode surface. Pre-treatment of the electrode surface by atmospheric air plasma introduces hydrophilic functional groups, thereby increasing cell attachment and electroactivity in short-term experiments. In this study, we use graphite and carbon felt electrodes to grow the model EAM Shewanella loihica PV-4 at oxidative potential (0.2 V vs. Ag/AgCl). Cell attachment and electroactivity are measured through electrodynamic methods. Atmospheric air plasma pre-treatment increases cell attachment and current output at graphite electrodes by 25%, while it improves the electroactivity of the carbon felt electrodes by 450%. Air plasma pre-treatment decreased the coulombic efficiency on both carbon felt and graphite electrodes by 60% and 80%, respectively. Microbially produced flavins adsorb preferentially at the graphite electrode, and air plasma pre-treatment results in lower flavin adsorption at both graphite and carbon felt electrodes. Results show that air plasma pre-treatment is a feasible option to increase current output in bioelectrochemical systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of air dielectric barrier discharge plasma treatment time on surface properties of PBO fiber

International Nuclear Information System (INIS)

Wang Qian; Chen Ping; Jia Caixia; Chen, Mingxin; Li Bin

2011-01-01

In this paper, the effects of air dielectric barrier discharge (DBD) plasma treatment time on surface properties of poly(p-phenylene benzobisoxazole) (PBO) fiber were investigated. The surface characteristics of PBO fiber before and after the plasma treatments were analyzed by dynamic contact angle (DCA) analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). DCA measurements indicated that the surface wettability of PBO fiber was improved significantly by increasing the fiber surface free energy via air DBD plasma treatments. The results were confirmed by the improvement of adhesion of a kind of thermoplastic resin to PBO fiber which was observed by SEM, showing that more resin was adhering evenly to the fiber surface. AFM measurement revealed that the surface topography of PBO fiber became more complicated and the surface roughness was greatly enhanced after the plasma treatments, and XPS analysis showed that some new polar groups (e.g. -O-C=O) were introduced on plasma treated PBO fiber surface. The results of this study also showed that the surface properties of PBO fiber changed with the elongation of plasma treatment time.

Enhancement of corrosion resistance for plasma nitrided AISI 4140 steel by plain air plasma post-oxidizing

Energy Technology Data Exchange (ETDEWEB)

Wu, Jiqiang; Liu, Han; Ye, Xuemei [Jiangsu Key Laboratory of Materials Surface Technology, Changzhou University, Changzhou 213164 (China); Chai, Yating [Materials Research and Education Center, Auburn University, AL 36849 (United States); Hu, Jing, E-mail: jinghoo@126.com [Jiangsu Key Laboratory of Materials Surface Technology, Changzhou University, Changzhou 213164 (China); Materials Research and Education Center, Auburn University, AL 36849 (United States)

2015-05-25

Highlights: • Plain air was primarily used for plasma post-oxidation for AISI 4140 steel. • A thin iron oxide layer composed of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3} was formed on top of the compound layer. • The ratio of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3} was closely related to the post-oxidizing conditions. • Post-oxidizing at 673 K for 60 min brought out highest ratio of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3} and optimum corrosion resistance. - Abstract: Plasma post-oxidizing was conducted immediately after plasma nitriding in the same equipment for AISI 4140 steel, and plain air was used as the oxygen bearing gas. The cross-sectional microstructures of the treated samples were observed by optical metallography and scanning electron microcopy (SEM), and the thickness of compound layer was measured accordingly. The phases were determined by X-ray diffraction (XRD), corrosion resistance was evaluated by electrochemical polarization, and the surface morphology before and after polarization test was also observed by SEM. Meanwhile, standard Gibbs free energy of the oxidation reactions existed in Fe–O system was calculated. The results show that a thin iron oxide layer composed of magnetite (Fe{sub 3}O{sub 4}) and hematite (Fe{sub 2}O{sub 3}) is formed on top of the compound layer during plasma post-oxidizing process, and the ratio of magnetite (Fe{sub 3}O{sub 4}) to hematite (Fe{sub 2}O{sub 3}) is depended on plasma post-oxidizing temperature and time. Highest ratio of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3} is obtained while post-oxidizing at 673 K for 60 min due to lower standard Gibbs free energy and appropriate forming rate for the formation of Fe{sub 3}O{sub 4} at this temperature. The thin oxide layer brings out significant enhancement of corrosion resistance, especially at higher ratios of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3}, due to the dense and adherent characteristic of Fe{sub 3}O{sub 4} oxide. Surface images of the post-oxidizing specimen

Alteration of medieval stained-glasses. Contribution to the long-term behaviour of vitrified wastes

International Nuclear Information System (INIS)

Sterpenich, J.

1998-01-01

In this work, the behaviour of glasses during alteration have been studied in two different ways: 1)study of the alteration of medieval stained-glasses 2)experimental leaching of modelled glasses. Medieval stained-glasses have a silico-calcic and alkaline composition. It appears three different alteration modes for these glasses: 1)by condensation waters 2)by atmospheric agents 3)by porosity waters and humic acids. A chemical study of the altered areas has allowed to understand the alteration behaviour of a lot of elements: in particular transition elements, heavy metals and some rare earths. On the other hand, two vitrified wastes and a glass having the same composition of the potassic medieval stained-glasses have been leached in a static mode (pH=1 to 10, T=20 to 80 degrees Celsius, T=12 hours to 6 months). These experiments have revealed that the alteration mechanisms depend on the pH of the solution and on the chemical composition of the glass. An increasing durability of glasses in terms of the global polymerization degree has been revealed too. At last, the behaviours of glasses during alteration, observed with natural and experimental conditions, show that it is necessary to study natural analogous for predicting the long-term behaviour of vitrified wastes. (O.M.)

Leaching of vitrified high-level-active-waste in a near reality simulated repository system

International Nuclear Information System (INIS)

Froeschen, W.; Wolf, G.K.

1987-01-01

In the FRG it is planned to vitrify the high level waste from spent fuel reprocessing and to dispose of in a salt-mine. If water penetrates into the repository a highly corrosive brine (Q-brine) will be formed and radioactive material may be leached from the glasses and transported to human environment. The corrosion system of brine, corroded steel containers of the vitrified waste, and waste-glasses was investigated under near reality conditions. Experiments in hydrothermal environment were carried out including gamma radiation of the waste-glasses and ceramic In Can Lining between glasses and metallic containments. Screening experiments by application of external cobalt-gamma-radiation showed no principal changes in leaching behaviour of simulate glasses compared to leaching without radiation. Radiation effects result in pH changes mainly which are diminished by buffer capacity of Q-brine. Lining of steel containments with ceramic fleece does not reduce leaching but retards solution of Mo and Sr into brine. Decreasing of elements Sr, Cs and Mo in the near surface area of the glass and increasing of Zr and Ti has been found to be enhanced considerably in presence of canister corrosion products in Q-brine as well as in NaCl-leaching solution. (orig.) With 13 refs., 22 figs [de

Underground disposal of vitrified high level radioactive waste: a review of research and development

International Nuclear Information System (INIS)

1982-11-01

A review has been undertaken of the worldwide status of research and development related to the geological disposal of vitrified high level radioactive waste. The nature and quantities of vitrified high level waste that will arise from nuclear power generation in the UK have been estimated and considered. The safety case for establishing a geological repository would have to be based on predictive models, which could adequately represent the interactions and effects of a wide range of gradual processes and possible sudden events. No detailed repository design has yet been published, but the configuration currently favoured, in the UK and in most other countries, comprises a small number of vertical shafts, from which a network of horizontal tunnels would be excavated. Waste packages would be placed in holes drilled in the floors of the tunnels. The excavation of such a repository in hard crystalline rock, in a thick homogeneous formation of rock salt, or in the less plastic argillaceous formations, appears to be within the scope of present technology. Rock types available in the UK, which are likely to prove suitable for the accommodation of a repository, have been identified. The strategies and programmes for high level waste disposal in other countries have been reviewed. (U.K.)

Ignition phase and steady-state structures of a non-thermal air plasma

CERN Document Server

Lu Xin Pei

2003-01-01

An AC-driven, non-thermal, atmospheric pressure air plasma is generated within the gap separating a disc-shaped metal electrode and a water electrode. The ignition phase and the steady-state are studied by a high-speed CCD camera. It is found that the plasma always initiates at the surface of the water electrode. The plasma exhibits different structures depending on the polarity of the water electrode: when the water electrode plays the role of cathode, a relatively wide but visibly dim plasma column is generated. At the maximum driving voltage, the gas temperature is between 800 and 900 K, and the peak current is 67 mA; when the water electrode is anode, the plasma column narrows but increases its light emission. The gas temperature in this case is measured to be in the 1400-1500 K range, and the peak current is 81 mA.

Handling of spent nuclear fuel and final storage of vitrified high level reprocessing waste

International Nuclear Information System (INIS)

1978-01-01

The report gives a general summary of the Swedish KBS-project on management and disposal of vitrified reprocessed waste. Its final aim is to demostrate that the means of processing and managing power reactor waste in an absolutely safe way, as stipulated in the Swedish so called Conditions Act, already exist. Chapters on Storage facility for spent fuel, Intermidiate storage of reprocessed waste, Geology, Final repository, Transportation, Protection, and Siting. (L.E.)

The importance of mobile fission products for long-term safety in the case of disposal of vitrified high-level waste and spent fuel in a clay formation

International Nuclear Information System (INIS)

Marivoet, J.; Weetjens, E.

2009-01-01

In Belgium, the possibility to dispose of high-level radioactive waste in clay formations is studied since 1976. In the PAGIS report, which was the first performance assessment of the disposal of vitrified high-level waste in a clay formation and which was published in 1988, the most important contributors to the total dose via a water well pathway were 237 Np, 135 Cs and 99 Tc. Since 1988, several elements that strongly influence the calculated doses have evolved:?the inventory of long-lived mobile fission and activation products in vitrified high-level waste has been improved; the half-life of 79 Se has been re-estimated; substantial progress has been made in the determination of migration parameters of the main fission and activation products and actinides. In recent performance assessments, the actinides and 135 Cs do not significantly contribute to the total dose, as they remain confined in the host clay formation during several millions of years due to sorption on clay minerals. Consequently, the total dose resulting from the disposal of vitrified high-level waste or spent fuel is essentially due to releases of mobile fission and activation products. On the basis of recent waste inventory data and parameter values, the most important contributors to the total dose via a water well are: in the case of disposal of spent fuel: 79 Se, 129 I, 126 Sn, 36 Cl, and 99 Tc; in the case of disposal of vitrified HLW: 79 Se, 126 Sn, 36 Cl, 129 I, and 99 Tc. Important remaining uncertainties are the transfer factors of volatile fission and activation products into the vitrified waste during reprocessing and migration parameters of Se. (author)

Molecular-level removal of proteinaceous contamination from model surfaces and biomedical device materials by air plasma treatment.

Science.gov (United States)

Banerjee, K K; Kumar, S; Bremmell, K E; Griesser, H J

2010-11-01

Established methods for cleaning and sterilising biomedical devices may achieve removal of bioburden only at the macroscopic level while leaving behind molecular levels of contamination (mainly proteinaceous). This is of particular concern if the residue might contain prions. We investigated at the molecular level the removal of model and real-life proteinaceous contamination from model and practical surfaces by air plasma (ionised air) treatment. The surface-sensitive technique of X-ray photoelectron spectroscopy (XPS) was used to assess the removal of proteinaceous contamination, with the nitrogen (N1s) photoelectron signal as its marker. Model proteinaceous contamination (bovine serum albumin) adsorbed on to a model surface (silicon wafer) and the residual proteinaceous contamination resulting from incubating surgical stainless steel (a practical biomaterial) in whole human blood exhibited strong N1s signals [16.8 and 18.5 atomic percent (at.%), respectively] after thorough washing. After 5min air plasma treatment, XPS detected no nitrogen on the sample surfaces, indicating complete removal of proteinaceous contamination, down to the estimated XPS detection limit 10ng/cm(2). Applying the same plasma treatment, the 7.7at.% nitrogen observed on a clinically cleaned dental bur was reduced to a level reflective of new, as-received burs. Contact angle measurements and atomic force microscopy also indicated complete molecular-level removal of the proteinaceous contamination upon air plasma treatment. This study demonstrates the effectiveness of air plasma treatment for removing proteinaceous contamination from both model and practical surfaces and offers a method for ensuring that no molecular residual contamination such as prions is transferred upon re-use of surgical and dental instruments. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

Aqueous reactive species induced by a PCB surface micro-discharge air plasma device: a quantitative study

Science.gov (United States)

Chen, Chen; Li, Fanying; Chen, Hai-Lan; Kong, Michael G.

2017-11-01

This paper presents a quantitative investigation on aqueous reactive species induced by air plasma generated from a printed circuit board surface micro-discharge (SMD) device. Under the conditions amenable for proliferation of mammalian cells, concentrations of ten types of reactive oxygen and nitrogen species (RONS) in phosphate buffering solution (PBS) are measured by chemical fluorescent assays and electron spin resonance spectroscopy (ESR). Results show that concentrations of several detected RNS (NO2- , NO3- , peroxynitrites, and NO2\\centerdot ) are higher than those of ROS (H2O2, O2\\centerdot - , and 1O2) in the air plasma treated solution. Concentrations of NO3- can reach 150 times of H2O2 with 60 s plasma treatment. For short-lived species, the air plasma generates more copious peroxynitrite than other RONS including NO2\\centerdot , O2\\centerdot - , 1O2, and N{{O}\\centerdot } in PBS. In addition, the existence of reaction between H2O2 and NO2- /HNO2 to produce peroxynitrite is verified by the chemical scavenger experiments. The reaction relations between detected RONS are also discussed.

Air plasma treatment of liquid covered tissue: long timescale chemistry

International Nuclear Information System (INIS)

Lietz, Amanda M; Kushner, Mark J

2016-01-01

Atmospheric pressure plasmas have shown great promise for the treatment of wounds and cancerous tumors. In these applications, the sample is usually covered by a thin layer of a biological liquid. The reactive oxygen and nitrogen species (RONS) generated by the plasma activate and are processed by the liquid before the plasma produced activation reaches the tissue. The synergy between the plasma and the liquid, including evaporation and the solvation of ions and neutrals, is critical to understanding the outcome of plasma treatment. The atmospheric pressure plasma sources used in these procedures are typically repetitively pulsed. The processes activated by the plasma sources have multiple timescales—from a few ns during the discharge pulse to many minutes for reactions in the liquid. In this paper we discuss results from a computational investigation of plasma–liquid interactions and liquid phase chemistry using a global model with the goal of addressing this large dynamic range in timescales. In modeling air plasmas produced by a dielectric barrier discharge over liquid covered tissue, 5000 voltage pulses were simulated, followed by 5 min of afterglow. Due to the accumulation of long-lived species such as ozone and N x O y , the gas phase dynamics of the 5000th discharge pulse are different from those of the first pulse, particularly with regards to the negative ions. The consequences of applied voltage, gas flow, pulse repetition frequency, and the presence of organic molecules in the liquid on the gas and liquid reactive species are discussed. (paper)

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

International Nuclear Information System (INIS)

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

2016-01-01

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

Transmission characteristics of the kinematics of the laser-plasma shock wave in air in compton scattering

International Nuclear Information System (INIS)

Hao Dongshan; Xie Hongjun

2006-01-01

By comparing the kinematical equation of a shock wave in free air, the study of transmission characteristics of the laser plasma shock wave in Compton scattering is presented. The results show that the attenuation course of the kinematics of he laser plasma shock wave is related not only with the explosion fountainhead and the characteristics of the explosion course, total energy release, air elastic, but also with multi-photon nonlinear Compton scattering. Because of the scattering the initial radius of the shock wave increases, the attenuation course shortens, the energy metastasis efficiency rises. The results of the numerical analysis and the actual values of the shock waves in air by a way intense explosion are very tallying. (authors)

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

International Nuclear Information System (INIS)

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

2003-01-01

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

Surface treatment of aramid fiber by air dielectric barrier discharge plasma at atmospheric pressure

International Nuclear Information System (INIS)

Jia Caixia; Chen Ping; Liu Wei; Li Bin; Wang Qian

2011-01-01

Aramid fiber samples are treated by air dielectric barrier discharge (DBD) plasma at atmospheric pressure; the plasma treatment time is investigated as the major parameter. The effects of this treatment on the fiber surface physical and chemical properties are studied by using surface characterization techniques. Scanning electron microscopy (SEM) is performed to determine the surface morphology changes, X-ray photoelectron spectroscopy (XPS) is analyzed to reveal the surface chemical composition variations and dynamic contact angle analysis (DCAA) is used to examine the changes of the fiber surface wettability. In addition, the wetting behavior of a kind of thermoplastic resin, poly(phthalazinone ether sulfone ketone) (PPESK), on aramid fiber surface is also observed by SEM photos. The study shows that there seems to be an optimum treatment condition for surface modification of aramid fiber by the air DBD plasma. In this paper, after the 12 s, 27.6 W/cm 3 plasma treatment the aramid fiber surface roughness is significantly improved, some new oxygen-containing groups such as C-O, C=O and O=C-O are generated on the fiber surface and the fiber surface wettability is greatly enhanced, which results in the better wetting behavior of PPESK resin on the plasma-treated aramid fiber.

Protection of active implant electronics with organosilicon open air plasma coating for plastic overmolding

Directory of Open Access Journals (Sweden)

Zeppenfeld Matthias

2016-09-01

Full Text Available To overcome challenges for manufacturing of modern smart medical plastic parts by injection molding, e.g. for active implants, the optimization of the interface between electronics and the polymer component concerning adhesion and diffusion behavior is crucial. Our results indicate that a nano-sized SiOxCyHz layer formed by plasma-enhanced chemical vapour deposition (PE-CVD via open air atmospheric pressure plasma jet (APPJ and by use of a hexamthyldisiloxane (HMDSO precursor can form a non-corrosive, anti-permeable and biocompatible coating. Due to the open air character of the APPJ process an inline coating before overmolding could be an easy applicable method and a promising advancement.

Effect of streamer plasma air purifier on sbs symptoms and performance of office work

DEFF Research Database (Denmark)

Zhang, X.J.; Fang, Lei; Wargocki, Pawel

2011-01-01

Subjective experiments were conducted to evaluate the effect of a streamer plasma air purifier on perceived air quality, SBS symptoms and performance of office work during 5-hour exposure of 32 recruited subjects in field laboratory in which real materials were used to establishing a realistic...... level of air pollution. Intensity of SBS symptoms were indicated using visual-analogue scales. Subjects’ performance was evaluated with several computer tasks. The results show that operation of the air purifiers improved perceived air quality and reduced the odor intensity of indoor air. Eye dryness...... symptom was found significantly improved when the air purifiers were used but no other SBS symptoms or performance of office work were improved when the air purifiers were in operation compared to the condition when they were off....

Development of Polysulfone Hollow Fiber Porous Supports for High Flux Composite Membranes: Air Plasma and Piranha Etching

Directory of Open Access Journals (Sweden)

Ilya Borisov

2017-02-01

Full Text Available For the development of high efficiency porous supports for composite membrane preparation, polysulfone (PSf hollow fiber membranes (outer diameter 1.57 mm, inner diameter 1.12 mm were modified by air plasma using the low temperature plasma treatment pilot plant which is easily scalable to industrial level and the Piranha etch (H2O2 + H2SO4. Chemical and plasma modification affected only surface layers and did not cause PSf chemical structure change. The modifications led to surface roughness decrease, which is of great importance for further thin film composite (TFC membranes fabrication by dense selective layer coating, and also reduced water and ethylene glycol contact angle values for modified hollow fibers surface. Furthermore, the membranes surface energy increased two-fold. The Piranha mixture chemical modification did not change the membranes average pore size and gas permeance values, while air plasma treatment increased pore size 1.5-fold and also 2 order enhanced membranes surface porosity. Since membranes surface porosity increased due to air plasma treatment the modified membranes were used as efficient supports for preparation of high permeance TFC membranes by using poly[1-(trimethylsilyl-1-propyne] as an example for selective layer fabrication.

Comparison of vitrified and unvitrified Eocene woody tissues by TMAH thermochemolysis – implications for the early stages of the formation of vitrinite

Directory of Open Access Journals (Sweden)

Huggett William W

2006-10-01

Full Text Available Abstract Samples of vitrified and unvitrified Eocene woody plant tissues collected from the Fossil Forest site, Geodetic Hills, Axel Heiberg Island, have been characterized by TMAH thermochemolysis. All samples are gymnosperm-derived, are of very low maturity and all share the same post-depositional geologic history. Differences in the distributions of products observed from vitrified and unvitrified samples suggest that vitrification of woody tissue is associated with modification of the lignin C3 side chain, following loss of all or most of the carbohydrate present in the precursor woody tissues. The key driver of vitrification appears to be physical compression of the tissue following biological removal of cellulosic materials.

Effect of Nanoparticles on the Survival and Development of Vitrified Porcine GV Oocytes.

Science.gov (United States)

Li, W J; Zhou, X L; Liu, B L; Dai, J J; Song, P; Teng, Y

BACKGROUND: Some mammalian oocytes have been successfully cryopreserved by vitrification. However, the survival and developmental rate of vitrified oocytes is still low. The incorporation of nanoparticles into cryoprotectant (CPA) may improve the efficiency of vitrification by changing the properties of solutions. The toxicity of different concentrations of hydroxy apatite (HA), silica dioxide (SO 2 ), aluminum oxide (Al 2 O 3 ) and titanium dioxide (TiO 2 ) nanoparticles (20 nm in diameter) to oocytes was tested and the toxicity threshold value of each nanoparticle was determined. Porcine GV oocytes were vitrified in optimized nano-CPA, and effects of diameter and concentration of nanoparticles on the survival rate and developmental rate of porcine GV oocytes were compared. HA nanoparticles have demonstrated the least toxicity among four nanoparticles and the developmental rate of GV-stage porcine oocytes was 100% when its concentration was lower than 0.5%. By adding 0.1% HA into VS, the developmental rate of GV-stage porcine oocytes (22%) was significantly higher than other groups. The effect of vitrification in nano-CPA on oocytes was related to the concentration of HA nanoparticles rather than their size. By adding 0.05% HA nanoparticles (60nm in diameter), the developmental rate increased dramatically from 14.7% to 30.4%. Nano-cryopreservation offers a new way to improve the effect of survival and development of oocytes, but the limitation of this technology shall not be ignored.

Formation of alteration products during dissolution of vitrified ILW in a high-pH calcium-rich solution

Energy Technology Data Exchange (ETDEWEB)

Utton, C.A., E-mail: c.utton@sheffield.ac.uk [Immobilisation Science Laboratory, Department of Materials Science and Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD (United Kingdom); Hand, R.J.; Hyatt, N.C. [Immobilisation Science Laboratory, Department of Materials Science and Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD (United Kingdom); Swanton, S.W. [AMEC, B150, Thomson Avenue, Harwell Oxford, Didcot, Oxfordshire OX11 0QB (United Kingdom); Williams, S.J. [Nuclear Decommissioning Authority, NDA Harwell Office, Building 587, Curie Avenue, Harwell Oxford, Didcot OX11 0RH (United Kingdom)

2013-11-15

To simulate the possible disposition of a vitrified intermediate-level waste (ILW) in a cementitious environment within a geological disposal facility (GDF), the durability of a laboratory simulant ILW vitrified in a borosilicate glass in a saturated Ca(OH){sub 2} solution (pH ∼12.5) was measured. Both a low surface area to volume (SA/V) ratio (∼10 m{sup −1}) Materials Characterisation Center test 1 (MCC-1) and a high SA/V ratio (∼10,000 m{sup −1}) product consistency test type B (PCT-B) were used at 50 °C for up to 170 days. The formation of alteration layers and products was followed. The surfaces of the monoliths were analysed using SEM/EDX and showed the formation of magnesium-rich precipitates and distinct calcium silicate hydrate (CSH) precipitates. Cross sections showed the development of a calcium-rich alteration layer, which was observed from 14 days. The altered layer was up to 5 μm thick after 170 days and showed accumulation of zirconium, iron and magnesium and to a lesser extent aluminium, along with calcium and silicon. Based on comparison of the rate data, it is suggested that the presence of this layer may offer some protection to the underlying glass. However, the high SA/V ratio experiments showed resumed alteration after 56 days, indicating that the altered layer may not be protective in the long term (under accelerated conditions). The formation of a magnesium-containing smectite clay (likely saponite) in addition to CSH(II), a jennite-like CSH phase, were identified in the high SA/V experiment by X-ray diffraction after 170 days. These results suggest that calcium and magnesium have important roles in both the long and shorter-term durability of vitrified wastes exposed to high pH.

Chemically durable iron phosphate glasses for vitrifying sodium bearing waste (SBW) using conventional and cold crucible induction melting (CCIM) techniques

Energy Technology Data Exchange (ETDEWEB)

Kim, C.W. E-mail: cheol@umr.edu; Ray, C.S.; Zhu, D.; Day, D.E.; Gombert, D.; Aloy, A.; Mogus-Milankovic, A.; Karabulut, M

2003-11-01

A simulated sodium bearing waste (SBW) was successfully vitrified in iron phosphate glasses (IPG) at a maximum waste loading of 40 wt% using conventional and cold crucible induction melting (CCIM) techniques. No sulfate segregation or crystalline phases were detectable in the IPG when examined by SEM and XRD. The IPG wasteforms containing 40 wt% SBW satisfy current DOE requirements for aqueous chemical durability as evaluated from their bulk dissolution rate (D{sub R}), product consistency test, and vapor hydration test. The fluid IPG wasteforms can be melted at a relatively low temperature (1000 deg. C) and for short times (<6 h). These properties combined with a significantly higher waste loading, and the feasibility of CCIM melting offer considerable savings in time, energy, and cost for vitrifying the SBW stored at the Idaho National Engineering and Environmental Laboratory in iron phosphate glasses.

Role of the NAD(P)H quinone oxidoreductase NQR and the cytochrome b AIR12 in controlling superoxide generation at the plasma membrane.

Science.gov (United States)

Biniek, Catherine; Heyno, Eiri; Kruk, Jerzy; Sparla, Francesca; Trost, Paolo; Krieger-Liszkay, Anja

2017-04-01

The quinone reductase NQR and the b-type cytochrome AIR12 of the plasma membrane are important for the control of reactive oxygen species in the apoplast. AIR12 and NQR are two proteins attached to the plant plasma membrane which may be important for generating and controlling levels of reactive oxygen species in the apoplast. AIR12 (Auxin Induced in Root culture) is a single gene of Arabidopsis that codes for a mono-heme cytochrome b. The NADPH quinone oxidoreductase NQR is a two-electron-transferring flavoenzyme that contributes to the generation of O 2 •- in isolated plasma membranes. A. thaliana double knockout plants of both NQR and AIR12 generated more O 2 •- and germinated faster than the single mutant affected in AIR12. To test whether NQR and AIR12 are able to interact functionally, recombinant purified proteins were added to plasma membranes isolated from soybean hypocotyls. In vitro NADH-dependent O 2 •- production at the plasma membrane in the presence of NQR was reduced upon addition of AIR12. Electron donation from semi-reduced menadione to AIR12 was shown to take place. Biochemical analysis showed that purified plasma membrane from soybean hypocotyls or roots contained phylloquinone and menaquinone-4 as redox carriers. This is the first report on the occurrence of menaquinone-4 in eukaryotic photosynthetic organisms. We propose that NQR and AIR12 interact via the quinone, allowing an electron transfer from cytosolic NAD(P)H to apoplastic monodehydroascorbate and control thereby the level of reactive oxygen production and the redox state of the apoplast.

Production of coloured glass-ceramics from incinerator ash using thermal plasma technology.

Science.gov (United States)

Cheng, T W; Huang, M Z; Tzeng, C C; Cheng, K B; Ueng, T H

2007-08-01

Incineration is a major treatment process for municipal solid waste in Taiwan. It is estimated that over 1.5 Mt of incinerator ash are produced annually. This study proposes using thermal plasma technology to treat incinerator ash. Sintered glass-ceramics were produced using quenched vitrified slag with colouring agents added. The experimental results showed that the major crystalline phases developed in the sintered glass-ceramics were gehlenite and wollastonite, but many other secondary phases also appeared depending on the colouring agents added. The physical/mechanical properties, chemical resistance and toxicity characteristic leaching procedure of the coloured glass-ceramics were satisfactory. The glass-ceramic products obtained from incinerator ash treated with thermal plasma technology have great potential for building applications.

Analysis of Atomic Electronic Excitation in Nonequilibrium Air Plasmas

International Nuclear Information System (INIS)

He Xin; Jia Hong-Hui; Yin Hong-Wei; Zhang Hai-Liang; Chang Sheng-Li; Yang Jun-Cai; Dang Wei-Hua

2014-01-01

Electronic excitation of atoms is studied in nonequilibrium air plasmas with the electronic temperature between 8000 K and 20000 K. By using the modified Saha—Boltzmann equation, our simplified method takes into account significant radiative processes and strong self-absorption of the vacuum ultraviolet lines. Calculations are carried out at three trajectory points of the Fire II flight experiment. Good agreement with the detailed collisional-radiative model is obtained, and the performance of this method in applications to highly nonequilibrium conditions is better than Park's quasi-steady-state model and Spradian-9.0. A short discussion on the influence of optical thickness of the vacuum ultraviolet radiation is also given. It costs about 2.9 ms on the average to solve one cell of the shock layer on a low cost computer, which shows that the present method is fast and efficient. (physics of gases, plasmas, and electric discharges)

The actual practice of air cleaning in Belgian nuclear facilities

Energy Technology Data Exchange (ETDEWEB)

Goossens, W.R. [PEGO, Mol (Belgium)

1995-02-01

With 60% of its power generation from nuclear stations Belgium has 7 nuclear power stations in operation with a total capacity of 5.4 MWe. Enriched uranium is imported and converted to fuel assemblies. The actinides of reprocessed fuel are recycled as MOX fuel. A main waste conditioning operation has been performed in the PAMELA vitrifier. The actual practice of nuclear air cleaning in the Belgian PWR station DOEL-4 and in the PAMELA -vitrification plant for high level liquid waste is reviewed.

Ion Exchange Resin and Clay Vitrification by Plasma Discharges

International Nuclear Information System (INIS)

Diaz A, Laura V.; Pacheco S, Joel O.; Pacheco P, Marquidia; Monroy G, Fabiola; Emeterio H, Miguel; Ramos F, Fidel

2006-01-01

The lack of treatment of a low and intermediate level radioactive waste (LILRW) lead us to propose a vitrification process based on a plasma discharge; this technique incorporates LILRW into a matrix glass composed of ceramic clays material. The Mexican Institute of Nuclear Research (ININ), uses an ion exchange resin IRN 150 (styrene-divinilbence copolymer) in the TRIGA MARK III nuclear reactor. The principal objective of this resin is to absorb particles containing heavy metals and low-level radioactive particles. Once the IRN 150 resin filter capacity has been exceeded, it should be replaced and treated as LILRW. In this work, a transferred plasma system was realized to vitrify this resin taking advantage of its high power density, enthalpy and chemical reactivity as well as its rapid quenching and high operation temperatures. In order to characterize the morphological structure of these clay samples, Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Thermogravimetric analysis (TGA) techniques were applied before and after the plasma treatment

Cosmetic micromanipulation of vitrified-warmed cleavage stage embryos does not improve ART outcomes: An ultrastructural study of fragments.

Science.gov (United States)

Safari, Somayyeh; Khalili, Mohammad Ali; Barekati, Zeinab; Halvaei, Iman; Anvari, Morteza; Nottola, Stefania A

2017-09-01

The aim was to study the ultrastructure of cytoplasmic fragments along with the effect of cosmetic micromanipulation (CM) on the morphology and development of vitrified-warmed embryos as well as assisted reproductive technology (ART) outcomes. A total of 96 frozen embryo transfer (FET) cycles were included in this prospective randomized study. They were divided into three groups of CM (n=32), sham (n=32) and control (n=32). In the CM group, the vitrified- warmed embryos were subjected to fragments and coarse granules removal (cosmetic micromanipulation) after laser assisted zona hatching (LAH); sham group subjected only to LAH and no intervention was taken for the control group. Fragmented embryo was evaluated by transmission electron microscopy (TEM). Significant improvement was observed in the morphological parameters, such as fragmentation degrees, evenness of the blastomeres and embryo grade during the subsequent development, after applying cosmetic micromanipulation, when compared to sham or control groups (P=0.00001). However, there were no differences in the clinical outcomes amongst the three studied groups e.g. the rates of clinical, ongoing and multiple pregnancies, implantation, delivery and live birth. In fine structure view, fragments exhibited uniform cytoplasmic texture containing majority of organelles that were observed in normal blastomeres including mitochondria. In conclusion, application of cosmetic micromanipulation in low-grade vitrified-warmed embryos showed significant improvement on embryo morphology parameters; however, did not result in noticeable improvements in clinical outcomes of the patients undergoing ART program. In addition, embryo vitrification had no adverse effects on fine structure of the fragments. Copyright © 2017 Society for Biology of Reproduction & the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in Olsztyn. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Numerical modeling of heat outflux from a vitrified high level waste

International Nuclear Information System (INIS)

Aravind, Arun; Jayaraj, Aparna; Seshadri, H.; Balasubramaniyan, V.

2018-01-01

Heat generating vitrified high-level waste is initially stored in interim storage facility with adequate cooling for sufficient period of time, and then proposed to be disposed of in deep geological repositories. Heat flux from the waste form can cause thermo mechanical changes within the disposal module and also in the surrounding rock. It may change the permeability of rock fractures over a period of time. It is very essential to study the long term performance of deep geological repository to build confidence in the design and over all operation of the disposal facility. In this study a numerical model was developed to study the temperature distribution in the waste matrix and also the heat out flux to the surrounding rock matrix

Will vitrified high active reactor waste be deposited on the seabed

International Nuclear Information System (INIS)

Koksvik, R.M.

1978-01-01

The NRPB in the UK has carried out a preliminary study on the consequences of the disposal of high active waste on the ocean bed at great depths. This is reported in 'Assessment of the radiological protection aspects of disposal of high level waste on the ocean floor', by P.D. Grimswood and G.A.M. Webb (NRPB-R 48). This report is here briefly summarised and commented on. It deals with the radiological consequences to man of the erosion and corrosion of glassified (vitrified) radioactive waste, in the deep (>4000m) ocean, radionuclide migration and path ways to man. The conclusion is that considerations of radiological protection do not preclude the disposal of specially treated radioactive waste on the ocean bed. (JIW)

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

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.

Investigation on the role of air in the dynamical evolution and thermodynamic state of a laser-induced aluminium plasma by spatial- and time-resolved spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Cristoforetti, G., E-mail: gabriele.cristoforetti@cnr.i [National Institute of Optics, Research Area of National Research Council, Via G.Moruzzi, 1 - 56124 Pisa (Italy); Lorenzetti, G.; Legnaioli, S.; Palleschi, V. [Institute of Chemistry of Organometallic Compounds, Research Area of National Research Council, Via G.Moruzzi, 1 - 56124 Pisa (Italy)

2010-09-15

The amount and the spatial distribution of air atoms and ions in a laser-induced plasma in ambient air provide important information about the formation of the plasma and its successive evolution history. For this reason, in the present work, the air mixing in a laser-induced plasma in air at atmospheric pressure and its influence on its thermodynamic evolution were studied. Information about spatial distributions of atoms and ions from Al, N and O were achieved by Abel-inverted spectra in the plume. The occurrence of LTE in the plume was also assessed by the utilization of theoretical criteria, and by the analysis of experimental spectra. Aluminium atoms and ions were found to be in LTE, while nitrogen and oxygen were not because of their longer times of relaxation toward equilibrium. Nitrogen was found to be over-ionized with respect to Saha-Eggert equilibrium, indicating that the plasma is recombining. Experimental observations suggest that the concentration of air species in the plasma is larger than that of aluminium, even in the region closer to the target, where the aluminium lines are stronger. In the front part of the plume only emission lines from air species were observed. The results suggest that a Laser-Supported Detonation (LSD) regime occurs during the trailing part of the laser pulse, resulting in the strong inclusion into the plasma of air elements. In this scenario, also the thermodynamic history of the plume is affected by the predominance of air species.

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.

Evaluation of the safety of vitrified high level waste shipments from the UK to continental Europe by sea. Annex 2

International Nuclear Information System (INIS)

Lange, F.; Fett, H.J.; Hoermann, E.; Roewekamp, M.; Cheshire, R.; Elston, B.; Slawson, G.; Raffestin, D.; Schneider, T.; Armingaud, F.; Laurent, B.

2001-01-01

The return of vitrified high level waste arising from the reprocessing of spent nuclear fuel at Sellafield to continental Europe, e.g. Germany, will start around the end of the century. The shipment of the specific flasks will include transportation via the Irish Sea, the English Channel and the North Sea with ships of the Pacific Nuclear Transport Limited (PNTL) classified to the INF 3 standard. The assessment approach is to analyse the severity and the frequency of mechanical impacts, fires and explosions with the potential to affect the package. The results show that there is a high safety margin due to the special safety features of the INF 3 ships compared to conventional ships. The remaining accident probability for a trans-port of vitrified high level waste from UK to the continent is very low. No realistic severe accident scenarios that could seriously affect the flasks and could lead to a radioactivity re-lease have been identified. (author)

Photoionization capable, extreme and vacuum ultraviolet emission in developing low temperature plasmas in air

NARCIS (Netherlands)

Stephens, J.; Fierro, A.; Beeson, S.; Laity, G.; Trienekens, D.; Joshi, R.P.; Dickens, J.; Neuber, A.

2016-01-01

Experimental observation of photoionization capable extreme ultraviolet and vacuum ultraviolet emission from nanosecond timescale, developing low temperature plasmas (i.e. streamer discharges) in atmospheric air is presented. Applying short high voltage pulses enabled the observation of the onset of

Electron-Beam Produced Air Plasma: Optical and Electrical Diagnostics

Science.gov (United States)

Vidmar, Robert; Stalder, Kenneth; Seeley, Megan

2006-10-01

High energy electron impact excitation is used to stimulate optical emissions that quantify the measurement of electron beam current. A 100 keV 10-ma electron beam source is used to produce air plasma in a test cell at a pressure between 1 mTorr and 760 Torr. Optical emissions originating from the N2 2^nd positive line at 337.1 nm and the N2^+ 1^st negative line at 391.4 nm are observed. Details on calibration using signals from an isolated transmission window and a Faraday plate are discussed. Results using this technique and other electrical signal are presented.

Design and development of a low cost, high current density power supply for streamer free atmospheric pressure DBD plasma generation in air.

Science.gov (United States)

Jain, Vishal; Visani, Anand; Srinivasan, R; Agarwal, Vivek

2018-03-01

This paper presents a new power supply architecture for generating a uniform dielectric barrier discharge (DBD) plasma in air medium at atmospheric pressure. It is quite a challenge to generate atmospheric pressure uniform glow discharge plasma, especially in air. This is because air plasma needs very high voltage for initiation of discharge. If the high voltage is used along with high current density, it leads to the formation of streamers, which is undesirable for most applications like textile treatment, etc. Researchers have tried to generate high-density plasma using a RF source, nanosecond pulsed DC source, and medium frequency AC source. However, these solutions suffer from low current discharge and low efficiency due to the addition of an external resistor to control the discharge current. Moreover, they are relatively costly and bulky. This paper presents a new power supply configuration which is very compact and generates high average density (∼0.28 W/cm 2 ) uniform glow DBD plasma in air at atmospheric pressure. The efficiency is also higher as no external resistor is required to control the discharge current. An inherent feature of this topology is that it can drive higher current oscillations (∼50 A peak and 2-3 MHz frequency) into the plasma that damp out due to the plasma dissipation only. A newly proposed model has been used with experimental validation in this paper. Simulations and experimental validation of the proposed topology are included. Also, the application of the generated plasma for polymer film treatment is demonstrated.

Formation of plasma channels in air under filamentation of focused ultrashort laser pulses

International Nuclear Information System (INIS)

Ionin, A A; Seleznev, L V; Sunchugasheva, E S

2015-01-01

The formation of plasma channels in air under filamentation of focused ultrashort laser pulses was experimentally and theoretically studied together with theoreticians of the Moscow State University and the Institute of Atmospheric Optics. The influence of various characteristics of ultrashort laser pulses on these plasma channels is discussed. Plasma channels formed under filamentation of focused laser beams with a wavefront distorted by spherical aberration (introduced by adaptive optics) and by astigmatism, with cross-section spatially formed by various diaphragms and with different UV and IR wavelengths, were experimentally and numerically studied. The influence of plasma channels created by a filament of a focused UV or IR femtosecond laser pulse (λ = 248 nm or 740 nm) on characteristics of other plasma channels formed by a femtosecond pulse at the same wavelength following the first one with varied nanosecond time delay was also experimentally studied. An application of plasma channels formed due to the filamentation of focused UV ultrashort laser pulses including a train of such pulses and a combination of ultrashort and long (∼100 ns) laser pulses for triggering and guiding long (∼1 m) electric discharges is discussed. (topical review)

Effects of Atmospheric Pressure Air Plasma Pretreatment on the Seed Germination and Early Growth of Andrographis paniculata

Energy Technology Data Exchange (ETDEWEB)

Jiayun, Tong; Rui, He; Xiaoli, Zhang; Ruoting, Zhan; Weiwen, Chen [Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education, Guangzhou 510006 (China); Yang Size, E-mail: rayhe618@hotmail.com [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2014-03-01

The objective of this paper is to demonstrate whether air plasma can change the seed germination characteristics, seedling emergence, as well as biochemical reactivity, in Andrographis paniculata (A. paniculata) seedlings by modifying the seed coat and finding a beneficial treatment dose. Eight treatment doses and one control were used to conduct electrical conductivity determination, a germination test, a seedling emergence test and a biochemical assay. The results showed that after being treated with air plasma excited at 5950 V for 10 s, the permeability of the seeds was improved significantly, resulting in the acceleration of seed germination and seedling emergence. In the meantime, the catalase activity and catalase isoenzyme expression were also improved, while the malondialdehyde content in the seedlings was decreased (which means greater counteraction with environmental stress). After being treated with 4250 V for 10 s and 5950 V for 20 s, the seed germination was enhanced, but without an obvious change in seedling emergence. However, after treatment with 3400 V for 20 s and 5100 V for 10 s, the permeability of the seeds was decreased, resulting in a delay in seedling emergence. These results indicate that air plasma can change the physiological and biochemical characteristics of Andrographis paniculata seeds by modifying the seed coat, combined with the effects of the active plasma species, and that different treating doses have different effects.

Effects of Atmospheric Pressure Air Plasma Pretreatment on the Seed Germination and Early Growth of Andrographis paniculata

International Nuclear Information System (INIS)

Tong Jiayun; He Rui; Zhang Xiaoli; Zhan Ruoting; Chen Weiwen; Yang Size

2014-01-01

The objective of this paper is to demonstrate whether air plasma can change the seed germination characteristics, seedling emergence, as well as biochemical reactivity, in Andrographis paniculata (A. paniculata) seedlings by modifying the seed coat and finding a beneficial treatment dose. Eight treatment doses and one control were used to conduct electrical conductivity determination, a germination test, a seedling emergence test and a biochemical assay. The results showed that after being treated with air plasma excited at 5950 V for 10 s, the permeability of the seeds was improved significantly, resulting in the acceleration of seed germination and seedling emergence. In the meantime, the catalase activity and catalase isoenzyme expression were also improved, while the malondialdehyde content in the seedlings was decreased (which means greater counteraction with environmental stress). After being treated with 4250 V for 10 s and 5950 V for 20 s, the seed germination was enhanced, but without an obvious change in seedling emergence. However, after treatment with 3400 V for 20 s and 5100 V for 10 s, the permeability of the seeds was decreased, resulting in a delay in seedling emergence. These results indicate that air plasma can change the physiological and biochemical characteristics of Andrographis paniculata seeds by modifying the seed coat, combined with the effects of the active plasma species, and that different treating doses have different effects

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

International Nuclear Information System (INIS)

Yang Guoqing; Zhang Guanjun; Zhang Wenyuan

2011-01-01

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

Modeling of laser induced air plasma and shock wave dynamics using 2D-hydrodynamic simulations

Science.gov (United States)

Paturi, Prem Kiran; S, Sai Shiva; Chelikani, Leela; Ikkurthi, Venkata Ramana; C. D., Sijoy; Chaturvedi, Shashank; Acrhem, University Of Hyderabad Team; Computational Analysis Division, Bhabha Atomic Research Centre, Visakhapatnam Team

2017-06-01

The laser induced air plasma dynamics and the SW evolution modeled using the two dimensional hydrodynamic code by considering two different EOS: ideal gas EOS with charge state effects taken into consideration and Chemical Equilibrium applications (CEA) EOS considering the chemical kinetics of different species will be presented. The inverse bremsstrahlung absorption process due to electron-ion and electron-neutrals is considered for the laser-air interaction process for both the models. The numerical results obtained with the two models were compared with that of the experimental observations over the time scales of 200 - 4000 ns at an input laser intensity of 2.3 ×1010 W/cm2. The comparison shows that the plasma and shock dynamics differ significantly for two EOS considered. With the ideas gas EOS the asymmetric expansion and the subsequent plasma dynamics have been well reproduced as observed in the experiments, whereas with the CEA model these processes were not reproduced due to the laser energy absorption occurring mostly at the focal volume. ACRHEM team thank DRDO, India for funding.

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

DEFF Research Database (Denmark)

Fang, Lei; Hallam, David; Bermúdez, Raúl

2016-01-01

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

Investigation on Plasma Jet Flow Phenomena During DC Air Arc Motion in Bridge-Type Contacts

Science.gov (United States)

Zhai, Guofu; Bo, Kai; Chen, Mo; Zhou, Xue; Qiao, Xinlei

2016-05-01

Arc plasma jet flow in the air was investigated under a bridge-type contacts in a DC 270 V resistive circuit. We characterized the arc plasma jet flow appearance at different currents by using high-speed photography, and two polished contacts were used to search for the relationship between roughness and plasma jet flow. Then, to make the nature of arc plasma jet flow phenomena clear, a simplified model based on magnetohydrodynamic (MHD) theory was established and calculated. The simulated DC arc plasma was presented with the temperature distribution and the current density distribution. Furthermore, the calculated arc flow velocity field showed that the circular vortex was an embodiment of the arc plasma jet flow progress. The combined action of volume force and contact surface was the main reason of the arc jet flow. supported by National Natural Science Foundation of China (Nos. 51307030, 51277038)

Measurement of OH density and air-helium mixture ratio in an atmospheric-pressure helium plasma jet

International Nuclear Information System (INIS)

Yonemori, Seiya; Ono, Ryo; Nakagawa, Yusuke; Oda, Tetsuji

2012-01-01

The absolute density of OH radicals in an atmospheric-pressure helium plasma jet is measured using laser-induced fluorescence (LIF). The plasma jet is generated in room air by applying a pulsed high voltage onto a quartz tube with helium gas flow. The time-averaged OH density is 0.10 ppm near the quartz tube nozzle, decreasing away from the nozzle. OH radicals are produced from water vapour in the helium flow, which is humidified by water adsorbed on the inner surface of the helium line and the quartz tube. When helium is artificially humidified using a water bubbler, the OH density increases with humidity and reaches 2.5 ppm when the water vapour content is 200 ppm. Two-dimensional distribution of air-helium mixture ratio in the plasma jet is also measured using the decay rate of the LIF signal waveform which is determined by the quenching rate of laser-excited OH radicals. (paper)

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.

Inactivation of Staphylococcus aureus and Enterococcus faecalis by a direct-current, cold atmospheric-pressure air plasma microjet.

Science.gov (United States)

Tian, Ye; Sun, Peng; Wu, Haiyan; Bai, Na; Wang, Ruixue; Zhu, Weidong; Zhang, Jue; Liu, Fuxiang

2010-07-01

A direct-current, cold atmospheric-pressure air plasma microjet (PMJ) was performed to inactivate Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis) in air. The process of sterilization and morphology of bacteria was observed. We wish to know the possible inactivation mechanisms of PMJ and explore a potential application in dental and other temperature sensitive treatment. In this study, we employed a direct current, atmospheric pressure, cold air PMJ to inactivate bacterias. Scanning electron microscopy was employed to evaluate the morphology of S. aureus and showed rupture of cell walls after the plasma treatment and Optical emission spectrum (OES) were used to understand the possible inactivation mechanisms of PMJ. The inactivation rates could reach 100% in 5 min. When the distance between the exit nozzle of the PMJ device and Petri dish was extended from 1 cm to 3 cm, effective inactivation was also observed with a similar inactivation curve. The inactivation of bacteria is attributed to the abundant reactive oxygen and nitrogen species, as well as ultroviolet radiation in the plasma. Different life spans and defensibilities of these killing agents may hold the key to understanding the different inactivation curves at different treatment distances.

Plasma parameters in the channel of a long leader in air

International Nuclear Information System (INIS)

Aleksandrov, N.L.; Konchakov, A. M.; Bazelyan, E.M.

2001-01-01

The time evolution of the electric field in the leader channel and other characteristics of the leader plasma in long air gaps are simulated. Calculations are performed in the one-dimensional time-dependent model with allowance for the time-varying energy deposition in the channel, the channel expansion, and the nonequilibrium ionization kinetics in the leader plasma. The calculations show that, at a gas temperature of 4500-6000 K, associative ionization becomes a dominant ionization mechanism in the leader channel; as a result, the electric field decreases to 100-200 V/cm in 10 -4 -10 -3 s under the conditions typical of the leader discharge. The calculated electric field agrees well with the data from the experimental modeling of long leaders by a spark discharge in short gaps

On the improvement of signal repeatability in laser-induced air plasmas

Science.gov (United States)

Zhang, Shuai; Sheta, Sahar; Hou, Zong-Yu; Wang, Zhe

2018-04-01

The relatively low repeatability of laser-induced breakdown spectroscopy (LIBS) severely hinders its wide commercialization. In the present work, we investigate the optimization of LIBS system for repeatability improvement for both signal generation (plasma evolution) and signal collection. Timeintegrated spectra and images were obtained under different laser energies and focal lengths to investigate the optimum configuration for stable plasmas and repeatable signals. Using our experimental setup, the optimum conditions were found to be a laser energy of 250 mJ and a focus length of 100 mm. A stable and homogeneous plasma with the largest hot core area in the optimum condition yielded the most stable LIBS signal. Time-resolved images showed that the rebounding processes through the air plasma evolution caused the relative standard deviation (RSD) to increase with laser energies of > 250 mJ. In addition, the emission collection was improved by using a concave spherical mirror. The line intensities doubled as their RSDs decreased by approximately 25%. When the signal generation and collection were optimized simultaneously, the pulse-to-pulse RSDs were reduced to approximately 3% for O(I), N(I), and H(I) lines, which are better than the RSDs reported for solid samples and showed great potential for LIBS quantitative analysis by gasifying the solid or liquid samples.

Novel fragmentation model for pulverized coal particles gasification in low temperature air thermal plasma

Directory of Open Access Journals (Sweden)

Jovanović Rastko D.

2016-01-01

Full Text Available New system for start-up and flame support based on coal gasification by low temperature air thermal plasma is planned to supplement current heavy oil system in Serbian thermal power plants in order to decrease air pollutions emission and operational costs. Locally introduced plasma thermal energy heats up and ignites entrained coal particles, thus starting chain process which releases heat energy from gasified coal particles inside burner channel. Important stages during particle combustion, such as particle devolatilisation and char combustion, are described with satisfying accuracy in existing commercial CFD codes that are extensively used as powerful tool for pulverized coal combustion and gasification modeling. However, during plasma coal gasification, high plasma temperature induces strong thermal stresses inside interacting coal particles. These stresses lead to “thermal shock” and extensive particle fragmentation during which coal particles with initial size of 50-100 m disintegrate into fragments of at most 5-10 m. This intensifies volatile release by a factor 3-4 and substantially accelerates the oxidation of combustible matter. Particle fragmentation, due to its small size and thus limited influence on combustion process is commonly neglected in modelling. The main focus of this work is to suggest novel approach to pulverized coal gasification under high temperature conditions and to implement it into commercial comprehensive code ANSYS FLUENT 14.0. Proposed model was validated against experimental data obtained in newly built pilot scale D.C plasma burner test facility. Newly developed model showed very good agreement with experimental results with relative error less than 10%, while the standard built-in gasification model had error up to 25%.

Factors Analysis of Spontaneous Abortion after Thawed-vitrified Blastocysts Transfer

Institute of Scientific and Technical Information of China (English)

Dong YANG; Zheng-yi SUN; Cheng-yan DENG; Qi YU; Fang-fang HE

2008-01-01

Objective To investigate the factors resulting in spontaneous abortion after transferring frozen-thawing blastocysts. Methods A total of 108 cases transferring vitrified blastocysts were divided into two groups: abortion group (n =20) and ongoing group (n=88). Cytogenetic analysis of apoblemas was performed in 12 cases of the abortion.Results The overall spontaneous abortion rate was 18.50%(20/108) and the early spontaneous rate was 16.67%(18/108). ,4 significant difference in maternal age was observed (abortion group: 33.3±4.0 years, ongoing group: 31.0±3.6 years, P=0.02). No difference in other parameters was found. Cytogenetic analysis of apoblemas was obtained for 12 cases, and 2 specimens were contaminated. Seven of ten patients had abnormal karyotypes. Conclusion The underlying cause of spontaneous abortion after transferring frozen thawing blastocysts appears to be abnormal karyotypes.Advancing maternal age seems to increase the risk of spontaneous abortion.

Comparative study of the expansion dynamics of laser-driven plasma and shock wave in in-air and underwater ablation regimes

Science.gov (United States)

Nguyen, Thao T. P.; Tanabe, Rie; Ito, Yoshiro

2018-03-01

We compared the expansion characteristics of the plasma plumes and shock waves generated in laser-induced shock process between the two ablation regimes: in air and under water. The observation was made from the initial moment when the laser pulse hit the target until 1.5 μs. The shock processes were driven by focusing a single laser pulse (1064 nm, FWHM = 13 ns) onto the surface of epoxy-resin blocks using a 40-mm focal length lens. The estimated laser intensity at the target plane is approximate to 9 ×109Wcm-2 . We used the fast-imaging technique to observe the expansion of the plasma plume and a custom-designed time-resolved photoelasticity imaging technique to observe the propagation of shock waves with the time resolution of nanoseconds. We found that at the same intensity of the laser beam, the plasma expansion during the laser pulse follows different mechanisms: the plasma plume that grows in air follows a radiation-wave model while a detonation-wave model can explain the expansion of the plasma plume induced in water. The ideal blast wave theory can be used to predict the decay of the shock wave in air but is not appropriate to describe the decay of the shock wave induced under water.

Atmospheric pressure He-air plasma jet: Breakdown process and propagation phenomenon

International Nuclear Information System (INIS)

Begum, Asma; Laroussi, Mounir; Pervez, Mohammad Rasel

2013-01-01

In this paper He-discharge (plasma jet/bullet) in atmospheric pressure air and its progression phenomenon has been studied experimentally using ICCD camera, optical emission spectroscopy (OES) and calibrated dielectric probe measurements. The repetitive nanosecond pulse has applied to a plasma pencil to generate discharge in the helium gas channel. The discharge propagation speed was measured from the ICCD images. The axial electric field distribution in the plasma jet is inferred from the optical emission spectroscopic data and from the probe measurement. The correlation between the jet velocities, jet length with the pulse duration is established. It shows that the plasma jet is not isolated from the input voltage along its propagation path. The discharge propagation speed, the electron density and the local and average electric field distribution along the plasma jet axis predicted from the experimental results are in good agreement with the data predicted by numerical simulation of the streamer propagation presented in different literatures. The ionization phenomenon of the discharge predicts the key ionization parameters, such as speed, peak electric field in the front, and electron density. The maximum local electric field measured by OES is 95 kV/cm at 1.3 cm of the jet axis, and average EF measured by probe is 24 kV/cm at the same place of the jet. The average and local electron density estimated are in the order of 10 11 cm -3 and it reaches to the maximum of 10 12 cm -3 .

Developmental Competence of Vitrified-Warmed Bovine Oocytes at the Germinal-Vesicle Stage is Improved by Cyclic Adenosine Monophosphate Modulators during In Vitro Maturation.

Directory of Open Access Journals (Sweden)

Kenji Ezoe

Full Text Available Cryopreservation of mature oocytes and embryos has provided numerous benefits in reproductive medicine. Although successful cryopreservation of germinal-vesicle stage (GV oocytes holds promise for further advances in reproductive biology and clinical embryology fields, reports regarding cryopreservation of immature oocytes are limited. Oocyte survival and maturation rates have improved since vitrification is being performed at the GV stage, but the subsequent developmental competence of GV oocytes is still low. The purpose of this study was to evaluate the effects of supplementation of the maturation medium with cyclic adenosine monophosphate (cAMP modulators on the developmental competence of vitrified-warmed GV bovine oocytes. GV oocytes were vitrified-warmed and cultured to allow for oocyte maturation, and then parthenogenetically activated or fertilized in vitro. Our results indicate that addition of a cAMP modulator forskolin (FSK or 3-isobutyl-1-methylxanthine (IBMX to the maturation medium significantly improved the developmental competence of vitrified-warmed GV oocytes. We also demonstrated that vitrification of GV oocytes led to a decline in cAMP levels and maturation-promoting factor (MPF activity in the oocytes during the initial and final phases of maturation, respectively. Nevertheless, the addition of FSK or IBMX to the maturation medium significantly elevated cAMP levels and MPF activity during IVM. Taken together, our results suggest that the cryopreservation-associated meiotic and developmental abnormalities observed in GV oocytes may be ameliorated by an artificial increase in cAMP levels during maturation culture after warming.

Dry storage technologies: Optimized solutions for spent fuels and vitrified residues

International Nuclear Information System (INIS)

Roland, Vincent; Verdier, Antoine; Sicard, Damien; Neider, Tara

2006-01-01

ancillary equipment, Ready to move to final or centralized repository or reprocessing facility or other ISFSI, Compact systems, Easy rearrangement, Easy handling; - In favor of concrete shielded canisters based systems: Economics when initial quantity is sufficient to spread out up front equipment investment significant cost - Shielding advantage, Easy local production of the relatively light canisters. Both approaches of dry storage technologies can have a positive impact on their public acceptance because of their non-permanent characteristics and because their transport license refers to internationally recognized rules, standards and methods. Currently, more than 1,000 COGEMA Logistics/Transnuclear Inc. dry storage systems have been ordered in Belgium, Germany, Japan, Switzerland, Armenia and the US. Because of the evolution of burnup of spent fuel to be reprocessed, the high activity vitrified residues cannot be transported in the existing cask designs presently used. Therefore, COGEMA LOGISTICS has decided in the late nineties to develop a brand new design of casks with optimized capacity able to store and transport the most active and hottest canisters: the TN TM 81 casks currently in use in Switzerland and the TN TM 85 cask which shall permit in the near future in Germany the storage and the transport of the most active vitrified residues. The TN TM 81 and the TN TM 85 casks have been designed to fully anticipate shipment constraints of the present vitrified residue production in existing reprocessing facilities. They also used the feedback of current shipments and the operational constraints and experience of receiving and shipping facilities. The casks had to fit as much as possible in the existing procedures for the already existing casks such as the TN TM 28 cask and TS 28 V cask, all along the logistics chain of loading, unloading, transport and maintenance. In addition, years of feedback and experience in design and operations - together with ever improved

Advanced separation and transmutation, long dated behavior of vitrified wastes: 15 years of scientific researches; Separation poussee et transmutation, comportement a long terme des dechets vitrifies: 15 ans d'avancees scientifiques

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-02-15

This report presents the results after 15 years of researches at the Cea, concerning the separation and transmutation of radioactive wastes and the conditioning and the long time storage of wastes at the surface. These researches were asked in the framework of the Bataille law. The first part devoted to the transmutation and separation of ling life radioactive elements presents the challenges, the advanced separation, the transmutation and the evaluation of the researches. The second part devoted to the long dated storage discusses the high activity wastes vitrification, the behavior of the vitrified wastes packages after thousand years, the international researches and the evaluation of the researches. (A.L.B.)

Silent Discharge Plasma Technology for the Treatment of Air Toxics and Other Applications

Energy Technology Data Exchange (ETDEWEB)

Rosocha, Louis A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chase, Peter J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gross, Michael P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

1998-09-21

Under this CRADA, the Los Alamos National Laboratory (LANL) and High Mesa Technologies, Inc. (HMT) carried out a joint project on the development of the silent discharge plasma (SDP) technology for the treatment of hazardous air pollutants and other hazardous or toxic chemicals. The project had two major components: a technology-demonstration part and a scale-up and commercialization part. In the first part, a small-scale, mobile SDP plasma processor, which was being developed under a CRADA with the Electric Power Research Institute (EPRI) was the mobile equipment was modified for higher capacity service and employed for an innovative remediation technologies demonstration on soil-vapor extraction off-gases at the McClellan Air Force Base near Sacramento, CA. The performance of the SDP system for the variety of volatile organic compounds (VOCs) encountered at the McClellan site was sufficiently promising to the project HMT and LANL worked together to formulate a scale-up strategy and commercialization/manufacturing plan, and to design a prototype scaled-up SDP unit. HMT and LANL are now in the final stages of completing a licensing agreement for the technology and HMT is in the process of raising funds to engineer and manufacture commercial prototype SDP equipment focused on stack-gas emissions control and environmental remediation. HMT, in collaboration with another Northern New Mexico business, Coyote Aerospace, has also been successful in receiving a Phase I Small Business Innovative Research (SBIR) award from the Army Research Office to develop, design, and construct a small non-thermal plasma reactor for laboratory studies ("Non-Thermal Plasma Reactor for Control of Fugitive Emissions of Toxic Gases")

Screening of a dust particle charge in a humid air plasma created by an electron beam

Science.gov (United States)

Filippov, A. V.; Derbenev, I. N.; Kurkin, S. A.

2018-01-01

A kinetic model has been developed for charged particle reactions in a humid air plasma produced by a fast electron beam. The model includes over 550 reactions with electrons, 33 positive ion species and 14 negative ion species. The model has been tested by solving 48 non-steady state equations for number densities of charged particles in humid air electron beam plasma, and by comparing with the available experimental data. The system of 48 steady state equations has been solved by iterative method in order to define the main ion species of the humid air plasma. A reduced kinetic model has been developed to describe the processes with the main ions and electrons. Screening constants have been calculated on the basis of the reduced system by means of Leverrier-Fadeev method. The dependencies of screening constants on gas ionization rates have been found for the rates from 10 to 1018 cm-3s-1 and the fraction of water molecules from 0 to 2%. The analysis of the constants has revealed that one of them is close to the inverse Debye length, and the other constants are defined by the inverse diffusion lengths passed by ions in the characteristic times of the attachment, recombination, and ion conversion. Pure imaginary screening constants appear at low rates of gas ionization.

Air plasma spray processing and electrochemical characterization of Cu-SDC coatings for use in solid oxide fuel cell anodes

Energy Technology Data Exchange (ETDEWEB)

Benoved, Nir [Department of Mechanical Engineering, The University of British Columbia, 2054-6250 Applied Sciences Lane, Vancouver, British Columbia (Canada); Kesler, O. [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario (Canada)

2009-09-05

Air plasma spraying has been used to produce porous composite anodes based on Ce{sub 0.8}Sm{sub 0.2}O{sub 1.9} (SDC) and Cu for use in solid oxide fuel cells (SOFCs). Preliminarily, a range of plasma conditions has been examined for the production of composite coatings from pre-mixed SDC and CuO powders. Plasma gas compositions were varied to obtain a range of plasma temperatures. After reduction in H{sub 2}, coatings were characterized for composition and microstructure using EDX and SEM. As a result of these tests, symmetrical sintered electrolyte-supported anode-anode cells were fabricated by air plasma spraying of the anodes, followed by in situ reduction of the CuO to Cu. Full cells deposited on SS430 porous substrates were then produced in one integrated process. Fine CuO and SDC powders have been used to produce homogeneously mixed anode coatings with higher surface area microstructures, resulting in area-specific polarization resistances of 4.8 {omega} cm{sup 2} in impedance tests in hydrogen at 712 C. (author)

Air plasma spray processing and electrochemical characterization of Cu-SDC coatings for use in solid oxide fuel cell anodes

Science.gov (United States)

Benoved, Nir; Kesler, O.

Air plasma spraying has been used to produce porous composite anodes based on Ce 0.8Sm 0.2O 1.9 (SDC) and Cu for use in solid oxide fuel cells (SOFCs). Preliminarily, a range of plasma conditions has been examined for the production of composite coatings from pre-mixed SDC and CuO powders. Plasma gas compositions were varied to obtain a range of plasma temperatures. After reduction in H 2, coatings were characterized for composition and microstructure using EDX and SEM. As a result of these tests, symmetrical sintered electrolyte-supported anode-anode cells were fabricated by air plasma spraying of the anodes, followed by in situ reduction of the CuO to Cu. Full cells deposited on SS430 porous substrates were then produced in one integrated process. Fine CuO and SDC powders have been used to produce homogeneously mixed anode coatings with higher surface area microstructures, resulting in area-specific polarization resistances of 4.8 Ω cm 2 in impedance tests in hydrogen at 712 °C.

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

Science.gov (United States)

Ganguly, Biswa

2009-10-01

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

Study on THz wave generation from air plasma induced by quasi-square Airy beam

Science.gov (United States)

Zhang, Shijing; Zhang, Liangliang; Jiang, Guangtong; Zhang, Cunlin; Zhao, Yuejin

2018-01-01

Terahertz (THz) wave has attracted considerable attention in recent years because of its potential applications. The intense THz waves generated from air plasma induced by two-color femtosecond laser are widely used due to its high generation efficiency and broad frequency bandwidth. The parameters of the laser change the distribution of the air plasma, and then affect the generation of THz wave. In this research, we investigate the THz wave generation from air plasma induced by quasi-square Airy beam. Unlike the common Gauss beam, the quasi-square Airy beam has ability to autofocus and to increase the maximum intensity at the focus. By using the spatial light modulator (SLM), we can change the parameters of phase map to control the shape of the Airy beam. We obtain the two-color laser field by a 100-um-thick BBO crystal, then use a Golay detector to record THz wave energy. By comparing terahertz generation at different modulation depths, we find that terahertz energy produced by quasi-square Airy beam is up to 3.1 times stronger than that of Gauss beam with identical laser energy. In order to understand the influence of quasi-square Airy beam on the BBO crystal, we record THz wave energy by changing the azimuthal angle of BBO crystal with Gauss beam and Airy beam at different modulation depths. We find that the trend of terahertz energy with respect to the azimuthal angle of the BBO crystal keeps the same for different laser beams. We believe that the quasi-square Airy beam or other auto focusing beam can significantly improve the efficiency of terahertz wave generation and pave the way for its applications.

Inactivation of Staphylococcus aureus and Enterococcus faecalis by a direct-current, cold atmospheric-pressure air plasma microjet☆

Science.gov (United States)

Tian, Ye; Sun, Peng; Wu, Haiyan; Bai, Na; Wang, Ruixue; Zhu, Weidong; Zhang, Jue; Liu, Fuxiang

2010-01-01

Objective A direct-current, cold atmospheric-pressure air plasma microjet (PMJ) was performed to inactivate Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis) in air. The process of sterilization and morphology of bacteria was observed. We wish to know the possible inactivation mechanisms of PMJ and explore a potential application in dental and other temperature sensitive treatment. Methods In this study, we employed a direct current, atmospheric pressure, cold air PMJ to inactivate bacterias. Scanning electron microscopy was employed to evaluate the morphology of S. aureus and showed rupture of cell walls after the plasma treatment and Optical emission spectrum (OES) were used to understand the possible inactivation mechanisms of PMJ. Results The inactivation rates could reach 100% in 5 min. When the distance between the exit nozzle of the PMJ device and Petri dish was extended from 1 cm to 3 cm, effective inactivation was also observed with a similar inactivation curve. Conclusion The inactivation of bacteria is attributed to the abundant reactive oxygen and nitrogen species, as well as ultroviolet radiation in the plasma. Different life spans and defensibilities of these killing agents may hold the key to understanding the different inactivation curves at different treatment distances. PMID:23554639

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)

High capacity cask (TN28V) and International Transport System for the return shipment of vitrified high activity wastes

International Nuclear Information System (INIS)

Sert, G.; Savornin, B.; Rouquette, Y.

1989-01-01

The reprocessing of spent fuel generates different kinds of wastes. Among them fission products and non fissile actinides represent 98% of the radioactivity; these wastes are separated, concentrated, mixed with molten glass and poured into stainless steel containers. For political reasons, it is necessary to return these vitrified high activity wastes to the foreign countries which have decided to have their spent fuel reprocessed in France. So the transport of vitrified waste is vital for both the reprocessor and the utilities that have trusted the reprocessor and this operation has to be securely performed to give satisfaction to all concerned particles. For that reason Cogema will control the whole transport activity from La Hague plants to the receiving facilities of the customers. Therefore cogema will be responsible of the transport whatever the cask type (transport or storage) and will subcontract the transport operation to experienced companies such as Transnucleaire, PNTL or NTL, who will act on behalf of Cogema. Cogema will be the owner of the transport casks while the storage casks will normally be owned by the customers. Both cask types will of course have to comply with the requirements of La Hague, as published by Cogema

Formation of secondary phases during the corrosion of vitrified nuclear waste

International Nuclear Information System (INIS)

Zimmer, P.

2003-11-01

The first aim of this work was the examination of the formation and long-term stability of secondary phases that form during an aquatic attack on simulated, vitrified nuclear waste. In the glasses used for the investigations actinides had been replaced by rare earth elements (chemical analogues), other radionuclides by inactive isotopes. For predictions about the long-term safety of nuclear waste disposals it is important to identify secondary phases that have formed during the glass corrosion process and to determine their stability. Two different saline solutions (rich in MgCl 2 and in NaCl, respectively) are relevant as a corrosion medium for waste disposals. It showed that in such an environment sulfates, silicates and molybdates represent the main new formations of minerals after 7.5 years of corrosion. However, the formation, long-term stability and sorption characteristics of those minerals regarding rare earth elements depend to a high degree on the corrosion medium as well as on changes in the geochemical environment in the course of the experiment. By means of SEM/EDX barytes of different morphology with up to 15% w/w Sr ((Ba,Sr)SO 4 ) were identified in both corrosion media; they were capable of binding long-term stable radionuclides like Sr. Furthermore, pure rare earth (RE) sulfates were observed in the saline solution rich in MgCl 2 . This formation of RE-sulfates has not been described in the literature so far. Depending on the saline solution, the secondary silicate and molybdate minerals that formed on the glass surfaces differed noticeably in their sorption characteristics and their stability. Another focus of the work was a more profound understanding of the glass corrosion mechanism in the presence of metallic iron since steel jackets are used as technical barriers for the vitrified nuclear waste in nuclear waste disposals. Another important point in connection with the mobilization and immobilization of radionuclides released during glass

Application of microwave air plasma in the destruction of trichloroethylene and carbon tetrachloride at atmospheric pressure

Energy Technology Data Exchange (ETDEWEB)

Rubio, S.J., E-mail: f62rugas@uco.es [Departamento de Fisica, Campus de Rabanales, Edificio Einstein, Planta Baja, Universidad de Cordoba (Spain); Quintero, M.C.; Rodero, A. [Departamento de Fisica, Campus de Rabanales, Edificio Einstein, Planta Baja, Universidad de Cordoba (Spain)

2011-02-15

In this study, the destruction rate of a volatile waste destruction system based on a microwave plasma torch operating at atmospheric pressure was investigated. Atmospheric air was used to maintain the plasma and was introduced by a compressor, which resulted in lower operating costs compared to other gases such as argon and helium. To isolate the output gases and control the plasma discharge atmosphere, the plasma was coupled to a reactor. The effect of the gas flow rate, microwave power and initial concentration of compound on the destruction efficiency of the system was evaluated. In this study, trichloroethylene and carbon tetrachloride were used as representative volatile organic compounds to determine the destruction rate of the system. Based on the experimental results, at an applied microwave power less than 1000 W, the proposed system can reduce input concentrations in the ppmv range to output concentrations at the ppbv level. High air flow rates and initial concentrations produced energy efficiency values greater than 1000 g/kW h. The output gases and species present in the plasma were analysed by gas chromatography and optical emission spectroscopy, respectively, and negligible amounts of halogenated compounds resulting from the cleavage of C{sub 2}HCl{sub 3} and CCl{sub 4} were observed. The gaseous byproducts of decomposition consisted mainly of CO{sub 2}, NO and N{sub 2}O, as well as trace amounts of Cl{sub 2} and solid CuCl.

Application of microwave air plasma in the destruction of trichloroethylene and carbon tetrachloride at atmospheric pressure.

Science.gov (United States)

Rubio, S J; Quintero, M C; Rodero, A

2011-02-15

In this study, the destruction rate of a volatile waste destruction system based on a microwave plasma torch operating at atmospheric pressure was investigated. Atmospheric air was used to maintain the plasma and was introduced by a compressor, which resulted in lower operating costs compared to other gases such as argon and helium. To isolate the output gases and control the plasma discharge atmosphere, the plasma was coupled to a reactor. The effect of the gas flow rate, microwave power and initial concentration of compound on the destruction efficiency of the system was evaluated. In this study, trichloroethylene and carbon tetrachloride were used as representative volatile organic compounds to determine the destruction rate of the system. Based on the experimental results, at an applied microwave power less than 1000 W, the proposed system can reduce input concentrations in the ppmv range to output concentrations at the ppbv level. High air flow rates and initial concentrations produced energy efficiency values greater than 1000 g/kW h. The output gases and species present in the plasma were analysed by gas chromatography and optical emission spectroscopy, respectively, and negligible amounts of halogenated compounds resulting from the cleavage of C(2)HCl(3) and CCl(4) were observed. The gaseous byproducts of decomposition consisted mainly of CO(2), NO and N(2)O, as well as trace amounts of Cl(2) and solid CuCl. Copyright © 2010 Elsevier B.V. All rights reserved.

Atmospheric pressure He-air plasma jet: Breakdown process and propagation phenomenon

Energy Technology Data Exchange (ETDEWEB)

Begum, Asma [Independent University, Bangladesh, School of Engineering and Computer Science, Bashundhara, Dhaka (Bangladesh); Laroussi, Mounir [Old Dominion University, Department of Electrical and Computer Engineering, Norfolk, Virginia (United States); Pervez, Mohammad Rasel [Master Mind College, Department of Physics, Dhanmondi, Dhaka (Bangladesh)

2013-06-15

In this paper He-discharge (plasma jet/bullet) in atmospheric pressure air and its progression phenomenon has been studied experimentally using ICCD camera, optical emission spectroscopy (OES) and calibrated dielectric probe measurements. The repetitive nanosecond pulse has applied to a plasma pencil to generate discharge in the helium gas channel. The discharge propagation speed was measured from the ICCD images. The axial electric field distribution in the plasma jet is inferred from the optical emission spectroscopic data and from the probe measurement. The correlation between the jet velocities, jet length with the pulse duration is established. It shows that the plasma jet is not isolated from the input voltage along its propagation path. The discharge propagation speed, the electron density and the local and average electric field distribution along the plasma jet axis predicted from the experimental results are in good agreement with the data predicted by numerical simulation of the streamer propagation presented in different literatures. The ionization phenomenon of the discharge predicts the key ionization parameters, such as speed, peak electric field in the front, and electron density. The maximum local electric field measured by OES is 95 kV/cm at 1.3 cm of the jet axis, and average EF measured by probe is 24 kV/cm at the same place of the jet. The average and local electron density estimated are in the order of 10{sup 11} cm{sup -3} and it reaches to the maximum of 10{sup 12} cm{sup -3}.

Low and intermediate level radioactive waste processing in plasma reactor

International Nuclear Information System (INIS)

Sauchyn, V.; Khvedchyn, I.; Van Oost, G.

2013-01-01

Methods of low and intermediate level radioactive waste processing comprise: cementation, bituminization, curing in polymer matrices, combustion and pyrolysis. All these methods are limited in their application in the field of chemical, morphological, and aggregate composition of material to be processed. The thermal plasma method is one of the universal methods of RAW processing. The use of electric-arc plasma with mean temperatures 2000 - 8000 K can effectively carry out the destruction of organic compounds into atoms and ions with very high speeds and high degree of conversion. Destruction of complex substances without oxygen leads to a decrease of the volume of exhaust gases and dimension of gas cleaning system. This paper presents the plasma reactor for thermal processing of low and intermediate level radioactive waste of mixed morphology. The equipment realizes plasma-pyrolytic conversion of wastes and results in a conditioned product in a single stage. As a result, the volume of conditioned waste is significantly reduced (more than 10 times). Waste is converted into an environmentally friendly form that suits long-term storage. The leaching rate of macro-components from the vitrified compound is less than 1.10 -7 g/(cm 2 .day). (authors)

Modeling of plasma chemistry in a corona streamer pulse series in air

International Nuclear Information System (INIS)

Nowakowska, H.; Stanco, J.; Dors, M.; Mizeraczyk, J.

2002-01-01

The aim of this study is to analyse the chemistry in air treated by a series of corona discharge streamers. Attention is focused on the conversion of ozone and nitrogen oxides. In the model it is assumed that the streamer head of relatively small geometrical dimensions propagates from the anode to the cathode, leaving the streamer channel behind. Any elemental gas volume in the streamer path is subjected first to the conditions of the streamer head, and next to those of the streamer channel. The kinetics of plasma-chemical processes occurring in the gas is modeled numerically for a single streamer and a series of streamers. The temporal evolution of 25 chemical compounds initially present or produced in air is calculated. (author)

Interferometric investigation of shock waves induced by a TEA-CO2 laser produced plasma in air in front of a solid target

International Nuclear Information System (INIS)

Apostol, D.; Apostol, I.; Cojocaru, E.; Draganescu, V.; Mihailescu, N.I.; Morjan, I.; Konov, I.V.

1979-06-01

The shock waves induced in the surrounding atmosphere by an air plasma were investigated by laser interferometry. The air breakdown plasma was produced by a TEA-CO 2 laser in front of a solid target. The results were compared to the predictions of theory of intense explosions in gases and a good agreement was inferred. It was also determined that the symmetry of the expansion of the initial shock wave is determined by the plasma source shape and, accordingly, depends on the laser power density incident on the target surface. However, for further stages all the shock waves expand spherically. (author)

The potential use of transmission tomography techniques for the quality checking of cement encapsulated and vitrified wastes

International Nuclear Information System (INIS)

Huddleston, J.; Hutchinson, I.G.; Burch, S.F.; Perring, J.K.

1989-01-01

The technique of extracting information from real-time radiographic images and processing that data using tomographic reconstruction methods has been demonstrated using simulated full-sized specimens of encapsulated intermediate level waste and high level vitrified waste. Sections of these objects are produced perpendicular to the plane of the radiographs from which they originate. The resulting section is clearer and more informative than the radiographs for complex specimens. The technique is proposed as a complementary stage to existing radiographic analyses. (author)

Apparent Surface Free Energy of Polymer/Paper Composite Material Treated by Air Plasma

Directory of Open Access Journals (Sweden)

Konrad Terpiłowski

2017-01-01

Full Text Available Surface plasma treatment consists in changes of surface properties without changing internal properties. In this paper composite polymer/paper material is used for production of packaging in cosmetic industry. There are problems with bonding this material at the time of packaging production due to its properties. Composite surface was treated by air plasma for 1, 10, 20, and 30 s. The advancing and receding contact angles of water, formamide, and diiodomethane were measured using both treated and untreated samples. Apparent surface free energy was estimated using the hysteresis (CAH and Van Oss, Good, Chaudhury approaches (LWAB. Surface roughness was investigated using optical profilometry and identification of after plasma treatment emerging chemical groups was made by means of the XPS (X-ray photoelectron spectroscopy technique. After plasma treatment the values of contact angles decreased which is particularly evident for polar liquids. Apparent surface free energy increased compared to that of untreated samples. Changes of energy value are due to the electron-donor parameter of energy. This parameter increases as a result of adding polar groups at the time of surface plasma activation. Changes of surface properties are combination of increase of polar chemical functional groups, increase on the surface, and surface roughness increase.

Analysis of Surface Leaching Processes in Vitrified High-Level Nuclear Wastes Using In-Situ Raman Imaging and Atomistic Modeling - Final Report

International Nuclear Information System (INIS)

Simmons, Joseph H.

2001-01-01

The in situ analysis of surface conditions of vitrified nuclear wastes can provide an important check of the burial status of radioactive objects without risk of radiation exposure. Raman spectroscopy was initially chosen as the most promising method for testing the surface conditions of glasses undergoing chemical corrosion, and was used extensively during the first year. However, it was determined that infrared reflection spectroscopy was better suited to this particular need and was used for the remaining two years to investigate the surface corrosion behavior of model silicate glasses for extension to nuclear waste glasses. The developed methodology is consistent with the known theory of optical propagation of dielectric media and uses the Kramers-Kronig formalism. The results show that it is possible to study the corrosion of glass by analyzing the glass surface using reflection fast Fourier infrared measurements and the newly developed ''dispersion analysis method.'' The data show how this analysis can be used to monitor the corrosion behavior of vitrified waste glasses over extended periods of storage

Kinetic study on non-thermal volumetric plasma decay in the early afterglow of air discharge generated by a short pulse microwave or laser

Energy Technology Data Exchange (ETDEWEB)

Yang, Wei, E-mail: yangwei861212@126.com; Zhou, Qianhong; Dong, Zhiwei [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)

2016-08-28

This paper reports a kinetic study on non-thermal plasma decay in the early afterglow of air discharge generated by short pulse microwave or laser. A global self-consistent model is based on the particle balance of complex plasma chemistry, electron energy equation, and gas thermal balance equation. Electron-ion Coulomb collision is included in the steady state Boltzmann equation solver to accurately describe the electron mobility and other transport coefficients. The model is used to simulate the afterglow of microsecond to nanosecond pulse microwave discharge in N{sub 2}, O{sub 2}, and air, as well as femtosecond laser filament discharge in dry and humid air. The simulated results for electron density decay are in quantitative agreement with the available measured ones. The evolution of plasma decay under an external electric field is also investigated, and the effect of gas heating is considered. The underlying mechanism of plasma density decay is unveiled through the above kinetic modeling.

The conceptual design of high temporal resolution HCN interferometry for atmospheric pressure air plasmas

Science.gov (United States)

Zhang, J. B.; Liu, H. Q.; Jie, Y. X.; Wei, X. C.; Hu, L. Q.

2018-01-01

A heterodyne interferometer operating at the frequency f = 890 GHz has been designed for measuring the electron density of atmospheric pressure air plasmas, it's density range is from 1015 to 3×1019 m-3 and the pressure range is from 1 Pa to 20 kPa. The system is configured as a Mach\

Improved Ethanol Production from Xylose by Candida shehatae Induced by Dielectric Barrier Discharge Air Plasma

International Nuclear Information System (INIS)

Chen Huixia; Xiu Zhilong; Bai Fengwu

2014-01-01

Xylose fermentation is essential for ethanol production from lignocellulosic biomass. Exposure of the xylose-fermenting yeast Candida shehatae (C. shehatae) CICC1766 to atmospheric pressure dielectric barrier discharge (DBD) air plasma yields a clone (designated as C81015) with stability, which exhibits a higher ethanol fermentation rate from xylose, giving a maximal enhancement in ethanol production of 36.2% compared to the control (untreated). However, the biomass production of C81015 is lower than that of the control. Analysis of the NADH (nicotinamide adenine dinucleotide)- and NADPH (nicotinamide adenine dinucleotide phosphate)-linked xylose reductases and NAD + -linked xylitol dehydrogenase indicates that their activities are enhanced by 34.1%, 61.5% and 66.3%, respectively, suggesting that the activities of these three enzymes are responsible for improving ethanol fermentation in C81015 with xylose as a substrate. The results of this study show that DBD air plasma could serve as a novel and effective means of generating microbial strains that can better use xylose for ethanol fermentation

Improved Ethanol Production from Xylose by Candida shehatae Induced by Dielectric Barrier Discharge Air Plasma

Science.gov (United States)

Chen, Huixia; Xiu, Zhilong; Bai, Fengwu

2014-06-01

Xylose fermentation is essential for ethanol production from lignocellulosic biomass. Exposure of the xylose-fermenting yeast Candida shehatae (C. shehatae) CICC1766 to atmospheric pressure dielectric barrier discharge (DBD) air plasma yields a clone (designated as C81015) with stability, which exhibits a higher ethanol fermentation rate from xylose, giving a maximal enhancement in ethanol production of 36.2% compared to the control (untreated). However, the biomass production of C81015 is lower than that of the control. Analysis of the NADH (nicotinamide adenine dinucleotide)- and NADPH (nicotinamide adenine dinucleotide phosphate)-linked xylose reductases and NAD+-linked xylitol dehydrogenase indicates that their activities are enhanced by 34.1%, 61.5% and 66.3%, respectively, suggesting that the activities of these three enzymes are responsible for improving ethanol fermentation in C81015 with xylose as a substrate. The results of this study show that DBD air plasma could serve as a novel and effective means of generating microbial strains that can better use xylose for ethanol fermentation.

Investigation of flame structure in plasma-assisted turbulent premixed methane-air flame

Science.gov (United States)

Hualei, ZHANG; Liming, HE; Jinlu, YU; Wentao, QI; Gaocheng, CHEN

2018-02-01

The mechanism of plasma-assisted combustion at increasing discharge voltage is investigated in detail at two distinctive system schemes (pretreatment of reactants and direct in situ discharge). OH-planar laser-induced fluorescence (PLIF) technique is used to diagnose the turbulent structure methane-air flame, and the experimental apparatus consists of dump burner, plasma-generating system, gas supply system and OH-PLIF system. Results have shown that the effect of pretreatment of reactants on flame can be categorized into three regimes: regime I for voltage lower than 6.6 kV; regime II for voltage between 6.6 and 11.1 kV; and regime III for voltage between 11.1 and 12.5 kV. In regime I, aerodynamic effect and slower oxidation of higher hydrocarbons generated around the inner electrode tip plays a dominate role, while in regime III, the temperature rising effect will probably superimpose on the chemical effect and amplify it. For wire-cylinder dielectric barrier discharge reactor with spatially uneven electric field, the amount of radicals and hydrocarbons are decreased monotonically in radial direction which affects the flame shape. With regard to in situ plasma discharge in flames, the discharge pattern changes from streamer type to glow type. Compared with the case of reactants pretreatment, the flame propagates further in the upstream direction. In the discharge region, the OH intensity is highest for in situ plasma assisted combustion, indicating that the plasma energy is coupled into flame reaction zone.

Electromagnetic radiation emitted by a plasma produced in air by laser pulses with lambda = 10.6 μm

International Nuclear Information System (INIS)

Danilychev, V.A.; Zvorykin, V.D.; Kholin, I.V.; Chugunov, A.Y.

1981-01-01

The spectrum, brightness, and energy have been measured for the electromagnetic radiation emitted by a plasma produced in air near a solid surface by pulses from a high-power CO 2 laser. The air pressure was varied over the range p 0 = 0.1--760 torr, and the laser power density was varied over the range q = 5 x 10 6 --10 8 W/cm 2 . At p 0 > or approx. =2--5 torr the radiation properties of the plasma are determined by a laser-beam absorption wave which arises in the gas. The maximum brightness temperature, T/sub b/approx. =50 000 K (lambda = 400 +- 20 nm), is reached at p 0 = 25 torr. The emission spectrum is quite different from an equilibrium spectrum, consisting primarily of NII, OII, and NIII lines. The total energy radiation by the plasma in the wavelength interval 360--2600 nm into a solid angle of 4π sr reaches 2.3% of the laser pulse energy

Size-dependent mechanical properties of PVA nanofibers reduced via air plasma treatment

International Nuclear Information System (INIS)

Fu Qiang; Song Xuefeng; Gao Jingyun; Han Xiaobing; Zhao Qing; Yu Dapeng; Jin Yu; Jiang Xingyu

2010-01-01

Organic nanowires/fibers have great potential in applications such as organic electronics and soft electronic techniques. Therefore investigation of their mechanical performance is of importance. The Young's modulus of poly(vinyl alcohol) (PVA) nanofibers was analyzed by scanning probe microscopy (SPM) methods. Air plasma treatment was used to reduce the nanofibers to different sizes. Size-dependent mechanical properties of PVA nanofibers were studied and revealed that the Young's modulus increased dramatically when the scales became very small (<80 nm).

Size-dependent mechanical properties of PVA nanofibers reduced via air plasma treatment.

Science.gov (United States)

Fu, Qiang; Jin, Yu; Song, Xuefeng; Gao, Jingyun; Han, Xiaobing; Jiang, Xingyu; Zhao, Qing; Yu, Dapeng

2010-03-05

Organic nanowires/fibers have great potential in applications such as organic electronics and soft electronic techniques. Therefore investigation of their mechanical performance is of importance. The Young's modulus of poly(vinyl alcohol) (PVA) nanofibers was analyzed by scanning probe microscopy (SPM) methods. Air plasma treatment was used to reduce the nanofibers to different sizes. Size-dependent mechanical properties of PVA nanofibers were studied and revealed that the Young's modulus increased dramatically when the scales became very small (<80 nm).

Sintered glass ceramic composites from vitrified municipal solid waste bottom ashes

International Nuclear Information System (INIS)

Aloisi, Mirko; Karamanov, Alexander; Taglieri, Giuliana; Ferrante, Fabiola; Pelino, Mario

2006-01-01

A glass ceramic composite was obtained by sinter-crystallisation of vitrified municipal solid waste bottom ashes with the addition of various percentages of alumina waste. The sintering was investigated by differential dilatometry and the crystallisation of the glass particles by differential thermal analysis. The crystalline phases produced by the thermal treatment were identified by X-ray diffraction analysis. The sintering process was found to be affected by the alumina addition and inhibited by the beginning of the crystal-phase precipitation. Scanning electron microscopy was performed on the fractured sintered samples to observe the effect of the sintering. Young's modulus and the mechanical strength of the sintered glass ceramic and composites were determined at different heating rates. The application of high heating rate and the addition of alumina powder improved the mechanical properties. Compared to the sintered glass ceramic without additives, the bending strength and the Young's modulus obtained at 20 deg. C/min, increased by about 20% and 30%, respectively

Long time storage containers for spent fuels and vitrified wastes: synthesis of the studies

International Nuclear Information System (INIS)

Beziat, A.

2004-01-01

This report presents a synthesis of the studies relatives to the containers devoted to the long time spent fuels storage and vitrified wastes packages. These studies were realized in the framework of the axis 3 of the law of 1991 on the radioactive wastes management. The first part is devoted to the presentation of the studies. The container sizing studies which constitute the first containment barrier are then presented. The material choice and the closed system are also detailed. The studies were validate by the realization of containers models and an associated demonstration program is proposed. A synthesis of the technical and economical studies allowed to determine the components and operation costs. (A.L.B.)

A concept for a station for the encapsulation of vitrified highly radioactive waste into containers for final disposal

International Nuclear Information System (INIS)

Anon

1984-09-01

The report presents a concept and plans for a station for the encapsulation of vitrified highly radioactive waste into containers for final disposal. The process steps, the layout of the station, the main components of equipment and the sequence of operations under normal conditions are described. The station is designed for vitrified waste from reprocessing. The volume of the waste packages is 150 l, and each package contains the equivalent of 1.33 tonne HM of fuel. The radionuclide activity of the waste corresponds to spent fuel with a decay time of 40 years from discharge from the reactor. It is assumed that after transport under normal conditions the steel shell enclosing the waste is gastight and its surface is free of contamination. The containers for final disposal are made of cast steel and have the form of hollow cylinders with hemispherical ends; their overall length is 2 m and their overall diameter 0.94 m. The station is so designed that the whole procedure, from supply of the transport containers containing the waste to the delivery of the full final disposal containers, is carried out by remote control behind radiation screens in an area isolated from the environment. Containers that do not fulfill the quality control requirements can be improved or repaired in a special rework cell without interfering with the further normal operation of the plant. (author)

DC graphite plasma arc melter technology for waste vitrification

International Nuclear Information System (INIS)

Hamilton, R.A.; Wittle, J.K.; Trescot, J.; Wilver, P.

1995-01-01

This paper describes the features and benefits of a DC Arc Melter for the permanent treatment of all types of solid wastes including nonhazardous, hazardous and radioactive. This DC Arc Melter system is the low cost permanent solution for solid waste pollution prevention and remediation. Concern over the effective disposal of wastes generated by our industrial society, worldwide, has prompted development of technologies to address the problem. The only solution that has the ability to process almost all wastes, and to recover/recycle metallic and inorganic matter, is the group of technologies known as melters. Melters have distinct advantages over traditional technologies such as incineration because melters; operate at higher temperatures, are relatively unaffected by changes in the waste stream, produce a vitrified stable product, reduce gaseous emissions, and have the capability to recover/recycle slag, metals and gas. The system, DC Plasma Arc Melter, has the lowest capital, maintenance and operating cost of any melter technology because of its patented DC Plasma Arc with graphite electrode. DC Plasma Arc Melter systems are available in sizes from 50 kg/batch or 250-3,000 kg/hr on a continuous basis

Measurement of cytoplasmic Ca2+ concentration in Saccharomyces cerevisiae induced by air cold plasma

Science.gov (United States)

Xiaoyu, DONG

2018-03-01

In this study, a novel approach to measure the absolute cytoplasmic Ca2+ concentration ([Ca2+]cyt) using the Ca2+ indicator fluo-3 AM was established. The parameters associated with the probe fluo-3 AM were optimized to accurately determine fluorescence intensity from the Ca2+-bound probe. Using three optimized parameters (final concentration of 6 mM probe, incubation time of 135 min, loading probe before plasma treatment), the maximum fluorescence intensity (F max = 527.8 a.u.) and the minimum fluorescence intensity (F min = 63.8 a.u.) were obtained in a saturated Ca2+ solution or a solution of lacking Ca2+. Correspondingly, the maximum [Ca2+]cyt induced by cold plasma was 1232.5 nM. Therefore, the Ca2+ indicator fluo-3 AM was successfully applied to measure the absolute [Ca2+]cyt in Saccharomyces cerevisiae stimulated by cold plasma at atmospheric air pressure.

Comments on a paper tilted 'The sea transport of vitrified high-level radioactive wastes: Unresolved safety issues'

International Nuclear Information System (INIS)

Sprung, J.L.; McConnell, P.E.; Nigrey, P.J.; Ammerman, D.J.

1997-05-01

The cited paper estimates the consequences that might occur should a purpose-built ship transporting Vitrified High Level Waste (VHLW) be involved in a severe collision that causes the VHLW canisters in one Type-B package to spill onto the floor of a major ocean fishing region. Release of radioactivity from VHLW glass logs, failure of elastomer cask seals, failure of VHLW canisters due to stress corrosion cracking (SCC), and the probabilities of the hypothesized accident scenario, of catastrophic cask failure, and of cask recovery from the sea are all discussed

On non-equilibrium atmospheric pressure plasma jets and plasma bullet

Science.gov (United States)

Lu, Xinpei

2012-10-01

Because of the enhanced plasma chemistry, atmospheric pressure nonequilibrium plasmas (APNPs) have been widely studied for several emerging applications such as biomedical applications. For the biomedical applications, plasma jet devices, which generate plasma in open space (surrounding air) rather than in confined discharge gaps only, have lots of advantages over the traditional dielectric barrier discharge (DBD) devices. For example, it can be used for root canal disinfection, which can't be realized by the traditional plasma device. On the other hand, currently, the working gases of most of the plasma jet devices are noble gases or the mixtures of the noble gases with small amount of O2, or air. If ambient air is used as the working gas, several serious difficulties are encountered in the plasma generation process. Amongst these are high gas temperatures and disrupting instabilities. In this presentation, firstly, a brief review of the different cold plasma jets developed to date is presented. Secondly, several different plasma jet devices developed in our lab are reported. The effects of various parameters on the plasma jets are discussed. Finally, one of the most interesting phenomena of APNP-Js, the plasma bullet is discussed and its behavior is described. References: [1] X. Lu, M. Laroussi, V. Puech, Plasma Sources Sci. Technol. 21, 034005 (2012); [2] Y. Xian, X. Lu, S. Wu, P. Chu, and Y. Pan, Appl. Phys. Lett. 100, 123702 (2012); [3] X. Pei, X. Lu, J. Liu, D. Liu, Y. Yang, K. Ostrikov, P. Chu, and Y. Pan, J. Phys. D 45, 165205 (2012).

Microparticle charging in dry air plasma created by an external ionization source

International Nuclear Information System (INIS)

Derbenev, I N; Filippov, A V

2015-01-01

In the present paper the dust particle charging is studied in a dry air plasma created by an external ionization source. The ionization rate is changed in the range 10 1 -10 20 cm -3 s -1 . It is found that the main positive ion of the plasma is O + 4 and the main negative ones are O − 2 and O − 4 . The point sink model based on the diffusion-drift approach shows that the screening potential distribution around a dust particle is a superposition of four Debye-like exponentials with four different spatial scales. The first scale almost coincides with the Debye radius. The second one is the distance, passed by positive and negative plasma components due to ambipolar diffusion in their recombination time. The third one is defined by the negative ion conversion and diffusion. The fourth scale is described by the electron attachment, recombination and diffusion at low gas ionization rates and by the recombination and diffusion of negative diatomic ions at high ionization rates. It is also shown that the electron flux defines the microparticle charge at high ionization rates, whereas the electron number density is much less than the ion one. (paper)

The Mutation Breeding and Mutagenic Effect of Air Plasma on Penicillium Chrysogenum

International Nuclear Information System (INIS)

Gui Fang; Wang Hui; Wang Peng; Liu Hui; Yuan Chengling; Zheng Zhiming; Cai Xiaochun; Hu Yihua

2012-01-01

Low temperature air plasma was used as the mutation tool for penicillin-producing strain Penicillium chrysogenum. The discharge conditions were RF power of 360 W, temperature of 40°C in a sealed chamber, and pressure of 10 Pa to 30 Pa. The result showed that the kinetics of the survival rate followed a typical saddle-shaped curve. Based on a statistic analysis, at the treating duration of 10 min, the positive mutation rate was as high as 37.5% while the negative mutation rate was low. The colonial morphology changed obviously when the plasma treating duration reached or exceeded 45 min. After both primary and secondary screening, a mutant designated as aPc051310 with high productivity of penicillin was obtained, and a strong mutagenic effect on P. chrysogenum was observed in the process. It was proved that after five generations, the mutant aPc051310 still exhibits a high productivity. All the results prove that the plasma mutation method could be developed as a convenient and effective tool to breed high-yield strains in the fermentation industry, while expanding the plasm application at the same time.

Long-term leaching behavior of vitrified high-level wastes

International Nuclear Information System (INIS)

Ishiguro, Katsuhiko; Sonobe, Hitoshi; Sasaki, Noriaki; Kashihara, Hidechiyo

1985-01-01

A long-term Soxhlet leaching test, long-term static leaching test, solubility evaluation test and actual-scale glass solid leaching test were carried out for simulated vitrified wastes. Under high flow-rate leachate conditions, the leaching of high-solubility substances such as B and Na increases almost linearly with time while that of Fe, Ni and rare earth metals strongly depends on their solubility. The overall leaching rate changes (tends to decrease) with time under static conditions. The elution or diffusion is the rate determining step in the earlier region of the leaching process while the solubilities of major components have greater effects in the latter region. The change of the dominant leaching mechanism is delayed more largely as the surface-area to leachate-volume (SA/V) ratio decreases. Actual-scale glass specimens showed almost the same leaching behaviors as small-scale ones. If cracks exist in glass solid, the leaching in them is slow causing little effects on the overall leaching rate. This may be due to the fact that solubility-dependent leaching is occuring in the cracks. The long-term static leaching observations were not satisfactorily explained by the MCC-3 type solubility test results. It is important to clarify the solubility-dependent leaching behaviors at large SA/V ratios. (Nogami, K.)

Kinetics of NO formation and decay in nanosecond pulse discharges in Air, H2-Air, and C2H4-Air mixtures

International Nuclear Information System (INIS)

Burnette, David; Shkurenkov, Ivan; Adamovich, Igor V; Lempert, Walter R

2016-01-01

Time-resolved, absolute NO and N atom number densities are measured by NO Laser Induced Fluorescence (LIF) and N Two-Photon Absorption LIF in a diffuse plasma filament, nanosecond pulse discharge in dry air, hydrogen-air, and ethylene-air mixtures at 40 Torr, over a wide range of equivalence ratios. The results are compared with kinetic modeling calculations incorporating pulsed discharge dynamics, kinetics of vibrationally and electronically excited states of nitrogen, plasma chemical reactions, and radial transport. The results show that in air afterglow, NO decay occurs primarily by the reaction with N atoms, NO  +  N  →  N 2   +  O. In the presence of hydrogen, this reaction is mitigated by reaction of N atoms with OH, N  +  OH  →  NO  +  H, resulting in significant reduction of N atom number density in the afterglow, additional NO production, and considerably higher NO number densities. In fuel-lean ethylene-air mixtures, a similar trend (i.e. N atom concentration reduction and NO number density increase) is observed, although [NO] increase on ms time scale is not as pronounced as in H 2 -air mixtures. In near-stoichiometric and fuel-lean ethylene-air mixtures, when N atom number density was below detection limit, NO concentration was measured to be lower than in air plasma. These results suggest that NO kinetics in hydrocarbon-air plasmas is more complex compared to air and hydrogen-air plasmas, additional NO reaction pathways may well be possible, and their analysis requires further kinetic modeling calculations. (paper)

DC plasma arc melter technology for waste vitrification

International Nuclear Information System (INIS)

Hamilton, R.A.; Wittle, J.K.; Trescot, J.

1995-01-01

This paper describes the features and benefits of a breakthrough DC Arc Melter for the permanent treatment of all types of solid wastes including nonhazardous, hazardous and radioactive. This DC Arc Furnace system, now commercially available, is the low cost permanent solution for solid waste pollution prevention and remediation. Concern over the effective disposal of wastes generated by the industrial society, worldwide, has prompted development of technologies to address the problem. For the most part these technologies have resulted in niche solutions with limited application. The only solution that has the ability to process almost all wastes, and to recover/recycle metallic and inorganic matter, is the group of technologies known as melters. Melters have distinct advantages over traditional technologies such as incineration because melters operate at higher temperatures, are relatively unaffected by changes in the waste stream, produce a vitrified stable product, and have the capability to recover/recycle slag, metals and gas. The system, DC Plasma Arc Melter, has the lowest capital, maintenance and operating cost of any melter technology because of its patented DC Plasma Arc with graphite electrode. DC Plasma Arc Melter systems are commercially available in sizes from 50 kg/batch or 250--3,000 kg/hr on a continuous feed basis. This paper examines the design and operating benefits of a DC Plasma Arc Melter System

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)

Plasma-catalytic reforming of ethanol: influence of air activation rate and reforming temperature

International Nuclear Information System (INIS)

Nedybaliuk, O.A.; Chernyak, V.Ya.; Fedirchuk, I.I.; Demchina, V.P.; Bortyshevsky, V.A.; Korzh, R.V.

2016-01-01

This paper presents the study of the influence that air activation rate and reforming temperature have on the gaseous products composition and conversion efficiency during the plasma-catalytic reforming of ethanol. The analysis of product composition showed that the conversion efficiency of ethanol has a maximum in the studied range of reforming temperatures. Researched system provided high reforming efficiency and high hydrogen energy yield at the lower temperatures than traditional conversion technologies

Loading, transport and storage of casks of the type CASTOR registered HAW28M in the frame of vitrified high-level waste repatriation from France

International Nuclear Information System (INIS)

Horn, Thomas; Graf, Wilhelm; Gosch-Warning, Michaela

2011-01-01

Until 2005 the German nuclear power plant operators have contracts with AREVA NC (former COGEMA) and NDA (former BNFL) concerning the reprocessing of spent fuel elements. The reprocessed and vitrified radioactive waste has to be repatriated to Germany. Due to the reprocessing of spent fuel elements with increased burnup and the repatriation after shorter cooling time the total activity and the Cm-244 content of the high-level-waste coquilles have increased since 2008. Consequently the heat output has increased to 2 kW/coquille. Therefore the new transport cask type CASTOR registered HAW28M was developed. The authors describe the design of the casks, the licensing according to the German transport regulations, loading procedures, radiation measurements and shipment completion. In autumn 2011 the repatriation of vitrified high-level waste from France is supposed to be completed with the transport of eleven CASTOR registered HAW28M.

Verification of Vitrified High-Activity Waste Stored in a CASTOR HAW 20/28 CG Cask by Simulated Baseline Comparison

International Nuclear Information System (INIS)

Shephard, A.; Arenas-Carrasco, J.; Dratschmidt, H.; De-Baere, P.; Af Ekenstam, G.; Lebrun, A.

2010-01-01

The verification process for the vitrification of high-activity waste (HAW) focuses on maintaining the continuity-of-knowledge of special nuclear material (SNM) as it traverses a vitrification facility. However, the inaccessible nature of a vitrification facility presents an obstacle to the deployment of conventional safeguards, albeit the process area of a vitrification facility is effectively a hot cell. The employment of remotely operated NDA hardware/DA sample equipment inside the process area would be problematic-at-best and the alternative of continuous monitoring would draw heavily on the critical resource of inspector time. In response to the aforementioned constraints, the IAEA and Euratom opted to develop a new method which focuses on the verification of SNM after the vitrified HAW has been sealed in storage casks. The new method verifies the presence of the vitrified HAW through the comparison of total neutron count rates collected at points around a cask with those predicted by Monte Carlo simulation. The model includes a dual N50 neutron slab detector (custom design by Euratom) and a CASTOR HAW 20/28 CG storage cask configured with the operator declared contents. By comparison of the simulated neutron emission pattern and field measurements, the displacement of Pu and U is evident from a detectable neutron signal defect. Because the spontaneous fission of 244 Cm is the dominant neutron source in vitrified HAW, the 244 Cm/Pu and 244 Cm/U mass ratios must be known in order to relate the neutron signal outside the cask to the amounts of Pu and U stored inside. These mass ratios can be determined from HAW samples collected by the inspectorates from the accountability tanks and analyzed by DA. The absence of separation of SNM from the HAW is verified by other measures. To ensure the validity of the simulation, sources of uncertainty were systematically addressed and quantified. This new verification method effectively removes the need for NDA equipment

Modeling of electron behaviors under microwave electric field in methane and air pre-mixture gas plasma assisted combustion

Science.gov (United States)

Akashi, Haruaki; Sasaki, K.; Yoshinaga, T.

2011-10-01

Recently, plasma-assisted combustion has been focused on for achieving more efficient combustion way of fossil fuels, reducing pollutants and so on. Shinohara et al has reported that the flame length of methane and air premixed burner shortened by irradiating microwave power without increase of gas temperature. This suggests that electrons heated by microwave electric field assist the combustion. They also measured emission from 2nd Positive Band System (2nd PBS) of nitrogen during the irradiation. To clarify this mechanism, electron behavior under microwave power should be examined. To obtain electron transport parameters, electron Monte Carlo simulations in methane and air mixture gas have been done. A simple model has been developed to simulate inside the flame. To make this model simple, some assumptions are made. The electrons diffuse from the combustion plasma region. And the electrons quickly reach their equilibrium state. And it is found that the simulated emission from 2nd PBS agrees with the experimental result. Recently, plasma-assisted combustion has been focused on for achieving more efficient combustion way of fossil fuels, reducing pollutants and so on. Shinohara et al has reported that the flame length of methane and air premixed burner shortened by irradiating microwave power without increase of gas temperature. This suggests that electrons heated by microwave electric field assist the combustion. They also measured emission from 2nd Positive Band System (2nd PBS) of nitrogen during the irradiation. To clarify this mechanism, electron behavior under microwave power should be examined. To obtain electron transport parameters, electron Monte Carlo simulations in methane and air mixture gas have been done. A simple model has been developed to simulate inside the flame. To make this model simple, some assumptions are made. The electrons diffuse from the combustion plasma region. And the electrons quickly reach their equilibrium state. And it is found

A Review and Analysis of European Industrial Experience in Handling LWR Spent Fuel and Vitrified High-Level Waste

Energy Technology Data Exchange (ETDEWEB)

Blomeke, J.O.

2001-07-10

The industrial facilities that have been built or are under construction in France, the United Kingdom, Sweden, and West Germany to handle light-water reactor (LWR) spent fuel and canisters of vitrified high-level waste before ultimate disposal are described and illustrated with drawings and photographs. Published information on the operating performance of these facilities is also given. This information was assembled for consideration in planning and design of similar equipment and facilities needed for the Federal Waste Management System in the United States.

Treatment of airborne asbestos and asbestos-like microfiber particles using atmospheric microwave air plasma

Energy Technology Data Exchange (ETDEWEB)

Averroes, A., E-mail: aulia.a.aa@m.titech.ac.jp [Department of Chemical Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); Sekiguchi, H. [Department of Chemical Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); Sakamoto, K. [Street Design Corporation, 6-9-30 Shimo odanaka, Kawasaki-shi, Kanagawa 211-0041 (Japan)

2011-11-15

Highlights: {yields} We use atmospheric microwave air plasma to treat ceramic fiber and stainless fiber as asbestos alike micro fiber particle. {yields} Spheroidization of certain type of ceramic fiber and stainless fiber particle. {yields} The evaluation of the treated particles by the fiber vanishing rate. {yields} Good fiber vanishing rate is observed for fiber particle with diameter below 10 {mu}m. {yields} The treatment of pure asbestos and a suggestion of the use of this method for the treatment airborne asbestos. - Abstract: Atmospheric microwave air plasma was used to treat asbestos-like microfiber particles that had two types of ceramic fiber and one type of stainless fiber. The treated particles were characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). The experiment results showed that one type of ceramic fiber (Alumina:Silica = 1:1) and the stainless fiber were spheroidized, but the other type of ceramic fiber (Alumina:Silica = 7:3) was not. The conversion of the fibers was investigated by calculating the equivalent diameter, the aspect ratio, and the fiber content ratio. The fiber content ratio in various conditions showed values near zero. The relationship between the normalized fiber vanishing rate and the energy needed to melt the particles completely per unit surface area of projected particles, which is defined as {eta}, was examined and seen to indicate that the normalized fiber vanishing rate decreased rapidly with the increase in {eta}. Finally, some preliminary experiments for pure asbestos were conducted, and the analysis via XRD and phase-contrast microscopy (PCM) showed the availability of the plasma treatment.

Treatment of airborne asbestos and asbestos-like microfiber particles using atmospheric microwave air plasma

International Nuclear Information System (INIS)

Averroes, A.; Sekiguchi, H.; Sakamoto, K.

2011-01-01

Highlights: → We use atmospheric microwave air plasma to treat ceramic fiber and stainless fiber as asbestos alike micro fiber particle. → Spheroidization of certain type of ceramic fiber and stainless fiber particle. → The evaluation of the treated particles by the fiber vanishing rate. → Good fiber vanishing rate is observed for fiber particle with diameter below 10 μm. → The treatment of pure asbestos and a suggestion of the use of this method for the treatment airborne asbestos. - Abstract: Atmospheric microwave air plasma was used to treat asbestos-like microfiber particles that had two types of ceramic fiber and one type of stainless fiber. The treated particles were characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). The experiment results showed that one type of ceramic fiber (Alumina:Silica = 1:1) and the stainless fiber were spheroidized, but the other type of ceramic fiber (Alumina:Silica = 7:3) was not. The conversion of the fibers was investigated by calculating the equivalent diameter, the aspect ratio, and the fiber content ratio. The fiber content ratio in various conditions showed values near zero. The relationship between the normalized fiber vanishing rate and the energy needed to melt the particles completely per unit surface area of projected particles, which is defined as η, was examined and seen to indicate that the normalized fiber vanishing rate decreased rapidly with the increase in η. Finally, some preliminary experiments for pure asbestos were conducted, and the analysis via XRD and phase-contrast microscopy (PCM) showed the availability of the plasma treatment.

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

International Nuclear Information System (INIS)

Fang, Z; Qiu, Y; Kuffel, E

2004-01-01

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

Field characterization plan for the 216-U-8 vitrified clay pipeline

International Nuclear Information System (INIS)

Rowley, C.A.

1994-01-01

The 216-U-8 Crib was constructed in 1952 and received waste from 1952 to 1960 as described in Appendix A. This description of work details the field activities associated with the characterization of the vitrified clay pipe (VCP) delivery line to the 216-U-8 Crib and subsurface soil sampling along the pipe route in the 200 West Area of Hanford U Plant. It will serves as a field guide for those performing the work. Soil sampling locations will be determined by a combination of radiological surface surveys and internal camera surveys of the VCP line. Depending on the condition of the pipeline and field conditions, the objectives are as follows: examine the internal condition of the VCP with a survey camera to the extent allowed by field conditions; determine precise location and depth of the VCP; document VCP integrity; document gamma radiation profile through the VCP; and correlate any relationships between surface contamination zones at grade above the VCP to identify breaches in the pipe integrity

Influence of water content on the inactivation of P. digitatum spores using an air-water plasma jet

Science.gov (United States)

Youyi, HU; Weidong, ZHU; Kun, LIU; Leng, HAN; Zhenfeng, ZHENG; Huimin, HU

2018-04-01

In order to investigate whether an air-water plasma jet is beneficial to improve the efficiency of inactivation, a series of experiments were done using a ring-needle plasma jet. The water content in the working gas (air) was accurately measured based on the Karl Fischer method. The effects of water on the production of OH (A2Σ+-X2Πi) and O (3p5P-3s5S) were also studied by optical emission spectroscopy. The results show that the water content is in the range of 2.53-9.58 mg l-1, depending on the gas/water mixture ratio. The production of OH (A2Σ+-X2Πi) rises with the increase of water content, whereas the O (3p5P-3s5S) shows a declining tendency with higher water content. The sterilization experiments indicate that this air-water plasma jet inactivates the P. digitatum spores very effectively and its efficiency rises with the increase of the water content. It is possible that OH (A2Σ+-X2Πi) is a more effective species in inactivation than O (3p5P-3s5S) and the water content benefit the spore germination inhibition through rising the OH (A2Σ+-X2Πi) production. The maximum of the inactivation efficacy is up to 93% when the applied voltage is -6.75 kV and the water content is 9.58 mg l-1.

Spatial properties of a terahertz beam generated from a two-color air plasma

DEFF Research Database (Denmark)

Pedersen, Pernille Klarskov; Wang, Tianwu; Buron, Jonas Christian Due

2013-01-01

We present a spatial characterization of terahertz (THz) beams generated from a two-color air plasma under different conditions by measuring full 3D beam profiles using a commercial THz camera. We compare two THz beam profiles emitted from plasmas generated by 35 fs and 100 fs laser pulses...... that this reduces the beam waist, and that the beam spot shape changes from Lorentzian to Gaussian. Finally, we observe a forward-propagating Gaussian THz beam by spatially filtering away the conical off-axis radiation with a 1 cm aperture......., and show that the spatial properties of the two THz beams do not change significantly. For the THz beam profile generated by the 35 fs pulse, the spatial effect of eliminating the lower frequencies is investigated by implementing two crossed polarizers working as a high-pass filter. We show...

Evaluation of the safety of vitrified high level waste shipments from UK to continental Europe by sea

International Nuclear Information System (INIS)

Lange, F.; Fett, H.; Hormann, E.; Rowekamp, M.; Elston, B.; Slawson, G.; Cheshire, R.; Schneider, T.; Raffestin, D.

1998-10-01

This document, prepared in the framework of a study for the European Commission in collaboration with the GRS (Germany and BNFL (United Kingdom), relates to the evaluation of the safety associated to the maritime transport of vitrified wastes from the United Kingdom towards Europe. With this intention, a travel of 1000 nautical miles (1852 km) was considered and a detailed analysis of the boat used by BNFL has been realized in order to elaborate a fault tree, for scenarios able to generate mechanical and thermal stresses significant on the transport packages (type B-packages). (A.L.B.)

Calculation of the net emission coefficient of an air thermal plasma at very high pressure

International Nuclear Information System (INIS)

Billoux, T; Cressault, Y; Teulet, Ph; Gleizes, A

2012-01-01

The aim of this paper is to present an accurate evaluation of the phenomena appearing for high pressure air plasmas supposed to be in local thermodynamic equilibrium (LTE). In the past, we already calculated the net emission coefficient for air mixtures at atmospheric pressure and for temperatures up to 30kK (molecular contribution being restricted to 10kK). Unfortunately, the existence of high pressures does not allow us to use this database due to the non-ideality of the plasma (Viriel and Debye corrections, energy cut-off ...), and due to the significant shifts of molecular reactions towards upper temperatures. Consequently, this paper proposes an improvement of our previous works with a consideration of high pressure corrections in the composition algorithm in order to take into account the pressure effects, and with a new calculation of all the contributions of the plasma radiation (atomic lines and continuum, molecular continuum, and molecular bands) using an updated database. A particular attention is paid to calculate the contribution of all the major molecular band systems to the radiation: O 2 (Schumann–Runge), N 2 (VUV, 1st and 2nd positive), NO (IR, β, γ, δ, element of ) and N 2 + (1st negative and Meinel). The discrete atomic lines and molecular bands radiation including the overlapping are calculated by a line-by-line method up to 30kK and 100 bar. This updated database is validated in the case of optically thin plasmas and pressure of 1bar by the comparison of our integrated emission strength with the published results. Finally, this work shows the necessity to extend the molecular radiation database up to 15kK at high pressure (bands and continuum) since their corresponding contributions could not be neglected at high temperature.

Vitrification of human pronuclear oocytes by direct plunging into cooling agent: Non sterile liquid nitrogen vs. sterile liquid air.

Science.gov (United States)

Isachenko, Vladimir; Todorov, Plamen; Seisenbayeva, Akerke; Toishibekov, Yerzhan; Isachenko, Evgenia; Rahimi, Gohar; Mallmann, Peter; Foth, Dolores; Merzenich, Markus

2018-02-01

In fact, a full sterilization of commercially-produced liquid nitrogen contaminated with different pathogens is not possible. The aim of this study was to compare the viability of human pronuclear oocytes subjected to cooling by direct submerging of open carrier in liquid nitrogen versus submerging in clean liquid air (aseptic system). One- and three-pronuclei stage embryos (n = 444) were cryopreserved by direct plunging into liquid nitrogen (vitrified) in ethylene glycol (15%), dimethylsulphoxide (15%) and 0.2M sucrose. Oocytes were exposed in 20, 33, 50 and 100% vitrification solution for 2, 1 and 1 min, and 30-50 s, respectively at room temperature. Then first part of oocytes (n = 225) were directly plunged into liquid nitrogen, and second part of oocytes (n = 219) into liquid air. Oocytes were thawed rapidly at a speed of 20,000 °C/min and then subsequently were placed into a graded series of sucrose solutions (0.5, 0.25, 0.12 and 0.06M) at 2.5 min intervals and cultured in vitro for 3 days. In both groups, the rate of high-quality embryos (Grade 6A: 6 blastomeres, no fragmentation; Grade 8A: 8 blastomeres, no fragmentation; Grade 8A compacting: 8 blastomeres, beginning of compacting) was noted. The rates of high-quality embryos developed from one-pronuclear oocytes vitrified by cooling in liquid nitrogen and liquid air were: 39.4% ± 0.6 and 38.7% ± 0.8, respectively (P > 0.1). These rates for three-pronuclear oocytes were: 45.8 ± 0.8% and 52.0 ± 0.7%, respectively (P liquid air (aseptic system) is a good alternative for using of not sterile liquid nitrogen. Copyright © 2017. Published by Elsevier Inc.

Parameters of the plasma of a dc pulsating discharge in a supersonic air flow

Energy Technology Data Exchange (ETDEWEB)

Shibkov, V. M., E-mail: shibkov@phys.msu.ru; Shibkova, L. V.; Logunov, A. A. [Moscow State University, Faculty of Physics (Russian Federation)

2017-03-15

A dc discharge in a cold (T = 200 K) supersonic air flow at a static pressure of 200–400 Torr was studied experimentally. The excited unsteady pulsating discharge has the form of a thin plasma channel with a diameter of ≤1 mm, stretched downstream the flow. Depending on the discharge current, the pulsation frequency varies from 800 to 1600 Hz and the electron temperature varies from 8000 to 15000 K.

Ozone and dinitrogen monoxide production in atmospheric pressure air dielectric barrier discharge plasma effluent generated by nanosecond pulse superimposed alternating current voltage

Science.gov (United States)

Takashima, Keisuke; Kaneko, Toshiro

2017-06-01

The effects of nanosecond pulse superposition to alternating current voltage (NS + AC) on the generation of an air dielectric barrier discharge (DBD) plasma and reactive species are experimentally studied, along with measurements of ozone (O3) and dinitrogen monoxide (N2O) in the exhausted gas through the air DBD plasma (air plasma effluent). The charge-voltage cycle measurement indicates that the role of nanosecond pulse superposition is to induce electrical charge transport and excess charge accumulation on the dielectric surface following the nanosecond pulses. The densities of O3 and N2O in NS + AC DBD are found to be significantly increased in the plasma effluent, compared to the sum of those densities generated in NS DBD and AC DBD operated individually. The production of O3 and N2O is modulated significantly by the phase in which the nanosecond pulse is superimposed. The density increase and modulation effects by the nanosecond pulse are found to correspond with the electrical charge transport and the excess electrical charge accumulation induced by the nanosecond pulse. It is suggested that the electrical charge transport by the nanosecond pulse might result in the enhancement of the nanosecond pulse current, which may lead to more efficient molecular dissociation, and the excess electrical charge accumulation induced by the nanosecond pulse increases the discharge coupling power which would enhance molecular dissociation.

Study of surface atmospheric pressure glow discharge plasma based on ultrathin laminated electrodes in air

Science.gov (United States)

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

2018-05-01

A method to generate large-area surface plasma in air by micro-discharge is proposed. Two ultrathin laminated electrode structures of non-insulating and insulating types were formed by using the nanoscale ITO conductive layer. The surface glow discharge in atmospheric air is realized in low discharge voltage by constructing the special electric field of two-dimensional unidirectional attenuation. In particular, the insulating electrode structure can avoid the loss of ITO electrodes so that the discharge stability can be increased, and the treated objects can be prevented from metal ion pollution caused by the electrode in the discharge. It has broad application prospects in the fields of aerodynamics and material surface treatment.

Report on the joint USA-Germany drop test program for a vitrified high level waste cask

International Nuclear Information System (INIS)

Golliher, K.G.; Witt, C.R.; Wieser, K.E.

1993-01-01

A series of full-scale drop tests was performed on a ductile iron transport cask in a cooperative program between the US Department of Energy (DOE) and Bundesantalt fuer Materialpruefung (BAM) in Germany. The tests, which were performed at BAM's test facility located near Lehre, Germany, were performed on a prototype cask designed for transport of Vitrified High Level Waste (VHLW) canisters. The VHLW cask is a right circular cylinder with a diameter of 1156 mm and a height of 3454 cm, and weighs approximately 24.6 kg including its payload of a single VHLW canister. The drop tests were performed with a non-radioactive, prototype VHLW canister in the cavity. (J.P.N.)

Electron energy distribution functions and transport coefficients relevant for air plasmas in the troposphere: impact of humidity and gas temperature

Energy Technology Data Exchange (ETDEWEB)

Gordillo-Vazquez, F J [Instituto de Astrofisica de Andalucia (IAA), CSIC, PO Box 3004, 18080 Granada (Spain); Donko, Z [Research Institute for Solid State Physics and Optics, H-1525 Budapest, PO Box, 49 (Hungary)

2009-08-15

A Boltzmann and Monte Carlo analysis of the electron energy distribution function (EEDF) and transport coefficients for air plasmas is presented for the conditions of the Earth troposphere where some transient luminous events (TLEs) such as blue jets, blue starters and gigantic jets have been observed. According to recent model results (Minschwaner et al 2004 J. Climate 17 1272) supported by the halogen occultation experiment, the relative humidity of the atmospheric air between 0 and 15 km can change between 15% and 100% depending on the altitude investigated and the ground temperature. The latter results cover a region of latitudes between -25 deg. S and +25 deg. N, that is, the Earth tropical region where lightning and TLE activity is quite high. The calculations shown here suggest that the relative humidity has a clear impact on the behaviour of the EEDF and magnitude of the transport coefficients of air plasmas at ground (0 km) and room temperature conditions (293 K). At higher altitudes (11 and 15 km), the influence of the relative humidity is negligible when the values of the gas temperature are assumed to be the 'natural' ones corresponding to those altitudes, that is, {approx}215 K (at 11 km) and {approx}198 K (at 15 km). However, it is found that a small enhancement (of maximum 100 K) in the background gas temperature (that could be reasonably associated with the TLE activity) would lead to a remarkable impact of the relative humidity on the EEDF and transport coefficients of air plasmas under the conditions of blue jets, blue starters and gigantic jets at 11 and 15 km. The latter effects are visible for relatively low reduced electric fields (E/N {<=} 25 Td) that could be controlling the afterglow kinetics of the air plasmas generated by TLEs. However, for much higher fields such as, for instance, 400 Td (representative of the fields in the streamer coronas and lightning leaders), the impact of increasing the relative humidity and gas

Electron energy distribution functions and transport coefficients relevant for air plasmas in the troposphere: impact of humidity and gas temperature

International Nuclear Information System (INIS)

Gordillo-Vazquez, F J; Donko, Z

2009-01-01

A Boltzmann and Monte Carlo analysis of the electron energy distribution function (EEDF) and transport coefficients for air plasmas is presented for the conditions of the Earth troposphere where some transient luminous events (TLEs) such as blue jets, blue starters and gigantic jets have been observed. According to recent model results (Minschwaner et al 2004 J. Climate 17 1272) supported by the halogen occultation experiment, the relative humidity of the atmospheric air between 0 and 15 km can change between 15% and 100% depending on the altitude investigated and the ground temperature. The latter results cover a region of latitudes between -25 deg. S and +25 deg. N, that is, the Earth tropical region where lightning and TLE activity is quite high. The calculations shown here suggest that the relative humidity has a clear impact on the behaviour of the EEDF and magnitude of the transport coefficients of air plasmas at ground (0 km) and room temperature conditions (293 K). At higher altitudes (11 and 15 km), the influence of the relative humidity is negligible when the values of the gas temperature are assumed to be the 'natural' ones corresponding to those altitudes, that is, ∼215 K (at 11 km) and ∼198 K (at 15 km). However, it is found that a small enhancement (of maximum 100 K) in the background gas temperature (that could be reasonably associated with the TLE activity) would lead to a remarkable impact of the relative humidity on the EEDF and transport coefficients of air plasmas under the conditions of blue jets, blue starters and gigantic jets at 11 and 15 km. The latter effects are visible for relatively low reduced electric fields (E/N ≤ 25 Td) that could be controlling the afterglow kinetics of the air plasmas generated by TLEs. However, for much higher fields such as, for instance, 400 Td (representative of the fields in the streamer coronas and lightning leaders), the impact of increasing the relative humidity and gas temperature is only slightly

Shielding calculations with SCALE/MAVRIC and comparison with measurements for the TN85 cask with vitrified high level radioactive waste

Science.gov (United States)

Thiele, Holger; Börst, Frank-Michael

2017-09-01

A series of dose rate/spectra measurements in the German interim storage facility Gorleben was carried out at a TN85 cask in April 2009. This type of cask is used for the transport and interim storage of vitrified high level radioactive waste (HAW) from reprocessing. The aim of this work is to assess the shielding component MAVRIC of the SCALE code system with these measurements for the use in the German Bundesamt für Kerntechnische Entsorgungssicherheit (BfE).

The PRISM concept

International Nuclear Information System (INIS)

Circeo, L.J. Jr.; Camacho, S.L.; Tixier, J.S.

1994-01-01

Contaminated soils and buried wastes represent one of the most widespread and costly remediation problems in the United States and other developed countries around the world. This concept of in situ remediation using a plasma arc torch should be directly applicable to many of the contaminated soil remediation needs described the DOE, EPA, and DoD. Plasma Remediation of In Situ Materials (PRISM) could provide a highly efficient, cost-effective, reliable and controllable technique to selectively melt and vitrify any contaminated/buried volume of soils, materials, or objects at any depth underground. If necessary, it could pinpoint underground objects such as buried drums for selective remediation. Plasma arc technology was developed over 30 years ago by NASA for the US space program to simulate reentry temperatures on heat shields. Only recently has this technology begun to emerge as a commercial tool in several industries such as steelmaking, metallurgy, precious metal recovery, and waste disposal. Conceptually, a plasma torch could be used on the ground surface or lowered to the bottom of a small diameter, cased borehole. By raising and operating the torch at progressively higher levels a column of contaminated material would be vitrified and converted into an environmentally safe, glassy residue, highly resistant to leaching. With proper borehole spacing the vitrified columns could be coalesced together to form a contiguous, homogeneous mass of vitrified material which is environmentally safe and highly resistant to leaching

Method of operating a centrifugal plasma arc furnace

International Nuclear Information System (INIS)

Kujawa, S.T.; Battleson, D.M.; Rademacher, E.L. Jr.; Cashell, P.V.; Filius, K.D.; Flannery, P.A.; Whitworth, C.G.

1998-01-01

A centrifugal plasma arc furnace is used to vitrify contaminated soils and other waste materials. An assessment of the characteristics of the waste is performed prior to introducing the waste into the furnace. Based on the assessment, a predetermined amount of iron is added to each batch of waste. The waste is melted in an oxidizing atmosphere into a slag. The added iron is oxidized into Fe 3 O 4 . Time of exposure to oxygen is controlled so that the iron does not oxidize into Fe 2 O 3 . Slag in the furnace remains relatively non-viscous and consequently it pours out of the furnace readily. Cooled and solidified slag produced by the furnace is very resistant to groundwater leaching. The slag can be safely buried in the earth without fear of contaminating groundwater. 3 figs

Plasma surface treatment of Cu by nanosecond-pulse diffuse discharges in atmospheric air

Science.gov (United States)

Cheng, ZHANG; Jintao, QIU; Fei, KONG; Xingmin, HOU; Zhi, FANG; Yu, YIN; Tao, SHAO

2018-01-01

Nanosecond-pulse diffuse discharges could provide high-density plasma and high-energy electrons at atmospheric pressure. In this paper, the surface treatment of Cu by nanosecond-pulse diffuse discharges is conducted in atmospheric air. Factors influencing the water contact angle (WCA), chemical composition and microhardness, such as the gap spacing and treatment time, are investigated. The results show that after the plasma surface treatment, the WCA considerably decreases from 87° to 42.3°, and the surface energy increases from 20.46 mJ m-2 to 66.28 mJ m-2. Results of energy dispersive x-ray analysis show that the concentration of carbon decreases, but the concentrations of oxygen and nitrogen increase significantly. Moreover, the microhardness increases by approximately 30% after the plasma treatment. The aforementioned changes on the Cu surface indicate the plasma surface treatment enhances the hydrophilicity and microhardness, and it cleans the carbon and achieves oxidization on the Cu surface. Furthermore, by increasing the gap spacing and treatment time, better treatment effects can be obtained. The microhardness in the case of a 2.5 cm gap is higher than that in the case of a 3 cm gap. More oxygen and nitrogen species appear on the Cu surface for the 2.5 cm gap treatment than for the 3 cm gap treatment. The WCA significantly decreases with the treatment time when it is no longer than 90 s, and then it reaches saturation. In addition, more oxygen-containing and nitrogen-containing groups appear after extended plasma treatment time. They contribute to the improvement of the hydrophilicity and oxidation on the Cu surface.

Risk analysis of transporting vitrified high-level radioactive waste by train

International Nuclear Information System (INIS)

Schneider, K.A.; Merz, E.

1983-01-01

Reprocessing plants (RPPs) and final disposal sites for vitrified high level radioactive waste (HLW) will be at distant locations in the Federal Republic of Germany (FRG). HLW will also have to be shipped from RPPs located in foreign countries to a final disposal site in the FRG. Thus transportation of HLW on public routes will become necessary. A model of an HLW shipping system is presented which meets the needs of an established nuclear industry. Reference ages of the HLW were assumed to range between about 5 years and about 50 years. Thus HLW shipping systems covering this period are analyzed. The safety of nuclear installations is ensured by means of a design according to the design based accident. The same applies to shipping casks for radioactive materials (RAM) according to the IAEA Regulations. The aim of this work was to make as complete as reasonably possible an estimate of the risk of shipping HLW. The safety of the system was therefore analyzed by means of probabilistic risk assessment. Release of radioactive material due to transportation accidents is considered. 5 references, 5 figures, 6 tables

Field Performance Test of an Air-Cleaner with Photocatalysis-Plasma Synergistic Reactors for Practical and Long-Term Use

Directory of Open Access Journals (Sweden)

Tsuyoshi Ochiai

2014-10-01

Full Text Available A practical and long-term usable air-cleaner based on the synergy of photocatalysis and plasma treatments has been developed. A field test of the air-cleaner was carried out in an office smoking room. The results were compared to previously reported laboratory test results. Even after a treatment of 12,000 cigarettes-worth of tobacco smoke, the air-cleaner maintained high-level air-purification activity (98.9% ± 0.1% and 88% ± 1% removal of the total suspended particulate (TSP and total volatile organic compound (TVOC concentrations, respectively at single-pass conditions. Although the removal ratio of TSP concentrations was 98.6% ± 0.2%, the ratio of TVOC concentrations was 43.8% after a treatment of 21,900 cigarettes-worth of tobacco smoke in the field test. These results indicate the importance of suitable maintenance of the reactors in the air-cleaner during field use.

The Plasma Hearth Process Technology Development Project

International Nuclear Information System (INIS)

Geimer, R.; Batdorf, J.; Wolfe, P.

1993-01-01

The US DOE Office of Technology Development (OTD) is currently evaluating the Plasma Hearth Process (PHP) for potential treatment of several DOE waste types. The PHP is a high-temperature vitrification process that has potential application for a wide range of mixed waste types in both the low-level and transuranic mixed waste categories. The PHP is being tested under both the OTD Mixed Waste Integrated Program and the Buried Waste Integrated Demonstration. Initial testing has been completed on several different surrogate waste forms that are representative of some of the DOE mixed waste streams. Destruction of organic material exceeds that of conventional incineration technologies. The vitrified residual has leaching characteristics comparable to glass formulations produced in the high-level waste program. The first phase of the PHP demonstration project has been successfully completed, and the project is currently beginning a comprehensive second phase of development and testing

Evaluation of non-destructive methods for quality checking of vitrified high level waste

International Nuclear Information System (INIS)

Huddleston, J.; Hutchinson, I.G.; Metcalfe, B; Mossop, J.R.; Taylor, B.L.; Wilkins, C.G.

1990-03-01

Tomography and X-ray absorptiometry have been performed on a container of vitrified high level waste produced by the FINGAL process in 1966. The glass weighed 40-50 kg and when produced contained 10 14 Bq of β/γ activity. The studies have been carried out without recourse to specialised high activity handling facilities. Measurements were carried out by lowering the glass from a shielded container, through a measurement collar, into one of the original storage holes in the floor of the FINGAL plant. The tomographs showed clearly various artefacts in the glass but no cracks or voids were observed within the resolution of the method (0.5-1 mm). The X-ray absorptiometric measurements were made using a 160 kV tube. They showed the presence of about 7% uranium (determined from the magnitude of its K-absorption edge). The resulting strong absorption of X-rays limited the measurements that could be made. (author)

Design and fabrication of a glovebox for the Plasma Hearth Process radioactive bench-scale system

International Nuclear Information System (INIS)

Wahlquist, D.R.

1996-01-01

This paper presents some of the design considerations and fabrication techniques for building a glovebox for the Plasma Hearth Process (PHP) radioactive bench-scale system. The PHP radioactive bench-scale system uses a plasma torch to process a variety of radioactive materials into a final vitrified waste form. The processed waste will contain plutonium and trace amounts of other radioactive materials. The glovebox used in this system is located directly below the plasma chamber and is called the Hearth Handling Enclosure (HHE). The HHE is designed to maintain a confinement boundary between the processed waste and the operator. Operations that take place inside the HHE include raising and lowering the hearth using a hydraulic lift table, transporting the hearth within the HHE using an overhead monorail and hoist system, sampling and disassembly of the processed waste and hearth, weighing the hearth, rebuilding a hearth, and sampling HEPA filters. The PHP radioactive bench-scale system is located at the TREAT facility at Argonne National Laboratory-West in Idaho Falls, Idaho

Radially and temporally resolved electric field of positive streamers in air and modelling of the induced plasma chemistry

Czech Academy of Sciences Publication Activity Database

Hoder, T.; Šimek, Milan; Bonaventura, Z.; Prukner, Václav; Gordillo-Vázquez, F.J.

2016-01-01

Roč. 25, č. 4 (2016), č. článku 045021. ISSN 0963-0252 R&D Projects: GA ČR(CZ) GA15-04023S Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100431201 Program:M Institutional support: RVO:61389021 Keywords : streamer * electric field * Blue Jet * air plasma chemistry * transient luminous event Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.302, year: 2016 http://iopscience.iop.org/article/10.1088/0963-0252/25/4/045021/meta

A Review of Iron Phosphate Glasses and Recommendations for Vitrifying Hanford Waste

Energy Technology Data Exchange (ETDEWEB)

Delbert E. Ray; Chandra S. Ray

2013-11-01

This report contains a comprehensive review of the research conducted, world-wide, on iron phosphate glass over the past ~30 years. Special attention is devoted to those iron phosphate glass compositions which have been formulated for the purpose of vitrifying numerous types of nuclear waste, with special emphasis on the wastes stored in the underground tanks at Hanford WA. Data for the structural, chemical, and physical properties of iron phosphate waste forms are reviewed for the purpose of understanding their (a) outstanding chemical durability which meets all current DOE requirements, (b) high waste loadings which can exceed 40 wt% (up to 75 wt%) for several Hanford wastes, (c) low melting temperatures, can be as low as 900°C for certain wastes, and (d) high tolerance for “problem” waste components such as sulfates, halides, and heavy metals (chromium, actinides, noble metals, etc.). Several recommendations are given for actions that are necessary to smoothly integrate iron phosphate glass technology into the present waste treatment plans and vitrification facilities at Hanford.

Optical breakdown threshold investigation of 1064 nm laser induced air plasmas

International Nuclear Information System (INIS)

Thiyagarajan, Magesh; Thompson, Shane

2012-01-01

We present the theoretical and experimental measurements and analysis of the optical breakdown threshold for dry air by 1064 nm infrared laser radiation and the significance of the multiphoton and collisional cascade ionization process on the breakdown threshold measurements over pressures range from 10 to 2000 Torr. Theoretical estimates of the breakdown threshold laser intensities and electric fields are obtained using two distinct theories namely multiphoton and collisional cascade ionization theories. The theoretical estimates are validated by experimental measurements and analysis of laser induced breakdown processes in dry air at a wavelength of 1064 nm by focusing 450 mJ max, 6 ns, 75 MW max high-power 1064 nm IR laser radiation onto a 20 μm radius spot size that produces laser intensities up to 3 - 6 TW/cm 2 , sufficient for air ionization over the pressures of interest ranging from 10 to 2000 Torr. Analysis of the measured breakdown threshold laser intensities and electric fields are carried out in relation with classical and quantum theoretical ionization processes, operating pressures. Comparative analysis of the laser air breakdown results at 1064 nm with corresponding results of a shorter laser wavelength (193 nm) [M. Thiyagarajan and J. E. Scharer, IEEE Trans. Plasma Sci. 36, 2512 (2008)] and a longer microwave wavelength (10 8 nm) [A. D. MacDonald, Microwave Breakdown in Gases (Wiley, New York, 1966)]. A universal scaling analysis of the breakdown threshold measurements provided a direct comparison of breakdown threshold values over a wide range of frequencies ranging from microwave to ultraviolet frequencies. Comparison of 1064 nm laser induced effective field intensities for air breakdown measurements with data calculated based on the collisional cascade and multiphoton breakdown theories is used successfully to determine the scaled collisional microwave portion. The measured breakdown threshold of 1064 nm laser intensities are then scaled to

The study of selective emission lines from plasma, obtained by evaporating as sample by laser radiation in air and argon media

International Nuclear Information System (INIS)

Sufian, A.; Dimitrov, G.

1993-01-01

Ultra violet visible emission spectroscopic analysis of a plasma produced through laser interaction with a solid probe in different gaseous atmospheres is conducted. Reported are the effects of air and argon, as enveloping media, on the spectral intensities of some lines. The temperature gradient of the plasma, in different atmosphere, is also plotted. In order to improve the detection limits of individual elements, suggested are the possible areas of illuminating the slit of the spectroscopic from the plasma, in respect of the height, above the sample, when working in different gaseous media. (author)

Heat transfer in vitrified radioactive waste

International Nuclear Information System (INIS)

Palancar, M.C.; Luis, M.A.; Luis, P.; Aragon, J.M.; Montero, M.A.

1987-01-01

An experimental method for measuring the thermal conductivity and convection coefficient of borosilicate glass cylinders, containing a simulated high level radioactive waste, is described. A simulation of the thermal behaviour of matrices of solidified waste during the cooling in air, water and a geological repository has been done. The experimental values of the thermal conductivity are ranging from 0.267 to 0.591 w/m K, for matrices with simulated waste contents of 10 to 40% (the waste is simulated by no radioactive isotopes). The convection coefficient for air/cylinders under the operating conditions used is 116 w/m 2 K. The simulated operation of cooling in air shows that about 1-2 days are enough to cool a solidified waste cylinder 0.6m diameter from 900 to 400 0 C. The cooling under water from 400 to near 80 0 C is faster than in air, but sharp temperature gradients within the matrices could be expected. The simulation of geological repositories lead to some criteria of arranging the matrices for avoiding undesirable high temperature points. (author) 1 fig

Spectroscopic Challenges in the Modelling and Diagnostics of High Temperature Air Plasma Radiation for Aerospace Applications

International Nuclear Information System (INIS)

Laux, Christophe O.

2007-01-01

State-of-the-art spectroscopic models of the radiative transitions of interest for Earth re-entry and ground-based diagnostic facilities for aerospace applications are reviewed. The spectral range considered extends from the vacuum ultraviolet to the mid-infrared range (80 nm to 5.5 μm). The modeling results are compared with absolute intensity measurements of the ultraviolet-visible-infrared emission of a well-characterized high-temperature air plasma produced with a 50 kW inductively coupled radio-frequency plasma torch, and with high-resolution absorption spectra from the Center for Astrophysics in the vacuum ultraviolet. The Spectroscopic data required to better model the spectral features of interest for aerospace applications are discussed

Multi-Group Reductions of LTE Air Plasma Radiative Transfer in Cylindrical Geometries

Science.gov (United States)

Scoggins, James; Magin, Thierry Edouard Bertran; Wray, Alan; Mansour, Nagi N.

2013-01-01

Air plasma radiation in Local Thermodynamic Equilibrium (LTE) within cylindrical geometries is studied with an application towards modeling the radiative transfer inside arc-constrictors, a central component of constricted-arc arc jets. A detailed database of spectral absorption coefficients for LTE air is formulated using the NEQAIR code developed at NASA Ames Research Center. The database stores calculated absorption coefficients for 1,051,755 wavelengths between 0.04 µm and 200 µm over a wide temperature (500K to 15 000K) and pressure (0.1 atm to 10.0 atm) range. The multi-group method for spectral reduction is studied by generating a range of reductions including pure binning and banding reductions from the detailed absorption coefficient database. The accuracy of each reduction is compared to line-by-line calculations for cylindrical temperature profiles resembling typical profiles found in arc-constrictors. It is found that a reduction of only 1000 groups is sufficient to accurately model the LTE air radiation over a large temperature and pressure range. In addition to the reduction comparison, the cylindrical-slab formulation is compared with the finite-volume method for the numerical integration of the radiative flux inside cylinders with varying length. It is determined that cylindrical-slabs can be used to accurately model most arc-constrictors due to their high length to radius ratios.

Etching of polymers, proteins and bacterial spores by atmospheric pressure DBD plasma in air

Science.gov (United States)

Kuzminova, A.; Kretková, T.; Kylián, O.; Hanuš, J.; Khalakhan, I.; Prukner, V.; Doležalová, E.; Šimek, M.; Biederman, H.

2017-04-01

Many studies proved that non-equilibrium discharges generated at atmospheric pressure are highly effective for the bio-decontamination of surfaces of various materials. One of the key processes that leads to a desired result is plasma etching and thus the evaluation of etching rates of organic materials is of high importance. However, the comparison of reported results is rather difficult if impossible as different authors use diverse sources of atmospheric plasma that are operated at significantly different operational parameters. Therefore, we report here on the systematic study of the etching of nine different common polymers that mimic the different structures of more complicated biological systems, bovine serum albumin (BSA) selected as the model protein and spores of Bacillus subtilis taken as a representative of highly resistant micro-organisms. The treatment of these materials was performed by means of atmospheric pressure dielectric barrier discharge (DBD) sustained in open air at constant conditions. All tested polymers, BSA and spores, were readily etched by DBD plasma. However, the measured etching rates were found to be dependent on the chemical structure of treated materials, namely on the presence of oxygen in the structure of polymers.

Performance assessment of the disposal of vitrified high-level waste in a clay layer

International Nuclear Information System (INIS)

Mallants, Dirk; Marivoet, Jan; Sillen, Xavier

2001-01-01

Deep disposal is considered a safe solution to the management of high-level radioactive waste. The safety is usually demonstrated by means of a performance assessment. This paper discusses the methodological aspects and some of the results obtained for the performance assessment of the disposal of vitrified high-level waste in a clay layer in Belgium. The calculations consider radionuclide migration through the following multi-barrier components, all of which contribute to the overall safety: (1) engineered barriers and the host clay layer, (2) overlying aquifer, and (3) biosphere. The interfaces between aquifers and biosphere are limited to the well and river pathway. Results of the performance assessment calculations are given in terms of the time evolution of the dose rates of the most important fission and activation products and actinides. The role of the glass matrix in the overall performance of the repository is also discussed

Numerical simulation for the influence of laser-induced plasmas addition on air mass capture of hypersonic inlet

Science.gov (United States)

Zhao, Wei; Dou, Zhiguo; Li, Qian

2012-03-01

The theory of laser-induced plasmas addition to hypersonic airflow off a vehicle to increase air mass capture and improve the performance of hypersonic inlets at Mach numbers below the design value is explored. For hypersonic vehicles, when flying at mach numbers lower than the design one, we can increase the mass capture ratio of inlet through laser-induced plasmas injection to the hypersonic flow upstream of cowl lip to form a virtual cowl. Based on the theory, the model of interaction between laser-induced plasmas and hypersonic flow was established. The influence on the effect of increasing mass capture ratio was studied at different positions of laser-induced plasmas region for the external compression hypersonic inlet at Mach 5 while the design value is 6, the power of plasmas was in the range of 1-8mJ. The main results are as follows: 1. the best location of the plasma addition region is near the intersection of the nose shock of the vehicle with the continuation of the cowl line, and slightly below that line. In that case, the shock generated by the heating is close to the shock that is a reflection of the vehicle nose shock off the imaginary solid surface-extension of the cowl. 2. Plasma addition does increase mass capture, and the effect becomes stronger as more energy is added, the peak value appeared when the power of plasma was about 4mJ, when the plasma energy continues to get stronger, the mass capture will decline slowly.

Air plasma spray processing and electrochemical characterization of SOFC composite cathodes

Science.gov (United States)

White, B. D.; Kesler, O.; Rose, Lars

Air plasma spraying has been used to produce porous composite cathodes containing (La 0.8Sr 0.2) 0.98MnO 3- y (LSM) and yttria-stabilized zirconia (YSZ) for use in solid oxide fuel cells (SOFCs). Preliminary investigations focused on determining the range of plasma conditions under which each of the individual materials could be successfully deposited. A range of conditions was thereby determined that was suitable for the deposition of a composite cathode from pre-mixed LSM and YSZ powders. A number of composite cathodes were produced using different combinations of parameter values within the identified range according to a Uniform Design experimental grid. Coatings were then characterized for composition and microstructure using EDX and SEM. As a result of these tests, combinations of input parameter values were identified that are best suited to the production of coatings with microstructures appropriate for use in SOFC composite cathodes. A selection of coatings representative of the types of observed microstructures were then subjected to electrochemical testing to evaluate the performance of these cathodes. From these tests, it was found that, in general, the coatings that appeared to have the most suitable microstructures also had the highest electrochemical performances, provided that the deposition efficiency of both phases was sufficiently high.

Air plasma spray processing and electrochemical characterization of SOFC composite cathodes

Energy Technology Data Exchange (ETDEWEB)

White, B.D. [Department of Mechanical Engineering, The University of British Columbia, 2054-6250 Applied Sciences Lane, Vancouver, British Columbia (Canada); Kesler, O. [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario (Canada); Rose, Lars [Department of Materials Engineering, The University of British Columbia, 309-6350 Stores Road, Vancouver, British Columbia (Canada); National Research Council (Canada)

2008-03-15

Air plasma spraying has been used to produce porous composite cathodes containing (La{sub 0.8}Sr{sub 0.2}){sub 0.98}MnO{sub 3-y} (LSM) and yttria-stabilized zirconia (YSZ) for use in solid oxide fuel cells (SOFCs). Preliminary investigations focused on determining the range of plasma conditions under which each of the individual materials could be successfully deposited. A range of conditions was thereby determined that was suitable for the deposition of a composite cathode from pre-mixed LSM and YSZ powders. A number of composite cathodes were produced using different combinations of parameter values within the identified range according to a Uniform Design experimental grid. Coatings were then characterized for composition and microstructure using EDX and SEM. As a result of these tests, combinations of input parameter values were identified that are best suited to the production of coatings with microstructures appropriate for use in SOFC composite cathodes. A selection of coatings representative of the types of observed microstructures were then subjected to electrochemical testing to evaluate the performance of these cathodes. From these tests, it was found that, in general, the coatings that appeared to have the most suitable microstructures also had the highest electrochemical performances, provided that the deposition efficiency of both phases was sufficiently high. (author)

Direct measurements of sample heating by a laser-induced air plasma in pre-ablation spark dual-pulse laser-induced breakdown spectroscopy (LIBS).

Science.gov (United States)

Register, Janna; Scaffidi, Jonathan; Angel, S Michael

2012-08-01

Direct measurements of temperature changes were made using small thermocouples (TC), placed near a laser-induced air plasma. Temperature changes up to ~500 °C were observed. From the measured temperature changes, estimates were made of the amount of heat absorbed per unit area. This allowed calculations to be made of the surface temperature, as a function of time, of a sample heated by the air plasma that is generated during orthogonal pre-ablation spark dual-pulse (DP) LIBS measurements. In separate experiments, single-pulse (SP) LIBS emission and sample ablation rate measurements were performed on nickel at sample temperatures ranging from room temperature to the maximum surface temperature that was calculated using the TC measurement results (500 °C). A small, but real sample temperature-dependent increase in both SP LIBS emission and the rate of sample ablation was found for nickel samples heated up to 500 °C. Comparison of DP LIBS emission enhancement values for bulk nickel samples at room temperature versus the enhanced SP LIBS emission and sample ablation rates observed as a function of increasing sample temperature suggests that sample heating by the laser-induced air plasma plays only a minor role in DP LIBS emission enhancement.

Fragmentation process of vitrified ceramic waste (VCW) aiming its incorporation in silico-aluminous refractory concrete for production of refractory bricks

International Nuclear Information System (INIS)

Gomes, L.B.; Brandalise, R.N.; Santos, V. dos; Bergmann, C.P.

2012-01-01

Ceramic industry generates large amounts of waste, usually disposed in landfills. Reuse could minimize their generation and provides sustainable solutions. However, the energy cost of grinding these waste becomes a hindrance to their reuse. This work aims to obtain particle sizes of vitrified ceramic waste (VCW) using a fast, efficient and low cost fragmentation process as well as its use in refractory concrete. The results shows a wide range of particle size of VCW, which can be used as a promising source of raw material for production of refractory concrete. (author)

Transient reflection and transmission of E polarized electromagnetic waves at boundary surface between air and moving isotropic plasma

International Nuclear Information System (INIS)

Saito, Yukimasa

1977-01-01

The transient reflection and transmission waves of E polarized electromagnetic waves coming into the boundary surface between air and moving isotropic plasma were theoretically investigated. By using the Laplace transformation in the moving system, the formulae of Lorentz and inverse Lorentz transformations concerning electromagnetic field were transformed, thus the transient reflection and transmission waves were obtained. These waves were normalized with the angular frequency of the incident waves, and the variation of the wave form was obtained. Examples of the numerical calculation of reflected waves are shown for the plasma moving in parallel to the boundary surface. (Kato, T.)

Study of Air Pollution Due to Plasma Cutting Process and Designing Local Ventilation System with Collector in Central Workshop of Mobarakeh Steel Company

Directory of Open Access Journals (Sweden)

Farideh Atabi

2014-06-01

Full Text Available Background & Objectives : Cutting leads to production of different hazardous agents such as fumes, particles, gases and vapors. In various studies, the effects of fumes, gases, and vapors on workers and environment have been proved. Meanwhile, cutting alloying plates with plasma cutting machine due to containing various alloy materials produces a lot of air pollution. Therefore, using the ventilation system to remove the mentioned pollution has always been noteworthy. Method: This study was performed on plasma cutting machine at Mobarakeh Steel Company. At first, according to ASTM the elements from alloy plates with optical emission spectrometry crm-35000-quantometery were detected, the air pollution from cutting the mentioned plates was sampled and measured using NIOSH 7300 method and according to the ACGIH:VS-72-20, VS-70-12, VS-70-11 VS-916 push-pull ventilation with bag filter collector was designed. Results: Results of sampling from pollution of cutting the alloy material, concentration of iron, lead and cadmium fumes were more than the standard limits. After calculation for push system, air flow volume of 195.163 cfm, outgoing air velocity of 5937.4 fpm and for pull system air flow volume of 12498 cfm, minimum duct velocity of 3000 fpm and velocity pressure of duct of 0.717 inwg, for fan, total pressure of 6.301 inwg, static pressure of 0.587 inwg and power of 20.65 Bhp and for collector with pulse jet cleaning system air to cloth ratio of 7 and dimensions of 6.88ft × 6.56ft × 9.84ft were obtained. Conclusion: The result of study indicated that push pull ventilation compared to other ventilation system s for plasma cutting has more efficiency and makes suitable control for pollution.

Experimental determination of the temperature range of AlO molecular emission in laser-induced aluminum plasma in air

Energy Technology Data Exchange (ETDEWEB)

Bai, Xueshi; Motto-Ros, Vincent [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon Villeurbanne (France); Lei, Wenqi [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon Villeurbanne (France); State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China); Zheng, Lijuan [State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China); Yu, Jin, E-mail: jin.yu@univ-lyon1.fr [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon Villeurbanne (France); Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astrophysics, Shanghai Jiao Tong University, Shanghai 200240 (China)

2014-09-01

Measurements with laser-induced breakdown spectroscopy (LIBS) usually take place in the atmospheric air. For quantitative analysis of metallic elements, oxidation may represent an important issue which can significantly modify the stoichiometry of the plasma. Molecule formation in plasma should be therefore studied and taken into account in the LIBS practice. In this work, we experimentally investigated the temporal evolution and transformation of the plasma induced on an aluminum target by a nanosecond infrared (1064 nm) laser in the atmospheric air, in terms of its temperatures over a large interval of time from hundreds of nanoseconds to tens of microseconds. Such evolution was then correlated to the temporal evolution of the emission intensity from AlO molecules in the ablation plume. In particular, for a given ablation laser pulse energy, the appearance of the molecular emission while the plume cools down allows determining a minimal delay, τ{sub min}, which corresponds to a maximal value of the temperature, T{sub max}, below which the molecular emission begins to be clearly observed and to grow as a function of the delay. Such delay or such temperature indicates the longest delay or the lowest temperature for laser-induced plasma to be suitable for a correct analysis of metallic elements without significant influence of the alternation of the stoichiometry by oxidation. In our experiment, the values of τ{sub min} and T{sub max} have been determined for a range of ablation laser pulse energies from 5 mJ to 50 mJ. These values lie respectively in the range of 3 to 15 μs for τ{sub min}, and 4500 K to 6600 K in terms of the molecule temperature for T{sub max}. Beyond the practical interest for LIBS, our results provide also insights to the kinetics of the AlO molecule formation in laser-induced plasma. - Highlights: • Determination of the temperatures in laser-induced plasma up to tens of microseconds • Determination of the molecule temperature by fitting

Iron Phosphate Glass for Vitrifying Hanford AZ102 LAW in Joule Heated and Cold Crucible Induction Melters - 12240

Energy Technology Data Exchange (ETDEWEB)

Day, Delbert E.; Brow, Richard K.; Ray, Chandra S.; Reis, Signo T. [Missouri University of Science and Technology, 1870 Miner Circle, Rolla, MO 65409 (United States); Kim, Cheol-Woon [MO-SCI Corporation, 4040 HyPoint North, Rolla, MO 65401 (United States); Vienna, John D.; Sevigny, Gary [Pacific North West National Laboratory, Battelle Blvd., Richland, WA 99352 (United States); Peeler, David; Johnson, Fabienne C.; Hansen, Eric K. [Savannah River National Laboratory, Savannah River Site, 999-W, Aiken, SC 29803 (United States); Soelberg, Nick [Idaho National Laboratory, 2525 Fremont Avenue, Idaho Falls, ID 83415 (United States); Pegg, Ian L.; Gan, Hao [Catholic University of America, 620 Michigan Avenue, N.E., Washington, DC 20064 (United States)

2012-07-01

An iron phosphate composition for vitrifying a high sulfate (∼17 wt%) and high alkali (∼80 wt%) Hanford low activity waste (LAW), known as AZ-102 LAW, has been developed for processing in a Joule Heated Melter (JHM) or a Cold Crucible Induction Melter (CCIM). This composition produced a glass waste form, designated as MS26AZ102F-2, with a waste loading of 26 wt% of the AZ-102 which corresponded to a total alkali and sulfate (represented as SO{sub 3}) content of 21 and 4.4 wt%, respectively. A slurry (7 M Na{sup +}) of MS26AZ102F-2 simulant was melted continuously at temperatures between 1030 and 1090 deg. C for 10 days in a small JHM at PNNL and for 70 hours in a CCIM at INL. The as-cast glasses produced in both melters and in trial laboratory experiments along with their canister centerline cooled (CCC) counterparts met the requirements for the Product Consistency Test (PCT) and the Vapor Hydration Test (VHT) responses in the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Contract. These glass waste forms retained up to 77 % of the SO{sub 3} (3.3 wt%), 100% of the Cesium, and 33 to 44% of the rhenium (used as a surrogate for Tc) all of which either exceeded or were comparable to the retention limit for these species in borosilicate glass nuclear waste form. Analyses of commercial K-3 refractory lining and the Inconel 693 metal electrodes used in JHM indicated only minimum corrosion of these components by the iron phosphate glass. This is the first time that an iron phosphate composition was melted continuously in a slurry fed JHM and in the US, thereby, demonstrating that iron phosphate glasses can be used as alternative hosts for vitrifying nuclear waste. The following conclusions are drawn from the results of the present work. (1) An iron phosphate composition, designated as MS26AZ102F-2, containing 26 wt% of the simulated high sulfate (17 wt%), high alkali (80 wt%) Hanford AZ-102 LAW meets all the criteria for processing in a JHM and CCIM. This

Constrained sintering of an air-plasma-sprayed thermal barrier coating

International Nuclear Information System (INIS)

Cocks, A.C.F.; Fleck, N.A.

2010-01-01

A micromechanical model is presented for the constrained sintering of an air-plasma-sprayed, thermal barrier coating upon a thick superalloy substrate. The coating comprises random splats with intervening penny-shaped cracks. The crack faces make contact at asperities, which progressively sinter in-service by interfacial diffusion, accommodated by bulk creep. Diffusion is driven by the reduction in interfacial energy at the developing contacts and by the local asperity contact stress. At elevated operating temperature, both sintering and creep strains accumulate within the plane of the coating. The sensitivities of sintering rate and microstructure evolution rate to the kinetic parameters and thermodynamic driving forces are explored. It is demonstrated that the sintering response is governed by three independent timescales, as dictated by the material and geometric properties of the coating. Finally, the role of substrate constraint is assessed by comparing the rate of constrained sintering with that for free sintering.

Lightweight Portable Plasma Medical Device - Plasma Engineering Research Laboratory

Science.gov (United States)

2015-12-01

monocytic leukemia cancer cells ( THP -1) were also tested and the results 19 demonstrate that a preference for apoptosis in plasma treated THP -1...unanswered questions. We have tested the effects of indirect exposure of non-thermal air plasma on monocytic leukemia cancer cells ( THP -1) and deciphering... tested and the results are shown in Fig. above. The results demonstrate that a preference for apoptosis in plasma treated THP -1 cells under

Modeling of Plasma-Induced Ignition and Combustion

National Research Council Canada - National Science Library

Boyd, Iain D; Keidar, Michael

2008-01-01

.... Phenomena that must be considered in an electrothermal chemical gun model include the initial capillary plasma properties, the plasma-air interaction, plasma sheath effects, and the plasma-propellant interaction itself...

Cryo-electron microscopy of vitrified SV40 minichromosomes: the liquid drop model.

Science.gov (United States)

Dubochet, J; Adrian, M; Schultz, P; Oudet, P

1986-03-01

The structure of SV40 minichromosomes has been studied by cryo-electron microscopy of vitrified thin layers of solution. In high-salt buffer (130 mM NaCl), freshly prepared minichromosomes are condensed into globules 30 nm or more in diameter. On the micrograph, they appear to be formed by the close packing of 10 nm granules which give rise to a 10 nm reflection in the optical diffractogram. The globules can adopt many different conformations. At high concentration, they fuse into a homogeneous 'sea' of closely packed 10 nm granules. In low-salt buffer (less than 10 mM NaCl), the globules open, first into 10 nm filaments, and then into nucleosome-strings. The 'liquid drop' model is proposed to explain the condensed structure of the minichromosome in high-salt buffer: nucleosomes stack specifically on top of one another, thus forming the 10 nm filaments. 10 nm filaments in turn, tend to aggregate laterally. Optimizing both these interactions results in the condensation of 10 nm filaments or portions thereof into a structure similar to that of a liquid. Some implications of this model for the structure of cellular chromatin are discussed.

The design and construction of the windscale vitrification plant and vitrified product store

International Nuclear Information System (INIS)

Heafield, W.; Woodall, A.; Elsden, A.D.

1987-01-01

The paper describes the background of High Level Waste storage and vitrification development in the UK and its application to Reprocessing Operations at Sellafield. The main stages in the vitrification process and associated maintenance facilities are described together with the layout of the Windscale Vitrification Plant (WVP) and associated Vitrified Product Store (VPS). The design and construction techniques employed for example, the use of Computer Aided Design and the effect of automatic pipe bending/orbital welding and the use of precast units for cell construction, are discussed and current construction progress is highlighted. The vitrification process uses complex mechanical plant operating in high temperature and radiation fields. An extensive engineering and process development programme has been carried out. A full scale inactive facility (FSIF) has been constructed and the objectives and results from the operation of FSIF are presented. In addition to engineering and process development, a comprehensive programme of glass technology development has been carried out to establish maximum waste incorporation levels, reaction kinetic and product properties of the candidate glass formulations

Treatment of mixed wastes by thermal plasma discharges; Tratamiento de desechos mixtos por descargas de plasma termico

Energy Technology Data Exchange (ETDEWEB)

Diaz A, L.V.; Pacheco S, J.O.; Pacheco P, M.; Monroy G, F.; Emeterio H, M. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: lauradiazarch@yahoo.com.mx

2007-07-01

The National Institute of Nuclear Research (ININ) uses an ion exchange resin: IRN 150 (copolymer styrene Divynilbencene) in the TRIGA Mark III reactor to absorb polluted particles with heavy metals and radioactive particles of low level. Once the capacity of filtrate of the resin is exceeded, it is replaced and considered with a mixed waste. This work is based on taking advantage of the advantages of the technique of the thermal plasma in a unique process: (high energy density 105W/cm{sup 3} high enthalpy, high reactivity chemical, high operation temperatures 6000-11500K and quick quenching 106K/s) for the degradation and vitrification of the resin IRN 150. The reactor of plasma is compact and it works to atmospheric pressure and reduced thermal inertia. Therefore, the main parameters involved during the degradation tests and vitrification are: plasma current, voltage, gas flow and distance among the electrodes. The used vitreous matrix, is obtained from a ceramic clay composed by an oxides mixture which are characterized by their good resistance to mechanical impacts and erosion caused by the water. The ceramic clay and the resin IRN 150 were analyzed before the treatment by Scanning Electron Microscopy (MEB), X-ray Diffraction (DRX), Thermal gravimetry (TGA) once vitrified the materials were also analyzed by MEB and DRX. It is obtained as a result that the material more appropriate to be used as vitreous matrix it is a ceramic clay formed by several oxides, being operated the plasma system with a current of 115A, voltage of 25V, flow of the argon gas of 5 l/m and a distance among electrodes of 10mm. With the development of the proposed technology and the material for the vitreous matrix, be rotted to try in a future a great variety of mixed waste. (Author)

A review and analysis of European industrial experience in handling LWR [light water reactor] spent fuel and vitrified high-level waste

International Nuclear Information System (INIS)

Blomeke, J.O.

1988-06-01

The industrial facilities that have been built or are under construction in France, the United Kingdom, Sweden, and West Germany to handle light-water reactor (LWR) spent fuel and canisters of vitrified high-level waste before ultimate disposal are described and illustrated with drawings and photographs. Published information on the operating performances of these facilities is also given. This information was assembled for consideration in planning and design of similar equipment and facilities needed for the Federal Waste Management System in the United States. 79 refs., 71 figs., 10 tabs

Plasma Hearth Process vitrification of DOE low-level mixed waste

International Nuclear Information System (INIS)

Gillins, R.L.; Geimer, R.M.

1995-01-01

The Plasma Hearth Process (PHP) demonstration project is one of the key technology projects in the Department of Energy (DOE) Office of Technology Development Mixed Waste Focus Area. The PHP is recognized as one of the more promising solutions to DOE's mixed waste treatment needs, with potential application in the treatment of a wide variety of DOE mixed wastes. The PHP is a high temperature vitrification process using a plasma arc torch in a stationary, refractory lined chamber that destroys organics and stabilizes the residuals in a nonleaching, vitrified waste form. This technology will be equally applicable to low-level mixed wastes generated by nuclear utilities. The final waste form will be volume reduced to the maximum extent practical, because all organics will have been destroyed and the inorganics will be in a high-density, low void-space form and little or no volume-increasing glass makers will have been added. Low volume and high integrity waste forms result in low disposal costs. This project is structured to ensure that the plasma technology can be successfully employed in radioactive service. The PHP technology will be developed into a production system through a sequence of tests on several test units, both non-radioactive and radioactive. As the final step, a prototype PHP system will be constructed for full-scale radioactive waste treatment demonstration

Development of improved leaching techniques for vitrified radioactive waste products

International Nuclear Information System (INIS)

Vaswani, G.A.; Yeotikar, R.G.; Rastogi, R.C.; Sunder Rajan, N.S.

1979-01-01

A critical review of the current techniques for evaluating the leach resistance of vitrified radioactive wastes has been made. Inadequacy of the available leaching techniques, with respect to their adoption as standard technique on an international scale, has been brought out for the three broad catagories of aqueous attack viz., (i) simple contact with leachant at a particular temperature, (ii) once-through or recirculatory flow of leachant at variable temperatures and flow rates, and (iii) contact with freshly distilled hot water in soxhelet type of extractor. In an effort to evolve a standard leaching technique in the latter two categories of aqueous attack, development of two leaching units viz., 'Dynamic Leaching Unit' and 'Modified Soxhlet Unit' is described. Both these units offer good control and wide flexibility on the important parameters affecting leaching such as leachant temperature, flow rate of residence time of leachant and ratio of leachant volume to sample surface area. The dynamic leaching units also offers a good control and flexibility on the two additional parameters viz., the composition and pH of the leachant. In the modified soxhlet unit the composition and pH of the leachant remains near to that of distilled water. The leach rate results have been found to be reproducible. A need for framing the set of standard conditions for adoption of these units in evolution of standard leaching techniques has been indicated. (auth.)

Statistical process control: An approach to quality assurance in the production of vitrified nuclear waste

International Nuclear Information System (INIS)

Pulsipher, B.A.; Kuhn, W.L.

1987-01-01

Current planning for liquid high-level nuclear wastes existing in the United States includes processing in a liquid-fed ceramic melter to incorporate it into a high-quality glass, and placement in a deep geologic repository. The nuclear waste vitrification process requires assurance of a quality product with little or no final inspection. Statistical process control (SPC) is a quantitative approach to one quality assurance aspect of vitrified nuclear waste. This method for monitoring and controlling a process in the presence of uncertainties provides a statistical basis for decisions concerning product quality improvement. Statistical process control is shown to be a feasible and beneficial tool to help the waste glass producers demonstrate that the vitrification process can be controlled sufficiently to produce an acceptable product. This quantitative aspect of quality assurance could be an effective means of establishing confidence in the claims to a quality product

Statistical process control: An approach to quality assurance in the production of vitrified nuclear waste

International Nuclear Information System (INIS)

Pulsipher, B.A.; Kuhn, W.L.

1987-02-01

Current planning for liquid high-level nuclear wastes existing in the US includes processing in a liquid-fed ceramic melter to incorporate it into a high-quality glass, and placement in a deep geologic repository. The nuclear waste vitrification process requires assurance of a quality product with little or no final inspection. Statistical process control (SPC) is a quantitative approach to one quality assurance aspect of vitrified nuclear waste. This method for monitoring and controlling a process in the presence of uncertainties provides a statistical basis for decisions concerning product quality improvement. Statistical process control is shown to be a feasible and beneficial tool to help the waste glass producers demonstrate that the vitrification process can be controlled sufficiently to produce an acceptable product. This quantitative aspect of quality assurance could be an effective means of establishing confidence in the claims to a quality product. 2 refs., 4 figs

Analysis of surface leaching processes in vitrified high-level nuclear wastes using in-situ raman imaging and atomistic modeling. 1998 annual progress report

International Nuclear Information System (INIS)

Clark, D.E.; Simmons, J.H.

1998-01-01

'The research objective was to test and develop optical methods for real-time, remote and in-situ testing of corrosion processes on the surface of vitrified nuclear wastes. This report summarizes the research conducted in the first 1.5 years of a 3 year grant. At this point, the authors have identified the conditions for optimal tests and demonstrated that both IR reflection and Raman spectroscopies can be used to determine the dealkalization process in the surface of simple glasses in real time.'

Methods of vitrifying waste with low melting high lithia glass compositions

Science.gov (United States)

Jantzen, Carol M.; Pickett, John B.; Cicero-Herman, Connie A.; Marra, James C.

2001-01-01

The invention relates to methods of vitrifying waste and for lowering the melting point of glass forming systems by including lithia formers in the glass forming composition in significant amounts, typically from about 0.16 wt % to about 11 wt %, based on the total glass forming oxides. The lithia is typically included as a replacement for alkali oxide glass formers that would normally be present in a particular glass forming system. Replacement can occur on a mole percent or weight percent basis, and typically results in a composition wherein lithia forms about 10 wt % to about 100 wt % of the alkali oxide glass formers present in the composition. The present invention also relates to the high lithia glass compositions formed by these methods. The invention is useful for stabilization of numerous types of waste materials, including aqueous waste streams, sludge solids, mixtures of aqueous supernate and sludge solids, combinations of spent filter aids from waste water treatment and waste sludges, supernate alone, incinerator ash, incinerator offgas blowdown, or combinations thereof, geological mine tailings and sludges, asbestos, inorganic filter media, cement waste forms in need of remediation, spent or partially spent ion exchange resins or zeolites, contaminated soils, lead paint, etc. The decrease in melting point achieved by the present invention desirably prevents volatilization of hazardous or radioactive species during vitrification.

LASER PLASMA AND LASER APPLICATIONS: Plasma transparency in laser absorption waves in metal capillaries

Science.gov (United States)

Anisimov, V. N.; Kozolupenko, A. P.; Sebrant, A. Yu

1988-12-01

An experimental investigation was made of the plasma transparency to heating radiation in capillaries when absorption waves propagated in these capillaries as a result of interaction with a CO2 laser pulse of 5-μs duration. When the length of the capillary was in excess of 20 mm, total absorption of the radiation by the plasma was observed at air pressures of 1-100 kPa. When the capillary length was 12 mm, a partial recovery of the transparency took place. A comparison was made with the dynamics and recovery of the plasma transparency when breakdown of air took place near the free surface.

Infrared Absorption Spectroscopic Study on Reaction between Self-Assembled Monolayers and Atmospheric-Pressure Plasma

Directory of Open Access Journals (Sweden)

Masanori Shinohara

2015-01-01

Full Text Available Plasma is becoming increasingly adopted in bioapplications such as plasma medicine and agriculture. This study investigates the interaction between plasma and molecules in living tissues, focusing on plasma-protein interactions. To this end, the reaction of air-pressure air plasma with NH2-terminated self-assembled monolayer is investigated by infrared spectroscopy in multiple internal reflection geometry. The atmospheric-pressure plasma decomposed the NH2 components, the characteristic units of proteins. The decomposition is attributed to water clusters generated in the plasma, indicating that protein decomposition by plasma requires humid air.

Nonthermal plasma technology for organic destruction

International Nuclear Information System (INIS)

Heath, W.O.; Birmingham, J.G.

1995-01-01

Pacific Northwest Laboratory (PNL) is investigating the use of nonthermal, electrically driven plasmas for destroying organic contaminants near ambient temperatures and pressures. Three different plasma systems have been developed to treat organics in air, water, and soil. These systems are the gas-phase corona reactor (GPCR) for treating air, the liquid phase corona reactor for treating water, and the in-situ corona for treating soils. This paper focuses on the GPCR as an alternative to other air purification technologies for treating off-gasses from remedial action efforts and industrial emissions

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.

Beta-adrenergic control of plasma glucose and free fatty acid levels in the air-breathing African catfish Clarias gariepinus Burchell 1822

NARCIS (Netherlands)

van Heeswijk, JCF; Vianen, GJ; van den Thillart, GEEJM; Zaagsma, J

In several water-breathing fish species, P-adrenergic receptor stimulation by noradrenaline leads to a decrease in plasma free fatty acid (FFA) levels, as opposed to an increase in air-breathing mammals. We hypothesised that this change in adrenergic control is related to the mode of breathing.

Effect of composition variations on the long-term wasteform behavior of vitrified domestic waste incineration fly-ash purification residues; Influence des variations de composition des vitrifiats de refiom - residus d'epuration des fumees d'incineration d'ordures menageres - sur leur comportement a long terme

Energy Technology Data Exchange (ETDEWEB)

Frugier, P.

2000-07-01

The effect of variations in the composition of fly-ash purification residue from incinerated domestic waste on the quality of the containment achieved by vitrification was investigated. Three main factors determine the long-term containment quality: the production of a vitrified wasteform, the occurrence of possible crystallization, and the key parameters of long-term alteration in aqueous media. Each of these aspects is described within a composition range defined by variations in the three major elements. (silicon, calcium and aluminum) and two groups of constituents (alkali metals and toxic elements). The silicon fraction in the fly-ash residue was found to be decisive: it is impossible to obtain a satisfactory vitrified wasteform below a given silicon concentration. Compounds with the lowest silica content also exhibited the greatest tendency to crystallize under the cooling conditions prevailing in industrial processes (the dominant crystallized phase is a melilite that occupies a significant fraction of the material and considerably modifies the alteration mechanisms). The initial alteration rate in pure water and the altered glass thickness measured in a closed system at an advanced stage of the dissolution reaction are both inversely related to the silicon concentration in the glass. Several types of long-term behavior were identified according to the composition range, the process conditions and the vitrified waste disposal scenario. Four distinct 'classes' of vitrified wasteform were defined for direct application in industrial processes. (author)

Air pollution by c-PAHs and plasma levels of p53 and p21WAF1 proteins

Czech Academy of Sciences Publication Activity Database

Rössner ml., Pavel; Binková, Blanka; Milcová, Alena; Solanský, I.; Židzik, J.; Lyubomirova, K.; Farmer, P. B.; Šrám, Radim

2007-01-01

Roč. 620, - (2007), s. 34-40 ISSN 0027-5107 R&D Projects: GA MŽP SI/340/2/00; GA MŽP SL/740/5/03 Grant - others:EU(GB) 2000 -00091 Institutional research plan: CEZ:AV0Z50390512 Source of funding: R - rámcový projekt EK Keywords : air pollution * p53 and p21WAF1 plasma levels Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 4.159, year: 2007

Hydrophobic recovery of repeatedly plasma-treated silicone rubber .2. A comparison of the hydrophobic recovery in air, water, or liquid nitrogen

NARCIS (Netherlands)

Everaert, EP; VanderMei, HC; Busscher, HJ

1996-01-01

Surfaces of medical grade silicone rubber (Q7-4750, Dow Coming) were modified by repeated (six times) RF plasma treatments using various discharge gases: oxygen, argon, carbon dioxide, and ammonia. The treated samples were stored for a period of 3 months in ambient air, water, or liquid nitrogen.

Deep Desulfurization of Diesel Fuels with Plasma/Air as Oxidizing Medium, Diperiodatocuprate (III) as Catalyzer and Ionic Liquid as Extraction Solvent

International Nuclear Information System (INIS)

Ban Lili; Liu Ping; Ma Cunhua; Dai Bin

2013-01-01

In this paper, the oxidative desulfurization (ODS) system is directly applied to deal with the catalytic oxidation of sulfur compounds of sulfur-containing model oil by dielectric barrier discharge (DBD) plasma in the presence of air plus an extraction step with the oxidation-treated fuel put over ionic liquid [BMIM]FeCl 4 (1-butyl-3-methylimidazolium tetrachloroferrate). This new system exhibited an excellent desulfurization effect. The sulfur content of DBT in diesel oil decreased from 200 ppm to 4.92 ppm (S removal rate up to 97.5%) under the following optimal reaction conditions: air flow rate (ν) of 60 mL/min, amplitude of applied voltage (U) on DBD of 16 kV, input frequency (f) of 79 kHz, catalyst amount (ω) of 1.25 wt%, reaction time (t) of 10 min. Moreover, a high desulfurization rate was obtained during oxidation of benzothiophene (BT) or 4,6-DMDBT (4,6-dimethyl-dibenzothiophene) under the aforementioned conditions. The oxidation reactivity of different S compounds was decreased in the order of DBT, 4,6-DMDBT and BT. The remarkable advantage of the novel ODS system is that the desulfurization condition applies in the presence of air at ambient conditions without peroxides, aqueous solvent or biphasic oil-aqueous solution system. (plasma technology)

Development and demonstration of prototype transportation equipment for emplacing HL vitrified waste canisters into small diameter bored horizontal disposal cells

International Nuclear Information System (INIS)

Seidler, Wolf K.; Bosgiraud, Jean-Michel; Londe, Louis

2008-01-01

Over a period of 4 and years the National Radioactive Waste Management Agency (Andra), working with a variety of Contractors mostly specializing in nuclear orientated mechanical applications, successfully designed, fabricated and demonstrated 2 very different prototype high level waste transport systems. The first system, based on air cushion technology, was developed primarily for very heavy loads (17 to 45 tonnes). The results of this work are described in a separate presentation (Paper 21) at this Conference. The second system, developed by Andra within the framework of the ESDRED Project, generally referred to as the 'Pushing Robot System' for vitrified waste canisters, is the subject of this paper. The 'Pushing Robot System' is a part of the French national disposal concept that is described in Andra's 'Dossier 2005'. The latter is a public document that can be viewed on Andra's web site (www.andra.fr). The 'Pushing Robot System' system is designed for the deep geological disposal (in clay formations) of 'C' type vitrified waste canisters. In its entirety the system provides for the transport, emplacement and, if necessary, the retrieval of those canisters. Nothing in the design of the Andra emplacement equipment would preclude its utilization in horizontal openings in other types of geological settings. Over a period of some 8 years Andra has developed the 'Pushing Robot System' in 3 phases. Initially there was only the 'Conceptual Design' (Phase 1) which was incorporated in the Dossier 2005. This was followed by Phase 2 i.e. the design and fabrication of a simplified full scale prototype system henceforth referred to a P1, which includes a Pushing Robot, a Dummy Canister and a Test Bench. P1 details were also incorporated in the Dossier 2005. Finally, during Phase 3, a second more comprehensive full scale prototype system P2 has been designed and is being assembled and tested this month. This system includes a Transport Shuttle, a Transfer Shielding Cask, a

Untitled

Indian Academy of Sciences (India)

et al 1990) to stabilize solid toxic and nuclear waste material. The furnace employs a thermal plasma torch to melt and vitrify the waste components. 6. Conclusion. The use of plasma torches at ... time of the particles in the plasma environment, normally of the order of several milliseconds. This residence time is adequate for ...

Manganese oxide octahedral molecular sieve K-OMS-2 as catalyst in post plasma-catalysis for trichloroethylene degradation in humid air.

Science.gov (United States)

Nguyen Dinh, M T; Giraudon, J-M; Vandenbroucke, A M; Morent, R; De Geyter, N; Lamonier, J-F

2016-08-15

The total oxidation of trichloroethylene (TCE) in air at low relative humidity (RH=10%) in the presence of CO2 (520ppmv) was investigated in function of energy density using an atmospheric pressure negative DC luminescent glow discharge combined with a cryptomelane catalyst positioned downstream of the plasma reactor at a temperature of 150°C. When using Non-Thermal Plasma (NTP) alone, it is found a low COx (x=1-2) yield in agreement with the detection of gaseous polychlorinated by-products in the outlet stream as well as ozone which is an harmful pollutant. Introduction of cryptomelane enhanced trichloroethylene removal, totally inhibited plasma ozone formation and increased significantly the COx yield. The improved performances of the hybrid system were mainly ascribed to the total destruction of plasma generated ozone on cryptomelane surface to produce active oxygen species. Consequently these active oxygen species greatly enhanced the abatement of the plasma non-reacted TCE and completely destroyed the hazardous plasma generated polychlorinated intermediates. The facile redox of Mn species associated with oxygen vacancies and mobility as well as the textural properties of the catalyst might also contribute as a whole to the efficiency of the process. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparisons of Force Measurement Methods for DBD Plasma Actuators in Quiescent Air

Science.gov (United States)

Hoskinson, Alan R.; Hershkowitz, Noah; Ashpis, David E.

2009-01-01

We have performed measurements of the force induced by both single (one electrode insulated) and double (both electrodes insulated) dielectric barrier discharge plasma actuators in quiescent air. We have shown that, for single barrier actuators with cylindrical exposed electrodes, as the electrode diameter decrease the force efficiencies increase much faster than a previously reported linear trend. This behavior has been experimentally verified using two different measurement techniques: stagnation probe measurements of the induced flow velocity and direct measurement of the force using an electronic balance. Actuators with rectangular cross-section exposed electrodes do not show the same rapid increase at small thicknesses. We have also shown that the induced force is independent of the material used for the exposed electrode. The same techniques have shown that the induced force of a double barrier actuator increases with decreasing narrow electrode diameter.

Manganese oxide octahedral molecular sieve K-OMS-2 as catalyst in post plasma-catalysis for trichloroethylene degradation in humid air

International Nuclear Information System (INIS)

Nguyen Dinh, M.T.; Giraudon, J.-M.; Vandenbroucke, A.M.; Morent, R.; De Geyter, N.; Lamonier, J.-F.

2016-01-01

Highlights: • Post plasma catalysis: negative DC glow discharge combined with a cryptomelane. • The α-MnO_2 catalyst totally decomposes the NTP generated ozone. • Active oxygen oxidizes the end-up plasma VOC by-products. - Abstract: The total oxidation of trichloroethylene (TCE) in air at low relative humidity (RH = 10%) in the presence of CO_2 (520 ppmv) was investigated in function of energy density using an atmospheric pressure negative DC luminescent glow discharge combined with a cryptomelane catalyst positioned downstream of the plasma reactor at a temperature of 150 °C. When using Non-Thermal Plasma (NTP) alone, it is found a low COx (x = 1–2) yield in agreement with the detection of gaseous polychlorinated by-products in the outlet stream as well as ozone which is an harmful pollutant. Introduction of cryptomelane enhanced trichloroethylene removal, totally inhibited plasma ozone formation and increased significantly the COx yield. The improved performances of the hybrid system were mainly ascribed to the total destruction of plasma generated ozone on cryptomelane surface to produce active oxygen species. Consequently these active oxygen species greatly enhanced the abatement of the plasma non-reacted TCE and completely destroyed the hazardous plasma generated polychlorinated intermediates. The facile redox of Mn species associated with oxygen vacancies and mobility as well as the textural properties of the catalyst might also contribute as a whole to the efficiency of the process.

Manganese oxide octahedral molecular sieve K-OMS-2 as catalyst in post plasma-catalysis for trichloroethylene degradation in humid air

Energy Technology Data Exchange (ETDEWEB)

Nguyen Dinh, M.T. [Université Lille, Sciences et Technologies, Unité de Catalyse et Chimie du Solide UMR CNRS UCCS 8181, 59655 Villeneuve d’Ascq (France); The University of Da-Nang, University of Science and Technology, 54, Nguyen Luong Bang, Da-Nang (Viet Nam); Giraudon, J.-M., E-mail: jean-marc.giraudon@univ-lille1.fr [Université Lille, Sciences et Technologies, Unité de Catalyse et Chimie du Solide UMR CNRS UCCS 8181, 59655 Villeneuve d’Ascq (France); Vandenbroucke, A.M.; Morent, R.; De Geyter, N. [Ghent University, Faculty of Engineering and Architecture, Department of Applied Physics, Research Unit Plasma Technology, Sint-Pietersnieuwstraat 41, 9000 Ghent (Belgium); Lamonier, J.-F. [Université Lille, Sciences et Technologies, Unité de Catalyse et Chimie du Solide UMR CNRS UCCS 8181, 59655 Villeneuve d’Ascq (France)

2016-08-15

Highlights: • Post plasma catalysis: negative DC glow discharge combined with a cryptomelane. • The α-MnO{sub 2} catalyst totally decomposes the NTP generated ozone. • Active oxygen oxidizes the end-up plasma VOC by-products. - Abstract: The total oxidation of trichloroethylene (TCE) in air at low relative humidity (RH = 10%) in the presence of CO{sub 2} (520 ppmv) was investigated in function of energy density using an atmospheric pressure negative DC luminescent glow discharge combined with a cryptomelane catalyst positioned downstream of the plasma reactor at a temperature of 150 °C. When using Non-Thermal Plasma (NTP) alone, it is found a low COx (x = 1–2) yield in agreement with the detection of gaseous polychlorinated by-products in the outlet stream as well as ozone which is an harmful pollutant. Introduction of cryptomelane enhanced trichloroethylene removal, totally inhibited plasma ozone formation and increased significantly the COx yield. The improved performances of the hybrid system were mainly ascribed to the total destruction of plasma generated ozone on cryptomelane surface to produce active oxygen species. Consequently these active oxygen species greatly enhanced the abatement of the plasma non-reacted TCE and completely destroyed the hazardous plasma generated polychlorinated intermediates. The facile redox of Mn species associated with oxygen vacancies and mobility as well as the textural properties of the catalyst might also contribute as a whole to the efficiency of the process.

Acoustic Measurement of the Length of Air-plasma Filament Induced by an Intense Femtosecond Laser Pulse

Directory of Open Access Journals (Sweden)

Wu Si-Qing

2017-01-01

Full Text Available The paper studies acoustic emission from air-plasma filament induced by a strong femtosecond laser pulse. Acoustic signal is detected with a sensitive directional microphone. Acoustic measurement provides a new method to determine the length of a filament. Compared with other methods, acoustic measurement is simpler, more sensitive, and with higher spatial resolution. Information of filament length is experimentally acquired through measuring acoustic pressure at different position of filament. On the basis of the relationship between acoustic signal and free-electron density in filament, profile of free-electron density is demonstrated

Ultrasound enhanced plasma treatment of glass-fibre-reinforced polyester in atmospheric pressure air for adhesion improvement

DEFF Research Database (Denmark)

Kusano, Yukihiro; Singh, Shailendra Vikram; Norrman, Kion

2011-01-01

A glass-fibre-reinforced polyester (GFRP) plate was treated with dielectric barrier discharge (DBD) at atmospheric pressure in air for adhesion improvement. The effects of ultrasonic irradiation using a high-power gas-jet generator during the treatment were investigated. The optical emission...... damage of the GFRP plates. The polar component of the surface energy of the polyester plate was 21 mJ/m2 before the treatment, increased markedly to 52 mJ/m2 after 2-s plasma treatment without ultrasonic irradiation, and further increased slightly after longer treatments. In addition, the polar component...

Improvement of air permeability of Bubbfil nanofiber membrane

Directory of Open Access Journals (Sweden)

Wang Fei-Yan

2018-01-01

Full Text Available Nanofiber membranes always have extremely high filter efficiency and remarkably low pressure drop. In order to further improve air permeability of bubbfil nanofiber membranes, the plasma technology is used for surface treatment in this paper. The results show that plasma treatment can improve air permeability by 4.45%. Under higher power plasma treatment, earthworm like etchings are produced on the membrane surface with fractal dimensions of about 1.138.

Leaching properties of slag generated by a gasification/vitrification unit: the role of pH, particle size, contact time and cooling method used.

Science.gov (United States)

Moustakas, K; Mavropoulos, A; Katsou, E; Haralambous, K J; Loizidou, M

2012-03-15

The environmental impact from the operation of thermal waste treatment facilities mainly originates from the air emissions, as well as the generated solid residues. The objective of this paper is to examine the slag residue generated by a demonstration plasma gasification/vitrification unit and investigate the composition, the leaching properties of the slag under different conditions, as well as the role of the cooling method used. The influence of pH, particle size and contact time on the leachability of heavy metals are discussed. The main outcome is that the vitrified slag is characterized as inert and stable and can be safely disposed at landfills or used in the construction sector. Finally, the water-cooled slag showed better resistance in relation to heavy metal leachability compared to the air-cooled slag. Copyright © 2011 Elsevier B.V. All rights reserved.

Atmospheric Gaseous Plasma with Large Dimensions

Science.gov (United States)

Korenev, Sergey

2012-10-01

The forming of atmospheric plasma with large dimensions using electrical discharge typically uses the Dielectric Barrier Discharge (DBD). The study of atmospheric DBD was shown some problems related to homogeneous volume plasma. The volume of this plasma determines by cross section and gas gap between electrode and dielectric. The using of electron beam for volume ionization of air molecules by CW relativistic electron beams was shown the high efficiency of this process [1, 2]. The main advantage of this approach consists in the ionization of gas molecules by electrons in longitudinal direction determines by their kinetic energy. A novel method for forming of atmospheric homogeneous plasma with large volume dimensions using ionization of gas molecules by pulsed non-relativistic electron beams is presented in the paper. The results of computer modeling for delivered doses of electron beams in gases and ionization are discussed. The structure of experimental bench with plasma diagnostics is considered. The preliminary results of forming atmospheric plasma with ionization gas molecules by pulsed nanosecond non-relativistic electron beam are given. The analysis of potential applications for atmospheric volume plasma is presented. Reference: [1] S. Korenev. ``The ionization of air by scanning relativistic high power CW electron beam,'' 2002 IEEE International Conference on Plasma Science. May 2002, Alberta, Canada. [2] S. Korenev, I. Korenev. ``The propagation of high power CW scanning electron beam in air.'' BEAMS 2002: 14th International Conference on High-Power Particle Beams, Albuquerque, New Mexico (USA), June 2002, AIP Conference Proceedings Vol. 650(1), pp. 373-376. December 17.

Atmospheric pressure cold plasma as an antifungal therapy

International Nuclear Information System (INIS)

Sun Peng; Wu Haiyan; Sun Yi; Liu Wei; Li Ruoyu; Zhu Weidong; Lopez, Jose L.; Zhang Jue; Fang Jing

2011-01-01

A microhollow cathode based, direct-current, atmospheric pressure, He/O 2 (2%) cold plasma microjet was used to inactive antifungal resistants Candida albicans, Candida krusei, and Candida glabrata in air and in water. Effective inactivation (>90%) was achieved in 10 min in air and 1 min in water. Antifungal susceptibility tests showed drastic reduction of the minimum inhibitory concentration after plasma treatment. The inactivation was attributed to the reactive oxygen species generated in plasma or in water. Hydroxyl and singlet molecular oxygen radicals were detected in plasma-water system by electron spin resonance spectroscopy. This approach proposed a promising clinical dermatology therapy.

Plasma igniter for internal-combustion engines

Science.gov (United States)

Breshears, R. R.; Fitzgerald, D. J.

1978-01-01

Hot ionized gas (plasma) ignites air/fuel mixture in internal combustion engines more effectively than spark. Electromagnetic forces propel plasma into combustion zone. Combustion rate is not limited by flame-front speed.

Improving the efficiency of plasma heat treatment of metals

International Nuclear Information System (INIS)

Gabdrakhmanov, Az T; Israphilov, I H; Galiakbarov, A T; Samigullin, A D; Gabdrakhmanov, Al T

2016-01-01

This paper proposes an effective way of the plasma hardening the surface layer at the expense combined influence of the plasma jet and a cold air flow. After that influence occurs a distinctive by plasma treatment microstructure with increased microhardness (an increase of 35%) and depth. There is proposed an improved design of the vortex tube for receiving the air flow with a temperature of 20 C to - 120C. (paper)

Wind tunnel experiments on flow separation control of an Unmanned Air Vehicle by nanosecond discharge plasma aerodynamic actuation

International Nuclear Information System (INIS)

Chen Kang; Liang Hua

2016-01-01

Plasma flow control (PFC) is a new kind of active flow control technology, which can improve the aerodynamic performances of aircrafts remarkably. The flow separation control of an unmanned air vehicle (UAV) by nanosecond discharge plasma aerodynamic actuation (NDPAA) is investigated experimentally in this paper. Experimental results show that the applied voltages for both the nanosecond discharge and the millisecond discharge are nearly the same, but the current for nanosecond discharge (30 A) is much bigger than that for millisecond discharge (0.1 A). The flow field induced by the NDPAA is similar to a shock wave upward, and has a maximal velocity of less than 0.5 m/s. Fast heating effect for nanosecond discharge induces shock waves in the quiescent air. The lasting time of the shock waves is about 80 μs and its spread velocity is nearly 380 m/s. By using the NDPAA, the flow separation on the suction side of the UAV can be totally suppressed and the critical stall angle of attack increases from 20° to 27° with a maximal lift coefficient increment of 11.24%. The flow separation can be suppressed when the discharge voltage is larger than the threshold value, and the optimum operation frequency for the NDPAA is the one which makes the Strouhal number equal one. The NDPAA is more effective than the millisecond discharge plasma aerodynamic actuation (MDPAA) in boundary layer flow control. The main mechanism for nanosecond discharge is shock effect. Shock effect is more effective in flow control than momentum effect in high speed flow control. (paper)

Direct plasma interaction with living tissue

Science.gov (United States)

Fridman, Gregory

For some time, plasma has been used in medicine to cauterize or cut tissue using heat and mechanical energy. In the recent decade, some researchers around the world have started to investigate how gas jets that pass through thermal plasma can be employed in medicine. This thesis presents the first investigation of biomedical uses of non-thermal plasma discharge which comes in direct contact with living tissue. It is demonstrated that the direct application of non-thermal plasma in air can cause rapid deactivation of bacteria on surfaces of tissues without causing any visible tissue damage. Medical need for such a device is discussed. Construction and operation of various types of non-thermal plasma power supplies and many types of treatment electrodes are presented as well. Application of this plasma to living organisms is shown to be safe from both the electrical perspective and from the biological perspective. Biological safety is revealed through a series of differential skin toxicity trials on human cadaver tissue, live hairless mouse skin tissue, live pig skin tissue, and finally in an open wound model on pigs. Direct non-thermal plasma in air is shown to deactivate bacteria about 100 times faster than indirect application using jets. A series of experiments reveal that this effectiveness is due to the ability of direct discharge to bring charges to tissue surfaces. It is demonstrated that neither ultraviolet (UV) radiation nor neutral active species such as hydroxyl radicals or ozone produced in plasma are responsible for the main effect on bacteria. Although much additional work remains on establishing detailed mechanism by which charges from plasma achieve this effect, the work carried out in this thesis clearly demonstrates that direct application of non-thermal plasma in air can be a very useful tool in medicine.

Radiation pattern of open ended waveguide in air core surrounded by annular plasma column

International Nuclear Information System (INIS)

Sharma, D.R.; Verma, J.S.

1977-01-01

Radiation pattern of open ended waveguide excited in circular symmetric mode (TM 01 ) in an air core having central conductor and surrounded by an annular plasma column is studied. The field distribution at the open end of the waveguide is considered to be equivalent to the vector sum of magnetic current rings of various radii, ranging from the outer radius of the inner conductor to the inner radius of the outer conductor of the waveguide at the open end. The radiation field is obtained as a vector sum of field components due to individual rings of current. Such a configuration gives rise to multiple narrow radiation beams away from the critical angle. (author)

Cross border transport of vitrified residues from France to Germany

International Nuclear Information System (INIS)

Graf, W.; Jussofie, A.

2016-01-01

Until 1994 reprocessing was the only legal way to manage German spent fuel. Since in 1984 the national reprocessing concept was abandoned the reprocessing abroad was the only existing disposal route. With the amendment of the Atomic Energy Act in 2002 spent fuel management changed completely since from 1 June 2005 any delivery of spent fuel to reprocessing plants was prohibited and the direct disposal of spent fuel became mandatory. Until 2005 the total amount of spent fuel to be reprocessed abroad added up to 6080 t HM, 5309 t HM thereof in France. According to the commercial contracts signed between the German utilities and COGEMA, now AREVA NC, in France and BNFL, now INS in UK, and to the intergovernmental agreements concluded between Germany and France or UK the waste generated from reprocessing has to be returned to Germany. The return of high active vitrified waste from La Hague to the interim storage facility at Gorleben was not only demanding from the view of safety ensured by the cask design but especially for security reasons since the Gorleben area served as a target for nuclear opponents from the first transport in 1996 to the latest one in 2010. The protection against sabotage of the railway lines and mass protests needed improved security measures. Special working forces and projects have been set up in France and Germany to cope with this situation. A complex transport organization was necessary to involve all parties in line with the German and French security requirements during transport. All transports have been completed successfully so far thus confirming the efficiency of the applied measures. (author)

Plasma treatment of onychomycosis

Science.gov (United States)

Xiong, Zilan; Roe, Jeff; Grammer, Tim; Him, Yeon-Ho; Graves, David B.

2015-09-01

Onychomycosis or fungal infection of the toenail or fingernail is a common affliction. Approximately 10% of the world's adult population is estimated to suffer from onychomycosis. Current treatment options such as topical creams, oral drugs, or laser treatments are generally limited by a variety of problems. We present results for an alternative onychomycosis treatment scheme using atmospheric pressure cold air plasmas. Using thinned cow hoof as a model nail material, we tested the ability of various plasma sources to act through the model nail to eradicate either bacteria or fungus deposited on the opposite side. Following 20 minute exposure to a surface microdischarge (SMD) device operating in room air, we observed a ~ 2 log reduction of E. coli. A similar result was obtained against T. rubrum after 45 min plasma treatment. NOx species concentration penetrating through the model nail as well as uptake into the nail were measured as a function of nail thickness. We propose that these plasma-generated species, or perhaps their reaction products, are responsible for at least part of the observed anti-microbial effect. We also explore the use of ultraviolet light acting in synergy with plasma-generated chemical species.

Nonthermal plasma technology for organic destruction

International Nuclear Information System (INIS)

Heath, W.O.; Birmingham, J.G.

1995-06-01

Pacific Northwest Laboratory (PNL) is investigating the use of nonthermal, electrically driven plasmas for destroying organic contaminants near ambient temperatures and pressures. Three different plasma systems have been developed to treat organics in air, water, and soil. These systems are the Gas-Phase Corona Reactor (GPCR)III for treating air, the Liquid-Phase Corona Reactor for treating water, and In Situ Corona for treating soils. This presentation focuses on recent technical developments, commercial status, and project costs of OPCR as a cost-effective alternative to other air-purification technologies that are now in use to treat off-gases from site-remediation efforts as well as industrial emissions

Oxygen Plasma Treatment of Rubber Surface by the Atmospheric Pressure Cold Plasma Torch

DEFF Research Database (Denmark)

Lee, Bong-ju; Kusano, Yukihiro; Kato, Nobuko

1997-01-01

adhesive. The adhesion property was improved by treatment of the rubber compound with plasma containing oxygen radicals. Physical and chemical changes of the rubber surface as a result of the plasma treatment were analyzed by field emission scanning electron microscopy (FE-SEM) and fourier transform......A new application of the atmospheric cold plasma torch has been investigated. Namely, the surface treatment of an air-exposed vulcanized rubber compound. The effect of plasma treatment was evaluated by the bondability of the treated rubber compound with another rubber compound using a polyurethane...

Atmospheric plasma surface modifications of electrospun PCL/chitosan/PCL hybrid scaffolds by nozzle type plasma jets for usage of cell cultivation

Energy Technology Data Exchange (ETDEWEB)

Surucu, Seda [Department of Metallurgical and Materials Engineering, Atilim University, Incek, Golbasi, 06836, Ankara (Turkey); Masur, Kai [Leibniz Institute for Plasma Science and Technology (Germany); Turkoglu Sasmazel, Hilal, E-mail: hilal.sasmazel@atilim.edu.tr [Department of Metallurgical and Materials Engineering, Atilim University, Incek, Golbasi, 06836, Ankara (Turkey); Von Woedtke, Thomas; Weltmann, Klaus Dieter [Leibniz Institute for Plasma Science and Technology (Germany)

2016-11-01

Highlights: • Electrospun PCL/chitosan/PCL scaffolds introduced to the literature by us were modified with atmospheric pressure plasma jets. • Plasma was fed into the system with different gas flow rates, time and distances. • Topographical and functional changes were examined by various characterization methods. • Optimum plasma treatment parameters for enhanced topography and functionality were determined. • Electrospun hybrid plasma surface modified samples showed the increased biocompatibility performance of L929 fibroblast cells. - Abstract: This paper reports Ar gas, Ar + O{sub 2}, Ar + O{sub 2} + N{sub 2} gas mixtures and dry air plasma modifications by atmospheric pressure argon driven kINPen and air driven Diener (PlasmaBeam) plasma jets to alter surface properties of three dimensional (3D), electrospun PCL/Chitosan/PCL layer by layer hybrid scaffolds to improve human fibroblast (MRC5) cell attachment and growth. The characterizations of the samples were done by contact angle (CA) measurements, scanning electron microscopy (SEM), X-Ray Photoelectron spectroscopy (XPS) analysis. The results showed that the plasma modification carried out under dry air and Ar + O{sub 2} + N{sub 2} gas mixtures were altered effectively the nanotopography and the functionality of the material surfaces. It was found that the samples treated with Ar + O{sub 2} + N{sub 2} gas mixtures for 1 min and dry air for 9 min have better hydrophilicity 78.9° ± 1.0 and 75.6° ± 0.1, respectively compared to the untreated samples (126.5°). Biocompatibility performance of the scaffolds was determined with alamarBlue (aB) assay and MTT assay methods, Giemsa staining, fluorescence microscope, confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) analyses. The results showed that plasma treated samples increased the hydrophilicity and oxygen functionality and topography of the surfaces significantly, thus affecting the cell viability and proliferation on

Atmospheric plasma surface modifications of electrospun PCL/chitosan/PCL hybrid scaffolds by nozzle type plasma jets for usage of cell cultivation

International Nuclear Information System (INIS)

Surucu, Seda; Masur, Kai; Turkoglu Sasmazel, Hilal; Von Woedtke, Thomas; Weltmann, Klaus Dieter

2016-01-01

Highlights: • Electrospun PCL/chitosan/PCL scaffolds introduced to the literature by us were modified with atmospheric pressure plasma jets. • Plasma was fed into the system with different gas flow rates, time and distances. • Topographical and functional changes were examined by various characterization methods. • Optimum plasma treatment parameters for enhanced topography and functionality were determined. • Electrospun hybrid plasma surface modified samples showed the increased biocompatibility performance of L929 fibroblast cells. - Abstract: This paper reports Ar gas, Ar + O_2, Ar + O_2 + N_2 gas mixtures and dry air plasma modifications by atmospheric pressure argon driven kINPen and air driven Diener (PlasmaBeam) plasma jets to alter surface properties of three dimensional (3D), electrospun PCL/Chitosan/PCL layer by layer hybrid scaffolds to improve human fibroblast (MRC5) cell attachment and growth. The characterizations of the samples were done by contact angle (CA) measurements, scanning electron microscopy (SEM), X-Ray Photoelectron spectroscopy (XPS) analysis. The results showed that the plasma modification carried out under dry air and Ar + O_2 + N_2 gas mixtures were altered effectively the nanotopography and the functionality of the material surfaces. It was found that the samples treated with Ar + O_2 + N_2 gas mixtures for 1 min and dry air for 9 min have better hydrophilicity 78.9° ± 1.0 and 75.6° ± 0.1, respectively compared to the untreated samples (126.5°). Biocompatibility performance of the scaffolds was determined with alamarBlue (aB) assay and MTT assay methods, Giemsa staining, fluorescence microscope, confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) analyses. The results showed that plasma treated samples increased the hydrophilicity and oxygen functionality and topography of the surfaces significantly, thus affecting the cell viability and proliferation on/within scaffolds.

Waste acceptance and waste loading for vitrified Oak Ridge tank waste

International Nuclear Information System (INIS)

Harbour, J.R.; Andrews, M.K.

1997-01-01

The Office of Science and Technology of the DOE has funded a joint project between the Oak Ridge National Laboratory (ORNL) and the Savannah River Technology Center (SRTC) to evaluate vitrification and grouting for the immobilization of sludge from ORNL tank farms. The radioactive waste is from the Gunite and Associated Tanks (GAAT), the Melton Valley Storage Tanks (MVST), the Bethel Valley Evaporator Service Tanks (BVEST), and the Old Hydrofractgure Tanks (OHF). Glass formulation development for sludge from these tanks is discussed in an accompanying article for this conference (Andrews and Workman). The sludges contain transuranic radionuclides at levels which will make the glass waste form (at reasonable waste loadings) TRU. Therefore, one of the objectives for this project was to ensure that the vitrified waste form could be disposed of at the Waste Isolation Pilot Plant (WIPP). In order to accomplish this, the waste form must meet the WIPP Waste Acceptance Criteria (WAC). An alternate pathway is to send the glass waste forms for disposal at the Nevada Test Site (NTS). A sludge waste loading in the feed of 6 wt percent will lead to a waste form which is non-TRU and could potentially be disposed of at NTS. The waste forms would then have to meet the requirements of the NTS WAC. This paper presents SRTC''s efforts at demonstrating that the glass waste form produced as a result of vitrification of ORNL sludge will meet all the criteria of the WIPP WAC or NTS WAC

The PERC trademark process: Existing and potential applications for induction coupled plasma technology in hazardous and radioactive waste treatment

International Nuclear Information System (INIS)

Blutke, A.S.; Vavruska, J.S.; Serino, J.F.

1996-01-01

Plasma Technology, Inc. (PTI), a Santa Fe, New Mexico corporation has developed the Plasma Energy Recycle and Conversion (PERC)trademark treatment process as a safe and environmentally clean alternative to conventional thermal destruction technologies. The PERC trademark treatment process uses as its heat source an advanced Induction Coupled Plasma (ICP) torch connected to a reaction chamber system with an additional emission control system. For example, organic-based gas, liquid, slurry, and/or solid waste streams can be converted into usable or even salable products while residual emissions are reduced to an absolute minimum. In applications for treatment of hazardous and radioactive waste streams, the PERC system could be used for destruction of the hazardous organic constituents and/or significant waste volume reduction while capturing the radioactive fraction in a non-leachable form. Like Direct Current (DC) and Alternating Current (AC) arc plasma systems, ICP torches offer sufficient energy to decompose, melt and/or vitrify any waste stream. The decision for an arc plasma or an IC plasma system has to be made on a case by case evaluation and is highly dependent on the specific waste stream's form and composition. Induction coupled plasma technology offers one simple, but significant difference compared to DC or AC arc plasma systems: the ICP torch is electrodeless. To date, enormous research effort has been spent to improve the lifetime of electrodes and the effectiveness of related cooling systems. Arc plasma systems are established in research laboratories worldwide and are approaching a broad use in commercial applications. ICP technology has been improved relatively recently, but nowadays offers complete new and beneficial approaches in the field of waste conversion and treatment

A uniform laminar air plasma plume with large volume excited by an alternating current voltage

Science.gov (United States)

Li, Xuechen; Bao, Wenting; Chu, Jingdi; Zhang, Panpan; Jia, Pengying

2015-12-01

Using a plasma jet composed of two needle electrodes, a laminar plasma plume with large volume is generated in air through an alternating current voltage excitation. Based on high-speed photography, a train of filaments is observed to propagate periodically away from their birth place along the gas flow. The laminar plume is in fact a temporal superposition of the arched filament train. The filament consists of a negative glow near the real time cathode, a positive column near the real time anode, and a Faraday dark space between them. It has been found that the propagation velocity of the filament increases with increasing the gas flow rate. Furthermore, the filament lifetime tends to follow a normal distribution (Gaussian distribution). The most probable lifetime decreases with increasing the gas flow rate or decreasing the averaged peak voltage. Results also indicate that the real time peak current decreases and the real time peak voltage increases with the propagation of the filament along the gas flow. The voltage-current curve indicates that, in every discharge cycle, the filament evolves from a Townsend discharge to a glow one and then the discharge quenches. Characteristic regions including a negative glow, a Faraday dark space, and a positive column can be discerned from the discharge filament. Furthermore, the plasma parameters such as the electron density, the vibrational temperature and the gas temperature are investigated based on the optical spectrum emitted from the laminar plume.

Energy coupling to the plasma in repetitive nanosecond pulse discharges

International Nuclear Information System (INIS)

Adamovich, Igor V.; Nishihara, Munetake; Choi, Inchul; Uddi, Mruthunjaya; Lempert, Walter R.

2009-01-01

A new analytic quasi-one-dimensional model of energy coupling to nanosecond pulse discharge plasmas in plane-to-plane geometry has been developed. The use of a one-dimensional approach is based on images of repetitively pulsed nanosecond discharge plasmas in dry air demonstrating that the plasma remains diffuse and uniform on a nanosecond time scale over a wide range of pressures. The model provides analytic expressions for the time-dependent electric field and electron density in the plasma, electric field in the sheath, sheath boundary location, and coupled pulse energy. The analytic model predictions are in very good agreement with numerical calculations. The model demonstrates that (i) the energy coupled to the plasma during an individual nanosecond discharge pulse is controlled primarily by the capacitance of the dielectric layers and by the breakdown voltage and (ii) the pulse energy coupled to the plasma during a burst of nanosecond pulses decreases as a function of the pulse number in the burst. This occurs primarily because of plasma temperature rise and resultant reduction in breakdown voltage, such that the coupled pulse energy varies approximately proportionally to the number density. Analytic expression for coupled pulse energy scaling has been incorporated into the air plasma chemistry model, validated previously by comparing with atomic oxygen number density measurements in nanosecond pulse discharges. The results of kinetic modeling using the modified air plasma chemistry model are compared with time-resolved temperature measurements in a repetitively pulsed nanosecond discharge in air, by emission spectroscopy, and purely rotational coherent anti-Stokes Raman spectroscopy showing good agreement.

Pulsed-Plasma Disinfection of Water Containing Escherichia coli

Science.gov (United States)

Satoh, Kohki; MacGregor, Scott J.; Anderson, John G.; Woolsey, Gerry A.; Fouracre, R. Anthony

2007-03-01

The disinfection of water containing the microorganism, Escherichia coli (E. coli) by exposure to a pulsed-discharge plasma generated above the water using a multineedle electrode (plasma-exposure treatment), and by sparging the off-gas of the pulsed plasma into the water (off-gas-sparging treatment), is performed in the ambient gases of air, oxygen, and nitrogen. For the off-gas-sparging treatment, bactericidal action is observed only when oxygen is used as the ambient gas, and ozone is found to generate the bactericidal action. For the plasma-exposure treatment, the density of E. coli bacteria decreases exponentially with plasma-exposure time for all the ambient gases. It may be concluded that the main contributors to E. coli inactivation are particle species produced by the pulsed plasma. For the ambient gases of air and nitrogen, the influence of acidification of the water in the system, as a result of pulsed-plasma exposure, may also contribute to the decay of E. coli density.

Photocatalytic activity of silver oxide capped Ag nanoparticles constructed by air plasma irradiation

Science.gov (United States)

Fang, Yingcui; Wu, Qingmeng; Li, Huanhuan; Zhang, Bing; Yan, Rong; Chen, Junling; Sun, Mengtao

2018-04-01

We construct a kind of structure of silver oxide capped silver nanoparticles (AgNPs) by cost-efficient air plasma irradiation, and study its visible-light driven photocatalytic activity (PA). By controlling the oxidization time, the relationship between the intensity of the localized surface plasmon resonance (LSPR) and the PA is well established. The PA reaches the maximum when the LSPR of AgNPs is nearly completely damped (according to absorption spectra); however, under this condition, the LSPR still works, confirmed with the high efficient selective transformation of p-Aminothiophenol (PATP) to p, p'-dimercaptoazobenzene (DMAB) under visible light. The mechanism of the LSPR damping induced PA improvement is discussed. We not only provide a cost-efficient approach to construct a LSPR strong damping structure but also promote the understanding of LSPR strong damping and its relationship with photocatalysis.

Surface modification of polyethylene by plasma; Modificacion superficial de polietileno por plasma

Energy Technology Data Exchange (ETDEWEB)

Colin O, E

2003-07-01

The products made of polyethylene (PE) go from construction materials, electric insulating until packing material. The films for bags and pack occupy 83.6% of the distribution of the market of PE approximately. The enormous quantity of PE that is generated by its indiscriminate use brings as consequence a deterioration to the atmosphere, due to the long life that they present as waste. This work is a study on the modification of low density polyethylene films. In this type of thin materials, the changes in the surface meet with largely on the conformation of the rest of the material. To induce changes that modify the surface of PE, plasmas were used with reactive atmospheres of air, oxygen and nitrogen. The experimentation that was carries out went to introduce the PE to a cylindrical reactor where it was generated the plasma of air, oxygen and nitrogen to different times of exposure. After having carried out the exposure to the plasma, it was found that in the polyethylene it modifies their morphology, crystallinity, hydrophobicity, composition and electric conductivity. The analytical techniques that were used to characterize later to the polyethylene of being in contact with the plasma were: X-ray diffraction, Scanning Electron Microscopy, Infrared spectroscopy, Electric conductivity, Angle of contact and finally Thermal Gravimetric Analysis. The content of this work it is presented in five chapters: In the chapter 1 there are presented some general concepts of plasma and of the one polymer in study PE. In the chapter 2 it is made a general revision on modification of surfaces, as well as the properties that were modified in polymeric materials that were exposed to plasma in previous works. In the chapter 3 the experimental part and the conditions used are described in the modification of the PE. Also in this chapter a brief description it is made of the used characterization techniques. The results and discussion are presented in the chapter 4. These results

Storage of HLW in engineered structures: air-cooled and water-cooled concepts

International Nuclear Information System (INIS)

Ahner, S.; Dekais, J.J.; Puttke, B.; Staner, P.

1981-01-01

A comparative study on an air-cooled and a water-cooled intermediate storage of vitrified, highly radioactive waste (HLW) in overground installations has been performed by Nukem and Belgonucleaire respectively. In the air-cooled storage concept the decay heat from the storage area will be removed using natural convection. In the water-cooled storage concept the decay heat is carried off by a primary and secondary forced-cooling system with redundant and diverse devices. The safety study carried out by Nukem used a fault tree method. It shows that the reliability of the designed water-cooled system is very high and comparable to the inherent, safe, air-cooled system. The impact for both concepts on the environment is determined by the release route, but even during accident conditions the release is far below permissible limits. The economic analysis carried out by Belgonucleaire shows that the construction costs for both systems do not differ very much, but the operation and maintenance costs for the water-cooled facility are higher than for the air cooled facility. The result of the safety and economic analysis and the discussions with the members of the working group have shown some possible significant modifications for both systems, which are included in this report. The whole study has been carried out using certain national criteria which, in certain Member States at least, would lead to a higher standard of safety than can be justified on any social, political or economic grounds

Atmospheric plasma surface modifications of electrospun PCL/chitosan/PCL hybrid scaffolds by nozzle type plasma jets for usage of cell cultivation

Science.gov (United States)

Surucu, Seda; Masur, Kai; Turkoglu Sasmazel, Hilal; Von Woedtke, Thomas; Weltmann, Klaus Dieter

2016-11-01

This paper reports Ar gas, Ar + O2, Ar + O2 + N2 gas mixtures and dry air plasma modifications by atmospheric pressure argon driven kINPen and air driven Diener (PlasmaBeam) plasma jets to alter surface properties of three dimensional (3D), electrospun PCL/Chitosan/PCL layer by layer hybrid scaffolds to improve human fibroblast (MRC5) cell attachment and growth. The characterizations of the samples were done by contact angle (CA) measurements, scanning electron microscopy (SEM), X-Ray Photoelectron spectroscopy (XPS) analysis. The results showed that the plasma modification carried out under dry air and Ar + O2 + N2 gas mixtures were altered effectively the nanotopography and the functionality of the material surfaces. It was found that the samples treated with Ar + O2 + N2 gas mixtures for 1 min and dry air for 9 min have better hydrophilicity 78.9° ± 1.0 and 75.6° ± 0.1, respectively compared to the untreated samples (126.5°). Biocompatibility performance of the scaffolds was determined with alamarBlue (aB) assay and MTT assay methods, Giemsa staining, fluorescence microscope, confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) analyses. The results showed that plasma treated samples increased the hydrophilicity and oxygen functionality and topography of the surfaces significantly, thus affecting the cell viability and proliferation on/within scaffolds.

Weakly Ionized Plasmas in Hypersonics: Fundamental Kinetics and Flight Applications

International Nuclear Information System (INIS)

Macheret, Sergey

2005-01-01

The paper reviews some of the recent studies of applications of weakly ionized plasmas to supersonic/hypersonic flight. Plasmas can be used simply as means of delivering energy (heating) to the flow, and also for electromagnetic flow control and magnetohydrodynamic (MHD) power generation. Plasma and MHD control can be especially effective in transient off-design flight regimes. In cold air flow, nonequilibrium plasmas must be created, and the ionization power budget determines design, performance envelope, and the very practicality of plasma/MHD devices. The minimum power budget is provided by electron beams and repetitive high-voltage nanosecond pulses, and the paper describes theoretical and computational modeling of plasmas created by the beams and repetitive pulses. The models include coupled equations for non-local and unsteady electron energy distribution function (modeled in forward-back approximation), plasma kinetics, and electric field. Recent experimental studies at Princeton University have successfully demonstrated stable diffuse plasmas sustained by repetitive nanosecond pulses in supersonic air flow, and for the first time have demonstrated the existence of MHD effects in such plasmas. Cold-air hypersonic MHD devices are shown to permit optimization of scramjet inlets at Mach numbers higher than the design value, while operating in self-powered regime. Plasma energy addition upstream of the inlet throat can increase the thrust by capturing more air (Virtual Cowl), or it can reduce the flow Mach number and thus eliminate the need for an isolator duct. In the latter two cases, the power that needs to be supplied to the plasma would be generated by an MHD generator downstream of the combustor, thus forming the 'reverse energy bypass' scheme. MHD power generation on board reentry vehicles is also discussed

Preliminary studies on a plasma focus opening switch

Energy Technology Data Exchange (ETDEWEB)

Wong, C S; Moo, S P; Singh, J P [Univ. of Malaya, Kuala Lumpur (Malaysia). Physics Dept., Plasma Research Laboratory; Choi, P [Ecole Polytechnique, Palaiseau (France). Laboratoire de Physique des Milieux Ionises

1997-12-31

The small plasma focus device UNU/ICTP PFF has been modified to assess the operation of a plasma focus based long conduction (> 2 {mu}s) opening switch, with a plasma filled diode as the load. The UNU/ICTP PFF is a Mather type plasma focus device powered by a single 15 kV, 30 {mu}F capacitor delivering a peak current of 150 kA when discharged at 15 kV. The device has been optimized for reproducible focusing in various gases including deuterium, argon, carbon dioxide, helium as well as in air. In particular, the optimum operating pressure for air is between 0.5 to 1.1 mbar, whereas for argon it is between 0.3 to 3 mbar. For the operation of the UNU/ICTP PFF as an opening switch, the electrode geometry is modified to redirect the plasma motion at the end of the axial rundown phase to avoid the normal plasma focus action, and the operating regime is shifted to low pressure to favour plasma opening switch action. With air as the working gas, pressure as low as 10{sup -3} mbar was tested. At such a low pressure, a set of 12 plasma injection cable guns is used to initiate breakdown of the discharge. The design and operating principle is presented and some preliminary results obtained on the operational characteristics of this device are discussed. (author). 5 figs., 4 refs.

Nippon paint atmospheric plasma system

International Nuclear Information System (INIS)

Tsuchiya, Y.; Akutsu, K.

1996-01-01

An invitational plasma systems which are able to generate the wide and stable plasma (discharge distance 30 cm length, discharge electrode length max. 16 m) under normal air and pressure by using and narrow wave-form of pulse voltage has been developed. Its technical outline and some applied examples are reported

Plasma treatment of polyethersulfone membrane for benzene removal from water by air gap membrane distillation.

Science.gov (United States)

Pedram, Sara; Mortaheb, Hamid Reza; Arefi-Khonsari, Farzaneh

2018-01-01

In order to obtain a durable cost-effective membrane for membrane distillation (MD) process, flat sheet polyethersulfone (PES) membranes were modified by an atmospheric pressure nonequilibrium plasma generated using a dielectric barrier discharge in a mixture of argon and hexamethyldisiloxane as the organosilicon precursor. The surface properties of the plasma-modified membranes were characterized by water contact angle (CA), liquid entry pressure, X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. The water CA of the membrane was increased from 64° to 104° by depositing a Si(CH 3 )-rich thin layer. While the pristine PES membrane was not applicable in the MD process, the modified PES membrane could be applied for the first time in an air gap membrane distillation setup for the removal of benzene as a volatile organic compound from water. The experimental design using central composite design and response surface methodology was applied to study the effects of feed temperature, concentration, and flow rate as well as their binary interactions on the overall permeate flux and separation factor. The separation factor and permeation flux of the modified PES membrane at optimum conditions were comparable with those of commercial polytetrafluoroethylene membrane.

Modification of surface characteristic and tribo-electric properties of polymers by DBD plasma in atmospheric air

Science.gov (United States)

Bekkara, Mohammed Fethi; Dascalescu, Lucien; Benmimoun, Youcef; Zeghloul, Thami; Tilmatine, Amar; Zouzou, Noureddine

2018-01-01

The aim of this paper is to quantify the effects of dielectric barrier discharge (DBD) exposure on the physico-chemical and tribo-electric properties of polymers. The study was conducted in atmospheric air on polypropylene, polyethylene and polyvinyl-chloride. These three types of polymers are widely used in industry. The polymers were characterized by means of an optical profilometer, a fourier-transform infrared (FTIR) spectrometer and an electric charge measurement system. The latter is composed of a Faraday pail connected to an electrometer. The profilometer analyses showed that the DBD plasma treatment has increased the surface roughness of the three polymers. FTIR revealed that oxygen atoms and polar groups were grafted on their surfaces, thereby conferring them a hydrophilic character. The short (2 sec) DBD plasma treatment has considerably improved the electrostatic charge acquired by the polymers during electrostatic tribo-charging, while longer exposures conferred the polymer anti-static properties and decreased its tribo-charging capability. The correlation between the results of the physico-chemical analyses and the tribo-electric behavior has been discussed.

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

International Nuclear Information System (INIS)

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

2013-01-01

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

Microwave Production of Steady State Large Volume Air Plasmas

National Research Council Canada - National Science Library

Brandenburg, John

1999-01-01

...) and these plasmas persist for hundreds of milliseconds after power is turned off. These plasmas can be made in an inexpensive and easy to build apparatus based around a microwave oven operating at approximately 1kW and 2.45GHz...

Development of a low-cost inductively coupled argon plasma

International Nuclear Information System (INIS)

Ripson, P.A.M.

1983-01-01

The aim of this investigation is to drastically reduce running costs of an inductively coupled plasma. This is done by reducing the argon consumption from 20 l/min to about 1 l/min. First, a sample introduction system operating on 0.1 l/min of carrier argon is described. This system ensures a high ratio of plasma argon and carrier argon even at the low total argon consumptions intended. Next, the developed low consumption plasma is presented. In the proposed design, air is blown perpendicularly against the outside of the torch. A different coil has been developed to make air-cooling efficient. Preliminary data on coupling efficiency for the air-cooled plasma are presented. A similarly low argon consumption has been achieved with water as an external coolant medium. It is concluded that a cheaper alternative to the current ICP has become available. (Auth.)

Ozone synthesis improves by increasing number density of plasma channels and lower voltage in a nonthermal plasma

Science.gov (United States)

Arif Malik, Muhammad; Hughes, David

2016-04-01

Improvements in ozone synthesis from air and oxygen by increasing the number density of plasma channels and lower voltage for the same specific input energy (SIE) were explored in a nonthermal plasma based on a sliding discharge. The number of plasma channels and energy per pulse increased in direct proportion to the increase in the effective length of the anode (the high voltage electrode). Decreasing the discharge gap increased the energy per pulse for the same length and allowed the installation of more electrode pairs in the same space. It allowed the increase of the number of plasma channels in the same space to achieve the same SIE at a lower peak voltage with less energy per plasma channel. The ozone concentration gradually increased to ~1500 ppmv (140 to 50 g kWh-1) from air and to ~6000 ppmv (400 to 200 g kWh-1) from oxygen with a gradual increase in the SIE to ~200 J L-1, irrespective of the variations in electrode geometry, applied voltage or flow rate of the feed gas. A gradual increase in SIE beyond 200 J L-1 gradually increased the ozone concentration to a certain maximum value followed by a decline, but the rate of increase and the maximum value was higher for the greater number of plasma channels and lower peak voltage combination. The maximum ozone concentration was ~5000 ppmv (~30 g kWh-1) from air and ~22 000 ppmv (~80 g kWh-1) from oxygen. The results are explained on the basis of characteristics of the plasma and ozone synthesis mechanism.

Numerical and experimental study on a pulsed-dc plasma jet

Science.gov (United States)

Liu, X. Y.; Pei, X. K.; Lu, X. P.; Liu, D. W.

2014-06-01

A numerical and experimental study of plasma jet propagation in a low-temperature, atmospheric-pressure, helium jet in ambient air is presented. A self-consistent, multi-species, two-dimensional axially symmetric plasma model with detailed finite-rate chemistry of helium-air mixture composition is used to provide insights into the propagation of the plasma jet. The obtained simulation results suggest that the sheath forms near the dielectric tube inner surface and shields the plasma channel from the tube surface. The strong electric field at the edge of the dielectric field enhances the ionization in the air mixing layer; therefore, the streamer head becomes ring-shaped when the streamer runs out of the tube. The avalanche-to-streamer transition is the main mechanism of streamer advancement. Penning ionization dominates the ionization reactions and increases the electrical conductivity of the plasma channel. The simulation results are supported by experimental observations under similar discharge conditions.

Plasma igniter for internal combustion engine

Science.gov (United States)

Fitzgerald, D. J.; Breshears, R. R. (Inventor)

1978-01-01

An igniter for the air/fuel mixture used in the cylinders of an internal combustion engine is described. A conventional spark is used to initiate the discharge of a large amount of energy stored in a capacitor. A high current discharge of the energy in the capacitor switched on by a spark discharge produces a plasma and a magnetic field. The resultant combined electromagnetic current and magnetic field force accelerates the plasma deep into the combustion chamber thereby providing an improved ignition of the air/fuel mixture in the chamber.

Reevaluation Of Vitrified High-Level Waste Form Criteria For Potential Cost Savings At The Defense Waste Processing Facility

International Nuclear Information System (INIS)

Ray, J. W.; Marra, S. L.; Herman, C. C.

2013-01-01

At the Savannah River Site (SRS) the Defense Waste Processing Facility (DWPF) has been immobilizing SRS's radioactive high level waste (HLW) sludge into a durable borosilicate glass since 1996. Currently the DWPF has poured over 3,500 canisters, all of which are compliant with the U. S. Department of Energy's (DOE) Waste Acceptance Product Specifications for Vitrified High-Level Waste Forms (WAPS) and therefore ready to be shipped to a federal geologic repository for permanent disposal. Due to DOE petitioning to withdraw the Yucca Mountain License Application (LA) from the Nuclear Regulatory Commission (NRC) in 2010 and thus no clear disposal path for SRS canistered waste forms, there are opportunities for cost savings with future canister production at DWPF and other DOE producer sites by reevaluating high-level waste form requirements and compliance strategies and reducing/eliminating those that will not negatively impact the quality of the canistered waste form

Plasma recovery after various events in HT-7 superconducting tokamak

International Nuclear Information System (INIS)

Hu, J.S.; Li, J.G.

2008-01-01

Normal plasma recoveries after various events, such as after shutdown, various boronization, oxidation and large air leak, were investigated in the 2007 campaign of HT-7. Plasma recoveries, including disruptive plasmas, would depend on the wall status, such as impurities content and hydrogen retention. After shutdown or air leak, impurities made plasma recovery very difficult. After boronization, plasma recoveries would depend on the procedures of the boronization (C 2 B 10 H 12 ). After oxidation, boronization would effectively suppress impurities and would be beneficial for plasma recovery. ICRF cleanings in various working gases, such as He and D 2 , would be useful for impurities and hydrogen removal. This research is important for effective operation of HT-7 and would be useful for EAST and ITER operations.

Comparison of the developmental potential of 2-week-old preantral follicles derived from vitrified ovarian tissue slices, vitrified whole ovaries and vitrified/transplanted newborn mouse ovaries using the metal surface method

Directory of Open Access Journals (Sweden)

Hsu Kung-Hao

2008-04-01

comparing 14-day old ovarian tissue (ovarian tissue slices and whole ovaries and whole newborn ovaries vitrified in 6 μl droplet, lower success rates of antral-like cavity formation and COCs collection were found in the whole ovaries group. Conclusion Our results suggest that the metal plate surface vitrification method is an appropriate and convenient method for cryopreservation of mouse ovaries and preantral follicles. The droplet volume of vitrification solution in 2 μl and 6 μl can be an option.

Transfer shuttle for vitrified residue canisters control of risks associated with external exposure and heat release

Energy Technology Data Exchange (ETDEWEB)

BIndel, L.; Gamess, A.; Lejeune, E.; Cellier, P.; Maillard, A. [SGN Reseau Eurisys, 78 - Saint Quentin (France)

1998-07-01

In the La Hague COGEMA's plant area, nuclear residue isolated by reprocessing are transported by means of specific transfer shuttles between the different processing and/or conditioning facilities and the storage ones. These shuttles are designed by reference to the applicable dose equivalent rate (DER) limits for transport on the site and the thermal behavior limitations of certain mechanical components which guarantee the containment of the transported waste. This paper describes and example of a study conducted on a transfer shuttle for vitrified residue canisters. Concerning the control of risks associated with external exposure and with heat releases, these were handled by the 'Shielding-Criticality-Dispersion' and 'process Modelling and Simulation' Sections of the Technical Division of SGN. The dose profiles around the shuttle, as a function of the shielding heterogeneities and possible radiation leakage, as well as the thermal fields within the shuttle, were calculated using 3D models. These design studies ultimately helped to select and validate the optimal solutions. (authors)

Test of 134Cs, 85,89Sr leaching rate in a resemble vitrifiable cement waste form

International Nuclear Information System (INIS)

Lin Meiqiong; Wei Feng; Yin Qi; Fan Xianhua; Xu Shengli; Li Yongde

2003-01-01

A novel material--resemble vitrifiable cement for conditioning low and mediate level radioactive waste has been developed. Waste form has been characterized for their physical and chemical performance, phase composition. The cement formulation has been patented. In this experiment the cement is mixed with simulated wastes spiked with 134 Cs and 85,89 Sr by 5 min at least. The Ratio of the waste to the cement is 0.45-0.55. The mixture is packed into cylindrical molds which has the same dimension of diameter and height . The grouts are cured for a period of 28 d in a room temperature curing chamber at an atmospheric pressure. The cured waste form is then completely immersed into deionized water. According to standard GB7023-86, leaching rate of 134 Cs and 85,89 Sr are measured. The result shows that the leaching rate of the species 134 Cs and 85,89 Sr is to be on the order 10 -4 and 10 -5 on the 42 d immersion, respectively and is better than that of commercial cement

Study on the effects of physical plasma on in-vitro cultivates cells; Untersuchungen zum Einfluss von physikalischem Plasma auf in vitro kultivierte Zellen

Energy Technology Data Exchange (ETDEWEB)

Strassenburg, Susanne

2014-03-15

This study focused on the interactions of non thermal atmospheric pressure plasma on in vitro cultured keratinocytes (HaCaT keratinocytes) and melanoma cells (MV3). Three different plasma sources were used: a plasma jet (kINPen 09), a surface DBD (dielectric barrier discharge) and a volume DBD. For analyzing basic effects of plasma on cells, influence of physical plasma on viability, on DNA and on induction of ROS were investigated. Following assays were used: -- Viability: - neutral red uptake assay, cell counting (number of viable cells, cell integrity) - BrdU assay (proliferation) - Annexin V and propidium iodide staining, flow cytometry (induction of apoptosis), -- DNA: - alkaline comet assay (detection of DNA damage) - staining of DNA with propidium iodide, flow cytometry (cell cycle analysis), -- ROS: - H2DCFDA assay, flow cytometry (detection of ROS-positive cells). In addition to the effects which where induced by the plasma sources, the influence of the plasma treatment regime (direct, indirect and direct with medium exchange), the working gas (argon, air) and the surrounding liquids (cell culture medium: RPMI, IMDM; buffer solutions: HBSS, PBS) on the extent of the plasma cell effects were investigated. All plasma sources induced treatment time-dependent effects in HaCaT keratinocytes and melanoma cells (MV3): - loss of viable cells and reduced proliferation - induction of apoptosis after the longest treatment times - DNA damage 1 h after plasma treatment, 24 h after plasma treatment DNA damage was present only after the longest treatment times, evidence for DNA damage repair - due to accumulation of cells in G2/M phase, cell count in G1 phase (24 h) is lower - increase of ROS-positive cells 1 h and 24 h after plasma treatment. It was shown that cells which were cultured in RPMI showed stronger effects (stronger loss of viability and more DNA damage) than cells which were cultured in IMDM. Also plasma-treated buffer solutions (HBSS, PBS) induced DNA

Massachusetts Institute of Technology Lincoln Laboratory Facilities Replacement on Hanscom Air Force Base Phase 1 Final Environmental Assessment

Science.gov (United States)

2014-07-24

Service UST Underground Storage Tank VC Vitrified Clay VOCs Volatile Organic Compounds W Watts 1 1.0 PURPOSE AND NEED FOR ACTION 1.1 INTRODUCTION The...discharged to sanitary drain and the solids slurry is hauled off site for disposal Fluoride drain: welded stainless steel drain piping from wet...diameter vitrified clay (VC) gravity sewer collection pipe, flowing north/northeast to the upper pumping station at Building 1306, is located within the

Surface modification of thermoplastic poly(vinyl alcohol)/saponite nanocomposites via surface-initiated atom transfer radical polymerization enhanced by air dielectric discharges barrier plasma treatment

International Nuclear Information System (INIS)

Zhen Weijun; Lu Canhui

2012-01-01

To improve the water resistance of thermoplastic poly(vinyl alcohol)/saponite nanocomposites (TPVA), a simple two-step method was developed for the covalent immobilization of atom transfer radical polymerization (ATRP) initiators on the TPVA surfaces enhanced by air dielectric barrier discharges (DBD) plasma treatment, and hydrophobic poly(methyl methacrylate) (PMMA) brushes were then grafted onto the surface of TPVA via surface-initiated atom transfer radical polymerization (SI-ATRP). The chemical composition, morphology and hydrophobicity of the modified TPVA surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. The water resistance of the surface-functionalized PMMA was evaluated by the contact angle and water adsorption method. It was shown that air DBD plasma treatment activated the TPVA surface and accelerated the immobilization of ATRP initiator on the TPVA surface. Compared with TPVA control, TPVA modified by SI-ATRP can be grafted well-defined and covalently tethered network PMMA brushes onto the surface and the hydrophobicity of TPVA were significantly enhanced.

DIAGNOSTICS OF HYBRID WATER/ARGON THERMAL PLASMA JET WITH WATER, ETHANOL AND THEIR MIXTURE INJECTION TO PLASMA

Czech Academy of Sciences Publication Activity Database

Hlína, Michal; Mašláni, Alan; Medřický, Jan; Kotlan, Jiří; Mušálek, Radek; Hrabovský, Milan

2016-01-01

Roč. 3, č. 2 (2016), s. 62-65 ISSN 2336-2626. [SPPT 2016 - 27th Symposium on Plasma Physics and Technology/27./. Prague, 20.06.2016-23.06.2016] R&D Projects: GA ČR GA15-12145S Institutional support: RVO:61389021 Keywords : plasma spraying * suspension * enthalpy probe * spectroscopy * air entrainment Subject RIV: BL - Plasma and Gas Discharge Physics http://ppt.fel.cvut.cz/

Frugal Biotech Applications of Low-Temperature Plasma.

Science.gov (United States)

Machala, Zdenko; Graves, David B

2017-09-01

Gas discharge low-temperature air plasma can be utilized for a variety of applications, including biomedical, at low cost. We term these applications 'frugal plasma' - an example of frugal innovation. We demonstrate how simple, robust, low-cost frugal plasma devices can be used to safely disinfect instruments, surfaces, and water. Copyright © 2017 Elsevier Ltd. All rights reserved.

Thermal fatigue behavior of thermal barrier coatings by air plasma spray

Energy Technology Data Exchange (ETDEWEB)

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

2008-06-15

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

Control of Reactive Species Generated by Low-frequency Biased Nanosecond Pulse Discharge in Atmospheric Pressure Plasma Effluent

Science.gov (United States)

Takashima, Keisuke; Kaneko, Toshiro

2016-09-01

The control of hydroxyl radical and the other gas phase species generation in the ejected gas through air plasma (air plasma effluent) has been experimentally studied, which is a key to extend the range of plasma treatment. Nanosecond pulse discharge is known to produce high reduced electric field (E/N) discharge that leads to efficient generation of the reactive species than conventional low frequency discharge, while the charge-voltage cycle in the low frequency discharge is known to be well-controlled. In this study, the nanosecond pulse discharge biased with AC low frequency high voltage is used to take advantages of these discharges, which allows us to modulate the reactive species composition in the air plasma effluent. The utilization of the gas-liquid interface and the liquid phase chemical reactions between the modulated long-lived reactive species delivered from the air plasma effluent could realize efficient liquid phase chemical reactions leading to short-lived reactive species production far from the air plasma, which is crucial for some plasma agricultural applications.

Study of plasma-wall interactions in Tore-supra; Etude des phenomenes d'interaction plasma/paroi dans Tore Supra

Energy Technology Data Exchange (ETDEWEB)

Ruggieri, R

2000-01-01

In tokamaks the interaction between wall and plasma generates impurities that affect the thermonuclear fusion. This thesis is divided into 2 parts. The first part describes the physico-chemical processes that are involved in chemical erosion, the second part deals with the study of the wear of Tore-supra's walls due to chemical erosion. Chapter 1 presents the wall-plasma interaction and reviews the different processes between plasma and carbon that occur in Tore-supra. Chapter 2 considers the various crystallographic and electronic structures of the carbon that interferes with Tore-supra plasma, the evolution of these structures during irradiation and their temperature dependence are studied. Chapter 3 presents a crystallo-chemical study of graphite samples that have undergone different surface treatments: ionic bombardment, annealing and air exposure. This experimental study has been performed by using energy-loss spectroscopy. It is shown that air exposure modifies the crystallo-chemical structure of surfaces, so it is necessary to prevent air from contaminating wall samples from Tore-supra. Chapter 4 presents a parametric study of chemical erosion rate of plasma facing components (LPM) of Tore-supra. A relation such as Y{sub cd4}{alpha}{gamma}{sup -0.1} gives a good agreement for chemical erosion rate between measurements and the numerical values of the simulation. (A.C.)

Surface modification of polyvinyl alcohol/malonic acid nanofibers by gaseous dielectric barrier discharge plasma for glucose oxidase immobilization

International Nuclear Information System (INIS)

Afshari, Esmail; Mazinani, Saeedeh; Ranaei-Siadat, Seyed-Omid; Ghomi, Hamid

2016-01-01

Highlights: • We fabricated polyvinyl alcohol/malonic acid nanofibers using electrospinning. • The surface nanofibers were modified by gaseous (air, nitrogen, CO_2 and argon) dielectric barrier discharge. • Among them, air plasma had the most significant effect on glucose oxidase immobilization. • Chemical analysis showed that after modification of nanofibers by air plasma, the carboxyl group increased. • After air plasma treatment, reusability and storage stability of glucose oxidase immobilized on nanofibers improved. - Abstract: Polymeric nanofiber prepares a suitable situation for enzyme immobilization for variety of applications. In this research, we have fabricated polyvinyl alcohol (PVA)/malonic acid nanofibers using electrospinning. After fabrication of nanofibers, the effect of air, nitrogen, CO_2, and argon DBD (dielectric barrier discharge) plasmas on PVA/malonic acid nanofibers were analysed. Among them, air plasma had the most significant effect on glucose oxidase (GOx) immobilization. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrum analysis and X-ray photoelectron spectroscopy (XPS) results revealed that in case of air plasma modified nanofibers, the carboxyl groups on the surface are increased. The scanning electron microscopy (SEM) images showed that, after GOx immobilization, the modified nanofibers with plasma has retained its nanofiber structure. Finally, we analysed reusability and storage stability of GOx immobilized on plasma modified and unmodified nanofibers. The results were more satisfactory for modified nanofibers with respect to unmodified ones.

Surface modification of polyvinyl alcohol/malonic acid nanofibers by gaseous dielectric barrier discharge plasma for glucose oxidase immobilization

Energy Technology Data Exchange (ETDEWEB)

Afshari, Esmail, E-mail: e.afshari@mail.sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, Evin, 1983963113 Tehran (Iran, Islamic Republic of); Mazinani, Saeedeh [Amirkabir Nanotechnology Research Institute (ANTRI), Amirkabir University of Technology, 15875-4413, Tehran (Iran, Islamic Republic of); Ranaei-Siadat, Seyed-Omid [Protein Research Center, Shahid Beheshti University, Evin, 1983963113 Tehran (Iran, Islamic Republic of); Ghomi, Hamid [Laser and Plasma Research Institute, Shahid Beheshti University, Evin, 1983963113 Tehran (Iran, Islamic Republic of)

2016-11-01

Highlights: • We fabricated polyvinyl alcohol/malonic acid nanofibers using electrospinning. • The surface nanofibers were modified by gaseous (air, nitrogen, CO{sub 2} and argon) dielectric barrier discharge. • Among them, air plasma had the most significant effect on glucose oxidase immobilization. • Chemical analysis showed that after modification of nanofibers by air plasma, the carboxyl group increased. • After air plasma treatment, reusability and storage stability of glucose oxidase immobilized on nanofibers improved. - Abstract: Polymeric nanofiber prepares a suitable situation for enzyme immobilization for variety of applications. In this research, we have fabricated polyvinyl alcohol (PVA)/malonic acid nanofibers using electrospinning. After fabrication of nanofibers, the effect of air, nitrogen, CO{sub 2}, and argon DBD (dielectric barrier discharge) plasmas on PVA/malonic acid nanofibers were analysed. Among them, air plasma had the most significant effect on glucose oxidase (GOx) immobilization. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrum analysis and X-ray photoelectron spectroscopy (XPS) results revealed that in case of air plasma modified nanofibers, the carboxyl groups on the surface are increased. The scanning electron microscopy (SEM) images showed that, after GOx immobilization, the modified nanofibers with plasma has retained its nanofiber structure. Finally, we analysed reusability and storage stability of GOx immobilized on plasma modified and unmodified nanofibers. The results were more satisfactory for modified nanofibers with respect to unmodified ones.

Contrasting characteristics of sub-microsecond pulsed atmospheric air and atmospheric pressure helium-oxygen glow discharges

International Nuclear Information System (INIS)

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

2010-01-01

Glow discharges in air are often considered to be the ultimate low-temperature atmospheric pressure plasmas for numerous chamber-free applications. This is due to the ubiquitous presence of air and the perceived abundance of reactive oxygen and nitrogen species in air plasmas. In this paper, sub-microsecond pulsed atmospheric air plasmas are shown to produce a low concentration of excited oxygen atoms but an abundance of excited nitrogen species, UV photons and ozone molecules. This contrasts sharply with the efficient production of excited oxygen atoms in comparable helium-oxygen discharges. Relevant reaction chemistry analysed with a global model suggests that collisional excitation of O 2 by helium metastables is significantly more efficient than electron dissociative excitation of O 2 , electron excitation of O and ion-ion recombination. These results suggest different practical uses of the two oxygen-containing atmospheric discharges, with air plasmas being well suited for nitrogen and UV based chemistry and He-O 2 plasmas for excited atomic oxygen based chemistry. (fast track communication)

Contribution of a portable air plasma torch to rapid blood coagulation as a method of preventing bleeding

International Nuclear Information System (INIS)

Kuo, S P; Chen, C Y; Fan, H W; Tarasenko, O; Scott, A; Lahiani, M; Alusta, P; Chang, J; Popovic, S; Drake, J D; Nikolic, M

2009-01-01

The effectiveness and mechanism of a low temperature air plasma torch in clotting blood are explored. Both blood droplets and smeared blood samples were used in the tests. The treated droplet samples reveal how blood clotting depends on the distance at which the torch operated, and for how long the droplets have been exposed to the torch. Microscopy and cell count of smeared blood samples shed light on dependencies of erythrocyte and platelet counts on torch distance and exposure time. With an increase of torch distance, the platelet count of treated blood samples increases but is less than that of the control. The flux of reactive atomic oxygen (RAO) and the degree of blood clotting decreased. With an increase of exposure time, platelet count of treated samples decreased, while the degree of clot increased. The correlation among these dependencies and published data support a blood clotting mechanism that RAO as well as other likely reactive oxygen species generated by the plasma torch activate erythrocyte-platelets interactions and induces blood coagulation.

Effect of sample digestion, air filter contamination, and post-adsorption on the analysis of trace elements in air particulate matter

International Nuclear Information System (INIS)

Yang, Xiao Jin; Wan, Pingyu; Foley, Roy

2012-01-01

Inductively coupled plasma atomic emission spectrometry and inductively coupled plasma MS are the major analytical tools for trace elements in environmental matrices, however, the underestimate of certain trace elements in analysis of air particulate matter by these two techniques has long been observed. This has been attributed to incomplete sample digestion. Here, we demonstrate that the combined effects of sample digestion, air filter impurities, and post-adsorption of the analytes contribute to the interference of the analysis. Particular attention should be paid to post-adsorption of analytes onto air filters after acid digestion. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Effect of sample digestion, air filter contamination, and post-adsorption on the analysis of trace elements in air particulate matter

Energy Technology Data Exchange (ETDEWEB)

Yang, Xiao Jin [Department of Environment and Climate Change, Environmental Forensic and Analytical Science Section, New South Wales (Australia); Department of Applied Chemistry, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing (China); Wan, Pingyu [Department of Applied Chemistry, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing (China); Foley, Roy [Department of Environment and Climate Change, Environmental Forensic and Analytical Science Section, New South Wales (Australia)

2012-11-15

Inductively coupled plasma atomic emission spectrometry and inductively coupled plasma MS are the major analytical tools for trace elements in environmental matrices, however, the underestimate of certain trace elements in analysis of air particulate matter by these two techniques has long been observed. This has been attributed to incomplete sample digestion. Here, we demonstrate that the combined effects of sample digestion, air filter impurities, and post-adsorption of the analytes contribute to the interference of the analysis. Particular attention should be paid to post-adsorption of analytes onto air filters after acid digestion. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Sterilization of microbes by using various plasma jets

Energy Technology Data Exchange (ETDEWEB)

Uhm, Han S.; Choi, Eun H.; Cho, Guang S. [Kwangwoon University, Seoul (Korea, Republic of); Hong, Yong C. [National Fusion Research Institute, Daejeon (Korea, Republic of)

2012-03-15

Sterilization of various microbes was carried out by using several plasma jets. Argon plasma jets penetrate deep into ambient air and create a path for oxygen radicals to sterilize microbes including spores. A sterilization experiment with bacterial endospores indicates that an argon-oxygen plasma jet very effectively kills endospores of Bacillus atrophaeus (ATCC 9372), thereby demonstrating its capability to clean surfaces and its usefulness for reinstating contaminated equipment as free from toxic biological agents. The key element of the sterilization is oxygen radicals. The penciltype configuration produces a long, cold plasma jet capable of reaching 3.5 cm and having various excited plasma species shown through the optical emission spectrum. Operation of an air plasma jet at 2 W in a pencil-type electrode provides an excellent opportunity for sterilization of microbes. An electron microscope was used to observe the effects of the plasma on bacterial cell morphology. Transmission electron micrographs showed morphological changes in E. coli cells treated with an atmospheric plasma at 75 W for 2 min. The treated cells had severe cytoplasmic deformations and leakage of bacterial chromosome. The chromosomal DNA was either attached to the bacterial cells or released freely into the surrounding medium. The results clearly explain the loss of viability of bacterial cells after plasma treatment.

Atmospheric-Pressure Plasma Interaction with Soft Materials as Fundamental Processes in Plasma Medicine.

Science.gov (United States)

Takenaka, Kosuke; Miyazaki, Atsushi; Uchida, Giichiro; Setsuhara, Yuichi

2015-03-01

Molecular-structure variation of organic materials irradiated with atmospheric pressure He plasma jet have been investigated. Optical emission spectrum in the atmospheric-pressure He plasma jet has been measured. The spectrum shows considerable emissions of He lines, and the emission of O and N radicals attributed to air. Variation in molecular structure of Polyethylene terephthalate (PET) film surface irradiated with the atmospheric-pressure He plasma jet has been observed via X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). These results via XPS and FT-IR indicate that the PET surface irradiated with the atmospheric-pressure He plasma jet was oxidized by chemical and/or physical effect due to irradiation of active species.

Monolithic PDMS Laminates for Dielectric Elastomer Transducers through Open-Air PlasmATreatment

DEFF Research Database (Denmark)

Hassouneh, Suzan Sager; Oubæk, Jakob; Daugaard, Anders Egede

2016-01-01

The present study investigates the use of an open-air plasma-treatment system for the surface modification of polydimethylsiloxane (PDMS), in order to improve layer-to-layer adhesion. The procedure presented herein is more cost efficient compared to conventional vacuum-based plasma-treatment, and......The present study investigates the use of an open-air plasma-treatment system for the surface modification of polydimethylsiloxane (PDMS), in order to improve layer-to-layer adhesion. The procedure presented herein is more cost efficient compared to conventional vacuum-based plasma...

Investigation of shock compressed plasma parameters by interaction with magnetic field

International Nuclear Information System (INIS)

Dudin, S. V.; Fortov, V. E.; Gryaznov, V. K.; Mintsev, V. B.; Shilkin, N. S.; Ushnurtsev, A. E.

1998-01-01

The Hall effect parameters in shock compressed air, helium and xenon have been estimated and results of experiments with air and helium plasma are presented. Explosively driven shock tubes were used for the generation of strong shock waves. To obtain magnetic field a solenoid was winded over the shock tube. Calculations of dense shock compressed plasma parameters were carried out to plan the experiments. In the experiments with the magnetic field of ∼5 T it was found, that air plasma slug was significantly heated by the whirlwind electrical field. The reflected shock waves technique was used in the experiments with helium. Results on measurements of electrical conductivity and electron concentration of helium are presented

Seed disinfection effect of atmospheric pressure plasma and low pressure plasma on Rhizoctonia solani.

Science.gov (United States)

Nishioka, Terumi; Takai, Yuichiro; Kawaradani, Mitsuo; Okada, Kiyotsugu; Tanimoto, Hideo; Misawa, Tatsuya; Kusakari, Shinichi

2014-01-01

Gas plasma generated and applied under two different systems, atmospheric pressure plasma and low pressure plasma, was used to investigate the inactivation efficacy on the seedborne pathogenic fungus, Rhizoctonia solani, which had been artificially introduced to brassicaceous seeds. Treatment with atmospheric plasma for 10 min markedly reduced the R. solani survival rate from 100% to 3% but delayed seed germination. The low pressure plasma treatment reduced the fungal survival rate from 83% to 1.7% after 10 min and the inactivation effect was dependent on the treatment time. The seed germination rate after treatment with the low pressure plasma was not significantly different from that of untreated seeds. The air temperature around the seeds in the low pressure system was lower than that of the atmospheric system. These results suggested that gas plasma treatment under low pressure could be effective in disinfecting the seeds without damaging them.

Simulation of laser interaction with ablative plasma and hydrodynamic behavior of laser supported plasma

Energy Technology Data Exchange (ETDEWEB)

Tong Huifeng; Yuan Hong [Institute of Fluid Physics, Chinese Academy of Engineering Physics, P.O. Box 919-101, Mianyang, Sichuan 621900 (China); Tang Zhiping [CAS Key Laboratory for Mechanical Behavior and Design of Materials, Department of Mechanics and Mechanical Engineering, University of Science and Technology of China, Hefei 230026 (China)

2013-01-28

When an intense laser beam irradiates on a solid target, ambient air ionizes and becomes plasma, while part of the target rises in temperature, melts, vaporizes, ionizes, and yet becomes plasma. A general Godunov finite difference scheme WENO (Weighted Essentially Non-Oscillatory Scheme) with fifth-order accuracy is used to simulate 2-dimensional axis symmetrical laser-supported plasma flow field in the process of laser ablation. The model of the calculation of ionization degree of plasma and the interaction between laser beam and plasma are considered in the simulation. The numerical simulations obtain the profiles of temperature, density, and velocity at different times which show the evolvement of the ablative plasma. The simulated results show that the laser energy is strongly absorbed by plasma on target surface and that the velocity of laser supported detonation (LSD) wave is half of the ideal LSD value derived from Chapman-Jouguet detonation theory.

Prooxidant Effects of Verbascoside, a Bioactive Compound from Olive Oil Mill Wastewater, on In Vitro Developmental Potential of Ovine Prepubertal Oocytes and Bioenergetic/Oxidative Stress Parameters of Fresh and Vitrified Oocytes

Science.gov (United States)

Dell'Aquila, M. E.; Bogliolo, L.; Russo, R.; Martino, N. A.; Filioli Uranio, M.; Ariu, F.; Amati, F.; Sardanelli, A. M.; Linsalata, V.; Ferruzzi, M. G.; Cardinali, A.; Minervini, F.

2014-01-01

Verbascoside (VB) is a bioactive polyphenol from olive oil mill wastewater with known antioxidant activity. Oxidative stress is an emerging problem in assisted reproductive technology (ART). Juvenile ART is a promising topic because, in farm animals, it reduces the generation gap and, in human reproductive medicine, it helps to overcome premature ovarian failure. The aim of this study was to test the effects of VB on the developmental competence of ovine prepubertal oocytes and the bioenergetic/oxidative stress status of fresh and vitrified oocytes. In fresh oocytes, VB exerted prooxidant short-term effects, that is, catalase activity increase and uncoupled increases of mitochondria and reactive oxygen species (ROS) fluorescence signals, and long-term effects, that is, reduced blastocyst formation rate. In vitrified oocytes, VB increased ROS levels. Prooxidant VB effects in ovine prepubertal oocytes could be related to higher VB accumulation, which was found as almost one thousand times higher than that reported in other cell systems in previous studies. Also, long exposure times of oocytes to VB, throughout the duration of in vitro maturation culture, may have contributed to significant increase of oocyte oxidation. Further studies are needed to identify lower concentrations and/or shorter exposure times to figure out VB antioxidant effects in juvenile ARTs. PMID:24719893

Prooxidant Effects of Verbascoside, a Bioactive Compound from Olive Oil Mill Wastewater, on In Vitro Developmental Potential of Ovine Prepubertal Oocytes and Bioenergetic/Oxidative Stress Parameters of Fresh and Vitrified Oocytes

Directory of Open Access Journals (Sweden)

M. E. Dell'Aquila

2014-01-01

Full Text Available Verbascoside (VB is a bioactive polyphenol from olive oil mill wastewater with known antioxidant activity. Oxidative stress is an emerging problem in assisted reproductive technology (ART. Juvenile ART is a promising topic because, in farm animals, it reduces the generation gap and, in human reproductive medicine, it helps to overcome premature ovarian failure. The aim of this study was to test the effects of VB on the developmental competence of ovine prepubertal oocytes and the bioenergetic/oxidative stress status of fresh and vitrified oocytes. In fresh oocytes, VB exerted prooxidant short-term effects, that is, catalase activity increase and uncoupled increases of mitochondria and reactive oxygen species (ROS fluorescence signals, and long-term effects, that is, reduced blastocyst formation rate. In vitrified oocytes, VB increased ROS levels. Prooxidant VB effects in ovine prepubertal oocytes could be related to higher VB accumulation, which was found as almost one thousand times higher than that reported in other cell systems in previous studies. Also, long exposure times of oocytes to VB, throughout the duration of in vitro maturation culture, may have contributed to significant increase of oocyte oxidation. Further studies are needed to identify lower concentrations and/or shorter exposure times to figure out VB antioxidant effects in juvenile ARTs.

Destruction of Bacillus subtilis cells using an atmospheric-pressure dielectric capillary electrode discharge plasma

International Nuclear Information System (INIS)

Panikov, N.S.; Paduraru, S.; Crowe, R.; Ricatto, P.J.; Christodoulatos, C.; Becker, K.

2002-01-01

The results of experiments aimed at the investigation of the destruction of spore-forming bacteria, which are believed to be among the most resistant microorganisms, using a novel atmospheric-pressure dielectric capillary electrode discharge plasma are reported. Various well-characterized cultures of Bacillus subtilis were prepared, subjected to atmospheric-pressure plasma jets emanating from a plasma shower reactor operated either in He or in air (N 2 /O 2 mixture) at various power levels and exposure times, and analyzed after plasma treatment. Reductions in colony-forming units ranged from 10 4 (He plasma) to 10 8 (air plasma) for plasma exposure times of less than 10 minutes. (author)

Development of a unit cell model for interim performance assessment of vitrified low level waste disposal

International Nuclear Information System (INIS)

Kline, N.W.

1995-09-01

The unit cell modeling approach has been developed and used in analysis of some design options for a vitrified low level waste disposal facility. The unit cell modeling approach is likely to be useful in interim performance assessment for the facility. The present unit cell model will probably need to be refitted in terms of some model parameters for the latter purpose. Two present disposal facility concepts differ in the length of a capillary barrier proposed to limit effective recharge through the top of the facility. Results of the study summarized herein suggest design of a capillary barrier which can reduce a recharge rate of 0.1 cm/yr by one or two orders of magnitude seems feasible for both concepts. A benchmark comparison of the unit cell model against a full facility model shows comparable predictive accuracy in less than one percent of the computer time. Results suggest that model parameters include capillary barrier performance, inter-canister spacing, rate of moisture withdrawal due to glass corrosion, contaminant inventory, and the well interceptor factor. It is also important that variations of waste form hydraulic parameters suggest that transport through the waste form is dominated by diffusion

Failure analysis of thermally cycled columnar thermal barrier coatings produced by high-velocity-air fuel and axial-suspension-plasma spraying: A design perspective

Czech Academy of Sciences Publication Activity Database

Ganvir, A.; Vaidhyanathan, V.; Markocsan, N.; Gupta, M.; Pala, Zdeněk; Lukáč, František

2018-01-01

Roč. 44, č. 3 (2018), s. 3161-3172 ISSN 0272-8842 Institutional support: RVO:61389021 Keywords : Columnar Thermal Barrier Coatings * Axial Suspension Plasma spraying * Thermal Cyclic Fatigue * High Velocity Air Fuel Spraying Subject RIV: JK - Corrosion ; Surface Treatment of Materials OBOR OECD: Coating and films Impact factor: 2.986, year: 2016 https://www.sciencedirect.com/science/article/pii/S0272884217325403

Preparation and characterization of molybdenum disilicide coating on molybdenum substrate by air plasma spraying

International Nuclear Information System (INIS)

Wang, Yi; Wang, Dezhi; Yan, Jianhui; Sun, Aokui

2013-01-01

MoSi 2 oxidation protective coatings on molybdenum substrate were prepared by air plasma spraying technique (APS). Microstructure, phase composition, porosity, microhardness and bonding strength of the coatings were investigated and determined. Oxidation behavior of the coating at high temperature was also examined. Results show that composition of the coatings is constituted with MoSi 2 and Mo 5 Si 3 , the surface morphology is described as flattened lamellar features, insufficiently flattened protuberance with some degree of surface roughness, a certain quantity of spherical particles, microcracks and pores. Testing results reveal that microhardness and bonding strength of the coatings increase, and porosity decreases with increasing power or decreasing Ar gas flow rate. Moreover, with decreasing the porosity, the microhardness of the coatings increases. The bonding strength of the coatings also increases with increasing spray distance. The MoSi 2 coated Mo substrate exhibited a good oxidation resistance at 1200 °C.

Bacteria killing effect of pulsed plasmas in oxygen+air at atmospheric pressure

International Nuclear Information System (INIS)

Akan, T.

2005-01-01

Bacteria Killing Method. The high voltage pulsed plasma is a non-equilibrium plasma and generates UV photons, ozone and active oxygen. The aim of this paper is to present a simple device to generate plasma able to kill efficiently bacteria. One of the probes charged with bacteria, was kept as a control probes (not exposed to the pulsed plasma), the rest of the probes were exposed to the pulsed plasma and afterwards compared with above mentioned control probe (reference sample). During treatment the bacteria were exposed to the active atoms, molecules, charged particles and photons generated by the pulsed plasma. The temperature of the support of samples with bacteria exposed to plasma increased during the treatment with only 1-2 degrees. Full killing time of Staphylococcus species as low as 3 minutes have been obtained quite easily

Plasma Surface interaction in Controlled fusion devices

International Nuclear Information System (INIS)

1990-05-01

The subjects presented in the 9th conference on plasma surface interaction in controlled fusion devices were: the modifications of power scrape-off-length and power deposition during various configurations in Tore Supra plasmas; the effects observed in ergodic divertor experiments in Tore-Supra; the diffuse connexion induced by the ergodic divertor and the topology of the heat load patterns on the plasma facing components in Tore-Supra; the study of the influence of air exposure on graphite implanted by low energy high density deuterium plasma

Reevaluation of Vitrified High-Level Waste Form Criteria for Potential Cost Savings at the Defense Waste Processing Facility - 13598

Energy Technology Data Exchange (ETDEWEB)

Ray, J.W. [Savannah River Remediation (United States); Marra, S.L.; Herman, C.C. [Savannah River National Laboratory, Savannah River Site, Aiken, SC 29808 (United States)

2013-07-01

At the Savannah River Site (SRS) the Defense Waste Processing Facility (DWPF) has been immobilizing SRS's radioactive high level waste (HLW) sludge into a durable borosilicate glass since 1996. Currently the DWPF has poured over 3,500 canisters, all of which are compliant with the U. S. Department of Energy's (DOE) Waste Acceptance Product Specifications for Vitrified High-Level Waste Forms (WAPS) and therefore ready to be shipped to a federal geologic repository for permanent disposal. Due to DOE petitioning to withdraw the Yucca Mountain License Application (LA) from the Nuclear Regulatory Commission (NRC) in 2010 and thus no clear disposal path for SRS canistered waste forms, there are opportunities for cost savings with future canister production at DWPF and other DOE producer sites by reevaluating high-level waste form requirements and compliance strategies and reducing/eliminating those that will not negatively impact the quality of the canistered waste form. (authors)

Generation of live offspring from vitrified embryos with synthetic polymers SuperCool X-1000 and SuperCool Z-1000.

Science.gov (United States)

Marco-Jimenez, F; Jimenez-Trigos, E; Lavara, R; Vicente, J S

2014-01-01

Ice growth and recrystallisation are considered important factors in determining vitrification outcomes. Synthetic polymers inhibit ice formation during cooling or warming of the vitrification process. The aim of this study was to assess the effect of adding commercially available synthetic polymers SuperCool X-1000 and SuperCool Z-1000 to vitrification media on in vivo development competence of rabbit embryos. Four hundred and thirty morphologically normal embryos recovered at 72 h of gestation were used. The vitrification media contained 20% dimethyl sulphoxide and 20% ethylene glycol, either alone or in combination with 1% of SuperCool X-1000 and 1% SuperCool. Our results show that embryos can be successfully vitrified using SuperCool X-1000 and SuperCool Z-1000 and when embryos are transferred, live offspring can be successfully produced. In conclusion, our results demonstrated that we succeeded for the first time in obtaining live offspring after vitrification of embryos using SuperCool X-1000 and SuperCool Z-1000 polymers.

CASTOR registered HAW28M - a high heat load cask for transport and storage of vitrified high level waste containers

International Nuclear Information System (INIS)

Vossnacke, A.; Klein, K.; Kuehne, B.

2004-01-01

Within the German return programme for vitrified high level waste (HLW) from reprocessing at COGEMA and BNFL up to now 39 casks loaded with 28 containers each were transported back to Germany and are stored in the Interim Storage Facility Gorleben (TBL-G) for up to 40 years. For transport and storage in all but one case the GNB casks CASTOR registered HAW 20/28 CG have been used. This cask type is designed to accommodate 20 or 28 HLW containers with a total thermal power of 45 kW maximum. In the near future, among the high level waste, which has to be returned to Germany, there will be an increasing number of containers of which the heat capacity and radioactive inventory will exceed the technical limits of the CASTOR registered HAW 20/28 CG. Therefore GNB has started the development of a new cask generation, named CASTOR registered HAW28M, meeting these future requirements. The CASTOR registered HAW28M is especially developed for the transport of vitrified residues from France and Great Britain to Germany. It complies with the international regulations for type B packages according to IAEA (International Atomic Energy Agency). It is thus guaranteed that even in case of any accident the cask body and the lid system remain functional and the safe confinement of the radioactive contents remains intact during transport. The CASTOR registered HAW28M fulfills not only the requirements for transport but also the acceptance criteria of interim storage: radiation shielding, heat dissipation, safe confinement under both normal and hypothetical accident conditions. Storage buildings such as the TBL-G simply support the safety functions of the cask. The challenge for the development results from higher requirements of the technical specification, particularly related to fuel which is reprocessed. As a consequence of the reprocessing of fuel with increased enrichment and burn up, higher heat capacity and sophisticated shielding measures have to be considered. For the CASTOR

Oxidation mechanisms of CF2Br2 and CH2Br2 induced by air nonthermal plasma.

Science.gov (United States)

Schiorlin, Milko; Marotta, Ester; Dal Molin, Marta; Paradisi, Cristina

2013-01-02

Oxidation mechanisms in air nonthermal plasma (NTP) at room temperature and atmospheric pressure were investigated in a corona reactor energized by +dc, -dc, or +pulsed high voltage.. The two bromomethanes CF(2)Br(2) and CH(2)Br(2) were chosen as model organic pollutants because of their very different reactivities with OH radicals. Thus, they served as useful mechanistic probes: they respond differently to the presence of humidity in the air and give different products. By FT-IR analysis of the postdischarge gas the following products were detected and quantified: CO(2) and CO in the case of CH(2)Br(2), CO(2) and F(2)C ═ O in the case of CF(2)Br(2). F(2)C ═ O is a long-lived oxidation intermediate due to its low reactivity with atmospheric radicals. It is however removed from the NTP processed gas by passage through a water scrubber resulting in hydrolysis to CO(2) and HF. Other noncarbon containing products of the discharge were also monitored by FT-IR analysis, including HNO(3) and N(2)O. Ozone, an important product of air NTP, was never detected in experiments with CF(2)Br(2) and CH(2)Br(2) because of the highly efficient ozone depleting cycles catalyzed by BrOx species formed from the bromomethanes. It is concluded that, regardless of the type of corona applied, CF(2)Br(2) reacts in air NTP via a common intermediate, the CF(2)Br radical. The possible reactions leading to this radical are discussed, including, for -dc activation, charge exchange with O(2)(-), a species detected by APCI mass spectrometry.

Fiber-optic laser-induced breakdown spectroscopy of zirconium metal in air: Special features of the plasma produced by a long-pulse laser

Science.gov (United States)

Matsumoto, Ayumu; Ohba, Hironori; Toshimitsu, Masaaki; Akaoka, Katsuaki; Ruas, Alexandre; Sakka, Tetsuo; Wakaida, Ikuo

2018-04-01

The decommissioning of the Tokyo Electric Power Company (TEPCO) Fukushima Daiichi Nuclear Power Plant is an essential issue in nuclear R&D. Fiber-optic laser-induced breakdown spectroscopy (Fiber-optic LIBS) could be used for in-situ elemental analysis of the inside of the damaged reactors. To improve the performances under difficult conditions, using a long-pulse laser can be an efficient alternative. In this work, the emission spectra of zirconium metal in air obtained for a normal-pulse laser (6 ns) and a long-pulse laser (100 ns) (wavelength: 1064 nm, pulse energy: 12.5 mJ, spot diameter: 0.35 mm) are compared to investigate the fundamental aspects of fiber-optic LIBS with the long-pulse laser. The spectral features are considerably different: when the long-pulse laser is used, the atomic and molecular emission is remarkably enhanced. The enhancement of the atomic emission at the near infrared (NIR) region would lead to the observation of emission lines with minimum overlapping. To understand the differences in the spectra induced respectively from the normal-pulse laser and the long-pulse laser, photodiode signals, time-resolved spectra, plasma parameters, emission from the ambient air, and emission regions are investigated, showing the particular characteristics of the plasma produced by the long-pulse laser.

Friction and wear properties of Ti6Al4V/WC-Co in cold atmospheric plasma jet

International Nuclear Information System (INIS)

Xu Wenji; Liu Xin; Song Jinlong; Wu Libo; Sun Jing

2012-01-01

Highlights: ► Cold plasma jet can effectively reduce the friction coefficients of Ti6Al4V/WC-Co friction pairs. ► Cold plasma jet can easily form nitrides on the surface of Ti6Al4V and on new surfaces generated by tool wear. ► The nitrides can reduce the friction coefficients and protect the friction surface. - Abstract: The friction and wear properties of Ti6Al4V/WC-Co friction pair were studied using an autonomous atmospheric pressure bare electrode cold plasma jet generating device and block-on-ring friction/wear tester, respectively. The study was conducted under air, air jet, nitrogen jet, air cold plasma jet, and nitrogen cold plasma jet atmospheres. Both nitrogen cold and air cold plasma jets effectively reduced the friction coefficients of the friction pairs and decreased friction temperature. The friction coefficient in the nitrogen cold plasma jet decreased to almost 60% compared with that in the air. The scanning electron microscope, energy-dispersive X-ray spectroscope, and X-ray diffraction analyses illustrated that adhesive wear was relieved and the friction surfaces of Ti6Al4V were smoother, both in the nitrogen cold and air cold plasma jets. The roughness value R a of the Ti6Al4V friction surfaces can reach 1.107 μm. A large number of nitrogen particles in the ionic and excited states contained by cold plasma jets reacts easily on the friction surface to produce a large amount of nitrides, which can excellently reduce the wear of Ti6Al4V/WC-Co friction pairs in real-time.

Plasma-Gasification-Melting System (PGM) for Treatment of Low and Intermediate Level Radioactive Waste (LILRW) Generated by Nuclear Power Plants (NPP's)

International Nuclear Information System (INIS)

Pegaz, D.

2004-01-01

Solid LILRW generated by NPP's is treated by various methods of Volume Reduction and Stabilization / Immobilization before disposal at suitable Storage Sites for Radioactive Waste. PGM Technology thermally treats such solid LILRW achieving maximum volume reduction and efficient stabilization of radionuclides of the waste in a Vitrified (glassy) solid residue, slag. Since such LILRW is made of a large variety of different materials, organic and inorganic, the PGM Process gasifies and pyrolizes the organics while the inorganics are melted and vitrified

Atomic Oxygen Energy in Low Frequency Hyperthermal Plasma Ashers

Science.gov (United States)

Banks, Bruce A.; Miller, Sharon K R.; Kneubel, Christian A.

2014-01-01

Experimental and analytical analysis of the atomic oxygen erosion of pyrolytic graphite as well as Monte Carlo computational modeling of the erosion of Kapton H (DuPont, Wilmington, DE) polyimide was performed to determine the hyperthermal energy of low frequency (30 to 35 kHz) plasma ashers operating on air. It was concluded that hyperthermal energies in the range of 0.3 to 0.9 eV are produced in the low frequency air plasmas which results in texturing similar to that in low Earth orbit (LEO). Monte Carlo computational modeling also indicated that such low energy directed ions are fully capable of producing the experimentally observed textured surfaces in low frequency plasmas.

Sustained diffusive alternating current gliding arc discharge in atmospheric pressure air

DEFF Research Database (Denmark)

Zhu, Jiajian; Gao, Jinlong; Li, Zhongshan

2014-01-01

Rapid transition from glow discharge to thermal arc has been a common problem in generating stable high-power non-thermal plasmas especially at ambient conditions. A sustained diffusive gliding arc discharge was generated in a large volume in atmospheric pressure air, driven by an alternating...... current (AC) power source. The plasma column extended beyond the water-cooled stainless steel electrodes and was stabilized by matching the flow speed of the turbulent air jet with the rated output power. Comprehensive investigations were performed using high-speed movies measured over the plasma column...

Surface plasmon resonance investigation of optical detection in plasma-modified phospholipid layers

International Nuclear Information System (INIS)

Park, Byoungchoo; Cho, Chanyoun; Choi, Kyoungho; Jeon, Honggoo

2012-01-01

We herein report on a study of surface plasmon resonance (SPR) in thin gold (Au) films coated with thin layers of phospholipid material, which had been exposed to an atmospheric pressure (AP) plasma containing both pure Ar and Ar mixed with O 2 (Ar/O 2 , 0.8%). The phospholipid material that we used for the SPR experiments was lecithin, and the AP plasma system was applied in air by means of a radio-frequency (RF) plasma generator. A thin (∼60 nm) film of Au and a thin (∼15 nm) layer of lecithin were deposited and attached to the face of a prism, and surface plasmon modes were excited along the interfaces of the prism-Au-lecithin-air system by means of prism coupling using a He-Ne Laser (632.8 nm). The experimental SPR reflectance curves of the Au-lecithin-air modes were found to be shifted towards those of the Au-air mode with increasing applications of AP RF plasma treatment. From the shifts in the SPR curves, we found that the estimated thickness of the lecithin layer treated with a pure Ar plasma showed a linear decrease with etching rate of about 3 nm per treatment while the thickness of the lecithin layer treated with a mixed Ar/O 2 plasma showed a tendency to saturate following a large initial decrease (ca. 14 nm). All these results demonstrate that the use of SPR sensing could facilitate the detection of extremely small variations in plasma-treated films of biomaterials.

Preparation and characterization of molybdenum disilicide coating on molybdenum substrate by air plasma spraying

Energy Technology Data Exchange (ETDEWEB)

Wang, Yi [Key Laboratory of Ministry of Education for Non-ferrous Materials Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Hunan Province for Metallurgy and Material Processing of Rare Metals, Central South University, Changsha 410083 (China); School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Wang, Dezhi, E-mail: dzwang68@163.com [Key Laboratory of Ministry of Education for Non-ferrous Materials Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Hunan Province for Metallurgy and Material Processing of Rare Metals, Central South University, Changsha 410083 (China); School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Yan, Jianhui [Advanced Materials Synthesis and Application Technology Laboratory, Hunan University of Science and Technology, Xiangtan 411201 (China); Sun, Aokui [Key Laboratory of Ministry of Education for Non-ferrous Materials Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Hunan Province for Metallurgy and Material Processing of Rare Metals, Central South University, Changsha 410083 (China); School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

2013-11-01

MoSi{sub 2} oxidation protective coatings on molybdenum substrate were prepared by air plasma spraying technique (APS). Microstructure, phase composition, porosity, microhardness and bonding strength of the coatings were investigated and determined. Oxidation behavior of the coating at high temperature was also examined. Results show that composition of the coatings is constituted with MoSi{sub 2} and Mo{sub 5}Si{sub 3}, the surface morphology is described as flattened lamellar features, insufficiently flattened protuberance with some degree of surface roughness, a certain quantity of spherical particles, microcracks and pores. Testing results reveal that microhardness and bonding strength of the coatings increase, and porosity decreases with increasing power or decreasing Ar gas flow rate. Moreover, with decreasing the porosity, the microhardness of the coatings increases. The bonding strength of the coatings also increases with increasing spray distance. The MoSi{sub 2} coated Mo substrate exhibited a good oxidation resistance at 1200 °C.

Production of extended plasma channels in atmospheric air by amplitude-modulated UV radiation of GARPUN-MTW Ti : sapphire—KrF laser. Part 2. Accumulation of plasma electrons and electric discharge control

Science.gov (United States)

Zvorykin, V. D.; Ionin, Andrei A.; Levchenko, A. O.; Mesyats, Gennadii A.; Seleznev, L. V.; Sinitsyn, D. V.; Smetanin, Igor V.; Sunchugasheva, E. S.; Ustinovskii, N. N.; Shutov, A. V.

2013-04-01

The problem of the production of extended (~1 m) plasma channels is studied in atmospheric air by amplitude-modulated laser pulses of UV radiation, which are a superposition of a subpicosecond USP train amplified in a regenerative KrF amplifier with an unstable confocal resonator and a quasi-stationary lasing pulse. The USPs possess a high (0.2-0.3 TW) peak power and efficiently ionise oxygen molecules due to multiphoton ionisation, and the quasi-stationary lasing pulse, which has a relatively long duration (~100 ns), maintains the electron density at a level ne = (3-5) × 1014 cm—3 by suppressing electron attachment to oxygen. Experiments in laser triggering of high-voltage electric discharges suggest that the use of combined pulses results in a significant lowering of the breakdown threshold and enables controlling the discharge trajectory with a higher efficiency in comparison with smooth pulses. It was shown that controlled breakdowns may develop with a delay of tens of microseconds relative to the laser pulse, which is many orders of magnitude greater than the lifetime of free electrons in the laser-induced plasma. We propose a mechanism for this breakdown, which involves speeding-up of the avalanche ionisation of the air by negative molecular oxygen ions with a low electron binding energy (~0.5 eV) and a long lifetime (~1 ms), which are produced upon cessation of the laser pulse.

Study on the effects of physical plasma on in-vitro cultivates cells

International Nuclear Information System (INIS)

Strassenburg, Susanne

2014-03-01

This study focused on the interactions of non thermal atmospheric pressure plasma on in vitro cultured keratinocytes (HaCaT keratinocytes) and melanoma cells (MV3). Three different plasma sources were used: a plasma jet (kINPen 09), a surface DBD (dielectric barrier discharge) and a volume DBD. For analyzing basic effects of plasma on cells, influence of physical plasma on viability, on DNA and on induction of ROS were investigated. Following assays were used: -- Viability: - neutral red uptake assay, cell counting (number of viable cells, cell integrity) - BrdU assay (proliferation) - Annexin V and propidium iodide staining, flow cytometry (induction of apoptosis), -- DNA: - alkaline comet assay (detection of DNA damage) - staining of DNA with propidium iodide, flow cytometry (cell cycle analysis), -- ROS: - H2DCFDA assay, flow cytometry (detection of ROS-positive cells). In addition to the effects which where induced by the plasma sources, the influence of the plasma treatment regime (direct, indirect and direct with medium exchange), the working gas (argon, air) and the surrounding liquids (cell culture medium: RPMI, IMDM; buffer solutions: HBSS, PBS) on the extent of the plasma cell effects were investigated. All plasma sources induced treatment time-dependent effects in HaCaT keratinocytes and melanoma cells (MV3): - loss of viable cells and reduced proliferation - induction of apoptosis after the longest treatment times - DNA damage 1 h after plasma treatment, 24 h after plasma treatment DNA damage was present only after the longest treatment times, evidence for DNA damage repair - due to accumulation of cells in G2/M phase, cell count in G1 phase (24 h) is lower - increase of ROS-positive cells 1 h and 24 h after plasma treatment. It was shown that cells which were cultured in RPMI showed stronger effects (stronger loss of viability and more DNA damage) than cells which were cultured in IMDM. Also plasma-treated buffer solutions (HBSS, PBS) induced DNA

Surface modification of polyethylene by plasma

International Nuclear Information System (INIS)

Colin O, E.

2003-01-01

The products made of polyethylene (PE) go from construction materials, electric insulating until packing material. The films for bags and pack occupy 83.6% of the distribution of the market of PE approximately. The enormous quantity of PE that is generated by its indiscriminate use brings as consequence a deterioration to the atmosphere, due to the long life that they present as waste. This work is a study on the modification of low density polyethylene films. In this type of thin materials, the changes in the surface meet with largely on the conformation of the rest of the material. To induce changes that modify the surface of PE, plasmas were used with reactive atmospheres of air, oxygen and nitrogen. The experimentation that was carries out went to introduce the PE to a cylindrical reactor where it was generated the plasma of air, oxygen and nitrogen to different times of exposure. After having carried out the exposure to the plasma, it was found that in the polyethylene it modifies their morphology, crystallinity, hydrophobicity, composition and electric conductivity. The analytical techniques that were used to characterize later to the polyethylene of being in contact with the plasma were: X-ray diffraction, Scanning Electron Microscopy, Infrared spectroscopy, Electric conductivity, Angle of contact and finally Thermal Gravimetric Analysis. The content of this work it is presented in five chapters: In the chapter 1 there are presented some general concepts of plasma and of the one polymer in study PE. In the chapter 2 it is made a general revision on modification of surfaces, as well as the properties that were modified in polymeric materials that were exposed to plasma in previous works. In the chapter 3 the experimental part and the conditions used are described in the modification of the PE. Also in this chapter a brief description it is made of the used characterization techniques. The results and discussion are presented in the chapter 4. These results

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

Science.gov (United States)

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

2010-01-01

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

Modifications in SnS thin films by plasma treatments

Energy Technology Data Exchange (ETDEWEB)

Martinez, H., E-mail: hm@fis.unam.mx [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62210 Cuernavaca, Morelos (Mexico); Avellaneda, D. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon (Mexico)

2012-02-01

The present study shows the modifications of structural, optical and electrical characteristics that occur in tin sulfide (SnS) thin films treated in air and in nitrogen plasma at different pressure conditions. The films were obtained by the chemical bath deposition method, which results in SnS thin films with an orthorhombic crystalline structure, band gap (E{sub g}) of 1.1-1.2 eV, and electrical conductivities ({sigma}) in the order of 10{sup -6} {Omega}{sup -1}cm{sup -1}. The films treated with air plasma at pressures between 1 and 4 Torr, showed the presence of SnS{sub 2}, Sn{sub 2}S{sub 3}, and SnO{sub 2} phases, within the band gap values ranging from 0.9 to 1.5 eV. On the other hand, the films treated with nitrogen plasma presented the same phases, but showed a significant modification in the electrical conductivity, increasing from 10{sup -6} {Omega}{sup -1}cm{sup -1} (as-deposited) up to 10{sup -2}-10{sup -3} {Omega}{sup -1}cm{sup -1} (plasma treated). This result is a suitable range of conductivity for the improvement of the solar cells with SnS as an absorber material. Also, emission spectroscopy measurements were carried out in both air and nitrogen plasma treatments.

Ball lightning as a spherical plasma configuration of relevance to industrial plasma engineering

International Nuclear Information System (INIS)

Roth, J.R.

1992-01-01

One of the most interesting spherical plasma configurations found in nature is ball lightning, which has been extensively observed in atmospheric air, usually in association with thunderstorms. If the physical processes responsible for ball lightning were understood, this knowledge would have very interesting implications not only for fusion research, but also for industrial plasma engineering. The ability to create a steady-state atmospheric glow discharge would allow many surface modification and other plasma processing applications to be carried out under atmospheric conditions, rather than in expensive vacuum systems which enforce batch processing operations. The existence of ball lightning offers encouragement for the belief that a steady-state atmospheric glow discharge may be possible. Much progress has been made in theoretical attempts to understand ball lightning, perhaps the most comprehensive of which is the Koloc model. This and related models have not satisfactorily dealt with the long plasma lifetimes in the face of electron scattering at atmospheric density. This leads to an unsatisfactory aspect of the Koloc model, the requirement of a shell of relativistic electrons with very low Coulomb scattering cross sections. This last major conceptual roadblock in understanding ball lightning may have been removed by the recent suggestion of Witalis who pointed out that atmospheric gases, or their products, can exhibit the Ramsauer effect, extremely low electron scattering cross sections at low electron kinetic temperatures, on the order of one eV. This recent progress in ball lightning models has stimulated research aimed at producing a steady state glow discharge in air at atmospheric pressure. Such a glow discharge in argon with a few ppm of acetone has been reported by Kanda, et al. At the UTK Plasma Science Laboratory, the authors have generated at 2.8 liter plasma in a steady-state atmospheric pressure glow discharge in helium and other gases

A comparative study on the transdermal penetration effect of gaseous and aqueous plasma reactive species

Science.gov (United States)

Liu, Xin; Gan, Lu; Ma, Mingyu; Zhang, Song; Liu, Jingjing; Chen, Hongxiang; Liu, Dawei; Lu, Xinpei

2018-02-01

To improve the depth of plasma active species in the skin, it is very important to develop skin disease treatment using plasma. In this article, an air plasma source was used to work directly with the skin of a mouse. A tortuous pathway, hair follicles, electroporation and a microneedle do not aid the transdermal delivery of gaseous plasma active species, therefore these gaseous plasma active species cannot penetrate mouse skin with a thickness of ~0.75 mm. The plasma activated water (PAW) produced by the air plasma source was used to study the transdermal penetration of the aqueous plasma activated species. This aqueous plasma activated species can penetrate the skin through hair follicles, intercellular and transcellular routes. The pH of the PAW did not affect the penetration efficiency of the aqueous plasma active species.

NF-PRO research on a repository for vitrified waste and spent fuel

International Nuclear Information System (INIS)

Sneyers, A.

2006-01-01

NF-PRO is a four-year (2004-2007) Integrated Project supported by funding under the Sixth Research (EURATOM) Programme of the European Commission. NF-PRO is coordinated by SCK C EN and investigates key processes in the near-field of geological repositories for the disposal of high-level vitrified waste and spent nuclear fuel. The near-field of a geological repository consists of the area surrounding the waste packages and is composed of several engineered barriers that enclose and confine the disposed waste. These barriers include the waste form, the waste canisters, backfills, seals, plugs and the part of the host rock that has been modified by the excavation of the repository. In all repository designs under investigation within EU Member States, the near-field plays an important role in ensuring the overall safety of disposal: its principal function is to retain radionuclides over extended periods of time and to minimise their release from the waste to the host rock. The main objective of NF-PRO is to integrate European research on the near field with the aim of enhancing common understanding of the long-term changes taking place in a deep repository. NF-PRO assesses how these changes affect the containment of the disposed radioactive waste. Knowledge generated by the project can be applied in waste management programmes to optimise repository designs and to make barriers functional and resource-efficient. The integration of results from detailed process studies in assessments on the overall near-field system performance is a key objective of NF-PRO. The level of integration envisaged by NF-PRO has not yet been achieved in earlier research projects supported by the European Commission. Accordingly, NF PRO represents a major step forward in the establishing of the scientific and technical basis for geological disposal and the safe management of radioactive wastes

Effects of High Hydrostatic Pressure on Expression Profiles of In Vitro Produced Vitrified Bovine Blastocysts

Science.gov (United States)

Jiang, Zongliang; Harrington, Patrick; Zhang, Ming; Marjani, Sadie L.; Park, Joonghoon; Kuo, Lynn; Pribenszky, Csaba; Tian, Xiuchun (Cindy)

2016-01-01

High hydrostatic pressure (HHP) has been used to pre-condition embryos before essential, yet potentially detrimental procedures such as cryopreservation. However, the mechanisms for HHP are poorly understood. We treated bovine blastocysts with three different HHP (40, 60 and 80 MPa) in combination with three recovery periods (0, 1 h, 2 h post HHP). Re-expansion rates were significantly higher at 40 and 60 but lower at 80 MPa after vitrification-warming in the treated groups than controls. Microarray analysis revealed 399 differentially expressed transcripts, representing 254 unique genes, among different groups. Gene ontology analysis indicated that HHP at 40 and 60 MPa promoted embryo competence through down-regulation of genes in cell death and apoptosis, and up-regulation of genes in RNA processing, cellular growth and proliferation. In contrast, 80 MPa up-regulated genes in apoptosis, and down-regulated protein folding and cell cycle-related genes. Moreover, gene expression was also influenced by the length of the recovery time after HHP. The significantly over-represented categories were apoptosis and cell death in the 1 h group, and protein folding, response to unfolded protein and cell cycle in the 2 h group compared to 0 h. Taken together, HHP promotes competence of vitrified bovine blastocysts through modest transcriptional changes. PMID:26883277

Thomson, Raman and Rayleigh scattering on atmospheric plasma jets

NARCIS (Netherlands)

Gessel, van A.F.H.

2010-01-01

Non-equilibrium atmospheric pressure plasma jets are the subject of growing interest, due to their applicability in many fields, including material processing, surface treatment and medical applications. However the plasma operates in contact with air, thus species like oxygen and nitrogen diffuse

RF-plasma vapor deposition of siloxane on paper. Part 1: Physical evolution of paper surface

Science.gov (United States)

Sahin, Halil Turgut

2013-01-01

An alternative, new approach to improve the hydrophobicity and barrier properties of paper was evaluated by radio-frequency (RF) plasma octamethylcyclotetrasiloxane (OMCTSO) vapor treatment. The interaction between OMCTSO and paper, causing the increased hydophobicity, is likely through covalent bonding. The deposited thin silicone-like polymeric layer from OMCTSO plasma treatment possessed desirable hydrophobic properties. The SEM micrographs showed uniformly distributed grainy particles with various shapes on the paper surface. Deposition of the silicone polymer-like layer with the plasma treatment affects the distribution of voids in the network structure and increases the barrier against water intake and air. The water absorptivity was reduced by 44% for the OMCTSO plasma treated sheet. The highest resistance to air flow was an approximately 41% lower air permeability than virgin paper.

CASTOR {sup registered} HAW28M - a high heat load cask for transport and storage of vitrified high level waste containers

Energy Technology Data Exchange (ETDEWEB)

Vossnacke, A.; Klein, K.; Kuehne, B. [GNS Gesellschaft fuer Nuklear-Service mbH/GNB, Essen (Germany)

2004-07-01

Within the German return programme for vitrified high level waste (HLW) from reprocessing at COGEMA and BNFL up to now 39 casks loaded with 28 containers each were transported back to Germany and are stored in the Interim Storage Facility Gorleben (TBL-G) for up to 40 years. For transport and storage in all but one case the GNB casks CASTOR {sup registered} HAW 20/28 CG have been used. This cask type is designed to accommodate 20 or 28 HLW containers with a total thermal power of 45 kW maximum. In the near future, among the high level waste, which has to be returned to Germany, there will be an increasing number of containers of which the heat capacity and radioactive inventory will exceed the technical limits of the CASTOR {sup registered} HAW 20/28 CG. Therefore GNB has started the development of a new cask generation, named CASTOR {sup registered} HAW28M, meeting these future requirements. The CASTOR {sup registered} HAW28M is especially developed for the transport of vitrified residues from France and Great Britain to Germany. It complies with the international regulations for type B packages according to IAEA (International Atomic Energy Agency). It is thus guaranteed that even in case of any accident the cask body and the lid system remain functional and the safe confinement of the radioactive contents remains intact during transport. The CASTOR {sup registered} HAW28M fulfills not only the requirements for transport but also the acceptance criteria of interim storage: radiation shielding, heat dissipation, safe confinement under both normal and hypothetical accident conditions. Storage buildings such as the TBL-G simply support the safety functions of the cask. The challenge for the development results from higher requirements of the technical specification, particularly related to fuel which is reprocessed. As a consequence of the reprocessing of fuel with increased enrichment and burn up, higher heat capacity and sophisticated shielding measures have to be

Initiation of an early-stage plasma during picosecond laser ablation of solids

International Nuclear Information System (INIS)

Mao, Samuel S.; Mao, Xianglei; Greif, Ralph; Russo, Richard E.

2000-01-01

Picosecond time-resolved images of plasma initiation were recorded during pulsed-laser ablation of metal targets in an air atmosphere. An early-stage plasma was observed to form before the release of a material vapor plume. Close to the target surface, interferometry measurements indicate that the early-stage plasma has an electron number density on the order of 10 20 cm -3 . The longitudinal expansion of the ionization front for this plasma has a velocity 10 9 cm/s, during the laser pulse. In contrast, a material--vapor plume forms approximately 200 ps after the laser pulse, and it moves away from the target at 10 6 cm/s. The experimental observations of the early-stage plasma were simulated by using a theoretical model based on a two-fluids description of laser plasmas. The results indicate that the initiation of the plasma is due to air breakdown assisted by electron emission from the target

Overview of plasma technology used in medicine

Science.gov (United States)

Ryan, Thomas P.; Stalder, Kenneth R.; Woloszko, Jean

2013-02-01

Plasma Medicine is a growing field that is having an impact in several important areas in therapeutic patient care, combining plasma physics, biology, and clinical medicine. Historically, plasmas in medicine were used in electrosurgery for cautery and non-contact hemostasis. Presently, non-thermal plasmas have attained widespread use in medicine due to their effectiveness and compatibility with biological systems. The paper will give a general overview of how low temperature, non-equilibrium, gas plasmas operate, both from physics and biology perspectives. Plasma is commonly described as the fourth state of matter and is typically comprised of charged species, active molecules and atoms, as well as a source of UV and photons. The most active areas of plasma technology applications are in wound treatment; tissue regeneration; inactivation of pathogens, including biofilms; treating skin diseases; and sterilization. There are several means of generating plasmas for use in medical applications, including plasma jets, dielectric barrier discharges, capacitively or inductively coupled discharges, or microplasmas. These systems overcome the former constraints of high vacuum, high power requirements and bulky systems, into systems that use room air and other gases and liquids at low temperature, low power, and hand-held operation at atmospheric pressure. Systems will be discussed using a variety of energy sources: pulsed DC, AC, microwave and radiofrequency, as well as the range of frequency, pulse duration, and gas combinations in an air environment. The ionic clouds and reactive species will be covered in terms of effects on biological systems. Lastly, several commercial products will be overviewed in light of the technology utilized, health care problems being solved, and clinical trial results.

Study of nanosecond discharges in H2-air mixtures at atmospheric pressure for plasma assisted combustion applications

Science.gov (United States)

Kobayashi, Sumire; Bonaventura, Zdeněk; Tholin, Fabien; Popov, Nikolay A.; Bourdon, Anne

2017-07-01

This paper presents 2D simulations of nanosecond discharges between two point electrodes for four different H2-air mixtures defined by their equivalence ratios ϕ (i.e. φ =0, air, φ =0.3, lean mixture, φ =1, stoichiometric mixture and φ =1.5, rich mixture) at atmospheric pressure and at an initial temperature of 1000 K. In a first step, we have shown that the mixture composition has only a very small influence on the discharge dynamics and structure during the streamer phase and up to the formation of the plasma channel between the two point electrodes in H2-air mixtures with φ \\in [0,1.5]. However, as the plasma channel is formed slightly earlier as the equivalence ratio increases, for a given voltage pulse, the duration of the nanosecond spark phase increases as the equivalence ratio increases. As expected, we have shown that excited states of N2 (and in particular N2(A)) and radicals (and in particular O(D), O(P), H and OH) are very efficiently produced during the voltage pulse after the start of the spark phase. After the voltage pulse, and up to 100 ns, the densities of excited states of N2 and of O(D) decrease. Conversely, most of the O(P), H and OH radicals are produced after the voltage pulse due to the dissociative quenching of electronically excited N2. As for radicals, the gas temperature starts increasing after the start of the spark phase. For all studied mixtures, the density of O(P) atoms and the gas temperature reach their maxima after the end of the voltage pulse and the densities of O(P), H and OH radicals and the maximal gas temperature increase as the equivalence ratio increases. We have shown that the production of radicals is the highest on the discharge axis and the distribution of species after the voltage pulse and up to 100 ns has a larger diameter between the electrodes than close to both electrode tips. As for species, the temperature distribution presents two hot spots close to the point electrode tips. The non

Analysis of high-level radioactive slurries as a method to reduce DWPF turnaround times

International Nuclear Information System (INIS)

Coleman, C.J.; Bibler, N.E.; Ferrara, D.M.; Hay, M.S.

1996-01-01

Analysis of Defense Waste Processing Facility (DWPF) samples as slurries rather than as dried or vitrified samples is an effective way to reduce sample turnaround times. Slurries can be dissolved with a mixture of concentrated acids to yield solutions for elemental analysis by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Slurry analyses can be performed in eight hours, whereas analyses of vitrified samples require up to 40 hours to complete. Analyses of melter feed samples consisting of the DWPF borosilicate frit and either simulated or actual DWPF radioactive sludge were typically within a range of 3--5% of the predicted value based on the relative amounts of sludge and frit added to the slurry. The results indicate that the slurry analysis approach yields analytical accuracy and precision competitive with those obtained from analyses of vitrified samples. Slurry analyses offer a viable alternative to analyses of solid samples as a simple way to reduce analytical turnaround times

Influence of O2 or H2O in a plasma jet and its environment on plasma electrical and biochemical performances

Science.gov (United States)

Adhikari, Ek R.; Samara, Vladimir; Ptasinska, Sylwia

2018-05-01

Because environmental conditions, such as room temperature and humidity, fluctuate arbitrarily, effects of atmospheric pressure plasma jets (APPJs) used in medical applications operating at various places and time might vary. Therefore, understanding the possible effects of air components in and outside APPJs is essential for clinical use, which requires reproducibility of plasma performance. These air components can influence the formation of reactive species in the APPJ, and the type and amount of these species formed depend on the feed gas inside the APPJ and the plasma jet environment. In this study, we monitored changes in plasma current and power, as well as in the level of DNA damage attributable to plasma irradiation, by adjusting the fraction of oxygen and water vapor in the plasma jet environment and feed gas. Here, DNA was used as a molecular probe to identify chemical changes that occurred in the plasma jet under these various environmental conditions. The damaged and undamaged fractions of DNA were quantified using agarose gel electrophoresis. We obtained an optimal amount of oxygen or water vapor in the plasma jet environment, as well as in the feed gas, which increased the level of DNA damage significantly. This increase can be attributed primarily to the formation of reactive species caused by water and oxygen decomposition in the APPJ detected with mass spectrometry. Moreover, we observed that the plasma power remained the same or decreased when gas was added to the jet environment or the feed gas, respectively, but in both cases, DNA damage increased. This indicates the superiority of plasma chemistry over the electrical power applied for APPJ ignition of the plasma sources used in medical applications.

Interferometric and schlieren characterization of the plasmas and shock wave dynamics during laser-triggered discharge in atmospheric air

Energy Technology Data Exchange (ETDEWEB)

Wei, Wenfu; Li, Xingwen, E-mail: xwli@mail.xjtu.edu.cn; Wu, Jian; Yang, Zefeng; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Shaanxi 710049 (China)

2014-08-15

This paper describes our efforts to reveal the underlying physics of laser-triggered discharges in atmospheric air using a Mach-Zehnder interferometer and schlieren photography. Unlike the hemispherical shock waves that are produced by laser ablation, bell-like morphologies are observed during laser-triggered discharges. Phase shifts are recovered from the interferograms at a time of 1000 ns by the 2D fast Fourier transform method, and then the values of the refractive index are deduced using the Abel inversion. An abundance of free electrons is expected near the cathode surface. The schlieren photographs visualize the formation of stagnation layers at ∼600 ns in the interaction zones of the laser- and discharge-produced plasmas. Multiple reflected waves are observed at later times with the development of shock wave propagations. Estimations using the Taylor-Sedov self-similar solution indicated that approximately 45.8% and 51.9% of the laser and electrical energies are transferred into the gas flow motions, respectively. Finally, numerical simulations were performed, which successfully reproduced the main features of the experimental observations, and provided valuable insights into the plasma and shock wave dynamics during the laser-triggered discharge.

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

International Nuclear Information System (INIS)

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

2013-01-01

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

Air ions and aerosol science

International Nuclear Information System (INIS)

Tammet, H.

1996-01-01

Collaboration between Gas Discharge and Plasma Physics, Atmospheric Electricity, and Aerosol Science is a factor of success in the research of air ions. The concept of air ion as of any carrier of electrical current through the air is inherent to Atmospheric Electricity under which a considerable statistical information about the air ion mobility spectrum is collected. A new model of air ion size-mobility correlation has been developed proceeding from Aerosol Science and joining the methods of neighboring research fields. The predicted temperature variation of the mobility disagrees with the commonly used Langevin rule for the reduction of air ion mobilities to the standard conditions. Concurrent errors are too big to be neglected in applications. The critical diameter distinguishing cluster ions and charged aerosol particles has been estimated to be 1.4 endash 1.8 nm. copyright 1996 American Institute of Physics

A plasma needle generates nitric oxide

International Nuclear Information System (INIS)

Stoffels, E; Gonzalvo, Y Aranda; Whitmore, T D; Seymour, D L; Rees, J A

2006-01-01

Generation of nitric oxide (NO) by a plasma needle is studied by means of mass spectrometry. The plasma needle is an atmospheric glow generated by a radio-frequency excitation in a mixture of helium and air. This source is used for the treatment of living tissues, and nitric oxide may be one of the most important active agents in plasma therapy. Efficient NO generation is of particular importance in the treatment of cardiovascular diseases. Mass spectrometric measurements have been performed under various plasma conditions; gas composition in the plasma and conversion of feed gases (nitrogen and oxygen) into other species has been studied. Up to 30% of the N 2 and O 2 input is consumed in the discharge, and NO has been identified as the main conversion product

Plasma–catalyst coupling for volatile organic compound removal and indoor air treatment: a review

International Nuclear Information System (INIS)

Thevenet, F; Sivachandiran, L; Guaitella, O; Barakat, C; Rousseau, A

2014-01-01

The first part of the review summarizes the problem of air pollution and related air-cleaning technologies. Volatile organic compounds in particular have various effects on health and their abatement is a key issue. Different ways to couple non-thermal plasmas with catalytic or adsorbing materials are listed. In particular, a comparison between in-plasma and post-plasma coupling is made. Studies dealing with plasma-induced heterogeneous reactivity are analysed, as well as the possible modifications of the catalyst surface under plasma exposure. As an alternative to the conventional and widely studied plasma–catalyst coupling, a sequential approach has been recently proposed whereby pollutants are first adsorbed onto the material, then oxidized by switching on the plasma. Such a sequential approach is reviewed in detail. (paper)

Influence of plasma treatment on corn germination and early growth

Czech Academy of Sciences Publication Activity Database

Šerá, Božena; Špatenka, P.; Šerý, M.; Vrchotová, Naděžda; Hrušková, Iveta

2010-01-01

Roč. 38, č. 10 (2010), s. 2963-2968 ISSN 0093-3813 Institutional research plan: CEZ:AV0Z60870520 Keywords : air plasma * germination * microwave discharge * seed Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.070, year: 2010

Modification of polycarbonate surface in oxidizing plasma

Science.gov (United States)

Ovtsyn, A. A.; Smirnov, S. A.; Shikova, T. G.; Kholodkov, I. V.

2017-11-01

The properties of the surface of the film polycarbonate Lexan 8010 were experimentally studied after treatment in a DC discharge plasma in oxygen and air at pressures of 50-300 Pa and a discharge current of 80 mA. The contact angles of wetting and surface energies are measured. The topography of the surface was investigated by atomic force microscopy. The chemical composition of the surface was determined from the FT-IR spectroscopy data in the variant of total internal reflection, as well as X-ray photoelectron spectroscopy. Treatment in the oxidizing plasma leads to a change in morphology (average roughness increases), an increase in the surface energy, and the concentration of oxygen-containing groups (hydroxyl groups, carbonyl groups in ketones or aldehydes and in oxyketones) on the surface of the polymer. Possible reasons for the difference in surface properties of polymer under the action of oxygen and air plasma on it are discussed.

A Nanosecond Pulsed Plasma Brush for Surface Decontamination

Science.gov (United States)

Neuber, Johanna; Malik, Muhammad; Song, Shutong; Jiang, Chunqi

2015-11-01

This work optimizes a non-thermal, atmospheric pressure plasma brush for surface decontamination. The generated plasma plumes with a maximum length of 2 cm are arranged in a 5 cm long, brush-like array. The plasma was generated in ambient air with Acinetobacter baumannii. Laminate surfaces inoculated with over-night cultured bacteria were subject to the plasma treatment for varying water concentrations in He, flow rates and discharge voltages. It was found that increasing the water content of the feed gas greatly enhanced the bactericidal effect. Emission spectroscopy was performed to identify the reactive plasma species that contribute to this variation. Additional affiliation: Frank Reidy Research Center for Bioelectrics

The AMY experiment: Microwave emission from air shower plasmas

Directory of Open Access Journals (Sweden)

Alvarez-Muñiz J.

2016-01-01

Full Text Available You The Air Microwave Yield (AMY experiment investigate the molecular bremsstrahlung radiation emitted in the GHz frequency range from an electron beam induced air-shower. The measurements have been performed at the Beam Test Facility (BTF of Frascati INFN National Laboratories with a 510 MeV electron beam in a wide frequency range between 1 and 20 GHz. We present the apparatus and the results of the tests performed.

Research on Permeability of Poly(ethylene) Terephthalate Track Membranes Modified in Plasma

CERN Document Server

Dmitriev, S N; Sleptsov, V V; Elinson, V M; Potrjasaj, V V

2001-01-01

The properties of poly(ethylene) terephthalate track membranes subjected to the plasma RF-discharge treatment in air have been investigated. The effect of the treatment conditions in plasma on the structure and the properties of the membranes formed in the gas-discharge etching has been studied. It has been figured out that the influence of the air plasma on the membranes under study leads to a formation of asymmetric membranes with a higher flow rate, the structure and chemical composition of their superficial layer are changed. It is shown that the presence of the modified layer on the surface of the membranes causes changing their hydrodynamic characteristics - water permeability of the membranes treated in plasma in a greater degree depends upon {pH} of the filtered solution.

Energy Accommodation from Surface Catalyzed Reactions in Air Plasmas

Data.gov (United States)

National Aeronautics and Space Administration — Understanding energy transport at the gas-surface interface between catalytic/reacting surfaces exposed to highly dissociated plasmas remains a significant research...

Three-dimensional effects of curved plasma actuators in quiescent air

International Nuclear Information System (INIS)

Wang Chincheng; Durscher, Ryan; Roy, Subrata

2011-01-01

This paper presents results on a new class of curved plasma actuators for the inducement of three-dimensional vortical structures. The nature of the fluid flow inducement on a flat plate, in quiescent conditions, due to four different shapes of dielectric barrier discharge (DBD) plasma actuators is numerically investigated. The three-dimensional plasma kinetic equations are solved using our in-house, finite element based, multiscale ionized gas (MIG) flow code. Numerical results show electron temperature and three dimensional plasma force vectors for four shapes, which include linear, triangular, serpentine, and square actuators. Three-dimensional effects such as pinching and spreading the neighboring fluid are observed for serpentine and square actuators. The mechanisms of vorticity generation for DBD actuators are discussed. Also the influence of geometric wavelength (λ) and amplitude (Λ) of the serpentine and square actuators on vectored thrust inducement is predicted. This results in these actuators producing significantly better flow mixing downstream as compared to the standard linear actuator. Increasing the wavelengths of serpentine and square actuators in the spanwise direction is shown to enhance the pinching effect giving a much higher vertical velocity. On the contrary, changing the amplitude of the curved actuator varies the streamwise velocity significantly influencing the near wall jet. Experimental data for a serpentine actuator are also reported for validation purpose.

FY-97 operations of the pilot-scale glass melter to vitrify simulated ICPP high activity sodium-bearing waste

International Nuclear Information System (INIS)

Musick, C.A.

1997-11-01

A 3.5 liter refractory-lined joule-heated glass melter was built to test the applicability of electric melting to vitrify simulated high activity waste (HAW). The HAW streams result from dissolution and separation of Idaho Chemical Processing Plant (ICPP) calcines and/or radioactive liquid waste. Pilot scale melter operations will establish selection criteria needed to evaluate the application of joule heating to immobilize ICPP high activity waste streams. The melter was fabricated with K-3 refractory walls and Inconel 690 electrodes. It is designed to be continuously operated at 1,150 C with a maximum glass output rate of 10 lbs/hr. The first set of tests were completed using surrogate HAW-sodium bearing waste (SBW). The melter operated for 57 hours and was shut down due to excessive melt temperatures resulting in low glass viscosity (< 30 Poise). Due to the high melt temperature and low viscosity the molten glass breached the melt chamber. The melter has been dismantled and examined to identify required process improvement areas and successes of the first melter run. The melter has been redesigned and is currently being fabricated for the second run, which is scheduled to begin in December 1997