WorldWideScience

Sample records for atmospheric pressure plasmas

  1. Atmospheric Pressure Plasma Process And Applications

    Energy Technology Data Exchange (ETDEWEB)

    Peter C. Kong; Myrtle

    2006-09-01

    This paper provides a general discussion of atmospheric-pressure plasma generation, processes, and applications. There are two distinct categories of atmospheric-pressure plasmas: thermal and nonthermal. Thermal atmospheric-pressure plasmas include those produced in high intensity arcs, plasma torches, or in high intensity, high frequency discharges. Although nonthermal plasmas are at room temperatures, they are extremely effective in producing activated species, e.g., free radicals and excited state atoms. Thus, both thermal and nonthermal atmosphericpressure plasmas are finding applications in a wide variety of industrial processes, e.g. waste destruction, material recovery, extractive metallurgy, powder synthesis, and energy conversion. A brief discussion of recent plasma technology research and development activities at the Idaho National Laboratory is included.

  2. Formation Mechanism of Atmospheric Pressure Plasma Jet

    CERN Document Server

    Jiang, Nan; Cao, Zexian

    2008-01-01

    Atmospheric pressure plasma jet can protrude some 5.0 cm into air. It holds promise for multivarious innovative applications, but its formation mechanism remains unsettled. We show that the plasma jet is essentially a streamer corona totally independent of, but obscured by, dielectric barrier discharge. Consequently, the jets can be equally successfully generated even with one single bare metal electrode attached to the tube orifice, both downstream and upstream simultaneously, and at a significantly reduced voltage. These results will help understand the underlying physics and facilitate a safer and more flexible implementation of this marvelous plasma source.

  3. Atmospheric Pressure Plasma Processing for Polymer Adhesion: A Review

    DEFF Research Database (Denmark)

    Kusano, Yukihiro

    2014-01-01

    Atmospheric pressure plasma processing has attracted significant interests over decades due to its usefulness and a variety of applications. Adhesion improvement of polymer surfaces is among the most important applications of atmospheric pressure plasma treatment. Reflecting recent significant...... development of the atmospheric pressure plasma processing, this work presents its fundamental aspects, applications, and characterization techniques relevant to adhesion....

  4. New development of atmospheric pressure plasma polishing

    Institute of Scientific and Technical Information of China (English)

    Bo Wang; Jufan Zhang; Shen Dong

    2009-01-01

    Atmospheric pressure plasma polishing (APPP) is a precision machining technology used for manufacturing high quality optical surfaces. The changes of surface modulus and hardness after machining prove the distinct improvement of surface mechanical properties. The demonstrated decrease of surfacc residual stresses testifies the removal of the former deformation layer.And the surface topographies under atomic force microscope (AFM) and scanning electron microscope (SEM) indicate obvious amelioration of the surface status,showing that the 0.926-nm average surface roughness has been achieved.

  5. A New Atmospheric Pressure Microwave Plasma Source (APMPS)

    Institute of Scientific and Technical Information of China (English)

    LIU Liang; ZHANG Guixin; LI Yinan; ZHU Zhijie; WANG Xinxin; LUO Chengmu

    2008-01-01

    An atmospheric pressure microwave plasma source (APMPS) that can generate a large volume of plasma at an atmospheric pressure has been developed at Tsinghua University. This paper presents the design of this APMPS, the theoretical consideration of microwave plasma ignition and the simulation results, including the distributions of the electric field and power density inside the cavity as well as the accuracy of the simulation results. In addition, a method of producing an atmospheric pressure microwave plasma and some relevant observations of the plasma are also provided. It. is expected that this research would be useful for further developing atmospheric pressure microwave plasma sources and expanding the scope of their applications.

  6. Atmospheric pressure plasma for surface modification

    CERN Document Server

    Wolf, Rory A

    2012-01-01

    This Book's focus and intent is to impart an understanding of the practical application of atmospheric plasma for the advancement of a wide range of current and emerging technologies. The primary key feature of this book is the introduction of over thirteen years of practical experimental evidence of successful surface modifications by atmospheric plasma methods. It offers a handbook-based approach for leveraging and optimizing atmospheric plasma technologies which are currently in commercial use. It also offers a complete treatment of both basic plasma physics and industrial plasma process

  7. 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.

  8. Electrode Configurations in Atmospheric Pressure Plasma Jets

    Science.gov (United States)

    Lietz, Amanda M.; Kushner, Mark J.

    2016-09-01

    Atmospheric pressure plasma jets (APPJs) are being studied for emerging medical applications including cancer treatment and wound healing. APPJs typically consist of a dielectric tube through which a rare gas flows, sometimes with an O2 or H2O impurity. In this paper, we present results from a computational study of APPJs using nonPDPSIM, a 2-D plasma hydrodynamics model, with the goal of providing insights on how the placement of electrodes can influence the production of reactive species. Gas consisting of He/O2 = 99.5/0.5 is flowed through a capillary tube at 2 slpm into humid air, and a pulsed DC voltage is applied. An APPJ with two external ring electrodes will be compared with one having a powered electrode inside and a ground electrode on the outside. The consequences on ionization wave propagation and the production of reactive oxygen and nitrogen species (RONS) will be discussed. Changing the electrode configuration can concentrate the power deposition in volumes having different gas composition, resulting in different RONS production. An internal electrode can result in increased production of NOx and HNOx by increasing propagation of the ionization wave through the He dominated plume to outside of the tube where humid air is diffusing into the plume. Work supported by US DOE Office of Fusion Energy Science and the National Science Foundation.

  9. Non-Thermal Sanitation By Atmospheric Pressure Plasma Project

    Data.gov (United States)

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

  10. Non-Thermal Sanitation By Atmospheric Pressure Plasma Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC's Non-Thermal Sanitation by Atmospheric Pressure Plasma technology sanitizes fresh fruits and vegetables without the use of consumable chemicals and without...

  11. Surface cleaning of metal wire by atmospheric pressure plasma

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, T., E-mail: tsubasa@oshima-k.ac.jp [Electronic-Mechanical Engineering Department, Oshima National College of Maritime Technology, 1091-1 Komatsu, Suo-Oshima, Yamaguchi (Japan); Department of Electrical Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka (Japan); Buttapeng, C. [School of Electrical and Energy Engineering, University of the Thai Chamber of Commerce, 126/1, Vibhavadee-Rungsit, Dindaeng, Bangkok 10400 (Thailand); Furuya, S. [Faculty of Education, Gunma University, 4-2 Aramaki, Maebashi (Japan); Harada, N. [Department of Electrical Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka (Japan)

    2009-11-30

    In this study, the possible application of atmospheric pressure dielectric barrier discharge plasma for the annealing of metallic wire is examined and presented. The main purpose of the current study is to examine the surface cleaning effect for a cylindrical object by atmospheric pressure plasma. The experimental setup consists of a gas tank, plasma reactor, and power supply with control panel. The gas assists in the generation of plasma. Copper wire was used as an experimental cylindrical object. This copper wire was irradiated with the plasma, and the cleaning effect was confirmed. The result showed that it is possible to remove the tarnish which exists on the copper wire surface. The experiment reveals that atmospheric pressure plasma is usable for the surface cleaning of metal wire. However, it is necessary to examine the method for preventing oxidization of the copper wire.

  12. MicroScale - Atmospheric Pressure Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Sankaran, Mohan [Case Western Reserve University

    2012-01-25

    Low-temperature plasmas play an essential role in the manufacturing of integrated circuits which are ubiquitous in modern society. In recent years, these top-down approaches to materials processing have reached a physical limit. As a result, alternative approaches to materials processing are being developed that will allow the fabrication of nanoscale materials from the bottom up. The aim of our research is to develop a new class of plasmas, termed “microplasmas” for nanomaterials synthesis. Microplasmas are a special class of plasmas formed in geometries where at least one dimension is less than 1 mm. Plasma confinement leads to several unique properties including high-pressure stability and non-equilibrium that make microplasams suitable for nanomaterials synthesis. Vapor-phase precursors can be dissociated to homogeneously nucleate nanometer-sized metal and alloyed nanoparticles. Alternatively, metal salts dispersed in liquids or polymer films can be electrochemically reduced to form metal nanoparticles. In this talk, I will discuss these topics in detail, highlighting the advantages of microplasma-based systems for the synthesis of well-defined nanomaterials.

  13. Decomposition of Chemical Chain Molecules with Atmospheric Pressure Plasma

    Science.gov (United States)

    Tansli, Murat; Tasal, Erol

    2016-10-01

    Chemical chain molecules' decomposition is an interesting subject area for the atmospheric pressure plasma applications. The effects of the atmospheric pressure argon plasma on 4-((2-methoxyphenyl)Diazenyl)Benzene-1,3,-Diol molecule at room temperature are investigated. This molecule is one of the industrial dye molecules used widely. When considering the ecological life, this molecule will be very harmful and danger. We suggest a different, easy and useful decomposing method for such molecules. Atmospheric pressure plasma jet was principally treated for this decomposing of the molecule. Fourier transform infrared spectrometry (FT-IR) was used to characterization of the molecule after the plasma application to molecule in liquid phase with ethanol and methanol solvents. The atmospheric-pressure plasma jet of argon (Ar) as non-equilibrium has been formed by ac-power generator with frequency - 24 kHz and voltage - 12 kV. Characterizations for solutions prepared with ethanol and methanol solvents of molecule have been examined after applying (duration: 3 minutes) the atmospheric pressure plasma jet. The molecule was broken at 6C-7N =8N-9C stretching peak after the plasma treatment. The new plasma photo-products for ethanol and methanol solutions were produced as 6C-7N-8N =9C (strong, varying) and 12C =17O (strong, wide) stretching peaks.

  14. Ultrasound enhanced plasma surface modification at atmospheric pressure

    DEFF Research Database (Denmark)

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

    2012-01-01

    Efficiency of atmospheric pressure plasma treatment can be highly enhanced by simultaneous high power ultrasonic irradiation onto the treating surface. It is because ultrasonic waves with a sound pressure level (SPL) above ∼140 dB can reduce the thickness of a boundary gas layer between the plasma...... arc at atmospheric pressure to study adhesion improvement. The effect of ultrasonic irradiation with the frequency diapason between 20 and 40 kHz at the SPL of ∼150 dB was investigated. After the plasma treatment without ultrasonic irradiation, the wettability was significantly improved...

  15. Nanocapillary Atmospheric Pressure Plasma Jet: A Tool for Ultrafine Maskless Surface Modification at Atmospheric Pressure.

    Science.gov (United States)

    Motrescu, Iuliana; Nagatsu, Masaaki

    2016-05-18

    With respect to microsized surface functionalization techniques we proposed the use of a maskless, versatile, simple tool, represented by a nano- or microcapillary atmospheric pressure plasma jet for producing microsized controlled etching, chemical vapor deposition, and chemical modification patterns on polymeric surfaces. In this work we show the possibility of size-controlled surface amination, and we discuss it as a function of different processing parameters. Moreover, we prove the successful connection of labeled sugar chains on the functionalized microscale patterns, indicating the possibility to use ultrafine capillary atmospheric pressure plasma jets as versatile tools for biosensing, tissue engineering, and related biomedical applications.

  16. Spacecraft Sterilization Using Non-Equilibrium Atmospheric Pressure Plasma

    Science.gov (United States)

    Cooper, Moogega; Vaze, Nachiket; Anderson, Shawn; Fridman, Gregory; Vasilets, Victor N.; Gutsol, Alexander; Tsapin, Alexander; Fridman, Alexander

    2007-01-01

    As a solution to chemically and thermally destructive sterilization methods currently used for spacecraft, non-equilibrium atmospheric pressure plasmas are used to treat surfaces inoculated with Bacillus subtilis and Deinococcus radiodurans. Evidence of significant morphological changes and reduction in viability due to plasma exposure will be presented, including a 4-log reduction of B. subtilis after 2 minutes of dielectric barrier discharge treatment.

  17. Atmospheric pressure plasma enhanced spatial ALD of silver

    NARCIS (Netherlands)

    Van Den Bruele, F.J.; Smets, M.; Illiberi, A.; Creyghton, Y.; Buskens, P.; Roozeboom, F.; Poodt, P.

    2014-01-01

    The authors have investigated the growth of thin silver films using a unique combination of atmospheric process elements: spatial atomic layer deposition and an atmospheric pressure surface dielectric barrier discharge plasma source. Silver films were grown on top of Si substrates with good purity a

  18. Ultrasound enhanced plasma surface modification at atmospheric pressure

    DEFF Research Database (Denmark)

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

    Atmospheric pressure plasma treatment can be highly enhanced by simultaneous high-power ultrasonic irradiation onto the treating surface. It is because ultrasonic waves with a sound pressure level (SPL) above approximately 140 dB can reduce the thickness of a boundary gas layer between the plasma...... and the material surface, and thus many reactive species generated in the plasma can reach the surface before inactivated, and be efficiently utilized for surface modification. In the present work polyester plates are treated using a dielectric barrier discharge (DBD) and a gliding arc at atmospheric pressure...... irradiation, the water contact angle dropped markedly, and tended to decrease furthermore at higher power. The ultrasonic irradiation during the plasma treatment consistently improved the wettability. Oxygen containing polar functional groups were introduced at the surface by the plasma treatment...

  19. Cellular membrane collapse by atmospheric-pressure plasma jet

    Science.gov (United States)

    Kim, Kangil; Jun Ahn, Hak; Lee, Jae-Hyeok; Kim, Jae-Ho; Sik Yang, Sang; Lee, Jong-Soo

    2014-01-01

    Cellular membrane dysfunction caused by air plasma in cancer cells has been studied to exploit atmospheric-pressure plasma jets for cancer therapy. Here, we report that plasma jet treatment of cervical cancer HeLa cells increased electrical conductivity across the cellular lipid membrane and caused simultaneous lipid oxidation and cellular membrane collapse. We made this finding by employing a self-manufactured microelectrode chip. Furthermore, increased roughness of the cellular lipid membrane and sequential collapse of the membrane were observed by atomic force microscopy following plasma jet treatment. These results suggest that the cellular membrane catastrophe occurs via coincident altered electrical conductivity, lipid oxidation, and membrane roughening caused by an atmospheric-pressure plasma jet, possibly resulting in cellular vulnerability to reactive species generated from the plasma as well as cytotoxicity to cancer cells.

  20. Cellular membrane collapse by atmospheric-pressure plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kangil; Sik Yang, Sang, E-mail: jsjlee@ajou.ac.kr, E-mail: ssyang@ajou.ac.kr [Department of Electrical and Computer Engineering, Ajou University, Suwon 443-749 (Korea, Republic of); Jun Ahn, Hak; Lee, Jong-Soo, E-mail: jsjlee@ajou.ac.kr, E-mail: ssyang@ajou.ac.kr [Department of Biological Sciences, Ajou University, Suwon 443-749 (Korea, Republic of); Lee, Jae-Hyeok; Kim, Jae-Ho [Department of Molecular Science and Technology, Ajou University, Suwon 443-749 (Korea, Republic of)

    2014-01-06

    Cellular membrane dysfunction caused by air plasma in cancer cells has been studied to exploit atmospheric-pressure plasma jets for cancer therapy. Here, we report that plasma jet treatment of cervical cancer HeLa cells increased electrical conductivity across the cellular lipid membrane and caused simultaneous lipid oxidation and cellular membrane collapse. We made this finding by employing a self-manufactured microelectrode chip. Furthermore, increased roughness of the cellular lipid membrane and sequential collapse of the membrane were observed by atomic force microscopy following plasma jet treatment. These results suggest that the cellular membrane catastrophe occurs via coincident altered electrical conductivity, lipid oxidation, and membrane roughening caused by an atmospheric-pressure plasma jet, possibly resulting in cellular vulnerability to reactive species generated from the plasma as well as cytotoxicity to cancer cells.

  1. Characteristics of RF Cold Plasma at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    QIU Liang; MENG Yuedong; SHU Xingsheng

    2007-01-01

    The characteristics of a stable discharge at atmospheric pressure is investigated.The plasma source consisted of two closely spaced parallel-plated perforated electrodes,driven by a radio frequency power to generate a uniform cold plasma in Helium at atmospheric pressure.Both alpha and gamma modes were clearly observed.The hollow cathode effects were found in the discharge.The influence of the dielectric barrier on the discharge was also investigated by utilizing a surface-anodized aluminium electrode as the anode.

  2. Stimulation of wound healing by helium atmospheric pressure plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Nastuta, Andrei Vasile; Topala, Ionut; Pohoata, Valentin; Popa, Gheorghe [Faculty of Physics, Alexandru Ioan Cuza University, Bd. Carol No. 11, 700506, Iasi (Romania); Grigoras, Constantin, E-mail: andrei.nastuta@uaic.ro [Physiopathology Department, Grigore T. Popa University of Medicine and Pharmacy, 700115, Iasi (Romania)

    2011-03-16

    New experiments using atmospheric pressure plasma have found large application in treatment of living cells or tissues, wound healing, cancerous cell apoptosis, blood coagulation on wounds, bone tissue modification, sterilization and decontamination. In this study an atmospheric pressure plasma jet generated using a cylindrical dielectric-barrier discharge was applied for treatment of burned wounds on Wistar rats' skin. The low temperature plasma jet works in helium and is driven by high voltage pulses. Oxygen and nitrogen based impurities are identified in the jet by emission spectroscopy. This paper analyses the natural epithelization of the rats' skin wounds and two methods of assisted epithelization, a classical one using polyurethane wound dressing and a new one using daily atmospheric pressure plasma treatment of wounds. Systemic and local medical data, such as haematological, biochemical and histological parameters, were monitored during entire period of study. Increased oxidative stress was observed for plasma treated wound. This result can be related to the presence in the plasma volume of active species, such as O and OH radicals. Both methods, wound dressing and plasma-assisted epithelization, provided positive medical results related to the recovery process of burned wounds. The dynamics of the skin regeneration process was modified: the epidermis re-epitelization was accelerated, while the recovery of superficial dermis was slowed down.

  3. Stimulation of wound healing by helium atmospheric pressure plasma treatment

    Science.gov (United States)

    Vasile Nastuta, Andrei; Topala, Ionut; Grigoras, Constantin; Pohoata, Valentin; Popa, Gheorghe

    2011-03-01

    New experiments using atmospheric pressure plasma have found large application in treatment of living cells or tissues, wound healing, cancerous cell apoptosis, blood coagulation on wounds, bone tissue modification, sterilization and decontamination. In this study an atmospheric pressure plasma jet generated using a cylindrical dielectric-barrier discharge was applied for treatment of burned wounds on Wistar rats' skin. The low temperature plasma jet works in helium and is driven by high voltage pulses. Oxygen and nitrogen based impurities are identified in the jet by emission spectroscopy. This paper analyses the natural epithelization of the rats' skin wounds and two methods of assisted epithelization, a classical one using polyurethane wound dressing and a new one using daily atmospheric pressure plasma treatment of wounds. Systemic and local medical data, such as haematological, biochemical and histological parameters, were monitored during entire period of study. Increased oxidative stress was observed for plasma treated wound. This result can be related to the presence in the plasma volume of active species, such as O and OH radicals. Both methods, wound dressing and plasma-assisted epithelization, provided positive medical results related to the recovery process of burned wounds. The dynamics of the skin regeneration process was modified: the epidermis re-epitelization was accelerated, while the recovery of superficial dermis was slowed down.

  4. [Spectral diagnosis of plasma jet at atmospheric pressure].

    Science.gov (United States)

    Li, Chi; Tang, Xiao-liang; Qiu, Gao

    2008-12-01

    A new approach to surface modification of materials using dielectric barrier discharge (DBD) plasma jet at atmospheric pressure is presented in the present paper. The emission spectral lines of argon plasma jet at atmospheric pressure were recorded by the grating spectrograph HR2000 and computer software. The argon plasma emission spectra, ranging from 300nm to 1000 nm, were measured at different applied voltage. Compared to air plasma emission spectra under the same circumstance, it is shown that all of the spectral lines are attributed to neutral argon atoms. The spectral lines 763.51 and 772.42 nm were chosen to estimate the electron excitation temperature. The purpose of the study is to research the relationship between the applied voltage and temperature to control the process of materials' surface modification promptly. The results show that electron excitation temperature is in the range of 0.1-0.5 eV and increases with increasing applied voltage. In the process of surface modification under the plasma jet, the infrared radiation thermometer was used to measure the material surface temperature under the plasma jet. The results show that the material surface temperature is in the range of 50-100 degrees C and it also increases with increasing applied voltage. Because the material surface was under the plasma jet and its temperature was decided by the plasma, and the material surface temperature increased with increasing the macro-temperature of plasma jet, the relationship between the surface temperature and applied voltage indicates the relationship between the macro-temperature of the plasma jet and the applied voltage approximately. The experimental results indicate that DBD plasma jet at atmospheric pressure is a new approach to improving the quality of materials' surface modification, and spectral diagnosis has proved to be a kind of workable method by choosing suitable applied voltage.

  5. Atmospheric Pressure Plasma Based Flame Control and Diagnostics

    Science.gov (United States)

    2015-01-01

    TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Atmospheric Pressure Plasma Based Flame Control and Diagnostics 5a...to 10%)  Flame speed enhancement (>20%)  Extension of lean limit (factor of two)  Distributed ignition  Development of new diagnostics

  6. Atmospheric pressure plasma surface modification of carbon fibres

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Løgstrup Andersen, Tom; Michelsen, Poul

    2008-01-01

    Carbon fibres are continuously treated with dielectric barrier discharge plasma at atmospheric pressure in various gas conditions for adhesion improvement in mind. An x-ray photoelectron spectroscopic analysis indicated that oxygen is effectively introduced onto the carbon fibre surfaces by He, He...

  7. Atmospheric pressure plasma jet treatment of Salmonella Enteritidis inoculated eggshells.

    Science.gov (United States)

    Moritz, Maike; Wiacek, Claudia; Koethe, Martin; Braun, Peggy G

    2017-03-20

    Contamination of eggshells with Salmonella Enteritidis remains a food safety concern. In many cases human salmonellosis within the EU can be traced back to raw or undercooked eggs and egg products. Atmospheric pressure plasma is a novel decontamination method that can reduce a wide range of pathogens. The aim of this work was to evaluate the possibility of using an effective short time cold plasma treatment to inactivate Salmonella Enteritidis on the eggshell. Therefore, artificially contaminated eggshells were treated with an atmospheric pressure plasma jet under different experimental settings with various exposure times (15-300s), distances from the plasma jet nozzle to the eggshell surface (5, 8 or 12mm), feed gas compositions (Ar, Ar with 0.2, 0.5 or 1.0% O2), gas flow rates (5 and 7slm) and different inoculations of Salmonella Enteritidis (10(1)-10(6)CFU/cm(2)). Atmospheric pressure plasma could reduce Salmonella Enteritidis on eggshells significantly. Reduction factors ranged between 0.22 and 2.27 log CFU (colony-forming units). Exposure time and, particularly at 10(4)CFU/cm(2) inoculation, feed gas had a major impact on Salmonella reduction. Precisely, longer exposure times led to higher reductions and Ar as feed gas was more effective than ArO2 mixtures.

  8. Sterilization of Turmeric by Atmospheric Pressure Dielectric Barrier Discharge Plasma

    Science.gov (United States)

    Setareh, Salarieh; Davoud, Dorranian

    2013-11-01

    In this study atmospheric pressure dielectric barrier discharge (DBD) plasma has been employed for sterilizing dry turmeric powders. A 6 kV, 6 kHz frequency generator was used to generate plasma with Ar, Ar/O2, He, and He/O2 gases between the 5 mm gap of two quartz covered electrodes. The complete sterilization time of samples due to plasma treatment was measured. The most important contaminant of turmeric is bacillus subtilis. The results show that the shortest sterilization time of 15 min is achieved by exposing the samples to Ar/O2 plasma. Survival curves of samples are exponential functions of time and the addition of oxygen to plasma leads to a significant increase of the absolute value of time constant of the curves. Magnitudes of protein and DNA in treated samples were increased to a similar value for all samples. Taste, color, and solubility of samples were not changed after the plasma treatment.

  9. Plasma reactor for deposition of carbon nanowalls at atmospheric pressure

    Science.gov (United States)

    Dimitrov, Zh; Mitev, D.; Kiss'ovski, Zh

    2016-10-01

    In this study a novel plasma reactor for deposition of carbon nanowalls at atmospheric pressure is constructed and characterized. A low power microwave discharge is used as a plasma source and working gas of Ar/H2/CH4 gas mixture. The substrate is heated by plasma flame and its temperature is in the range 600-700 C. The chemical composition of the plasma and the gas mixture effect on the concentration of the various particles in the plasma is investigated by optical emission spectroscopy. The emission spectrum of the plasma jet in Ar/H2/CH4 mixture shows the presence of carbon (Swan band) and an intensive line of CH (388 nm), which are necessary species for deposition of carbon nanostructures. Additional voltage in the range from -20 V to -100 V is applied in order to ensure the vertical growth of graphene walls. Results of deposited carbon nanostructures on metal substrate are shown.

  10. Atmospheric pressure plasmas for aerosols processes in materials and environment

    Science.gov (United States)

    Borra, J. P.; Jidenko, N.; Bourgeois, E.

    2009-08-01

    The paper highlights applications of some atmospheric pressure plasmas (dc-corona, streamer and spark and ac-Dielectric Barrier Discharges) to aerosol processes for Materials and Environment (filtration, diagnostics). The production of vapor i.e. condensable gaseous species, leads to nano-sized particles by physical and chemical routes of nucleation in these AP plasmas: (i) when dc streamer and spark filamentary discharges as well as ac filamentary dielectric barrier discharges interact with metal or dielectric surfaces, and (ii) when discharges induce reactions with gaseous precursors in volume. It is shown how composition, size and structure of primary nano-particles are related to plasma parameters (energy, number per unit surface and time and thermal gradients). Then the growth by coagulation controls the final size of agglomerates versus plasma parameters and transit time in and after the plasma. Charging and electro-thermal collection are depicted to account for the related potential applications of controlled kinematics of charged aerosol.

  11. Surface Modification by Atmospheric Pressure Plasma for Improved Bonding

    Science.gov (United States)

    Williams, Thomas Scott

    An atmospheric pressure plasma source operating at temperatures below 150?C and fed with 1.0-3.0 volume% oxygen in helium was used to activate the surfaces of the native oxide on silicon, carbon-fiber reinforced epoxy composite, stainless steel type 410, and aluminum alloy 2024. Helium and oxygen were passed through the plasma source, whereby ionization occurred and ˜10 16 cm-3 oxygen atoms, ˜1015 cm -3 ozone molecules and ˜1016 cm-3 metastable oxygen molecules (O21Deltag) were generated. The plasma afterglow was directed onto the substrate material located 4 mm downstream. Surface properties of the plasma treated materials have been investigated using water contact angle (WCA), atomic force microscopy (AFM), infrared spectroscopy (IR), and x-ray photoelectron spectroscopy (XPS). The work presented herein establishes atmospheric-pressure plasma as a surface preparation technique that is well suited for surface activation and enhanced adhesive bond strength in a variety of materials. Atmospheric plasma activation presents an environmentally friendly alternative to wet chemical and abrasive methods of surface preparation. Attenuated total internal reflection infrared spectroscopy was used to study the aging mechanism of the native oxide on silicon. During storage at ambient conditions, the water contact angle of a clean surface increased from composite, stainless steel type 410, and aluminum alloy 2024 was demonstrated with the atmospheric pressure helium-oxygen plasma. All surfaces studied were converted from a hydrophobic state with a water contact angle of 65° to 80° into a hydrophilic state with a water contact angle between 20° and 40° within 5 seconds of plasma exposure. X-ray photoelectron spectroscopy confirmed that the carbon atoms on the carbon-fiber/epoxy composite were oxidized, yielding 17 atom% carboxylic acid groups, 10% ketones or aldehydes and 9% alcohols. Analysis of stainless steel and aluminum by XPS illustrate oxidation of the metal

  12. Microwave heating systems for atmospheric pressure: Nonequilibrium plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Guest, G.E.; Dandl, R.A. (AMPC, Inc., Carlsbad, CA (USA))

    1989-03-01

    Nonequilibrium plasma-chemical processing is attracting increasing interest because of the possibility of creating mixtures of active species that would not be available in thermal equilibrium. For significant throughput of reactants it would be advantageous to create nonequilibrium plasmas in large volumes of atmospheric-pressure mixtures of gases. Techniques for accomplishing this are very limited at present. Here they describe a novel microwave approach to creating nonequilibrium plasmas in large volumes of atmospheric-pressure gases using pulses of microwave radiation with very high peak power that are focused by quasi-optical techniques at one or more points in the interior of the reaction chamber. A new type of microwave source, the Plasma Electron Microwave Source (PEMS), is able to produce the require power levels by storing cw microwave power in a mirror-confined, relativistic-electron plasma and periodically transforming a fraction of that stored energy into intense microwave pulses. This approach avoids many of the limitations inherent in resonant cavity approaches and is expected to permit ultrahigh purity discharges to be produced.

  13. Bacteria Inactivation Using DBD Plasma Jet in Atmospheric Pressure Argon

    Institute of Scientific and Technical Information of China (English)

    XU Guimin; ZHANG Guanjun; SHI Xingmin; MA Yue; WANG Ning; LI Yuan

    2009-01-01

    A coaxial dielectric barrier discharge plasma jet Was designed,which can be operated in atmospheric pressure argon under an intermediate frequency sinusoidal resonant power supply,and an atmospheric pressure glow-like discharge Was achieved.Two kinds of typical bacteria,i.e.,the Staphylococcus aureus(S.aurens)and Escherichia coil(E.coil),were employed to study the bacterial inactivation mechanism by means of the non-thermal plasma.The killing log value (KLV)of S.aureus reached up to 5.38 with a treatment time of 90 s and that of E.coil up to 5.36 with 60 s,respectively.According to the argon emission spectra of the plasma jet and the scanning electron microscope (SEM) images of the two bacteria before and after the plasma treatment.it is concluded that the reactive species in the argon plasma played a major role in the bacterial inactivation,while the heat,electric field and UV photons had little effect.

  14. Polymerization of acrylic acid using atmospheric pressure DBD plasma jet

    Science.gov (United States)

    Bashir, M.; Bashir, S.

    2016-08-01

    In this paper polymerization of acrylic acid was performed using non thermal atmospheric pressure plasma jet technology. The goal of this study is to deposit organic functional coatings for biomedical applications using a low cost and rapid growth rate plasma jet technique. The monomer solution of acrylic acid was vaporized and then fed into the argon plasma for coating. The discharge was powered using a laboratory made power supply operating with sinusoidal voltage signals at a frequency of 10 kHz. The optical emission spectra were collected in order to get insight into the plasma chemistry during deposition process. The coatings were characterized using Fourier transform infrared spectroscopy, atomic force microscopy and growth rates analysis. A high retention of carboxylic functional groups of the monomer was observed at the surface deposited using this low power technique.

  15. Diagnostics of atmospheric pressure capillary DBD oxygen plasma jet

    CERN Document Server

    Roy, N C; Pramanik, B K

    2015-01-01

    Atmospheric pressure capillary dielectric barrier oxygen discharge plasma jet is developed to generate non-thermal plasma using unipolar positive pulse power supply. Both optical and electrical techniques are used to investigate the characteristics of the produced plasma as function of applied voltage and gas flow rate. Analytical results obtained from the optical emission spectroscopic data reveal the gas temperature, rotational temperature, excitation temperature and electron density. Gas temperature and rotational temperature are found to decrease with increasing oxygen flow rate but increase linearly with applied voltage. It is exposed that the electron density is boosting up with enhanced applied voltage and oxygen flow rate, while the electron excitation temperature is reducing with rising oxygen flow rate. Electrical characterization demonstrates that the discharge frequency is falling with flow rate but increasing with voltage. The produced plasma is applied preliminarily to study the inactivation yie...

  16. On the mechanism of atmospheric pressure plasma plume

    Science.gov (United States)

    Chen, Longwei; Zhao, Peng; Shu, Xingsheng; Shen, Jie; Meng, Yuedong

    2010-08-01

    For the purpose of unveiling the parameters influencing the length of atmospheric pressure plasma plume, an over 165 cm long argon plasma plume is generated in the quartz tube attached to the nozzle of the device. Dependence of plasma length on discharge parameters such as applied voltage, frequency of power supply, and argon gas flow rate was investigated. Experimental results indicated that (a) the applied voltage plays crucial roles on plasma plume length, that is, the plasma plume length exponentially increases with the applied voltage, (b) the plasma plume length increases with frequency, more obviously when the applied voltage is higher, (c) the plasma plume length increases with argon gas flow rate, reaches its maximum at critical value of the gas flow rate, and then decreases again. An evaluation of the physical phenomena involved in streamer propagation, particularly of the energy balance, was investigated. The numerical results were qualitatively consistent with previous experimental results by successfully indicating the high velocity of "plasma bullet" and providing physical mechanism of energy balance determining streamer length.

  17. In situ impedance measurement of microwave atmospheric pressure plasma

    Science.gov (United States)

    Lee, S. T.; Nam, W. J.; Lee, J. K.; Yun, G. S.

    2017-04-01

    The impedance of atmospheric pressure argon plasma jets driven by microwave frequency is determined in situ by a novel ‘two frequency method’. In the conventional method of reflection coefficient ({{S}}11) measurement, the frequency of the driving microwave power is scanned, which inevitably affects the plasma characters and leads to uncertainty in the estimated plasma impedance. In our proposed method, the frequency-scanning signal additional to the driving power is used to measure {{S}}11 over a wide frequency range, which enables accurate determination of the plasma impedance based on an equivalent circuit model. The measured resistance and reactance of the plasma increase with the driving power in agreement with the transmission line theory. Based on this in situ measurement of the plasma impedance, the net power coupled to the plasma has been determined. The overall power efficiency remains approximately unchanged around 45% for different input power levels owing to the competing effects between the impedance mismatch and the volume change of the plasma.

  18. Novel applications of atmospheric pressure plasma on textile materials

    Science.gov (United States)

    Cornelius, Carrie Elizabeth

    Various applications of atmospheric pressure plasma are investigated in conjunction with polymeric materials including paper, polypropylene non-woven fabric, and cotton. The effect of plasma on bulk and surface properties is examined by treating both cellulosic pulp and prefabricated paper with various plasma-gas compositions. After treatment, pulp is processed into paper and the properties are compared. The method of pulp preparation is found to be more significant than the plasma, but differences in density, strength, and surface roughness are apparent for the pulp vs. paper plasma treatments. The plasma is also used to remove sizes of PVA and starch from poly/cotton and cotton fabric respectively. In both cases plasma successfully removes a significant amount of size, but complete size removal is not achieved. Subsequent washes (PVA) or scouring (cotton) to remove the size are less successful than a control, suggesting the plasma is crosslinking the size that is not etched away. However, at short durations in cold water using an oxygen plasma, slightly more PVA is removed than with a control. For the starch sized samples, plasma and scouring are never as successful at removing starch as a conventional enzyme, but plasma improves dyeability without need for scouring. Plasma is also used to graft chemicals to the surface of polypropylene and cotton fabric. HTCC, an antimicrobial is grafted to polypropylene with successful grafting indicated by x-ray photoemission spectroscopy (XPS), dye tests, and Fourier transform infrared spectroscopy (FTIR). Antimicrobial activity of the grafted samples is also characterized. 3ATAC, a vinyl monomer is also grafted to polypropylene and to cotton. Additives including Mohr's salt, potassium persulfate, and diacrylate are assessed to increase yield. Successful grafting of 3ATAC is confirmed by XPS and dye testing. A combination of all three additives is identified as optimum for maximizing graft yield.

  19. Application of atmospheric pressure plasma in polymer and composite adhesion

    Science.gov (United States)

    Yu, Hang

    An atmospheric pressure helium and oxygen plasma was used to investigate surface activation and bonding in polymer composites. This device was operated by passing 1.0-3.0 vol% of oxygen in helium through a pair of parallel plate metal electrodes powered by 13.56 or 27.12 MHz radio frequency power. The gases were partially ionized between the capacitors where plasma was generated. The reactive species in the plasma were carried downstream by the gas flow to treat the substrate surface. The temperature of the plasm gas reaching the surface of the substrate did not exceed 150 °C, which makes it suitable for polymer processing. The reactive species in the plasma downstream includes ~ 1016-1017 cm-3 atomic oxygen, ~ 1015 cm-3 ozone molecule, and ~ 10 16 cm-3 metastable oxygen molecule (O2 1Deltag). The substrates were treated at 2-5 mm distance from the exit of the plasma. Surface properties of the substrates were characterized using water contact angle (WCA), atomic force microscopy (AFM), infrared spectroscopy (IR), and X-ray photoelectron spectroscopy (XPS). Subsequently, the plasma treated samples were bonded adhesively or fabricated into composites. The increase in mechanical strength was correlated to changes in the material composition and structure after plasma treatment. The work presented hereafter establishes atmospheric pressure plasma as an effective method to activate and to clean the surfaces of polymers and composites for bonding. This application can be further expanded to the activation of carbon fibers for better fiber-resin interactions during the fabrication of composites. Treating electronic grade FR-4 and polyimide with the He/O2 plasma for a few seconds changed the substrate surface from hydrophobic to hydrophilic, which allowed complete wetting of the surface by epoxy in underfill applications. Characterization of the surface by X-ray photoelectron spectroscopy shows formation of oxygenated functional groups, including hydroxyl, carbonyl, and

  20. 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.

  1. Characteristics of Atmospheric Pressure Rotating Gliding Arc Plasmas

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hao; ZHU Fengsen; TU Xin; BO Zheng; CEN Kefa; LI Xiaodong

    2016-01-01

    In this work,a novel direct current (DC) atmospheric pressure rotating gliding arc (RGA) plasma reactor has been developed for plasma-assisted chemical reactions.The influence of the gas composition and the gas flow rate on the arc dynamic behaviour and the formation of reactive species in the N2 and air gliding arc plasmas has been investigated by means of electrical signals,high speed photography,and optical emission spectroscopic diagnostics.Compared to conventional gliding arc reactors with knife-shaped electrodes which generally require a high flow rate (e.g.,10-20 L/min) to maintain a long arc length and reasonable plasma discharge zone,in this RGA system,a lower gas flow rate (e.g.,2 L/min) can also generate a larger effective plasma reaction zone with a longer arc length for chemical reactions.Two different motion patterns can be clearly observed in the N2 and air RGA plasmas.The time-resolved arc voltage signals show that three different arc dynamic modes,the arc restrike mode,takeover mode,and combined modes,can be clearly identified in the RGA plasmas.The occurrence of different motion and arc dynamic modes is strongly dependent on the composition of the working gas and gas flow rate.

  2. Characteristics of Atmospheric Pressure Rotating Gliding Arc Plasmas

    Science.gov (United States)

    Zhang, Hao; Zhu, Fengsen; Tu, Xin; Bo, Zheng; Cen, Kefa; Li, Xiaodong

    2016-05-01

    In this work, a novel direct current (DC) atmospheric pressure rotating gliding arc (RGA) plasma reactor has been developed for plasma-assisted chemical reactions. The influence of the gas composition and the gas flow rate on the arc dynamic behaviour and the formation of reactive species in the N2 and air gliding arc plasmas has been investigated by means of electrical signals, high speed photography, and optical emission spectroscopic diagnostics. Compared to conventional gliding arc reactors with knife-shaped electrodes which generally require a high flow rate (e.g., 10-20 L/min) to maintain a long arc length and reasonable plasma discharge zone, in this RGA system, a lower gas flow rate (e.g., 2 L/min) can also generate a larger effective plasma reaction zone with a longer arc length for chemical reactions. Two different motion patterns can be clearly observed in the N2 and air RGA plasmas. The time-resolved arc voltage signals show that three different arc dynamic modes, the arc restrike mode, takeover mode, and combined modes, can be clearly identified in the RGA plasmas. The occurrence of different motion and arc dynamic modes is strongly dependent on the composition of the working gas and gas flow rate. supported by National Natural Science Foundation of China (No. 51576174), the Specialized Research Fund for the Doctoral Program of Higher Education of China (No. 20120101110099) and the Fundamental Research Funds for the Central Universities (No. 2015FZA4011)

  3. Atmospheric pressure plasma assisted calcination of composite submicron fibers

    Science.gov (United States)

    Medvecká, Veronika; Kováčik, Dušan; Tučeková, Zlata; Zahoranová, Anna; Černák, Mirko

    2016-08-01

    The plasma assisted calcination of composite organic/inorganic submicron fibers for the preparation of inorganic fibers in submicron scale was studied. Aluminium butoxide/polyvinylpyrrolidone fibers prepared by electrospinning were treated using low-temperature plasma generated by special type of dielectric barrier discharge, so called diffuse coplanar surface barrier discharge (DCSBD) at atmospheric pressure in ambient air, synthetic air, oxygen and nitrogen. Effect of plasma treatment on base polymer removal was investigated by using Attenuated total reflectance - Fourier transform infrared (ATR-FTIR) spectroscopy. Influence of working gas on the base polymer reduction was studied by energy-dispersive X-ray spectroscopy (EDX) and CHNS elemental analysis. Changes in fibers morphology were observed by scanning electron microscopy (SEM). High efficiency of organic template removal without any degradation of fibers was observed after plasma treatment in ambient air. Due to the low-temperature approach and short exposure time, the plasma assisted calcination is a promising alternative to the conventional thermal calcination. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  4. Sterilization of Surfaces with a Handheld Atmospheric Pressure Plasma

    Science.gov (United States)

    Hicks, Robert; Habib, Sara; Chan, Wai; Gonzalez, Eleazar; Tijerina, A.; Sloan, Mark

    2009-10-01

    Low temperature, atmospheric pressure plasmas have shown great promise for decontaminating the surfaces of materials and equipment. In this study, an atmospheric pressure, oxygen and argon plasma was investigated for the destruction of viruses, bacteria, and spores. The plasma was operated at an argon flow rate of 30 L/min, an oxygen flow rate of 20 mL/min, a power density of 101.0 W/cm^3 (beam area = 5.1 cm^2), and at a distance from the surface of 7.1 mm. An average 6log10 reduction of viable spores was obtained after only 45 seconds of exposure to the reactive gas. By contrast, it takes more than 35 minutes at 121^oC to sterilize anthrax in an autoclave. The plasma properties were investigated by numerical modeling and chemical titration with nitric oxide. The numerical model included a detailed reaction mechanism for the discharge as well as for the afterglow. It was predicted that at a delivered power density of 29.3 W/cm^3, 30 L/min argon, and 0.01 volume% O2, the plasma generated 1.9 x 10^14 cm-3 O atoms, 1.6 x 10^12 cm-3 ozone, 9.3 x 10^13 cm-3 O2(^1δg), and 2.9 x 10^12 cm-3 O2(^1σ^+g) at 1 cm downstream of the source. The O atom density measured by chemical titration with NO was 6.0 x 10^14 cm-3 at the same conditions. It is believe that the oxygen atoms and the O2(^1δg) metastables were responsible for killing the anthrax and other microorganisms.

  5. Non-thermal atmospheric pressure plasma jet and its application for polymer treatment

    OpenAIRE

    Sarani, Abdollah

    2010-01-01

    Non-thermal atmospheric pressure plasma jet is a suitable source for polymer treatment. The main characteristic of this plasma jet is the remote operation and its scalable dimension, thus, allowing local treatment of 3D surfaces. In this work an atmospheric pressure DBD plasma jet has been constructed and the application of the plasma jet for polymer treatment is investigated.

  6. Trends in surface engineering of biomaterials: atmospheric pressure plasma deposition of coatings for biomedical applications

    Science.gov (United States)

    da Ponte, G.; Sardella, E.; Fanelli, F.; D'Agostino, R.; Favia, P.

    2011-11-01

    Cold plasma processes for surface engineering of biomaterials and biomedical devices are traditionally performed at low pressure; more and more, though, surface modification plasma processes at atmospheric pressure are also gaining popularity. This short review is aimed to list briefly atmospheric pressure plasma processes reported, in the last decade, for adapting the surface of materials to the best interactions with cells, bacteria and biomolecules.

  7. Dynamics of apokamp-type atmospheric pressure plasma jets

    Science.gov (United States)

    Sosnin, Eduard A.; Panarin, Victor A.; Skakun, Victor S.; Baksht, Evgeny Kh.; Tarasenko, Victor F.

    2017-02-01

    The paper describes a new discharge source of atmospheric pressure plasma jets (APPJs) in air with no gas supply through the discharge region. In this discharge mode, plasma jets develop from the bending point of a bright current channel between two electrodes and are therefore termed an apokamp (from Greek `off' and `bend'). The apokamp can represent single plasma jets of length up 6 cm or several jets, and the temperature of such jets can range from more than 1000 °C at their base to 100-250 °C at their tip. Apokamps are formed at maximum applied voltage of positive polarity, provided that the second electrode is capacitively decoupled with ground. According to high-speed photography with time resolution from several nanoseconds to several tens of nanoseconds, the apokamp consists of a set of plasma bullets moving with a velocity of 100-220 km/s, which excludes the convective mechanism of plasma decay. Estimates on a 100-ns scale show that the near-electrode zones and the zones from which apokamps develop are close in temperature.

  8. Atmospheric pressure plasma enhanced spatial ALD of silver

    Energy Technology Data Exchange (ETDEWEB)

    Bruele, Fieke J. van den, E-mail: Fieke.vandenBruele@tno.nl; Smets, Mireille; Illiberi, Andrea; Poodt, Paul [Holst Centre/TNO, High Tech Campus 31, 5656 AE Eindhoven (Netherlands); Creyghton, Yves [TNO, High Tech Campus 21, 5656 AE Eindhoven (Netherlands); Buskens, Pascal [TNO, Rondom 1, 5612 AP Eindhoven, The Netherlands and DWI Leibniz-Institut für Interaktive Materialien, Aachen (Germany); Roozeboom, Fred [TNO, High Tech Campus 21, 5656 AE Eindhoven, The Netherlands and Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands)

    2015-01-15

    The authors have investigated the growth of thin silver films using a unique combination of atmospheric process elements: spatial atomic layer deposition and an atmospheric pressure surface dielectric barrier discharge plasma source. Silver films were grown on top of Si substrates with good purity as revealed by resistivity values as low as 18 μΩ cm and C- and F-levels below detection limits of energy dispersive x-ray analysis. The growth of the silver films starts through the nucleation of islands that subsequently coalesce. The authors show that the surface island morphology is dependent on surface diffusion, which can be controlled by temperature within the deposition temperature range of 100–120 °C.

  9. Plasma polymerization of acrylic acid onto polystyrene by cyclonic plasma at atmospheric pressure

    Science.gov (United States)

    Chang, Yi-Jan; Lin, Chin-Ho; Huang, Chun

    2016-01-01

    The cyclonic atmospheric-pressure plasma is developed for chamberless deposition of poly(acrylic acid) film from argon/acrylic acid mixtures. The photoemission plasma species in atmospheric-pressure plasma polymerization was identified by optical emission spectroscopy (OES). The OES diagnosis data and deposition results indicated that in glow discharge, the CH and C2 species resulted from low-energy electron-impact dissociation that creates deposition species, but the strong CO emission lines are related to nondeposition species. The acrylic acid flow rate is seen as the key factor affecting the film growth. The film surface analysis results indicate that a smooth, continuous, and uniform surface of poly(acrylic acid) films can be formed at a relatively low plasma power input. This study reveals the potential of chamberless film growth at atmospheric pressure for large-area deposition of poly(acrylic acid) films.

  10. Methane coupling in microwave plasma under atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    Changsheng Shen; Dekun Sun; Hongsheng Yang

    2011-01-01

    Methane coupling in microwave plasma under atmospheric pressure has been investigated.The effects of molar ratio n(CH4)/n(H2),flow rate and microwave power on the reaction have been studied.(1) With the decrease of n(CH4)/n(H2) ratio,methane conversion,C2 hydrocarbon yield,energy yield and space-time yield of acetylene increased,but the yield of carbon deposit decreased.(2) With the increase of microwave power,energy yield of acetylene decreased,but space-time yield of acetylene increased.(3) With the increase of flow rate,energy yield and space-time yield of acetylene increased first and then decreased.Finally,under the reaction conditions of CH4 flow rate of 700 mL/min,n(CH4)/n(H2) ratio of 1/4 and microwave power of 400 W,the energy yield and space-time yield of acetylene could reach 0.337 mmol/kJ and 12.3 mol/(s·m3),respectively.The reaction mechanism of methane coupling in microwave plasma has been investigated based on the thermodynamics of chemical reaction.Interestingly,the acetylene yield of methane coupling in microwave plasma was much higher than the maximum thermodynamic yield of acetylene.This phenomenon was tentatively explained from non-expansion work in the microwave plasma system.

  11. Power modulation in an atmospheric pressure plasma jet

    Science.gov (United States)

    Kelly, S.; Turner, M. M.

    2014-12-01

    Power modulation in an atmospheric pressure capacitively coupled radio frequency plasma jet is investigated by numerical modelling. The dynamics of successively pulsing the applied power on and off for a helium-oxygen (˜0.6%) plasma is investigated. The impact of power pulsing on reactive species generation and gas heating is discussed with control opportunities emphasized. Power modulation shows linear control for reactive species and heat flux delivery to a treatment surface above an initial phase of power growth. Power is found to be coupled primarily to the electrons with electron loss rates determining the interference between successive power modulation phases. Plasma decay in the power off phase is characterized by a large initial electron loss in the first 0.5 µs followed by ambipolar decay dominated by ions of opposite charge. Power modulation effects on gas heating show a larger range of temperature control when compared with convection cooling. Reactive oxygen species reaching a treatment surface are shown to typically vary over an order of magnitude for variation in the duty cycle.

  12. Destruction mechanisms for formaldehyde in atmospheric pressure low temperature plasmas

    Science.gov (United States)

    Storch, Daniel G.; Kushner, Mark J.

    1993-01-01

    Formaldehyde (CH2O) is a common pollutant of indoor air in residences and commercial buildings. The removal of CH2O from atmospheric pressure gas streams (N2/O2/H2O/CH2O) using plasmas generated by a dielectric barrier discharge has been theoretically investigated with the goal of cleansing indoor air. The model consists of a full accounting of the electron, ion, and neutral chemical kinetics in contaminated humid air. We find that the destruction of CH2O results dominantly from chemical attack by OH and O radicals, with the primary end products being CO and H2O. The predicted destruction rates for CH2O are typically 2-8 ppm/(mJ cm-3) (parts per million of CH2O in air/energy deposition). The elimination of the unwanted byproducts, CO and NO, using a platinum catalyst is discussed.

  13. Ultrafast laser-collision-induced fluorescence in atmospheric pressure plasma

    Science.gov (United States)

    Barnat, E. V.; Fierro, A.

    2017-04-01

    The implementation and demonstration of laser-collision-induced fluorescence (LCIF) generated in atmospheric pressure helium environments is presented in this communication. As collision times are observed to be fast (~10 ns), ultrashort pulse laser excitation (<100 fs) of the 23S to 33P (388.9 nm) is utilized to initiate the LCIF process. Both neutral-induced and electron-induced components of the LCIF are observed in the helium afterglow plasma as the reduced electric field (E/N) is tuned from  <0.1 Td to over 5 Td. Under the discharge conditions presented in this study (640 Torr He), the lower limit of electron density detection is ~1012 e cm‑3. The spatial profiles of the 23S helium metastable and electrons are presented as functions of E/N to demonstrate the spatial resolving capabilities of the LCIF method.

  14. Helium atmospheric pressure plasma jets touching dielectric and metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Norberg, Seth A., E-mail: norbergs@umich.edu; Johnsen, Eric, E-mail: ejohnsen@umich.edu [Department of Mechanical Engineering, University of Michigan, 2350 Hayward Street, Ann Arbor, Michigan 48109-2125 (United States); Kushner, Mark J., E-mail: mjkush@umich.edu [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, Michigan 48109-2122 (United States)

    2015-07-07

    Atmospheric pressure plasma jets (APPJs) are being investigated in the context plasma medicine and biotechnology applications, and surface functionalization. The composition of the surface being treated ranges from plastics, liquids, and biological tissue, to metals. The dielectric constant of these materials ranges from as low as 1.5 for plastics to near 80 for liquids, and essentially infinite for metals. The electrical properties of the surface are not independent variables as the permittivity of the material being treated has an effect on the dynamics of the incident APPJ. In this paper, results are discussed from a computational investigation of the interaction of an APPJ incident onto materials of varying permittivity, and their impact on the discharge dynamics of the plasma jet. The computer model used in this investigation solves Poisson's equation, transport equations for charged and neutral species, the electron energy equation, and the Navier-Stokes equations for the neutral gas flow. The APPJ is sustained in He/O{sub 2} = 99.8/0.2 flowing into humid air, and is directed onto dielectric surfaces in contact with ground with dielectric constants ranging from 2 to 80, and a grounded metal surface. Low values of relative permittivity encourage propagation of the electric field into the treated material and formation and propagation of a surface ionization wave. High values of relative permittivity promote the restrike of the ionization wave and the formation of a conduction channel between the plasma discharge and the treated surface. The distribution of space charge surrounding the APPJ is discussed.

  15. Plasma Disinfection and the Deterioration of Surgical Tools at Atmospheric Pressure Plasma

    Science.gov (United States)

    Zaaba, Siti Khadijah; Akitsu, Tetsuya; Ohkawa, Hiroshi; Katayama-Hirayama, Keiko; Tsuji, Masao; Shimizu, Naohiro; Imanishi, Yuichirou

    The purpose of this paper is to present and compare disinfection effect of plasma by means of Atmospheric Pressure Glow plasma and streamer discharge. Geobacillus stearothermophilus was used as biological indicator for disinfection process. The effect of blades after irradiated in plasma was also studied by SEM analysis. It was found that the disinfection process was effective when the cylindrical configuration was applied. Carbon steel blade was also found to be deteriorated after immersed in plasma irradiation. Results indicate that disinfection can be achieved and at the same time deteriorations of the tools were observed.

  16. Atmospheric Pressure Plasma Jet for Chem/Bio Warfare Decontamination

    Science.gov (United States)

    Herrmann, Hans W.; Henins, Ivars; Park, Jaeyoung; Selwyn, Gary S.

    1999-11-01

    Atmospheric Pressure Plasma Jet (APPJ) technology may provide a much needed method of CBW decontamination which, unlike traditional decon methods, is dry and nondestructive to sensitive equipment and materials. The APPJ discharge uses a high-flow feedgas consisting primarily of an inert carrier gas, such as He, and a small amount of a reactive additive, such as O2, which flows between capacitively-coupled electrodes powered at 13.56 MHz. The plasma generates highly reactive metastable and atomic species of oxygen which are then directed onto a contaminated surface. The reactive effluent of the APPJ has been shown to effectively neutralize VX nerve agent as well as simulants for anthrax and mustard blister agent. Research efforts are now being directed towards reducing He consumption and increasing the allowable stand-off distance. Recent results demonstrate that by replacing the O2 reactive additive with CO2, ozone formation is greatly reduced. This has the result of extending the lifetime of atomic oxygen by an order of magnitude or more. A recirculating APP Decon Chamber which combines heat, vacuum, forced convection and reactivity is currently being developed for enhanced decontamination of sensitive equipment. Several techniques are also being evaluated for use in an APP Decon Jet for decontamination of items which cannot be placed inside a chamber.

  17. Basic characteristics of an atmospheric pressure rf generated plasma jet

    Institute of Scientific and Technical Information of China (English)

    Wang Shou-Guo; Li Hai-Jiang; Ye Tian-Chun; Zhao Ling-Li

    2004-01-01

    A plasma jet has been developed which operates using radio frequency (rf) power and produces a stable homogeneous discharge at atmospheric pressure. Its discharge characteristics, especially the dependence of stable discharge operating range on the feed gas, were studied, and the electric parameters such as RMS current, RMS voltage and reflected power were obtained with different gas flows. These studies indicate that there is an optimum range of operation of the plasma jet for a filling with a gas mixture of He and O2. Two "failure" modes of the discharge are identified.One is a filamentary arc when the input power is raised above a critical level, another is that the discharge disappears gradually as the addition of O2 approaches 3.2%. Possible explanations for the two failure modes have been given. The current and voltage waveform measurements show that there is a clear phase shift between normal and failure modes.In addition, Ⅰ-Ⅴ curves as a function of pure helium and for 1% addition of oxygen have been studied.

  18. Adhesion improvement of fibres by continuous plasma treatment at atmospheric pressure

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Løgstrup Andersen, Tom; Sørensen, Bent F.

    2013-01-01

    Carbon fibres and ultra-high-molecular-weight polyethylene (UHMWPE) fibres were continuously treated by a dielectric barrier discharge plasma at atmospheric pressure for adhesion improvement with epoxy resins. The plasma treatment improved wettability, increased the oxygen containing polar...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-12-15

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

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

    Science.gov (United States)

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

    2015-12-01

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

  1. Polymer Surface Treatment by Atmospheric Pressure Low Temperature Surface Discharge Plasma:Its Characteristics and Comparison with Low Pressure Oxygen Plasma Treatment

    Institute of Scientific and Technical Information of China (English)

    Atsushi KUWABARA; Shin-ichi KURODA; Hitoshi KUBOTA

    2007-01-01

    The polymer treatment with a low-temperature plasma jet generated on the atmospheric pressure surface discharge (SD) plasma is performed.The change of the surface property over time,in comparison with low pressure oxygen (O2) plasma treatment,is examined.As one compares the treatment by atmospheric pressure plasma to that by the low pressure O2 plasma of PS (polystyrene) the treatment effects were almost in complete agreement.However,when the atmospheric pressure plasma was used for PP(polypropylene),it produced remarkable hydrophilic effects.

  2. Modified drug release using atmospheric pressure plasma deposited siloxane coatings

    Science.gov (United States)

    Dowling, D. P.; Maher, S.; Law, V. J.; Ardhaoui, M.; Stallard, C.; Keenan, A.

    2016-09-01

    This pilot study evaluates the potential of atmospheric plasma polymerised coatings to modify the rate of drug release from polymeric substrates. The antibiotic rifampicin was deposited in a prototype multi-layer drug delivery system, consisting of a nebulized layer of active drug between a base layer of TEOS deposited on a plastic substrate (polystyrene) and an overlying layer of plasma polymerised PDMS. The polymerised TEOS and PDMS layers were deposited using a helium atmospheric plasma jet system. Elution of rifampicin was measured using UV-VIS spectroscopy, in addition to a antimicrobial well diffusion assay with an established indicator organism. The multi-layered plasma deposited coatings significantly extended the duration of release of the rifampicin from 24 h for the uncoated polymer to 144 h for the coated polymer.

  3. Atmospheric-pressure plasma activation and surface characterization on polyethylene membrane separator

    Science.gov (United States)

    Tseng, Yu-Chien; Li, Hsiao-Ling; Huang, Chun

    2017-01-01

    The surface hydrophilic activation of a polyethylene membrane separator was achieved using an atmospheric-pressure plasma jet. The surface of the atmospheric-pressure-plasma-treated membrane separator was found to be highly hydrophilic realized by adjusting the plasma power input. The variations in membrane separator chemical structure were confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Chemical analysis showed newly formed carbonyl-containing groups and high surface concentrations of oxygen-containing species on the atmospheric-pressure-plasma-treated polymeric separator surface. It also showed that surface hydrophilicity primarily increased from the polar component after atmospheric-pressure plasma treatment. The surface and pore structures of the polyethylene membrane separator were examined by scanning electron microscopy, revealing a slight alteration in the pore structure. As a result of the incorporation of polar functionalities by atmospheric-pressure plasma activation, the electrolyte uptake and electrochemical impedance of the atmospheric-pressure-plasma-treated membrane separator improved. The investigational results show that the separator surface can be controlled by atmospheric-pressure plasma surface treatment to tailor the hydrophilicity and enhance the electrochemical performance of lithium ion batteries.

  4. 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.

  5. Selective cytotoxicity of indirect nonequilibrium atmospheric pressure plasma against ovarian clear-cell carcinoma.

    Science.gov (United States)

    Utsumi, Fumi; Kajiyama, Hiroaki; Nakamura, Kae; Tanaka, Hiromasa; Hori, Masaru; Kikkawa, Fumitaka

    2014-01-01

    Ovarian clear cell carcinoma (CCC) is a histological type of epithelial ovarian cancer that is less responsive to chemotherapy and associated with a poorer prognosis than serous and endometrioid carcinoma. Non-thermal atmospheric pressure plasma which produces reactive species has recently led to an explosion of research in plasma medicine. Plasma treatment can be applied to cancer treatment to induce apoptosis and tumor growth arrest. Furthermore, recent studies have shown that a medium exposed to plasma also has an anti-proliferative effect against cancer in the absence of direct exposure to plasma. In this study, we confirmed whether this indirect plasma has an anti-tumor effect against CCC, and investigated whether this efficacy is selective for cancer cells. Non-thermal atmospheric pressure plasma induced apoptosis in CCC cells, while human peritoneal mesothelial cells remained viable. Non-thermal atmospheric pressure plasma exhibits selective cytotoxicity against CCC cells which are resistant to chemotherapy.

  6. Atmospheric pressure plasma treatment of glassy carbon for adhesion improvement

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Mortensen, Henrik Junge; Stenum, Bjarne

    2007-01-01

    Glassy carbon plates were treated with an atmospheric pressure dielectric barrier discharge (DBD). He gas, gas mixtures of He and reactive gases such as O2, CO2 and NH3, Ar gas and Ar/NH3 gas mixture were used as treatment gases. The oxygen and nitrogen contents on the surface as well as defect...

  7. Correlation between helium atmospheric pressure plasma jet (APPJ) variables and plasma induced DNA damage

    Science.gov (United States)

    Adhikari, Ek R.; Ptasinska, Sylwia

    2016-09-01

    A helium atmospheric pressure plasma jet (APPJ) source with a dielectric capillary and two tubular electrodes was used to induce damage in aqueous plasmid DNA. The fraction of different types of DNA damage (i.e., intact or undamaged, double strand breaks (DSBs), and single strand breaks (SSBs)) that occurred as the result of plasma irradiation was quantified through analysis of agarose gel electrophoresis images. The total DNA damage increased with an increase in both flow rate and duration of irradiation, but decreased with an increase in distance between the APPJ and sample. The average power of the plasma was calculated and the length of APPJ was measured for various flow rates and voltages applied. The possible effects of plasma power and reactive species on DNA damage are discussed.

  8. 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).

  9. Atmospheric Pressure Low Temperature Plasma System for Additive Manufacturing

    Science.gov (United States)

    Burnette, Matthew; Staack, David

    2016-09-01

    There is growing interest in using plasmas for additive manufacturing, however these methods use high temperature plasmas to melt the material. We have developed a novel technique of additive manufacturing using a low temperature dielectric barrier discharge (DBD) jet. The jet is attached to the head of a 3D printer to allow for precise control of the plasma's location. Various methods are employed to deposit the material, including using a vaporized precursor or depositing a liquid precursor directly onto the substrate or into the plasma via a nebulizer. Various materials can be deposited including metals (copper using copper (II) acetylacetonate), polymers (PMMA using the liquid monomer), and various hydrocarbon compounds (using alcohols or a 100% methane DBD jet). The rastering pattern for the 3D printer was modified for plasma deposition, since it was originally designed for thermoplastic extrusion. The design constraints for fill pattern selection for the plasma printer are influenced by substrate heating, deposition area, and precursor consumption. Depositions onto pressure and/or temperature sensitive substrates can be easily achieved. Deposition rates range up to 0.08 cm3/hr using tris(2-methoxyethoxy)(vinyl)silane, however optimization can still be done on the system to improve the deposition rate. For example higher concentration of precursor can be combined with faster motion and higher discharge powers to increase the deposition rate without overheating the substrate.

  10. Experimental characterization of an argon laminar plasma jet at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Langlois-Bertrand, Emilie; De Izarra, Charles, E-mail: charles.de_izarra@univ-orleans.fr [Groupe de Recherche sur l' Energetique des Milieux Ionises, UMR6606 Universite d' Orleans - CNRS, Faculte des Sciences, Site de Bourges, rue Gaston Berger, BP 4043, 18028 BOURGES Cedex (France)

    2011-10-19

    This paper deals with a dc laminar pure argon plasma jet operating at atmospheric pressure in ambient air that was experimentally studied in order to obtain temperature and velocity. Plasma jet temperature was evaluated by optical emission spectroscopy and the plasma jet velocity was determined by various methods using a pressure sensor. It is shown that the maximum plasma jet temperature is 15 000 K and the maximum plasma jet velocity is 250 m s{sup -1} at the plasma jet centre. Finally, a study of the ambient air amount entrained into the plasma jet is presented.

  11. Atmospheric pressure plasma surface modification of titanium for high temperature adhesive bonding

    NARCIS (Netherlands)

    Akram, M.; Jansen, K.M.B.; Ernst, L.J.; Bhowmik, S.

    2011-01-01

    In this investigation surface treatment of titanium is carried out by plasma ion implantation under atmospheric pressure plasma in order to increase the adhesive bond strength. Prior to the plasma treatment, titanium surfaces were mechanically treated by sand blasting. It is observed that the contac

  12. Diagnostics of Atmospheric Pressure Surface Discharge Plasmas in Argon

    Institute of Scientific and Technical Information of China (English)

    张锐; 詹如娟; 温晓辉

    2003-01-01

    Atmospheric pressure surface discharge is shown to have great prospects for a number of industrial applications.To acquire better results in application fields and considering that the study of the basic parameters including electron temperature and electron density is desirable,we develop an equivalent circuit model and the diagnostic techniques based on optical emission spectroscopy and electrical measurement in our laboratory.The electron temperature has been determined to be about 0.7eV by a Fermi-Dirac model.The electron density has been calculated to be near 1010 cm-3 from a time resolved electrical measurement(Ohmic heating method).

  13. Optical Emission Spectroscopy of an Atmospheric Pressure Plasma Jet During Tooth Bleaching Gel Treatment.

    Science.gov (United States)

    Šantak, Vedran; Zaplotnik, Rok; Tarle, Zrinka; Milošević, Slobodan

    2015-11-01

    Optical emission spectroscopy was performed during atmospheric pressure plasma needle helium jet treatment of various tooth-bleaching gels. When the gel sample was inserted under the plasma plume, the intensity of all the spectral features increased approximately two times near the plasma needle tip and up to two orders of magnitude near the sample surface. The color change of the hydroxylapatite pastille treated with bleaching gels in conjunction with the atmospheric pressure plasma jet was found to be in correlation with the intensity of OH emission band (309 nm). Using argon as an additive to helium flow (2 L/min), a linear increase (up to four times) of OH intensity and, consequently, whitening (up to 10%) of the pastilles was achieved. An atmospheric pressure plasma jet activates bleaching gel, accelerates OH production, and accelerates tooth bleaching (up to six times faster).

  14. Effect of microwave frequency on plasma formation in air breakdown at atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    赵朋程; 郭立新; 李慧敏

    2015-01-01

    Microwave breakdown at atmospheric pressure causes the formation of a discrete plasma structure. The one-dimensional fluid model coupling Maxwell equations with plasma fluid equations is used to study the effect of the mi-crowave frequency on the formation of air plasma. Simulation results show that, the filamentary plasma array propagating toward the microwave source is formed at different microwave frequencies. As the microwave frequency decreases, the ratio of the distance between two adjacent plasma filaments to the corresponding wavelength remains almost unchanged (on the order of 1/4), while the plasma front propagates more slowly due to the increase in the formation time of the new plasma filament.

  15. Properties of Atmospheric Pressure Ar Plasma Jet Depending on Treated Dielectric Material

    Science.gov (United States)

    Prysiazhnyi, Vadym; Ricci Castro, Alonso H.; Kostov, Konstantin G.

    2017-02-01

    Atmospheric pressure plasma jet operated in argon was utilized to modify surfaces of glass, acrylic, and PTFE dielectrics. This paper describes the influence of the dielectric substrate on operation and properties of plasma. Two modes of operation (each of those have two patterns) were described. The transition from one mode to another, values of the dissipated power, and spreading of plasma over the dielectric surfaces strongly depended on the substrate material. Additionally, three methods of plasma spreading estimation were presented and discussed.

  16. Non-thermal atmospheric pressure plasma activates lactate in Ringer's solution for anti-tumor effects.

    Science.gov (United States)

    Tanaka, Hiromasa; Nakamura, Kae; Mizuno, Masaaki; Ishikawa, Kenji; Takeda, Keigo; Kajiyama, Hiroaki; Utsumi, Fumi; Kikkawa, Fumitaka; Hori, Masaru

    2016-11-08

    Non-thermal atmospheric pressure plasma is a novel approach for wound healing, blood coagulation, and cancer therapy. A recent discovery in the field of plasma medicine is that non-thermal atmospheric pressure plasma not only directly but also indirectly affects cells via plasma-treated liquids. This discovery has led to the use of non-thermal atmospheric pressure plasma as a novel chemotherapy. We refer to these plasma-treated liquids as plasma-activated liquids. We chose Ringer's solutions to produce plasma-activated liquids for clinical applications. In vitro and in vivo experiments demonstrated that plasma-activated Ringer's lactate solution has anti-tumor effects, but of the four components in Ringer's lactate solution, only lactate exhibited anti-tumor effects through activation by non-thermal plasma. Nuclear magnetic resonance analyses indicate that plasma irradiation generates acetyl and pyruvic acid-like groups in Ringer's lactate solution. Overall, these results suggest that plasma-activated Ringer's lactate solution is promising for chemotherapy.

  17. Intracellular effects of atmospheric-pressure plasmas on melanoma cancer cells

    Science.gov (United States)

    Ishaq, M.; Bazaka, K.; Ostrikov, K.

    2015-12-01

    Gas discharge plasmas formed at atmospheric pressure and near room temperature have recently been shown as a promising tool for cancer treatment. The mechanism of the plasma action is attributed to generation of reactive oxygen and nitrogen species, electric fields, charges, and photons. The relative importance of different modes of action of atmospheric-pressure plasmas depends on the process parameters and specific treatment objects. Hence, an in-depth understanding of biological mechanisms that underpin plasma-induced death in cancer cells is required to optimise plasma processing conditions. Here, the intracellular factors involved in the observed anti-cancer activity in melanoma Mel007 cells are studied, focusing on the effect of the plasma treatment dose on the expression of tumour suppressor protein TP73. Over-expression of TP73 causes cell growth arrest and/or apoptosis, and hence can potentially be targeted to enhance killing efficacy and selectivity of the plasma treatment. It is shown that the plasma treatment induces dose-dependent up-regulation of TP73 gene expression, resulting in significantly elevated levels of TP73 RNA and protein in plasma-treated melanoma cells. Silencing of TP73 expression by means of RNA interference inhibited the anticancer effects of the plasma, similar to the effect of caspase inhibitor z-VAD or ROS scavenger N-acetyl cysteine. These results confirm the role of TP73 protein in dose-dependent regulation of anticancer activity of atmospheric-pressure plasmas.

  18. Intracellular effects of atmospheric-pressure plasmas on melanoma cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Ishaq, M., E-mail: ishaqmusarat@gmail.com [Peter MacCallum Cancer Centre, East Melbourne, VIC 3002 (Australia); Comonwealth Scientific and Industrial Research Organization, Sydney, New South Wales (Australia); Bazaka, K. [Institute for Health and Biomedical Innovation, School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4000 (Australia); Ostrikov, K. [Comonwealth Scientific and Industrial Research Organization, Sydney, New South Wales (Australia); Institute for Health and Biomedical Innovation, School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4000 (Australia)

    2015-12-15

    Gas discharge plasmas formed at atmospheric pressure and near room temperature have recently been shown as a promising tool for cancer treatment. The mechanism of the plasma action is attributed to generation of reactive oxygen and nitrogen species, electric fields, charges, and photons. The relative importance of different modes of action of atmospheric-pressure plasmas depends on the process parameters and specific treatment objects. Hence, an in-depth understanding of biological mechanisms that underpin plasma-induced death in cancer cells is required to optimise plasma processing conditions. Here, the intracellular factors involved in the observed anti-cancer activity in melanoma Mel007 cells are studied, focusing on the effect of the plasma treatment dose on the expression of tumour suppressor protein TP73. Over-expression of TP73 causes cell growth arrest and/or apoptosis, and hence can potentially be targeted to enhance killing efficacy and selectivity of the plasma treatment. It is shown that the plasma treatment induces dose-dependent up-regulation of TP73 gene expression, resulting in significantly elevated levels of TP73 RNA and protein in plasma-treated melanoma cells. Silencing of TP73 expression by means of RNA interference inhibited the anticancer effects of the plasma, similar to the effect of caspase inhibitor z-VAD or ROS scavenger N-acetyl cysteine. These results confirm the role of TP73 protein in dose-dependent regulation of anticancer activity of atmospheric-pressure plasmas.

  19. Cold atmospheric pressure plasma treatment of ready-to-eat meat

    DEFF Research Database (Denmark)

    Röd, Sara Katrine Solhøj; Hansen, Flemming; Leipold, Frank

    Sliced ready-to-eat (RTE) meat products are susceptible to growth of the foodborne pathogenic bacterium, Listeria monocytogenes. Cold atmospheric pressure plasma (CAPP) may be applicable for surface decontamination in sealed bags thus avoiding recontamination. Plasmas (Fig. 1), created in neutral...

  20. DNA strand scission induced by a non-thermal atmospheric pressure plasma jet.

    Science.gov (United States)

    Ptasińska, Sylwia; Bahnev, Blagovest; Stypczyńska, Agnieszka; Bowden, Mark; Mason, Nigel J; Braithwaite, Nicholas St J

    2010-07-28

    The DNA molecule is observed to be very susceptible to short-term exposures to an atmospheric pressure plasma jet. The DNA damage induced by plasma-generated species, i.e. excited atoms, charged particles, electrons and UV light is determined.

  1. Decontamination of objects in a sealed container by means of atmospheric pressure plasmas

    DEFF Research Database (Denmark)

    Leipold, Frank; Schultz-Jensen, Nadja; Kusano, Yukihiro

    2011-01-01

    The decontamination of objects (food) in a sealed container by means of atmospheric pressure plasmas is investigated. The target is Listeria monocytogenes, a bacterium which causes listeriosis and can be found in plants and food. The non-pathogenic species, Listeria innocua, is used....... The ambient atmosphere was air at atmospheric pressure. A plasma is generated inside the bag forming ozone from the oxygen. The maximum ozone concentration in the bag was found to be 140 ppm. A log 6 reduction of L. innocua is obtained after 15 min of exposure time. The temperature of the slides after...

  2. 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

  3. Characterization of a Dielectric Barrier Plasma Gun Discharging at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guang-Qiu; GE Yuan-Jing; ZHANG Yue-Fei; CHEN Guang-Liang

    2004-01-01

    @@ We develop a plasma gun based on dielectric barrier discharge and working at atmospheric pressure. A theoretical model to predict the gun discharge voltage is built, which is in agreement with the experimental results. After investigating the characterization of discharging gun and utilizing it for polymerization, we find that the gun can be used as a source to generate a stable uniform plasma for different plasma-processing technologies.

  4. Spectroscopic characterization of atmospheric pressure um-jet plasma source

    CERN Document Server

    Bibinov, Nikita; Bahre, Hendrik; Awakowicz, Peter; der Gathen, Volker Schulz-von

    2011-01-01

    A radio frequency um-jet plasma source is studied using He/O2 mixture. This um-jet can be used for different applications as a source of chemical active species e.g. oxygen atoms, molecular metastables and ozone. Using absolutely-calibrated optical emission spectroscopy and numerical simulation, the gas temperature in active plasma region and plasma parameters (electron density and electron distribution function) are determined. Concentrations of oxygen atoms and ozone in the plasma channel and in the effluent of the plasma source are measured using emission and absorption spectroscopy. To interpret the measured spatial distributions, the steady-state species' concentrations are calculated using determined plasma parameters and gas temperature. At that the influence of the surface processes and gas flow regime on the loss of the active species in the plasma source are discussed. The measured spatial distributions of oxygen atom and ozone densities are compared with the simulated ones.

  5. A Novel Atmospheric Pressure Plasma Fluidized Bed and Its Application in Mutation of Plant Seeds

    Institute of Scientific and Technical Information of China (English)

    CHEN Guang-Liang; WANG Zhen-Quan; HAN Er-Li; FU Ya-Bo; YANG Si-Ze; FAN Song-Hua; LI Chun-Ling; GU Wei-Chao; FENG Wen-Ran; ZHANG Gu-Ling; WANG Jiu-Li; Latif K.; ZHANG Shu-Gen

    2005-01-01

    @@ An atmospheric pressure plasma fluidized bed (APPFB) is designed to generate plasma using a dielectric barrier discharge (DBD) with one liquid electrode. In the APPFB system, the physical properties of DBD discharge and its application in plant-seed mutating are studied fundamentally. The results show that the generated plasma is a typical glow discharge free from filament and arc plasma, and the macro-temperature of the plasma fluidized bed is nearly at room temperature. There are no obvious changes in the pimientos when their seeds are treated by APPFB, but great changes are found for coxcombs.

  6. Theoretical Computation for Non-Equilibrium Air Plasma Electrical Conductivity at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    HAN Dong; GUO Wen-Kang; XU Ping; LIANG Rong-Qing

    2007-01-01

    @@ Based on the Chapman-Enskog theory, we calculate the electrical conductivity of non-equilibrium air plasma in the two-temperature model. We consider different degrees of non-equilibrium, which is defined by the ratio of electronic temperature to heavy particles temperature. The method of computing the composition of air plasma is demonstrated. After calculating the electrical conductivity from electron temperature 1000 K to 15000K, the present result is compared with Murphy's study [Plasma Chem. Plasma Process 15 (1994) 279] for equilibrium case. All the calculation is completed at atmospheric pressure. The present results may have potential applications in numerical calculation of non-equilibrium air plasma.

  7. Reactive species in non-equilibrium atmospheric-pressure plasmas: Generation, transport, and biological effects

    Energy Technology Data Exchange (ETDEWEB)

    Lu, X., E-mail: luxinpei@hotmail.com [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Naidis, G.V. [Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Laroussi, M. [Plasma Engineering & Medicine Institute, Old Dominion University, Norfolk, VA 23529 (United States); Reuter, S. [Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff-Strasse 2, 17489 Greifswald (Germany); Graves, D.B. [Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720 (United States); Ostrikov, K. [Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000 (Australia); School of Physics, Chemistry, and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4000 (Australia); Commonwealth Scientific and Industrial Research Organization, P.O.Box 218, Lindfield, NSW 2070 (Australia); School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia)

    2016-05-04

    Non-equilibrium atmospheric-pressure plasmas have recently become a topical area of research owing to their diverse applications in health care and medicine, environmental remediation and pollution control, materials processing, electrochemistry, nanotechnology and other fields. This review focuses on the reactive electrons and ionic, atomic, molecular, and radical species that are produced in these plasmas and then transported from the point of generation to the point of interaction with the material, medium, living cells or tissues being processed. The most important mechanisms of generation and transport of the key species in the plasmas of atmospheric-pressure plasma jets and other non-equilibrium atmospheric-pressure plasmas are introduced and examined from the viewpoint of their applications in plasma hygiene and medicine and other relevant fields. Sophisticated high-precision, time-resolved plasma diagnostics approaches and techniques are presented and their applications to monitor the reactive species and plasma dynamics in the plasma jets and other discharges, both in the gas phase and during the plasma interaction with liquid media, are critically reviewed. The large amount of experimental data is supported by the theoretical models of reactive species generation and transport in the plasmas, surrounding gaseous environments, and plasma interaction with liquid media. These models are presented and their limitations are discussed. Special attention is paid to biological effects of the plasma-generated reactive oxygen and nitrogen (and some other) species in basic biological processes such as cell metabolism, proliferation, survival, etc. as well as plasma applications in bacterial inactivation, wound healing, cancer treatment and some others. Challenges and opportunities for theoretical and experimental research are discussed and the authors’ vision for the emerging convergence trends across several disciplines and application domains is presented to

  8. Reactive species in non-equilibrium atmospheric-pressure plasmas: Generation, transport, and biological effects

    Science.gov (United States)

    Lu, X.; Naidis, G. V.; Laroussi, M.; Reuter, S.; Graves, D. B.; Ostrikov, K.

    2016-05-01

    Non-equilibrium atmospheric-pressure plasmas have recently become a topical area of research owing to their diverse applications in health care and medicine, environmental remediation and pollution control, materials processing, electrochemistry, nanotechnology and other fields. This review focuses on the reactive electrons and ionic, atomic, molecular, and radical species that are produced in these plasmas and then transported from the point of generation to the point of interaction with the material, medium, living cells or tissues being processed. The most important mechanisms of generation and transport of the key species in the plasmas of atmospheric-pressure plasma jets and other non-equilibrium atmospheric-pressure plasmas are introduced and examined from the viewpoint of their applications in plasma hygiene and medicine and other relevant fields. Sophisticated high-precision, time-resolved plasma diagnostics approaches and techniques are presented and their applications to monitor the reactive species and plasma dynamics in the plasma jets and other discharges, both in the gas phase and during the plasma interaction with liquid media, are critically reviewed. The large amount of experimental data is supported by the theoretical models of reactive species generation and transport in the plasmas, surrounding gaseous environments, and plasma interaction with liquid media. These models are presented and their limitations are discussed. Special attention is paid to biological effects of the plasma-generated reactive oxygen and nitrogen (and some other) species in basic biological processes such as cell metabolism, proliferation, survival, etc. as well as plasma applications in bacterial inactivation, wound healing, cancer treatment and some others. Challenges and opportunities for theoretical and experimental research are discussed and the authors' vision for the emerging convergence trends across several disciplines and application domains is presented to

  9. Cold plasma source for bacterial inactivation at atmospheric pressure

    DEFF Research Database (Denmark)

    Chen, Weifeng; Stamate, Eugen; Mejlholm, Ole

    A dielectric-barrier discharge system for cold plasma production was built for bacterial inactivation purpose. The eect of cold plasma treatment on sensory properties of seafood products was studied to establish how the sensory properties (e.g. appearance, texture) of seafood were aected by diere...

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

    Science.gov (United States)

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

    2014-11-01

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

  11. Spectral Measurement of Atmospheric Pressure Plasma by Means of Digital Camera

    Institute of Scientific and Technical Information of China (English)

    葛袁静; 张广秋; 刘益民; 赵志发

    2002-01-01

    A digital camera measuring system has been used successfully to measure the space fluctuation behaviors of Induced Dielectric Barrier Discharge (IDBD) plasma at atmospheric pressure. The experimental results showed that: (1) The uniformity of electron temperature in space depends on discharge condition and structure of web electrode. For a certain web electrode the higher the discharge voltage is, the more uniform distribution of electron temperature in space will be. For a certain discharge the finer and denser the holes on web electrode are, the more uniform distribution of electron temperature in space will be (2). Digital camera is an available equipment to measure some behaviors of the plasma working at atmospheric pressure.

  12. Plasma chemistry in an atmospheric pressure Ar/NH3 dielectric barrier discharge

    DEFF Research Database (Denmark)

    Fateev, A.; Leipold, F.; Kusano, Y.

    2005-01-01

    An atmospheric pressure dielectric barrier discharge (DBD) in Ar/NH3 (0.1 - 10%) mixtures with a parallel plate electrode geometry was studied. The plasma was investigated by emission and absorption spectroscopy in the UV spectral range. Discharge current and voltage were measured as well. UV...... of an atmospheric pressure Ar/NH3 DBD are H-2, N-2 and N2H4. The hydrazine (N2H4) concentration in the plasma and in the exhaust gases at various ammonia concentrations and different discharge powers was measured. Thermal N2H4 decomposition into NH2 radicals may be used for NOx reduction processes....

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

    Science.gov (United States)

    Yu, Shuang; Wang, Kaile; Zuo, Shasha; Liu, Jiahui; Zhang, Jue; Fang, Jing

    2015-10-01

    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.

  14. 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.

  15. 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

    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...

  16. Atmospheric pressure plasma jet with high-voltage power supply based on piezoelectric transformer.

    Science.gov (United States)

    Babij, Michał; Kowalski, Zbigniew W; Nitsch, Karol; Silberring, Jerzy; Gotszalk, Teodor

    2014-05-01

    The dielectric barrier discharge plasma jet, an example of the nonthermal atmospheric pressure plasma jet (APPJ), generates low-temperature plasmas that are suitable for the atomization of volatile species and can also be served as an ionization source for ambient mass and ion mobility spectrometry. A new design of APPJ for mass spectrometry has been built in our group. In these plasma sources magnetic transformers (MTs) and inductors are typically used in power supplies but they present several drawbacks that are even more evident when dealing with high-voltage normally used in APPJs. To overcome these disadvantages, high frequency generators with the absence of MT are proposed in the literature. However, in the case of miniaturized APPJs these conventional power converters, built of ferromagnetic cores and inductors or by means of LC resonant tank circuits, are not so useful as piezoelectric transformer (PT) based power converters due to bulky components and small efficiency. We made and examined a novel atmospheric pressure plasma jet with PT supplier served as ionization source for ambient mass spectrometry, and especially mobile spectrometry where miniaturization, integration of components, and clean plasma are required. The objective of this paper is to describe the concept, design, and implementation of this miniaturized piezoelectric transformer-based atmospheric pressure plasma jet.

  17. Bullet-to-streamer transition on the liquid surface of a plasma jet in atmospheric pressure

    Science.gov (United States)

    Yoon, S.-Y.; Kim, G.-H.; Kim, S.-J.; Bae, B.; Kim, N.-K.; Lee, H.; Bae, N.; Ryu, S.; Yoo, S. J.; Kim, S. B.

    2017-01-01

    This study investigated the transition of the plasma shape from a ring-shaped bullet to a pin-like streamer adjacent to the electrolyte surface in a kHz-driven helium atmospheric pressure plasma jet. The transition was observed by synchronized fast images, plasma propagation speed, time-resolved emission profile of Hβ, and spatially and temporally resolved helium metastable density. The transition height increased when electrolyte evaporation was enhanced. The plasma continued to discharge on the electrolyte surface even in the absence of metastable species, i.e., the discharge mechanism changed from Penning ionization between helium metastable and ambient nitrogen to electron collision on evaporated water.

  18. Eradication of Bacterial Biofilms Using Atmospheric Pressure Non-Thermal Plasmas

    Science.gov (United States)

    Alkawareek, Mahmoud; Gilmore, Brendan; Gorman, Sean; Algwari, Qais; Graham, William; O'Connell, Deborah

    2011-10-01

    Bacterial biofilms are ubiquitous in natural and clinical settings and form a major health risk. Biofilms are recognised to be the predominant mode of bacterial growth, and are an immunological challenge compared to planktonic bacteria of the same species. Eradication of biofilms with atmospheric pressure plasma jets is investigated. Cold non-equilibrium plasmas, operated at ambient atmospheric pressure and temperature, are efficient sources for controlled energy transport through highly reactive neutrals (e.g. ROS, RNS), charged particles (ions and electrons), UV radiation, and electro-magnetic fields. A focused panel of clinically significant biofilms, including Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Bacillus cereus, are exposed to various plasma jet configurations operated in helium and oxygen mixtures. Viability of surviving cells was determined using both standard plate counting method and XTT viability assay. These are correlated with measurements and simulations of relevant reactive plasma species.

  19. An Atmospheric Pressure Plasma Setup to Investigate the Reactive Species Formation.

    Science.gov (United States)

    Gorbanev, Yury; Soriano, Robert; O'Connell, Deborah; Chechik, Victor

    2016-11-03

    Non-thermal atmospheric pressure ('cold') plasmas have received increased attention in recent years due to their significant biomedical potential. The reactions of cold plasma with the surrounding atmosphere yield a variety of reactive species, which can define its effectiveness. While efficient development of cold plasma therapy requires kinetic models, model benchmarking needs empirical data. Experimental studies of the source of reactive species detected in aqueous solutions exposed to plasma are still scarce. Biomedical plasma is often operated with He or Ar feed gas, and a specific interest lies in investigation of the reactive species generated by plasma with various gas admixtures (O2, N2, air, H2O vapor, etc.) Such investigations are very complex due to difficulties in controlling the ambient atmosphere in contact with the plasma effluent. In this work, we addressed common issues of 'high' voltage kHz frequency driven plasma jet experimental studies. A reactor was developed allowing the exclusion of ambient atmosphere from the plasma-liquid system. The system thus comprised the feed gas with admixtures and the components of the liquid sample. This controlled atmosphere allowed the investigation of the source of the reactive oxygen species induced in aqueous solutions by He-water vapor plasma. The use of isotopically labelled water allowed distinguishing between the species originating in the gas phase and those formed in the liquid. The plasma equipment was contained inside a Faraday cage to eliminate possible influence of any external field. The setup is versatile and can aid in further understanding the cold plasma-liquid interactions chemistry.

  20. Pulmonary and heart diseases with inhalation of atmospheric pressure plasma flow

    Science.gov (United States)

    Hirata, Takamichi; Murata, Shigeru; Kishimoto, Takumi; Tsutsui, Chihiro; Kondo, Akane; Mori, Akira

    2012-10-01

    We examined blood pressure in the abdominal aorta of mini pig under plasma inhalation of atmospheric pressure plasma flow. The coaxial atmospheric pressure plasma source has a tungsten wire inside a glass capillary, that is surrounded by a grounded tubular electrode. Plasma was generated under the following conditions; applied voltage: 8 kVpp, frequency: 3 kHz, and helium (He) gas flow rate: 1 L/min. On the other hand, sphygmomanometry of a blood vessel proceeded using a device comprising a disposable force transducer, and a bedside monitor for simultaneous electrocardiography and signal pressure measurements. We directly measured Nitric oxide (NO) using a catheter-type NO sensor placed in the coronary sinus through an angiography catheter from the abdomen. Blood pressure decreased from 110/65 to 90/40 mm Hg in the animals in vivo under plasma inhalation. The NO concentration in the abdominal aorta like the blood pressure, reached a maximum value at about 40 s and then gradually decreased.

  1. Atmospheric pressure cold plasma synthesis of submicrometer-sized pharmaceuticals with improved physicochemical properties

    NARCIS (Netherlands)

    Radacsi, N.; Ambrus, R.; Szabó-Révész, P.; Heijden, A.E.D.M. van der; Horst, J.H. ter

    2012-01-01

    A reduction in particle size is one of the strategies to enhance the dissolution behavior of low water-soluble drugs such as niflumic acid. Atmospheric pressure cold plasma crystallization is a novel technique to achieve such submicrometer particles. This technique uses a surface dielectric barrier

  2. Liquid fuel reforming using microwave plasma at atmospheric pressure

    Science.gov (United States)

    Miotk, Robert; Hrycak, Bartosz; Czylkowski, Dariusz; Dors, Miroslaw; Jasinski, Mariusz; Mizeraczyk, Jerzy

    2016-06-01

    Hydrogen is expected to be one of the most promising energy carriers. Due to the growing interest in hydrogen production technologies, in this paper we present the results of experimental investigations of thermal decomposition and dry reforming of two alcohols (ethanol and isopropanol) in the waveguide-supplied metal-cylinder-based nozzleless microwave (915 MHz) plasma source (MPS). The hydrogen production experiments were preceded by electrodynamics properties investigations of the used MPS and plasma spectroscopic diagnostics. All experimental tests were performed with the working gas (nitrogen or carbon dioxide) flow rate ranging from 1200 to 3900 normal litres per hour and an absorbed microwave power up to 5 kW. The alcohols were introduced into the plasma using an induction heating vaporizer. The ethanol thermal decomposition resulted in hydrogen selectivity up to 100%. The hydrogen production rate was up to 1150 NL(H2) h-1 and the energy yield was 267 NL(H2) kWh-1 of absorbed microwave energy. Due to intense soot production, the thermal decomposition process was not appropriate for isopropanol conversion. Considering the dry reforming process, using isopropanol was more efficient in hydrogen production than ethanol. The rate and energy yield of hydrogen production were up to 1116 NL(H2) h-1 and 223 NL(H2) kWh-1 of microwave energy used, respectively. However, the hydrogen selectivity was no greater than 37%. Selected results given by the experiment were compared with the results of numerical modeling.

  3. Development of superhydrophobic surface on glass substrate by multi-step atmospheric pressure plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Han, Duksun [Department of Applied Plasma Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabuk-do 561-756 (Korea, Republic of); Moon, Se Youn, E-mail: symoon@jbnu.ac.kr [Department of Applied Plasma Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabuk-do 561-756 (Korea, Republic of); Department of Quantum system Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabuk-do 561-756 (Korea, Republic of)

    2015-07-31

    Superhydrophobic surface was prepared on a glass by helium based CH{sub 4} and C{sub 4}F{sub 8} atmospheric pressure plasmas, and its water wettability was investigated by a water droplet contact angle method. The water droplet spread over on the untreated glasses that showed the initial hydrophilic property of the glass surface. Then, the static contact angles became about 85° and 98° after a single step CH{sub 4} plasma treatment and a single step C{sub 4}F{sub 8} plasma treatment, respectively. The contact angle was remarkably increased to 152°, indicating a superhydrophobic property, after a sequential multi-step CH{sub 4} and C{sub 4}F{sub 8} plasma treatment. From the X-ray photoelectron spectroscopy and the field emission scanning electron microscope measurements, it was found that the physical morphologies and the chemical compositions were depending on the substrate materials, which were important factors for the superhydrophobicity. - Highlights: • Development of rapid and simple method for superhydrophobic surface • Effects of atmospheric pressure plasma for superhydrophobic surface preparation • Observation of chemical and physical surface modification by atmospheric pressure plasma • Effects of substrate properties for plasma–surface interaction.

  4. Efficacy of Atmospheric Pressure Plasma as an Antibacterial Agent Against Enterococcus Faecalis in Vitro

    Science.gov (United States)

    Cao, Yingguang; Yang, Ping; Lu, Xinpei; Xiong, Zilan; Ye, Tao; Xiong, Qing; Sun, Ziyong

    2011-02-01

    Enterococcus faecalis (E. faecalis) is a microorganism that can survive extreme challenges in obturated root canals. The aim of this study was to evaluate the efficacy of a non-thermal atmospheric pressure plasma plume against E. faecalis in vitro. A non-thermal atmospheric pressure plasma jet device which could generate a cold plasma plume carrying a peak current of 300 mA was used. The antibacterial efficacy of this device against E. faecalis and its biofilm under different conditions was detected. The antibacterial efficacy of the plasma against E. faecalis and Staphylococcus aureus (S. aureus) was also evaluated. After plasma treatment, the average diameter of inhibition zone on S. aureus and E. faecalis was 2.62±0.26 cm and 1.06±0.30 cm, respectively (P faecalis biofilm (P faecalis were observed after treatment for 2 min. It is concluded that the non-thermal atmospheric pressure plasma could serve as an effective adjunct to standard endodontic microbial treatment.

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

    Science.gov (United States)

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

    2010-11-01

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

  6. An atmospheric-pressure, high-aspect-ratio, cold micro-plasma.

    Science.gov (United States)

    Lu, X; Wu, S; Gou, J; Pan, Y

    2014-01-01

    An atmospheric pressure nonequilibrium Ar micro-plasma generated inside a micro-tube with plasma radius of 3 μm and length of 2.7 cm is reported. The electron density of the plasma plume estimated from the broadening of the Ar emission line reaches as high as 3 × 10(16) cm(-3). The electron temperature obtained from CR model is 1.5 ev while the gas temperature of the plasma estimated from the N2 rotational spectrum is close to room temperature. The sheath thickness of the plasma could be close to the radius of the plasma. The ignition voltages of the plasma increase one order when the radius of the dielectric tube is decreased from 1 mm to 3 μm.

  7. Subtarget Effect on Laser Plasma Generated by Transversely Excited Atmospheric CO2 Laser at Atmospheric Gas Pressure

    Science.gov (United States)

    Kagawa, Kiichiro; Lie, Tjung Jie; Hedwig, Rinda; Abdulmajid, Syahrun Nur; Suliyanti, Maria Margaretha; Kurniawan, Hendrik

    2000-05-01

    An experimental study has been carried out on the dynamical process taking place in the laser plasma generated by Transversely Excited Atmospheric CO2 laser (100 mJ, 50 ns) irradiation of a soft sample at surrounding helium pressure of 1 atm. It is shown that the presence of a copper subtarget behind the soft sample is crucial in raising the gushing speed of the atoms to the level adequate for the generation of shock wave laser plasma even at atmospheric pressure. It is also found that the time profiles of spatially integrated emission intensity of the target’s atoms and gas atoms exhibit a characteristic dynamical process that consists of successive excitation and cooling stages even at such a high pressure, which is typical of shock wave laser plasma. It is therefore suggested that the generation of the laser plasma at atmospheric pressure is more likely due to the shock wave mechanism than to the widely known breakdown mechanism. Initial spectrochemical analysis of water from the blow off of a boiler system was also carried out, showing a detection limit of as low as 5 ppm for calcium.

  8. EDITORIAL: Atmospheric pressure non-thermal plasmas for processing and other applications

    Science.gov (United States)

    Massines, Françoise

    2005-02-01

    Interest has grown over the past few years in applying atmospheric pressure plasmas to plasma processing for the benefits this can offer to existing and potential new processes, because they do not require expensive vacuum systems and batch processing. There have been considerable efforts to efficiently generate large volumes of homogeneous atmospheric pressure non-thermal plasmas to develop environmentally friendly alternatives for surface treatment, thin film coating, sterilization, decontamination, etc. Many interesting questions have arisen that are related to both fundamental and applied research in this field. Many concern the generation of a large volume discharge which remains stable and uniform at atmospheric pressure. At this pressure, depending on the experimental conditions, either streamer or Townsend breakdown may occur. They respectively lead to micro-discharges or to one large radius discharge, Townsend or glow. However, the complexity arises from the formation of large radius streamers due to avalanche coupling and from the constriction of the glow discharge due to too low a current. Another difficulty is to visually distinguish many micro-discharges from one large radius discharge. Other questions relate to key chemical reactions in the plasma and at the surface. Experimental characterization and modelling also need to be developed to answer these questions. This cluster collects up-to-date research results related to the understanding of different discharges working at atmospheric pressure and the application to polymer surface activation and thin film coating. It presents different solutions for generating and sustaining diffuse discharges at atmospheric pressure. DC, low-frequency and radio-frequency excitations are considered in noble gases, nitrogen or air. Two specific methods developed to understand the transition from Townsend to streamer breakdown are also presented. They are based on the cross-correlation spectroscopy and an electrical

  9. Polysilicon Prepared from SIC14 by Atmospheric-Pressure Non-Thermal Plasma%Polysilicon Prepared from SIC14 by Atmospheric-Pressure Non-Thermal Plasma

    Institute of Scientific and Technical Information of China (English)

    李小松; 王楠; 杨晋华; 王友年; 朱爱民

    2011-01-01

    Non-thermal plasma at atmospheric pressure was explored for the preparation of polysilicon from SiCl4. The power supply sources of positive pulse and alternating current (8 kHz and 100 kHz) were compared for polysilicon preparation. The samples prepared by using the 100 kHz power source were crystalline silicon. The effects of H2 and SiCl4 volume fractions were investigated. The optical emission spectra showed that silicon species played an important role in polysilicon deposition

  10. Optical diagnostics of reactive species in atmospheric-pressure nonthermal plasma

    Science.gov (United States)

    Ono, Ryo

    2016-03-01

    This paper reviews optical measurements of reactive species in atmospheric-pressure nonthermal plasmas: streamer discharge, dielectric barrier discharge (DBD), plasma jet, and plasma-assisted ignition and combustion. Measurements of OH, O, N, {{\\text{O}}3} , NO, {{\\text{N}}2} (A, B, C), {{\\text{O}}2} (a, b), {{\\text{N}}2}(v) , {{\\text{O}}2}(v) , He*, Ar*, \\text{N}2+ , CH, and CH2O by laser-induced fluorescence, absorption, optical emission spectroscopy, and coherent anti-Stokes Raman scattering methods are included. Reactive species measurement in low-frequency (\\cong 1 Hz) pulsed streamer discharge is introduced, and reactive species production and reaction processes indicated by these measurements are described in detail. Measurements in high-frequency DBD, atmospheric-pressure diffuse discharge, and dc corona discharge are described. Measurements in plasma jets are also reviewed: rf plasma jets, kHz plasma jets, and additional plasma jets. Finally, measurements in plasma-assisted ignition and combustion are described and reviewed in addition to measurements in conventional spark ignition. A comprehensive list of the reviewed measurements is provided.

  11. Power dissipated in a non-thermal atmospheric pressure plasma jet measured by miniaturized electrical probes

    Science.gov (United States)

    Golda, Judith; Schulz-von der Gathen, Volker

    2016-09-01

    Non-thermal atmospheric pressure plasma jets are used in bio-medicine, because they generate reactive species at a low gas temperature. Knowledge and control of plasma parameters is required for stable and reliable operation. Therefore, measuring dissipated power in these plasmas is necessary. However, this is challenging because the delivered sender power is often orders of magnitudes higher than the power dissipated in the discharge itself. To measure this dissipated power, we built miniaturized electrical probes directly attached to the jet device. We observed that the dissipated power is a more comprehensive parameter than the common parameter voltage: For example, gas temperature and emission line intensities rose exponentially with increasing voltage but linearly with increasing power. Our analyses further revealed that a substantial proportion of the dissipated power is transformed into heat. In conclusion, miniaturized electrical probes give a fundamental insight into the energy balance of atmospheric pressure plasmas. In the future, these probes can also be adapted to different types of atmospheric pressure plasmas. This work was supported by DFG within the frameworks of the Package Project PAK 816.

  12. Synergistic effects of atmospheric pressure plasma-emitted components on DNA oligomers: a Raman spectroscopic study.

    Science.gov (United States)

    Edengeiser, Eugen; Lackmann, Jan-Wilm; Bründermann, Erik; Schneider, Simon; Benedikt, Jan; Bandow, Julia E; Havenith, Martina

    2015-11-01

    Cold atmospheric-pressure plasmas have become of increasing importance in sterilization processes especially with the growing prevalence of multi-resistant bacteria. Albeit the potential for technological application is obvious, much less is known about the molecular mechanisms underlying bacterial inactivation. X-jet technology separates plasma-generated reactive particles and photons, thus allowing the investigation of their individual and joint effects on DNA. Raman spectroscopy shows that particles and photons cause different modifications in DNA single and double strands. The treatment with the combination of particles and photons does not only result in cumulative, but in synergistic effects. Profilometry confirms that etching is a minor contributor to the observed DNA damage in vitro. Schematics of DNA oligomer treatment with cold atmospheric-pressure plasma.

  13. Electrical and optical properties of Ar/NH3 atmospheric pressure plasma jet

    Science.gov (United States)

    Chang, Zheng-Shi; Yao, Cong-Wei; Chen, Si-Le; Zhang, Guan-Jun

    2016-09-01

    Inspired by the Penning effect, we obtain a glow-like plasma jet by mixing ammonia (NH3) into argon (Ar) gas under atmospheric pressure. The basic electrical and optical properties of an atmospheric pressure plasma jet (APPJ) are investigated. It can be seen that the discharge mode transforms from filamentary to glow-like when a little ammonia is added into the pure argon. The electrical and optical analyses contribute to the explanation of this phenomenon. The discharge mode, power, and current density are analyzed to understand the electrical behavior of the APPJ. Meanwhile, the discharge images, APPJ's length, and the components of plasma are also obtained to express its optical characteristics. Finally, we diagnose several parameters, such as gas temperature, electron temperature, and density, as well as the density number of metastable argon atoms of Ar/NH3 APPJ to help judge the usability in its applications.

  14. Spatially resolved simulation of a radio frequency driven micro atmospheric pressure plasma jet and its effluent

    CERN Document Server

    Hemke, Torben; Gebhardt, Markus; Brinkmann, Ralf Peter; Mussenbrock, Thomas

    2011-01-01

    Radio frequency driven plasma jets are frequently employed as efficient plasma sources for surface modification and other processes at atmospheric pressure. The \\textit{radio-frequency driven micro-scaled atmospheric pressure plasma jet} ($\\mu$APPJ) is a particular variant of that concept whose geometry allows direct optical access. In this work, the characteristics of a $\\mu$APPJ operated with a helium-oxygen mixture and its interaction with a helium environment are studied by numerical simulation. The density and temperature of the electrons, as well as the concentration of all reactive species are studied both in the jet itself and in its effluent. It is found that the effluent is essentially free of charge carriers but contains a substantial amount of activated oxygen (O, O$_3$ and O$_2(^1\\Delta)$).

  15. Electron dynamics and plasma jet formation in a helium atmospheric pressure dielectric barrier discharge jet

    Energy Technology Data Exchange (ETDEWEB)

    Algwari, Q. Th. [Centre for Plasma Physics, School of Maths and Physics, Queen' s University Belfast, University Road, Belfast, Northern Ireland BT7 1NN (United Kingdom); Electronic Department, College of Electronics Engineering, Mosul University, Mosul 41002 (Iraq); O' Connell, D. [Centre for Plasma Physics, School of Maths and Physics, Queen' s University Belfast, University Road, Belfast, Northern Ireland BT7 1NN (United Kingdom); York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom)

    2011-09-19

    The excitation dynamics within the main plasma production region and the plasma jets of a kHz atmospheric pressure dielectric barrier discharge (DBD) jet operated in helium was investigated. Within the dielectric tube, the plasma ignites as a streamer-type discharge. Plasma jets are emitted from both the powered and grounded electrode end; their dynamics are compared and contrasted. Ignition of these jets are quite different; the jet emitted from the powered electrode is ignited with a slight time delay to plasma ignition inside the dielectric tube, while breakdown of the jet at the grounded electrode end is from charging of the dielectric and is therefore dependent on plasma production and transport within the dielectric tube. Present streamer theories can explain these dynamics.

  16. A battery-operated atmospheric-pressure plasma wand for biomedical applications

    Science.gov (United States)

    Pei, X.; Liu, J.; Xian, Y.; Lu, X.

    2014-04-01

    A handheld, battery-operated atmospheric-pressure plasma rod (named the plasma wand) which does not rely on an external power source (e.g. mains power or a power generator) or gas supply is reported. The plasma wand can be used for killing bacteria, fungi or viruses that are hidden in narrow channels such as the nasal cavity and ear canal, which are difficult to access using most currently available devices. Besides, the electrical characterization, plasma wand temperature, emission spectra of the plasma, ozone and OH radical concentration generated by the device, are investigated by different diagnostic methods. The ozone concentration reaches 120 ppm 1 mm away from the device and the OH concentration reaches 3.5 × 1014 cm-3 in the plasma. The preliminary bacteria inactivation experiment results show that all the bacteria samples on the microfiltration membrane are killed by this device within 30 s.

  17. Chemical modification of amino acids by atmospheric-pressure cold plasma in aqueous solution

    Science.gov (United States)

    Takai, Eisuke; Kitamura, Tsuyoshi; Kuwabara, Junpei; Ikawa, Satoshi; Yoshizawa, Shunsuke; Shiraki, Kentaro; Kawasaki, Hideya; Arakawa, Ryuichi; Kitano, Katsuhisa

    2014-07-01

    Plasma medicine is an attractive new research area, but the principles of plasma modification of biomolecules in aqueous solution remain elusive. In this study, we investigated the chemical effects of atmospheric-pressure cold plasma on 20 naturally occurring amino acids in aqueous solution. High-resolution mass spectrometry revealed that chemical modifications of 14 amino acids were observed after plasma treatment: (i) hydroxylation and nitration of aromatic rings in tyrosine, phenylalanine and tryptophan; (ii) sulfonation and disulfide linkage formation of thiol groups in cysteine; (iii) sulfoxidation of methionine and (iv) amidation and ring-opening of five-membered rings in histidine and proline. A competitive reaction experiment using 20 amino acids demonstrated that sulfur-containing and aromatic amino acids were preferentially decreased by the plasma treatment. These data provide fundamental information for elucidating the mechanism of protein inactivation for biomedical plasma applications.

  18. The Research on Atmospheric Pressure Water Vapour Plasma Generation and Application for the Destruction of Wastes

    Directory of Open Access Journals (Sweden)

    Viktorija Grigaitiene

    2013-01-01

    Full Text Available In the Lithuanian Energy Institute an experimental atmospheric pressure Ar/water vapour plasma torch has been designed and tested. The power of plasma torch was estimated 40 ÷ 69 kW, the mean temperature of plasma jet at the exhaust nozzle was 2300÷2900K. The chemical compositionof water vapour plasma was established from the emission spectrum lines at 300 ÷ 800nm range. The main species observed in Ar/water vapour plasma were: Ar, OH, H, O, Cu. The experiments on water vapour steam reforming were performed. The results confirmed that water vapour plasma has the unique properties – high enthalpy and environmentally friendly conditions. It could be employed for environmental purposes such as destruction of wastes into simple molecules or conversion to synthetic gas.

  19. Decontamination of a rotating cutting tool during operation by means of atmospheric pressure plasmas

    DEFF Research Database (Denmark)

    Leipold, Frank; Kusano, Yukihiro; Hansen, F.

    2010-01-01

    The decontamination of a rotating cutting tool used for slicing in the meat industry by means of atmospheric pressure plasmas is investigated. The target is Listeria monocytogenes, a bacterium which causes listeriosis and can be found in plants and food. The non-pathogenic species, Listeria innocua......, is used for the experiments. A rotating knife was inoculated with L. innocua. The surface of the rotating knife was partly exposed to an atmospheric pressure dielectric barrier discharge operated in air, where the knife itself served as a ground electrode. The rotation of the knife ensures a treatment...

  20. Study on an Atmospheric Pressure Plasma Jet and its Application in Etching Photo-Resistant Materials

    Institute of Scientific and Technical Information of China (English)

    李海江; 王守国; 赵玲利; 叶甜春

    2004-01-01

    An atmospheric pressure radio-frequency plasma jet that can eject cold plasma has been developed. In this paper, the configuration of this type of plasma jet is illustrated and its discharge characteristics curves are studied with a current and a voltage probe. A thermal couple is used to measure the temperature distribution along the axis of the jet stream. The temperature distribution curve is generated for the He/O2 jet stream at the discharge power of 150W. This jet can etch the photo-resistant material at an average rate of 100nm/min on the surface of silicon wafers at a right angle.

  1. Application of atmospheric pressure plasma on polyethylene for increased prosthesis adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Van Vrekhem, S., E-mail: stijn.vanvrekhem@ugent.be [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering and Architecture, Ghent University, Sint-Pietersnieuwstraat 41 B4, 9000 Ghent (Belgium); Cools, P. [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering and Architecture, Ghent University, Sint-Pietersnieuwstraat 41 B4, 9000 Ghent (Belgium); Declercq, H. [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering and Architecture, Ghent University, Sint-Pietersnieuwstraat 41 B4, 9000 Ghent (Belgium); Tissue Engineering Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, De Pintelaan 185 6B3, 9000 Ghent (Belgium); Van Tongel, A. [Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185 13K12, 9000 Ghent (Belgium); Vercruysse, C.; Cornelissen, M. [Tissue Engineering Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, De Pintelaan 185 6B3, 9000 Ghent (Belgium); De Geyter, N.; Morent, R. [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering and Architecture, Ghent University, Sint-Pietersnieuwstraat 41 B4, 9000 Ghent (Belgium)

    2015-12-01

    Biopolymers are often subjected to surface modification in order to improve their surface characteristics. The goal of this study is to show the use of plasma technology to enhance the adhesion of ultra-high molecular weight polyethylene (UHMWPE) shoulder prostheses. Two different plasma techniques (low pressure plasma activation and atmospheric pressure plasma polymerization) are performed on UHMWPE to increase the adhesion between (1) the polymer and polymethylmethacrylate (PMMA) bone cement and (2) the polymer and osteoblast cells. Both techniques are performed using a dielectric barrier discharge (DBD). A previous paper showed that low pressure plasma activation of UHMWPE results in the incorporation of oxygen-containing functional groups, which leads to an increased surface wettability. Atmospheric pressure plasma polymerization of methylmethacrylate (MMA) on UHMWPE results in a PMMA-like coating, which could be deposited with a high degree of control of chemical composition and layer thickness. The thin film also proved to be relatively stable upon incubation in a phosphate buffer solution (PBS). This paper discusses the next stage of the study, which includes testing the adhesion of the plasma-activated and plasma-polymerized samples to bone cement through pull-out tests and testing the cell adhesion and proliferation on the samples. In order to perform the pull-out tests, all samples were cut to standard dimensions and fixed in bone cement in a reproducible way with a sample holder specially designed for this purpose. The cell adhesion and proliferation were tested by means of an MTS assay and live/dead staining after culturing MC3T3 osteoblast cells on UHMWPE samples. The results show that both plasma activation and plasma polymerization significantly improve the adhesion to bone cement and enhance cell adhesion and proliferation. In conclusion, it can be stated that the use of plasma technology can lead to an implant with improved quality and a subsequent

  2. Shock Formation by Plasma Filaments of Microwave Discharge under Atmospheric Pressure

    Science.gov (United States)

    Takahashi, Masayuki; Ohnishi, Naofumi

    2016-03-01

    A one-dimensional compressible fluid calculation was coupled with a finite- difference time-domain code and a particle-in-cell code with collision to reproduce propagation of electromagnetic wave, ionization process of plasma, and shock wave formation in atmospheric microwave discharge. Plasma filaments are driven toward the microwave source at 1 atm, and the distance between each filament is one-fifth of the wavelength of the incident microwave. The strong shock wave is generated due to the high plasma density at the atmospheric pressure. A simple analysis of the microwave propagation into the plasma shows that cut-off density of the microwave becomes smaller with the pressure decrease in a collisional plasma. At the lower pressure, the smaller density plasma is obtained with a diffusive pattern because of the smaller cut-off density and the larger diffusion effect. In contrast with the 1-atm case, the weak shock wave is generated at a rarefied condition, which lowers performance of microwave thruster.

  3. Development of a new atmospheric pressure cold plasma jet generator and application in sterilization

    Institute of Scientific and Technical Information of China (English)

    Cheng Cheng; Liu Peng; Xu Lei; Zhang Li-Ye; Zhan Ru-Juan; Zhang Wen-Rui

    2006-01-01

    This paper reports that a new plasma generator at atmospheric pressure, which is composed of two homocentric cylindrical all-metal tubes, successfully generates a cold plasma jet. The inside tube electrode is connected to ground,the outside tube electrode is connected to a high-voltage power supply, and a dielectric layer is covered on the outside tube electrode. When the reactor is operated by low-frequency (6 kHz-20 kHz) AC supply in atmospheric pressure and argon is steadily fed as a discharge gas through inside tube electrode, a cold plasma jet is blown out into air and the plasma gas temperature is only 25-30 ℃. The electric character of the discharge is studied by using digital real-time oscilloscope (TDS 200-Series), and the discharge is capacitive. Preliminary results are presented on the decontamination of E.colis bacteria and Bacillus subtilis bacteria by this plasma jet, and an optical emission analysis of the plasma jet is presented in this paper. The ozone concentration generated by the plasma jet is 1.0 × 1016cm-3 which is acquired by using the ultraviolet absorption spectroscopy.

  4. The jet-stream channels of gas and plasma in atmospheric-pressure plasma jets

    Science.gov (United States)

    Cho, Guangsup; Kim, Yunjung; Uhm, Han Sup

    2016-08-01

    A solution to the fluid momentum equation for incompressible steady-state flow is obtained for the streams of gas and plasma inside a jet nozzle and in the open-air space. Three pressure forces are considered in the equation. The first is the pressure force of the shear stress resulting from the flow viscosity and is balanced against the second pressure force of the gas stream that is ejected into the air. The third pressure force is due to the radial expansion of the fluid channel, reducing the velocity of the fluid to zero so that we obtain the reaching distance of the fluid after ejection from the nozzle. From the solution for the fluid channel, the regional profile and the density profile of the plasma flow are also determined. The maximum distance of the gas flow with a critical Reynolds number of R nc ≈ 2000 is calculated to be 100 times that of the nozzle diameter for Ar, Ne, and He. Because the radial expansion of the plasma is ten times larger than that of neutral gases, the length of the plasma flume is a few tens of the nozzle diameter, which is significantly shorter than the gas flow distance. In the experiments, the maximum length of the plasma plume increases and then saturates as the operation voltage increases.

  5. Fast low-temperature plasma reduction of monolayer graphene oxide at atmospheric pressure

    Science.gov (United States)

    Bodik, Michal; Zahoranova, Anna; Micusik, Matej; Bugarova, Nikola; Spitalsky, Zdenko; Omastova, Maria; Majkova, Eva; Jergel, Matej; Siffalovic, Peter

    2017-04-01

    We report on an ultrafast plasma-based graphene oxide reduction method superior to conventional vacuum thermal annealing and/or chemical reduction. The method is based on the effect of non-equilibrium atmospheric-pressure plasma generated by the diffuse coplanar surface barrier discharge in proximity of the graphene oxide layer. As the reduction time is in the order of seconds, the presented method is applicable to the large-scale production of reduced graphene oxide layers. The short reduction times are achieved by the high-volume power density of plasma, which is of the order of 100 W cm‑3. Monolayers of graphene oxide on silicon substrate were prepared by a modified Langmuir–Schaefer method and the efficient and rapid reduction by methane and/or hydrogen plasma was demonstrated. The best results were obtained for the graphene oxide reduction in hydrogen plasma, as verified by x-ray photoelectron spectroscopy and Raman spectroscopy.

  6. Influence of dissociative recombination on the LTE of argon high-frequency plasmas at atmospheric pressure

    CERN Document Server

    Sainz, A; García, M C; Calzada, M D; Sainz, Abel; Margot, Joelle; Garcia, Maria Carmen; Calzada, Maria Dolores

    2004-01-01

    This work presents a few preliminary results from a collisional-radiative (CR) model intended to describe an argon microwave (2.45 GHz) plasma at atmospheric pressure. This model aims to investigate the influence of dissociative recombination products on the Saha-Boltzmann plasma equilibrium. The model is tested through comparison with experimental results obtained in an argon plasma column generated by a traveling electromagnetic surface-wave, which is suitable to perform a parametric investigation of the plasma. It is shown that dissociative recombination predominantly populates the 4s levels and the ground state. It is further observed that it strongly influences the population of the levels, specially those of lower energy. However, the higher levels (close to the ionization limit) appear to be in equilibrium whatever the plasma density. This allows assuming that the excitation temperature Texc determined from the upper levels in the atomic system in the Boltzmann-plot is equal to Te.

  7. Turbulent jet flow generated downstream of a low temperature dielectric barrier atmospheric pressure plasma device

    Science.gov (United States)

    Whalley, Richard D.; Walsh, James L.

    2016-08-01

    Flowing low temperature atmospheric pressure plasma devices have been used in many technological applications ranging from energy efficient combustion through to wound healing and cancer therapy. The generation of the plasma causes a sudden onset of turbulence in the inhomogeneous axisymmetric jet flow downstream of the plasma plume. The mean turbulent velocity fields are shown to be self-similar and independent of the applied voltage used to generate the plasma. It is proposed that the production of turbulence is related to a combination of the small-amplitude plasma induced body forces and gas heating causing perturbations in the unstable shear layers at the jet exit which grow as they move downstream, creating turbulence.

  8. Atmospheric Pressure Non-Equilibrium Plasma as a Green Tool to Crosslink Gelatin Nanofibers

    Science.gov (United States)

    Liguori, Anna; Bigi, Adriana; Colombo, Vittorio; Focarete, Maria Letizia; Gherardi, Matteo; Gualandi, Chiara; Oleari, Maria Chiara; Panzavolta, Silvia

    2016-12-01

    Electrospun gelatin nanofibers attract great interest as a natural biomaterial for cartilage and tendon repair despite their high solubility in aqueous solution, which makes them also difficult to crosslink by means of chemical agents. In this work, we explore the efficiency of non-equilibrium atmospheric pressure plasma in stabilizing gelatin nanofibers. We demonstrate that plasma represents an innovative, easy and environmentally friendly approach to successfully crosslink gelatin electrospun mats directly in the solid state. Plasma treated gelatin mats display increased structural stability and excellent retention of fibrous morphology after immersion in aqueous solution. This method can be successfully applied to induce crosslinking both in pure gelatin and genipin-containing gelatin electrospun nanofibers, the latter requiring an even shorter plasma exposure time. A complete characterization of the crosslinked nanofibres, including mechanical properties, morphological observations, stability in physiological solution and structural modifications, has been carried out in order to get insights on the occurring reactions triggered by plasma.

  9. Characterisation of PMMA/ATH Layers Realised by Means of Atmospheric Pressure Plasma Powder Deposition

    Directory of Open Access Journals (Sweden)

    Lena M. Wallenhorst

    2015-01-01

    Full Text Available We report on the characteristics of aluminium trihydrate filled poly(methyl methacrylate composite (PMMA/ATH coatings realised by plasma deposition at atmospheric pressure. For this purpose, PMMA/ATH powder was fed to a plasma jet where the process and carrier gas was compressed air. The deposited coatings were investigated by X-ray photoelectron spectroscopy and water contact angle measurements. Further, the raw material was characterised before deposition. It was found that, with respect to the raw material, aluminium was uncovered in the course of the plasma deposition process which can be explained by plasma-induced etching of the PMMA matrix. As a result, the wettability of plasma-deposited PMMA/ATH was significantly increased. Even though a uniform coating film could not be realised as ascertained by confocal laser scanning microscopy, the deposited coatings feature notably enhanced characteristics which could be advantageous for further processing.

  10. Turbulent jet flow generated downstream of a low temperature dielectric barrier atmospheric pressure plasma device.

    Science.gov (United States)

    Whalley, Richard D; Walsh, James L

    2016-08-26

    Flowing low temperature atmospheric pressure plasma devices have been used in many technological applications ranging from energy efficient combustion through to wound healing and cancer therapy. The generation of the plasma causes a sudden onset of turbulence in the inhomogeneous axisymmetric jet flow downstream of the plasma plume. The mean turbulent velocity fields are shown to be self-similar and independent of the applied voltage used to generate the plasma. It is proposed that the production of turbulence is related to a combination of the small-amplitude plasma induced body forces and gas heating causing perturbations in the unstable shear layers at the jet exit which grow as they move downstream, creating turbulence.

  11. Influence of ethylene glycol pretreatment on effectiveness of atmospheric pressure plasma treatment of polyethylene fibers

    Energy Technology Data Exchange (ETDEWEB)

    Wen Ying; Li Ranxing [Key Laboratory of Textile Science and Technology (Donghua University), Ministry of Education (China); Cai Fang [Key Laboratory of Eco-Textiles (Donghua University), Ministry of Education (China); Fu Kun; Peng Shujing; Jiang Qiuran; Yao Lan [Key Laboratory of Textile Science and Technology (Donghua University), Ministry of Education (China); Qiu Yiping, E-mail: ypqiu@dhu.edu.cn [Department of Textile Materials Science and Product Design, College of Textiles, Donghua University, Shanghai 201620 (China)

    2010-03-01

    For atmospheric pressure plasma treatments, the results of plasma treatments may be influenced by liquids adsorbed into the substrate. This paper studies the influence of ethylene glycol (EG) pretreatment on the effectiveness of atmospheric plasma jet (APPJ) treatment of ultrahigh molecular weight polyethylene (UHMWPE) fibers with 0.31% and 0.42% weight gain after soaked in EG/water solution with concentration of 0.15 and 0.3 mol/l for 24 h, respectively. Scanning electron microscopy (SEM) shows that the surface of fibers pretreated with EG/water solution does not have observable difference from that of the control group. The X-ray photoelectron spectroscopy (XPS) results show that the oxygen concentration on the surface of EG-pretreated fibers is increased less than the plasma directly treated fibers. The interfacial shear strength (IFSS) of plasma directly treated fibers to epoxy is increased almost 3 times compared with the control group while that of EG-pretreated fibers to epoxy does not change except for the fibers pretreated with lower EG concentration and longer plasma treatment time. EG pretreatment reduces the water contact angle of UHMWPE fibers. In conclusion, EG pretreatment can hamper the effect of plasma treatment of UHMWPE fibers and therefore longer plasma treatment duration is required for fibers pretreated with EG.

  12. DNA damage in oral cancer cells induced by nitrogen atmospheric pressure plasma jets

    Science.gov (United States)

    Han, Xu; Klas, Matej; Liu, Yueying; Stack, M. Sharon; Ptasinska, Sylwia

    2013-09-01

    The nitrogen atmospheric pressure plasma jet (APPJ) has been shown to effectively induce DNA double strand breaks in SCC-25 oral cancer cells. The APPJ source constructed in our laboratory consists of two external electrodes wrapping around a quartz tube and nitrogen as a feed gas and operates based on dielectric barrier gas discharge. Generally, it is more challenging to ignite plasma in N2 atmosphere than in noble gases. However, this design provides additional advantages such as lower costs compared to the noble gases for future clinical operation. Different parameters of the APPJ configuration were tested in order to determine radiation dosage. To explore the effects of delayed damage and cell self-repairing, various incubation times of cells after plasma treatment were also performed. Reactive species generated in plasma jet and in liquid environment are essential to be identified and quantified, with the aim of unfolding the mystery of detailed mechanisms for plasma-induced cell apoptosis. Moreover, from the comparison of plasma treatment effect on normal oral cells OKF6T, an insight to the selectivity for cancer treatment by APPJ can be explored. All of these studies are critical to better understand the damage responses of normal and abnormal cellular systems to plasma radiation, which are useful for the development of advanced plasma therapy for cancer treatment at a later stage.

  13. Formation and characterization of hydrophobic glass surface treated by atmospheric pressure He/CH4 plasma

    Science.gov (United States)

    Noh, Sooryun; Youn Moon, Se

    2014-01-01

    Atmospheric pressure helium plasmas, generated in the open air by 13.56 MHz rf power, were applied for the glass surface wettability modification. The plasma gas temperature, measured by the spectroscopic method, was under 400 K which is low enough to treat the samples without thermal damages. The hydrophobicity of the samples determined by the water droplet contact angle method was dependent on the methane gas content and the plasma exposure time. Adding the methane gas by a small amount of 0.25%, the contact angle was remarkably increased from 10° to 83° after the 10 s plasma treatment. From the analysis of the treated surface and the plasma, it was shown that the deposition of alkane functional groups such as C-H stretch, CH2 bend, and CH3 bend was one of the contributing factors for the hydrophobicity development. In addition, the hydrophobic properties lasted over 2 months even after the single treatment. From the results, the atmospheric pressure plasma treatment promises the fast and low-cost method for the thermally-weak surface modification.

  14. Application of Atmospheric-Pressure Microwave Line Plasma for Low Temperature Process

    Science.gov (United States)

    Suzuki, Haruka; Nakano, Suguru; Itoh, Hitoshi; Sekine, Makoto; Hori, Masaru; Toyoda, Hirotaka

    2015-09-01

    Atmospheric pressure (AP) plasmas have been given much attention because of its high cost benefit and a variety of possibilities for industrial applications. In various kinds of plasma production technique, pulsed-microwave discharge plasma using slot antenna is attractive due to its ability of high-density and stable plasma production. In this plasma source, however, size of the plasma has been limited up to a few cm in length due to standing wave inside a waveguide. To solve this, we have proposed a newly-developed AP microwave plasma source that utilizes not standing wave but travelling wave. By using this plasma source, spatially-uniform AP line plasma with 40 cm in length was realized by pure helium discharge in 60 cm slot and with nitrogen gas additive of 1%. Furthermore, gas temperature as low as 400 K was realized in this device. In this study, as an example of low temperature processes, hydrophilic treatment of PET films was performed. Processing speed increased with pulse frequency and a water contact angle of ~20° was easily obtained within 5 s with no thermal damage to the substrate. To evaluate treatment-uniformity of long line length, PET films were treated by 90 cm slot-antenna plasma and uniform treatment performance was confirmed.

  15. Cold atmospheric-pressure plasma and bacteria: understanding the mode of action using vibrational microspectroscopy

    Science.gov (United States)

    Kartaschew, Konstantin; Baldus, Sabrina; Mischo, Meike; Bründermann, Erik; Awakowicz, Peter; Havenith, Martina

    2016-09-01

    Cold atmospheric-pressure plasma show promising antimicrobial effects, however the detailed biochemical mechanism of the bacterial inactivation is still unknown. We investigated, for the first time, plasma-treated Gram-positive Bacillus subtilis and Gram-negative Escherichia coli bacteria with Raman and infrared microspectroscopy. A dielectric barrier discharge was used as a plasma source. We were able to detect several plasma-induced chemical modifications, which suggest a pronounced oxidative effect on the cell envelope, cellular proteins and nucleotides as well as a generation of organic nitrates in the treated bacteria. Vibrational microspectroscopy is used as a comprehensive and a powerful tool for the analysis of plasma interactions with whole organisms such as bacteria. Analysis of reaction kinetics of chemical modifications allow a time-dependent insight into the plasma-mediated impact. Investigating possible synergistic effects between the plasma-produced components, our observations strongly indicate that the detected plasma-mediated chemical alterations can be mainly explained by the particle effect of the generated reactive species. By changing the polarity of the applied voltage pulse, and hence the propagation mechanisms of streamers, no significant effect on the spectral results could be detected. This method allows the analysis of the individual impact of each plasma constituent for particular chemical modifications. Our approach shows great potential to contribute to a better understanding of plasma-cell interactions.

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

    Science.gov (United States)

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

    2017-02-01

    In this work, we report on aluminum oxide (Al2O3) gas permeation barriers prepared by spatial ALD (SALD) at atmospheric pressure. We compare the growth characteristics and layer properties using trimethylaluminum (TMA) in combination with an Ar/O2 remote atmospheric pressure plasma for different substrate velocities and different temperatures. The resulting Al2O3 films show ultralow water vapor transmission rates (WVTR) on the order of 10(-6) gm(-2)d(-1). In notable contrast, plasma based layers already show good barrier properties at low deposition temperatures (75 °C), while water based processes require a growth temperature above 100 °C to achieve equally low WVTRs. The activation energy for the water permeation mechanism was determined to be 62 kJ/mol.

  17. The plasma footprint of an atmospheric pressure plasma jet on a flat polymer substrate and its relation to surface treatment

    Science.gov (United States)

    Onyshchenko, Iuliia; Nikiforov, Anton Yu.; De Geyter, Nathalie; Morent, Rino

    2016-08-01

    The aim of this work is to show the correlation between the plasma propagation in the footprint of an atmospheric pressure plasma jet on a flat polymer surface and the plasma treatment impact on the polymer properties. An argon plasma jet working in open air is used as plasma source, while PET thin films are used a substrates for plasma treatment. Light emission photographs are taken with an ICCD camera to have a close look at the generated structures in the plasma jet footprint on the surface. Water contact angle (WCA) measurement and X-ray photoelectron spectroscopy (XPS) analysis are also performed to obtain information about the impact of the plasma treatment on the PET surface characteristics. A variation in ICCD camera gate duration (1 µs, 100 µs, 50 ms) results in the photographs of the different plasma structures occurring during the plasma propagation on the flat PET surface. Contact angle measurements provide results on improvement of the PET hydrophilic character, while XPS analysis shows the distribution of atomic elements on the treated substrate surface. Light emission images help explaining the obtained WCA and XPS results. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  18. Chemically reactive species in liquids generated by atmospheric-pressure plasmas and their roles in plasma medicine

    Energy Technology Data Exchange (ETDEWEB)

    Hamaguchi, Satoshi [Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2013-07-11

    Plasmas whose gas temperatures are close to room temperature may be generated in ambient air or a gas at atmospheric pressure with the use of low-frequency high voltage or low-power radio-frequency (RF) or microwave power applied to electrodes. Such plasmas can serve as a powerful source of free radicals and/or chemically reactive species that arise from atoms and molecules of the ambient gas. Recently use of such plasmas for medical purposes has attracted much attention as they can be implemented in possible medical devices that can cause blood coagulation, heal wounds, facilitate angiogenesis, sterilize surgical devices as well as living tissues without harming healthy cells, and selectively inactivate cancer cells. Especially of interest among reactive species generated by atmospheric-pressure plasmas (APP) are reactive oxygen species (ROS) and reactive nitrogen species (RNS) that are generated in liquid phase. Since most living tissues and cells are immersed in liquids (such as blood or culture media), reactive species generated by APPs in the gas phase are transported to the liquid phase and possibly converted to different types of reactive species therein before causing some influence on the tissues or cells. In this study, the rate equations are solved to evaluate concentrations of various reactive species in pure water that are originated by plasma reactions in atmosphere and possible effects of such species (including ROS/RNS) on living tissues and cells are discussed.

  19. In situ modification of chromatography adsorbents using cold atmospheric pressure plasmas

    Science.gov (United States)

    Olszewski, P.; Willett, T. C.; Theodosiou, E.; Thomas, O. R. T.; Walsh, J. L.

    2013-05-01

    Efficient manufacturing of increasingly sophisticated biopharmaceuticals requires the development of new breeds of chromatographic materials featuring two or more layers, with each layer affording different functions. This letter reports the in situ modification of a commercial beaded anion exchange adsorbent using atmospheric pressure plasma generated within gas bubbles. The results show that exposure to He-O2 plasma in this way yields significant reductions in the surface binding of plasmid DNA to the adsorbent exterior, with minimal loss of core protein binding capacity; thus, a bi-layered chromatography material exhibiting both size excluding and anion exchange functionalities within the same bead is produced.

  20. Atmospheric Pressure Plasma Jet as a Dry Alternative to Inkjet Printing in Flexible Electronics

    Science.gov (United States)

    Gandhiraman, Ram Prasad; Lopez, Arlene; Koehne, Jessica; Meyyappan, M.

    2016-01-01

    We have developed an atmospheric pressure plasma jet printing system that works at room temperature to 50 deg C unlike conventional aerosol assisted techniques which require a high temperature sintering step to obtain desired thin films. Multiple jets can be configured to increase throughput or to deposit multiple materials, and the jet(s) can be moved across large areas using a x-y stage. The plasma jet has been used to deposit carbon nanotubes, graphene, silver nanowires, copper nanoparticles and other materials on substrates such as paper, cotton, plastic and thin metal foils.

  1. Stability of Atmospheric-Pressure Plasma Induced Changes on Polycarbonate Surfaces

    Science.gov (United States)

    Sharma, Rajesh; Holcomb, Edward; Trigwell, Steve

    2006-01-01

    Polycarbonate films are subjected to plasma treatment in a number of applications such as improving adhesion between polycarbonate and silicon alloy in protective and optical coatings. The changes in surface chemistry due to plasma treatment have tendency to revert back. Thus stability of the plasma induced changes on polymer surfaces over desired time period is very important. The objective of this study was to examine the effect of ageing on atmospheric pressure helium-plasma treated polycarbonate (PC) sample as a function of treatment time. The ageing effects were studied over a period of 10 days. The samples were plasma treated for 0.5, 2, 5 and 10 minutes. Contact angle measurements were made to study surface energy changes. Modification of surface chemical structure was examined using, X-ray Photoelectron Spectroscopy (XPS). Contact angle measurements on untreated and plasma treated surfaces were made immediately, 24, 48, 72 and 96 hrs after treatment. Contact angle decreased from 93 deg for untreated sample to 30 deg for sample plasma treated for 10 minutes. After 10 days the contact angles for the 10 minute plasma treated sample increased to 67 deg, but it never reverted back to that of untreated surface. Similarly the O/C ratio increased from 0.136 for untreated sample to 0.321 for 10 minute plasma treated sample indication increase in surface energy.

  2. Gliding arc triggered microwave plasma arc at atmospheric pressure for coal gasification application

    Science.gov (United States)

    Jain, Vishal; Visani, A.; Patil, C.; Patel, B. K.; Sharma, P. K.; John, P. I.; Nema, S. K.

    2014-08-01

    Plasma torch is device that efficiently converts electrical energy in to thermal energy for various high temperature applications. The conventional plasma torch comprises of consumable electrodes namely anode and cathode electrodes. The replacement of these electrodes is a complex process owing to its cooling and process shut down requirements. However, microwave plasma arc is electrode-less plasma arc system that is an alternative method to conventional arc technology for generating plasma arc. In this technique, microwave power is efficiently coupled to generate plasma arc by using the property of polar molecule to absorb microwave power. The absorption of microwave power is in form of losses due to intermolecular friction and high collisions between the molecules. This is an efficient method because all microwave power can be absorbed by plasma arc. The main feature of microwave plasma arc is its large uniform high temperature column which is not possible with conventional arc discharge methods. Such type of plasma discharge is very useful in applications where sufficient residence time for treat materials is required. Microwave arc does not require any consumable electrodes and hence, it can be operated continuously that makes it very useful for hazardous effluent treatment applications. Further, microwave cannot ionize neutral particles at atmospheric pressure and hence, a gliding arc is initiated between two thin electrodes in the cavity by applying very low power high voltage (3kV) AC source. In this report, the method for generating microwave arc of 1kW power using commercial microwave oven is elaborated.

  3. Fourier transform infrared absorption spectroscopy characterization of gaseous atmospheric pressure plasmas with 2 mm spatial resolution.

    Science.gov (United States)

    Laroche, G; Vallade, J; Bazinette, R; van Nijnatten, P; Hernandez, E; Hernandez, G; Massines, F

    2012-10-01

    This paper describes an optical setup built to record Fourier transform infrared (FTIR) absorption spectra in an atmospheric pressure plasma with a spatial resolution of 2 mm. The overall system consisted of three basic parts: (1) optical components located within the FTIR sample compartment, making it possible to define the size of the infrared beam (2 mm × 2 mm over a path length of 50 mm) imaged at the site of the plasma by (2) an optical interface positioned between the spectrometer and the plasma reactor. Once through the plasma region, (3) a retro-reflector module, located behind the plasma reactor, redirected the infrared beam coincident to the incident path up to a 45° beamsplitter to reflect the beam toward a narrow-band mercury-cadmium-telluride detector. The antireflective plasma-coating experiments performed with ammonia and silane demonstrated that it was possible to quantify 42 and 2 ppm of these species in argon, respectively. In the case of ammonia, this was approximately three times less than this gas concentration typically used in plasma coating experiments while the silane limit of quantification was 35 times lower. Moreover, 70% of the incoming infrared radiation was focused within a 2 mm width at the site of the plasma, in reasonable agreement with the expected spatial resolution. The possibility of reaching this spatial resolution thus enabled us to measure the gaseous precursor consumption as a function of their residence time in the plasma.

  4. Fourier transform infrared absorption spectroscopy characterization of gaseous atmospheric pressure plasmas with 2 mm spatial resolution

    Energy Technology Data Exchange (ETDEWEB)

    Laroche, G. [Laboratoire d' Ingenierie de Surface, Centre de Recherche sur les Materiaux Avances, Departement de genie des mines, de la metallurgie et des materiaux, Universite Laval, 1065, avenue de la Medecine, Quebec G1V 0A6 (Canada); Centre de recherche du CHUQ, Hopital St Francois d' Assise, 10, rue de l' Espinay, local E0-165, Quebec G1L 3L5 (Canada); Vallade, J. [Laboratoire Procedes, Materiaux et Energie Solaire, PROMES, CNRS, Technosud, Rambla de la Thermodynamique, F-66100 Perpignan (France); Agence de l' environnement et de la Ma Latin-Small-Letter-Dotless-I -carettrise de l' Energie, 20, avenue du Gresille, BP 90406, F-49004 Angers Cedex 01 (France); Bazinette, R.; Hernandez, E.; Hernandez, G.; Massines, F. [Laboratoire Procedes, Materiaux et Energie Solaire, PROMES, CNRS, Technosud, Rambla de la Thermodynamique, F-66100 Perpignan (France); Nijnatten, P. van [OMT Solutions bv, High Tech Campus 9, 5656AE Eindhoven (Netherlands)

    2012-10-15

    This paper describes an optical setup built to record Fourier transform infrared (FTIR) absorption spectra in an atmospheric pressure plasma with a spatial resolution of 2 mm. The overall system consisted of three basic parts: (1) optical components located within the FTIR sample compartment, making it possible to define the size of the infrared beam (2 mm Multiplication-Sign 2 mm over a path length of 50 mm) imaged at the site of the plasma by (2) an optical interface positioned between the spectrometer and the plasma reactor. Once through the plasma region, (3) a retro-reflector module, located behind the plasma reactor, redirected the infrared beam coincident to the incident path up to a 45 Degree-Sign beamsplitter to reflect the beam toward a narrow-band mercury-cadmium-telluride detector. The antireflective plasma-coating experiments performed with ammonia and silane demonstrated that it was possible to quantify 42 and 2 ppm of these species in argon, respectively. In the case of ammonia, this was approximately three times less than this gas concentration typically used in plasma coating experiments while the silane limit of quantification was 35 times lower. Moreover, 70% of the incoming infrared radiation was focused within a 2 mm width at the site of the plasma, in reasonable agreement with the expected spatial resolution. The possibility of reaching this spatial resolution thus enabled us to measure the gaseous precursor consumption as a function of their residence time in the plasma.

  5. Atmospheric pressure plasma: a high-performance tool for the efficient removal of biofilms.

    Directory of Open Access Journals (Sweden)

    Katja Fricke

    Full Text Available INTRODUCTION: The medical use of non-thermal physical plasmas is intensively investigated for sterilization and surface modification of biomedical materials. A further promising application is the removal or etching of organic substances, e.g., biofilms, from surfaces, because remnants of biofilms after conventional cleaning procedures are capable to entertain inflammatory processes in the adjacent tissues. In general, contamination of surfaces by micro-organisms is a major source of problems in health care. Especially biofilms are the most common type of microbial growth in the human body and therefore, the complete removal of pathogens is mandatory for the prevention of inflammatory infiltrate. Physical plasmas offer a huge potential to inactivate micro-organisms and to remove organic materials through plasma-generated highly reactive agents. METHOD: In this study a Candida albicans biofilm, formed on polystyrene (PS wafers, as a prototypic biofilm was used to verify the etching capability of the atmospheric pressure plasma jet operating with two different process gases (argon and argon/oxygen mixture. The capability of plasma-assisted biofilm removal was assessed by microscopic imaging. RESULTS: The Candida albicans biofilm, with a thickness of 10 to 20 µm, was removed within 300 s plasma treatment when oxygen was added to the argon gas discharge, whereas argon plasma alone was practically not sufficient in biofilm removal. The impact of plasma etching on biofilms is localized due to the limited presence of reactive plasma species validated by optical emission spectroscopy.

  6. Minimally-Invasive Gene Transfection by Chemical and Physical Interaction of Atmospheric Pressure Plasma Flow

    Science.gov (United States)

    Kaneko, Toshiro

    2014-10-01

    Non-equilibrium atmospheric pressure plasma irradiated to the living-cell is investigated for medical applications such as gene transfection, which is expected to play an important role in molecular biology, gene therapy, and creation of induced pluripotent stem (iPS) cells. However, the conventional gene transfection using the plasma has some problems that the cell viability is low and the genes cannot be transferred into some specific lipid cells, which is attributed to the unknown mechanism of the gene transfection using the plasma. Therefore, the time-controlled atmospheric pressure plasma flow is generated and irradiated to the living-cell suspended solution for clarifying the transfection mechanism toward developing highly-efficient and minimally- invasive gene transfection system. In this experiment, fluorescent dye YOYO-1 is used as the simulated gene and LIVE/DEAD Stain is simultaneously used for cell viability assay. By the fluorescence image, the transfection efficiency is calculated as the ratio of the number of transferred and surviving cells to total cell count. It is clarified that the transfection efficiency is significantly increased by the short-time (cell viability (>90%). This result indicates that the physical effects such as the electric field caused by the charged particles arriving at the surface of the cell membrane, and chemical effects associated with plasma-activated products in solution act synergistically to enhance the cell-membrane transport with low-damage. This work was supported by JSPS KAKENHI Grant Number 24108004.

  7. Surface modification of polyester synthetic leather with tetramethylsilane by atmospheric pressure plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kan, C.W., E-mail: tccwk@polyu.edu.hk [Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Kwong, C.H. [Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Ng, S.P. [Hong Kong Community College, The Hong Kong Polytechnic University (Hong Kong)

    2015-08-15

    Highlights: • Atmospheric pressure plasma treatment improved surface performance of polyester synthetic leather with tetramethylsilane. • XPS and FTIR confirmed the deposition of organosilanes on the sample's surface. • Contact angle increases to 138° after plasma treatment. - Abstract: Much works have been done on synthetic materials but scarcely on synthetic leather owing to its surface structures in terms of porosity and roughness. This paper examines the use of atmospheric pressure plasma (APP) treatment for improving the surface performance of polyester synthetic leather by use of a precursor, tetramethylsilane (TMS). Plasma deposition is regarded as an effective, simple and single-step method with low pollution. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) confirm the deposition of organosilanes on the sample's surface. The results showed that under a particular combination of treatment parameters, a hydrophobic surface was achieved on the APP treated sample with sessile drop static contact angle of 138°. The hydrophobic surface is stable without hydrophilic recovery 30 days after plasma treatment.

  8. Synthesis and Characterization of Nanofibrous Polyaniline Thin Film Prepared by Novel Atmospheric Pressure Plasma Polymerization Technique

    Directory of Open Access Journals (Sweden)

    Choon-Sang Park

    2016-01-01

    Full Text Available This work presents a study on the preparation of plasma-polymerized aniline (pPANI nanofibers and nanoparticles by an intense plasma cloud type atmospheric pressure plasma jets (iPC-APPJ device with a single bundle of three glass tubes. The nano size polymer was obtained at a sinusoidal wave with a peak value of 8 kV and a frequency of 26 kHz under ambient air. Discharge currents, photo-sensor amplifier, and optical emission spectrometer (OES techniques were used to analyze the plasma produced from the iPC-APPJ device. Field emission scanning electron microscopy (FE-SEM, transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FT-IR, gas chromatography-mass spectrometry (GC-MS, and gel permeation chromatography (GPC techniques were used to analyze the pPANI. FE-SEM and TEM results show that pPANI has nanofibers, nanoparticles morphology, and polycrystalline characteristics. The FT-IR and GC-MS analysis show the characteristic polyaniline peaks with evidence that some quinone and benzene rings are broken by the discharge energy. GPC results show that pPANI has high molecular weight (Mw, about 533 kDa with 1.9 polydispersity index (PDI. This study contributes to a better understanding on the novel growth process and synthesis of uniform polyaniline nanofibers and nanoparticles with high molecular weights using the simple atmospheric pressure plasma polymerization technique.

  9. Production of stable, non-thermal atmospheric pressure rf capacitive plasmas using gases other than helium or neon

    Science.gov (United States)

    Park, Jaeyoung; Henins, Ivars

    2005-06-21

    The present invention enables the production of stable, steady state, non-thermal atmospheric pressure rf capacitive .alpha.-mode plasmas using gases other than helium and neon. In particular, the current invention generates and maintains stable, steady-state, non-thermal atmospheric pressure rf .alpha.-mode plasmas using pure argon or argon with reactive gas mixtures, pure oxygen or air. By replacing rare and expensive helium with more readily available gases, this invention makes it more economical to use atmospheric pressure rf .alpha.-mode plasmas for various materials processing applications.

  10. Effect of cold atmospheric pressure He-plasma jet on DNA change and mutation

    Science.gov (United States)

    Yaopromsiri, C.; Yu, L. D.; Sarapirom, S.; Thopan, P.; Boonyawan, D.

    2015-12-01

    Cold atmospheric pressure plasma jet (CAPPJ) effect on DNA change was studied for assessment of its safety. The experiment utilized a home-developed CAPPJ using 100% helium to directly treat naked DNA plasmid pGFP (plasmid green fluorescent protein). A traversal electric field was applied to separate the plasma components and both dry and wet sample conditions were adopted to investigate various factor roles in changing DNA. Plasma species were measured by using optical emission spectroscopy. DNA topological form change was analyzed by gel electrophoresis. The plasma jet treated DNA was transferred into bacterial Escherichia coli cells for observing mutation. The results show that the He-CAPPJ could break DNA strands due to actions from charge, radicals and neutrals and potentially cause genetic modification of living cells.

  11. Effect of cold atmospheric pressure He-plasma jet on DNA change and mutation

    Energy Technology Data Exchange (ETDEWEB)

    Yaopromsiri, C. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@thep-center.org [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Sarapirom, S. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Bang Khen, Chiang Mai 50290 (Thailand); Thopan, P.; Boonyawan, D. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2015-12-15

    Cold atmospheric pressure plasma jet (CAPPJ) effect on DNA change was studied for assessment of its safety. The experiment utilized a home-developed CAPPJ using 100% helium to directly treat naked DNA plasmid pGFP (plasmid green fluorescent protein). A traversal electric field was applied to separate the plasma components and both dry and wet sample conditions were adopted to investigate various factor roles in changing DNA. Plasma species were measured by using optical emission spectroscopy. DNA topological form change was analyzed by gel electrophoresis. The plasma jet treated DNA was transferred into bacterial Escherichia coli cells for observing mutation. The results show that the He-CAPPJ could break DNA strands due to actions from charge, radicals and neutrals and potentially cause genetic modification of living cells.

  12. Interplay of discharge and gas flow in atmospheric pressure plasma jets

    Science.gov (United States)

    Jiang, Nan; Yang, JingLong; He, Feng; Cao, Zexian

    2011-05-01

    Interplay of discharge and gas flow in the atmospheric pressure plasma jets generated with three different discharge modes [N. Jiang, A. L. Ji, and Z. X. Cao, J. Appl. Phys. 106, 013308 (2009); N. Jiang, A. L. Ji, and Z. X. Cao, J. Appl. Phys. 108, 033302 (2010)] has been investigated by simultaneous photographing of both plasma plumes and gas flows in the ambient, with the former being visualized by using an optical schlieren system. Gas flow gains a forward momentum from discharge except for the case of overflow jets at smaller applied voltages. Larger applied voltage implies an elongated plasma jet only for single-electrode mode; for dielectric barrier discharge jet the plume length maximizes at a properly applied voltage. These findings can help understand the underlying processes, and are useful particularly for the economic operation of tiny helium plasma jets and jet arrays.

  13. Cold-atmospheric pressure plasma polymerization of acetylene on wood flour for improved wood plastics composites

    Science.gov (United States)

    Lekobou, William; Pedrow, Patrick; Englund, Karl; Laborie, Marie-Pierre

    2009-10-01

    Plastic composites have become a large class of construction material for exterior applications. One of the main disadvantages of wood plastic composites resides in the weak adhesion between the polar and hydrophilic surface of wood and the non-polar and hydrophobic polyolefin matrix, hindering the dispersion of the flour in the polymer matrix. To improve interfacial compatibility wood flour can be pretreated with environmentally friendly methods such as cold-atmospheric pressure plasma. The objective of this work is therefore to evaluate the potential of plasma polymerization of acetylene on wood flour to improve the compatibility with polyolefins. This presentation will describe the reactor design used to modify wood flour using acetylene plasma polymerization. The optimum conditions for plasma polymerization on wood particles will also be presented. Finally preliminary results on the wood flour surface properties and use in wood plastic composites will be discussed.

  14. Gas permeation barriers deposited by atmospheric pressure plasma enhanced atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Lukas, E-mail: lhoffmann@uni-wuppertal.de; Theirich, Detlef; Hasselmann, Tim; Räupke, André; Schlamm, Daniel; Riedl, Thomas, E-mail: t.riedl@uni-wuppertal.de [Institute of Electronic Devices, University of Wuppertal, Rainer-Gruenter-Str. 21, 42119 Wuppertal (Germany)

    2016-01-15

    This paper reports on aluminum oxide (Al{sub 2}O{sub 3}) thin film gas permeation barriers fabricated by atmospheric pressure atomic layer deposition (APPALD) using trimethylaluminum and an Ar/O{sub 2} plasma at moderate temperatures of 80 °C in a flow reactor. The authors demonstrate the ALD growth characteristics of Al{sub 2}O{sub 3} films on silicon and indium tin oxide coated polyethylene terephthalate. The properties of the APPALD-grown layers (refractive index, density, etc.) are compared to that deposited by conventional thermal ALD at low pressures. The films films deposited at atmospheric pressure show water vapor transmission rates as low as 5 × 10{sup −5} gm{sup −2}d{sup −1}.

  15. Electronic ground state OH(X) radical in a low-temperature atmospheric pressure plasma jet

    Science.gov (United States)

    Fuh, Che A.; Clark, Shane M.; Wu, Wei; Wang, Chuji

    2016-10-01

    The wide applicability of atmospheric pressure plasma jets in biomedicine stems from the presence of reactive nitrogen and oxygen species generated in these plasma jets. Knowing the absolute concentration of these reactive species is of utmost importance as it is critical, along with the particle flux obtained from the plasma feed gas flow rate to ensure that the correct dosage is applied during applications. In this study, we investigate and report the ground state OH(X) number density acquired using cavity ringdown spectroscopy, along the propagation axis (z-axis) of a cold atmospheric pressure helium plasma plume. The jet was generated by a repetitively pulsed mono-polar square wave of duration 1 μs running at a frequency of 9.9 kHz. The voltage supplied was 6.5 kV with the helium flow rate fixed at 3.6 standard liters per minute. The rotational and vibrational temperatures are simulated from the second positive system of nitrogen, N 2(C3πu-B3πg) , with the rotational temperature being spatially constant at 300 K along the propagation axis of the atmospheric pressure plasma jet while the vibrational temperature is 3620 K at the beginning of the plume and is observed to decrease downstream. The OH(A) emission intensity obtained via optical emission spectroscopy was observed to decrease downstream of the plasma jet. The OH(X) number density along the propagation axis was initially 2.2 × 1013 molecules cm-3 before increasing to a peak value of 2.4 × 1013 molecules cm-3, from which the number density was observed to decrease to 2.2 × 1013 molecules cm-3 downstream of the plasma jet. The total OH(A, X) in the plasma jet remained relatively constant along the propagation axis of the plasma jet before falling off at the tip of the jet. The increase in vibrational temperature downstream and the simultaneous measurements of both the excited state OH(A) and the ground state OH(X) reported in this study provide insights into the formation and consumption of this

  16. 50-Hz plasma treatment of glass fibre reinforced polyester at atmospheric pressure enhanced by ultrasonic irradiation

    DEFF Research Database (Denmark)

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

    2011-01-01

    Glass fibre reinforced polyester (GFRP) plates are treated using a 50-Hz dielectric barrier discharge at peak-to-peak voltage of 30 kV in helium at atmospheric pressure with and without ultrasonic irradiation to study adhesion improvement. The ultrasonic waves at the fundamental frequency of around...... 30 kHz with the sound pressure level of approximately 155 dB were introduced vertically to the GFRP surface through a cylindrical waveguide. The polar component of the surface energy was almost unchanged after the plasma treatment without ultrasonic irradiation, but drastically increased...

  17. Ultrasound enhanced 50 Hz plasma treatment of glass-fiber-reinforced polyester at atmospheric pressure

    DEFF Research Database (Denmark)

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

    2013-01-01

    Glass-fiber-reinforced polyester (GFRP) plates are treated using a 50Hz dielectric barrier discharge at a peak-to-peak voltage of 30 kV in helium at atmospheric pressure with and without ultrasonic irradiation to study adhesion improvement. The ultrasonic waves at the fundamental frequency...... of around 30 kHz with the sound pressure level of approximately 155 dB were introduced vertically to the GFRP surface through a cylindrical waveguide. The polar component of the surface energy was almost unchanged after the plasma treatment without ultrasonic irradiation, but drastically increased...

  18. The Healing Effect of Low-Temperature Atmospheric-Pressure Plasma in Pressure Ulcer: A Randomized Controlled Trial.

    Science.gov (United States)

    Chuangsuwanich, Apirag; Assadamongkol, Tananchai; Boonyawan, Dheerawan

    2016-08-31

    Pressure ulcers are difficult to treat. Recent reports of low-temperature atmospheric-pressure plasma (LTAPP) indicated its safe and effectiveness in chronic wound care management. It has been shown both in vitro and vivo studies that LTAPP not only helps facilitate wound healing but also has antimicrobial efficacy due to its composition of ion and electron, free radicals, and ultraviolet ray. We studied the beneficial effect of LTAPP specifically on pressure ulcers. In a prospective randomized study, 50 patients with pressure ulcers were divided into 2 groups: Control group received standard wound care and the study group was treated with LTAPP once every week for 8 consecutive weeks in addition to standard wound care. We found that the group treated with LTAPP had significantly better PUSH (Pressure Ulcer Scale for Healing) scores and exudate amount after 1 week of treatment. There was also a reduction in bacterial load after 1 treatment regardless of the species of bacteria identified.

  19. The effect of seed electrons on the repeatability of atmospheric pressure plasma plume propagation: I. Experiment

    Science.gov (United States)

    Nie, L.; Chang, L.; Xian, Y.; Lu, X.

    2016-09-01

    One of the significant differences between the traditional streamers and the plasma jets is the repeatability of their propagation. In this paper, the effect of the seed electron density on the repeatability of the plasma jets is investigated. The seed electron density plays an essential role in the propagation of plasma plume which is in either repeatable mode or random mode depending on the frequency of the applied voltage and the mixture percentage of the working gas. By measuring the propagation velocities and the ignition delay time, it is found that the propagation velocities of the plasma plume are independent of the seed electron density. However, the jitter of the ignition delay time strongly depends on the frequency of the applied voltage and the mixture percentage of the working gas. After detailed analyzing of the experiment results, it is concluded that the minimum seed electron density required for the plasma bullet to propagate in repeatable mode is on the order of 108 cm-3 for gas pressure of 2 × 104 Pa. The minimum required seed electron density for the gas pressure of 4 × 103 Pa is on the order of 107 cm-3. Further analysis shows that, at one atmospheric pressure, the required minimum seed electron density for repeatable mode is on the order of 109 cm-3.

  20. Atomic oxygen behavior at downstream of AC excited atmospheric pressure He plasma jet

    Science.gov (United States)

    Takeda, Keigo; Ishikawa, Kenji; Tanaka, Hiromasa; Sekine, Makoto; Hori, Masaru

    2016-09-01

    Applications of atmospheric pressure plasma jets (APPJ) have been investigated in the plasma medical fields such as cancer therapy, blood coagulation, etc. Reactive species generated by the plasma jet interacts with the biological surface. Therefore, the issue attracts much attentions to investigate the plasma effects on targets. In our group, a spot-size AC excited He APPJ have been used for the plasma medicine. From diagnostics of the APPJ using optical emission spectroscopy, the gas temperature and the electron density was estimated to be 299 K and 3.4 ×1015 cm-3. The AC excited He APPJ which affords high density plasma at room temperature is considered to be a powerful tool for the medical applications. In this study, by using vacuum ultraviolet absorption spectroscopy, the density of atomic oxygen on a floating copper as a target irradiated by the He APPJ was measured as a function of the distance between the plasma source and the copper wire. The measured density became a maximum value around 8 ×1013 cm-3 at 12 mm distance, and then decreased over the distance. It is considered that the behavior was due to the changes in the plasma density on the copper wire and influence of ambient air.

  1. Effect of atmospheric pressure plasma treatment condition on adhesion of ramie fibers to polypropylene for composite

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ying [College of Material and Textile Engineering, Jiaxing University, Jiaxing 314033 (China); Center for Plasma-Aided Manufacturing, Madison, WI 53706 (United States); School of Human Ecology, University of Wisconsin-Madison, Madison, WI 53706 (United States); Manolache, Sorin [Center for Plasma-Aided Manufacturing, Madison, WI 53706 (United States); US Forest Products Laboratory, Madison, WI 53726 (United States); Qiu, Yiping, E-mail: ypqiu@dhu.edu.cn [College of Textiles, Donghua University, Shanghai 201620 (China); Sarmadi, Majid, E-mail: majidsar@wisc.edu [Center for Plasma-Aided Manufacturing, Madison, WI 53706 (United States); School of Human Ecology, University of Wisconsin-Madison, Madison, WI 53706 (United States); Materials Science Program, University of Wisconsin-Madison, Madison, WI 53706 (United States)

    2016-02-28

    Graphical abstract: - Highlights: • The continuous ethanol flow technique can successfully modify ramie fiber surface with an increase in IFSS value up to 50%. • Response surface methodology was applied to design the plasma treatment parameters for ramie fiber modification. • The ethanol flow rate was the most influential treatment parameter in plasma modification process. - Abstract: In order to improve the interfacial adhesion between hydrophilic ramie fibers and hydrophobic polypropylene (PP) matrices, ramie fibers are modified by atmospheric pressure dielectric barrier discharge (DBD) plasma with our continuous ethanol flow technique in helium environment. A central composite design of experiments with different plasma processing parameter combinations (treatment current, treatment time and ethanol flow rate) is applied to find the most influential parameter and to obtain the best modification effect. Field emission scanning electron microscope (SEM) shows the roughened surfaces of ramie fibers from the treated groups due to plasma etching effect. Dynamic contact angle analysis (DCAA) demonstrates that the wettability of the treated fibers drastically decreases. Microbond pullout test shows that the interfacial shear strength (IFSS) between treated ramie fibers and PP matrices increases significantly. Residual gas analysis (RGA) confirms the creation of ethyl groups during plasma treatment. This study shows that our continuous ethanol flow technique is effective in the plasma modification process, during which the ethanol flow rate is the most influential parameter but all parameters have simultaneous influence on plasma modification effect of ramie fibers.

  2. Characterizations of atmospheric pressure low temperature plasma jets and their applications

    Science.gov (United States)

    Karakas, Erdinc

    2011-12-01

    Atmospheric pressure low temperature plasma jets (APLTPJs) driven by short pulses have recently received great attention because of their potential in biomedical and environmental applications. This potential is due to their user-friendly features, such as low temperature, low risk of arcing, operation at atmospheric pressure, easy handheld operation, and low concentration of ozone generation. Recent experimental observations indicate that an ionization wave exists and propagates along the plasma jet. The plasma jet created by this ionization wave is not a continuous medium but rather consists of a bullet-like-structure known as "Plasma Bullet". More interestingly, these plasma bullets actually have a donut-shaped makeup. The nature of the plasma bullet is especially interesting because it propagates in the ambient air at supersonic velocities without any externally applied electric field. In this dissertation, experimental insights are reported regarding the physical and chemical characteristics of the APLTPJs. The dynamics of the plasma bullet are investigated by means of a high-speed ICCD camera. A plasma bullet propagation model based on the streamer theory is confirmed with adequate explanations. It is also found that a secondary discharge, ignited by the charge accumulation on the dielectric electrode surfaces at the end of the applied voltage, interrupts the plasma bullet propagation due to an opposing current along the ionization channel. The reason for this interesting phenomenon is explained in detail. The plasma bullet comes to an end when the helium mole fraction along the ionization channel, or applied voltage, or both, are less than some critical values. The presence of an inert gas channel in the surrounding air, such as helium or argon, has a critical role in plasma bullet formation and propagation. For this reason, a fluid dynamics study is employed by a commercially available simulation software, COMSOL, based on finite element method. Spatio

  3. Atmospheric pressure plasma CVD as a tool to functionalise wound dressings.

    Science.gov (United States)

    Spange, Sebastian; Pfuch, Andreas; Wiegand, Cornelia; Beier, Oliver; Hipler, Uta C; Grünler, Bernd

    2015-02-01

    The main goal of this investigation was the preparation of an antibacterial layer system for additional modification of wound dressings with atmospheric plasma. Furthermore, the modified wound dressings were checked on there bactericidal and cytotoxic activity. The layer system was applied by using a novel atmospheric pressure plasma chemical vapour deposition technique on a variety of textile substrates which are suitable as wound dressing materials. The layer system composed of silicon dioxide with in situ generated embedded silver nanoparticles. The bactericidal activity of the produced wound dressings was investigated against different bacteria like Staphylococcus aureus and Klebsiella pneumoniae while the cytotoxic potential of the coated wound dressings was verified using human keratinocytes. Even at low concentrations of silver precursor a strong antibacterial effect was observed in direct contact with S. aureus and K. pneumoniae. Furthermore, extractions produced from the coated textiles showed a good antibacterial effect. By means of optimised coating parameters a therapeutic window for those wound dressings could be identified. Consequently, the atmospheric pressure plasma chemical vapour deposition technique promise an effective and low cost modification of wound dressing materials.

  4. 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.

  5. Atmospheric pressure plasma polymers for tuned QCM detection of protein adhesion.

    Science.gov (United States)

    Rusu, G B; Asandulesa, M; Topala, I; Pohoata, V; Dumitrascu, N; Barboiu, M

    2014-03-15

    Our efforts have been concentrated in preparing plasma polymeric thin layers at atmospheric pressure grown on Quartz Crystal Microbalance-QCM electrodes for which the non-specific absorption of proteins can be efficiently modulated, tuned and used for QCM biosensing and quantification. Plasma polymerization reaction at atmospheric pressure has been used as a simple and viable method for the preparation of QCM bioactive surfaces, featuring variable protein binding properties. Polyethyleneglycol (ppEG), polystyrene (ppST) and poly(ethyleneglycol-styrene) (ppST-EG) thin-layers have been grown on QCM electrodes. These layers were characterized by Atomic Force Microscopy (AFM), Contact angle measurements, Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The plasma ppST QCM electrodes present a higher adsorption of Concanavalin A (ConA) and Bovine Serum Albumin (BSA) proteins when compared with the commercial coated polystyrene (ppST) ones. The minimum adsorption was found for ppEG, surface, known by their protein anti-fouling properties. The amount of adsorbed proteins can be tuned by the introduction of PEG precursors in the plasma discharge during the preparation of ppST polymers.

  6. Controlling the nitric and nitrous oxide production of an atmospheric pressure plasma jet

    Science.gov (United States)

    Douat, Claire; Hubner, Simon; Engeln, Richard; Benedikt, Jan

    2016-09-01

    Atmospheric pressure plasma jets are non-thermal plasmas and have the ability to create reactive species. These features make it a very attractive tool for biomedical applications. In this work, we studied NO and N2O production, which are two species having biomedical properties. NO plays a role in the vascularization and in ulcer treatment, while N2O is used as anesthetic and analgesic gas. In this study, the plasma source is similar to the COST Reference Microplasma Jet (µ-APPJ). Helium is used as feed gas with small admixtures of molecular nitrogen and oxygen of below 1%. The absolute densities of NO and N2O were measured in the effluent of an atmospheric pressure RF plasma jet by means of ex-situ quantum-cascade laser absorption spectroscopy via a multi-pass cell in Herriot configuration. We will show that the species' production is dependent on several parameters such as power, flow and oxygen and nitrogen admixture. The NO and N2O densities are strongly dependent on the N2-O2 ratio. Changing this ratio allows for choosing between a NO-rich or a N2O-rich regime.

  7. Diffuse plasma treatment of polyamide 66 fabric in atmospheric pressure air

    Science.gov (United States)

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

    2016-01-01

    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.

  8. Mechanisms behind surface modification of polypropylene film using an atmospheric-pressure plasma jet

    Science.gov (United States)

    Shaw, David; West, Andrew; Bredin, Jerome; Wagenaars, Erik

    2016-12-01

    Plasma treatments are common for increasing the surface energy of plastics, such as polypropylene (PP), to create improved adhesive properties. Despite the significant differences in plasma sources and plasma properties used, similar effects on the plastic film can be achieved, suggesting a common dominant plasma constituent and underpinning mechanism. However, many details of this process are still unknown. Here we present a study into the mechanisms underpinning surface energy increase of PP using atmospheric-pressure plasmas. For this we use the effluent of an atmospheric-pressure plasma jet (APPJ) since, unlike most plasma sources used for these treatments, there is no direct contact between the plasma and the PP surface; the APPJ provides a neutral, radical-rich environment without charged particles and electric fields impinging on the PP surface. The APPJ is a RF-driven plasma operating in helium gas with small admixtures of O2 (0-1%), where the effluent propagates through open air towards the PP surface. Despite the lack of charged particles and electric fields on the PP surface, measurements of contact angle show a decrease from 93.9° to 70.1° in 1.4 s and to 35° in 120 s, corresponding to a rapid increase in surface energy from 36.4 mN m-1 to 66.5 mN m-1 in the short time of 1.4 s. These treatment effects are very similar to what is found in other devices, highlighting the importance of neutral radicals produced by the plasma. Furthermore, we find an optimum percentage of oxygen of 0.5% within the helium input gas, and a decrease of the treatment effect with distance between the APPJ and the PP surface. These observed effects are linked to two-photon absorption laser-induced fluorescence spectroscopy (TALIF) measurements of atomic oxygen density within the APPJ effluent which show similar trends, implying the importance of this radical in the surface treatment of PP. Analysis of the surface reveals a two stage mechanism for the production of polar

  9. Simulation Tool for Dielectric Barrier Discharge Plasma Actuators at Atmospheric and Sub-Atmospheric Pressures: SBIR Phase I Final Report

    Science.gov (United States)

    Likhanskii, Alexandre

    2012-01-01

    This report is the final report of a SBIR Phase I project. It is identical to the final report submitted, after some proprietary information of administrative nature has been removed. The development of a numerical simulation tool for dielectric barrier discharge (DBD) plasma actuator is reported. The objectives of the project were to analyze and predict DBD operation at wide range of ambient gas pressures. It overcomes the limitations of traditional DBD codes which are limited to low-speed applications and have weak prediction capabilities. The software tool allows DBD actuator analysis and prediction for subsonic to hypersonic flow regime. The simulation tool is based on the VORPAL code developed by Tech-X Corporation. VORPAL's capability of modeling DBD plasma actuator at low pressures (0.1 to 10 torr) using kinetic plasma modeling approach, and at moderate to atmospheric pressures (1 to 10 atm) using hydrodynamic plasma modeling approach, were demonstrated. In addition, results of experiments with pulsed+bias DBD configuration that were performed for validation purposes are reported.

  10. Surface modification of acrylate intraocular lenses with dielectric barrier discharge plasma at atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    WANG Yao; LIU ZhenMei; XU ZhiKang; YAO Ke

    2009-01-01

    Surface modification with dielectric barrier discharge (DBD) plasma was carried out at atmospheric pressure (argon as the discharge gas) to improve the biocompatibility of hydrophobic acrylate intraocular lens (IOL). Changes of the plasma-treated IOL surface in chemical composition,morphology and hydrophilicity were comprehensively evaluated by X-ray photoelectron spectroscopy (XPS),field emission scanning electron microscopy (FESEM),atomic force microscopy (AFM) and water contact angle (WCA) measurements. The surface biocompatibility of the untreated and plasma-treated IOLs was compared with the adhesion behavior of platelets,macrophages and lens epithelial cells (LECs) in vitro. After DBD plasma treatment,the hydrophilicity of the IOL surface was obviously improved. The changes in WCA with treatment extension may be attributed to both the introduction of oxygen or/and nitrogen-containing polar groups and the increase of surface roughness induced by plasma etching effect. The existence of low molecular weight oxidized material (LMWOM) was proved on the plasma treated IOL which was caused by the chain scission effect of the plasma treatment. The plasma-treated lOLs resisted the adhesion of platelets and macrophages significantly. The LECs spreading and proliferation were postponed on the lOLs plasma-treated for more than 180 s,with a well maintained epithelial phenotype of LECs. The IOL biocompatibility was improved after the DBD plasma treatment. We speculate that slighter foreign-body reaction and later incidence of anterior capsule opacification (ACO) may be expected after implantation of the argon DBD plasma-treated IOL.

  11. Surface modification of acrylate intraocular lenses with dielectric barrier discharge plasma at atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Surface modification with dielectric barrier discharge(DBD) plasma was carried out at atmospheric pressure(argon as the discharge gas) to improve the biocompatibility of hydrophobic acrylate intraocular lens(IOL).Changes of the plasma-treated IOL surface in chemical composition,morphology and hydrophilicity were comprehensively evaluated by X-ray photoelectron spectroscopy(XPS),field emission scanning electron microscopy(FESEM),atomic force microscopy(AFM) and water contact angle(WCA) measurements.The surface biocompatibility of the untreated and plasma-treated IOLs was compared with the adhesion behavior of platelets,macrophages and lens epithelial cells(LECs) in vitro.After DBD plasma treatment,the hydrophilicity of the IOL surface was obviously improved.The changes in WCA with treatment extension may be attributed to both the introduction of oxygen or/and nitrogen-containing polar groups and the increase of surface roughness induced by plasma etching effect.The existence of low molecular weight oxidized material(LMWOM) was proved on the plasma-treated IOL which was caused by the chain scission effect of the plasma treatment.The plasma-treated IOLs resisted the adhesion of platelets and macrophages significantly.The LECs spreading and proliferation were postponed on the IOLs plasma-treated for more than 180 s,with a well maintained epithelial phenotype of LECs.The IOL biocompatibility was improved after the DBD plasma treatment.We speculate that slighter foreign-body reaction and later incidence of anterior capsule opacification(ACO) may be expected after implantation of the argon DBD plasma-treated IOL.

  12. Atmospheric pressure resistive barrier air plasma jet induced bacterial inactivation in aqueous environment

    Science.gov (United States)

    Thiyagarajan, Magesh; Sarani, Abdollah; Gonzales, Xavier

    2013-03-01

    An atmospheric pressure resistive barrier air plasma jet is designed to inactivate bacteria in aqueous media in direct and indirect exposure modes of treatment. The resistive barrier plasma jet is designed to operate at both dc and standard 50-60 Hz low frequency ac power input and the ambient air at 50% humidity level was used as the operating gas. The voltage-current characteristics of the plasma jet were analyzed and the operating frequency of the discharge was measured to be 20 kHz and the plasma power was measured to be 26 W. The plasma jet rotational temperatures (Trot) are obtained from the optical emission spectra, from the N2C-B(2+) transitions by matching the experimental spectrum results with the Spectra Air (SPECAIR) simulation spectra. The reactive oxygen and nitrogen species were measured using optical emission spectroscopy and gas analyzers, for direct and indirect treatment modes. The nitric oxides (NO) were observed to be the predominant long lived reactive nitrogen species produced by the plasma. Three different bacteria including Staphylococcus aureus (Gram-positive), Escherichia coli (Gram-negative), and Neisseria meningitidis (Gram-negative) were suspended in an aqueous media and treated by the resistive barrier air plasma jet in direct and indirect exposure modes. The results show that a near complete bacterial inactivation was achieved within 120 s for both direct and indirect plasma treatment of S. aureus and E. coli bacteria. Conversely, a partial inactivation of N. meningitidis was observed by 120 s direct plasma exposure and insignificant inactivation was observed for the indirect plasma exposure treatment. Plasma induced shifts in N. meningitidis gene expression was analyzed using pilC gene expression as a representative gene and the results showed a reduction in the expression of the pilC gene compared to untreated samples suggesting that the observed protection against NO may be regulated by other genes.

  13. Characterization of an atmospheric pressure plasma jet and its applications for disinfection and cancer treatment.

    Science.gov (United States)

    Thiyagarajan, Magesh; Sarani, Abdollah; Gonzales, Xavier F

    2013-01-01

    In this work an atmospheric pressure non-thermal resistive barrier (RB) plasma jet was constructed, characterized and was applied for biomedical applications. The RB plasma source can operate in both DC (battery) as well as in standard 60/50 Hz low frequency AC excitation, and it functions effectively in both direct and indirect plasma exposure configurations. The characteristics of the RB plasma jet such as electrical properties, plasma gas temperature and nitric oxides concentration were determined using voltage-current characterization, optical emission spectroscopy and gas analyzer diagnostic techniques. Plasma discharge power of 26.33 W was calculated from voltage-current characterization. An optical emission spectroscopy was applied and the gas temperature which is equivalent to the nitrogen rotational (Trot) temperatures was measured. The concentrations of the reactive oxygen species at different spatial distances from the tip of the plasma jet were measured and the ppm concentration of NO is at the preferred level for a wide range of standard biomedical treatment applications. The ppm values of nitric oxides after the cooling unit are observed to be of the same order of magnitude as compared to plasma jet. The portable RB plasma source was tested to be very effective for decontamination and disinfection of a wide range of foodborne and opportunistic nosocomial pathogens such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus cereus and the preliminary results are presented. The effects of indirect exposure of the portable RBP source on monocytic leukemia cancer cells (THP-1) were also tested and the results demonstrate that a preference for apoptosis in plasma treated THP-1 cells under particular plasma parameters and dosage levels.

  14. Propagation characteristics of atmospheric-pressure He+O2 plasmas inside a simulated endoscope channel

    Science.gov (United States)

    Wang, S.; Chen, Z. Y.; Wang, X. H.; Li, D.; Yang, A. J.; Liu, D. X.; Rong, M. Z.; Chen, H. L.; Kong, M. G.

    2015-11-01

    Cold atmospheric-pressure plasmas have potential to be used for endoscope sterilization. In this study, a long quartz tube was used as the simulated endoscope channel, and an array of electrodes was warped one by one along the tube. Plasmas were generated in the inner channel of the tube, and their propagation characteristics in He+O2 feedstock gases were studied as a function of the oxygen concentration. It is found that each of the plasmas originates at the edge of an instantaneous cathode, and then it propagates bidirectionally. Interestingly, a plasma head with bright spots is formed in the hollow instantaneous cathode and moves towards its center part, and a plasma tail expands through the electrode gap and then forms a swallow tail in the instantaneous anode. The plasmas are in good axisymmetry when [O2] ≤ 0.3%, but not for [O2] ≥ 1%, and even behave in a stochastic manner when [O2] = 3%. The antibacterial agents are charged species and reactive oxygen species, so their wall fluxes represent the "plasma dosage" for the sterilization. Such fluxes mainly act on the inner wall in the hollow electrode rather than that in the electrode gap, and they get to the maximum efficiency when the oxygen concentration is around 0.3%. It is estimated that one can reduce the electrode gap and enlarge the electrode width to achieve more homogenous and efficient antibacterial effect, which have benefits for sterilization applications.

  15. Gene Transfection Method Using Atmospheric Pressure Dielectric-Barrier Discharge Plasmas

    Science.gov (United States)

    Sasaki, Shota; Kanzaki, Makoto; Kaneko, Toshiro

    2013-09-01

    Gene transfection which is the process of deliberately introducing nucleic acids into cells is expected to play an important role in medical treatment because the process is necessary for gene therapy and creation of induced pluripotent stem (iPS) cells. However, the conventional transfection methods have some problems, so we focus attention on promising transfection methods by atmospheric pressure dielectric-barrier discharge (AP-DBD) plasmas. AP-DBD He plasmas are irradiated to the living cell covered with genes. Preliminarily, we use fluorescent dye YOYO-1 instead of the genes and use LIVE/DEAD Stain for cell viability test, and we analyze the transfection efficiency and cell viability under the various conditions. It is clarified that the transfection efficiency is strongly dependence on the plasma irradiation time and cell viability rates is high rates (>90%) regardless of long plasma irradiation time. These results suggest that ROS (Reactive Oxygen Species) and electric field generated by the plasma affect the gene transfection. In addition to this (the plasma irradiation time) dependency, we now investigate the effect of the plasma irradiation under the various conditions.

  16. Atmospheric pressure plasma jets interacting with liquid covered tissue: touching and not-touching the liquid

    Science.gov (United States)

    Norberg, Seth A.; Tian, Wei; Johnsen, Eric; Kushner, Mark J.

    2014-11-01

    In the use of atmospheric pressure plasma jets in biological applications, the plasma-produced charged and neutral species in the plume of the jet often interact with a thin layer of liquid covering the tissue being treated. The plasma-produced reactivity must then penetrate through the liquid layer to reach the tissue. In this computational investigation, a plasma jet created by a single discharge pulse at three different voltages was directed onto a 200 µm water layer covering tissue followed by a 10 s afterglow. The magnitude of the voltage and its pulse length determined if the ionization wave producing the plasma plume reached the surface of the liquid. When the ionization wave touches the surface, significantly more charged species were created in the water layer with H3O+aq, O3-aq, and O2-aq being the dominant terminal species. More aqueous OHaq, H2O2aq, and O3aq were also formed when the plasma plume touches the surface. The single pulse examined here corresponds to a low repetition rate plasma jet where reactive species would be blown out of the volume between pulses and there is not recirculation of flow or turbulence. For these conditions, NxOy species do not accumulate in the volume. As a result, aqueous nitrites, nitrates, and peroxynitrite, and the HNO3aq and HOONOaq, which trace their origin to solvated NxOy, have low densities.

  17. Measurements of Rotational Temperatures in Atmospheric-Pressure Capillary Plasma Electrode (CPE) Discharge

    Science.gov (United States)

    Figus, Margaret; Abramzon, Nina; Becker, Kurt

    2003-10-01

    We report the results of rotational temperature measurements in atmospheric-pressure capillary plasma electrode (CPE) discharges in ambient air using the unresolved N2 second positive band. Assuming that the emitting N2 molecules can be described by a Maxwell-Boltzmann distribution characterized by a single rotational temperature, this temperature is determined from a fit of the measured emission spectrum to a calculated spectrum. If the emitting species are in equilibrium with the bulk gas in the plasma, then this temperature can be interpreted as the gas kinetic temperature in the plasma. We determined rotational temperatures for three different plasma regions: inside the capillary by analyzing radiation emitted along the axis of the capillary, between the capillaries, and perpendicular to the axis of the capillary. Each region has a different plasma density and, therefore, a different gas temperature with the plasma inside the capillary being the hottest. We also measured the rotational temperatures in each region as a function of the plasma power. As expected, the rotational temperatures increase with increasing discharge power. Work supported by the NSF and by ARO through a DURIP award.

  18. Numerical study of the interaction of a helium atmospheric pressure plasma jet with a dielectric material

    Science.gov (United States)

    Wang, Lijun; Zheng, Yashuang; Jia, Shenli

    2016-10-01

    This is a computational modeling study of a cold atmospheric pressure helium plasma jet impinging on a dielectric surface placed normal to the jet axis. This study provides insights into the propagation mechanism of the plasma jet, the electrical properties, and the total accumulated charge density at the dielectric surface. For the radial streamer propagation along the dielectric surface, Penning ionization and the electron impact ionization of helium atoms are the major ionization reactions in the streamer head, while Penning ionization is the only dominant contributor along the streamer body. In addition, the plasma bullet velocity along the dielectric surface is 10-100 times lower than that in the plasma column. Increasing tube radius or helium flow rate lowers air entrainment in the plasma jet, leading to a decrease of the radial electric field and the accumulated charge density at the dielectric surface. Furthermore, the tube radius has weaker influence on the plasma properties as tube radius increases. For a target dielectric with lower relative permittivity, a higher radial electric field penetrates into the material, and the surface ionization wave along the dielectric surface extends farther. Higher relative permittivity of the treated dielectric results in more charging at the dielectric surface and more electron density in the plasma column.

  19. Atmospheric pressure plasma polymerization using double grounded electrodes with He/Ar mixture

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Ha; Kim, Hyun-Jin; Park, Choon-Sang; Tae, Heung-Sik, E-mail: hstae@ee.knu.ac.kr [School of Electronics Engineering, College of IT Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); Shin, Bhum Jae [Department of Electronics Engineering, Sejong University, Seoul 143-747 (Korea, Republic of); Seo, Jeong Hyun [Department of Electronics Engineering, Incheon National University, Incheon 406-772 (Korea, Republic of)

    2015-09-15

    In this study, we have proposed the double grounded atmospheric pressure plasma jet (2G-APPJ) device to individually control the plasmas in both fragmentation (or active) and recombination (or passive) regions with a mixture of He and Ar gases to deposit organic thin films on glass or Si substrates. Plasma polymerization of acetone has been successfully deposited using a highly energetic and high-density 2G-APPJ and confirmed by scanning electron microscopy (SEM). Plasma composition was measured by optical emission spectroscopy (OES). In addition to a large number of Ar and He spectra lines, we observed some spectra of C{sub 2} and CH species for fragmentation and N{sub 2} (second positive band) species for recombination. The experimental results confirm that the Ar gas is identified as a key factor for facilitating fragmentation of acetone, whereas the He gas helps the plume of plasma reach the substrate on the 2{sup nd} grounded electrode during the plasma polymerization process. The high quality plasma polymerized thin films and nanoparticles can be obtained by the proposed 2G-APPJ device using dual gases.

  20. Atmospheric pressure plasma polymerization using double grounded electrodes with He/Ar mixture

    Directory of Open Access Journals (Sweden)

    Dong Ha Kim

    2015-09-01

    Full Text Available In this study, we have proposed the double grounded atmospheric pressure plasma jet (2G-APPJ device to individually control the plasmas in both fragmentation (or active and recombination (or passive regions with a mixture of He and Ar gases to deposit organic thin films on glass or Si substrates. Plasma polymerization of acetone has been successfully deposited using a highly energetic and high-density 2G-APPJ and confirmed by scanning electron microscopy (SEM. Plasma composition was measured by optical emission spectroscopy (OES. In addition to a large number of Ar and He spectra lines, we observed some spectra of C2 and CH species for fragmentation and N2 (second positive band species for recombination. The experimental results confirm that the Ar gas is identified as a key factor for facilitating fragmentation of acetone, whereas the He gas helps the plume of plasma reach the substrate on the 2nd grounded electrode during the plasma polymerization process. The high quality plasma polymerized thin films and nanoparticles can be obtained by the proposed 2G-APPJ device using dual gases.

  1. DNA damage in oral cancer and normal cells induced by nitrogen atmospheric pressure plasma jets

    Science.gov (United States)

    Han, Xu; Kapaldo, James; Liu, Yueying; Stack, M. Sharon; Ptasinska, Sylwia

    2015-09-01

    Nitrogen atmospheric pressure plasma jets (APPJs) have been shown to effectively induce DNA double strand breaks in SCC25 oral cancer cells. The APPJ source constructed in our laboratory operates based on dielectric barrier discharge. It consists of two copper electrodes alternatively wrapping around a fused silica tube with nitrogen as a feed gas. It is generally more challenging to ignite plasma in N2 atmosphere than in noble gases. However, N2 provides additional advantages such as lower costs compared to noble gases, thus this design can be beneficial for the future long-term clinical use. To compare the effects of plasma on cancer cells (SCC25) and normal cells (OKF), the cells from both types were treated at the same experimental condition for various treatment times. The effective area with different damage levels after the treatment was visualized as 3D maps. The delayed damage effects were also explored by varying the incubation times after the treatment. All of these studies are critical for a better understanding of the damage responses of cellular systems exposed to the plasma radiation, thus are useful for the development of the advanced plasma cancer therapy. The research described herein was supported by the Division of Chemical Sciences, Geosciences and Biosciences, Basic Energy Sciences, Office of Science, United States Department of Energy through Grant No. DE-FC02-04ER15533.

  2. Study of an Atmospheric Pressure Plasma Jet of Argon Generated by Column Dielectric Barrier Discharge

    Science.gov (United States)

    Nur, M.; Kinandana, A. W.; Winarto, P.; Muhlisin, Z.; Nasrudin

    2016-11-01

    An atmospheric of argon plasma jet was generated by using column dielectric barrier discharge has been investigated. In this study, argon gas was passed through the capillary column by regulating the flow rate of gas. This atmospheric pressure plasma jet (APPJ) was generated by a sinusoidal AC high voltage in the range of 0.4 kV to 10 kV and at frequencies of 15 kHz and 26 kHz. APPJ has been produced with flow rate of argon gas from 1 litter/min - 10 litters/min. The electric current has been taken with variation of voltage and each interval argon gas flow rate of 1 litter/min. The results show that electric current increase linearly and then it trends to saturation condition by the increasing of applied voltage. We found also that the length of the plasma jet increase by augmenting of applied voltage both for frequencies of 15 kHz and 26 kHz. Furthermore, our results show that length of plasma jet optimum for flow rate of argon gas of 2 litters/minute. In addition, we obtained that the larger applied voltage, the greater the temperature of the plasma jet.

  3. Atmospheric Pressure non-thermal plasmas for surface treatment of polymer films

    Science.gov (United States)

    Huang, Hsiao-Feng; Wen, Chun-Hsiang; Wei, Hsiao-Kuan; Kou, Chwung-Shan

    2006-10-01

    Interest has grown over the past few years in applying atmospheric pressure non-thermal plasmas to surface treatment. In this work, we used an asymmetric glow dielectric-barrier discharge (GDBD), at atmospheric pressure in nitrogen, to improve the surface hydrophilicity of three kinds of polymer films, biaxially oriented polypropylene (BOPP), polyimide (PI), and triacetyl cellulose (TAC). This set-up consists of two asymmetric electrodes covered by dielectrics. And to prevent the filamentary discharge occur, the frequency, gas flow rate and uniformity of gas flow distribution should be carefully controlled. The discharge performance is monitored through an oscilloscope, which is connected to a high voltage probe and a current monitor. The physical and chemical properties of polymer surfaces before and after GDBD treatment were analyzed via water contact angle (CA) measurements, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) techniques.

  4. Atmospheric-pressure plasma jet characterization and applications on melanoma cancer treatment (B/16-F10)

    Science.gov (United States)

    Mashayekh, Shahriar; Rajaee, Hajar; Akhlaghi, Morteza; Shokri, Babak; Hassan, Zuhir M.

    2015-09-01

    A new approach in medicine is the use of cold plasma for various applications such as sterilization blood coagulation and cancer cell treatment. In this paper, a pin-to-hole plasma jet for biological applications has been designed and manufactured and characterized. The characterization includes power consumption via Lissajous method, thermal behavior of atmospheric-pressure plasma jet by using Infra-red camera as a novel method and using Speicair software to determine vibrational and transitional temperatures, and optical emission spectroscopy to determine the generated species. Treatment of Melanoma cancer cells (B16/F10) was also implemented, and tetrazolium salt dye (MTT assay) and flow cytometry were used to evaluate viability. Effect of ultraviolet photons on cancerous cells was also observed using an MgF2 crystal with MTT assay. Finally, in-vivo studies on C57 type mice were also done in order to have a better understanding of the effects in real conditions.

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

    Science.gov (United States)

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

    2016-06-01

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

  6. Atmospheric-pressure plasma jet characterization and applications on melanoma cancer treatment (B/16-F10)

    Energy Technology Data Exchange (ETDEWEB)

    Mashayekh, Shahriar [Physics Department, Shahid Beheshti University, G.C., Evin, 19839-63113 Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Rajaee, Hajar; Hassan, Zuhir M. [Imonology Department, Faculty of Medical Science, Tarbiat Modarres University, Tehran (Iran, Islamic Republic of); Akhlaghi, Morteza [Laser-Plasma Research Institute, Shahid Beheshti University, G.C., Evin, 19839-63113 Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Shokri, Babak [Physics Department and Laser-Plasma Research Institute, Shahid Beheshti University, G.C., Evin, 19839-63113 Tehran, Islamic Republic of Iran (Iran, Islamic Republic of)

    2015-09-15

    A new approach in medicine is the use of cold plasma for various applications such as sterilization blood coagulation and cancer cell treatment. In this paper, a pin-to-hole plasma jet for biological applications has been designed and manufactured and characterized. The characterization includes power consumption via Lissajous method, thermal behavior of atmospheric-pressure plasma jet by using Infra-red camera as a novel method and using Speicair software to determine vibrational and transitional temperatures, and optical emission spectroscopy to determine the generated species. Treatment of Melanoma cancer cells (B16/F10) was also implemented, and tetrazolium salt dye (MTT assay) and flow cytometry were used to evaluate viability. Effect of ultraviolet photons on cancerous cells was also observed using an MgF{sub 2} crystal with MTT assay. Finally, in-vivo studies on C57 type mice were also done in order to have a better understanding of the effects in real conditions.

  7. Surface modification of polyester synthetic leather with tetramethylsilane by atmospheric pressure plasma

    Science.gov (United States)

    Kan, C. W.; Kwong, C. H.; Ng, S. P.

    2015-08-01

    Much works have been done on synthetic materials but scarcely on synthetic leather owing to its surface structures in terms of porosity and roughness. This paper examines the use of atmospheric pressure plasma (APP) treatment for improving the surface performance of polyester synthetic leather by use of a precursor, tetramethylsilane (TMS). Plasma deposition is regarded as an effective, simple and single-step method with low pollution. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) confirm the deposition of organosilanes on the sample's surface. The results showed that under a particular combination of treatment parameters, a hydrophobic surface was achieved on the APP treated sample with sessile drop static contact angle of 138°. The hydrophobic surface is stable without hydrophilic recovery 30 days after plasma treatment.

  8. Adhesion improvement of fibres by continuous plasma treatment at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Kusano, Y.; Andersen, Tom L.; Soerensen, B.F.; Toftegaard, H.L.; Teodoru, S. [Technical Univ. of Denmark. DTU Wind Energy, Risoe Campus, Roskilde (Denmark); Hansen, Charles M. [Hoersholm (Denmark)

    2013-09-01

    Carbon fibres and ultra-high-molecular-weight polyethylene (UHMWPE) fibres were continuously treated by a dielectric barrier discharge plasma at atmospheric pressure for adhesion improvement with epoxy resins. The plasma treatment improved wettability, increased the oxygen containing polar functional groups at the surface, and subsequently improved adhesion to the epoxy and fracture resistance of epoxy composites. Hansen solubility parameters (HSP), quantitatively describing physical interactions among molecules, were measured for the UHMWPE fibre surfaces. The result identifies two distinct types of surfaces in both the plasma treated and the untreated fibres. One type is typical of polyethylene polymers while the other is characteristic of the oxygenated surface at much higher values of HSP. (Author)

  9. Surface modification of cellulosic substrates via atmospheric pressure plasma polymerization of acrylic acid: Structure and properties

    Science.gov (United States)

    Garcia-Torres, Jose; Sylla, Dioulde; Molina, Laura; Crespo, Eulalia; Mota, Jordi; Bautista, Llorenç

    2014-06-01

    Surface chemical modification of cellulose-based substrates has been carried out by atmospheric pressure plasma enhanced chemical vapor deposition (AP-PECVD) of acrylic acid. The structure/properties relationship of the samples was studied as a function of the plasma experimental conditions. Acrylic acid monomer/helium ratio and treatment speed clearly influences the wettability properties of the paper substrate: advancing contact angle values were reduced to the half if compare to non-treated paper. Surface morphology of the films did not greatly vary at short polymerization times but fibers were covered by a poly(acrylic acid) film at longer times. FTIR and XPS techniques allowed detecting the retention of carboxylic acid groups/moieties. The possibility to quickly design architectures with tunable carboxylic functions by modifying the plasma processing parameters is shown.

  10. Apparatus and method for atmospheric pressure reactive atom plasma processing for shaping of damage free surfaces

    Science.gov (United States)

    Carr; Jeffrey W.

    2009-03-31

    Fabrication apparatus and methods are disclosed for shaping and finishing difficult materials with no subsurface damage. The apparatus and methods use an atmospheric pressure mixed gas plasma discharge as a sub-aperture polisher of, for example, fused silica and single crystal silicon, silicon carbide and other materials. In one example, workpiece material is removed at the atomic level through reaction with fluorine atoms. In this example, these reactive species are produced by a noble gas plasma from trace constituent fluorocarbons or other fluorine containing gases added to the host argon matrix. The products of the reaction are gas phase compounds that flow from the surface of the workpiece, exposing fresh material to the etchant without condensation and redeposition on the newly created surface. The discharge provides a stable and predictable distribution of reactive species permitting the generation of a predetermined surface by translating the plasma across the workpiece along a calculated path.

  11. Disinfection of S. mutans Bacteria Using a Plasma Needle at Atmospheric Pressure

    Science.gov (United States)

    Hansen, S.; Goree, J.; Liu, Bin; Drake, D.

    2007-11-01

    The plasma needle device produces a millimeter-size low-power glow discharge at atmospheric-pressure. It is intended for dental or medical applications. Radio-frequency high voltage is applied to a single needle electrode located inside a concentric gas-flow nozzle. A low-speed helium plasma jet flows out of the nozzle and mixes with ambient air. The jet is impinges on a surface that is to be treated, which in our test was a suspension of S. mutans bacteria that was plated onto the surface of agar nutrient in a Petri dish. S. mutans is the most important microorganism for causing dental caries. Imaging the sample after plasma treatment and incubation reveal the conditions where bacteria are killed, and the size of the treated spot.

  12. Fast functionalization of multi-walled carbon nanotubes by an atmospheric pressure plasma jet.

    Science.gov (United States)

    Kolacyak, Daniel; Ihde, Jörg; Merten, Christian; Hartwig, Andreas; Lommatzsch, Uwe

    2011-07-01

    The afterglow of an atmospheric pressure plasma has been used for the fast oxidative functionalization of multi-walled carbon nanotubes (MWCNTs). Scanning electron microscopy and Raman spectroscopy demonstrate that the MWCNT morphology is mostly preserved when the MWCNTs are dispersed in a solvent and injected as a spray into the plasma. Contact angle measurements show that this approach enhances the wettability of MWCNTs and reduces their sedimentation in an aqueous dispersion. X-ray photoelectron spectroscopy, IR spectroscopy, and electrokinetic measurements show that oxygen plasma incorporates about 6.6 at.% of oxygen and creates mainly hydroxyl and carboxyl functional groups on the MWCNT surface. The typical effective treatment time is estimated to be in the range of milliseconds. The approach is ideally suited for combination with the industrial gas phase CVD synthesis of MWCNTs.

  13. Diagnostics of low and atmospheric pressure plasmas by means of mass spectrometry

    CERN Document Server

    Benedikt, Jan; von Keudell, Achim

    2011-01-01

    The knowledge of absolute fluxes of reactive species such as radicals or energetic ions to the surface is crucial for understanding the growth or etching of thin films. These species have due to their high reactivity very low densities and their detection is therefore a challenging task. Mass spectrometry is a very sensitive technique and it will be demonstrated that it is a good choice for the study of plasma chemistry. Mass spectrometry measures the plasma composition directly at the surface and is not limited by existence of accessible optical transitions. When properly designed and carefully calibrated mass spectrometry provides absolute densities of the measured species. It can even measure internally excited metastable species. Here, measurement of neutral species and positive ions generated in an atmospheric pressure plasmas jet operated with He, hexamethyldisiloxane and O2 will be presented.

  14. Modeling and simulations on the propagation characteristics of electromagnetic waves in sub-atmospheric pressure plasma slab

    Science.gov (United States)

    Wang, Z. B.; Nie, Q. Y.; Li, B. W.; Kong, F. R.

    2017-01-01

    Sub-atmospheric pressure plasma slabs exhibit the feature of relatively high plasma number density and high collisional frequency between electrons and neutral gases, as well as similar thickness to the electromagnetic (EM) wavelength in communication bands. The propagation characteristics of EM waves in sub-atmospheric pressure plasma slabs are attracting much attention of the researchers due to their applications in the plasma antenna, the blackout effect during reentry, wave energy injection in the plasma, etc. In this paper, a numerical model with a one-dimensional assumption has been established and therefore, it is used for the investigations of the propagation characteristics of the EM waves in plasma slabs. In this model, the EM waves propagating in both sub-wavelength plasma slabs and plasmas with thicker slabs can be studied simultaneously, which is superior to the model with geometrical optics approximation. The influence of EM wave frequencies and collisional frequencies on the amplitude of the transmitted EM waves is discussed in typical plasma profiles. The results will be significant for deep understanding of the propagation behaviors of the EM waves in sub-atmospheric pressure nonuniform plasma slabs, as well as the applications of the interactions between EM waves and the sub-atmospheric pressure plasmas.

  15. Eradication of Pseudomonas aeruginosa biofilms by atmospheric pressure non-thermal plasma.

    Directory of Open Access Journals (Sweden)

    Mahmoud Y Alkawareek

    Full Text Available Bacteria exist, in most environments, as complex, organised communities of sessile cells embedded within a matrix of self-produced, hydrated extracellular polymeric substances known as biofilms. Bacterial biofilms represent a ubiquitous and predominant cause of both chronic infections and infections associated with the use of indwelling medical devices such as catheters and prostheses. Such infections typically exhibit significantly enhanced tolerance to antimicrobial, biocidal and immunological challenge. This renders them difficult, sometimes impossible, to treat using conventional chemotherapeutic agents. Effective alternative approaches for prevention and eradication of biofilm associated chronic and device-associated infections are therefore urgently required. Atmospheric pressure non-thermal plasmas are gaining increasing attention as a potential approach for the eradication and control of bacterial infection and contamination. To date, however, the majority of studies have been conducted with reference to planktonic bacteria and rather less attention has been directed towards bacteria in the biofilm mode of growth. In this study, the activity of a kilohertz-driven atmospheric pressure non-thermal plasma jet, operated in a helium oxygen mixture, against Pseudomonas aeruginosa in vitro biofilms was evaluated. Pseudomonas aeruginosa biofilms exhibit marked susceptibility to exposure of the plasma jet effluent, following even relatively short (≈ 10's s exposure times. Manipulation of plasma operating conditions, for example, plasma operating frequency, had a significant effect on the bacterial inactivation rate. Survival curves exhibit a rapid decline in the number of surviving cells in the first 60 seconds followed by slower rate of cell number reduction. Excellent anti-biofilm activity of the plasma jet was also demonstrated by both confocal scanning laser microscopy and metabolism of the tetrazolium salt, XTT, a measure of bactericidal

  16. Superhydrophobic treatment using atmospheric-pressure He/C4F8 plasma for buoyancy improvement

    Science.gov (United States)

    Noh, Sooryun; Moon, A.-Young; Moon, Se Youn

    2015-04-01

    A superhydrophobic miniature boat was fabricated with aluminum alloy plates treated with atmospheric-pressure helium (He)/octafluorocyclobutane (C4F8) plasma using 13.56 MHz rf power. When only 0.13% C4F8 was added to He gas, the contact angle of the surface increased to 140° and the surface showed superhydrophobic properties. On the basis of chemical and morphological analyses, fluorinated functional groups (CF, CF2, and CF3) and nano-/micro-sized particles were detected on the Al surface. These features brought about superhydrophobicity similar to the lotus effect. While the miniature boat, assembled with plasma-treated plates, was immersed in water, a layer of air (i.e., a plastron) surrounded the superhydrophobic surfaces. This effect contributed to the development of a 4.7% increase in buoyancy. In addition, the superhydrophobic properties lasted for two months under the submerged condition. These results demonstrate that treatment with atmospheric-pressure He/C4F8 plasma is a promising method of improving the load capacity and antifouling properties, and reducing the friction of marine ships through a fast and low-cost superhydrophobic treatment process.

  17. Effects of a Nonthermal Atmospheric Pressure Plasma Jet on Human Gingival Fibroblasts for Biomedical Application

    Directory of Open Access Journals (Sweden)

    Jung-Hwan Lee

    2016-01-01

    Full Text Available Nonthermal atmospheric pressure plasma jets (APPJ have been developed and applied in biomedical research as a cancer treatment or bacterial sterilization. However, the drawback of APPJ on normal oral cells during plasma treatment and underlying cell death mechanisms have not been studied and clearly explained, although there is known to be an influence from reactive oxygen species (ROS. Hence, this study investigates whether and how a nonthermal atmospheric pressure air plasma jet kills human normal gingival cells using immortalized human gingival fibroblasts (hTERT-hNOF cells. In this study, a set of physicochemical or biological methods were used to illuminate the killing mechanisms. It was found that ROS were induced intracellularly without a breakdown of the cell wall and apoptosis was involved in cell death when an air APPJ treatment was performed on the cells directly without media; the air treatment only supported a detachment of the cells without increase of ROS. It was also revealed that a correlation between intracellular ROS concentration and cells viability existed. These results indicated that the direct air APPJ treatment possibly raises safety issue to normal tissue and thereby APPJ application in biomedical field needs more in vitro and in vivo study to optimize it.

  18. LIF diagnostics of hydroxyl radical in a methanol containing atmospheric-pressure plasma jet

    Science.gov (United States)

    Qian, Mu-Yang; Liu, San-Qiu; Pei, Xue-Kai; Lu, Xin-Pei; Zhang, Jia-Liang; Wang, De-Zhen

    2016-10-01

    In this paper, a pulsed-dc CH3OH/Ar plasma jet generated at atmospheric pressure is studied by laser-induced fluorescence (LIF) and optical emission spectroscopy (OES). A gas-liquid bubbler system is proposed to introduce the methanol vapor into the argon gas, and the CH3OH/Ar volume ratio is kept constant at about 0.1%. Discharge occurs in a 6-mm needle-to-ring gap in an atmospheric-pressure CH3OH/Ar mixture. The space-resolved distributions of OH LIF inside and outside the nozzle exhibit distinctly different behaviors. And, different production mechanisms of OH radicals in the needle-to-ring discharge gap and afterglow of plasma jet are discussed. Besides, the optical emission lines of carbonaceous species, such as CH, CN, and C2 radicals, are identified in the CH3OH/Ar plasma jet. Finally, the influences of operating parameters (applied voltage magnitude, pulse frequency, pulsewidth) on the OH radical density are also presented and analyzed. Project supported by the National Natural Science Foundation of China (Grant Nos. 11465013 and 11375041), the Natural Science Foundation of Jiangxi Province, China (Grant Nos. 20151BAB212012 and 20161BAB201013), and the International Science and Technology Cooperation Program of China (Grant No. 2015DFA61800).

  19. Novel focal point multipass cell for absorption spectroscopy on small sized atmospheric pressure plasmas.

    Science.gov (United States)

    Winter, Jörn; Hänel, Mattis; Reuter, Stephan

    2016-04-01

    A novel focal point multipass cell (FPMPC) was developed, in which all laser beams propagate through a common focal point. It is exclusively constructed from standard optical elements. Main functional elements are two 90(∘) off-axis parabolic mirrors and two retroreflectors. Up to 17 laser passes are demonstrated with a near-infrared laser beam. The number of laser passes is precisely adjustable by changing the retroreflector distance. At the focal point beams are constricted to fit through an aperture of 0.8 mm. This is shown for 11 beam passes. Moreover, the fast temporal response of the cell permits investigation of transient processes with frequencies up to 10 MHz. In order to demonstrate the applicability of the FPMPC for atmospheric pressure plasma jets, laser absorption spectroscopy on the lowest excited argon state (1s5) was performed on a 1 MHz argon atmospheric pressure plasma jet. From the obtained optical depth profiles, the signal-to-noise ratio was deduced. It is shown that an elevation of the laser pass number results in an proportional increase of the signal-to-noise ratio making the FPMPC an appropriate tool for absorption spectroscopy on plasmas of small dimensions.

  20. Novel focal point multipass cell for absorption spectroscopy on small sized atmospheric pressure plasmas

    Science.gov (United States)

    Winter, Jörn; Hänel, Mattis; Reuter, Stephan

    2016-04-01

    A novel focal point multipass cell (FPMPC) was developed, in which all laser beams propagate through a common focal point. It is exclusively constructed from standard optical elements. Main functional elements are two 90∘ off-axis parabolic mirrors and two retroreflectors. Up to 17 laser passes are demonstrated with a near-infrared laser beam. The number of laser passes is precisely adjustable by changing the retroreflector distance. At the focal point beams are constricted to fit through an aperture of 0.8 mm. This is shown for 11 beam passes. Moreover, the fast temporal response of the cell permits investigation of transient processes with frequencies up to 10 MHz. In order to demonstrate the applicability of the FPMPC for atmospheric pressure plasma jets, laser absorption spectroscopy on the lowest excited argon state (1s5) was performed on a 1 MHz argon atmospheric pressure plasma jet. From the obtained optical depth profiles, the signal-to-noise ratio was deduced. It is shown that an elevation of the laser pass number results in an proportional increase of the signal-to-noise ratio making the FPMPC an appropriate tool for absorption spectroscopy on plasmas of small dimensions.

  1. Effects of a Nonthermal Atmospheric Pressure Plasma Jet on Human Gingival Fibroblasts for Biomedical Application.

    Science.gov (United States)

    Lee, Jung-Hwan; Kim, Kyoung-Nam

    2016-01-01

    Nonthermal atmospheric pressure plasma jets (APPJ) have been developed and applied in biomedical research as a cancer treatment or bacterial sterilization. However, the drawback of APPJ on normal oral cells during plasma treatment and underlying cell death mechanisms have not been studied and clearly explained, although there is known to be an influence from reactive oxygen species (ROS). Hence, this study investigates whether and how a nonthermal atmospheric pressure air plasma jet kills human normal gingival cells using immortalized human gingival fibroblasts (hTERT-hNOF cells). In this study, a set of physicochemical or biological methods were used to illuminate the killing mechanisms. It was found that ROS were induced intracellularly without a breakdown of the cell wall and apoptosis was involved in cell death when an air APPJ treatment was performed on the cells directly without media; the air treatment only supported a detachment of the cells without increase of ROS. It was also revealed that a correlation between intracellular ROS concentration and cells viability existed. These results indicated that the direct air APPJ treatment possibly raises safety issue to normal tissue and thereby APPJ application in biomedical field needs more in vitro and in vivo study to optimize it.

  2. Surface treatment of a titanium implant using low temperature atmospheric pressure plasmas

    Science.gov (United States)

    Lee, Hyun-Young; Tang, Tianyu; Ok, Jung-Woo; Kim, Dong-Hyun; Lee, Ho-Jun; Lee, Hae June

    2015-09-01

    During the last two decades, atmospheric pressure plasmas(APP) are widely used in diverse fields of biomedical applications, reduction of pollutants, and surface treatment of materials. Applications of APP to titanium surface of dental implants is steadily increasing as it renders surfaces wettability and modifies the oxide layer of titanium that hinders the interaction with cells and proteins. In this study, we have treated the titanium surfaces of screw-shaped implant samples using a plasma jet which is composed of a ceramic coaxial tube of dielectrics, a stainless steel inner electrode, and a coper tube outer electrode. The plasma ignition occurred with Ar gas flow between two coaxial metal electrodes and a sinusoidal bias voltage of 3 kV with a frequency of 20 kHz. Titanium materials used in this study are screw-shaped implants of which diameter and length are 5 mm and 13 mm, respectively. Samples were mounted at a distance of 5 mm below the plasma source, and the plasma treatment time was set to 3 min. The wettability of titanium surface was measured by the moving speed of water on its surface, which is enhanced by plasma treatment. The surface roughness was also measured by atomic force microscopy. The optimal condition for wettability change is discussed.

  3. Reduction in lateral lipid mobility of lipid bilayer membrane by atmospheric pressure plasma irradiation

    Science.gov (United States)

    Suda, Yoshiyuki; Tero, Ryugo; Yamashita, Ryuma; Yusa, Kota; Takikawa, Hirofumi

    2016-03-01

    Plasma medicine is an emerging research field in which various applications of electrical discharge, especially in the form of nonequilibrium plasma at atmospheric pressure, are examined, for example, the application of plasma to biological targets for various purposes such as selective killing of tumor cells and blood stanching. We have focused on the behavior of an artificial cell membrane system at the solid-liquid interface. To evaluate the lateral lipid mobility, we measured the diffusion coefficient of the supported lipid bilayer (SLB) composed of dioleoylphosphatidylcholine with fluorescence recovery after photobleaching by confocal laser scanning microscopy. It was found that the diffusion coefficient was decreased by plasma irradiation and that the diffusion coefficient decreasing rate proceeded with increasing plasma power. We investigated the effects of stimulation with an equilibrium chemical, H2O2, on the SLB and confirmed that the diffusion coefficient did not change at least up to a H2O2 concentration of 5 mM. These results indicate that transient active species generated by plasma play critical roles in the reduction in SLB fluidity. The effects of the two generated major oxidized lipid species, hydroxyl- or hydroperoxy-phosphatidylcholine (PC) and acyl-chain-truncated PCs terminated with aldehyde or carboxyl group, on lateral lipid mobility are discussed.

  4. Optimizing the electrical excitation of an atmospheric pressure plasma advanced oxidation process.

    Science.gov (United States)

    Olszewski, P; Li, J F; Liu, D X; Walsh, J L

    2014-08-30

    The impact of pulse-modulated generation of atmospheric pressure plasma on the efficiency of organic dye degradation has been investigated. Aqueous samples of methyl orange were exposed to low temperature air plasma and the degradation efficiency was determined by absorbance spectroscopy. The plasma was driven at a constant frequency of 35kHz with a duty cycle of 25%, 50%, 75% and 100%. Relative concentrations of dissolved nitrogen oxides, pH, conductivity and the time evolution of gas phase ozone were measured to identify key parameters responsible for the changes observed in degradation efficiency. The results indicate that pulse modulation significantly improved dye degradation efficiency, with a plasma pulsed at 25% duty showing a two-fold enhancement. Additionally, pulse modulation led to a reduction in the amount of nitrate contamination added to the solution by the plasma. The results clearly demonstrate that optimization of the electrical excitation of the plasma can enhance both degradation efficiency and the final water quality.

  5. 100% N2 atmospheric-pressure microwave-line-plasma production with a modified waveguide structure

    Science.gov (United States)

    Suzuki, Haruka; Tamura, Yuto; Itoh, Hitoshi; Sekine, Makoto; Hori, Masaru; Toyoda, Hirotaka

    2016-09-01

    Large-scale atmospheric pressure (AP) plasmas have been given much attention because of its high cost benefit and a variety of possibilities for industrial applications. Microwave discharge plasma using slot antenna is attractive due to its ability of high-density and stable plasma production, and we have developed a long-scale AP microwave plasma (AP microwave line plasma: AP-MLP) source using loop-structured waveguide and travelling wave and have reported spatially-uniform AP-MLP of 40 cm in length using Ar or He gas discharge. However, rare gas discharge is not always suitable for industrial applications because usage of large volume rare gas degrades the AP cost benefit. Furthermore, many industrial applications require chemically-reactive species and the AP-MLP using molecular gas will drastically increase the applications of the AP-MLP. In this study, we demonstrate 100% N2 discharge of the AP-MLP with a modified waveguide structure. Cross-sectional structure of the waveguide is improved to enhance the microwave electric field in the slot. 100% N2 plasma of 15 cm-long is successfully produced using CW microwave power of 2 kW. Low gas temperature of 1000 K is confirmed by optical emission spectroscopy, suggesting applications of the AP-MLP to low temperature processes. Part of this work is supported by JSPS KAKENHI Grant Number 25286079.

  6. A donut-shape distribution of OH radicals in atmospheric pressure plasma jets

    Science.gov (United States)

    Yue, Yuanfu; Wu, Fan; Cheng, He; Xian, Yubin; Liu, Dawei; Lu, Xinpei; Pei, Xuekai

    2017-01-01

    In this work, OH radicals that have a donut-shape distribution in the room-temperature atmospheric-pressure plasma jet are investigated using the laser-induced fluorescence method. The plasma jet driven by a pulse power supply is operated under two conditions: without the ground electrode and with the ground electrode. It is found that the OH radicals distribute as a donut-shape for the first several pulses under both two conditions. With more pulses applied, the donut-shape disappears and OH radicals distribute as a solid disk. Detailed investigations show that the total OH radicals in the plasma plume are formed from two parts. One part is generated by the plasma plume outside the tube with a structure of a donut-shape. The other part is generated by the plasma inside the tube with a structure of a solid disk, which can be transported to the downstream with gas stream and leads to the disappearance of the donut-shape in the plasma plum. Moreover, when the ground electrode is applied, higher intensity of OH is obtained as well as OH donut-shape distribution is observed with dehumidified working gas. It may be due to the higher electron density and its donut-shape distribution in the effluent according to the simulations and experimental results.

  7. Treatment of Candida albicans biofilms with low-temperature plasma induced by dielectric barrier discharge and atmospheric pressure plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Koban, Ina; Welk, Alexander; Meisel, Peter; Holtfreter, Birte; Kocher, Thomas [Unit of Periodontology, Dental School, University of Greifswald, Rotgerberstr. 8, 17475 Greifswald (Germany); Matthes, Rutger; Huebner, Nils-Olaf; Kramer, Axel [Institute for Hygiene and Environmental Medicine, University of Greifswald, Walther-Rathenau-Str. 49 a, 17487 Greifswald (Germany); Sietmann, Rabea [Institute of Microbiology, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 15, 17487 Greifswald (Germany); Kindel, Eckhard; Weltmann, Klaus-Dieter, E-mail: ina.koban@uni-greifswald.d [Leibniz Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)

    2010-07-15

    Because of some disadvantages of chemical disinfection in dental practice (especially denture cleaning), we investigated the effects of physical methods on Candida albicans biofilms. For this purpose, the antifungal efficacy of three different low-temperature plasma devices (an atmospheric pressure plasma jet and two different dielectric barrier discharges (DBDs)) on Candida albicans biofilms grown on titanium discs in vitro was investigated. As positive treatment controls, we used 0.1% chlorhexidine digluconate (CHX) and 0.6% sodium hypochlorite (NaOCl). The corresponding gas streams without plasma ignition served as negative treatment controls. The efficacy of the plasma treatment was determined evaluating the number of colony-forming units (CFU) recovered from titanium discs. The plasma treatment reduced the CFU significantly compared to chemical disinfectants. While 10 min CHX or NaOCl exposure led to a CFU log{sub 10} reduction factor of 1.5, the log{sub 10} reduction factor of DBD plasma was up to 5. In conclusion, the use of low-temperature plasma is a promising physical alternative to chemical antiseptics for dental practice.

  8. Modelling of plasma generation and thin film deposition by a non-thermal plasma jet at atmospheric pressure

    Science.gov (United States)

    Sigeneger, F.; Becker, M. M.; Foest, R.; Loffhagen, D.

    2016-09-01

    The gas flow and plasma in a miniaturized non-thermal atmospheric pressure plasma jet for plasma enhanced chemical vapour deposition has been investigated by means of hydrodynamic modelling. The investigation focuses on the interplay between the plasma generation in the active zone where the power is supplied by an rf voltage to the filaments, the transport of active plasma particles due to the gas flow into the effluent, their reactions with the thin film precursor molecules and the transport of precursor fragments towards the substrate. The main features of the spatially two-dimensional model used are given. The results of the numerical modelling show that most active particles of the argon plasma are mainly confined within the active volume in the outer capillary of the plasma jet, with the exception of molecular argon ions which are transported remarkably into the effluent together with slow electrons. A simplified model of the precursor kinetics yields radial profiles of precursor fragment fluxes onto the substrate, which agree qualitatively with the measured profiles of thin films obtained by static film deposition experiments.

  9. On the plasma-based growth of ‘flowing’ graphene sheets at atmospheric pressure conditions

    Science.gov (United States)

    Tsyganov, D.; Bundaleska, N.; Tatarova, E.; Dias, A.; Henriques, J.; Rego, A.; Ferraria, A.; Abrashev, M. V.; Dias, F. M.; Luhrs, C. C.; Phillips, J.

    2016-02-01

    A theoretical and experimental study on atmospheric pressure microwave plasma-based assembly of free standing graphene sheets is presented. The synthesis method is based on introducing a carbon-containing precursor (C2H5OH) through a microwave (2.45 GHz) argon plasma environment, where decomposition of ethanol molecules takes place and carbon atoms and molecules are created and then converted into solid carbon nuclei in the ‘colder’ nucleation zones. A theoretical model previously developed has been further updated and refined to map the particle and thermal fluxes in the plasma reactor. Considering the nucleation process as a delicate interplay between thermodynamic and kinetic factors, the model is based on a set of non-linear differential equations describing plasma thermodynamics and chemical kinetics. The model predictions were validated by experimental results. Optical emission spectroscopy was applied to detect the plasma emission related to carbon species from the ‘hot’ plasma zone. Raman spectroscopy, scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy (XPS) techniques have been applied to analyze the synthesized nanostructures. The microstructural features of the solid carbon nuclei collected from the colder zones of plasma reactor vary according to their location. A part of the solid carbon was deposited on the discharge tube wall. The solid assembled from the main stream, which was gradually withdrawn from the hot plasma region in the outlet plasma stream directed to a filter, was composed by ‘flowing’ graphene sheets. The influence of additional hydrogen, Ar flow rate and microwave power on the concentration of obtained stable species and carbon-dicarbon was evaluated. The ratio of sp3/sp2 carbons in graphene sheets is presented. A correlation between changes in C2 and C number densities and sp3/sp2 ratio was found.

  10. Enhancement of antioxidant effects of naringin after atmospheric pressure dielectric barrier discharge plasma treatment.

    Science.gov (United States)

    Kim, Tae Hoon; Jang, Soo Jeung; Chung, Hyung-Wook; Kim, Hyun-Joo; Yong, Hae In; Choe, Wonho; Jo, Cheorun

    2015-03-15

    Naringin is the natural chief bitter flavonoid found in Citrus species. Herein, bitter naringin was treated with atmospheric pressure plasma to afford two new converted flavonoids, narinplasmins A (2) and B (3), along with the known compound, 2R-naringin. The structures of the two new naringin derivatives were elucidated on the basis of spectroscopic methods. The antioxidant activity of all isolates was evaluated based on 1,1-diphenyl-2-picrylhydrazyl and peroxynitrite (ONOO(-)) scavenging assays. The new flavanone glycoside 2 containing a methoxyalkyl group exhibited significantly improved antioxidant properties in these assays relative to the parent naringin.

  11. Fabrication of transparent antifouling thin films with fractal structure by atmospheric pressure cold plasma deposition.

    Science.gov (United States)

    Miyagawa, Hayato; Yamauchi, Koji; Kim, Yoon-Kee; Ogawa, Kazufumi; Yamaguchi, Kenzo; Suzaki, Yoshifumi

    2012-12-21

    Antifouling surface with both superhydrophobicity and oil-repellency has been fabricated on glass substrate by forming fractal microstructure(s). The fractal microstructure was constituted by transparent silica particles of 100 nm diameter and transparent zinc-oxide columns grown on silica particles by atmospheric pressure cold plasma deposition. The sample surface was coated with a chemically adsorbed monomolecular layer. We found that one sample has the superhydrophobic ability with a water droplet contact angle of more than 150°, while another sample has a high transmittance of more than 85% in a wavelength range from 400 to 800 nm.

  12. Effect of Atmospheric Pressure Non-equilibrium Plasmas on Neisseria gonorrhoeae

    Institute of Scientific and Technical Information of China (English)

    涂亚庭; 许莉; 俞莺; 谭明; 李娟; 陈宏翔

    2010-01-01

    In this study,the sterilizing effect of atmospheric pressure nonequilibrium plasmas(APNPs) on Neisseria gonorrhoeae(N.gonorrhoeae) was preliminarily examined and the possible mechanisms were explored.N.gonorrhoeae FA1090,FA19 and MS11 were treated by APNPs and their survival rate was analyzed by using CFUs counting and structurally studied by laser scanning confocal microscopy.The morphological changes of bacterial cell membrane and wall were studied under TEM.Our results showed that APNPs had strong steril...

  13. Synthesis of PPy-like Nanocrystallines by Oriented Plasma Polymerization at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    FANG Xin-sheng; GUO Ying; XU Jin-zhou; ZHANG Jing

    2006-01-01

    Polymeric polypyrrole-like (PPy-like) nanocrystallines were fast synthesized through oriented plasma polymerization at atmospheric pressure and room temperature. The effects of discharge power on the nanocrystalline morphology were investigated. Larger power tends to produce longer nanocrystallines. 3 mm long nanowires were produced at the largest power in our experiment. TEM image and the sharp electronic diffraction spots in SAD suggest that the nanoparticles have a single crystal phase. The chemical structure of the nanocrystalline has been studied through FTIR, EDX etc. This novel polymerization method could have great applications in fabricating functional polymeric nanocrystallines.

  14. Rapid inactivation of Penicillium digitatum spores using high-density nonequilibrium atmospheric pressure plasma

    Science.gov (United States)

    Iseki, Sachiko; Ohta, Takayuki; Aomatsu, Akiyoshi; Ito, Masafumi; Kano, Hiroyuki; Higashijima, Yasuhiro; Hori, Masaru

    2010-04-01

    A promising, environmentally safe method for inactivating fungal spores of Penicillium digitatum, a difficult-to-inactivate food spoilage microorganism, was developed using a high-density nonequilibrium atmospheric pressure plasma (NEAPP). The NEAPP employing Ar gas had a high electron density on the order of 1015 cm-3. The spores were successfully and rapidly inactivated using the NEAPP, with a decimal reduction time in spores (D value) of 1.7 min. The contributions of ozone and UV radiation on the inactivation of the spores were evaluated and concluded to be not dominant, which was fundamentally different from the conventional sterilizations.

  15. Rapid Atmospheric-Pressure-Plasma-Jet Processed Porous Materials for Energy Harvesting and Storage Devices

    Directory of Open Access Journals (Sweden)

    Jian-Zhang Chen

    2015-01-01

    Full Text Available Atmospheric pressure plasma jet (APPJ technology is a versatile technology that has been applied in many energy harvesting and storage devices. This feature article provides an overview of the advances in APPJ technology and its application to solar cells and batteries. The ultrafast APPJ sintering of nanoporous oxides and 3D reduced graphene oxide nanosheets with accompanying optical emission spectroscopy analyses are described in detail. The applications of these nanoporous materials to photoanodes and counter electrodes of dye-sensitized solar cells are described. An ultrashort treatment (1 min on graphite felt electrodes of flow batteries also significantly improves the energy efficiency.

  16. Non-thermal atmospheric pressure plasma activates lactate in Ringer’s solution for anti-tumor effects

    Science.gov (United States)

    Tanaka, Hiromasa; Nakamura, Kae; Mizuno, Masaaki; Ishikawa, Kenji; Takeda, Keigo; Kajiyama, Hiroaki; Utsumi, Fumi; Kikkawa, Fumitaka; Hori, Masaru

    2016-11-01

    Non-thermal atmospheric pressure plasma is a novel approach for wound healing, blood coagulation, and cancer therapy. A recent discovery in the field of plasma medicine is that non-thermal atmospheric pressure plasma not only directly but also indirectly affects cells via plasma-treated liquids. This discovery has led to the use of non-thermal atmospheric pressure plasma as a novel chemotherapy. We refer to these plasma-treated liquids as plasma-activated liquids. We chose Ringer’s solutions to produce plasma-activated liquids for clinical applications. In vitro and in vivo experiments demonstrated that plasma-activated Ringer’s lactate solution has anti-tumor effects, but of the four components in Ringer’s lactate solution, only lactate exhibited anti-tumor effects through activation by non-thermal plasma. Nuclear magnetic resonance analyses indicate that plasma irradiation generates acetyl and pyruvic acid-like groups in Ringer’s lactate solution. Overall, these results suggest that plasma-activated Ringer’s lactate solution is promising for chemotherapy.

  17. An Evaluation of Atmospheric-pressure Plasma for the Cost-Effective Deposition of Antireflection Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Rob Sailer; Guruvenket Srinivasan; Kyle W. Johnson; Douglas L. Schulz

    2010-04-01

    Atmospheric-pressure plasma deposition (APPD) has previously been used to deposit various functional materials including polymeric surface modification layers, transparent conducting oxides, and photo catalytic materials. For many plasma polymerized coatings, reaction occurs via free radical mechanism where the high energy electrons from the plasma activate the olefinic carbon-carbon double bonds - a typical functional group in such precursors. The precursors for such systems are typically inexpensive and readily available and have been used in vacuum PECVD previously. The objectives are to investigate: (1) the effect of plasma power, gas composition and substrate temperature on the Si-based film properties using triethylsilane(TES) as the precursor; and (2) the chemical, mechanical, and optical properties of several experimental matrices based on Design of Experiment (DOE) principals. A simple APPD route has been utilized to deposit Si based films from an inexpensive precursor - Triethylsilane (TES). Preliminary results indicates formation of Si-C & Si-O and Si-O, Si-C & Si-N bonds with oxygen and nitrogen plasmas respectively. N{sub 2}-O{sub 2} plasma showed mixed trend; however oxygen remains a significant portion of all films, despite attempts to minimize exposure to atmosphere. SiN, SiC, and SiO ratios can be modified by the reaction conditions resulting in differing film properties. SE studies revealed that films with SiN bond possess refractive index higher than coatings with Si-O/Si-C bonds. Variable angle reflectance studies showed that SiOCN coatings offer AR properties; however thickness and refractive index optimization of these coatings remains necessary for application as potential AR coatings.

  18. Main species and chemical pathways in cold atmospheric-pressure Ar + H2O plasmas

    Science.gov (United States)

    Liu, Dingxin; Sun, Bowen; Iza, Felipe; Xu, Dehui; Wang, Xiaohua; Rong, Mingzhe; Kong, Michael G.

    2017-04-01

    Cold atmospheric-pressure plasmas in Ar + H2O gas mixtures are a promising alternative to He + H2O plasmas as both can produce reactive oxygen species of relevance for many applications and argon is cheaper than helium. Although He + H2O plasmas have been the subject of multiple experimental and computational studies, Ar + H2O plasmas have received less attention. In this work we investigate the composition and chemical pathways in Ar + H2O plasmas by means of a global model that incorporates 57 species and 1228 chemical reactions. Water vapor concentrations from 1 ppm to saturation (32 000 ppm) are considered in the study and abrupt transitions in power dissipation channels, species densities and chemical pathways are found when the water concentration increases from 100 to 1000 ppm. In this region the plasma transitions from an electropositive discharge in which most power is coupled to electrons into an electronegative one in which most power is coupled to ions. While increasing electronegativity is also observed in He + H2O plasmas, in Ar + H2O plasmas the transition is more abrupt because Penning processes do not contribute to gas ionization and the changes in the electron energy distribution function and mean electron energy caused by the increasing water concentration result in electron-neutral excitation and ionization rates changing by many orders of magnitude in a relatively small range of water concentrations. Insights into the main chemical species and pathways governing the production and loss of electrons, O, OH, OH(A) and H2O2 are provided as part of the study.

  19. Potential cellular targets and antibacterial efficacy of atmospheric pressure non-thermal plasma.

    Science.gov (United States)

    Alkawareek, Mahmoud Y; Gorman, Sean P; Graham, William G; Gilmore, Brendan F

    2014-02-01

    Atmospheric pressure non-thermal plasma (APNTP) has been gaining increasing interest as a new alternative antibacterial approach. Although this approach has demonstrated promising antibacterial activity, its exact mechanism of action remains unclear. Mechanistic elucidation of the antimicrobial activity will facilitate development and rational optimisation of this approach for potential medical applications. In this study, the antibacterial efficacy of an in-house-built APNTP jet was evaluated alongside an investigation of the interactions between APNTP and major cellular components in order to identify the potential cellular targets involved in plasma-mediated bacterial destruction mechanisms. The investigated plasma jet exhibited excellent, rapid antibacterial activity against a selected panel of clinically significant bacterial species including Bacillus cereus, meticillin-resistant Staphylococcus aureus (MRSA), Escherichia coli and Pseudomonas aeruginosa, all of which were completely inactivated within 2 min of plasma exposure. Plasma-mediated damaging effects were observed, to varying degrees, on all of the investigated cellular components including DNA, a model protein enzyme, and lipid membrane integrity and permeability. The antibacterial efficacy of APNTP appears to involve a multiple-target mechanism, which potentially reduces the likelihood of emergence of microbial resistance towards this promising antimicrobial approach. However, cellular membrane damage and resulting permeability perturbation was found to be the most likely rate-determining step in this mechanism.

  20. Cold plasma synthesis of high quality organic nanoparticles at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Radacsi, N., E-mail: kefehu@gmail.com; Heijden, A. E. D. M. van der; Stankiewicz, A. I.; Horst, J. H. ter [Delft University of Technology, Process and Energy Department (Netherlands)

    2013-02-15

    Atmospheric pressure cold surface dielectric barrier discharge (SDBD) plasma was used for the first time to produce nano-sized organic crystals. Nano-sized particles can have beneficial product properties, such as improved internal quality and dissolution rate, compared to conventionally sized crystalline products. In cold plasma crystallization a nebulizer system sprays the solution aerosol into the plasma with the help of a carrier gas. The plasma heats and charges the droplets causing solvent evaporation and coulomb fission to occur, after which nucleation and crystal growth commence within the small, confined volume offered by the small droplets. As a result nano-sized crystals are produced. The operation conditions of SDBD plasma to produce nano-sized crystals of the energetic material RDX were determined by scanning electron microscopy, and the product was investigated with X-ray powder diffraction and sensitivity tests. The sensitivity tests indicated that the nano-sized product had reduced sensitivity for friction, indicating a higher internal quality of the crystalline product.

  1. Transfer of a cold atmospheric pressure plasma jet through a long flexible plastic tube

    Science.gov (United States)

    Kostov, Konstantin G.; Machida, Munemasa; Prysiazhnyi, Vadym; Honda, Roberto Y.

    2015-04-01

    This work proposes an experimental configuration for the generation of a cold atmospheric pressure plasma jet at the downstream end of a long flexible plastic tube. The device consists of a cylindrical dielectric chamber where an insulated metal rod that serves as high-voltage electrode is inserted. The chamber is connected to a long (up to 4 m) commercial flexible plastic tube, equipped with a thin floating Cu wire. The wire penetrates a few mm inside the discharge chamber, passes freely (with no special support) along the plastic tube and terminates a few millimeters before the tube end. The system is flushed with Ar and the dielectric barrier discharge (DBD) is ignited inside the dielectric chamber by a low frequency ac power supply. The gas flow is guided by the plastic tube while the metal wire, when in contact with the plasma inside the DBD reactor, acquires plasma potential. There is no discharge inside the plastic tube, however an Ar plasma jet can be extracted from the downstream tube end. The jet obtained by this method is cold enough to be put in direct contact with human skin without an electric shock. Therefore, by using this approach an Ar plasma jet can be generated at the tip of a long plastic tube far from the high-voltage discharge region, which provides the safe operation conditions and device flexibility required for medical treatment.

  2. Treatment of oral cancer cells with nonthermal atmospheric pressure plasma jet

    Science.gov (United States)

    Yurkovich, James; Han, Xu; Coffey, Benjamin; Klas, Matej; Ptasinska, Sylwia

    2012-10-01

    Non-thermal atmospheric pressure plasmas are specialized types of plasma that are proposed as a new agent to induce death in cancer cells. The experimental phase of this study will test the application of such plasma to SCC-25 oral cancer cells to determine if it is possible to induce apoptosis or necrosis. Different sources are used on the cells to find a configuration which kills cancer cells but has no effect on normal cells. The sources have been developed based on the dielectric barrier discharge between two external electrodes surrounding a dielectric tube; such a configuration has been shown to induce breaks in DNA strands. Each configuration is characterized using an optical emission spectrophotometer and iCCD camera to determine the optimal conditions for inducing cell death. The cells are incubated after irradiation with plasma, and cell death is determined using microscopy imaging to identify antibody interaction within the cells. These studies are important for better understanding of plasma species interactions with cancer cells and mechanisms of DNA damage and at latter stage they will be useful for the development of advanced cancer therapy.

  3. Inactivation Process of Penicillium digitatum Spores Treated with Non-equilibrium Atmospheric Pressure Plasma

    Science.gov (United States)

    Hashizume, Hiroshi; Ohta, Takayuki; Mori, Takumi; Iseki, Sachiko; Hori, Masaru; Ito, Masafumi

    2013-05-01

    To investigate the inactivation process of Penicillium digitatum spores treated with a non-equilibrium atmospheric pressure plasma, the spores were observed using a fluorescent microscope and compared with those treated with ultraviolet (UV) light or moist heat. The treated spores were stained with two fluorescent dyes, 1,1'-dioctadecyl-3,3,Y,3'-tetramethylindocarbocyanine perchlorate (DiI) and diphenyl-1-pyrenylphosphine (DPPP). The intracellular organelles as well as cell membranes in the spores treated with the plasma were stained with DiI without a major morphological change of the membranes, while the organelles were never stained in the spores treated with UV light or moist heat. Moreover, DPPP staining revealed that organelles were oxidized by plasma treatment unlike UV light or moist heat treatments. These results suggest that only plasma treatment induces a minor structural change or functional inhibition of cell membranes, which leads to the oxidation of the intracellular organelles without a major deformation of the membranes through the penetration of reactive oxygen species generated by the plasma into the cell.

  4. Inactivation of virus in solution by cold atmospheric pressure plasma: identification of chemical inactivation pathways

    Science.gov (United States)

    Aboubakr, Hamada A.; Gangal, Urvashi; Youssef, Mohammed M.; Goyal, Sagar M.; Bruggeman, Peter J.

    2016-05-01

    Cold atmospheric pressure plasma (CAP) inactivates bacteria and virus through in situ production of reactive oxygen and nitrogen species (RONS). While the bactericidal and virucidal efficiency of plasmas is well established, there is limited knowledge about the chemistry leading to the pathogen inactivation. This article describes a chemical analysis of the CAP reactive chemistry involved in the inactivation of feline calicivirus. We used a remote radio frequency CAP produced in varying gas mixtures leading to different plasma-induced chemistries. A study of the effects of selected scavengers complemented with positive control measurements of relevant RONS reveal two distinctive pathways based on singlet oxygen and peroxynitrous acid. The first mechanism is favored in the presence of oxygen and the second in the presence of air when a significant pH reduction is induced in the solution by the plasma. Additionally, smaller effects of the H2O2, O3 and \\text{NO}2- produced were also found. Identification of singlet oxygen-mediated 2-imidazolone/2-oxo-His (His  +14 Da)—an oxidative modification of His 262 comprising the capsid protein of feline calicivirus links the plasma induced singlet oxygen chemistry to viral inactivation.

  5. Melting and spheroidization of hexagonal boron nitride in a microwave-powered, atmospheric pressure nitrogen plasma `

    Energy Technology Data Exchange (ETDEWEB)

    Gleiman, S. S. (Seth S.); Phillips, J. (Jonathan)

    2001-01-01

    We have developed a method for producing spherically-shaped, hexagonal phase boron nitride (hBN) particles of controlled diameter in the 10-100 micron size range. Specifically, platelet-shaped hBN particles are passed as an aerosol through a microwave-generated, atmospheric pressure, nitrogen plasma. In the plasma, agglomerates formed by collisions between input hBN particles, melt and forms spheres. We postulate that this unprecedented process takes place in the unique environment of a plasma containing a high N-atom concentration, because in such an environment the decomposition temperature can be raised above the melting temperature. Indeed, given the following relationship [1]: BN{sub (condensed)} {leftrightarrow} B{sub (gas)} + N{sub (gas)}. Standard equilibrium thermodynamics indicate that the decomposition temperature of hBN is increased in the presence of high concentrations of N atoms. We postulate that in our plasma system the N atom concentration is high enough to raise the decomposition temperature above the (undetermined) melting temperature. Keywords Microwave plasma, boron nitride, melting, spherical, thermodynamics, integrated circuit package.

  6. [Comparative study on the gas temperature of a plasma jet at atmospheric pressure].

    Science.gov (United States)

    Jia, Peng-Ying; Li, Xue-Chen; Yuan, Ning

    2011-08-01

    A plasma jet of a dielectric barrier discharge in coaxial electrode was used to produce jet plasma in flowing work gas (argon mixed with trace nitrogen) at atmospheric pressure. The relation between the plasma length and the gas flow rate was obtained by taking the images of the jet plasma. A high-resolution optical spectrometer was used to collect the optical emission spectrum. The emission spectra of the first negative band of N(2+) (B2 Sigma(u+)-->Chi2 Sigma(g+), 390-391.6 nm) were used to estimate the rotational temperature of the plasma plume by fitting the experimental spectra to the simulated spectra. The gas temperature was investigated by this optical method and results show that the gas temperature increases with increasing the applied voltage. For comparison, a thermometer was used to measure the temperature of the gas emitted from the jet. The results also show that the gas temperature increases with increasing the applied voltage. The gas temperatures obtained by the two methods are consistent. The difference was analyzed.

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

    Directory of Open Access Journals (Sweden)

    Asma Begum

    2013-06-01

    Full Text Available 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 1011 cm-3 and it reaches to the maximum of 1012 cm-3.

  8. The Oblique Incident Effects of Electromagnetic Wave in Atmospheric Pressure Plasma Layers

    Institute of Scientific and Technical Information of China (English)

    HE Yong; JIANG Zhonghe; HU Xiwei; LIU Minghai

    2008-01-01

    The propagating behaviours, i.e. phase shift, transmissivity, reflectivity and absorptivity, of an electromagnetic (EM) wave in a two-dimensional atmospheric pressure plasma layer are described by the numerical solutions of integral-differential Maxwell's equations through a generalized finite-difference-time-domain (FDTD) algorithm. These propagating behaviours are found to be strongly affected by five factors: two EM wave characteristics relevan.t to the oblique incident and three dimensionless factors. The two EM wave factors are the polarization mode (TM mode or TE mode) and its incident angle. The three dimensionless factors are: the ratio of the maximum electron density to the critical density n0/ncr, the ratio of the plasma layer width to the wave length d/λ, and the ratio of the collision frequency between electrons and neutrals to the incident wave frequency ve0/f.

  9. Gas mixing enhanced by power modulations in atmospheric pressure microwave plasma jet

    Science.gov (United States)

    Voráč, J.; Potočňáková, L.; Synek, P.; Hnilica, J.; Kudrle, V.

    2016-04-01

    Microwave plasma jet operating in atmospheric pressure argon was power modulated by audio frequency sine envelope in the 102 W power range. Its effluent was imaged using interference filters and ICCD camera for several different phases of the modulating signal. The combination of this fast imaging with spatially resolved optical emission spectroscopy provides useful insights into the plasmachemical processes involved. Phase-resolved schlieren photography was performed to visualize the gas dynamics. The results show that for higher modulation frequencies the plasma chemistry is strongly influenced by formation of transient flow perturbation resembling a vortex during each period. The perturbation formation and speed are strongly influenced by the frequency and power variations while they depend only weakly on the working gas flow rate. From application point of view, the perturbation presence significantly broadened lateral distribution of active species, effectively increasing cross-sectional area suitable for applications.

  10. A model for plasma modification of polypropylene using atmospheric pressure discharges

    CERN Document Server

    Dorai, R

    2003-01-01

    Atmospheric pressure plasmas are commonly used to improve the wetting and adhesion properties of polymers. In spite of their use, the mechanisms for achieving these properties are unclear. In this regard, we report on a computational investigation of the gas phase and surface kinetics during humid-air corona treatment of polypropylene (PP) and the resulting modification of its surface properties while varying energy deposition, relative humidity (RH), web speed, and gas temperature. Using results from a global plasma chemistry model validated against experiments, we found that increasing energy deposition increased the densities of alcohol, carbonyl, acid, and peroxy radicals on the PP surface. In doing so, significant amounts of gas phase O sub 3 and N sub x O sub y are produced. Increasing the RH increased the production of peroxy and acid groups, while decreasing those of alcohol and carbonyl groups. Production of O sub 3 decreased while that of HNO sub 3 increased. Increasing the temperature decreased the...

  11. Pro-apoptotic NOXA is implicated in atmospheric-pressure plasma-induced melanoma cell death

    Science.gov (United States)

    Ishaq, M.; Bazaka, K.; Ostrikov, K.

    2015-11-01

    Atmospheric-pressure plasma (APP) has been successfully used to treat several types of cancers in vivo and in vitro, with the effect being primarily attributed to the generation of reactive oxygen species (ROS). However, the mechanisms by which APP induces apoptosis in cancer cells require further elucidation. In this study, the effects of APP on the expression of 500 genes in melanoma Mel007 cancer cells were examined. Pro-apoptotic phorbol-12-myristate-13-acetate-induced protein (PMAIP1), also known as NOXA, was highly expressed as a result of APP treatment in a dose-dependent manner. Blocking of ROS using scavenger NAC or silencing of NOXA gene by RNA interference inhibited the APP-induced NOXA genes upregulation and impaired caspases 3/7 mediated apoptosis, confirming the important role plasma-generated ROS species and pro-apoptotic NOXA play in APP-induced cancer cell death.

  12. Generation and characterization of OH and O radicals by atmospheric pressure steam/oxygen plasma

    CERN Document Server

    Roy, N C; Alam, M K; Talukder, M R

    2016-01-01

    Atmospheric pressure steam/oxygen plasma is generated by a 88 Hz, 6kV AC power supply. The properties of the produced plasma are investigated by optical emission spectroscopy (OES). The relative intensity, rotational, vibrational, excitation temperatures and electron density are studied as function of applied voltage, electrode spacing and oxygen flow rate. The rotational and vibrational temperatures are determined simulating the bands with the aid of LIFBASE simulation software. The excitation temperature is obtained from the CuI transition taking non-thermal equilibrium condition into account employing intensity ratio method. The electron density is approximated from the H_{\\alpha} Stark broadening using the Voigt profile fitting method. It is observed that the rotational and vibrational temperatures are decreased with increasing electrode spacing and O2 flow rate, but increased with the applied voltage. The excitation temperature is found to increase with increasing applied voltage and O2 flow rate, but de...

  13. Application of atmospheric pressure plasma polishing method in machining of silicon ultra-smooth surfaces

    Institute of Scientific and Technical Information of China (English)

    Jufan ZHANG; Bo WANG; Shen DONG

    2008-01-01

    The modern optics industry demands rigorous surface quality with minimum defects, which presents challenges to optics machining technologies. There are always certain defects on the final surfaces of the compo-nents formed in conventional contacting machining proc-esses, such as micro-cracks, lattice disturbances, etc. It is especially serious for hard-brittle functional materials, such as crystals, glass and ceramics because of their special characteristics. To solve these problems, the atmospheric pressure plasma polishing (APPP) method is developed. It utilizes chemical reactions between reactive plasma and surface atoms to perform atom-scale material removal. Since the machining process is chemical in nature, APPP avoids the surface/subsurface defects mentioned above. As the key component, a capacitance coupled radio-fre-quency plasma torch is first introduced. In initial opera-tions, silicon wafers were machined as samples. Before applying operations, both the temperature distribution on the work-piece surface and the spatial gas diffusion in the machining process were studied qualitatively by finite element analysis. Then the following temperature measurement experiments demonstrate the formation of the temperature gradient on the wafer surface predicted by the theoretical analysis and indicated a peak temper-ature about 90℃ in the center. By using commercialized form talysurf, the machined surface was detected and the result shows regular removal profile that corresponds well to the flow field model. Moreover, the removal profile also indicates a 32 mm3/min removal rate. By using atomic force microscopy (AFM), the surface roughness was also measured and the result demonstrates an Ra 0.6 nm surface roughness. Then the element composition of the machined surface was detected and analyzed by X-ray photoelectron spectroscopy (XPS) technology. The results also demonstrate the occurrence of the anticipated main reactions. All the experiments have proved that

  14. Form control in atmospheric pressure plasma processing of ground fused silica

    Science.gov (United States)

    Li, Duo; Wang, Bo; Xin, Qiang; Jin, Huiliang; Wang, Jun; Dong, Wenxia

    2014-08-01

    Atmospheric Pressure Plasma Processing (APPP) using inductively coupled plasma has demonstrated that it can achieve comparable removal rate on the optical surface of fused silica under the atmosphere pressure and has the advantage of inducing no sub-surface damage for its non-contact and chemical etching mechanism. APPP technology is a cost effective way, compared with traditional mechanical polishing, magnetorheological finishing and ion beam figuring. Thus, due to these advantages, this technology is being tested to fabricate large aperture optics of fused silica to help shorten the polishing time in optics fabrication chain. Now our group proposes to use inductively coupled plasma processing technology to fabricate ground surface of fused silica directly after the grinding stage. In this paper, form control method and several processing parameters are investigated to evaluate the removal efficiency and the surface quality, including the robustness of removal function, velocity control mode and tool path strategy. However, because of the high heat flux of inductively coupled plasma, the removal depth with time can be non-linear and the ground surface evolvement will be affected. The heat polishing phenomenon is founded. The value of surface roughness is reduced greatly, which is very helpful to reduce the time of follow-up mechanical polishing. Finally, conformal and deterministic polishing experiments are analyzed and discussed. The form error is less 3%, before and after the APPP, when 10μm depth of uniform removal is achieved on a 60×60mm ground fused silica. Also, a basin feature is fabricated to demonstrate the figuring capability and stability. Thus, APPP is a promising technology in processing the large aperture optics.

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

    Science.gov (United States)

    Chang, Zhengshi; Yao, Congwei; Zhang, Guanjun

    2016-01-01

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

  16. Surface modification of tube inner wall by transferred atmospheric pressure plasma

    Science.gov (United States)

    Chen, Faze; Liu, Shuo; Liu, Jiyu; Huang, Shuai; Xia, Guangqing; Song, Jinlong; Xu, Wenji; Sun, Jing; Liu, Xin

    2016-12-01

    Tubes are indispensable in our daily life, mechanical engineering and biomedical fields. However, the practical applications of tubes are sometimes limited by their poor wettability. Reported herein is hydrophilization of the tube inner wall by transferred atmospheric pressure plasma (TAPP). An Ar atmospheric pressure plasma jet (APPJ) is used to induce He TAPP inside polytetrafluoroethylene (PTFE) tube to perform inner wall surface modification. Optical emission spectrum (OES) is used to investigate the distribution of active species, which are known as enablers for surface modification, along the TAPP. Tubes' surface properties demonstrate that after TAPP treatment, the wettability of the tube inner wall is well improved due to the decrease of surface roughness, the removal of surface fluorine and introduction of oxygen. Notably, a deep surface modification can significantly retard the aging of the obtained hydrophilicity. The results presented here clearly demonstrate the great potential of TAPP for surface modification of the inner wall of tube or other hollow bodies, and thus a uniform, effective and long-lasting surface modification of tube with any length can be easily realized by moving the tube along its axis.

  17. Cold atmospheric pressure plasma treatment of ready-to-eat meat: Inactivation of Listeria innocua and changes in product quality

    DEFF Research Database (Denmark)

    Röd, Sara Katrine; Hansen, Flemming; Leipold, Frank;

    Sliced ready-to-eat (RTE) meat products are susceptible to growth of the foodborne pathogenic bacterium, Listeria monocytogenes. Cold atmospheric pressure plasma (CAPP) may be applicable for surface decontamination in sealed bags thus avoiding recontamination. Plasmas (Fig. 1), created in neutral...

  18. Crednerite-CuMnO{sub 2} thin films prepared using atmospheric pressure plasma annealing

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hong-Ying, E-mail: hychen@cc.kuas.edu.tw [Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, 415 Chiken Kuang Road, Kaohsiung 807, Taiwan, ROC (China); Lin, Yu-Chang [Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, 415 Chiken Kuang Road, Kaohsiung 807, Taiwan, ROC (China); Lee, Jiann-Shing [Department of Applied Physics, National Pingtung University, 4-18 Minsheng Road, Pingtung City 900, Taiwan, ROC (China)

    2015-05-30

    Highlights: • Crednerite-CuMnO{sub 2} thin films were formed at atmospheric pressure plasma with N{sub 2}–(5–10)%O{sub 2}. • The binding energy of Cu-2p spectrum of the crednerite-CuMnO{sub 2} thin films was 932.3 eV (Cu{sup +}). • The binding energies of Mn-3p spectrum were 48.1 ± 0.2 eV (Mn{sup 3+}) and 50.0 ± 0.2 eV (Mn{sup 4+}). • The cation distribution in the crednerite-CuMnO{sub 2} thin films was Cu{sub 1.0}{sup +}(Mn{sub 0.6}{sup 3+}Mn{sub 0.4}{sup 4+})O{sub 2}. • The electrical conductivity of CuMnO{sub 2} thin films was (2.61–2.65) × 10{sup 4} Ω cm. - Abstract: This study reports the preparation of crednerite-CuMnO{sub 2} thin films using atmospheric pressure plasma annealing. The pristine thin films were deposited onto a quartz substrate using the sol–gel process. The specimens were then annealed using atmospheric pressure plasma at N{sub 2}–(0–20%)O{sub 2} for 20 min. Crednerite-CuMnO{sub 2} thin films were obtained using atmospheric pressure plasma annealing at N{sub 2}–5%O{sub 2} and N{sub 2}–10%O{sub 2}. The lattice parameters of the thin films were a = 0.5574–0.5580 nm, b = 0.2874–0.2879 nm, c = 0.5878–0.5881 nm, and β = 104.15–104.25°, which agree well with previous reports. The Raman shifts of the crednerite-CuMnO{sub 2} thin films were 688 ± 2 cm{sup −1}, 381 ± 2 cm{sup −1}, and 314 ± 2 cm{sup −1}. The binding energy of Cu-2p spectrum of the crednerite-CuMnO{sub 2} thin films was 932.3 ± 0.2 eV representing the Cu{sup +} in the thin films. The binding energies of Mn-3p spectrum were 48.1 ± 0.2 eV (Mn{sup 3+}) and 50.0 ± 0.2 eV (Mn{sup 4+}). Furthermore, the cation distribution in the thin films was Cu{sup +}{sub 1.0}(Mn{sup 3+}{sub 0.6}Mn{sup 4+}{sub 0.4})O{sub 2} from the X-ray photoelectron spectroscopy measurement. When the crednerite-CuMnO{sub 2} phase was formed, the surface morphology exhibited a compact/dense granular morphology. The optical bandgap of the crednerite-CuMnO{sub 2} thin

  19. Plasma treatment of carbon fibres and glass-fibre-reinforced polyesters at atmospheric pressure for adhesion improvement

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Løgstrup Andersen, Tom; Toftegaard, Helmuth Langmaack

    2014-01-01

    Atmospheric pressure plasma treatment is useful for adhesion improvement, because cleaning, roughening and addition of polar functional groups can be expected at the surfaces. Its possible applications in the wind energy industry include plasma treatment of fibres and fibre-reinforced polymer...... composites before assembling them to build wind turbine blades. In the present work, unsized carbon fibres are continuously treated using a dielectric barrier discharge plasma in helium at atmospheric pressure, and carbon fibre reinforced epoxy composite plates are manufactured for the mechanical test...

  20. Atmospheric pressure plasma jet for bacterial decontamination and property improvement of fruit and vegetable processing wastewater

    Science.gov (United States)

    Mohamed, Abdel-Aleam H.; Shariff, Samir M. Al; Ouf, Salama A.; Benghanem, Mohamed

    2016-05-01

    An atmospheric pressure plasma jet was tested for decontaminating and improving the characteristics of wastewater derived from blackberry, date palm, tomato and beetroot processing industries. The jet was generated by blowing argon gas through a cylindrical alumina tube while a high voltage was applied between two electrodes surrounding the tube. Oxygen gas was mixed with argon at the rate of 0.2% and the argon mass flow was fixed at 4.5 slm. Images show that the generated plasma jet penetrated the treated wastewater samples. Plasma emission spectra show the presence of O and OH radicals as well as excited molecular nitrogen and argon. Complete decontamination of wastewater derived from date palm and tomato processing was achieved after 120 and 150 s exposure to the plasma jet, respectively. The bacterial count of wastewater from blackberry and beetroot was reduced by 0.41 and 2.24 log10 colony-forming units (CFU) per ml, respectively, after 180 s. Escherichia coli was the most susceptible bacterial species to the cold plasma while Shigella boydii had the minimum susceptibility, recording 1.30 and 3.34 log10 CFU ml-1, respectively, as compared to the 7.00 log10 initial count. The chemical oxygen demands of wastewater were improved by 57.5-93.3% after 180 s exposure to the plasma jet being tested. The endotoxins in the wastewater were reduced by up to 90.22%. The variation in plasma effectiveness is probably related to the antioxidant concentration of the different investigated wastewaters.

  1. Decontamination of Chemical/Biological Warfare (CBW) Agents Using an Atmospheric Pressure Plasma Jet (APPJ)

    Science.gov (United States)

    Herrmann, Hans W.

    1998-11-01

    The atmospheric pressure plasma jet (APPJ) is a non-thermal, high pressure, uniform glow discharge that produces a high velocity effluent stream of highly reactive chemical species. The discharge operates on a feedstock gas (e.g. He/O_2/H_2O) which flows between an outer, grounded, cylindrical electrode and an inner, coaxial electrode powered at 13.56 MHz RF. While passing through the plasma, the feedgas becomes excited, dissociated or ionized by electron impact. Once the gas exits the discharge volume, ions and electrons are rapidly lost by recombination, but the fast-flowing effluent still contains metastables (e.g. O2*, He*) and radicals (e.g. O, OH). These reactive species have been shown to be effective neutralizers of surrogates for anthrax spores, mustard blister agent and VX nerve gas. Unlike conventional, wet decontamination methods, the plasma effluent does not cause corrosion of most surfaces and does not damage wiring, electronics, nor most plastics. This makes it highly suitable for decontamination of high value sensitive equipment such as is found in vehicle interiors (i.e. tanks, planes...) for which there is currently no good decontamination technique. Furthermore, the reactive species rapidly degrade into harmless products leaving no lingering residue or harmful byproducts. Physics of the APPJ will be discussed and results of surface decontamination experiments using simulant and actual CBW agents will be presented.

  2. Simulation Tool for Dielectric Barrier Discharge Plasma Actuators at Atmospheric and Sub-Atmospheric Pressures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Traditional approaches for active flow separation control using dielectric barrier discharge (DBD) plasma actuators are limited to relatively low-speed flows and...

  3. Cold atmospheric pressure plasma and decontamination. Can it contribute to preventing hospital-acquired infections?

    Science.gov (United States)

    O'Connor, N; Cahill, O; Daniels, S; Galvin, S; Humphreys, H

    2014-10-01

    Healthcare-associated infections (HCAIs) affect ∼4.5 million patients in Europe alone annually. With the ever-increasing number of 'multi-resistant' micro-organisms, alternative and more effective methods of environmental decontamination are being sought as an important component of infection prevention and control. One of these is the use of cold atmospheric pressure plasma (CAPP) systems with clinical applications in healthcare facilities. CAPPs have been shown to demonstrate antimicrobial, antifungal and antiviral properties and have been adopted for other uses in clinical medicine over the past decade. CAPPs vary in their physical and chemical nature depending on the plasma-generating mechanism (e.g. plasma jet, dielectric barrier discharge, etc.). CAPP systems produce a 'cocktail' of species including positive and negative ions, reactive atoms and molecules (e.g. atomic oxygen, ozone, superoxide and oxides of nitrogen), intense electric fields, and ultraviolet radiation (UV). The effects of these ions have been studied on micro-organisms, skin, blood, and DNA; thus, a range of possible applications of CAPPs has been identified, including surface decontamination, wound healing, biofilm removal, and even cancer therapy. Here we evaluate plasma devices, their applications, mode of action and their potential role specifically in combating HCAIs on clinical surfaces.

  4. The role of VUV radiation in the inactivation of bacteria with an atmospheric pressure plasma jet

    CERN Document Server

    Schneider, Simon; Ellerweg, Dirk; Denis, Benjamin; Narberhaus, Franz; Bandow, Julia E; Benedikt, Jan

    2011-01-01

    A modified version of a micro scale atmospheric pressure plasma jet (\\mu-APPJ) source, so-called X-Jet, is used to study the role of plasma generated VUV photons in the inactivation of E. coli bacteria. The plasma is operated in He gas or a He/O2 mixture and the X-Jet modification of the jet geometry allows effective separation of heavy reactive particles (such as O atoms or ozone molecules) from the plasma-generated photons. The measurements of the evolution of zone of inhibitions formed in monolayers of vegetative E. coli bacteria, of VUV emission intensity and of positive ion spectra show that photochemistry in the gas phase followed by photochemistry products impacting on bacteria can result in bacterial inactivation. Interestingly, this process is more effective than direct inactivation by VUV radiation damage. Mainly protonated water cluster ions are detected by mass spectrometry indicating that water impurity has to be carefully considered. The measurements indicate that the combination of the presence...

  5. Atmospheric pressure plasma deposition of antimicrobial coatings on non-woven textiles

    Science.gov (United States)

    Nikiforov, Anton Yu.; Deng, Xiaolong; Onyshchenko, Iuliia; Vujosevic, Danijela; Vuksanovic, Vineta; Cvelbar, Uros; De Geyter, Nathalie; Morent, Rino; Leys, Christophe

    2016-08-01

    A simple method for preparation of nanoparticle incorporated non-woven fabric with high antibacterial efficiency has been proposed based on atmospheric pressure plasma process. In this work direct current plasma jet stabilized by fast nitrogen flow was used as a plasma deposition source. Three different types of the nanoparticles (silver, copper and zinc oxide nanoparticles) were employed as antimicrobial agents. X-ray photoelectron spectroscopy (XPS) measurements have shown a positive chemical shift observed for Ag 3d 5/2 (at 368.1 eV) suggests that silver nanoparticles (AgNPs) are partly oxidized during the deposition. The surface chemistry and the antibacterial activity of the samples against Staphylococcus aureus and Escherichia coli were investigated and analyzed. It is shown that the samples loaded with nanoparticles of Ag and Cu and having the barrier layer of 10 nm characterized by almost 97% of bacterial reduction whereas the samples with ZnO nanoparticles provide 86% reduction of Staphylococcus aureus. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  6. Inactivation of Gram-positive biofilms by low-temperature plasma jet at atmospheric pressure

    Science.gov (United States)

    Marchal, F.; Robert, H.; Merbahi, N.; Fontagné-Faucher, C.; Yousfi, M.; Romain, C. E.; Eichwald, O.; Rondel, C.; Gabriel, B.

    2012-08-01

    This work is devoted to the evaluation of the efficiency of a new low-temperature plasma jet driven in ambient air by a dc-corona discharge to inactivate adherent cells and biofilms of Gram-positive bacteria. The selected microorganisms were lactic acid bacteria, a Weissella confusa strain which has the particularity to excrete a polysaccharide polymer (dextran) when sucrose is present. Both adherent cells and biofilms were treated with the low-temperature plasma jet for different exposure times. The antimicrobial efficiency of the plasma was tested against adherent cells and 48 h-old biofilms grown with or without sucrose. Bacterial survival was estimated using both colony-forming unit counts and fluorescence-based assays for bacterial cell viability. The experiments show the ability of the low-temperature plasma jet at atmospheric pressure to inactivate the bacteria. An increased resistance of bacteria embedded within biofilms is clearly observed. The resistance is also significantly higher with biofilm in the presence of sucrose, which indicates that dextran could play a protective role.

  7. Mechanistic insights into the impact of Cold Atmospheric Pressure Plasma on human epithelial cell lines

    Science.gov (United States)

    Dezest, Marlène; Chavatte, Laurent; Bourdens, Marion; Quinton, Damien; Camus, Mylène; Garrigues, Luc; Descargues, Pascal; Arbault, Stéphane; Burlet-Schiltz, Odile; Casteilla, Louis; Clément, Franck; Planat, Valérie; Bulteau, Anne-Laure

    2017-01-01

    Compelling evidence suggests that Cold Atmospheric Pressure Plasma (CAPP) has potential as a new cancer therapy. However, knowledge about cellular signaling events and toxicity subsequent to plasma treatment is still poorly documented. The aim of this study was to focus on the interaction between 3 different types of plasma (He, He-O2, He-N2) and human epithelial cell lines to gain better insight into plasma-cell interaction. We provide evidence that reactive oxygen and nitrogen species (RONS) are inducing cell death by apoptosis and that the proteasome, a major intracellular proteolytic system which is important for tumor cell growth and survival, is a target of (He or He-N2) CAPP. However, RONS are not the only actors involved in cell death; electric field and charged particles could play a significant role especially for He-O2 CAPP. By differential label-free quantitative proteomic analysis we found that CAPP triggers antioxidant and cellular defense but is also affecting extracellular matrix in keratinocytes. Moreover, we found that malignant cells are more resistant to CAPP treatment than normal cells. Taken together, our findings provide insight into potential mechanisms of CAPP-induced proteasome inactivation and the cellular consequences of these events. PMID:28120925

  8. Mechanistic insights into the impact of Cold Atmospheric Pressure Plasma on human epithelial cell lines

    Science.gov (United States)

    Dezest, Marlène; Chavatte, Laurent; Bourdens, Marion; Quinton, Damien; Camus, Mylène; Garrigues, Luc; Descargues, Pascal; Arbault, Stéphane; Burlet-Schiltz, Odile; Casteilla, Louis; Clément, Franck; Planat, Valérie; Bulteau, Anne-Laure

    2017-01-01

    Compelling evidence suggests that Cold Atmospheric Pressure Plasma (CAPP) has potential as a new cancer therapy. However, knowledge about cellular signaling events and toxicity subsequent to plasma treatment is still poorly documented. The aim of this study was to focus on the interaction between 3 different types of plasma (He, He-O2, He-N2) and human epithelial cell lines to gain better insight into plasma-cell interaction. We provide evidence that reactive oxygen and nitrogen species (RONS) are inducing cell death by apoptosis and that the proteasome, a major intracellular proteolytic system which is important for tumor cell growth and survival, is a target of (He or He-N2) CAPP. However, RONS are not the only actors involved in cell death; electric field and charged particles could play a significant role especially for He-O2 CAPP. By differential label-free quantitative proteomic analysis we found that CAPP triggers antioxidant and cellular defense but is also affecting extracellular matrix in keratinocytes. Moreover, we found that malignant cells are more resistant to CAPP treatment than normal cells. Taken together, our findings provide insight into potential mechanisms of CAPP-induced proteasome inactivation and the cellular consequences of these events.

  9. Dual effects of atmospheric pressure plasma jet on skin wound healing of mice.

    Science.gov (United States)

    Xu, Gui-Min; Shi, Xing-Min; Cai, Jing-Fen; Chen, Si-Le; Li, Ping; Yao, Cong-Wei; Chang, Zheng-Shi; Zhang, Guan-Jun

    2015-01-01

    Cold plasma has become an attractive tool for promoting wound healing and treating skin diseases. This article presents an atmospheric pressure plasma jet (APPJ) generated in argon gas through dielectric barrier discharge, which was applied to superficial skin wounds in BALB/c mice. The mice (n = 50) were assigned randomly into five groups (named A, B, C, D, E) with 10 animals in each group. Natural wound healing was compared with stimulated wound healing treated daily with APPJ for different time spans (10, 20, 30, 40, and 50 seconds) on 14 consecutive days. APPJ emission spectra, morphological changes in animal wounds, and tissue histological parameters were analyzed. Statistical results revealed that wound size changed over the duration of the experimental period and there was a significant interaction between experimental day and group. Differences between group C and other groups at day 7 were statistically significant (p plasma could inactivate bacteria around the wound, activate fibroblast proliferation in wound tissue, and eventually promote wound healing. Whereas, over doses of plasma suppressed wound healing due to causing cell death by apoptosis or necrosis. Both positive and negative effects may be related to the existence of reactive oxygen and nitrogen species (ROS and RNS) in APPJ.

  10. [Investigation on the electron density of a micro-plasma jet operated at atmospheric pressure].

    Science.gov (United States)

    Li, Xue-chen; Zhao, Na; Liu, Wei-yuan; Liu, Zhi-qiang

    2010-07-01

    In the present paper, a micro-hollow cathode discharge setup was used to generate micro-plasma jet in flowing mixture of Ar and N2 at atmospheric pressure. The characteristics of the micro-plasma jet were investigated by means of optical method and electrical one. It has been found that breakdown occurs in the gas between the two electrodes when the input power of electric source is increased to a certain value. Plasma appears along the gas flow direction when the mixed gas flows from the aperture of the micro-hollow cathode, and the length of plasma reaches 4 mm. The discharge current is quasi-continuous, and the duration of discharge pulse is about 0.1 micros. Electron density was studied by using Einstein equation and Stark broadening of spectral lines from the emission spectrum respectively. It was found that the results of electron density calculated by the two methods are consistent with the order of 10(15) x cm(-3). It was also found that the electron density is almost independent of power. A qualitative explanation to the phenomenon is given based on the gas discharge theory.

  11. A low power miniaturized dielectric barrier discharge based atmospheric pressure plasma jet

    Science.gov (United States)

    Divya Deepak, G.; Joshi, N. K.; Pal, Dharmendra Kumar; Prakash, Ram

    2017-01-01

    In this paper, a dielectric barrier discharge plasma based atmospheric pressure plasma jet has been generated in a floating helix and floating end ring electrode configuration using argon and helium gases. This configuration is subjected to a range of supply frequencies (10-25 kHz) and supply voltages (2-6 kV) at a fixed rate of gas flow rate (i.e., 1 l/min). The electrical characterization of the plasma jet has been carried out using a high voltage probe and current transformer. The current-voltage characteristics have been analyzed, and the consumed power has been estimated at different applied combinations for optimum power consumption at maximum jet length. The obtained optimum power and jet length for argon and helium gases are 12 mW and 32 mm, and 7.7 mW and 42 mm, respectively. It is inferred that besides the electrode configurations, the discharge gas is also playing a significant role in the low power operation of the cold plasma jet at maximum jet length. The obtained results are interpreted on the basis of penning processes.

  12. Laser diagnostics on atmospheric pressure discharge plasmas, including cryoplasmas, in environments around room and cryogenic temperature

    Science.gov (United States)

    Sakakibara, Noritaka; Muneoka, Hitoshi; Urabe, Keiichiro; Yasui, Ryoma; Sakai, Osamu; Terashima, Kazuo

    2017-04-01

    Cryoplasmas, the plasma gas temperature (T g) of which can be controlled continuously below room temperature, show various unique and advantageous properties depending on T g. Recently, the T g dependence of plasma chemistry related to metastable helium (Hem) has been revealed in helium cryoplasmas. However, T g was only estimated by thermal calculation from the temperature outside the plasmas. In this study, for better evaluation of T g, near-infrared laser heterodyne interferometry (NIR-LHI) measurements were conducted in atmospheric pressure helium pulsed discharge plasmas at around room and cryogenic ambient temperatures (T a). The maximum difference between T g and T a was evaluated as 47 K at T a  =  300 K with 282 mW power consumption. To further investigate the T g dependence of plasma chemical reactions related to Hem, laser absorption spectroscopy (LAS) was performed on the same discharge plasmas to measure the Hem density and lifetime. The Hem lifetime was longer at lower T g, i.e. the lifetime at T g  =  145 K (9.6 µs) was seven times longer than that at T g  =  386 K (1.4 µs). By comparing the results with the numerically simulated rates of Hem quenching reactions taking T g into account, the mechanism of the Hem quenching reaction was revealed to vary with T g even though the main quenching reaction was a three-body collision at all T g. In this manner, the combination of NIR-LHI with LAS led directly to the T g dependence of Hem quenching reactions.

  13. plasmatis Center for Innovation Competence: Controlling reactive component output of atmospheric pressure plasmas in plasma medicine

    Science.gov (United States)

    Reuter, Stephan

    2012-10-01

    The novel approach of using plasmas in order to alter the local chemistry of cells and cell environment presents a significant development in biomedical applications. The plasmatis center for innovation competence at the INP Greifswald e.V. performs fundamental research in plasma medicine in two interdisciplinary research groups. The aim of our plasma physics research group ``Extracellular Effects'' is (a) quantitative space and time resolved diagnostics and modelling of plasmas and liquids to determine distribution and composition of reactive species (b) to control the plasma and apply differing plasma source concepts in order to produce a tailored output of reactive components and design the chemical composition of the liquids/cellular environment and (c) to identify and understand the interaction mechanisms of plasmas with liquids and biological systems. Methods to characterize the plasma generated reactive species from plasma-, gas- and liquid phase and their biological effects will be presented. The diagnostic spectrum ranges from absorption/emission/laser spectroscopy and molecular beam mass spectrometry to electron paramagnetic resonance spectroscopy and cell biological diagnostic techniques. Concluding, a presentation will be given of the comprehensive approach to plasma medicine in Greifswald where the applied and clinical research of the Campus PlasmaMed association is combined with the fundamental research at plasmatis center.

  14. Langmuir probe diagnostics of an atmospheric pressure, vortex-stabilized nitrogen plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Prevosto, L.; Mancinelli, B. R. [Grupo de Descargas Electricas, Departamento Ingenieria Electromecanica, Facultad Regional Venado Tuerto (UTN), Laprida 651, (2600) Venado Tuerto, Santa Fe (Argentina); Kelly, H. [Grupo de Descargas Electricas, Departamento Ingenieria Electromecanica, Facultad Regional Venado Tuerto (UTN), Laprida 651, (2600) Venado Tuerto, Santa Fe (Argentina) and Instituto de Fisica del Plasma (CONICET), Departamento de Fisica, Facultad de Ciencias Exactas y Naturales UBA Ciudad Universitaria Pab. I, (1428) Buenos Aires (Argentina)

    2012-09-15

    Langmuir probe measurements in an atmospheric pressure direct current (dc) plasma jet are reported. Sweeping probes were used. The experiment was carried out using a dc non-transferred arc torch with a rod-type cathode and an anode of 5 mm diameter. The torch was operated at a nominal power level of 15 kW with a nitrogen flow rate of 25 Nl min{sup -1}. A flat ion saturation region was found in the current-voltage curve of the probe. The ion saturation current to a cylindrical probe in a high-pressure non local thermal equilibrium (LTE) plasma was modeled. Thermal effects and ionization/recombination processes inside the probe perturbed region were taken into account. Averaged radial profiles of the electron and heavy particle temperatures as well as the electron density were obtained. An electron temperature around 11 000 K, a heavy particle temperature around 9500 K and an electron density of about 4 Multiplication-Sign 10{sup 22} m{sup -3}, were found at the jet centre at 3.5 mm downstream from the torch exit. Large deviations from kinetic equilibrium were found throughout the plasma jet. The electron and heavy particle temperature profiles showed good agreement with those reported in the literature by using spectroscopic techniques. It was also found that the temperature radial profile based on LTE was very close to that of the electrons. The calculations have shown that this method is particularly useful for studying spraying-type plasma jets characterized by electron temperatures in the range 9000-14 000 K.

  15. 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}.

  16. Solvated electrons at the atmospheric pressure plasma-water anodic interface

    Science.gov (United States)

    Gopalakrishnan, R.; Kawamura, E.; Lichtenberg, A. J.; Lieberman, M. A.; Graves, D. B.

    2016-07-01

    We present results from a particle-in-cell/Monte Carlo model of a dc discharge in argon at atmospheric pressure coupled with a fluid model of an aqueous electrolyte acting as anode to the plasma. The coupled models reveal the structure of the plasma-electrolyte interface and near-surface region, with a special emphasis on solvated or hydrated electrons. Results from the coupled models are in generally good agreement with the experimental results of Rumbach et al (2016 Nat. Commun. 6 7248). Electrons injected from the plasma into the water are solvated, then lost by reaction with water within about 10-20 nm from the surface. The major reaction products are OH- and H2. The solvated electron density profile is controlled by the injected electron current density and subsequent reactions with water, and is relatively independent of the external plasma electric field and the salt concentration in the aqueous electrolyte. Simulations of the effects of added scavenger compounds (H2O2, \\text{NO}2- , \\text{NO}2- and H+) on near-surface solvated electron density generally match the experimental results. The generation of near-surface OH- following electron-water decomposition in the presence of bulk acid creates a highly basic region (pH ~ 11) very near the surface. In the presence of bulk solution acidity, pH can vary from a very acidic pH 2 away from the surface to a very basic pH 11 over a distance of ~200 nm. High near-surface gradients in aqueous solution properties could strongly affect plasma-liquid applications and challenge theoretical understanding of this complex region.

  17. Effect of sheath gas in atmospheric-pressure plasma jet for potato sprouting suppression

    Science.gov (United States)

    Nishiyama, S.; Monma, M.; Sasaki, K.

    2016-09-01

    Recently, low-temperature atmospheric-pressure plasma jets (APPJs) attract much interest for medical and agricultural applications. We try to apply APPJs for the suppression of potato sprouting in the long-term storage. In this study, we investigated the effect of sheath gas in APPJ on the suppression efficiency of the potato sprouting. Our APPJ was composed of an insulated thin wire electrode, a glass tube, a grounded electrode which was wound on the glass tube, and a sheath gas nozzle which was attached at the end of the glass tube. The wire electrode was connected to a rectangular-waveform power supply at a frequency of 3 kHz and a voltage of +/- 7 kV. Helium was fed through the glass tube, while we tested dry nitrogen, humid nitrogen, and oxygen as the sheath gas. Eyes of potatoes were irradiated by APPJ for 60 seconds. The sprouting probability was evaluated at two weeks after the plasma irradiation. The sprouting probability was 28% when we employed no sheath gases, whereas an improved probability of 10% was obtained when we applied dry nitrogen as the sheath gas. Optical emission spectroscopy was carried out to diagnose the plasma jet. It was suggested that reactive species originated from nitrogen worked for the efficient suppression of the potato sprouting.

  18. Influence of discharge and jet flow coupling on atmospheric pressure plasma homogeneity

    Science.gov (United States)

    Nizard, H.; Gaudy, T.; Toutant, A.; Iacono, J.; Descamps, P.; Leempoel, P.; Massines, F.

    2015-10-01

    The effect of flow dynamics on the discharge mode is studied in order to design a technical solution for thin film coating on large surfaces. The configuration consists in two atmospheric pressure helium plasma jets impacting a surface and confined in a tube. This system operates in open air. It has been studied by short exposure time pictures, current and voltage measurements, optical emission spectroscopy, schlieren flow visualization and computational fluid dynamics. Two discharge regimes directly connected to the gas flow dynamic have been pointed out. One is localized from the point electrodes to the surface; the other one entirely fills the confinement tube. A correlation between air intake inside the confinement tube and the discharge mode has been highlighted. Indeed, the discharge only develops in helium and the air intake confines the helium jets in volumes smaller than the confinement tube. The air intake is determined by the gas flow rate and the distance from the tube bottom to the substrate surface, parameters which have been linked to the change from laminar to turbulent flow. Finally, the understanding of flow dynamics and discharge plasma coupling allowed the design of a technical solution favoring plasma homogeneity for large surface treatment.

  19. Atmospheric pressure cold plasma treatment of cellulose based fillers for wood plastic composites

    Science.gov (United States)

    Lekobou, William; Englund, Karl; Pedrow, Patrick; Scudiero, Louis

    2011-10-01

    The main challenge of wood plastic composites (WPC) resides in the low interfacial adhesion due to incompatibility between the cellulose based filler that has a polar surface and most common matrixes, polyolefins which are non-polar. Plasma treatment is a promising technique for surface modification and its implementation into the processing of WPC would provide this industry with a versatile and nearly environmentally benign manufacturing tool. Our investigation aims at designing a cold atmospheric pressure plasma reactor for coating fillers with a hydrophobic material prior to compounding with the matrix. Deposition was achieved with our reactor that includes an array of high voltage needles, a grounded metal mesh, Ar as carrier gas and C2H2 as the precursor molecule. Parameters studied have included gas feed rates and applied voltage; FTIR, ESCA, AFM and SEM imaging were used for film diagnostics. We will also report on deposition rate and its dependence on radial and axial position as well as the effects of plasma-polymerized acetylene on the surface free energy of cellulose based substrates.

  20. Surface conductivity dependent dynamic behaviour of an ultrafine atmospheric pressure plasma jet for microscale surface processing

    Science.gov (United States)

    Abuzairi, Tomy; Okada, Mitsuru; Bhattacharjee, Sudeep; Nagatsu, Masaaki

    2016-12-01

    An experimental study on the dynamic behaviour of microcapillary atmospheric pressure plasma jets (APPJs) with 5 μm tip size for surfaces of different conductivity is reported. Electrical and spatio-temporal characteristics of the APPJs are monitored using high voltage probe, current monitor and high speed intensified charge couple device camera. From these experimental results, we presented a simple model to understand the electrical discharge characteristics of the capillary APPJs with double electrodes, and estimated the velocity of the ionization fronts in the jet and the electron density to be 3.5-4.2 km/s and 2-7 × 1017 m-3. By analyzing the dynamics of the microcapillary APPJs for different substrate materials, it was found that the surface irradiation area strongly depended on the substrate conductivity and permittivity, especially in the case of polymer-like substrate, surface irradiation area was significantly broadened probably due to the repelling behaviour of the plasma jets from the accumulated electrical charges on the polymer surface. The effect of applying a substrate bias in the range from -900 V to +900 V on the plasma irradiation onto the substrates was also investigated. From the knowledge of the present results, it is helpful for choosing the substrate materials for microscale surface modification.

  1. Photons and particles emitted from cold atmospheric-pressure plasma inactivate bacteria and biomolecules independently and synergistically.

    Science.gov (United States)

    Lackmann, Jan-Wilm; Schneider, Simon; Edengeiser, Eugen; Jarzina, Fabian; Brinckmann, Steffen; Steinborn, Elena; Havenith, Martina; Benedikt, Jan; Bandow, Julia E

    2013-12-06

    Cold atmospheric-pressure plasmas are currently in use in medicine as surgical tools and are being evaluated for new applications, including wound treatment and cosmetic care. The disinfecting properties of plasmas are of particular interest, given the threat of antibiotic resistance to modern medicine. Plasma effluents comprise (V)UV photons and various reactive particles, such as accelerated ions and radicals, that modify biomolecules; however, a full understanding of the molecular mechanisms that underlie plasma-based disinfection has been lacking. Here, we investigate the antibacterial mechanisms of plasma, including the separate, additive and synergistic effects of plasma-generated (V)UV photons and particles at the cellular and molecular levels. Using scanning electron microscopy, we show that plasma-emitted particles cause physical damage to the cell envelope, whereas UV radiation does not. The lethal effects of the plasma effluent exceed the zone of physical damage. We demonstrate that both plasma-generated particles and (V)UV photons modify DNA nucleobases. The particles also induce breaks in the DNA backbone. The plasma effluent, and particularly the plasma-generated particles, also rapidly inactivate proteins in the cellular milieu. Thus, in addition to physical damage to the cellular envelope, modifications to DNA and proteins contribute to the bactericidal properties of cold atmospheric-pressure plasma.

  2. Antifouling Transparent ZnO Thin Films Fabricated by Atmospheric Pressure Cold Plasma Deposition

    Science.gov (United States)

    Suzaki, Yoshifumi; Du, Jinlong; Yuji, Toshifumi; Miyagawa, Hayato; Ogawa, Kazufumi

    2015-09-01

    One problem with outdoor-mounted solar panels is that power generation efficiency is reduced by face plate dirt; a problem with electronic touch panels is the deterioration of screen visibility caused by finger grease stains. To solve these problems, we should fabricate antifouling surfaces which have superhydrophobic and oil-repellent properties without spoiling the transparency of the transparent substrate. In this study, an antifouling surface with both superhydrophobicity and oil-repellency was fabricated on a glass substrate by forming a fractal microstructure. The fractal microstructure was constituted of transparent silica particles 100 nm in diameter and transparent zinc-oxide columns grown on silica particles through atmospheric pressure cold plasma deposition; the sample surface was coated with a chemically adsorbed monomolecular layer. Samples were obtained which had a superhydrophobic property (with a water droplet contact angle of more than 150°) and a high average transmittance of about 90% (with wavelengths ranging from 400 nm to 780 nm).

  3. Plasma sterilization of polyethylene terephthalate bottles by pulsed corona discharge at atmospheric pressure.

    Science.gov (United States)

    Masaoka, Satoshi

    2007-06-01

    A pulsed power supply was used to generate a corona discharge on a polyethylene terephthalate bottle, to conduct plasma sterilization at atmospheric pressure. Before generating such a discharge, minute quantities of water were attached to the inner surface of the bottle and to the surface of a high voltage (HV) electrode inserted into the bottle. Next, high-voltage pulses of electricity were discharged between electrodes for 6.0s, while rotating the bottle. The resulting spore log reduction values of Bacillus subtilis and Aspergillus niger on the inner surface of the bottle were 5.5 and 6 or higher, respectively, and those on the HV electrode surface were each 6 or higher for both strains. The presence of the by-products gaseous ozone, hydrogen peroxide, and nitric ions resulting from the electrical discharge was confirmed.

  4. Surface Modification of Polyethylene (PE) Films Using Dielectric Barrier Discharge Plasma at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    WANG Kun; LI Jian; REN Chunsheng; WANG Dezhen; WANG Younian

    2008-01-01

    Modification of the surface properties of polyethylene (PE) films is studied using air dielectric barrier discharge at atmospheric pressure. The treated samples are examined by water contact angle measurements, Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). With the increase in treating time, the water contact angle changes from 93.2° before treatment to a minimum of 53.3° after a treatment for 50 s. Both ATR and XPS results show some oxidized" species are introduced into the sample surface by the plasma treatment and the tendency of the water contact angle with the treating time is the same as that of oxygen concentration on the treated sample surface. SEM result shows the surface roughness of PE samples increases with the treatment time increasing.

  5. Inactivation of Escherichia coli ATCC 11775 in fresh produce using atmospheric pressure cold plasma

    Science.gov (United States)

    Bermudez-Aguirre, Daniela; Wemlinger, Erik; Barbosa-Canovas, Gustavo; Pedrow, Patrick; Garcia-Perez, Manuel

    2011-10-01

    Food-borne outbreaks are associated with the presence of pathogenic bacteria in food products such as fresh produce. One of the target microorganisms is Escherichia coli which exhibits resistance to being inactivated with conventional disinfection methods for vegetables. Atmospheric pressure cold plasma (APCP) was tested to disinfect three vegetables with challenge surfaces, lettuce, carrots and tomatoes. The produce was inoculated with the bacteria to reach an initial microbial concentration of 107 cfu/g. Vegetables were initially exposed to the APCP discharges from a needle array at 5.7 kV RMS in argon, processing times of 0.5, 3 and 5 min. Initial results indicate that microbial decontamination is effective on the lettuce (1.2 log reduction) when compared with other vegetables. To claim disinfection, a 3 log reduction or more is needed, which makes APCP treatment very promising technology for decontamination of produce. We propose that with method refinements full disinfection can be achieved using APCP.

  6. Observation of the Emission Spectra of an Atmospheric Pressure Radio-frequency Plasma Jet

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    An atmospheric pressure plasma jet (APPJ) using radio-frequency (13.56 MHz)power has been developed to produce homogeneous glow discharge at low temperature. With optical emission spectroscopy, we observed the excited species (atomic helium, atomic oxygen and metastable oxygen) generated in this APPJ and their dependence on gas composition ratio and RF power. O and O2(b1∑g+) are found in the effluent outside the jet by measuring the emission spectra of effluent perpendicular to the jet. An interesting phenomenon is found that there is an abnormal increase of O emission intensity (777.4 nm) between 10 mm and 40 mm away from the nozzle. This observation result is very helpful in practical operation.

  7. Cell immobilization on polymer by air atmospheric pressure plasma jet treatment

    Science.gov (United States)

    Lee, Jung-Hwan; Kwon, Jae-Sung; Om, Ji-yeon; Kim, Yong-Hee; Choi, Eun-Ha; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2014-08-01

    The study of cell immobilization on delicate polymer by an air atmospheric pressure plasma jet (AAPPJ) is required for its medical application. The aim of this study was to evaluate whether AAPPJ treatment induce cell immobilization effect on delicate polymers without significant change of surface roughness by AAPPJ treatment. After surface roughness, dynamic contact angle, and chemical characteristics were investigated, the immobilization effect was evaluated with the mouse fibroblast L929 cell line. Surface roughness change was not observed (P > 0.05) in either delicate dental wax or polystyrene plate (PSP) as advancing and receding contact angles significantly decreased (P < 0.05), thanks to decreased hydrocarbon and formation of oxygen-related functional groups in treated PSP. Adherent L929 cells with elongated morphology were found in treated PSP along with the formation of immobilization markers vinculin and actin cytoskeleton. Increased PTK2 gene expression upregulated these markers on treated PSP.

  8. All-vanadium redox flow batteries with graphite felt electrodes treated by atmospheric pressure plasma jets

    Science.gov (United States)

    Chen, Jian-Zhang; Liao, Wei-Yang; Hsieh, Wen-Yen; Hsu, Cheng-Che; Chen, Yong-Song

    2015-01-01

    Graphite felts modified with atmospheric pressure plasma jets (APPJs) are applied as electrodes in an all-vanadium redox flow battery (VRFB). APPJ flow penetrates deeply into the graphite felt, improving significantly the wettability of the graphite felt inside out and, thereby, enhancing graphite fiber-electrolyte contact during battery operation. The energy efficiency of a VRFB was improved from 62% (untreated) to 76% (APPJ-treated with the scan mode) at a current density of 80 mA cm-2, an improvement of 22%. The efficiency improvement is attributed to the oxygen-containing groups and nitrogen doping introduced by N2 APPJs on the fiber surfaces of graphite felt, both of which enhance electrochemical reactivity.

  9. Optical properties of the atmospheric pressure helium plasma jet generated by alternative current (a.c.) power supply

    Science.gov (United States)

    Ilik, Erkan; Akan, Tamer

    2016-05-01

    In this work, an atmospheric pressure plasma jet (APPJ) was produced to generate cold flowing post-discharge plasma of pure helium gas. The main aim of this study was to generate cold flowing APPJ of pure helium gas and to determine how their optical emission spectrum change influences varying different flow rates. Lengths of early, middle, and late post-discharge plasma (jet) regions and their fluctuations were determined, respectively. Then, ignition condition dependence of the post-discharge plasma for flow rate was specified at a constant voltage. Spectroscopic studies of an atmospheric pressure plasma jet of helium were presented via analyzing OH, N2, N2+, oxygen, and helium intensities for various flow rates.

  10. Online diagnosis of electron excitation temperature in CH4+H2 discharge plasma at atmospheric pressure by optical emission spectra

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Methane coupling under low temperature plasmas at atmospheric pressure is a green process by use of renewable sources of energy. In this study, CH4+H2 dis- charge plasma was on-line diagnosed by optical emission spectra so as to char- acterize the discharge system and to do spade work for the optimization of the technical parameters for future commercial production of methane coupling under plasmas. The study was focused on a calculation method for the online diagnosis of the electron excitation temperature in CH4+H2 discharge plasma at atmospheric pressure. The diagnostic method is easy, efficient and fairly precise. A serious er- ror in a literature was corrected during the reasoning of its series of equations formerly used to calculate electron temperatures in plasmas.

  11. Online diagnosis of electron excitation temperature in CH4+H2 discharge plasma at atmospheric pressure by optical emission spectra

    Institute of Scientific and Technical Information of China (English)

    CUI JinHua; XU ZhenFeng; ZHANG JiaLiang; NIE QiuYue; XU GenHui; REN LongLiang

    2008-01-01

    Methane coupling under low temperature plasmas at atmospheric pressure is a green process by use of renewable sources of energy.In this study,CH4+H2 dis-charge plasma was on-line diagnosed by optical emission spectra so as to char-acterize the discharge system and to do spade work for the optimization of the technical parameters for future commercial production of methane coupling under plasmas.The study was focused on a calculation method for the online diagnosis of the electron excitation temperature in CH4+H2 discharge plasma at atmospheric pressure.The diagnostic method is easy,efficient and fairly precise.A serious er-ror in a literature was corrected during the reasoning of its series of equations formerly used to calculate electron temperatures in plasmas.

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

    Science.gov (United States)

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

    2016-02-01

    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

  13. Influence of excited state spatial distributions on plasma diagnostics: Atmospheric pressure laser-induced He-H2 plasma

    Science.gov (United States)

    Monfared, Shabnam K.; Hüwel, Lutz

    2012-10-01

    Atmospheric pressure plasmas in helium-hydrogen mixtures with H2 molar concentrations ranging from 0.13% to 19.7% were investigated at times from 1 to 25 μs after formation by a Q-switched Nd:YAG laser. Spatially integrated electron density values are obtained using time resolved optical emission spectroscopic techniques. Depending on mixture concentration and delay time, electron densities vary from almost 1017 cm-3 to about 1014 cm-3. Helium based results agree reasonably well with each other, as do values extracted from the Hα and Hβ emission lines. However, in particular for delays up to about 7 μs and in mixtures with less than 1% hydrogen, large discrepancies are observed between results obtained from the two species. Differences decrease with increasing hydrogen partial pressure and/or increasing delay time. In mixtures with molecular hydrogen fraction of 7% or more, all methods yield electron densities that are in good agreement. These findings seemingly contradict the well-established idea that addition of small amounts of hydrogen for diagnostic purposes does not perturb the plasma. Using Abel inversion analysis of the experimental data and a semi-empirical numerical model, we demonstrate that the major part of the detected discrepancies can be traced to differences in the spatial distributions of excited helium and hydrogen neutrals. The model yields spatially resolved emission intensities and electron density profiles that are in qualitative agreement with experiment. For the test case of a 1% H2 mixture at 5 μs delay, our model suggests that high electron temperatures cause an elevated degree of ionization and thus a reduction of excited hydrogen concentration relative to that of helium near the plasma center. As a result, spatially integrated analysis of hydrogen emission lines leads to oversampling of the plasma perimeter and thus to lower electron density values compared to those obtained from helium lines.

  14. Temperature Dependence of Nitro-Quenching by Atmospheric-Pressure Plasma

    Science.gov (United States)

    Mitani, Masaki; Ichiki, Ryuta; Iwakiri, Yutaro; Akamine, Shuichi; Kanazawa, Seiji

    2015-09-01

    A lot of techniques exist as the hardening method of steels, such as nitriding, carburizing and quenching. However, low-alloy steels cannot be hardened by nitriding because hardening by nitriding requires nitride precipitates of special alloy elements such as rare metals. Recently, nitro-quenching (NQ) was developed as a new hardening process, where nitrogen invokes martensitic transformation instead of carbon. NQ is adaptable to hardening low-alloy steels because it does not require alloy elements. In industrial NQ, nitrogen diffusion into steel surface is operated in high temperature ammonia gas. As a new technology, we have developed surface hardening of low-alloy steel by NQ using an atmospheric-pressure plasma. Here the pulsed-arc plasma jet with nitrogen/hydrogen gas mixture is sprayed onto steel surface and then water quench the sample. As a result, the surface of low-alloy steel was partially hardened up to 800 Hv by producing iron-nitrogen martensite. However, the hardness profile is considerably non-uniform. We found that the non-uniform hardness profile can be controlled by changing the treatment gap, the gap between the jet nozzle and the sample surface. Eventually, we succeeded in hardening a targeted part of steel by optimizing the treatment gap. Moreover, we propose the mechanism of non-uniform hardness.

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

    Indian Academy of Sciences (India)

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

    2013-03-01

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

  16. Discharge processes and an electrical model of atmospheric pressure plasma jets in argon

    Science.gov (United States)

    Fang, Zhi; Shao, Tao; Yang, Jing; Zhang, Cheng

    2016-01-01

    In this paper, an atmospheric pressure plasma discharge in argon was generated using a needle-to-ring electrode configuration driven by a sinusoidal excitation voltage. The electric discharge processes and discharge characteristics were investigated by inspecting the voltage-current waveforms, Lissajous curves and lighting emission images. The change in discharge mode with applied voltage amplitude was studied and characterised, and three modes of corona discharge, dielectric barrier discharge (DBD) and jet discharge were identified, which appeared in turn with increasing applied voltage and can be distinguished clearly from the measured voltage-current waveforms, light-emission images and the changing gradient of discharge power with applied voltage. Based on the experimental results and discharge mechanism analysis, an equivalent electrical model and the corresponding equivalent circuit for characterising the whole discharge processes accurately was proposed, and the three discharge stages were characterised separately. A voltage-controlled current source (VCCS) associated with a resistance and a capacitance were used to represent the DBD stage, and the plasma plume and corona discharge were modelled by a variable capacitor in series with a variable resistor. Other factors that can influence the discharge, such as lead and stray capacitance values of the circuit, were also considered in the proposed model. Contribution to the Topical Issue "Recent Breakthroughs in Microplasma Science and Technology", edited by Kurt Becker, Jose Lopez, David Staack, Klaus-Dieter Weltmann and Wei Dong Zhu.

  17. Back corona enhanced organic film deposition inside an Atmospheric Pressure Weakly Ionized Plasma reactor

    Science.gov (United States)

    Islam, Rokibul; Xie, Shuzheng; Englund, Karl; Pedrow, Patrick

    2014-10-01

    A grounded screen with short needle-like protrusions has been designed to generate back corona in an Atmospheric Pressure Weakly Ionized Plasma (APWIP) reactor. The grounded screen with protrusions is placed downstream at a variable gap length from an array of needles that is energized with 60 Hz high voltage. The excitation voltage is in the range 0--10 kV RMS and the feed gas mixture consists of argon and acetylene. A Lecroy 9350AL 500 MHz digital oscilloscope is used to monitor the reactor voltage and current using a resistive voltage divider and a current viewing resistor, respectively. The current signal contains many positive and negative current pulses associated with corona discharge. Analysis of the current signal shows asymmetry between positive and negative corona discharge currents. Photographs show substantial back corona generated near the tips of the protrusions situated at the grounded screen. The back corona activates via bond scission acetylene radicals that are transported downstream to form a plasma-polymerized film on a substrate positioned downstream from the grounded screen. The oscillograms will be used to generate corona mode maps that show the nature of the corona discharge as a function of gap spacing, applied voltage and many other reactor parameters.

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

    KAUST Repository

    Casey, Tiernan A.

    2016-10-21

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

  19. Formation and characteristics of patterns in atmospheric-pressure radio-frequency dielectric barrier discharge plasma

    Science.gov (United States)

    Yang, Lizhen; Liu, Zhongwei; Mao, Zhiguo; Li, Sen; Chen, Qiang

    2017-01-01

    The patterns in radio-frequency dielectric barrier discharge (RF DBD) are studied at atmospheric pressure of argon (Ar) or helium (He) mixed with nitrogen (N2) gas. When a small amount of N2 is mixed with He or Ar gas, discharge patterns are formed. In a N2/He gas mixture, besides the filament discharge that forms patterns, a glow background discharge is also observed, whereas only the filament discharge forms patterns in a N2/Ar gas mixture. The resolution of the hexagonal pattern as a function of applied power and gas flow rate is then explored. On the basis of spatial-temporal images taken using an intensified charge-coupled device (ICCD), we find that there is no interleaving of two transient hexagon sublattices in N2/Ar or N2/He plasma in RF DBD patterns, which are totally different from those in which surface charges dominated in the mid-frequency DBD plasma. This supports our hypothesis that the bulk charges dominate the pattern formation in RF DBD.

  20. Comparative study of non-thermal atmospheric pressure discharge plasmas for life science applications

    Science.gov (United States)

    Koga, Kazunori; Katayama, Ryu; Sarinont, Thapanut; Seo, Hyunwoong; Itagaki, Naho; Attri, Pankaj; Leal-Quiros, Edbertho; Tanaka, Akiyo; Shiratani, Masaharu

    2016-09-01

    We are comparing several non-thermal atmospheric pressure discharge plasmas for life science applications. Here we measured discharge period dependence of pH value and 750 nm absorbance of KI-starch solution of deionized water after plasma irradiation with two discharge devices; a dielectric barrier discharge (DBD) jet device and a scalable DBD device. The pH and the absorbance of KI-starch solution are useful indicator of their oxidizability. We have obtained a map of the absorbance and proton concentration [H+] which is deduced from pH value. For the scalable DBD, the range of the absorbance is between 0.7 and 1.3 and that of [H+] is between 10-7 and 10-5 mol/L. For the DBD jet, the range of the absorbance and [H+] are 2.0-3.2 and 10-4-10-3 mol/L, respectively. Measured data for both devices shows same tendency in the map, while the range of values for the scalable DBD is smaller than that for the DBD jet. The results indicate the oxidazability for the scalable DBD is much weaker than that for the DBD jet.

  1. Diamond synthesis at atmospheric pressure by microwave capillary plasma chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hemawan, Kadek W.; Gou, Huiyang; Hemley, Russell J. [Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Rd., NW, Washington, DC 20015 (United States)

    2015-11-02

    Polycrystalline diamond has been synthesized on silicon substrates at atmospheric pressure, using a microwave capillary plasma chemical vapor deposition technique. The CH{sub 4}/Ar plasma was generated inside of quartz capillary tubes using 2.45 GHz microwave excitation without adding H{sub 2} into the deposition gas chemistry. Electronically excited species of CN, C{sub 2}, Ar, N{sub 2}, CH, H{sub β}, and H{sub α} were observed in the emission spectra. Raman measurements of deposited material indicate the formation of well-crystallized diamond, as evidenced by the sharp T{sub 2g} phonon at 1333 cm{sup −1} peak relative to the Raman features of graphitic carbon. Field emission scanning electron microscopy images reveal that, depending on the growth conditions, the carbon microstructures of grown films exhibit “coral” and “cauliflower-like” morphologies or well-facetted diamond crystals with grain sizes ranging from 100 nm to 10 μm.

  2. SnO2/CNT nanocomposite supercapacitors fabricated using scanning atmospheric-pressure plasma jets

    Science.gov (United States)

    Xu, Chang-Han; Chiu, Yi-Fan; Yeh, Po-Wei; Chen, Jian-Zhang

    2016-08-01

    SnO2/CNT electrodes for supercapacitors are fabricated by first screen-printing pastes containing SnO2 nanoparticles and CNTs on carbon cloth, following which nitrogen atmospheric pressure plasma jet (APPJ) sintering is performed at various APPJ scan rates. The APPJ scan rates change the time intervals for which the reactive plasma species and the heat of the nitrogen APPJs influence the designated sintering spot on the carbon cloth, resulting in APPJ-sintered SnO2/CNT nanocomposites with different properties. The water contact angle decreases with the APPJ scan rate. The improved wettability can facilitate the penetration of the electrolyte into the nanopores of the SnO2/CNT nanocomposites, thereby improving the charge storage and specific capacitance of the supercapacitors. Among the three tested APPJ scan rates, 1.5, 3, and 6 mm s-1, the SnO2/CNT supercapacitor sintered by APPJ under the lowest APPJ scan rate of 1.5 mm s-1 shows the best specific capacitance of ˜90 F g-1 as evaluated by cyclic voltammetry under a potential scan rate of 2 mV s-1. A high APPJ scan rate may result in low degree of materials activation and sintering, leading to poorer performance of SnO2/CNT supercapacitors. The results suggest the feasibility of an APPJ roll-to-roll process for the fabrication of SnO2/CNT nanocomposite supercapacitors.

  3. Syngas production from tar reforming by microwave plasma jet at atmospheric pressure: power supplied influence

    Science.gov (United States)

    de Souza Medeiros, Henrique; Justiniano, Lucas S.; Gomes, Marcelo P.; Soares da Silva Sobrinho, Argemiro; Petraconi Filho, Gilberto

    2013-09-01

    Now a day, scientific community is searching for new fuels able to replace fossil fuels with economic and environment gains and biofuel play a relevant rule, mainly for the transport sector. A major process to obtaining such type of renewable resource is biomass gasification. This process has as product a gas mixture containing CO, CH4, and H2 which is named synthesis gas (syngas). However, an undesirable high molecular organic species denominated tar are also produced in this process which must be removed. In this work, results of syngas production via tar reforming in the atmospheric pressure microwave discharge having as parameter the power supply. Argon, (argon + ethanol), and (argon + tar solution) plasma jet were produced by different values of power supplied (from 0.5 KW to 1.5 KW). The plasma compounds were investigated by optical spectroscopy to each power and gas composition. The main species observed in the spectrum are Ar, CN, OII, OIV, OH, H2, H(beta), CO2, CO, and SIII. This last one came from tar. The best value of the power applied to syngas production from tar reforming was verified between 1.0 KW and 1.2 KW. We thank the following institutions for financial support: CNPq, CAPES, and FAPESP.

  4. Glyphosate contaminated soil remediation by atmospheric pressure dielectric barrier discharge plasma and its residual toxicity evaluation.

    Science.gov (United States)

    Wang, Tiecheng; Ren, Jingyu; Qu, Guangzhou; Liang, Dongli; Hu, Shibin

    2016-12-15

    Glyphosate was one of the most widely used herbicides in the world. Remediation of glyphosate-contaminated soil was conducted using atmospheric pressure dielectric barrier discharge (DBD) plasma. The feasibility of glyphosate degradation in soil was explored, and the soil leachate toxicity after remediation was assessed via a seed germination test. The experimental results showed that approximately 93.9% of glyphosate was degraded within 45min of DBD plasma treatment with an energy yield of 0.47gkWh(-1), and the degradation process fitted the first-order kinetic model. Increasing the discharge voltage and decreasing the organic matter content of the soil were both found to facilitate glyphosate degradation. There existed appropriate soil moisture to realize high glyphosate degradation efficiency. Glyphosate mineralization was confirmed by changes of total organic carbon (TOC), chemical oxygen demand (COD), PO4(3-) and NO3(-). The degradation intermediates including glycine, aminomethylphosphonic acid, acetic acid, formic acid, PO4(3-) and NO3(-), CO2 and CO were observed. A possible pathway for glyphosate degradation in the soil using this system was proposed. Based on the soil leachate toxicity test using wheat seed germination, the soil did not exhibit any hazardous effects following high-efficiency glyphosate degradation.

  5. Plasma polymers deposited in atmospheric pressure dielectric barrier discharges: Influence of process parameters on film properties

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, Katja, E-mail: k.fricke@inp-greifswald.de [Leibniz Institute for Plasma Science and Technology e.V. (INP Greifswald), Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Girard-Lauriault, Pierre-Luc [Plasma Processing Laboratory, Department of Chemical Engineering, McGill University, 3610 rue University, Montreal, QC H3A 0C5 (Canada); Weltmann, Klaus-Dieter [Leibniz Institute for Plasma Science and Technology e.V. (INP Greifswald), Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Wertheimer, Michael R. [Department of Engineering Physics, École Polytechnique de Montréal, Box 6079, Station Centre-Ville, Montreal, QC H3C 3A7 (Canada)

    2016-03-31

    We present results on the deposition of plasma polymer (PP) films in a dielectric barrier discharge system fed with mixtures of argon or nitrogen carrier gas plus different hydrocarbon precursors, where the latter possess different carbon-to-hydrogen ratios: CH{sub 4} < C{sub 2}H{sub 6} < C{sub 2}H{sub 4} = C{sub 3}H{sub 6} < C{sub 2}H{sub 2}. The influence of precursor gas mixture and flow rate, excitation frequency, and absorbed power on PP film compositions and properties has been investigated. The discharge was characterized by electrical measurements, while the chemical compositions and structures of coatings were analysed by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, total combustion, and elastic recoil detection analyses, the latter two for determining carbon-to-hydrogen ratios. Scanning electron microscopy was used to study the coatings' morphology, and profilometry for evaluating deposition rates. - Highlights: • Atmospheric pressure DBD is used to deposit organic hydrocarbon films. • High deposition rates can be achieved by varying the power and/or gas mixture ratio. • Process parameters affect the films' surface chemical composition and morphology. • Deposited films are not soluble in aqueous environment. • No delamination of coatings produced from argon plasma.

  6. Experimental investigation of photoresist etching by kHz AC atmospheric pressure plasma jet

    Science.gov (United States)

    Wang, Lijun; Zheng, Yashuang; Wu, Chen; Jia, Shenli

    2016-11-01

    In this study, the mechanism of the photoresist (PR) etching by means of a kHz AC atmospheric pressure plasma jet (APPJ) is investigated. The scanning electron (SEM) and the polarizing microscope are used to perform the surface analysis, and the mechanical profilometry is applied to diagnose the etch rate. The results show that granulated structure with numerous microparticles appears at the substrate surface after APPJ treatment, and the etch rate in the etch center is the fastest and gradually slows down to the edge of etch region. In addition, the pin-ring electrode APPJ has the highest etch rate at but easy to damage the Si wafer, the double-ring APPJ is the most stable but requires long time to achieve the ideal etch result, and the etch rate and the etch result of the multi-electrode APPJ fall in between. Ar APPJ had much higher PR etch rate and more irregular etch trace than He APPJ. It is speculated that Ar APPJ is more energetic and effective in transferring reactive species to the PR surface. It is also observed that the effective etch area initially increases and then decreases as plasma jet outlet to the PR surface distance increases.

  7. Comparison of the characteristics of atmospheric pressure plasma jets using different working gases and applications to plasma-cancer cell interactions

    Directory of Open Access Journals (Sweden)

    Hea Min Joh

    2013-09-01

    Full Text Available Atmospheric pressure plasma jets employing nitrogen, helium, or argon gases driven by low-frequency (several tens of kilohertz ac voltage and pulsed dc voltage were fabricated and characterized. The changes in discharge current, optical emission intensities from reactive radicals, gas temperature, and plume length of plasma jets with the control parameters were measured and compared. The control parameters include applied voltage, working gas, and gas flow rate. As an application to plasma-cancer cell interactions, the effects of atmospheric pressure plasma jet on the morphology and intracellular reactive oxygen species (ROS level of human lung adenocarcinoma cell (A549 and human bladder cancer cell (EJ were explored. The experimental results show that the plasma can effectively control the intracellular concentrations of ROS. Although there exist slight differences in the production of ROS, helium, argon, or nitrogen plasma jets are found to be useful in enhancing the intracellular ROS concentrations in cancer cells.

  8. The influence of electrode configuration on light emission profiles and electrical characteristics of an atmospheric-pressure plasma jet

    Science.gov (United States)

    Maletić, Dejan; Puač, Nevena; Malović, Gordana; Đorđević, Antonije; Petrović, Zoran Lj

    2017-04-01

    In this paper we focus on the influence of the type of electrodes, their dimensions and inter-electrode gap on the formation of a helium plasma jet. Plasma emission profiles are recorded by an ICCD camera simultaneously with volt–ampere characteristics for three different copper electrode configurations. The delivered power was up to 6.5 W, but it may be set and controlled to 0.1 W. This study shows how the electrode configuration shapes and controls temporal and spatial plasma development as well as electrical characteristics of an atmospheric pressure plasma jet. It is shown that, in our system, the width of the grounded electrode has no significant influence on the formation and properties of pulsed atmospheric-pressure streamers (PAPS) outside the tube, while the width of the powered electrode is crucial in their formation.

  9. Comparison of Sterilizing Effect of Nonequilibrium Atmospheric-Pressure He/O2 and Ar/O2 Plasma Jets

    Science.gov (United States)

    Li, Shouzhe; Lim, Jinpyo

    2008-02-01

    The sterilizing effect of the non-equilibrium atmospheric pressure plasma jet by applying it to the Bacillus subtilis spores is invesigated. A stable glow discharge in argon or helium gas fed with active gas (oxygen), was generated in the coaxial cylindrical reactor powered by the radio-frequency power supply at atmospheric pressure. The experimental results indicated that the efficiency of killing spores by making use of an Ar/O2 plasma jet was much better than with a He/O2 plasma jet. The decimal reduction value of Ar/O2 and He/O2 plasma jets under the same experimental conditions was 4.5 seconds and 125 seconds, respectively. It was found that there exists an optimum oxygen concentration for a certain input power, at which the sterilization efficiency reaches a maximum value. It is believed that the oxygen radicals are generated most efficiently under this optimum condition.

  10. Comparison of Sterilizing Effect of Nonequilibrium Atmospheric-Pressure He/O2 and Ar/O2 Plasma Jets

    Institute of Scientific and Technical Information of China (English)

    LI Shouzhe; LIM Jinpyo

    2008-01-01

    The sterilizing effect of the non-equilibrium atmospheric pressure plasma jet by applying it to the Bacillus subtilis spores is invesigated. A stable glow discharge in argon or helium gas fed with active gas (oxygen), was generated in the coaxial cylindrical reactor powered by the radio-frequency power supply at atmospheric pressure. The experimental results indicated that the efficiency of killingspores by making use of an Ar/O2 plasma jet was much better than with a He/O2 plasma jet. The decimal reduction value of Ar/O2 and He/O2 plasma jets under the same experimental conditions was 4.5 seconds and 125 seconds, respectively. It was found that there exists an optimum oxygen concentration for a certain input power, at which the sterilization efficiency reaches a maximum value. It is believed that the oxygen radicals are generated most efficiently under this optimum condition.

  11. An Alternative to Annealing TiO2 Nanotubes for Morphology Preservation: Atmospheric Pressure Plasma Jet Treatment.

    Science.gov (United States)

    Seo, Sang-Hee; Uhm, Soo-Hyuk; Kwon, Jae-Sung; Choi, Eun Ha; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2015-03-01

    Titanium oxide nanotube layer formed by plasma electrolytic oxidation (PEO) is known to be excellent in biomaterial applications. However, the annealing process which is commonly performed on the TiO2 nanotubes cause defects in the nanotubular structure. The purpose of this work was to apply a non-thermal atmospheric pressure plasma jet on diameter-controlled TiO2 nanotubes to mimic the effects of annealing while maintaining the tubular structure for use as biomaterial. Diameter-controlled nanotube samples fabricated by plasma electrolytic oxidation were dried and prepared under three different conditions: untreated, annealed at 450 °C for 1 h in air with a heating rate of 10 °C/min, and treated with an air-based non-thermal atmospheric pressure plasma jet for 5 minutes. The contact angle measurement was investigated to confirm the enhanced hydrophilicity of the TiO2 nanotubes. The chemical composition of the surface was studied using X-ray photoelectron spectroscopy, and the morphology of TiO2 nanotubes was examined by field emission scanning electron microscopy. For the viability of the cell, the attachment of the osteoblastic cell line MC3T3-E1 was determined using the water-soluble tetrazolium salt assay. We found that there are no morphological changes in the TiO2 nanotubular structure after the plasma treatment. Also, we investigated a change in the chemical composition and enhanced hydrophilicity which result in improved cell behavior. The results of this study indicated that the non-thermal atmospheric pressure plasma jet results in osteoblast functionality that is comparable to annealed samples while maintaining the tubular structure of the TiO2 nanotubes. Therefore, this study concluded that the use of a non-thermal atmospheric pressure plasma jet on nanotube surfaces may replace the annealing process following plasma electrolytic oxidation.

  12. Hybrid layers deposited by an atmospheric pressure plasma process for corrosion protection of galvanized steel.

    Science.gov (United States)

    Del Frari, D; Bour, J; Bardon, J; Buchheit, O; Arnoult, C; Ruch, D

    2010-04-01

    Finding alternative treatments to reproduce anticorrosion properties of chromated coatings is challenging since both physical barrier and self-healing effects are needed. Siloxane based treatments are known to be a promising way to achieve physical barrier coatings, mainly plasma polymerized hexamethyldisiloxane (ppHMDSO). In addition, it is known that cerium-based coatings can also provide corrosion protection of metals by means of self-healing effect. In this frame, innovative nanoAlCeO3/ppHMDSO layers have thus been deposited and studied. These combinations allow to afford a good physical barrier effect and active properties. Liquid siloxane and cerium-based particles mixture is atomized and introduced as precursors into a carrier gas. Gas mixture is then injected into an atmospheric pressure dielectric barrier discharge (DBD) where plasma polymerization of the siloxane precursor occurs. The influence of cerium concentration on the coating properties is investigated: coating structure and topography have been studied by scanning electron microscopy (SEM) and interferometry, and corrosion resistance of these different coatings is compared by electrochemistry techniques: polarization curves and electrochemical impedance spectroscopy (EIS). Potential self-healing property afforded by cerium in the layer was studied by associating EIS measurements and nanoscratch controlled damaging. Among the different combinations investigated, mixing of plasma polymerized HMDSO and AICeO3 nanoparticles seems to give promising results with a good physical barrier and interesting electroactive properties. Indeed, corrosion currents measured on such coatings are almost as low as those measured with the chromated film. Combination of nanoscratch damaging of layers with EIS experiments to investigate self-healing also allow to measure the active protection property of such layers.

  13. Cold atmospheric pressure plasma treatment of ready-to-eat meat: Inactivation of Listeria innocua and changes in product quality

    DEFF Research Database (Denmark)

    Rød, Sara Katrine; Hansen, Flemming; Leipold, Frank

    2012-01-01

    The application of cold atmospheric pressure plasma for decontamination of a sliced ready-to-eat (RTE) meat product (bresaola) inoculated with Listeria innocua was investigated. Inoculated samples were treated at 15.5, 31, and 62 W for 2–60 s inside sealed linear-low-density-polyethylene bags...

  14. Application of a Non-thermal Atmospheric Pressure Plasma Jet to the Decomposition of Salicylic Acid to Inorganic Carbon

    OpenAIRE

    Kuroda, Kosuke; Ishijima, Tatsuo; Kaga, Toshiki; Shiomomura, Kai; Ninomiya, Kazuaki; Takahashi, Kenji

    2015-01-01

    A non-thermal atmospheric pressure plasma jet technique was applied to decompose salicylic acid to inorganic carbon. Excess hydroxyl radical, which has a high oxidation potential, decomposed salicylic acid within 10 min, and total organic carbon decreased to 20% after 30 min. © 2015 The Chemical Society of Japan.

  15. Development of atmospheric pressure large area plasma jet for sterilisation and investigation of molecule and plasma interaction

    Science.gov (United States)

    Zerbe, Kristina; Iberler, Marcus; Jacoby, Joachim; Wagner, Christopher

    2016-09-01

    The intention of the project is the development and improvement of an atmospheric plasma jet based on various discharge forms (e.g. DBD, RF, micro-array) for sterilisation of biomedical equipment and investigation of biomolecules under the influence of plasma stress. The major objective is to design a plasma jet with a large area and an extended length. Due to the success on small scale plasma sterilisation the request of large area plasma has increased. Many applications of chemical disinfection in environmental and medical cleaning could thereby be complemented. Subsequently, the interaction between plasma and biomolecules should be investigated to improve plasma strerilisation. Special interest will be on non equilibrium plasma electrons affecting the chemical bindings of organic molecules.

  16. An experimental study on discharge characteristics in a pulsed-dc atmospheric pressure CH3OH/Ar plasma jet

    Science.gov (United States)

    Qian, Muyang; Liu, Sanqiu; Yang, Congying; Pei, Xuekai; Lu, Xinpei; Zhang, Jialiang; Wang, Dezhen

    2016-10-01

    Recently, C/H/Ar plasma discharges found enormous potential and possibility in carbonaceous compounds conversion and production. In this work, a pulsed-dc CH3OH/Ar plasma jet generated at atmospheric pressure is investigated by means of optical and electrical diagnosis concerning the variation of its basic parameters, absolute concentration of OH radicals, and plasma temperature with different CH3OH/Ar volume ratios, in the core region of discharge with needle-to-ring electrode configuration. The voltage-current characteristics are also measured at different CH3OH/Ar ratios. Laser-induced fluorescence (LIF) results here show that only small amounts of added methanol vapor to argon plasma (about 0.05% CH3OH/Ar volume ratio) is favorable for the production of OH radicals. The optical emission lines of CH, CN, and C2 radicals have been detected in the CH3OH/Ar plasma. And, the plasma temperatures increase with successive amount of added methanol vapor to the growth plasma. Moreover, qualitative discussions are presented regarding the mechanisms for methanol dissociation and effect of the CH3OH component on the Ar plasma discharge at atmospheric pressure.

  17. Laser schlieren deflectometry for temperature analysis of filamentary non-thermal atmospheric pressure plasma

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, J.; Foest, R.; Reuter, S.; Weltmann, K.-D. [INP Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Kewitz, T. [Institute of Experimental and Applied Physics, University Kiel, 24098 Kiel (Germany); Sperka, J. [Department of Physical Electronics, Masaryk University, 61137 Brno (Czech Republic)

    2012-10-15

    The heat convection generated by micro filaments of a self-organized non-thermal atmospheric pressure plasma jet in Ar is characterized by employing laser schlieren deflectometry (LSD). It is demonstrated as a proof of principle, that the spatial and temporal changes of the refractive index n in the optical beam path related to the neutral gas temperature of the plasma jet can be monitored and evaluated simultaneously. The refraction of a laser beam in a high gradient field of n(r) with cylindrical symmetry is given for a general real refraction index profile. However, the usually applied Abel approach represents an ill-posed problem and in particular for this plasma configuration. A simple analytical model is proposed in order to minimize the statistical error. Based on that, the temperature profile, specifically the absolute temperature in the filament core, the FWHM, and the frequencies of the collective filament dynamics are obtained for non-stationary conditions. For a gas temperature of 700 K inside the filament, the presented model predicts maximum deflection angles of the laser beam of 0.3 mrad which is in accordance to the experimental results obtained with LSD. Furthermore, the experimentally obtained FWHM of the temperature profile produced by the filament at the end of capillary is (1.5 {+-} 0.2) mm, which is about 10 times wider than the visual radius of the filament. The obtained maximum temperature in the effluent is (450 {+-} 30) K and is in consistence with results of other techniques. The study demonstrates that LSD represents a useful low-cost method for monitoring the spatiotemporal behaviour of microdischarges and allows to uncover their dynamic characteristics, e.g., the temperature profile even for challenging diagnostic conditions such as moving thin discharge filaments. The method is not restricted to the miniaturized and self-organized plasma studied here. Instead, it can be readily applied to other configurations that produce measurable

  18. Laser schlieren deflectometry for temperature analysis of filamentary non-thermal atmospheric pressure plasma

    Science.gov (United States)

    Schäfer, J.; Foest, R.; Reuter, S.; Kewitz, T.; Šperka, J.; Weltmann, K.-D.

    2012-10-01

    The heat convection generated by micro filaments of a self-organized non-thermal atmospheric pressure plasma jet in Ar is characterized by employing laser schlieren deflectometry (LSD). It is demonstrated as a proof of principle, that the spatial and temporal changes of the refractive index n in the optical beam path related to the neutral gas temperature of the plasma jet can be monitored and evaluated simultaneously. The refraction of a laser beam in a high gradient field of n(r) with cylindrical symmetry is given for a general real refraction index profile. However, the usually applied Abel approach represents an ill-posed problem and in particular for this plasma configuration. A simple analytical model is proposed in order to minimize the statistical error. Based on that, the temperature profile, specifically the absolute temperature in the filament core, the FWHM, and the frequencies of the collective filament dynamics are obtained for non-stationary conditions. For a gas temperature of 700 K inside the filament, the presented model predicts maximum deflection angles of the laser beam of 0.3 mrad which is in accordance to the experimental results obtained with LSD. Furthermore, the experimentally obtained FWHM of the temperature profile produced by the filament at the end of capillary is (1.5 ± 0.2) mm, which is about 10 times wider than the visual radius of the filament. The obtained maximum temperature in the effluent is (450 ± 30) K and is in consistence with results of other techniques. The study demonstrates that LSD represents a useful low-cost method for monitoring the spatiotemporal behaviour of microdischarges and allows to uncover their dynamic characteristics, e.g., the temperature profile even for challenging diagnostic conditions such as moving thin discharge filaments. The method is not restricted to the miniaturized and self-organized plasma studied here. Instead, it can be readily applied to other configurations that produce measurable

  19. Tailoring electron energy distribution functions through energy confinement in dual radio-frequency driven atmospheric pressure plasmas

    Energy Technology Data Exchange (ETDEWEB)

    O' Neill, C.; Waskoenig, J. [Centre for Plasma Physics, School of Maths and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Gans, T. [Centre for Plasma Physics, School of Maths and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom)

    2012-10-08

    A multi-scale numerical model based on hydrodynamic equations with semi-kinetic treatment of electrons is used to investigate the influence of dual frequency excitation on the effective electron energy distribution function (EEDF) in a radio-frequency driven atmospheric pressure plasma. It is found that variations of power density, voltage ratio, and phase relationship provide separate control over the electron density and the mean electron energy. This is exploited to directly influence both the phase dependent and time averaged effective EEDF. This enables tailoring the EEDF for enhanced control of non-equilibrium plasma chemical kinetics at ambient pressure and temperature.

  20. Roles of charged particles and reactive species on cell membrane permeabilization induced by atmospheric-pressure plasma irradiation

    Science.gov (United States)

    Sasaki, Shota; Kanzaki, Makoto; Hokari, Yutaro; Tominami, Kanako; Mokudai, Takayuki; Kanetaka, Hiroyasu; Kaneko, Toshiro

    2016-07-01

    As factors that influence cell membrane permeabilization during direct and indirect atmospheric-pressure plasma irradiation, charged particle influx, superoxide anion radicals (O2 -•), and hydrogen peroxide (H2O2) in plasma-irradiated solution were evaluated. These are the three strong candidate factors and might multiply contribute to cell membrane permeabilization. In particular, a shorter plasma diffusion distance leads to the enhancement of the direct effects such as charged particle influx and further increase cell membrane permeability. In addition, O2 -• dissipates over time (a life span of the order of minutes) in plasma-irradiated water, and the deactivation of a plasma-irradiated solution in term of cell membrane permeabilization occurs in a life span of the same order. These results could promote the understanding of the mechanism of plasma-induced cell membrane permeabilization.

  1. Influence of He/O 2 atmospheric pressure plasma jet treatment on subsequent wet desizing of polyacrylate on PET fabrics

    Science.gov (United States)

    Li, Xuming; Lin, Jun; Qiu, Yiping

    2012-01-01

    The influence of He/O2 atmospheric pressure plasma jet (APPJ) treatment on subsequent wet desizing of polyacrylate on PET fabrics was studied in the present paper. Weight loss results indicated that the weight loss increased with an increase of plasma treatment time. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) showed an increased surface roughness after the plasma treatment. SEM also showed that the fiber surfaces were as clean as unsized fibers after 35 s treatment followed by NaHCO3 desizing. X-ray photoelectron spectroscopy (XPS) analysis indicated that oxygen-based functional groups increased for the plasma treated polyacrylate sized fabrics. The percent desizing ratio (PDR) results showed that more than 99% PDR was achieved after 65 s plasma treatment followed by a 5 min NaHCO3 desizing. Compared to conventional wet desizing, indicating that plasma treatment could significantly reduce desizing time.

  2. Disinfection of ocular cells and tissues by atmospheric-pressure cold plasma.

    Directory of Open Access Journals (Sweden)

    Paola Brun

    Full Text Available BACKGROUND: Low temperature plasmas have been proposed in medicine as agents for tissue disinfection and have received increasing attention due to the frequency of bacterial resistance to antibiotics. This study explored whether atmospheric-pressure cold plasma (APCP generated by a new portable device that ionizes a flow of helium gas can inactivate ocular pathogens without causing significant tissue damage. METHODOLOGY/PRINCIPAL FINDINGS: We tested the APCP effects on cultured Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Candida albicans, Aspergillus fumigatus and Herpes simplex virus-1, ocular cells (conjunctival fibroblasts and keratocytes and ex-vivo corneas. Exposure to APCP for 0.5 to 5 minutes significantly reduced microbial viability (colony-forming units but not human cell viability (MTT assay, FACS and Tunel analysis or the number of HSV-1 plaque-forming units. Increased levels of intracellular reactive oxygen species (ROS in exposed microorganisms and cells were found using a FACS-activated 2',7'-dichlorofluorescein diacetate probe. Immunoassays demonstrated no induction of thymine dimers in cell cultures and corneal tissues. A transient increased expression of 8-OHdG, genes and proteins related to oxidative stress (OGG1, GPX, NFE2L2, was determined in ocular cells and corneas by HPLC, qRT-PCR and Western blot analysis. CONCLUSIONS: A short application of APCP appears to be an efficient and rapid ocular disinfectant for bacteria and fungi without significant damage on ocular cells and tissues, although the treatment of conjunctival fibroblasts and keratocytes caused a time-restricted generation of intracellular ROS and oxidative stress-related responses.

  3. Influence of voltage magnitude on the dynamic behavior of a stable helium atmospheric pressure plasma jet

    Science.gov (United States)

    Ning, Wenjun; Wang, Lijun; Wu, Chen; Jia, Shenli

    2014-08-01

    Effects of voltage magnitude on the development of a stable helium atmospheric pressure plasma jet are investigated by current measurements and high temporal-resolution streak images. Generated by a coaxial dielectric barrier discharge structure, the entire discharge can be classified into three regions: discharges in the tube gap, downstream jet, and up-streamer. The discharge morphologies of each region are analyzed. In the positive discharge phase, there are two discharges in the tube gap between the electrodes; the first one is ignited as corona and then developed into streamer corona, and the second one is similar with positive glow. The downstream jet is ignited independently from the discharge in the tube gap. Referred as "plasma bullet," the dynamic behavior of the jet can be well described as a positive streamer. Under specific applied voltage, the jet is found to be composed by double bullets in which case the jet length decreases since that less charge is carried by the first bullet. The up-streamer can be captured as long as the discharge in the tube gap is activated. Propagating with velocity of ˜4 km/s, the up-streamer can be regarded as the extension of the first discharge in the tube gap. In the negative discharge phase, the discharge is confined in the tube gap with nearly symmetrical morphology with the positive one. Besides, with the rising of voltage, the negative discharge is initially intensified and then turns weaker after surpassing certain voltage, which may provide suitable condition for the occurrence of double-bullet phenomenon.

  4. Atmospheric pressure plasma treatment of black peppercorns inoculated with Salmonella and held under controlled storage.

    Science.gov (United States)

    Sun, Shengqian; Anderson, Nathan M; Keller, Susanne

    2014-12-01

    Spices, including black pepper, are a source of microbial contamination and have been linked to outbreaks of salmonellosis when added to products that undergo no further processing. Traditional thermal processing employed to reduce microbial contamination can lead to losses of heat-sensitive compounds. Thus, alternative processes such as atmospheric pressure plasma (APP) are desirable. The purpose of this research was to determine the efficacy of APP in the destruction of Salmonella inoculated on the surface of peppercorns. Secondarily, we examined the effect of storage on the subsequent inactivation of Salmonella on the surfaces of black peppercorns by APP. Black peppercorns inoculated with a cocktail of Salmonella enterica serotypes Oranienburg, Tennessee, Anatum, and Enteritidis were stored at 25 °C, 33% relative humidity (RH); 25 °C, 97% RH; and, 37 °C, 33% RH for 10 d and additionally at 25 °C, 33% RH for 1 and 30 d then treated with APP. Results showed that Salmonella populations decreased significantly (P 0.05). Approximately a 4.5- to 5.5-log10 reduction in population was achieved after 60 to 80 s treatment. A combination of treatments, storage and 80 s of plasma, may achieve a total reduction on the order of 7-log10 CFU/g. These findings support the potential of APP to decontaminate Salmonella on the surfaces of black peppercorns and other dry foods and illustrate that a multiple hurdle approach may prove effective for achieving significant reductions of Salmonella in many low-moisture foods.

  5. Atmospheric-Pressure Cold Plasma Induces Transcriptional Changes in Ex Vivo Human Corneas.

    Directory of Open Access Journals (Sweden)

    Umberto Rosani

    Full Text Available Atmospheric pressure cold plasma (APCP might be considered a novel tool for tissue disinfection in medicine since the active chemical species produced by low plasma doses, generated by ionizing helium gas in air, induces reactive oxygen species (ROS that kill microorganisms without substantially affecting human cells.In this study, we evaluated morphological and functional changes in human corneas exposed for 2 minutes (min to APCP and tested if the antioxidant n-acetyl l-cysteine (NAC was able to inhibit or prevent damage and cell death.Immunohistochemistry and western blotting analyses of corneal tissues collected at 6 hours (h post-APCP treatment demonstrated no morphological tissue changes, but a transient increased expression of OGG1 glycosylase that returned to control levels in 24 h. Transcriptome sequencing and quantitative real time PCR performed on different corneas revealed in the treated corneas many differentially expressed genes: namely, 256 and 304 genes showing expression changes greater than ± 2 folds in the absence and presence of NAC, respectively. At 6 h post-treatment, the most over-expressed gene categories suggested an active or enhanced cell functioning, with only a minority of genes specifically concerning oxidative DNA damage and repair showing slight over-expression values (<2 folds. Moreover, time-related expression analysis of eight genes up-regulated in the APCP-treated corneas overall demonstrated the return to control expression levels after 24 h.These findings of transient oxidative stress accompanied by wide-range transcriptome adjustments support the further development of APCP as an ocular disinfectant.

  6. Particle Densities of the Atmospheric-Pressure Argon Plasmas Generated by the Pulsed Dielectric Barrier Discharges

    Science.gov (United States)

    Pan, Jie; Li, Li; Wang, Yunuan; Xiu, Xianwu; Wang, Chao; Song, Yuzhi

    2016-11-01

    Atmospheric-pressure argon plasmas have received increasing attention due to their high potential in many industrial and biomedical applications. In this paper, a 1-D fluid model is used for studying the particle density characteristics of the argon plasmas generated by the pulsed dielectric barrier discharges. The temporal evolutions of the axial particle density distributions are illustrated, and the influences of changing the main discharge conditions on the averaged particle densities are researched by independently varying the various discharge conditions. The calculation results show that the electron density and the ion density reach two peaks near the momentary cathodes during the rising and the falling edges of the pulsed voltage. Compared with the charged particle densities, the densities of the resonance state atom Arr and the metastable state atom Arm have more uniform axial distributions, reach higher maximums and decay more slowly. During the platform of the pulsed voltage and the time interval between the pulses, the densities of the excited state atom Ar* are far lower than those of the Arr or the Arm. The averaged particle densities of the different considered particles increase with the increases of the amplitude and the frequency of the pulsed voltage. Narrowing the discharge gap and increasing the relative dielectric constant of the dielectric also contribute to the increase of the averaged particle densities. The effects of reducing the discharge gap distance on the neutral particle densities are more significant than the influences on the charged particle densities. supported by Natural Science Foundation of Shandong Province, China (No. ZR2015AQ008), and Project of Shandong Province Higher Educational Science and Technology Program of China (No. J15LJ04)

  7. Development of atmospheric pressure plasma processing machine tool for large aperture optics

    Science.gov (United States)

    Su, Xing; Wu, Yangong; Zhang, Peng; Xin, Qiang; Wang, Bo

    2016-10-01

    In recent years, major projects, such as National Ignition Facility and Laser Mégajoule, have generated great demands for large aperture optics with high surface accuracy and low Subsurface Damage (SSD) at the mean time. In order to remove SSD and improve surface quality, optics is fabricated by sub-aperture polishing. However, the efficiency of the sub-aperture polishing has been a bottleneck step for the optics manufacturing. Atmospheric Pressure Plasma Processing (APPP) as an alternate method offers high potential for speeding up the polishing process. This technique is based on chemical etching, hence there is no physical contact and no damage is induced. In this paper, a fast polishing machine tool is presented which is designed for fast polishing of the large aperture optics using APPP. This machine tool employs 3PRS-XY hybrid structure as its framework. There is a platform in the 3PRS parallel module to support the plasma generating system. And the large work piece is placed on the XY stage. In order to realize the complex motion trajectory for polishing the freeform optics, five axis of the tool operate simultaneously. To overcome the complexity of inverse kinematics calculation, a dedicated motion control system is also designed for speeding up the motion response. For high removal rate, the individual influence of several key processing parameters is investigated. And under specific production condition, this machine tool offers a high material over 30mm3/min for fused silica substrates. This results shows that APPP machine tool has a strong potential for fast polishing large optics without introducing SSD.

  8. Inhibitory effect of silver nanoparticles mediated by atmospheric pressure air cold plasma jet against dermatophyte fungi.

    Science.gov (United States)

    Ouf, Salama A; El-Adly, Amira A; Mohamed, Abdel-Aleam H

    2015-10-01

    In an in vitro study with five clinical isolates of dermatophytes, the MIC(50) and MIC(100) values of silver nanoparticles (AgNPs) ranged from 5 to 16 and from 15 to 32 μg ml(- 1), respectively. The combined treatment of AgNPs with atmospheric pressure-air cold plasma (APACP) induced a drop in the MIC(50) and MIC100 values of AgNPs reaching 3-11 and 12-23 μg ml(- 1), respectively, according to the examined species. Epidermophyton floccosum was the most sensitive fungus to AgNPs, while Trichophyton rubrum was the most tolerant. AgNPs induced significant reduction in keratinase activity and an increase in the mycelium permeability that was greater when applied combined with plasma treatment. Scanning electron microscopy showed electroporation of the cell walls and the accumulation of AgNPs on the cell wall and inside the cells, particularly when AgNPs were combined with APACP treatment. An in vivo experiment with dermatophyte-inoculated guinea pigs indicated that the application of AgNPs combined with APACP was more efficacious in healing and suppressing disease symptoms of skin as compared with the application of AgNPs alone. The recovery from the infection reached 91.7 % in the case of Microsporum canis-inoculated guinea pigs treated with 13 μg ml(- 1) AgNPs combined with APACP treatment delivered for 2  min. The emission spectra indicated that the efficacy of APACP was mainly due to generation of NO radicals and excited nitrogen molecules. These reactive species interact and block the activity of the fungal spores in vitro and in the skin lesions of the guinea pigs. The results achieved are promising compared with fluconazole as reference antifungal drug.

  9. Cleaning of carbon materials from flat surfaces and castellation gaps by an atmospheric pressure plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Stancu, C. [National Institute for Laser, Plasma and Radiation Physics, Atomistilor Str. 409, PO Box Mg36, Magurele-Bucharest, 077125 (Romania); Alegre, D. [Laboratorio Nacional de Fusión, As. Euratom/Ciemat, Avda. Complutense 22, 28040, Madrid (Spain); Ionita, E.R.; Mitu, B. [National Institute for Laser, Plasma and Radiation Physics, Atomistilor Str. 409, PO Box Mg36, Magurele-Bucharest, 077125 (Romania); Grisolia, C. [CEA, IRFM, F-13108, Saint-Paul-lez-Durance (France); Tabares, F.L. [Laboratorio Nacional de Fusión, As. Euratom/Ciemat, Avda. Complutense 22, 28040, Madrid (Spain); Dinescu, G., E-mail: dinescug@infim.ro [National Institute for Laser, Plasma and Radiation Physics, Atomistilor Str. 409, PO Box Mg36, Magurele-Bucharest, 077125 (Romania)

    2016-02-15

    Highlights: • Atmospheric plasma jets operated with nitrogen, oxygen and their mixtures are used for cleaning surfaces of carbon residues • Efficient plasma jet cleaning of carbon deposits from flat surfaces and inside gaps of castellated surfaces is demonstrated • Plasma jet cleaning is more effective at the gaps entrance and on their bottom - Abstract: A study of the removal of carbon layers from flat and castellated surfaces by a plasma jet source operated in open atmosphere is presented. Amorphous hydrogenated carbon films deposited on silicon substrates, on aluminium made castellated surfaces, and graphitic carbon plates were used. The erosion effects of plasmas generated either in pure argon, nitrogen or in their mixtures with hydrogen, ammonia, oxygen are compared. Highest erosion was obtained with nitrogen and nitrogen/oxygen plasmas. Plasmas in argon and containing hydrogen, and ammonia have shown a low erosion rate. A large removal rate by pure nitrogen plasma jet of 3.2 mg/min was found by scanning graphitic carbon flat surfaces for optimum process parameters. Adding small quantities of oxygen led to a removal rate enhancement by a factor of 3. Finally, the integral removal rate of amorphous hydrogenated carbon deposited in gaps 23 mm deep and 0.5 mm wide was of the order of 0.35 mg/min. The layer elimination was more efficient at the top and at the bottom of the gaps, precisely where the thickest codeposits develop in a nuclear fusion device.

  10. High throughput atmospheric pressure plasma-induced graft polymerization for identifying protein-resistant surfaces.

    Science.gov (United States)

    Gu, Minghao; Kilduff, James E; Belfort, Georges

    2012-02-01

    Three critical aspects of searching for and understanding how to find highly resistant surfaces to protein adhesion are addressed here with specific application to synthetic membrane filtration. They include the (i) discovery of a series of previously unreported monomers from a large library of monomers with high protein resistance and subsequent low fouling characteristics for membrane ultrafiltration of protein-containing fluids, (ii) development of a new approach to investigate protein-resistant mechanisms from structure-property relationships, and (iii) adaptation of a new surface modification method, called atmospheric pressure plasma-induced graft polymerization (APP), together with a high throughput platform (HTP), for low cost vacuum-free synthesis of anti-fouling membranes. Several new high-performing chemistries comprising two polyethylene glycol (PEG), two amines and one zwitterionic monomers were identified from a library (44 commercial monomers) of five different classes of monomers as strong protein-resistant monomers. Combining our analysis here, using the Hansen solubility parameters (HSP) approach, and data from the literature, we conclude that strong interactions with water (hydrogen bonding) and surface flexibility are necessary for producing the highest protein resistance. Superior protein-resistant surfaces and subsequent anti-fouling performance was obtained with the HTP-APP as compared with our earlier HTP-photo graft-induced polymerization (PGP).

  11. Fluorescence microscopic analysis of antifungal effects of cold atmospheric pressure plasma in Saccharomyces cerevisiae.

    Science.gov (United States)

    Itooka, Koki; Takahashi, Kazuo; Izawa, Shingo

    2016-11-01

    Cold atmospheric pressure plasma (CAP) has potential to be utilized as an alternative method for sterilization in food industries without thermal damage or toxic residues. In contrast to the bactericidal effects of CAP, information regarding the efficacy of CAP against eukaryotic microorganisms is very limited. Therefore, herein we investigated the effects of CAP on the budding yeast Saccharomyces cerevisiae, with a focus on the cellular response to CAP. The CAP treatment caused oxidative stress responses including the nuclear accumulation of the oxidative stress responsive transcription factor Yap1, mitochondrial fragmentation, and enhanced intracellular oxidation. Yeast cells also induced the expression of heat shock protein (HSP) genes and formation of Hsp104 aggregates when treated with CAP, suggesting that CAP denatures proteins. As phenomena unique to eukaryotic cells, the formation of cytoplasmic mRNP granules such as processing bodies and stress granules and changes in the intracellular localization of Ire1 were caused by the treatment with CAP, indicating that translational repression and endoplasmic reticulum (ER) stress were induced by the CAP treatment. These results suggest that the fungicidal effects of CAP are attributed to the multiple severe stresses.

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

    Science.gov (United States)

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

    2015-09-01

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

  13. Chain Assemblies from Nanoparticles Synthesized by Atmospheric Pressure Plasma Enhanced Chemical Vapor Deposition: The Computational View.

    Science.gov (United States)

    Mishin, Maxim V; Zamotin, Kirill Y; Protopopova, Vera S; Alexandrov, Sergey E

    2015-12-01

    This article refers to the computational study of nanoparticle self-organization on the solid-state substrate surface with consideration of the experimental results, when nanoparticles were synthesised during atmospheric pressure plasma enhanced chemical vapor deposition (AP-PECVD). The experimental study of silicon dioxide nanoparticle synthesis by AP-PECVD demonstrated that all deposit volume consists of tangled chains of nanoparticles. In certain cases, micron-sized fractals are formed from tangled chains due to deposit rearrangement. This work is focused on the study of tangled chain formation only. In order to reveal their formation mechanism, a physico-mathematical model was developed. The suggested model was based on the motion equation solution for charged and neutral nanoparticles in the potential fields with the use of the empirical interaction potentials. In addition, the computational simulation was carried out based on the suggested model. As a result, the influence of such experimental parameters as deposition duration, particle charge, gas flow velocity, and angle of gas flow was found. It was demonstrated that electrical charges carried by nanoparticles from the discharge area are not responsible for the formation of tangled chains from nanoparticles, whereas nanoparticle kinetic energy plays a crucial role in deposit morphology and density. The computational results were consistent with experimental results.

  14. On the Role of Metastable Argon in Cold Atmospheric Pressure Plasma Jets with Shielding Gas Device

    Science.gov (United States)

    Schmidt-Bleker, Ansgar; Winter, Jorn; Sousa, Joao Santos; Puech, Vincent; Weltmann, Klaus-Dieter; Reuter, Stephan; ZIK plasmatis at the INP Greifswald e. V. Team; Laboratoire de Physique des Gaz et des Plasmas (LPGP), CNRS; Université Paris-Sud Team

    2014-10-01

    Shielding gas devices are a valuable tool for controlling the reactive species output of Cold Atmospheric Pressure Plasma (CAPP) Jets for biomedical applications. In this work we investigate the effect of different shielding gas compositions using a CAPP jet (kinpen) operated with argon. As shielding gas various mixtures of N2 and O2 are used. Metastable argon (Ar*) has been quantified using laser absorption spectroscopy and was identified as an important energy carrier in the CAPP jets effluent. The Ar* excitation dynamics was studied using phase resolve optical emission spectroscopy. Based on these findings a kinetic model for the gas phase chemistry has been developed that uses the Ar* density and dynamics as input and yields densities of O3, NO2, HNO2, HNO3, N2O5, H2O2 and N2O produced by the CAPP jet for different shielding gas compositions. The results are in good agreement with Fourier-Transform Infrared Spectroscopy measurements on these species. Authors gratefully acknowledge the funding by German Federal Ministry of Education a Research (BMBF) (Grant # 03Z2DN12).

  15. Reactive species in humidity containing atmospheric pressure plasma jets - Numerical and experimental investigations

    Science.gov (United States)

    Schroeter, Sandra; Bredin, J.; Wijaikhum, A.; West, A.; Dedrick, J.; Niemi, K.; Gibson, A. R.; Foucher, M.; Booth, J.-P.; de Oliveira, N.; Joyeux, D.; Nahon, L.; Gorbanev, Y.; Chechik, V.; Wagenaars, E.; Gans, T.; O'Connell, D.

    2016-09-01

    The formation and absolute densities of oxygen and hydrogen containing reactive species such as atomic oxygen (O), hydrogen (H), hydroxyl radicals (OH) and hydrogen peroxide (H2O2) in an atmospheric pressure plasma jet (APPJ) are investigated as a function of the humidity content in the helium feed gas. APPJs are effective sources for these species, which are known to be biologically active and form a central role in their potential for biomedical applications. To develop and tailor APPJs for therapeutics, quantification of the reactive species produced is necessary. In this work, different diagnostic techniques, such as UV and VUV absorption spectroscopy and picosecond two-photon absorption laser-induced fluorescence (ps-TALIF) and a 0-dimensional chemical kinetics model are applied. We find that the densities of hydrogen containing species increase non-linearly with increasing feed gas humidity. The trend of atomic oxygen depends strongly on impurities present in the APPJ. The model results show that the dominant formation and destruction mechanisms of the species of interest are strongly influenced by the humidity content with different processes dominating at high and low humidity. Supported by UK EPSRC (EP/K018388/1, EP/H003797/1), the York-Paris CIRC and LABEX Plas@par (ANR11-IDEX-0004-02).

  16. A tomographic visualization of electric discharge sound fields in atmospheric pressure plasma using laser diffraction

    Science.gov (United States)

    Nakamiya, Toshiyuki; Mitsugi, Fumiaki; Iwasaki, Yoichiro; Ikegami, Tomoaki; Tsuda, Ryoichi; Sonoda, Yoshito; Danuta Stryczewska, Henryka

    2013-02-01

    The phase modulation of transparent gas can be detected using Fraunhofer diffraction technique, which we call optical wave microphone (OWM). The OWM is suitable for the detection of sonic wave from audible sound to ultrasonic wave. Because this technique has no influence on sound field or electric field during the measurement, we have applied it to the sound detection for the electric discharges. There is almost no research paper that uses the discharge sound to examine the electrical discharge phenomenon. Two-dimensional visualization of the sound field using the OWM is also possible when the computerized tomography (CT) is combined. In this work, coplanar dielectric barrier discharge sin different gases of Ar, N2, He were characterized via the OWM as well as applied voltage and discharge current. This is the first report to investigate the influence of the type of the atmospheric gas on the two-dimensional sound field distribution for the coplanar dielectric barrier discharge using the OWM with CT. Contribution to the Topical Issue "13th International Symposium on High Pressure Low Temperature Plasma Chemistry (Hakone XIII)", Edited by Nicolas Gherardi, Henryca Danuta Stryczewska and Yvan Ségui.

  17. Improvement of stability of sinusoidally driven atmospheric pressure plasma jet using auxiliary bias voltage

    Directory of Open Access Journals (Sweden)

    Hyun-Jin Kim

    2015-12-01

    Full Text Available In this study, we have proposed the auxiliary bias pulse scheme to improve the stability of atmospheric pressure plasma jets driven by an AC sinusoidal waveform excitation source. The stability of discharges can be significantly improved by the compensation of irregular variation in memory voltage due to the effect of auxiliary bias pulse. From the parametric study, such as the width, voltage, and onset time of auxiliary bias pulse, it has been demonstrated that the auxiliary bias pulse plays a significant role in suppressing the irregular discharges caused by the irregular variation in memory voltage and stable discharge can be initiated with the termination of the auxiliary bias pulse. As a result of further investigating the effects of the auxiliary pulse scheme on the jet stability under various process conditions such as the distance between the jet head and the counter electrode, and carrier gas flow, the jet stability can be improved by adjusting the amplitude and number of the bias pulse depending on the variations in the process conditions.

  18. Effect of atmospheric pressure plasma jet on the foodborne pathogens attached to commercial food containers.

    Science.gov (United States)

    Kim, Hyun-Joo; Jayasena, Dinesh D; Yong, Hae In; Alahakoon, Amali U; Park, Sanghoo; Park, Jooyoung; Choe, Wonho; Jo, Cheorun

    2015-12-01

    Bacterial biofilms are associated with numerous infections and problems in the health care and food industries. The aim of this study was to evaluate the bactericidal effect of an atmospheric pressure plasma (APP) jet on Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium biofilm formation on collagen casing (CC), polypropylene (PP) and polyethylene terephthalate (PET), which are widely used food container materials. The samples were treated separately with the APP jet at a 50-W input power for 5 and 10 min, and nitrogen (6 l per minute) gas combined with oxygen (10 standard cubic centimeters per minute) was used to produce the APP. The APP jet reduced the number of bacterial cells in a time-dependent manner. All pathogens attached to CC, PP, and PET were reduced by 3-4 log CFU/cm(2) by the 10-min APP treatment. The developed APP jet was effectively reduced biofilms on CC, PP, and PET.

  19. Simultaneous and long-lasting hydrophilization of inner and outer wall surfaces of polytetrafluoroethylene tubes by transferring atmospheric pressure plasmas

    Science.gov (United States)

    Chen, Faze; Song, Jinlong; Huang, Shuai; Xu, Sihao; Xia, Guangqing; Yang, Dezheng; Xu, Wenji; Sun, Jing; Liu, Xin

    2016-09-01

    Plasma hydrophilization is a general method to increase the surface free energy of materials. However, only a few works about plasma modification focus on the hydrophilization of tube inner and outer walls. In this paper, we realize simultaneous and long-lasting plasma hydrophilization on the inner and outer walls of polytetrafluoroethylene (PTFE) tubes by atmospheric pressure plasmas (APPs). Specifically, an Ar atmospheric pressure plasma jet (APPJ) is used to modify the PTFE tube’s outer wall and meanwhile to induce transferred He APP inside the PTFE tube to modify its inner wall surface. The optical emission spectrum (OES) shows that the plasmas contain many chemically active species, which are known as enablers for various applications. Water contact angle (WCA) measurements, x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) are used to characterize the plasma hydrophilization. Results demonstrate that the wettability of the tube walls are well improved due to the replacement of the surface fluorine by oxygen and the change of surface roughness. The obtained hydrophilicity decreases slowly during more than 180 d aging, indicating a long-lasting hydrophilization. The results presented here clearly demonstrate the great potential of transferring APPs for surface modification of the tube’s inner and outer walls simultaneously.

  20. Suprathermal electron energy spectrum and nonlocally affected plasma-wall interaction in helium/air micro-plasma at atmospheric pressure

    Science.gov (United States)

    Demidov, V. I.; Adams, S. F.; Miles, J. A.; Koepke, M. E.; Kurlyandskaya, I. P.

    2016-10-01

    Details of ground-state and excited-state neutral atoms and molecules in an atmospheric-pressure micro-discharge plasma may be obtained by plasma electron spectroscopy (PLES), based on a wall probe. The presence and transport of energetic (suprathermal) electrons, having a nonlocal origin, are responsible for electrostatic charging of the plasma boundary surfaces to potentials many times that associated with the ambient electron kinetic energy. The energy-flux distribution function is shown to be controllable for applications involving analysis of composition and processes taking place in a multiphase (plasma-gas-solid), chemically reactive, interaction region.

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

    Energy Technology Data Exchange (ETDEWEB)

    Uwe Kortshagen; Joachim Heberlein; Steven L. Girshick

    2009-06-01

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

  2. Non-thermal atmospheric pressure HF plasma source: generation of nitric oxide and ozone for bio-medical applications

    Science.gov (United States)

    Kühn, S.; Bibinov, N.; Gesche, R.; Awakowicz, P.

    2010-01-01

    A new miniature high-frequency (HF) plasma source intended for bio-medical applications is studied using nitrogen/oxygen mixture at atmospheric pressure. This plasma source can be used as an element of a plasma source array for applications in dermatology and surgery. Nitric oxide and ozone which are produced in this plasma source are well-known agents for proliferation of the cells, inhalation therapy for newborn infants, disinfection of wounds and blood ozonation. Using optical emission spectroscopy, microphotography and numerical simulation, the gas temperature in the active plasma region and plasma parameters (electron density and electron distribution function) are determined for varied nitrogen/oxygen flows. The influence of the gas flows on the plasma conditions is studied. Ozone and nitric oxide concentrations in the effluent of the plasma source are measured using absorption spectroscopy and electro-chemical NO-detector at variable gas flows. Correlations between plasma parameters and concentrations of the particles in the effluent of the plasma source are discussed. By varying the gas flows, the HF plasma source can be optimized for nitric oxide or ozone production. Maximum concentrations of 2750 ppm and 400 ppm of NO and O3, correspondingly, are generated.

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

    Directory of Open Access Journals (Sweden)

    Young-Hyo Ryu

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

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

    Science.gov (United States)

    Ryu, Young-Hyo; Kim, Yong-Hee; Lee, Jin-Young; Shim, Gun-Bo; Uhm, Han-Sup; Park, Gyungsoon; Choi, Eun Ha

    2013-01-01

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

  5. Membrane damage and active but nonculturable state in liquid cultures of Escherichia coli treated with an atmospheric pressure plasma jet.

    Science.gov (United States)

    Dolezalova, Eva; Lukes, Petr

    2015-06-01

    Electrical discharge plasmas can efficiently inactivate various microorganisms. Inactivation mechanisms caused by plasma, however, are not fully understood because of the complexity of both the plasma and biological systems. We investigated plasma-induced inactivation of Escherichia coli in water and mechanisms by which plasma affects bacterial cell membrane integrity. Atmospheric pressure argon plasma jet generated at ambient air in direct contact with bacterial suspension was used as a plasma source. We determined significantly lower counts of E. coli after treatment by plasma when they were assayed using a conventional cultivation technique than using a fluorescence-based LIVE/DEAD staining method, which indicated that bacteria may have entered the viable-but-nonculturable state (VBNC). We did not achieve resuscitation of these non-culturable cells, however, we detected their metabolic activity through the analysis of cellular mRNA, which suggests that cells may have been rather in the active-but-nonculturable state (ABNC). We hypothesize that peroxidation of cell membrane lipids by the reactive species produced by plasma was an important pathway of bacterial inactivation. Amount of malondialdehyde and membrane permeability of E. coli to propidium iodide increased with increasing bacterial inactivation by plasma. Membrane damage was also demonstrated by detection of free DNA in plasma-treated water.

  6. Preparation of nitrogen doped silicon oxides thin films by plasma polymerization of 3-aminopropyltriethoxylsilane using atmospheric pressure plasma jet

    Science.gov (United States)

    Lin, Yu-Chun; Wang, Meng-Jiy

    2016-01-01

    Surface modification techniques have been applied in various applications including self-cleaning surface, antibacterial filter, and biomaterials. In this study we employed the atmospheric pressure plasma jet (APPJ) deposition, a dry process for surface modification, to deposit 3-aminopropyltriethoxylsilane (APTES) on stainless steel (SS) on the purposes of simultaneously incorporating SiOx and nitrogen containing functionalities for the modulation of biofunctionality. The APPJ deposition allowed to form a thin layer of APTES with linear growth rate by controlling the deposition time. In addition, the surface chemical and physical properties, such as surface chemical composition, wettability, film thickness, and interactions with mammalian cells were evaluated by using different analytical methods. The results showed that the surface wettability was improved significantly due to the APTES deposition along with the increase of the incorporated nitrogen content. Moreover, the viability of L-929 fibroblasts was clearly promoted on the APTES deposited SS, which is most probably due to the thicker deposited films and higher density of nitrogen-containing functional groups. The outcomes of this research showed great potential to apply on metallic substrates in real time for biomedical related applications.

  7. Experimental investigation of a non-thermal atmospheric pressure plasma jet

    Science.gov (United States)

    Begum, Asma

    The main objective of this dissertation is to understand the formation of the plasma jet from the plasma pencil, and the propagation of the plasma jet in the ambient atmosphere where the effect of the external electric field is almost zero. Before investigating the formation and propagation phenomenon of the plasma jet, common physical properties of plasma jets are determined by using the imaging technique and optical emission spectroscopy. The first goal of this dissertation is to establish the laminar helium gas flow channel through a plasma pencil. The formation position, formation time, and the criterion of the plasma jet formation from the discharge chamber of a plasma pencil are investigated by imaging technique, optical emission spectroscopy, and electrical measurement technique. It shows that the plasma jet forms at the surface of the grounded dielectric as a positive plasma front. The formation time of the plasma jet decreases with applied voltage. The maximum power, total power, and average energy to the system and to the discharge are calculated from the total current, discharge current, input potential, and gap potential of the plasma pencil. The calculated average input power with applied voltage to the discharge shows that 56% of the input power is used in the discharge. The total charge in the discharge chamber is calculated by integrating the discharge current waveform. The critical charge in the discharge chamber required to generate a plasma jet is also determined. The propagation phenomenon of the plasma bullet in the ambient atmosphere has been investigated from the velocity curves of the plasma bullet along the jet axis for different applied voltages, pulse widths, and feed gas flow rates. The plasma bullet's velocity is measured by using two different techniques: (i) imaging technique and (ii) electrical technique. In imaging technique, ultra-fast ICCD images of the plasma jet have been taken at different times and positions, and from the

  8. Effect of additive oxygen gas on cellular response of lung cancer cells induced by atmospheric pressure helium plasma jet.

    Science.gov (United States)

    Joh, Hea Min; Choi, Ji Ye; Kim, Sun Ja; Chung, T H; Kang, Tae-Hong

    2014-10-16

    The atmospheric pressure helium plasma jet driven by pulsed dc voltage was utilized to treat human lung cancer cells in vitro. The properties of plasma plume were adjusted by the injection type and flow rate of additive oxygen gas in atmospheric pressure helium plasma jet. The plasma characteristics such as plume length, electric current and optical emission spectra (OES) were measured at different flow rates of additive oxygen to helium. The plasma plume length and total current decreased with an increase in the additive oxygen flow rate. The electron excitation temperature estimated by the Boltzmann plot from several excited helium emission lines increased slightly with the additive oxygen flow. The oxygen atom density in the gas phase estimated by actinometry utilizing argon was observed to increase with the additive oxygen flow. The concentration of intracellular reactive oxygen species (ROS) measured by fluorescence assay was found to be not exactly proportional to that of extracellular ROS (measured by OES), but both correlated considerably. It was also observed that the expression levels of p53 and the phospho-p53 were enhanced in the presence of additive oxygen flow compared with those from the pure helium plasma treatment.

  9. Effects of non-thermal atmospheric pressure pulsed plasma on the adhesion and durability of resin composite to dentin.

    Science.gov (United States)

    Han, Geum-Jun; Kim, Jae-Hoon; Chung, Sung-No; Chun, Bae-Hyeock; Kim, Chang-Keun; Seo, Deog-Gyu; Son, Ho-Hyun; Cho, Byeong-Hoon

    2014-12-01

    This study investigated the effect of low-power, non-thermal atmospheric pressure plasma (NT-APP) treatments, in pulsed and conventional modes, on the adhesion of resin composite to dentin and on the durability of the bond between resin composite and dentin. A pencil-type NT-APP jet was applied in pulsed and conventional modes to acid-etched dentin. The microtensile bond strength (MTBS) of resin composite to dentin was evaluated at 24 h and after thermocycling in one control group (no plasma) and in two experimental groups (pulsed plasma and conventional plasma groups) using the Scotchbond Multi-Purpose Plus Adhesive System. Data were analyzed using two-factor repeated-measures anova and Weibull statistics. Fractured surfaces and the bonded interfaces were evaluated using a field-emission scanning electron microscope. Although there were no significant differences between the plasma treatment groups, the plasma treatment improved the MTBS compared with the control group. After thermocycling, the MTBS did not decrease in the control or conventional plasma group but increased in the pulsed plasma group. Thermocycling increased the Weibull moduli of plasma-treated groups. In conclusion, plasma treatment using NT-APP improved the adhesion of resin composite to dentin. Using a pulsed energy source, the energy delivered to the dentin was effectively reduced without any reduction in bond strength or durability.

  10. Study of atmospheric pressure weakly ionized plasma as surface compatibilization technique for improved plastic composites loaded with cellulose based fillers

    Science.gov (United States)

    Lekobou, William Pimakouon

    Atmospheric pressure plasmas have gained considerable interest from researchers recently for their unique prospective of engineering surfaces with plasma without the need of vacuum systems. They offer the advantage of low energy consumption, minimal capital cost and their simplicity as compared to conventional low pressure plasmas make them easy to upscale from laboratory to industry size. The present dissertation summarizes results of our attempt at applying atmospheric pressure weakly ionized plasma (APWIP) to the engineering of plastic composites filled with cellulose based substrates. An APWIP reactor was designed and built based on a multipoint-to-grounded ring and screen configurations. The carrier gas was argon and acetylene serves as the precursor molecule. The APWIP reactors showed capability of depositing plasma polymerized coating rich in carbon on substrates positioned within the electrode gap as well as downstream of the plasma discharge into the afterglow region. Our findings show that films grow by forming islands which for prolonged deposition time grow into thin films showing nodules, aggregates of nodules and microspheres. They also show chemical structure similar to films deposited from hydrocarbons with other conventional plasma techniques. The plasma polymerized deposits were used on substrates to modify their surface properties. Results show the surface of wood veneer and wood flour can be finely tuned from hydrophilic to hydrophobic. It was achieved by altering the topography of the surfaces along with their chemical composition. The wettability of wood veneer was investigated with contact angle measurements on capacitive drops and the capillary effect was utilized to assess surface properties of wood flour exposed to the discharges.

  11. Heat Flux Characterization of DC Laminar-plasma Jets Impinging on a Flat Plate at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    孟显; 潘文霞; 张文宏; 吴承康

    2001-01-01

    By using steady and transient methods, the total heat fluxes and the distributions of the heat flux were measured experimentally for an argon DC laminar plasma jet impinging normally on a flat plate at atmospheric pressure. Results show that the total heat fluxes measured with a steady method are a little bit higher than those with a transient method. Numerical simulation work was executed to compare with the experimental results.

  12. Atmospheric pressure plasma treatment of glass fibre composite for adhesion improvement

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Mortensen, H.; Stenum, Bjarne

    2007-01-01

    Glass-fibre-reinforced polyester composite plates were treated with an atmospheric pressure dielectric barrier discharge. Synthetic air was used as the treatment gas. The water contact angle dropped markedly from 84 to 22° after a 2-s treatment, and decreased to 0° when the composite plates were...

  13. Bacterial-killing effect of atmospheric pressure non-equilibrium plasma jet and oral mucosa response.

    Science.gov (United States)

    Liu, Dexi; Xiong, Zilan; Du, Tianfeng; Zhou, Xincai; Cao, Yingguang; Lu, Xinpei

    2011-12-01

    Recently, plasma sterilization has attracted increasing attention in dental community for the atmospheric pressure non-equilibrium plasma jet (APNPs), which is driven by a kilohertz pulsed DC power, may be applied to the dental and oral diseases. However, it is still in doubt whether APNPs can effectively kill pathogenic bacteria in the oral cavity and produce no harmful effects on normal oral tissues, especially on normal mucosa. The aim of this study was to evaluate the bacterial-killing effect of APNPs in the biofilms containing a single breed of bacteria (Porphyromonas gingivalis, P.g.), and the pathological changes of the oral mucosa after treatment by APNPs. P.g. was incubated to form the biofilms in vitro, and the samples were divided into three groups randomly: group A (blank control); group B in which the biofilms were treated by APNPs (the setting of the equipment: 10 kHz, 1600 ns and 8 kV); group C in which the biofilms were exposed only to a gas jet without ignition of the plasma. Each group had three samples and each sample was processed for up to 5 min. The biofilms were then fluorescently stained, observed and photographed under a laser scanning confocal microscope. In the animal experiment, six male Japanese white rabbits were divided into two groups randomly (n=3 in each group) in terms of the different post-treatment time (1-day group and 5-day group). The buccal mucosa of the left side and the mucosa of the ventral surface of the tongue were treated by APNPs for 10 min in the same way as the bacterial biofilm experiment in each rabbit, and the corresponding mucosa of the other sides served as normal control. The clinical manifestations of the oral mucosa were observed and recorded every day. The rabbits were sacrificed one or five day(s) after APNPs treatment. The oral mucosa were harvested and prepared to haematoxylin and eosin-stained sections. Clinical observation and histopathological scores were used to assess mucosal changes. The results

  14. Improvement of Strength Characteristics of Aerospace Fiber Reinforced Composite Materials using Atmospheric Pressure Plasma-Graft Polymerization Treatment

    Science.gov (United States)

    Aoi, Tatsuji; Kuroki, Tomoyuki; Tahara, Mitsuru; Okubo, Masaaki

    The atmospheric pressure nonthermal plasma-graft polymerization treatment is applied for the surface modification of the organic fibers in order to enhance the strength of the aerospace structural composite material consisting of the laminated textiles. The influence of the treatment on the composite materials' strength properties is examined. As a result, the plasma-graft polymerization surface treatment is effective for the compression and bend of the composite materials. Because the interfacial bonding between each fiber and matrix resin is strengthened by the treatment, the strengths of the composite materials are increased.

  15. Numerical study of secondary electron emission in a coaxial radio-frequency driven plasma jet at atmospheric pressure

    CERN Document Server

    Hemke, Torben; Wollny, Alexander; Brinkmann, Ralf Peter; Mussenbrock, Thomas

    2011-01-01

    In this work we investigate a numerical model of a coaxial RF-driven plasma jet operated at atmospheric pressure. Due to the cylindrical symmetry an adequate 2-D representation of the otherwise 3-dimensional structure is used. A helium-oxygen chemistry reaction scheme is applied. We study the effect of secondary electrons emitted at the inner electrode as well as the inserted dielectric tube and discuss their impact on the discharge behavior. We conclude that a proper choice of materials can improve the desired mode of operation of such plasma jets in terms of materials and surface processing.

  16. Atmospheric-pressure plasma-irradiation inhibits mouse embryonic stem cell differentiation to mesoderm and endoderm but promotes ectoderm differentiation

    Science.gov (United States)

    Miura, Taichi; Hamaguchi, Satoshi; Nishihara, Shoko

    2016-04-01

    Recently, various effects of low-temperature atmospheric-pressure plasma irradiation on living cells have been demonstrated, such as tissue sterilization, blood coagulation, angiogenesis, wound healing, and tumor elimination. However, the effect of plasma-irradiation on the differentiation of mouse embryonic stem cells (mESCs) has not yet been clarified. A large number of reactive species are generated by plasma-irradiation in medium, of which hydrogen peroxide (H2O2) is one of the main species generated. Here, we investigated the effect of plasma-irradiation on the differentiation of mESCs using an embryoid body (EB) formation assay with plasma-irradiated medium or H2O2-supplemented non-irradiated medium. Our findings demonstrated that plasma-irradiated medium potently inhibits the differentiation from mESCs to mesoderm and endoderm by inhibiting Wnt signaling as determined by quantitative polymerase chain reaction and immunoblotting analyses. In contrast, both the plasma-irradiated medium and H2O2-supplemented non-irradiated medium enhanced the differentiation to epiblastoid, ectodermal, and neuronal lineages by activation of fibroblast growth factor 4 (FGF4) signaling, suggesting that these effects are caused by the H2O2 generated by plasma-irradiation in medium. However, in each case, the differentiation to glial cells remained unaffected. This study is the first demonstration that plasma-irradiation affects the differentiation of mESCs by the regulation of Wnt and FGF4 signaling pathways.

  17. Differential Influence of Components Resulting from Atmospheric-Pressure Plasma on Integrin Expression of Human HaCaT Keratinocytes

    Directory of Open Access Journals (Sweden)

    Beate Haertel

    2013-01-01

    Full Text Available Adequate chronic wound healing is a major problem in medicine. A new solution might be non-thermal atmospheric-pressure plasma effectively inactivating microorganisms and influencing cells in wound healing. Plasma components as, for example, radicals can affect cells differently. HaCaT keratinocytes were treated with Dielectric Barrier Discharge plasma (DBD/air, DBD/argon, ozone or hydrogen peroxide to find the components responsible for changes in integrin expression, intracellular ROS formation or apoptosis induction. Dependent on plasma treatment time reduction of recovered cells was observed with no increase of apoptotic cells, but breakdown of mitochondrial membrane potential. DBD/air plasma increased integrins and intracellular ROS. DBD/argon caused minor changes. About 100 ppm ozone did not influence integrins. Hydrogen peroxide caused similar effects compared to DBD/air plasma. In conclusion, effects depended on working gas and exposure time to plasma. Short treatment cycles did neither change integrins nor induce apoptosis or ROS. Longer treatments changed integrins as important for influencing wound healing. Plasma effects on integrins are rather attributed to induction of other ROS than to generation of ozone. Changes of integrins by plasma may provide new solutions of improving wound healing, however, conditions are needed which allow initiating the relevant influence on integrins without being cytotoxic to cells.

  18. Differential influence of components resulting from atmospheric-pressure plasma on integrin expression of human HaCaT keratinocytes.

    Science.gov (United States)

    Haertel, Beate; Straßenburg, Susanne; Oehmigen, Katrin; Wende, Kristian; von Woedtke, Thomas; Lindequist, Ulrike

    2013-01-01

    Adequate chronic wound healing is a major problem in medicine. A new solution might be non-thermal atmospheric-pressure plasma effectively inactivating microorganisms and influencing cells in wound healing. Plasma components as, for example, radicals can affect cells differently. HaCaT keratinocytes were treated with Dielectric Barrier Discharge plasma (DBD/air, DBD/argon), ozone or hydrogen peroxide to find the components responsible for changes in integrin expression, intracellular ROS formation or apoptosis induction. Dependent on plasma treatment time reduction of recovered cells was observed with no increase of apoptotic cells, but breakdown of mitochondrial membrane potential. DBD/air plasma increased integrins and intracellular ROS. DBD/argon caused minor changes. About 100 ppm ozone did not influence integrins. Hydrogen peroxide caused similar effects compared to DBD/air plasma. In conclusion, effects depended on working gas and exposure time to plasma. Short treatment cycles did neither change integrins nor induce apoptosis or ROS. Longer treatments changed integrins as important for influencing wound healing. Plasma effects on integrins are rather attributed to induction of other ROS than to generation of ozone. Changes of integrins by plasma may provide new solutions of improving wound healing, however, conditions are needed which allow initiating the relevant influence on integrins without being cytotoxic to cells.

  19. Utilizing the micron sized non-thermal atmospheric pressure plasma inside the animal body for the tumor treatment application.

    Science.gov (United States)

    Mirpour, Shahriar; Piroozmand, Somayeh; Soleimani, Neda; Jalali Faharani, Neda; Ghomi, Hamidreza; Fotovat Eskandari, Hoda; Sharifi, Ali Mohammad; Mirpour, Sahar; Eftekhari, Mohammad; Nikkhah, Maryam

    2016-07-07

    This study aimed to evaluate the effects of micron sized non-thermal atmospheric pressure plasma inside the animal body on breast cancer tumor. The μ-plasma jet consists of micron sized hollow tube in which pure helium gas is ionized by high voltage (4 kV) and high frequency (6 kHz). The efficiency of the plasma treatment in killing cancer cells was first investigated by cell viability measurements of treated 4T1 cells using flow cytometry and cell cycle analysis. For exploration of the in vivo effects of the plasma treatment, the BALB/c mice inoculated by 4T1 cell lines were exposed subcutaneously to plasma for 3 minutes. In addition, H&E staining, TUNEL and Western blotting assays were performed in order to observed the effects of the non-thermal plasma on the tumor cells. The results showed that the efficiency of the plasma in suppression of the tumor growth is comparable to that of a typical chemotherapy drug. Moreover, the results indicated that the plasma induces apoptosis in the tumor tissue and increases the ratio of the apoptotic to anti-apoptotic protein expression. We believe that these findings presented herein may extend our knowledge of the mechanisms by which the plasma exerts its promising anti-cancer effects.

  20. Investigation on the effects of the atmospheric pressure plasma on wound healing in diabetic rats

    Science.gov (United States)

    Fathollah, Sara; Mirpour, Shahriar; Mansouri, Parvin; Dehpour, Ahmad Reza; Ghoranneviss, Mahmood; Rahimi, Nastaran; Safaie Naraghi, Zahra; Chalangari, Reza; Chalangari, Katalin Martits

    2016-02-01

    It is estimated that 15 percent of individuals with diabetes mellitus suffer from diabetic ulcers worldwide. The aim of this study is to present a non-thermal atmospheric plasma treatment as a novel therapy for diabetic wounds. The plasma consists of ionized helium gas that is produced by a high-voltage (8 kV) and high-frequency (6 kHz) power supply. Diabetes was induced in rats via an intravascular injection of streptozotocin. The plasma was then introduced to artificial xerograph wounds in the rats for 10 minutes. Immunohistochemistry assays was performed to determine the level of transforming growth factor (TGF-β1) cytokine. The results showed a low healing rate in the diabetic wounds compared with the wound-healing rate in non-diabetic animals (P diabetic rats (P diabetic wounds (P diabetic rats.

  1. Mechanisms of a novel anticancer therapeutic strategy involving atmospheric pressure plasma-mediated apoptosis and DNA strand break formation.

    Science.gov (United States)

    Chung, Woo-Hyun

    2016-01-01

    Atmospheric pressure plasma has been developed for a variety of biomedical applications due to its chemically reactive components. Recently, the plasma has emerged as a promising novel cancer therapy based on its ability to selectively ablate cancer cells while leaving normal cells essentially unaffected. The therapeutic effect of plasma is attributed to intracellular generation of reactive oxygen/nitrogen species (ROS/RNS) leading to mitochondria-mediated apoptosis and to activation of the DNA damage checkpoint signaling pathway via severe DNA strand break formation. However, the biochemical mechanisms responsible for appropriate activation of these physiological events and which pathway is more crucial for plasma-mediated cytotoxicity have not been clarified. Understanding the molecular link between ROS/RNS-mediated apoptosis and DNA damage-involved chromosome instability is critical for the development of more efficacious therapeutic strategies for selective killing of diverse cancer cells.

  2. Wearable Atmospheric Pressure Plasma Fabrics Produced by Knitting Flexible Wire Electrodes for the Decontamination of Chemical Warfare Agents

    Science.gov (United States)

    Jung, Heesoo; Seo, Jin Ah; Choi, Seungki

    2017-01-01

    One of the key reasons for the limited use of atmospheric pressure plasma (APP) is its inability to treat non-flat, three-dimensional (3D) surface structures, such as electronic devices and the human body, because of the rigid electrode structure required. In this study, a new APP system design—wearable APP (WAPP)—that utilizes a knitting technique to assemble flexible co-axial wire electrodes into a large-area plasma fabric is presented. The WAPP device operates in ambient air with a fully enclosed power electrode and grounded outer electrode. The plasma fabric is flexible and lightweight, and it can be scaled up for larger areas, making it attractive for wearable APP applications. Here, we report the various plasma properties of the WAPP device and successful test results showing the decontamination of toxic chemical warfare agents, namely, mustard (HD), soman (GD), and nerve (VX) agents.

  3. Detection of HO2 in an atmospheric pressure plasma jet using optical feedback cavity-enhanced absorption spectroscopy

    Science.gov (United States)

    Gianella, Michele; Reuter, Stephan; Lawry Aguila, Ana; Ritchie, Grant A. D.; van Helden, Jean-Pierre H.

    2016-11-01

    Cold non-equilibrium atmospheric pressure plasma jets are increasingly applied in material processing and plasma medicine. However, their small dimensions make diagnosing the fluxes of generated species a challenge. Here we report on the detection of the hydroperoxyl radical, HO2, in the effluent of a plasma jet by the use of optical feedback cavity-enhanced absorption spectroscopy. The spectrometer has a minimum detectable absorption coefficient {α }\\min of 2.25× {10}-10 cm-1 with a 100 second acquisition, equivalent to 5.5× {10}12 {{cm}}-3 of HO2 (under ideal conditions). Concentrations in the range of (3.1-7.8) × 1013 cm-3 were inferred in the 4 mm wide effluent of the plasma jet.

  4. The effects of added hydrogen on a helium atmospheric-pressure plasma jet ambient desorption/ionization source.

    Science.gov (United States)

    Wright, Jonathan P; Heywood, Matthew S; Thurston, Glen K; Farnsworth, Paul B

    2013-03-01

    We present mass spectrometric data demonstrating the effect that hydrogen has on a helium-based dielectric-barrier discharge (DBD) atmospheric-pressure plasma jet used as an ambient desorption/ionization (ADI) source. The addition of 0.9 % hydrogen to the helium support gas in a 35-W plasma jet increased signals for a range of test analytes, with enhancement factors of up to 68, without proportional increases in background levels. The changes in signal levels result from a combination of changes in the desorption kinetics from the surface and increased ion production in the gas phase. The enhancement in ADI-MS performance despite the quenching of key plasma species reported in earlier studies suggests that ionization with a H2/He plasma jet is the result of an alternate mechanism involving the direct generation of ionized hydrogen.

  5. Effect of Atmospheric-Pressure Cold Plasma on Pathogenic Oral Biofilms and In Vitro Reconstituted Oral Epithelium.

    Science.gov (United States)

    Delben, Juliana Aparecida; Zago, Chaiene Evelin; Tyhovych, Natalia; Duarte, Simone; Vergani, Carlos Eduardo

    2016-01-01

    Considering the ability of atmospheric-pressure cold plasma (ACP) to disrupt the biofilm matrix and rupture cell structure, it can be an efficient tool against virulent oral biofilms. However, it is fundamental that ACP does not cause damage to oral tissue. So, this study evaluated (1) the antimicrobial effect of ACP on single- and dual-species biofilms of Candida albicans and Staphylococcus aureus as well as (2) the biological safety of ACP on in vitro reconstituted oral epithelium. Standardized cell suspensions of each microorganism were prepared for biofilm culture on acrylic resin discs at 37°C for 48 hours. The biofilms were submitted to ACP treatment at 10 mm of plasma tip-to-sample distance during 60 seconds. Positive controls were penicillin G and fluconazole for S. aureus and C. albicans, respectively. The biofilms were analyzed through counting of viable colonies, confocal laser scanning microscopy, scanning electron microscopy and fluorescence microscopy for detection of reactive oxygen species. The in vitro reconstituted oral epithelium was submitted to similar ACP treatment and analyzed through histology, cytotoxocity test (LDH release), viability test (MTT assay) and imunnohistochemistry (Ki67 expression). All plasma-treated biofilms presented significant log10 CFU/mL reduction, alteration in microorganism/biofilm morphology, and reduced viability in comparison to negative and positive controls. In addition, fluorescence microscopy revealed presence of reactive oxygen species in all plasma-treated biofilms. Low cytotoxicity and high viability were observed in oral epithelium of negative control and plasma group. Histology showed neither sign of necrosis nor significant alteration in plasma-treated epithelium. Ki67-positive cells revealed maintenance of cell proliferation in plasma-treated epithelium. Atmospheric-pressure cold plasma is a promissing approach to eliminate single- and dual-species biofilms of C. albicans and S. aureus without having

  6. Effect of Atmospheric-Pressure Cold Plasma on Pathogenic Oral Biofilms and In Vitro Reconstituted Oral Epithelium.

    Directory of Open Access Journals (Sweden)

    Juliana Aparecida Delben

    Full Text Available Considering the ability of atmospheric-pressure cold plasma (ACP to disrupt the biofilm matrix and rupture cell structure, it can be an efficient tool against virulent oral biofilms. However, it is fundamental that ACP does not cause damage to oral tissue. So, this study evaluated (1 the antimicrobial effect of ACP on single- and dual-species biofilms of Candida albicans and Staphylococcus aureus as well as (2 the biological safety of ACP on in vitro reconstituted oral epithelium. Standardized cell suspensions of each microorganism were prepared for biofilm culture on acrylic resin discs at 37°C for 48 hours. The biofilms were submitted to ACP treatment at 10 mm of plasma tip-to-sample distance during 60 seconds. Positive controls were penicillin G and fluconazole for S. aureus and C. albicans, respectively. The biofilms were analyzed through counting of viable colonies, confocal laser scanning microscopy, scanning electron microscopy and fluorescence microscopy for detection of reactive oxygen species. The in vitro reconstituted oral epithelium was submitted to similar ACP treatment and analyzed through histology, cytotoxocity test (LDH release, viability test (MTT assay and imunnohistochemistry (Ki67 expression. All plasma-treated biofilms presented significant log10 CFU/mL reduction, alteration in microorganism/biofilm morphology, and reduced viability in comparison to negative and positive controls. In addition, fluorescence microscopy revealed presence of reactive oxygen species in all plasma-treated biofilms. Low cytotoxicity and high viability were observed in oral epithelium of negative control and plasma group. Histology showed neither sign of necrosis nor significant alteration in plasma-treated epithelium. Ki67-positive cells revealed maintenance of cell proliferation in plasma-treated epithelium. Atmospheric-pressure cold plasma is a promissing approach to eliminate single- and dual-species biofilms of C. albicans and S. aureus

  7. Comparison of Structures and Properties between Wool and Ramie Fibers Treated by Atmospheric Pressure Ar and Ar/O2 Plasma

    Institute of Scientific and Technical Information of China (English)

    WANG Yue-ping; XU Xiang-yu; WANG Shou-guo; ZHANG Xiao-dan; ZHAO Ling-li; SHI Li-min; GAO Xu-shan

    2009-01-01

    The technique of atmospheric pressure plasma is of value in textile industry. In this paper, argon (Ar) and argon/oxygen (Ar/O2) atmospheric pressure plasma were used to treat wool and ramie fibers. The structures and properties of treated fibers were investigated by means of SEM, XPS, single fiber tensile tester and so on.The results proved that the effects of plasma treatments depended on structural characteristics of fibers to a great extent, besides conditions of plasma treatment. By atmospheric pressure plasma treatment, wool fiber had significant changes in morphology structure, surface chemical component, mechanic properties and dyeability, while ramie fiber just showed a little change. In additional, Ar/Q2 plasma showed more effective action than argon. And at the beginning of treatment, plasma brought about remarkable effects, which did not increase with prolonging of treat time.

  8. 50-Hz plasma treatment of glass fibre reinforced polyester at atmospheric pressure enhanced by ultrasonic irradiation

    OpenAIRE

    Kusano, Yukihiro; Norrman, Kion; Singh, Shailendra Vikram; Leipold, Frank; Morgen, P.; Bardenshtein, A.; Krebs, N.

    2011-01-01

    Glass fibre reinforced polyester (GFRP) plates are treated using a 50-Hz dielectric barrier discharge at peak-to-peak voltage of 30 kV in helium at atmospheric pressure with and without ultrasonicirradiation to study adhesion improvement. The ultrasonic waves at the fundamental frequency of around 30 kHz with the sound pressure level of approximately 155 dB were introduced vertically to the GFRP surface through a cylindrical waveguide. The polar component of the surface energy was almost unch...

  9. Effects and Mechanism of Atmospheric-Pressure Dielectric Barrier Discharge Cold Plasma on Lactate Dehydrogenase (LDH) Enzyme.

    Science.gov (United States)

    Zhang, Hao; Xu, Zimu; Shen, Jie; Li, Xu; Ding, Lili; Ma, Jie; Lan, Yan; Xia, Weidong; Cheng, Cheng; Sun, Qiang; Zhang, Zelong; Chu, Paul K

    2015-01-01

    Proteins are carriers of biological functions and the effects of atmospheric-pressure non-thermal plasmas on proteins are important to applications such as sterilization and plasma-induced apoptosis of cancer cells. Herein, we report our detailed investigation of the effects of helium-oxygen non-thermal dielectric barrier discharge (DBD) plasmas on the inactivation of lactate dehydrogenase (LDH) enzyme solutions. Circular dichroism (CD) and dynamic light scattering (DLS) indicate that the loss of activity stems from plasma-induced modification of the secondary molecular structure as well as polymerization of the peptide chains. Raising the treatment intensity leads to a reduced alpha-helix content, increase in the percentage of the beta-sheet regions and random sequence, as well as gradually decreasing LDH activity. However, the structure of the LDH plasma-treated for 300 seconds exhibits a recovery trend after storage for 24 h and its activity also increases slightly. By comparing direct and indirect plasma treatments, plasma-induced LDH inactivation can be attributed to reactive species (RS) in the plasma, especially ones with a long lifetime including hydrogen peroxide, ozone, and nitrate ion which play the major role in the alteration of the macromolecular structure and molecular diameter in lieu of heat, UV radiation, and charged particles.

  10. Effects and Mechanism of Atmospheric-Pressure Dielectric Barrier Discharge Cold Plasma on Lactate Dehydrogenase (LDH) Enzyme

    Science.gov (United States)

    Zhang, Hao; Xu, Zimu; Shen, Jie; Li, Xu; Ding, Lili; Ma, Jie; Lan, Yan; Xia, Weidong; Cheng, Cheng; Sun, Qiang; Zhang, Zelong; Chu, Paul K.

    2015-05-01

    Proteins are carriers of biological functions and the effects of atmospheric-pressure non-thermal plasmas on proteins are important to applications such as sterilization and plasma-induced apoptosis of cancer cells. Herein, we report our detailed investigation of the effects of helium-oxygen non-thermal dielectric barrier discharge (DBD) plasmas on the inactivation of lactate dehydrogenase (LDH) enzyme solutions. Circular dichroism (CD) and dynamic light scattering (DLS) indicate that the loss of activity stems from plasma-induced modification of the secondary molecular structure as well as polymerization of the peptide chains. Raising the treatment intensity leads to a reduced alpha-helix content, increase in the percentage of the beta-sheet regions and random sequence, as well as gradually decreasing LDH activity. However, the structure of the LDH plasma-treated for 300 seconds exhibits a recovery trend after storage for 24 h and its activity also increases slightly. By comparing direct and indirect plasma treatments, plasma-induced LDH inactivation can be attributed to reactive species (RS) in the plasma, especially ones with a long lifetime including hydrogen peroxide, ozone, and nitrate ion which play the major role in the alteration of the macromolecular structure and molecular diameter in lieu of heat, UV radiation, and charged particles.

  11. Characterization of atmospheric pressure plasma treated pure cashmere and wool/cashmere textiles: Treatment in air/water vapor mixture

    Energy Technology Data Exchange (ETDEWEB)

    Zanini, Stefano, E-mail: stefano.zanini@mib.infn.it [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy); Grimoldi, Elisa [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy); Citterio, Attilio [Politecnico di Milano, Dipartimento di Chimica, Materiali ed Ingegneria Chimica “G. Natta”, Via Mancinelli 7, I-20131 Milano (Italy); Riccardi, Claudia, E-mail: riccardi@mib.infn.it [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy)

    2015-09-15

    Highlights: • We treated cashmere and wool/cashmere textiles with atmospheric pressure plasma. • Wettability of the fabrics was increased. • The increment in wettability derived from a surface oxidation of the fibers. • Only minor etching effects were observed with scanning electron microscopy. - Abstract: We performed atmospheric pressure plasma treatments of pure cashmere and wool/cashmere textiles with a dielectric barrier discharge (DBD) in humid air (air/water vapor mixtures). Treatment parameters have been optimized in order to enhance the wettability of the fabrics without changing their bulk properties as well as their touch. A deep characterization has been performed to study the wettability, the surface morphologies, the chemical composition and the mechanical properties of the plasma treated textiles. The chemical properties of the plasma treated samples were investigated with attenuated total reflectance Fourier transform infrared (FTIR/ATR) spectroscopy and X-ray photoelectron microscopy (XPS). The analyses reveal a surface oxidation of the treated fabrics, which enhances their surface wettability. Morphological characterization of the treated fibers with scanning electron microscopy (SEM) reveals minor etching effects, an essential feature for the maintenance of the textile softness.

  12. Development of a radio frequency atmospheric pressure plasma jet for diamond-like carbon coatings on stainless steel substrates

    Science.gov (United States)

    Sohbatzadeh, F.; Samadi, O.; Siadati, S. N.; Etaati, G. R.; Asadi, E.; Safari, R.

    2016-10-01

    In this paper, an atmospheric pressure plasma jet with capacitively coupled radio frequency discharge was developed for diamond-like carbon (DLC) coatings on stainless steel substrates. The plasma jet was generated by argon-methane mixture and its physical parameters were investigated. Relation between the plasma jet length and width of the powered electrode was discussed. Optical and electrical characteristics were studied by optical emission spectroscopy, voltage and current probes, respectively. The evolutions of various species like ArI, C2 and CH along the jet axis were investigated. Electron temperature and density were estimated by Boltzmann plot method and Saha-Boltzmann equation, respectively. Finally, a diamond-like carbon coating was deposited on stainless steel-304 substrates by the atmospheric pressure radio frequency plasma jet in ambient air. Raman spectroscopy, scanning electron microscopy (SEM), atomic force microscopy and Vickers hardness test were used to study the deposited films. The length of the jet was increased by increasing the width of the powered electrode. The estimated electron temperature and density were 1.43 eV and 1.39 × 1015 cm-3, respectively. Averaged Vicker's hardness of the coated sample was three times greater than that of the substrate. The SEM images of the deposited thin films revealed a 4.5 μm DLC coated for 20 min.

  13. Atmospheric pressure plasma jet treatment evokes transient oxidative stress in HaCaT keratinocytes and influences cell physiology.

    Science.gov (United States)

    Wende, Kristian; Straßenburg, Susanne; Haertel, Beate; Harms, Manuela; Holtz, Sarah; Barton, Annemarie; Masur, Kai; von Woedtke, Thomas; Lindequist, Ulrike

    2014-04-01

    Modern non-thermal atmospheric pressure plasma sources enable controllable interaction with biological systems. Their future applications - e.g. wound management - are based on their unique mixture of reactive components sparking both stimulatory as well as inhibitory processes. To gain detailed understanding of plasma-cell interaction and with respect to risk awareness, key mechanisms need to be identified. This study focuses on the impact of an argon non-thermal atmospheric pressure plasma jet (kINPen 09) on human HaCaT keratinocytes. With increasing duration, cell viability decreased. In accordance, cells accumulated in G2/M phase within the following 24 h. DNA single-strand breaks were detected immediately after treatment and receded in the aftermath, returning to control levels after 24 h. No directly plasma-related DNA double-strand breaks were detected over the same time. Concurrently, DNA synthesis decreased. Coincident with treatment time, an increase in intracellular 2',7'-dichlorodihydrofluorescein diacetate (H(2)DCFDA) conversion increased reactive oxygen species (ROS) levels. The radical scavenging activity of culture medium crucially influenced these effects. Thus, ROS changed DNA integrity, and the effectiveness of cellular defence mechanisms characterises the interaction of non-thermal plasma and eukaryotic cells. Effects were time-dependent, indicating an active response of the eukaryotic cells. Hence, a stimulation of eukaryotic cells using short-term non-thermal plasma treatment seems possible, eg in the context of chronic wound care. Long-term plasma treatments stopped in cell proliferation and apoptosis, which might be relevant in controlling neoplastic conditions.

  14. Growth enhancement effects of radish sprouts: atmospheric pressure plasma irradiation vs. heat shock

    Science.gov (United States)

    Sarinont, T.; Amano, T.; Kitazaki, S.; Koga, K.; Uchida, G.; Shiratani, M.; Hayashi, N.

    2014-06-01

    We compare growth enhancement effects due to atmospheric air dielectric barrier discharge plasma irradiation and heat shock to seeds of radish sprouts (Raphanus sativus L.). Interactions between radicals and seeds in a short duration of 3 min. lead to the growth enhancement of radish sprouts in a long term of 7 days and the maximum average length is 3.7 times as long as that of control. The growth enhancement effects become gradually weak with time, and hence the ratio of the average length for plasma irradiation to that for control decreases from 3.7 for the first day to 1.3 for 7 day. The average length for heat shock of 60°C for 10 min. and 100°C for 3 min. is longer than that for control, and the maximum average length is 1.3 times as long as that of control. Heat shock has little contribution to the growth enhancement due to plasma irradiation, because the maximum temperature due to plasma irradiation is less than 60°C.

  15. Effects of atmospheric pressure cold plasma on human hepatocarcinoma cell and its 5-fluorouracil resistant cell line

    Science.gov (United States)

    Yang, H.; Lu, R.; Xian, Y.; Gan, L.; Lu, X.; Yang, X.

    2015-12-01

    Atmospheric pressure cold plasma showed selective killing efficiency on cancer cells in vitro and in vivo, which makes plasma a potential option for cancer therapy. However, the plasma effects on chemotherapeutic drugs-resistant cells are rarely to be found. In this paper, the effects of plasma on human hepatocellular carcinoma Bel7402 cells and 5-fluorouracil (5-FU) resistant Bel7402/5FU cells were intensively investigated. The results showed that plasma induced superior toxicity to Bel7402 cells compared with Bel7402/5FU cells. Incubation with plasma-treated medium for 20 s induced more than 85% death rate in Bel7402 cells, while the same death ratio was achieved when Bel7402/5FU cells were treated for as long as 300 s. The hydrogen peroxide in the medium played a leading role in the cytotoxicity effects. Further studies implicated that when the treatment time was shorter than 60 s, the depolarization of mitochondrial membrane potential and apoptosis occurred through the intracellular reactive oxygen species accumulation in Bel7402 cells. Molecular analysis showed an increase in the transcription factor activity for AP-1, NF-кB, and p53 in Bel7402 cells. No obvious damage could be detected in plasma-treated Bel7402/5FU cells due to the strong intracellular reactive oxygen stress scavenger system.

  16. Effects of atmospheric pressure cold plasma on human hepatocarcinoma cell and its 5-fluorouracil resistant cell line

    Energy Technology Data Exchange (ETDEWEB)

    Yang, H.; Gan, L.; Yang, X., E-mail: luxinpei@hotmail.com, E-mail: yangxl@mail.hust.edu.cn [College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Lu, R. [School Hospital of Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Xian, Y.; Lu, X., E-mail: luxinpei@hotmail.com, E-mail: yangxl@mail.hust.edu.cn [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

    2015-12-15

    Atmospheric pressure cold plasma showed selective killing efficiency on cancer cells in vitro and in vivo, which makes plasma a potential option for cancer therapy. However, the plasma effects on chemotherapeutic drugs-resistant cells are rarely to be found. In this paper, the effects of plasma on human hepatocellular carcinoma Bel7402 cells and 5-fluorouracil (5-FU) resistant Bel7402/5FU cells were intensively investigated. The results showed that plasma induced superior toxicity to Bel7402 cells compared with Bel7402/5FU cells. Incubation with plasma-treated medium for 20 s induced more than 85% death rate in Bel7402 cells, while the same death ratio was achieved when Bel7402/5FU cells were treated for as long as 300 s. The hydrogen peroxide in the medium played a leading role in the cytotoxicity effects. Further studies implicated that when the treatment time was shorter than 60 s, the depolarization of mitochondrial membrane potential and apoptosis occurred through the intracellular reactive oxygen species accumulation in Bel7402 cells. Molecular analysis showed an increase in the transcription factor activity for AP-1, NF-kB, and p53 in Bel7402 cells. No obvious damage could be detected in plasma-treated Bel7402/5FU cells due to the strong intracellular reactive oxygen stress scavenger system.

  17. Removal of naturally grown human biofilm with an atmospheric pressure plasma jet: An in-vitro study.

    Science.gov (United States)

    Jablonowski, Lukasz; Fricke, Katja; Matthes, Rutger; Holtfreter, Birte; Schlüter, Rabea; von Woedtke, Thomas; Weltmann, Klaus-Dieter; Kocher, Thomas

    2016-08-19

    The removal of biofilm is a prerequisite for a successful treatment of biofilm-associated diseases. In this study, we compared the feasibility of an atmospheric pressure plasma device with a sonic powered brush to remove naturally grown supragingival biofilm from extracted teeth. Twenty-four periodontally hopeless teeth were extracted. Argon jet plasma with an oxygen admixture of 1 vol% and a sonically driven brush were used to remove biofilm with application times of 60 s, 180 s and 300 s. The treatment efficiency was assessed with light microscopy, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The highest biofilm removal rate was observed after an application time of 180 s/300 s with the sonic brush (80.4%/86.2%), plasma (75.5%/89.0%). These observations were confirmed by SEM. According to XPS analysis, plasma treatment decreased the amount of carbon and nitrogen, indicative of an extensive removal of proteins. Plasma treatment of naturally grown biofilm resulted in an effective cleaning of the tooth surface and was comparable to mechanical treatment. Treatment time had a significant influence on plaque reduction. These results showed that plasma could be a useful adjuvant treatment modality in cases where biofilm removal or reduction plays a decisive role, such as periodontitis and peri-implantitis. Plasma-treated biofilm on an extracted tooth.

  18. On the design and characterization of a new cold atmospheric pressure plasma jet and its applications on cancer cells treatment.

    Science.gov (United States)

    Akhlaghi, Morteza; Rajayi, Hajar; Mashayekh, Amir Shahriar; Khani, Mohammadreza; Hassan, Zuhair Mohammad; Shokri, Babak

    2015-06-23

    In this paper, a new configuration of a cold atmospheric pressure plasma jet has been designed and constructed. Poly-methyl-methacrylate was used as a new dielectric in this configuration which in comparison to other dielectrics is inexpensive, more resistant against break, and also more shapeable. Then, the plasma jet parameters such as plume temperature, rotational and vibrational temperatures, power, electrical behavior (voltage and current profile), electron density, and the produced reactive species were characterized. In order to determine the jet temperature and the amount of reactive species, effects of applied voltage, gas flow rate, and distance from the nozzle were studied. The power of the jet was specified using Lissajous curve approach. The plume temperature of the plasma jet was about the room temperature. Optical emission spectroscopy determined the type of reactive species, and also electron density and its corresponding plasma frequency (~6.4 × 10(13) cm(-3) and 4.52 × 10(11) Hz). Because of producing different reactive species, the device can be used in different applications, especially in plasma medicine. Thus, 4T1 cancer cells were treated using this plasma jet. The results showed that this plasma jet has a great potential to kill one of the most aggressive and resistant cancerous cell lines.

  19. Emission and absorption spectroscopy study of Ar excited states in 13.56 MHz argon plasma operating at sub-atmospheric to atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Li, L. [Department of Applied Physics, Research Unit Plasma Technology, Ghent University, Jozef Plateaustraat 22, Ghent B-9000 (Belgium); Nikiforov, A., E-mail: anton.nikiforov@ugent.be [Department of Applied Physics, Research Unit Plasma Technology, Ghent University, Jozef Plateaustraat 22, Ghent B-9000 (Belgium); Institute of Solution Chemistry of the Russian Academy of Science, Academicheskaya St., 1, Ivanovo, 153045 (Russian Federation); Britun, N. [Chimie des Interactions Plasma-Surface (ChIPS), CIRMAP, Universite de Mons, 23 Place du Parc, B-7000 Mons (Belgium); Snyders, R. [Chimie des Interactions Plasma-Surface (ChIPS), CIRMAP, Universite de Mons, 23 Place du Parc, B-7000 Mons (Belgium); Materia Nova Research Centre, Parc Initialis, B-7000 Mons (Belgium); Leys, C. [Department of Applied Physics, Research Unit Plasma Technology, Ghent University, Jozef Plateaustraat 22, Ghent B-9000 (Belgium)

    2015-05-01

    The densities of metastable and resonant states of Ar atoms are measured in high pressure Ar radio frequency discharge. Resonant absorption spectroscopy for the case of a low pressure spectral lamp and high-pressure plasma absorption lines is implemented for this purpose. The necessary generalizations for the high-pressure resonant absorption method are given. Absolute density of Ar 1s levels obtained at different RF input power and operating pressures are of the order of 10{sup 11} cm{sup −3}, which is in a good agreement with those reported in the literature. The population distribution on the Ar 2p (excited) levels, obtained from the optical emission spectroscopy, reveals strong deviation from thermal equilibrium for these levels in the high-pressure case. The generation of the Ar excited states in the studied discharges is compared to the previously reported results. - Highlights: • Strong non-equilibrium distribution of Ar 2p levels is observed. • The absolute number density of non-radiative Ar 1s states is determined by the easier and low cost spectral-lamp absorption method. • The modified absorption theory of Mitchell and Zemanski was used to obtain the absolute number density of Ar 1s states at high pressure. • The developed RF source with 5 cm long gap can be a possible alternative to micro-plasma working in Ar at atmospheric pressure.

  20. The effect of seed electrons on the repeatability of atmospheric pressure plasma plume propagation. II. Modeling

    Science.gov (United States)

    Chang, L.; Nie, L.; Xian, Y.; Lu, X.

    2016-12-01

    One of the distinguishable features of plasma jets compared with the traditional streamers is their repeatable propagation. As an initial objective, the effect of seed electrons on the repeatability of plasma plume propagation is investigated numerically. Besides residual electrons left from previous pulses, the electrons detached from O2 - ions could also be a significant source of the seed electrons to affect the repeatability of plasma plume propagation when an electronegative gas admixture is presented. In this investigation, a global plasma chemical kinetics model is developed to investigate the temporal evolution of the electron and O2 - ions in the afterglow of a plasma plume driven by microsecond pulse direct current voltages, at a total gas pressure of 2 × 104 Pa or 4 × 103 Pa in helium or helium-oxygen mixtures with an air impurity of 0.025%. In addition, a Monte Carlo technique has been applied to calculate the O2 - detachment rate coefficient. Accordingly, the seed electron density due to detachment from O2 - ions for different percentages of oxygen is obtained. Finally, the minimum seed electron density required for the plasma bullets to propagate in a repeatable mode is obtained according to the critical frequency from the experiments. It is found that the order of minimum seed electron number density required for repeatable propagation mode is independent of oxygen concentrations in the helium-oxygen mixture. It is 10 8 cm - 3 for 20 kPa and 10 7 cm - 3 for 4 kPa. Furthermore, for the helium with an air impurity of 0.025%, the residual electrons left over from previous discharges are the main source of seed electrons. On the other hand, when 0.5% of O2 is added, the detachment of O2 - is the main source of the seed electrons.

  1. Use of molecular beacons for the rapid analysis of DNA damage induced by exposure to an atmospheric pressure plasma jet

    Science.gov (United States)

    Kurita, Hirofumi; Miyachika, Saki; Yasuda, Hachiro; Takashima, Kazunori; Mizuno, Akira

    2015-12-01

    A rapid method for evaluating the damage caused to DNA molecules upon exposure to plasma is demonstrated. Here, we propose the use of a molecular beacon for rapid detection of DNA strand breaks induced by atmospheric pressure plasma jet (APPJ) irradiation. Scission of the molecular beacon by APPJ irradiation leads to separation of the fluorophore-quencher pair, resulting in an increase in fluorescence that directly correlates with the DNA strand breaks. The results show that the increase in fluorescence intensity is proportional to the exposure time and the rate of fluorescence increase is proportional to the discharge power. This simple and rapid method allows the estimation of DNA damage induced by exposure to a non-thermal plasma.

  2. Use of molecular beacons for the rapid analysis of DNA damage induced by exposure to an atmospheric pressure plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, Hirofumi, E-mail: kurita@ens.tut.ac.jp, E-mail: mizuno@ens.tut.ac.jp; Miyachika, Saki; Yasuda, Hachiro; Takashima, Kazunori; Mizuno, Akira, E-mail: kurita@ens.tut.ac.jp, E-mail: mizuno@ens.tut.ac.jp [Department of Environmental and Life Sciences, Toyohashi University of Technology, Aichi 441-8580 (Japan)

    2015-12-28

    A rapid method for evaluating the damage caused to DNA molecules upon exposure to plasma is demonstrated. Here, we propose the use of a molecular beacon for rapid detection of DNA strand breaks induced by atmospheric pressure plasma jet (APPJ) irradiation. Scission of the molecular beacon by APPJ irradiation leads to separation of the fluorophore-quencher pair, resulting in an increase in fluorescence that directly correlates with the DNA strand breaks. The results show that the increase in fluorescence intensity is proportional to the exposure time and the rate of fluorescence increase is proportional to the discharge power. This simple and rapid method allows the estimation of DNA damage induced by exposure to a non-thermal plasma.

  3. Atmospheric-Pressure Cold Plasmas Used to Embed Bioactive Compounds in Matrix Material for Active Packaging of Fruits and Vegetables

    Science.gov (United States)

    Fernandez, Sulmer; Pedrow, Patrick; Powers, Joseph; Pitts, Marvin

    2009-10-01

    Active thin film packaging is a technology with the potential to provide consumers with new fruit and vegetable products-if the film can be applied without deactivating bioactive compounds.Atmospheric pressure cold plasma (APCP) processing can be used to activate monomer with concomitant deposition of an organic plasma polymerized matrix material and to immobilize a bioactive compound all at or below room temperature.Aims of this work include: 1) immobilize an antimicrobial in the matrix; 2) determine if the antimicrobial retains its functionality and 3) optimize the reactor design.The plasma zone will be obtained by increasing the voltage on an electrode structure until the electric field in the feed material (argon + monomer) yields electron avalanches. Results will be described using Red Delicious apples.Prospective matrix precursors are vanillin and cinnamic acid.A prospective bioactive compound is benzoic acid.

  4. In vitro bactericidal efficacy of atmospheric-pressure plasma jet on titanium-based implant infected with Staphylococcus aureus

    Science.gov (United States)

    Park, Young-Ouk; Lee, Chang-Min; Kim, Myung-Sun; Jung, Sang-Chul; Yang, Seong-Won; Kook, Min-Suk; Kim, Byung-Hoon

    2017-01-01

    Staphylococcus aureus is a representative of gram-positive bacteria that causes skin infection, respiratory diseases, and burned tissue infections. The aim of this study was to evaluate the sterilizing efficiency of an atmospheric-pressure plasma jet (APPJ) on S. aureus adhered on a titanium surface. During the APPJ sterilization, the plasma gases used were Ar, Ar+N2, and Ar+O2. With increasing APPJ treatment time, the viability of S. aureus decreased. The addition of O2 gas to Ar gas resulted in a higher sterilizing efficiency than the addition of other groups. Plasma exposure induced bacterial oxidative stress, and it was confirmed that the cell membrane was seriously damaged by the production of reactive oxygen species. Our finding suggests that the APPJ is an effective tool for clinical antimicrobial therapy.

  5. Plasma polymerization of ethylene in an atmospheric pressure-pulsed discharge

    Science.gov (United States)

    Donohoe, K.; Wydeven, T.

    1979-01-01

    The polymerization of ethylene in an atmospheric pressure-pulsed discharge has been studied. Partial pressures of ethylene up to 4 kN/sq m were used with helium as a diluent. Deposition rates (on glass slides) were the same throughout the discharge volume over a wide range of operating conditions. These rates were in the 1-2 A/sec range. The films were clear, soft, and showed good adhesion to the glass substrates. Oligomers large enough to visibly scatter 637.8-nm light were observed in the gas phase under all conditions in which film deposition occurred. The experimental results suggest that Brownian diffusion of these oligomers was the rate-limiting step in the film deposition process.

  6. Exploration of surface hydrophilic properties on AISI 304 stainless steel and silicon wafer against aging after atmospheric pressure plasma treatment

    Science.gov (United States)

    Chuang, Shang-I.; Duh, Jenq-Gong

    2014-11-01

    The aim of this work is to seek the enhanced surface hydrophilic properties on AISI 304 stainless steel and silicon wafer after atmospheric pressure plasma treatment using a specifically designed atmospheric pressure plasma jet. The aging tendency of surface hydrophilic property under air is highlighted. It is concluded that both of the silicon wafer and stainless steel treated with plasma generated from supply gas of argon 15 slm mixed with oxygen 40 sccm shows a better tendency on remaining high water contact angle as compared to that with pure argon and nitrogen addition. Additional peaks of O I (777, 844 nm), O II (408 nm) are detected by optical emission spectroscope indicating the presence of the oxygen radicals and ionic species, which interact with surfaces and thus contribute to low water contact angle (WCA) surfaces. Moreover, the result acquired from X-ray photoelectron spectroscopy (XPS) indicates that the increase in the oxygen-related bonding exhibits a better contribution on remaining high surface energy over a period of time.

  7. Photocatalytic Anatase TiO2 Thin Films on Polymer Optical Fiber Using Atmospheric-Pressure Plasma.

    Science.gov (United States)

    Baba, Kamal; Bulou, Simon; Choquet, Patrick; Boscher, Nicolas D

    2017-04-06

    Due to the undeniable industrial advantages of low-temperature atmospheric-pressure plasma processes, such as low cost, low temperature, easy implementation, and in-line process capabilities, they have become the most promising next-generation candidate system for replacing thermal chemical vapor deposition or wet chemical processes for the deposition of functional coatings. In the work detailed in this article, photocatalytic anatase TiO2 thin films were deposited at a low temperature on polymer optical fibers using an atmospheric-pressure plasma process. This method overcomes the challenge of forming crystalline transition metal oxide coatings on polymer substrates by using a dry and up-scalable method. The careful selection of the plasma source and the titanium precursor, i.e., titanium ethoxide with a short alkoxy group, allowed the deposition of well-adherent, dense, and crystalline TiO2 coatings at low substrate temperature. Raman and XRD investigations showed that the addition of oxygen to the precursor's carrier gas resulted in a further increase of the film's crystallinity. Furthermore, the films deposited in the presence of oxygen exhibited a better photocatalytic activity toward methylene blue degradation assumedly due to their higher amount of photoactive {101} facets.

  8. Benzylammonium Thermometer Ions: Internal Energies of Ions Formed by Low Temperature Plasma and Atmospheric Pressure Chemical Ionization.

    Science.gov (United States)

    Stephens, Edward R; Dumlao, Morphy; Xiao, Dan; Zhang, Daming; Donald, William A

    2015-12-01

    The extent of internal energy deposition upon ion formation by low temperature plasma and atmospheric pressure chemical ionization was investigated using novel benzylammonium thermometer ions. C-N heterolytic bond dissociation enthalpies of nine 4-substituted benzylammoniums were calculated using CAM-B3LYP/6-311++G(d,p), which was significantly more accurate than B3LYP/6-311++G(d,p), MP2/6-311++G(d,p), and CBS-QB3 for calculating the enthalpies of 20 heterolytic dissociation reactions that were used to benchmark theory. All 4-substituted benzylammonium thermometer ions fragmented by a single pathway with comparable dissociation entropies, except 4-nitrobenzylammonium. Overall, the extent of energy deposition into ions formed by low temperature plasma was significantly lower than those formed by atmospheric pressure chemical ionization under these conditions. Because benzylamines are volatile, this new suite of thermometer ions should be useful for investigating the extent of internal energy deposition during ion formation for a wide range of ionization methods, including plasma, spray and laser desorption-based techniques. Graphical Abstract ᅟ.

  9. Decontamination of Aspergillus flavus and Aspergillus parasiticus spores on hazelnuts via atmospheric pressure fluidized bed plasma reactor.

    Science.gov (United States)

    Dasan, Beyhan Gunaydin; Mutlu, Mehmet; Boyaci, Ismail Hakki

    2016-01-04

    In this study, an atmospheric pressure fluidized bed plasma (APFBP) system was designed and its decontamination effect on aflatoxigenic fungi (Aspergillus flavus and Aspergillus parasiticus) on the surface of hazelnuts was investigated. Hazelnuts were artificially contaminated with A. flavus and A. parasiticus and then were treated with dry air plasma for up to 5min in the APFBP system at various plasma parameters. Significant reductions of 4.50 log (cfu/g) in A. flavus and 4.19 log (cfu/g) in A. parasiticus were achieved after 5min treatments at 100% V - 25kHz (655W) by using dry air as the plasma forming gas. The decontamination effect of APFBP on A. flavus and A. parasiticus spores inoculated on hazelnuts was increased with the applied reference voltage and the frequency. No change or slight reductions were observed in A. flavus and A. parasiticus load during the storage of plasma treated hazelnuts whereas on the control samples fungi continued to grow under storage conditions (30days at 25°C). Temperature change on hazelnut surfaces in the range between 35 and 90°C was monitored with a thermal camera, and it was demonstrated that the temperature increase taking place during plasma treatment did not have a lethal effect on A. flavus and A. parasiticus spores. The damage caused by APFBP treatment on Aspergillus spp. spores was also observed by scanning electron microscopy.

  10. An atmospheric-pressure cold plasma leads to apoptosis in Saccharomyces cerevisiae by accumulating intracellular reactive oxygen species and calcium

    Science.gov (United States)

    Ma, R. N.; Feng, H. Q.; Liang, Y. D.; Zhang, Q.; Tian, Y.; Su, B.; Zhang, J.; Fang, J.

    2013-07-01

    A non-thermal plasma is known to induce apoptosis of various cells but the mechanism is not yet clear. A eukaryotic model organism Saccharomyces cerevisiaewas used to investigate the cellular and biochemical regulations of cell apoptosis and cell cycle after an atmospheric-pressure cold plasma treatment. More importantly, intracellular calcium (Ca2+) was first involved in monitoring the process of plasma-induced apoptosis in this study. We analysed the cell apoptosis and cell cycle by flow cytometry and observed the changes in intracellular reactive oxygen species (ROS) and Ca2+ concentration, cell mitochondrial membrane potential (Δψm) as well as nuclear DNA morphology via fluorescence staining assay. All experimental results indicated that plasma-generated ROS leads to the accumulation of intracellular ROS and Ca2+ that ultimately contribute to apoptosis associated with cell cycle arrest at G1 phase through depolarization of Δψm and fragmenting nuclear DNA. This work provides a novel insight into the physical and biological mechanism of apoptosis induced by a plasma which could benefit for promoting the development of plasmas applied to cancer therapy.

  11. A comparison between micro hollow cathode discharges and atmospheric pressure plasma jets in Ar/O2 gas mixtures

    Science.gov (United States)

    Lazzaroni, C.; Chabert, P.

    2016-12-01

    Using global models, micro hollow cathode discharges (MHCDs) are compared to radiofrequency atmospheric pressure plasma jets (APPJs) in terms of reactive oxygen species (ROS) production. Ar/O2 gas mixtures are investigated, typically with a small percentage of oxygen in argon. The same chemical reaction set, involving 17 species and 128 chemical reactions in the gas phase, is used for both devices, operated in the typical geometries previously published; the APPJ is driven by a radiofrequency voltage across a 1 mm gap, at atmospheric pressure, while the MHCD is driven by a DC voltage source, at 100 Torr and in a 400 μm hole. The MHCD may be operated either in the self-pulsing or in the normal (stationary) regime, depending on the driving voltage. The comparison shows that in both regimes, the MHCD produces larger amounts of \\text{O}2\\ast , while the APPJ produces predominantly reactive oxygen ground state species, \\text{O} and {{\\text{O}}3} . These large differences in ROS composition are mostly due to the higher plasma density produced in the MHCD. The difference in operating pressure is a second order effect.

  12. Cold atmospheric-pressure air plasma treatment of C6 glioma cells: effects of reactive oxygen species in the medium produced by the plasma on cell death

    Science.gov (United States)

    Yuyang, Wang; Cheng, Cheng; Peng, Gao; Shaopeng, Li; Jie, Shen; Yan, Lan; Yongqiang, Yu; Paul, K. Chu

    2017-02-01

    An atmospheric-pressure air plasma is employed to treat C6 glioma cells in vitro. To elucidate on the mechanism causing cell death and role of reactive species (RS) in the medium produced by the plasma, the concentration of the long-lived RS such as hydrogen peroxide, nitrate, and ozone in the plasma-treated liquid (phosphate-buffered saline solution) is measured. When vitamin C is added to the medium as a ROS quencher, the viability of C6 glioma cells after the plasma treatment is different from that without vitamin C. The results demonstrate that reactive oxygen species (ROS) such as H2O2, and O3 constitute the main factors for inactivation of C6 glioma cells and the reactive nitrogen species (RNS) may only play an auxiliary role in cell death.

  13. Orientating layers with adjustable pretilt angles for liquid crystals deposited by a linear atmospheric pressure plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Jian, Shih-Jie; Kou, Chwung-Shan [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Hwang, Jennchang [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lee, Chein-Dhau; Lin, Wei-Cheng [Material and Chemical Research Laboratories/Industrial Technology Research Institute, Hsinchu 30140, Taiwan (China)

    2013-06-15

    A method for controlling the pretilt angles of liquid crystals (LC) was developed. Hexamethyldisiloxane polymer films were first deposited on indium tin oxide coated glass plates using a linear atmospheric pressure plasma source. The films were subsequently treated with the rubbing method for LC alignment. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy measurements were used to characterize the film composition, which could be varied to control the surface energy by adjusting the monomer feed rate and input power. The results of LC alignment experiments showed that the pretilt angle continuously increased from 0 Degree-Sign to 90 Degree-Sign with decreasing film surface energy.

  14. Synthesis of calcium oxalate crystals in culture medium irradiated with non-equilibrium atmospheric-pressure plasma

    Science.gov (United States)

    Kurake, Naoyuki; Tanaka, Hiromasa; Ishikawa, Kenji; Nakamura, Kae; Kajiyama, Hiroaki; Kikkawa, Fumitaka; Mizuno, Masaaki; Yamanishi, Yoko; Hori, Masaru

    2016-09-01

    Octahedral particulates several tens of microns in size were synthesized in a culture medium irradiated through contact with a plume of non-equilibrium atmospheric-pressure plasma (NEAPP). The particulates were identified in the crystalline phase as calcium oxalate dihydrate (COD). The original medium contained constituents such as NaCl, d-glucose, CaCl2, and NaHCO3 but not oxalate or oxalic acid. The oxalate was clearly synthesized and crystallized in the medium as thermodynamically unstable COD crystals after the NEAPP irradiation.

  15. Surface activation of polyethylene with an argon atmospheric pressure plasma jet: Influence of applied power and flow rate

    Science.gov (United States)

    Van Deynse, A.; Cools, P.; Leys, C.; De Geyter, N.; Morent, R.

    2015-02-01

    Atmospheric pressure plasma technology offers attractive perspectives to alter the surface properties of polymers. Within this context, the surface modification of polyethylene (LDPE) by an argon atmospheric pressure plasma jet (APPJ) is profoundly investigated in this work. The influence of two different parameters (applied power and argon flow rate) on the plasma jet characteristics and the LDPE surface properties is examined in detail. In a first step, the APPJ is electrically and visually characterized and visual inspection of the afterglow clearly shows that mainly a variation in argon flow rate can result in a changing afterglow length. A maximum afterglow length is obtained at an argon flow rate of 1-1.25 slm, while higher gas flows result in turbulence leading to a shorter afterglow. Secondly, the surface modification of LDPE is examined using different analyzing techniques namely water contact angle (WCA) measurements for the wettability, X-ray photoelectron spectroscopy (XPS) for the chemical composition and atomic force microscopy (AFM) for the surface morphology determination. WCA measurements show that by increasing the applied power the wettability of the LDPE increases. Increasing the argon flow rate up to 1.25 slm gives a decrease in WCA value or in other words an increased wettability. From 1.25 slm on, an increase in argon flow rate during plasma treatment decreases the LDPE wettability as can be concluded from the increased WCA values. An increased wettability can be explained by the incorporation of oxygen moieties. By increasing the discharge power, the concentrations of all oxygen containing groups such as Csbnd O, Cdbnd O and Osbnd Cdbnd O increase. Increasing the flow rate up to 1.25 slm results mainly in an increase in Osbnd Cdbnd O groups. However, from a flow rate of 1.25 slm on, the concentration of all oxygen groups again decreases. Based on these results, the appropriate settings for an efficient plasma treatment can easily be selected.

  16. Surface activation of polyethylene with an argon atmospheric pressure plasma jet: Influence of applied power and flow rate

    Energy Technology Data Exchange (ETDEWEB)

    Van Deynse, A., E-mail: Annick.VanDeynse@ugent.be [Department Industrial Technology and Construction, Faculty of Engineering & Architecture, Ghent University, Valentin Vaerwyckweg 1, 9000 Ghent (Belgium); Cools, P., E-mail: Pieter.Cools@ugent.be [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering & Architecture, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Ghent (Belgium); Leys, C., E-mail: Christophe.Leys@ugent.be [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering & Architecture, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Ghent (Belgium); De Geyter, N., E-mail: Nathalie.DeGeyter@ugent.be [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering & Architecture, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Ghent (Belgium); Morent, R., E-mail: Rino.Morent@ugent.be [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering & Architecture, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Ghent (Belgium)

    2015-02-15

    Highlights: • Surface modification of polyethylene by an argon atmospheric pressure plasma jet. • Investigation of the influence of the applied power and argon flow rate. • Turbulence in the gas flow leads to a shorter afterglow. • Turbulence in the gas flow results in a lower wettability of the polyethylene. • Increasing the applied power increases the wettability of the polyethylene. - Abstract: Atmospheric pressure plasma technology offers attractive perspectives to alter the surface properties of polymers. Within this context, the surface modification of polyethylene (LDPE) by an argon atmospheric pressure plasma jet (APPJ) is profoundly investigated in this work. The influence of two different parameters (applied power and argon flow rate) on the plasma jet characteristics and the LDPE surface properties is examined in detail. In a first step, the APPJ is electrically and visually characterized and visual inspection of the afterglow clearly shows that mainly a variation in argon flow rate can result in a changing afterglow length. A maximum afterglow length is obtained at an argon flow rate of 1–1.25 slm, while higher gas flows result in turbulence leading to a shorter afterglow. Secondly, the surface modification of LDPE is examined using different analyzing techniques namely water contact angle (WCA) measurements for the wettability, X-ray photoelectron spectroscopy (XPS) for the chemical composition and atomic force microscopy (AFM) for the surface morphology determination. WCA measurements show that by increasing the applied power the wettability of the LDPE increases. Increasing the argon flow rate up to 1.25 slm gives a decrease in WCA value or in other words an increased wettability. From 1.25 slm on, an increase in argon flow rate during plasma treatment decreases the LDPE wettability as can be concluded from the increased WCA values. An increased wettability can be explained by the incorporation of oxygen moieties. By increasing the

  17. Electron density change of atmospheric-pressure plasmas in helium flow depending on the oxygen/nitrogen ratio of the surrounding atmosphere

    Science.gov (United States)

    Tomita, Kentaro; Urabe, Keiichiro; Shirai, Naoki; Sato, Yuta; Hassaballa, Safwat; Bolouki, Nima; Yoneda, Munehiro; Shimizu, Takahiro; Uchino, Kiichiro

    2016-06-01

    Laser Thomson scattering was applied to an atmospheric-pressure plasma produced in a helium (He) gas flow for measuring the spatial profiles of electron density (n e) and electron temperature (T e). Aside from the He core flow, the shielding gas flow of N2 or synthesized air (\\text{N}2:\\text{O}2 = 4:1) surrounding the He flow was introduced to evaluate the effect of ambient gas components on the plasma parameters, eliminating the effect of ambient humidity. The n e at the discharge center was 2.7 × 1021 m-3 for plasma generated with N2/O2 shielding gas, 50% higher than that generated with N2 shielding.

  18. Feed gas humidity: a vital parameter affecting a cold atmospheric-pressure plasma jet and plasma-treated human skin cells

    Science.gov (United States)

    Winter, J.; Wende, K.; Masur, K.; Iseni, S.; Dünnbier, M.; Hammer, M. U.; Tresp, H.; Weltmann, K.-D.; Reuter, S.

    2013-07-01

    In this study, the effect of feed gas humidity on the reactive component generation of an atmospheric-pressure argon plasma jet and its effect on human skin cells are investigated. Feed gas humidity is identified as one key parameter that strongly influences stability and reproducibility of plasma medical studies. The plasma jet is investigated by absorption spectroscopy in the ultraviolet and infrared spectral region for its ozone production depending on the humidity concentration in the feed gas. By optical emission spectroscopy the dependence of present excited plasma species such as hydroxyl radicals, molecular nitrogen, argon and atomic oxygen on the feed gas humidity is investigated. As an interface layer between the plasma jet effluent and the biological cell, a buffer solution is treated and the hydrogen peroxide (H2O2) production is studied with two independent colorimetric assays as a function of humidity admixture to the feed gas. Ultimately, the effect of varying feed gas humidity on the cell viability of indirect plasma treated adherent HaCAT cells is investigated. The highest viability is found for the driest feed gas condition. Furthermore, this work shows answers for the relevance of unwanted—or intended—feed gas humidity in plasma medical experiments and their comparatively large relevance with respect to ambient humidity. The findings will lead to more reproducible experiments in the field of plasma medicine.

  19. Hydrophilic property of 316L stainless steel after treatment by atmospheric pressure corona streamer plasma using surface-sensitive analyses

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hamarneh, Ibrahim, E-mail: hamarnehibrahim@yahoo.com [Department of Physics, Faculty of Science, Al-Balqa Applied University, Salt 19117 (Jordan); Pedrow, Patrick [School of Electrical Engineering and Computer Science, Washington State University, Pullman, WA 99164 (United States); Eskhan, Asma; Abu-Lail, Nehal [Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164 (United States)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Surface hydrophilic property of surgical-grade 316L stainless steel was enhanced by Ar-O{sub 2} corona streamer plasma treatment. Black-Right-Pointing-Pointer Hydrophilicity, surface morphology, roughness, and chemical composition before and after plasma treatment were evaluated. Black-Right-Pointing-Pointer Contact angle measurements and surface-sensitive analyses techniques, including XPS and AFM, were carried out. Black-Right-Pointing-Pointer Optimum plasma treatment conditions of the SS 316L surface were determined. - Abstract: Surgical-grade 316L stainless steel (SS 316L) had its surface hydrophilic property enhanced by processing in a corona streamer plasma reactor using O{sub 2} gas mixed with Ar at atmospheric pressure. Reactor excitation was 60 Hz ac high-voltage (0-10 kV{sub RMS}) applied to a multi-needle-to-grounded screen electrode configuration. The treated surface was characterized with a contact angle tester. Surface free energy (SFE) for the treated stainless steel increased measurably compared to the untreated surface. The Ar-O{sub 2} plasma was more effective in enhancing the SFE than Ar-only plasma. Optimum conditions for the plasma treatment system used in this study were obtained. X-ray photoelectron spectroscopy (XPS) characterization of the chemical composition of the treated surfaces confirms the existence of new oxygen-containing functional groups contributing to the change in the hydrophilic nature of the surface. These new functional groups were generated by surface reactions caused by reactive oxidation of substrate species. Atomic force microscopy (AFM) images were generated to investigate morphological and roughness changes on the plasma treated surfaces. The aging effect in air after treatment was also studied.

  20. Spectroscopy of reactive species produced by low-energy atmospheric-pressure plasma on conductive target material surface

    Science.gov (United States)

    Yamada, Hiromasa; Sakakita, Hajime; Kato, Susumu; Kim, Jaeho; Kiyama, Satoru; Fujiwara, Masanori; Itagaki, Hirotomo; Okazaki, Toshiya; Ikehara, Sanae; Nakanishi, Hayao; Shimizu, Nobuyuki; Ikehara, Yuzuru

    2016-10-01

    A method for blood coagulation using low-energy atmospheric-pressure plasma (LEAPP) is confirmed as an alternative procedure to reduce tissue damage caused by heat. Blood coagulation using LEAPP behaves differently depending on working gas species; helium is more effective than argon in promoting fast coagulation. To analyse the difference in reactive species produced by helium and argon plasma, spectroscopic measurements were conducted without and with a target material. To compare emissions, blood coagulation experiments using LEAPP for both plasmas were performed under almost identical conditions. Although many kinds of reactive species such as hydroxyl radicals and excited nitrogen molecules were observed with similar intensity in both plasmas, intensities of nitrogen ion molecules and nitric oxide molecules were extremely strong in the helium plasma. It is considered that nitrogen ion molecules were mainly produced by penning ionization by helium metastable. Near the target, a significant increase in the emissions of reactive species is observed. There is a possibility that electron acceleration was induced in a local electric field formed on the surface. However, in argon plasma, emissions from nitrogen ion were not measured even near the target surface. These differences between the two plasmas may be producing the difference in blood coagulation behaviour. To control the surrounding gas of the plasma, a gas-component-controllable chamber was assembled. Filling the chamber with O2/He or N2/He gas mixtures selectively produces either reactive oxygen species or reactive nitrogen species. Through selective treatments, this chamber would be useful in studying the effects of specific reactive species on blood coagulation.

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

    Science.gov (United States)

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

    2017-04-01

    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(Cdbnd O, Csbnd 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.

  2. Surface free radicals detection using molecular scavenging method on black spruce wood treated with cold, atmospheric-pressure plasmas

    Science.gov (United States)

    Hardy, Jean-Michel; Levasseur, Olivier; Vlad, Mirela; Stafford, Luc; Riedl, Bernard

    2015-12-01

    Formation of surface free radicals on wood surfaces during plasma treatment could be an important factor when it comes to wood coating adhesion enhancement. In order to explore this aspect, freshly sanded black spruce (Picea mariana) wood samples were exposed to either plane-to-plane atmospheric-pressure dielectric barrier discharge (AP-DBD) or the flowing afterglow of an AP-DBD and then dipped in a 2,2-diphenyl-1-picrylhydrazyl (DPPH) solution. Wood veneers (extracted to eliminate small molecules prior to each plasma treatment) showed an increase of their reaction rate toward DPPH after treatment in the AP-DBD operated in nominally pure He; a feature ascribed to the plasma-assisted formation of free radicals on the wood surface. Addition of trace amounts (0.1%) of O2 in the He plasma produced a decrease in DPPH reactivity, suggesting that oxygen-spruce interaction during plasma treatment quenches free radicals formation. Similar experiments performed using the flowing afterglow of AP-DBD operated in either N2 or N2/O2 showed that both treatments do not generate significant amount of surface free radicals. This partially results from oxygen-wood interactions due to the open-air configuration of the afterglow reactor.

  3. Gas temperature determination in an argon non-thermal plasma at atmospheric pressure from broadenings of atomic emission lines

    Science.gov (United States)

    Yubero, C.; Rodero, A.; Dimitrijevic, M. S.; Gamero, A.; García, M. C.

    2017-03-01

    In this work a new spectroscopic method, allowing gas temperature determination in argon non-thermal plasmas sustained at atmospheric pressure, is presented. The method is based on the measurements of selected pairs of argon atomic lines (Ar I 603.2 nm/Ar I 549.6 nm, Ar I 603.2 nm/Ar I 522.1 nm, Ar I 549.6 nm/Ar I 522.1 nm). For gas temperature determination using the proposed method, there is no need of knowing the electron density, neither making assumptions on the degree of thermodynamic equilibrium existing in the plasma. The values of the temperatures obtained using this method, have been compared with the rotational temperatures derived from the OH ro-vibrational bands, using both, the well-known Boltzmann-plot technique and the best fitting to simulated ro-vibrational bands. A very good agreement has been found.

  4. High-temperature and high-speed oxidation of 4H-SiC by atmospheric pressure thermal plasma jet

    Science.gov (United States)

    Hanafusa, Hiroaki; Ishimaru, Ryosuke; Higashi, Seiichiro

    2017-04-01

    The application of atmospheric pressure thermal plasma jet (TPJ) annealing to the high-temperature and high-speed thermal oxidation of Si-face of 4H-SiC wafer is reported. A high SiO2 film growth rate of 288 nm min‑1 was obtained at an oxidation temperature of 1640 °C without intentional dry O2 gas feeding. Ambient analysis suggested that ozone generated from oxygen in the ambient air by the plasma irradiation was supplied to the SiC surface. It is implied that a mono-oxygen decomposed from ozone was diffused into the oxide growth interface. As a result, high-speed oxidation occurred by combination of high-temperature TPJ annealing and ozone feeding.

  5. Deposition of SiOx on Metal Surface with a DBD Plasma Gun at Atmospheric Pressure for Corrosion Prevention

    Institute of Scientific and Technical Information of China (English)

    HAN Erli; CHEN Qiang; ZHANG Yuefei; CHEN Fei; GE Yuanjing

    2007-01-01

    In this study,SiOx films were deposited by a dielectric barrier discharge(DBD)plasma gun at an atmospheric pressure.The relationship of the film structures with plasma powers Was investigated by Fourier transform infrared spectroscopy(FTIR),and scanning electron microscope(SEM).It was shown that an uniform and cross-linking structure film was formed by the DBD gun.As an application,the SiOx films were deposited on a carbon steel surface for the anti-corrosion purpose.The experiment was carried out in a 0.1 M NaC1 solution.It Was found that a very good anti-corrosive property was obtained,i.e.,the corrosion rate Was decreased c.a.15 times in 5% NaC1 solution compared to the non-SiOx coated steel,as detected by the potentiodynamic polarization measurement.

  6. Numerically controlled atmospheric-pressure plasma sacrificial oxidation using electrode arrays for improving silicon-on-insulator layer uniformity

    Science.gov (United States)

    Takei, Hiroyasu; Yoshinaga, Keinosuke; Matsuyama, Satoshi; Yamauchi, Kazuto; Sano, Yasuhisa

    2015-01-01

    Silicon-on-insulator (SOI) wafers are important semiconductor substrates in high-performance devices. In accordance with device miniaturization requirements, ultrathin and highly uniform top silicon layers (SOI layers) are required. A novel method involving numerically controlled (NC) atmospheric-pressure plasma sacrificial oxidation using an electrode array system was developed for the effective fabrication of an ultrathin SOI layer with extremely high uniformity. Spatial resolution and oxidation properties are the key factors controlling ultraprecision machining. The controllability of plasma oxidation and the oxidation properties of the resulting experimental electrode array system were examined. The results demonstrated that the method improved the thickness uniformity of the SOI layer over one-sixth of the area of an 8-in. wafer area.

  7. Synthesis of Carbon Nanotubes in Thermal Plasma Reactor at Atmospheric Pressure

    Science.gov (United States)

    Szymanski, Lukasz; Kolacinski, Zbigniew; Wiak, Slawomir; Raniszewski, Grzegorz; Pietrzak, Lukasz

    2017-01-01

    In this paper, a novel approach to the synthesis of the carbon nanotubes (CNTs) in reactors operating at atmospheric pressure is presented. Based on the literature and our own research results, the most effective methods of CNT synthesis are investigated. Then, careful selection of reagents for the synthesis process is shown. Thanks to the performed calculations, an optimum composition of gases and the temperature for successful CNT synthesis in the CVD (chemical vapor deposition) process can be chosen. The results, having practical significance, may lead to an improvement of nanomaterials synthesis technology. The study can be used to produce CNTs for electrical and electronic equipment (i.e., supercapacitors or cooling radiators). There is also a possibility of using them in medicine for cancer diagnostics and therapy. PMID:28336880

  8. The quenching effect of hydrogen on the nitrogen in metastable state in atmospheric-pressure N{sub 2}-H{sub 2} microwave plasma torch

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shou-Zhe, E-mail: lisz@dlut.edu.cn; Zhang, Xin; Chen, Chuan-Jie; Zhang, Jialiang [Key Laboratory of Materials Modification by Laser, Ion, Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); School of Physics and Optoelectronic Technology, Dalian 116024 (China); Wang, Yong-Xing [College of Electrical Engineering, Dalian 116024 (China); Xia, Guang-Qing [School of Aeronautics and Astronautics, Dalian University of Technology, Dalian 116024 (China)

    2014-07-15

    The atmospheric-pressure microwave N{sub 2}-H{sub 2} plasma torch is generated and diagnosed by optical emission spectroscopy. It is found that a large amount of N atoms and NH radicals are generated in the plasma torch and the emission intensity of N{sub 2}{sup +} first negative band is the strongest over the spectra. The mixture of hydrogen in nitrogen plasma torch causes the morphology of the plasma discharge to change with appearance that the afterglow shrinks greatly and the emission intensity of N{sub 2}{sup +} first negative band decreases with more hydrogen mixed into nitrogen plasma. In atmospheric-pressure microwave-induced plasma torch, the hydrogen imposes a great influence on the characteristics of nitrogen plasma through the quenching effect of the hydrogen on the metastable state of N{sub 2}.

  9. Two-photon absorption laser induced fluorescence measurement of atomic oxygen density in an air atmospheric pressure plasma jet

    Science.gov (United States)

    Conway, Jim; Gogna, Gurusharan; Daniels, Stephen

    2016-09-01

    Two-photon Absorption Laser Induced Fluorescence (TALIF) is used to measure atomic oxygen number density [O] in an air Atmospheric Pressure Plasma Jet (APPJ). A novel technique based on photolysis of O2 is used to calibrate the TALIF system ensuring the same species (O) is probed during calibration and measurement. As a result, laser intensity can be increased outside the TALIF quadratic laser power region without affecting calibration reliability as any high intensity saturation effects will be identical for calibration and experiment. Higher laser intensity gives stronger TALIF signals helping overcome weak TALIF signals often experienced at atmospheric pressure due to collisional quenching. O2 photo-dissociation and two-photon excitation of the resulting [O] are both achieved within the same laser pulse. The photolysis [O] is spatially non-uniform and time varying. To allow valid comparison with [O] in a plasma, spatial and temporal correction factors are required. Knowledge of the laser pulse intensity I0(t), and wavelength allows correction factors to be found using a rate equation model. The air flow into the jet was fixed and the RF power coupled into the system varied. The resulting [O] was found to increase with RF power.

  10. Enhancement of cell growth on honeycomb-structured polylactide surface using atmospheric-pressure plasma jet modification

    Science.gov (United States)

    Cheng, Kuang-Yao; Chang, Chia-Hsing; Yang, Yi-Wei; Liao, Guo-Chun; Liu, Chih-Tung; Wu, Jong-Shinn

    2017-02-01

    In this paper, we compare the cell growth results of NIH-3T3 and Neuro-2A cells over 72 h on flat and honeycomb structured PLA films without and with a two-step atmospheric-pressure nitrogen-based plasma jet treatment. We developed a fabrication system used for forming of a uniform honeycomb structure on PLA surface, which can produce two different pore sizes, 3-4 μm and 7-8 μm, of honeycomb pattern. We applied a previously developed nitrogen-based atmospheric-pressure dielectric barrier discharge (DBD) jet system to treat the PLA film without and with honeycomb structure. NIH-3T3 and a much smaller Neuro-2A cells were cultivated on the films under various surface conditions. The results show that the two-step plasma treatment in combination with a honeycomb structure can enhance cell growth on PLA film, should the cell size be not too smaller than the pore size of honeycomb structure, e.g., NIH-3T3. Otherwise, cell growth would be better on flat PLA film, e.g., Neuro-2A.

  11. Functionalization of graphene by atmospheric pressure plasma jet in air or H{sub 2}O{sub 2} environments

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Weixin [Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556 (United States); Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States); Ptasinska, Sylwia, E-mail: Sylwia.Ptasinska.1@nd.edu [Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556 (United States); Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States)

    2016-03-30

    Graphical abstract: - Highlights: • Facile plasma approach was used to functionalize graphene in air or in H{sub 2}O{sub 2} solution. • For the first time, observation of graphene reduction was observed in oxidative surrounding. • N-doping of graphene in H{sub 2}O{sub 2} solution occurred during the APPJ treatment. • H{sub 2}O{sub 2} solution acted as a buffer layer to prevent graphene etching. • Increase in resistance of the plasma-treated graphene was measured. • The transition of the material property from semi-metallic to semiconducting was revealed in the four-point probe measurement manifested by an increase in sheet resistance of the plasma-treated graphene. - Abstract: The functionalization of graphene, which deforms its band structure, can result in a metal-semiconductor transition. In this work, we report a facile strategy to oxidize single-layer graphene using an atmospheric pressure plasma jet (APPJ) that generates a variety of reactive plasma species at close to ambient temperature. We systematically characterized the oxygen content and chemical structure of the graphene films after plasma treatment under different oxidative conditions (ambient air atmosphere or hydrogen peroxide solution) by X-ray Photoelectron Spectroscopy (XPS). Plasma-treated graphene films containing more than 40% oxygen were obtained in both oxidative environments. Interestingly, prolonged irradiation led to the reduction of graphene oxides. N-doping of graphene also occurred during the APPJ treatment in H{sub 2}O{sub 2} solution; the nitrogen content of the doped graphene was dependent on the duration of irradiation and reached up to 8.1% within 40 min. Moreover, the H{sub 2}O{sub 2} solution served as a buffer layer that prevented damage to the graphene during plasma irradiation. Four-point probe measurement revealed an increase in sheet resistance of the plasma-treated graphene, indicating the transition of the material property from semi-metallic to semiconducting.

  12. Propagation characteristics of atmospheric-pressure He+O{sub 2} plasmas inside a simulated endoscope channel

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.; Chen, Z. Y.; Wang, X. H., E-mail: xhw@mail.xjtu.edu.cn; Li, D.; Yang, A. J.; Liu, D. X.; Rong, M. Z. [State Key Laboratory of Electrical Insulation and Power Equipment, Centre for Plasma Biomedicine, Xi' an Jiaotong University, Xi' an 710049 (China); Chen, H. L. [Frank Reidy Center for Bioelectrics, Old Dominion University, Norfolk, Virginia 23508 (United States); Kong, M. G. [State Key Laboratory of Electrical Insulation and Power Equipment, Centre for Plasma Biomedicine, Xi' an Jiaotong University, Xi' an 710049 (China); Frank Reidy Center for Bioelectrics, Old Dominion University, Norfolk, Virginia 23508 (United States); Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia 23529 (United States)

    2015-11-28

    Cold atmospheric-pressure plasmas have potential to be used for endoscope sterilization. In this study, a long quartz tube was used as the simulated endoscope channel, and an array of electrodes was warped one by one along the tube. Plasmas were generated in the inner channel of the tube, and their propagation characteristics in He+O{sub 2} feedstock gases were studied as a function of the oxygen concentration. It is found that each of the plasmas originates at the edge of an instantaneous cathode, and then it propagates bidirectionally. Interestingly, a plasma head with bright spots is formed in the hollow instantaneous cathode and moves towards its center part, and a plasma tail expands through the electrode gap and then forms a swallow tail in the instantaneous anode. The plasmas are in good axisymmetry when [O{sub 2}] ≤ 0.3%, but not for [O{sub 2}] ≥ 1%, and even behave in a stochastic manner when [O{sub 2}] = 3%. The antibacterial agents are charged species and reactive oxygen species, so their wall fluxes represent the “plasma dosage” for the sterilization. Such fluxes mainly act on the inner wall in the hollow electrode rather than that in the electrode gap, and they get to the maximum efficiency when the oxygen concentration is around 0.3%. It is estimated that one can reduce the electrode gap and enlarge the electrode width to achieve more homogenous and efficient antibacterial effect, which have benefits for sterilization applications.

  13. In vitro efficacy of cold atmospheric pressure plasma on S. sanguinis biofilms in comparison of two test models

    Directory of Open Access Journals (Sweden)

    Gorynia, Susanne

    2013-04-01

    Full Text Available [english] Dental plaque critically affects the etiology of caries, periodontitis and periimplantitis. The mechanical removal of plaque can only be performed partially due to limited accessibility. Therefore, plaque still represents one of the major therapeutic challenges. Even though antiseptic mouth rinses reduce the extent of biofilm temporarily, plaque removal remains incomplete and continuous usage can even result in side effects. Here we tested argon plasma produced by kinpen09 as one option to inactivate microorganisms and to eliminate plaque. biofilms cultivated in either the European Biofilm Reactor (EUREBI or in 24 well plates were treated with argon plasma. In both test systems a homogeneous, good analyzable and stable biofilm was produced on the surface of titan plates within 72 h (>6,9 log CFU/ml. Despite the significantly more powerful biofilm production in EUREBI, the difference of 0.4 log CFU/ml between EUREBI and the 24 well plates was practically not relevant. For that reason both test models were equally qualified for the analysis of efficacy of cold atmospheric pressure plasma. We demonstrate a significant reduction of the biofilm compared to the control in both test models. After plasma application of 180 s the biofilm produced in EUREBI or in 24 well plates was decreased by 0.6 log CFU/ml or 0.5 log CFU/ml, respectively. In comparison to recently published studies analyzing the efficacy of kinpen09, produces a hardly removable biofilm. Future investigations using reduced distances between plasma source and biofilm, various compositions of plasma and alternative plasma sources will contribute to further optimization of the efficacy against biofilms.

  14. Effects of atmospheric-pressure non-thermal bio-compatible plasma and plasma activated nitric oxide water on cervical cancer cells

    Science.gov (United States)

    Li, Ying; Ho Kang, Min; Sup Uhm, Han; Joon Lee, Geon; Ha Choi, Eun; Han, Ihn

    2017-01-01

    Atmospheric-pressure non-thermal bio-compatible plasma is a partially ionized gas with electrically charged particles. Previous studies demonstrated that dielectric barrier discharge (DBD) plasma could induce apoptosis of various cancer cells, in particular demonstrating the selective cytotoxicity of cancer cells over normal cells. Therefore, DBD plasma can be considered as a potential cancer treatment method for clinical applications. We previously developed a microwave jet plasma system, producing nitric oxide called nitric oxide-plasma activated water (NO-PAW). In this study, we explored the effects of NO-PAW on a cervical cancer cell line, in comparison with DBD plasma. The cytotoxicity results showed that the treatment of HeLa cell with DBD for 4 minutes and 7 μM concentration of NO-PAW could reach almost IC60. For the apoptosis assay, 4 minutes treatment of DBD could induce 7% apoptotic effect, whereas 7 μM NO-PAW could induce 18% apoptotic effect. In addition, we assumed that both DBD plasma and NO-PAW could induce HeLa cell apoptosis by facilitating an accumulation of intracellular reactive oxygen and nitrogen species (RONS). Although further detail on the molecular signal pathway is still needed, DBD and NO-PAW could become promising applications for effective and safe clinical trials for cancer therapy. PMID:28361987

  15. Effects of atmospheric-pressure non-thermal bio-compatible plasma and plasma activated nitric oxide water on cervical cancer cells.

    Science.gov (United States)

    Li, Ying; Ho Kang, Min; Sup Uhm, Han; Joon Lee, Geon; Ha Choi, Eun; Han, Ihn

    2017-03-31

    Atmospheric-pressure non-thermal bio-compatible plasma is a partially ionized gas with electrically charged particles. Previous studies demonstrated that dielectric barrier discharge (DBD) plasma could induce apoptosis of various cancer cells, in particular demonstrating the selective cytotoxicity of cancer cells over normal cells. Therefore, DBD plasma can be considered as a potential cancer treatment method for clinical applications. We previously developed a microwave jet plasma system, producing nitric oxide called nitric oxide-plasma activated water (NO-PAW). In this study, we explored the effects of NO-PAW on a cervical cancer cell line, in comparison with DBD plasma. The cytotoxicity results showed that the treatment of HeLa cell with DBD for 4 minutes and 7 μM concentration of NO-PAW could reach almost IC60. For the apoptosis assay, 4 minutes treatment of DBD could induce 7% apoptotic effect, whereas 7 μM NO-PAW could induce 18% apoptotic effect. In addition, we assumed that both DBD plasma and NO-PAW could induce HeLa cell apoptosis by facilitating an accumulation of intracellular reactive oxygen and nitrogen species (RONS). Although further detail on the molecular signal pathway is still needed, DBD and NO-PAW could become promising applications for effective and safe clinical trials for cancer therapy.

  16. Effects of assisted magnetic field to an atmospheric-pressure plasma jet on radical generation at the plasma-surface interface and bactericidal function

    Science.gov (United States)

    Liu, Chih-Tung; Kumakura, Takumi; Ishikawa, Kenji; Hashizume, Hiroshi; Takeda, Keigo; Ito, Masafumi; Hori, Masaru; Wu, Jong-Shinn

    2016-12-01

    A configuration of magnetic-assisted-plasma (MAP) on helium-based atmospheric-pressure plasma jet (APPJ) with an axial magnetic-field of 0.587 T is proposed, which provides good ability for killing bacteria Escherichia coli on the agar surface. Optically, we confirmed that the MAP increased approximately 2.4 times in the electron density estimated by the Stark broadening of H β line emission, and approximately 1.5 times enhancement of atomic oxygen concentration measured by vacuum ultraviolet absorption spectroscopy (VUVAS). Moreover, the generation of hydroxyl radical in the water increased 1.5 times, confirmed by the spin-trapping electron spin-resonance technique. In addition, the bactericidal experiments demonstrated 2.4 times higher for E. coli by the MAP treatment. The MAP configuration is proposed to be highly useful for future bio-medical applications by enhancing the radical generation at the plasma/substrate interface region.

  17. Proliferation assay of mouse embryonic stem (ES) cells exposed to atmospheric-pressure plasmas at room temperature

    Science.gov (United States)

    Miura, Taichi; Ando, Ayumi; Hirano, Kazumi; Ogura, Chika; Kanazawa, Tatsuya; Ikeguchi, Masamichi; Seki, Atsushi; Nishihara, Shoko; Hamaguchi, Satoshi

    2014-11-01

    Proliferation assays of mouse embryonic stem (ES) cells have been performed with cell culture media exposed to atmospheric-pressure plasmas (APPs), which generate reactive species in the media at room temperature. It is found that serum in cell culture media functions as a scavenger of highly reactive species and tends to protect cells in the media against cellular damage. On the other hand, if serum is not present in a cell culture medium when it is exposed to APP, the medium becomes cytotoxic and cannot be detoxified by serum added afterwards. Plasma-induced cytotoxic media hinder proliferation of mouse ES cells and may even cause cell death. It is also shown by nuclear magnetic resonance spectroscopy that organic compounds in cell culture media are in general not significantly modified by plasma exposure. These results indicate that if there is no serum in media when they are exposed to APPs, highly reactive species (such as OH radicals) generated in the media by the APP exposure are immediately converted to less reactive species (such as H2O2), which can no longer readily react with serum that is added to the medium after plasma exposure. This study has clearly shown that it is these less reactive species, rather than highly reactive species, that make the medium cytotoxic to mouse ES cells.

  18. In vitro antimicrobial effects and mechanism of atmospheric-pressure He/O2 plasma jet on Staphylococcus aureus biofilm

    Science.gov (United States)

    Xu, Zimu; Shen, Jie; Cheng, Cheng; Hu, Shuheng; Lan, Yan; Chu, Paul K.

    2017-03-01

    The antimicrobial effects and associated mechanism of inactivation of Staphylococcus aureus (S. aureus) NCTC-8325 biofilms induced by a He/O2 atmospheric-pressure plasma jet (APPJ) are investigated in vitro. According to CFU (colony forming units) counting and the resazurin-based assay, the 10 min He/O2 (0.5%) APPJ treatment produces the optimal inactivation efficacy (>5 log10 ml‑1) against the S. aureus biofilm and 5% of the bacteria enter a viable but non-culturable (VBNC) state. Meanwhile, 94% of the bacteria suffer from membrane damage according to SYTO 9/PI counterstaining. Scanning electron microscopy (SEM) reveals that plasma exposure erodes the extracellular polymeric substances (EPS) and then the cellular structure. The H2DCFDA-stained biofilms show larger concentrations of intracellular reactive oxygen species (ROS) in membrane-intact bacteria with increasing plasma dose. The admixture of oxygen in the working gas highly contributes to the deactivation efficacy of the APPJ against S. aureus and the plasma-induced endogenous ROS may work together with the discharge-generated ROS to continuously damage the bacterial membrane structure leading to deactivation of the biofilm microbes.

  19. Spatial distribution of the electrical potential and ion concentration in the downstream area of atmospheric pressure remote plasma

    Directory of Open Access Journals (Sweden)

    M. V. Mishin

    2014-10-01

    Full Text Available This paper presents the results from an experimental study of the ion flux characteristics behind the remote plasma zone in a vertical tube reaction chamber for atmospheric pressure plasma enhanced chemical vapor deposition. Capacitively coupled radio frequency plasma was generated in pure He and gas mixtures: He–Ar, He–O2, He–TEOS. We previously used the reaction system He–TEOS for the synthesis of self-assembled structures of silicon dioxide nanoparticles. It is likely that the electrical parameters of the area, where nanoparticles have been transported from the synthesis zone to the substrate, play a significant role in the self-organization processes both in the vapor phase and on the substrate surface. The results from the spatial distribution of the electrical potential and ion concentration in the discharge downstream area measured by means of the external probe of original design and the special data processing method are demonstrated in this work. Positive and negatives ions with maximum concentrations of 106–107 cm−3 have been found at 10–80 mm distance behind the plasma zone. On the basis of the revealed distributions for different gas mixtures, the physical model of the observed phenomena is proposed. The model illustrates the capability of the virtual ion emitter formation behind the discharge gap and the presence of an extremum of the electrical potential at the distance of approximately 10−2–10−1 mm from the grounded electrode.

  20. Evaluation of Penicillium digitatum sterilization using non-equilibrium atmospheric pressure plasma by terahertz time-domain spectroscopy

    Science.gov (United States)

    Hiraoka, Takehiro; Ebizuka, Noboru; Takeda, Keigo; Ohta, Takayuki; Kondo, Hiroki; Ishikawa, Kenji; Kawase, Kodo; Ito, Masafumi; Sekine, Makoto; Hori, Masaru

    2011-10-01

    Recently, the plasma sterilization has attracted much attention as a new sterilization technique that takes the place of spraying agricultural chemicals. The conventional methods for sterilization evaluation, was demanded to culture the samples for several days after plasma treatment. Then, we focused on Terahertz time-domain spectroscopy (THz-TDS). At the THz region, vibrational modes of biological molecules and fingerprint spectra of biologically-relevant molecules were also observed. In this study, our purpose was measurement of the fingerprint spectrum of the Penicillium digitatum (PD) spore and establishment of sterilization method by THz-TDS. The sample was 40mg/ml PD spore suspensions which dropped on cover glass. The atmospheric pressure plasma generated under the conditions which Ar gas flow was 3slm, and alternating voltage of 6kV was applied. The samples were exposed the plasma from 10mm distance for 10 minutes. We could obtain the fingerprint spectrum of the PD spore from 0.5 to 0.9THz. This result indicated the possibility of in-situ evaluation for PD sterilization using THz-TDS.

  1. Optical and Structural Properties of ZnO Nanoparticles Synthesized by CO2 Microwave Plasma at Atmospheric Pressure

    Directory of Open Access Journals (Sweden)

    Se Min Chun

    2014-01-01

    Full Text Available The results of carbon-doped zinc oxide nanoparticles synthesized by CO2 microwave plasma at atmospheric pressure are presented. The 2.45-GHz microwave plasma torch and feeder for injecting Zn granules are used in the synthesis of zinc oxide nanoparticles. The Zn granules (13.5 g/min were introduced into the microwave plasma by CO2 (5 l/min swirl gas. The microwave power delivered to the CO2 microwave plasma was 1 kW. The synthesis of carbon-doped zinc oxide nanoparticles was carried out in accordance with CO2 + Zn → carbon-doped ZnO + CO. The synthesized carbon-doped zinc oxide nanoparticles have a high purity hexagonal phase. The absorption edge of carbon-doped zinc oxide nanoparticles exhibited a red shift from a high-energy wavelength to lower in the UV-visible spectrum, due to band gap narrowing. A UV-NIR spectrometer, X-ray diffraction, emission scanning electron-microscopy, energy dispersive X-ray microanalysis, Fourier transform infrared spectroscopy, and a UV-Vis-NIR spectrophotometer were used for the characterization of the as-produced products.

  2. Partial hydrophilic modification of biaxially oriented polypropylene film by an atmospheric pressure plasma jet with the allylamine monomer

    Science.gov (United States)

    Chen, W. X.; Yu, J. S.; Hu, W.; Chen, G. L.

    2016-11-01

    In this paper, the partial modification of the biaxially oriented polypropylene (BOPP) film for potential biological and packaging applications was achieved via hydrophilic modification using atmospheric pressure plasma jet (APPJ). In the APPJ system, the allylamine (ALA) monomer was polymerized on the BOPP surface by either the Ar/O2 or the He/O2 plasma. The results showed that plasmatic modification created many micro/nano sized holes on the BOPP film, which increased the surface roughness dramatically and the increased roughness enhanced the combining intensity between the BOPP film and the ALA polymer. However, such a plasmatic modification increased the water vapor permeability. The FTIR and XPS characterizations showed that the amine groups were grafted onto the BOPP film, and the contact angle of the BOPP film decreases from 98.5° to 8°. Compared with the BOPP films treated by the Ar or He plasma, the barrier property of the modified BOPP film increased significantly when the ALA polymer was incorporated. The bio-affinity/toxicity of ALA polymer was illustrated by the attachment of the cultured SMMC-7721 hepatoma cells on the modified BOPP film. The significant enhancement in the cell density indicated that modified BOPP film was highly bio-compatible and non-toxic, especially treated with the Ar/O2/ALA plasma.

  3. Modification of glassy carbon surfaces by atmospheric pressure cold plasma torch

    DEFF Research Database (Denmark)

    Mortensen, Henrik Junge; Kusano, Yukihiro; Leipold, Frank

    2006-01-01

    The effect of plasma treatment on glassy carbon (GC) surfaces was studied with adhesion improvement in mind. A newly constructed remote plasma source was used to treat GC plates. Pure He and a dilute NH3/He mixture were used as feed gases. Optical emission spectroscopy was performed for plasma to...

  4. Atmospheric-pressure plasma jet induces apoptosis involving mitochondria via generation of free radicals.

    Directory of Open Access Journals (Sweden)

    Hak Jun Ahn

    Full Text Available The plasma jet has been proposed as a novel therapeutic method for anticancer treatment. However, its biological effects and mechanism of action remain elusive. Here, we investigated its cell death effects and underlying molecular mechanisms, using air and N₂ plasma jets from a micro nozzle array. Treatment with air or N₂ plasma jets caused apoptotic death in human cervical cancer HeLa cells, simultaneously with depolarization of mitochondrial membrane potential. In addition, the plasma jets were able to generate reactive oxygen species (ROS, which function as surrogate apoptotic signals by targeting the mitochondrial membrane potential. Antioxidants or caspase inhibitors ameliorated the apoptotic cell death induced by the air and N₂ plasma jets, suggesting that the plasma jet may generate ROS as a proapoptotic cue, thus initiating mitochondria-mediated apoptosis. Taken together, our data suggest the potential employment of plasma jets as a novel therapy for cancer.

  5. Atmospheric-pressure plasma jet induces apoptosis involving mitochondria via generation of free radicals.

    Science.gov (United States)

    Ahn, Hak Jun; Kim, Kang Il; Kim, Geunyoung; Moon, Eunpyo; Yang, Sang Sik; Lee, Jong-Soo

    2011-01-01

    The plasma jet has been proposed as a novel therapeutic method for anticancer treatment. However, its biological effects and mechanism of action remain elusive. Here, we investigated its cell death effects and underlying molecular mechanisms, using air and N₂ plasma jets from a micro nozzle array. Treatment with air or N₂ plasma jets caused apoptotic death in human cervical cancer HeLa cells, simultaneously with depolarization of mitochondrial membrane potential. In addition, the plasma jets were able to generate reactive oxygen species (ROS), which function as surrogate apoptotic signals by targeting the mitochondrial membrane potential. Antioxidants or caspase inhibitors ameliorated the apoptotic cell death induced by the air and N₂ plasma jets, suggesting that the plasma jet may generate ROS as a proapoptotic cue, thus initiating mitochondria-mediated apoptosis. Taken together, our data suggest the potential employment of plasma jets as a novel therapy for cancer.

  6. Atmospheric Plasma Depainting

    Science.gov (United States)

    2014-11-19

    Plasma Carbon Dioxide Water Vapor 11 Atmospheric Plasma Depainting, ASETSDefense, Nov 19, 2014 Features and Benefits of APCR Technology Feature...Depainting, ASETSDefense, Nov 19, 2014 14 APC on Aluminum Removal to Primer RAM on Carbon Fiber Partial Topcoat Removal APC Topcoat RAM...60Hz Plasma Flux™ Power Supply VENT To Facility HEPA <= Filtration COTS Six-Axis Robot Aircraft part Particulate Collection System

  7. Cold atmospheric pressure plasma treatment of ready-to-eat meat: inactivation of Listeria innocua and changes in product quality.

    Science.gov (United States)

    Rød, Sara Katrine; Hansen, Flemming; Leipold, Frank; Knøchel, Susanne

    2012-05-01

    The application of cold atmospheric pressure plasma for decontamination of a sliced ready-to-eat (RTE) meat product (bresaola) inoculated with Listeria innocua was investigated. Inoculated samples were treated at 15.5, 31, and 62 W for 2-60 s inside sealed linear-low-density-polyethylene bags containing 30% oxygen and 70% argon. Treatments resulted in a reduction of L. innocua ranging from 0.8 ± 0.4 to 1.6 ± 0.5 log cfu/g with no significant effects of time and intensity while multiple treatments at 15.5 and 62 W of 20 s with a 10 min interval increased reduction of L. innocua with increasing number of treatments. Concentrations of thiobarbituric acid reactive substances (TBARS) increased with power, treatments and storage time and were significantly higher than those of control samples after 1 and 14 days of storage at 5 °C. However, the levels were low (from 0.1 to 0.4 mg/kg) and beneath the sensory threshold level. Surface colour changes included loss of redness of ∼40% and 70% after 1 and 14 days of storage, respectively, regardless of plasma treatment. The results indicate that plasma may be applicable in surface decontamination of pre-packed RTE food products. However, oxidation may constitute an issue in some products.

  8. Preliminary study on atmospheric-pressure plasma-based chemical dry figuring and finishing of reaction-sintered silicon carbide

    Science.gov (United States)

    Shen, Xinmin; Deng, Hui; Zhang, Xiaonan; Peng, Kang; Yamamura, Kazuya

    2016-10-01

    Reaction-sintered silicon carbide (RS-SiC) is a research focus in the field of optical manufacturing. Atmospheric-pressure plasma-based chemical dry figuring and finishing, which consist of plasma chemical vaporization machining (PCVM) and plasma-assisted polishing (PAP), were applied to improve material removal rate (MRR) in rapid figuring and ameliorate surface quality in fine finishing. Through observing the processed RS-SiC sample in PCVM by scanning white-light interferometer (SWLI), the calculated peak-MRR and volume-MRR were 0.533 μm/min and 2.78×10-3 mm3/min, respectively. The comparisons of surface roughness and morphology of the RS-SiC samples before and after PCVM were obtained by the scanning electron microscope and atomic force microscope. It could be found that the processed RS-SiC surface was deteriorated with surface roughness rms 382.116 nm. The evaluations of surface quality of the processed RS-SiC sample in PAP corresponding to different collocations of autorotation speed and revolution speed were obtained by SWLI measurement. The optimal surface roughness rms of the processed RS-SiC sample in PAP was 2.186 nm. There were no subsurface damages, scratches, or residual stresses on the processed sample in PAP. The results indicate that parameters in PAP should be strictly selected, and the optimal parameters can simultaneously obtain high MRR and smooth surface.

  9. A Revival of Waste: Atmospheric Pressure Nitrogen Plasma Jet Enhanced Jumbo Silicon/Silicon Carbide Composite in Lithium Ion Batteries.

    Science.gov (United States)

    Chen, Bing-Hong; Chuang, Shang-I; Liu, Wei-Ren; Duh, Jenq-Gong

    2015-12-30

    In this study, a jumbo silicon/silicon carbide (Si/SiC) composite (JSC), a novel anode material source, was extracted from solar power industry cutting waste and used as a material for lithium-ion batteries (LIBs), instead of manufacturing the nanolized-Si. Unlike previous methods used for preventing volume expansion and solid electrolyte interphase (SEI), the approach proposed here simply entails applying surface modification to JSC-based electrodes by using nitrogen-atmospheric pressure plasma jet (N-APPJ) treatment process. Surface organic bonds were rearranged and N-doped compounds were formed on the electrodes through applying different plasma treatment durations, and the qualitative examinations of before/after plasma treatment were identified by X-ray photoelectron spectroscopy (XPS) and electron probe microanalyzer (EPMA). The surface modification resulted in the enhancement of electrochemical performance with stable capacity retention and high Coulombic efficiency. In addition, depth profile and scanning electron microscope (SEM) images were executed to determine the existence of Li-N matrix and how the nitrogen compounds change the surface conditions of the electrodes. The N-APPJ-induced rapid surface modification is a major breakthrough for processing recycled waste that can serve as anode materials for next-generation high-performance LIBs.

  10. Diagnosis of Methane Plasma Generated in an Atmospheric Pressure DBD Micro-Jet by Optical Emission Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun-Feng; BIAN Xin-Chao; CHEN Qiang; LIU Fu-Ping; LIU Zhong-Wei

    2009-01-01

    Diagnosis of methane plasma,generated in an atmospheric pressure dielectric barrier discharge (DBD) microplasma jet with a quartz tube as dielectric material by a 25 kHz sinusoidal ac power source,is conducted by optical emission spectroscopy (OES).The reactive radicals in methane plasma such as CH,C2,and Ha are detected insitu by OES.The possible dissociation mechanism of methane in diluted Ar plasma is deduced from spectra.In addition,the density of CH radical,which is considered as one of the precursors in diamond-like (DLC) film formation,affected by the parameters of input voltage and the feed gas flow rate,is emphasized. With the Boltzmann plots,four Ar atomic spectral lines (located at 675.28nm,687.13nm,738.40nm and 794.82nm,respectively) are chosen to calculate the electron temperature,and the dependence of electron temperature on discharge parameters is also investigated.

  11. Atmospheric pressure plasma processing of polymeric materials utilizing close proximity indirect exposure

    Energy Technology Data Exchange (ETDEWEB)

    Paulauskas, Felix L.; Bonds, Truman

    2016-09-20

    A plasma treatment method that includes providing treatment chamber including an intermediate heating volume and an interior treatment volume. The interior treatment volume contains an electrode assembly for generating a plasma and the intermediate heating volume heats the interior treatment volume. A work piece is traversed through the treatment chamber. A process gas is introduced to the interior treatment volume of the treatment chamber. A plasma is formed with the electrode assembly from the process gas, wherein a reactive species of the plasma is accelerated towards the fiber tow by flow vortices produced in the interior treatment volume by the electrode assembly.

  12. Electron properties and air mixing in radio frequency driven argon plasma jets at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Gessel, Bram van; Bruggeman, Peter [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands); Brandenburg, Ronny [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands); Leibniz Institute for Plasma Science and Technology (INP Greifswald), Felix-Hausdorff-Str. 2, D-17489 Greifswald (Germany)

    2013-08-05

    A time modulated radio frequency (RF) plasma jet operated with an Ar mixture is investigated by measuring the electron density and electron temperature using Thomson scattering. The measurements have been performed spatially resolved for two different electrode configurations and as a function of the plasma dissipated power and air concentration admixed to the Ar. Time resolved measurements of electron densities and temperatures during the RF cycle and after plasma power switch-off are presented. Furthermore, the influence of the plasma on the air entrainment into the effluent is studied using Raman scattering.

  13. The use of atmospheric pressure plasma-treated water as a source of nitrite for emulsion-type sausage.

    Science.gov (United States)

    Jung, Samooel; Kim, Hyun Joo; Park, Sanghoo; In Yong, Hae; Choe, Jun Ho; Jeon, Hee-Joon; Choe, Wonho; Jo, Cheorun

    2015-10-01

    We investigated the possible use of atmospheric pressure plasma-treated water (PTW) as a nitrite source in curing process. Emulsion-type sausages were manufactured with PTW, celery powder containing nitrite, and synthetic sodium nitrite at a concentration of nitrite ion 70mgkg(-1). In terms of sausage quality, there were no noticeable effects of PTW on the total aerobic bacterial counts, color, and peroxide values of sausages compared with those of celery powder and sodium nitrite throughout 28days of storage at 4°C. Sausage with added PTW had lower concentrations of residual nitrite compared to those of added celery powder and sodium nitrite during the storage period (Psausages were not different, whereas the sausage with added celery powder received the lowest scores in taste and acceptability. From the results, it is concluded that PTW can be used as a nitrite source equivalent to a natural curing agent.

  14. Experimental study of propagation characteristics of a pulse-modulated surface-wave argon plasma at atmospheric pressure

    Science.gov (United States)

    Chen, Chuan-Jie; Li, Shou-Zhe; Wu, Yue; Li, Zhen-Ye; Zhang, Jialiang; Wang, Yong-Xing

    2016-12-01

    An atmospheric-pressure, pulse-modulated surface wave argon plasma is investigated with respect to its propagation of the ionization front. The time-resolved photographs about the advance of the ionization front are taken using a high speed camera. The ionization front velocity and its rise time when propagating along the discharge tube are measured with respect to a series of values of input power, duty ratio, and the pulse repetition frequency. The interpretations are given on the basis of the ionization and diffusion processes. And it is also found that the reduced electric field and memory effect from previous discharge impose the influence on both the ionization front velocity and its rise time strongly.

  15. Characteristic effects onto C13H12N2O3 molecule dissolved in solvents of argon plasma at atmospheric pressure

    Science.gov (United States)

    Tanışlı, Murat; Taşal, Erol

    2017-02-01

    We could easily argue that the decomposition of the chemical chain molecules is a compelling application when it comes to the atmospheric pressure plasma. In this paper, we have investigated the effect of the atmospheric pressure argon plasma on 4-((2-methoxyphenyl)diazenyl)benzene-1,3,-diol molecule (abbreviated as 4MBD) at room temperature. 4MBD molecule is one of the industrial dye molecules used widely. When considering the ecological life, this molecule is very harmful and dangerous. As such, we suggest a new decomposing method for such molecules. Atmospheric pressure plasma jet is principally treated for the breakdown of the molecule in question. Fourier transform infrared spectrometry and UV-Vis spectrophotometry tools are used to characterization of the molecules subsequent to the plasma applications to 4MBD molecule in ethanol and methanol solvents. The atmospheric-pressure plasma jet of argon (Ar) as non-equilibrium has been formed by ac-power generator with frequency—24 kHz and voltage—12 kV. Characterizations for solutions prepared with ethanol and methanol solvents of 4MBD molecule have been examined after applying (duration 3 min) the atmospheric pressure plasma jet. The molecule is broken at 6C-7N-8N=9C stretching peak in consequence of the plasma treatment. The new plasma photo-products for ethanol and methanol solutions are produced as 6C-7N-8N=9C (strong, varying) and 12C=17O (strong, wide) stretching peaks. Also, the bathochromic drifts are discerned.

  16. The evaluation of surface and adhesive bonding properties for cold rolled steel sheet for automotive treated by Ar/O{sub 2} atmospheric pressure plasma

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chan Joo; Lee, Sang Kon; Kim Byung Min [Pusan National University, Busan (Korea, Republic of); Park, Keun Whan [Sungwoo Hitech Technical Institute, Busan (Korea, Republic of)

    2008-04-15

    Cold rolled steel sheet for automotive was treated by Ar/O{sub 2} atmospheric pressure plasma to improve the adhesive bonding strength. Through the contact angle test and calculation of surface free energy for cold rolled steel sheet, the changes of surface properties were investigated before and after plasma treatment. The contact angle was decreased and surface free energy was increased after plasma treatment. And the change of surface roughness and morphology were observed by AFM(Atomic Force Microscope). The surface roughness of steel sheet was slightly changed. Based on Taguchi method, single lap shear test was performed to investigate the effect of experimental parameter such as plasma power, treatment time and flow rate of O{sub 2} gas. Results shows that the bonding strength of steel sheet treated in Ar/O{sub 2} atmospheric pressure plasma was improved about 20% compared with untreated sheet.

  17. DC-driven plasma gun: self-oscillatory operation mode of atmospheric-pressure helium plasma jet comprised of repetitive streamer breakdowns

    Science.gov (United States)

    Wang, Xingxing; Shashurin, Alexey

    2017-02-01

    This paper presents and studies helium atmospheric pressure plasma jet comprised of a series of repetitive streamer breakdowns, which is driven by pure DC high voltage (self-oscillatory behavior). The repetition frequency of the breakdowns is governed by the geometry of discharge electrodes/surroundings and gas flow rate. Each next streamer is initiated when the electric field on the anode tip recovers after the previous breakdown and reaches the breakdown threshold value of about 2.5 kV cm-1. One type of the helium plasma gun designed using this operational principle is demonstrated. The gun operates on about 3 kV DC high voltage and is comprised of the series of the repetitive streamer breakdowns at a frequency of about 13 kHz.

  18. Targeting cancer cells with reactive oxygen and nitrogen species generated by atmospheric-pressure air plasma.

    Directory of Open Access Journals (Sweden)

    Hak Jun Ahn

    Full Text Available The plasma jet has been proposed as a novel therapeutic method for cancer. Anticancer activity of plasma has been reported to involve mitochondrial dysfunction. However, what constituents generated by plasma is linked to this anticancer process and its mechanism of action remain unclear. Here, we report that the therapeutic effects of air plasma result from generation of reactive oxygen/nitrogen species (ROS/RNS including H2O2, Ox, OH-, •O2, NOx, leading to depolarization of mitochondrial membrane potential and mitochondrial ROS accumulation. Simultaneously, ROS/RNS activate c-Jun NH2-terminal kinase (JNK and p38 kinase. As a consequence, treatment with air plasma jets induces apoptotic death in human cervical cancer HeLa cells. Pretreatment of the cells with antioxidants, JNK and p38 inhibitors, or JNK and p38 siRNA abrogates the depolarization of mitochondrial membrane potential and impairs the air plasma-induced apoptotic cell death, suggesting that the ROS/RNS generated by plasma trigger signaling pathways involving JNK and p38 and promote mitochondrial perturbation, leading to apoptosis. Therefore, administration of air plasma may be a feasible strategy to eliminate cancer cells.

  19. Novel thin films deposited on electrospun PCL scaffolds by atmospheric pressure plasma jet for L929 fibroblast cell cultivation

    Science.gov (United States)

    Gozutok, M.; Baitukha, A.; Arefi-Khonsari, F.; Turkoglu Sasmazel, H.

    2016-11-01

    This paper reports on the deposition of PCL homopolymers and poly ɛ-caprolactone-polyethylene glycol (PCL-PEG) copolymers by atmospheric pressure plasma jet (APPJ) onto electrospun PCL scaffolds for improving L929 fibroblast cell growth. Polymer deposited scaffolds showed better stability as well as lower CA as compared to those treated with APPJ in Ar alone used as the carrier gas to introduce the precursors due to the formation of polar groups generated during the plasma treatment, such as -OH and/or -COO. Average fiber and porosity sizes were calculated by using SEM photographs and the ImageJ Launcher Software program and higher values were observed for both PCL and PCL-PEG deposited scaffolds than the untreated electrospun PCL scaffolds. XPS analysis showed that C1s% content decreased for PCL deposited (from 82.4% to 71.0%) and PCL-PEG deposited (from 82.4% to 57.7%) and O1s% composition increased for PCL deposited (from 17.6% to 29.0%) and PCL-PEG deposited (from 17.6% to 42.3%) compared to the untreated one. XPS results proved more incorporation of oxygen moieties on the deposited surfaces than the untreated samples giving rise to more hydrophilic surfaces to the deposited ones. Standard in vitro MTT test, Giemsa staining, fluorescence and CLSM imaging techniques were used for the determination of cell viability, adhesion and proliferation. Cell culture experiments showed that PCL-PEG deposited electrospun PCL scaffolds had the most promising cell adhesion, proliferation and growth among the treated scaffolds. The increased average fiber diameter caused by deposition as well as oxygen containing polar groups formed on the surfaces due to the radicals present in the plasma atmosphere provided higher surface area and functionality, respectively, for cells to attach, yielding better biocompatibility performance.

  20. Method for atmospheric pressure reactive atom plasma processing for surface modification

    Science.gov (United States)

    Carr, Jeffrey W.

    2009-09-22

    Reactive atom plasma processing can be used to shape, polish, planarize and clean the surfaces of difficult materials with minimal subsurface damage. The apparatus and methods use a plasma torch, such as a conventional ICP torch. The workpiece and plasma torch are moved with respect to each other, whether by translating and/or rotating the workpiece, the plasma, or both. The plasma discharge from the torch can be used to shape, planarize, polish, and/or clean the surface of the workpiece, as well as to thin the workpiece. The processing may cause minimal or no damage to the workpiece underneath the surface, and may involve removing material from the surface of the workpiece.

  1. Mechanism and comparison of needle-type non-thermal direct and indirect atmospheric pressure plasma jets on the degradation of dyes

    OpenAIRE

    Pankaj Attri; Maksudbek Yusupov; Ji Hoon Park; Lakshmi Prasanna Lingamdinne; Janardhan Reddy Koduru; Masaharu Shiratani; Eun Ha Choi; Annemie Bogaerts

    2016-01-01

    Purified water supply for human use, agriculture and industry is the major global priority nowadays. The advanced oxidation process based on atmospheric pressure non-thermal plasma (NTP) has been used for purification of wastewater, although the underlying mechanisms of degradation of organic pollutants are still unknown. In this study we employ two needle-type atmospheric pressure non-thermal plasma jets, i.e., indirect (ID-APPJ) and direct (D-APPJ) jets operating at Ar feed gas, for the tre...

  2. Control of ROS and RNS productions in liquid in atmospheric pressure plasma-jet system

    Science.gov (United States)

    Uchida, Giichiro; Ito, Taiki; Takenaka, Kosuke; Ikeda, Junichiro; Setsuhara, Yuichi

    2016-09-01

    Non-thermal plasma jets are of current interest in biomedical applications such as wound disinfection and even treatment of cancer tumors. Beneficial therapeutic effects in medical applications are attributed to excited species of oxygen and nitrogen from air. However, to control the production of these species in the plasma jet is difficult because their production is strongly dependent on concentration of nitrogen and oxygen from ambient air into the plasma jet. In this study, we analyze the discharge characteristics and the ROS and RNS productions in liquid in low- and high-frequency plasma-jet systems. Our experiments demonstrated the marked effects of surrounding gas near the plasma jet on ROS and RNS productions in liquid. By controlling the surround gas, the O2 and N2 main plasma jets are selectively produced even in open air. We also show that the concentration ratio of NO2- to H2O2 in liquid is precisely tuned from 0 to 0.18 in deionized water by changing N2 gas ratio (N2 / (N2 +O2)) in the main discharge gas, where high NO2- ratio is obtained at N2 gas ratio at N2 / (N2 +O2) = 0 . 8 . The low-frequency plasma jet with controlled surrounding gas is an effective plasma source for ROS and RNS productions in liquid, and can be a useful tool for biomedical applications. This study was partly supported by a Grant-in-Aid for Scientific Research on Innovative Areas ``Plasma Medical Innovation'' (24108003) from the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT).

  3. Identification of the biologically active liquid chemistry induced by a nonthermal atmospheric pressure plasma jet.

    Science.gov (United States)

    Wende, Kristian; Williams, Paul; Dalluge, Joe; Gaens, Wouter Van; Aboubakr, Hamada; Bischof, John; von Woedtke, Thomas; Goyal, Sagar M; Weltmann, Klaus-Dieter; Bogaerts, Annemie; Masur, Kai; Bruggeman, Peter J

    2015-06-06

    The mechanism of interaction of cold nonequilibrium plasma jets with mammalian cells in physiologic liquid is reported. The major biological active species produced by an argon RF plasma jet responsible for cell viability reduction are analyzed by experimental results obtained through physical, biological, and chemical diagnostics. This is complemented with chemical kinetics modeling of the plasma source to assess the dominant reactive gas phase species. Different plasma chemistries are obtained by changing the feed gas composition of the cold argon based RF plasma jet from argon, humidified argon (0.27%), to argon/oxygen (1%) and argon/air (1%) at constant power. A minimal consensus physiologic liquid was used, providing isotonic and isohydric conditions and nutrients but is devoid of scavengers or serum constituents. While argon and humidified argon plasma led to the creation of hydrogen peroxide dominated action on the mammalian cells, argon-oxygen and argon-air plasma created a very different biological action and was characterized by trace amounts of hydrogen peroxide only. In particular, for the argon-oxygen (1%), the authors observed a strong negative effect on mammalian cell proliferation and metabolism. This effect was distance dependent and showed a half life time of 30 min in a scavenger free physiologic buffer. Neither catalase and mannitol nor superoxide dismutase could rescue the cell proliferation rate. The strong distance dependency of the effect as well as the low water solubility rules out a major role for ozone and singlet oxygen but suggests a dominant role of atomic oxygen. Experimental results suggest that O reacts with chloride, yielding Cl2(-) or ClO(-). These chlorine species have a limited lifetime under physiologic conditions and therefore show a strong time dependent biological activity. The outcomes are compared with an argon MHz plasma jet (kinpen) to assess the differences between these (at least seemingly) similar plasma sources.

  4. Estimation of dynamic properties of attractors observed in hollow copper electrode atmospheric pressure arc plasma system

    Indian Academy of Sciences (India)

    S Ghorul; S N Sahasrabudhe; P S S Murthy; A K Das; N Venkatramani

    2002-07-01

    Understanding of the basic nature of arc root fluctuation is still one of the unsolved problems in thermal arc plasma physics. It has direct impact on myriads of thermal plasma applications being implemented at present. Recently, chaotic nature of arc root behavior has been reported through the analysis of voltages, acoustic and optical signals which are generated from a hollow copper electrode arc plasma torch. In this paper we present details of computations involved in the estimation process of various dynamic properties and show how they reflect chaotic behavior of arc root in the system.

  5. In-package atmospheric pressure cold plasma treatment of cherry tomatoes.

    Science.gov (United States)

    Misra, Nrusimha Nath; Keener, Kevin M; Bourke, Paula; Mosnier, Jean-Paul; Cullen, Patrick J

    2014-08-01

    Cold plasma is increasingly under research for decontamination of foods, especially fresh fruits and vegetables. The effect of cold plasma on food quality, however, remains under researched. This study investigates the effects of cold plasma generated within a sealed package from a dielectric barrier discharge on the physical quality parameters and respiration rates of cherry tomatoes. Respiration rates and weight loss were monitored continuously, while other parameters are reported at the end of storage period. Differences among weight loss, pH and firmness for control and treated cherry tomatoes were insignificant towards the end of storage life. Changes in respiration rates and colour of tomatoes were recorded as a function of treatment, which were not drastic. The results implicate that cold plasma could be employed as a means for decontamination of cherry tomatoes while retaining product quality.

  6. Amorphous carbon film deposition on inner surface of tubes using atmospheric pressure pulsed filamentary plasma source

    CERN Document Server

    Pothiraja, Ramasamy; Awakowicz, Peter

    2011-01-01

    Uniform amorphous carbon film is deposited on the inner surface of quartz tube having the inner diameter of 6 mm and the outer diameter of 8 mm. A pulsed filamentary plasma source is used for the deposition. Long plasma filaments (~ 140 mm) as a positive discharge are generated inside the tube in argon with methane admixture. FTIR-ATR, XRD, SEM, LSM and XPS analyses give the conclusion that deposited film is amorphous composed of non-hydrogenated sp2 carbon and hydrogenated sp3 carbon. Plasma is characterized using optical emission spectroscopy, voltage-current measurement, microphotography and numerical simulation. On the basis of observed plasma parameters, the kinetics of the film deposition process is discussed.

  7. Spatially resolved spectroscopy of an atmospheric pressure microwave plasma jet used for surface treatment

    OpenAIRE

    Potočňáková Lucia; Hnilica Jaroslav; Kudrle Vít

    2014-01-01

    In this study, the variations of properties of a microwave plasma jet (surfatron) along the discharge axis have been investigated using optical emission spectroscopy. As the argon jet is not enclosed, the spatial distribution of individual species in effluent plasma is the result of rather complicated interplay between energy loss and gradual mixing with the air. Spatial 2D relative intensity profiles of atomic lines and molecular bands at 310 nm, 336 nm, 391 nm and 656 nm are presented in th...

  8. Analysis of Ar plasma jets induced by single and double dielectric barrier discharges at atmospheric pressure

    Science.gov (United States)

    Judée, F.; Merbahi, N.; Wattieaux, G.; Yousfi, M.

    2016-09-01

    The aim is the comparison of different plasma parameters of single and double dielectric barrier discharge plasma jet configurations (S-DBD and D-DBD) which are potentially usable in biomedical applications. Both configurations are studied in terms of electric field distribution, electrical discharge characteristics, plasma parameters (estimated by optical emission spectroscopy analysis), and hydrodynamics of the plasma jet for electrical parameters of power supplies corresponding to an applied voltage of 10 kV, pulse duration of 1 μs, frequency of 9.69 kHz, and Ar flow of 2 l/min. We observed that the D-DBD configuration requires half the electrical power one needs to provide in the S-DBD case to generate a plasma jet with similar characteristics: excitation temperature around 4700 K, electron density around 2.5 × 1014 cm-3, gas temperature of about 320 K, a relatively high atomic oxygen concentration reaching up to 1000 ppm, the presence of reactive oxygen and nitrogen species (nitric oxide, hydroxyl radical, and atomic oxygen), and an irradiance in the UV-C range of about 20 μW cm-2. Moreover, it has been observed that D-DBD plasma jet is more sensitive to short pulse durations, probably due to the charge accumulation over the dielectric barrier around the internal electrode. This results in a significantly longer plasma length in the D-DBD configuration than in the S-DBD one up to a critical flow rate (2.25 l/min) before the occurrence of turbulence in the D-DBD case. Conversely, ionization wave velocities are significantly higher in the S-DBD setup (3.35 × 105 m/s against 1.02 × 105 m/s for D-DBD), probably due to the higher electrostatic field close to the high voltage electrode in the S-DBD plasma jet.

  9. Reforming of biogas to synthesis gas by a rotating arc plasma at atmospheric pressure

    Science.gov (United States)

    Chung, Woo-Jae; Park, Hyun-Woo; Liu, Jing-Lin; Park, Dong-Wha

    2015-09-01

    In order to produce synthesis gas, reforming of biogas composed with 60 percent for CH4 and 40 percent for CO2 was performed by a novel rotating arc plasma process. The effect of O2/CH4 ratio on the conversion, syngas composition and energy cost was investigated to evaluate the performance of proposed system compared with conventional gliding arc plasma process. When the O2/CH4 ratio was increased from 0.4 to 0.9, the conversions of CH4 and O2 increased up to 97.5 percent and 98.8 percent, respectively, while CO2 conversion was almost constant to be 38.6 percent. This is due to more enhance the partial oxidation of CH4 to CO and H2 than that of dry reforming by increasing the O2/CH4 ratio. In this work, energy cost of 32 kJ/mol was achieved with high syngas composition of 71 percent using pure O2 as oxidant reactant. These are lower than those of different arc plasma processes (energy cost of 122 - 1870 kJ/mol) such as spark, spark-shade and gliding arc plasma. Because, this rotating arc plasma can remain in a long arc length and a large volume of plasma with constant arc length mode.

  10. Methods of gas purification and effect on the ion composition in an RF atmospheric pressure plasma jet investigated by mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Grosse-Kreul, Simon; Huebner, Simon; Schneider, Simon; Keudell, Achim von; Benedikt, Jan [Ruhr-Universitaet Bochum, Institute for Experimental Physics II, Bochum (Germany)

    2016-12-15

    The analysis of the ion chemistry of atmospheric pressure plasmas is essential to evaluate ionic reaction pathways during plasma-surface or plasma-analyte interactions. In this contribution, the ion chemistry of a radio-frequency atmospheric pressure plasma jet (μ-APPJ) operated in helium is investigated by mass spectrometry (MS). It is found, that the ion composition is extremely sensitive to impurities such as N{sub 2}, O{sub 2} and H{sub 2}O. Without gas purification, protonated water cluster ions of the form H{sup +}(H{sub 2}O){sub n} are dominating downstream the positive ion mass spectrum. However, even after careful feed gas purification to the sub-ppm level using a molecular sieve trap and a liquid nitrogen trap as well as operation of the plasma in a controlled atmosphere, the positive ion mass spectrum is strongly influenced by residual trace gases. The observations support the idea that species with a low ionization energy serve as a major source of electrons in atmospheric pressure helium plasmas. Similarly, the neutral density of atomic nitrogen measured by MS in a He/N{sub 2} mixture is varying up to a factor 3, demonstrating the significant influence of impurities on the neutral species chemistry as well. (orig.)

  11. Differential effect of non-thermal atmospheric-pressure plasma on angiogenesis

    Directory of Open Access Journals (Sweden)

    Beate Haertel

    2014-06-01

    Full Text Available Angiogenesis is a special feature in wound healing and carcinogenesis. For improving wound healing angiogenesis should be promoted, whereas in treating tumors it should be inhibited.Depending on several factors physical non-thermal plasmas can stimulate or inhibit cellular processes and can, thereby, influence angiogenesis. This study focused on effects of plasma on angiogenesis in the chick embryo chorioallantoic membrane (CAM assay and rat aortic ring (AOR test, in which plasma-treated PBS or medium was applied. ImageJ was used to analyze vessel area and branching of vessels of CAM’s. Aortic rings (LEW.1W, WOK.W rats embedded in Matrigel were analyzed by a newly-developed semi-quantitative method to quantify vessel sprouting from aortic rings. In both models spontaneous vessel formation was detected. Vessel area and branching in CAM’s were significantly enhanced by 120-s-plasma-treated PBS compared to untreated controls. This result was comparable with the effect of the growth factor VEGF. No effect of plasma on vessel sprouting from AOR prepared from LEW.1W rats was detected, while it was significantly inhibited in rings of WOK.W rats. Dexamethasone inhibited vessel sprouting from AOR of both rat strains. In conclusion, angiogenic response to plasma was found to be differentially influenced, depending on the models used and on the rat strain in the AOR test. It will now be of importance to learn how plasma has to be designed for either pro- or anti-angiogenic responses.

  12. Time-related surface modification of denture base acrylic resin treated by atmospheric pressure cold plasma.

    Science.gov (United States)

    Qian, Kun; Pan, Hong; Li, Yinglong; Wang, Guomin; Zhang, Jue; Pan, Jie

    2016-01-01

    The changes of denture base acrylic resin surface properties under cold plasma and the relationships with time were investigated. Cold plasma treated the specimens for 30 s, 60 s, 90 s, and 120 s, respectively. Water contact angles were measured immediately after the treatment, 48 h, 15 days and 30 days later. Surface roughness was measured with 3-D laser scanning microscope. Candida albicans adherence was evaluated by CFU counting. Chemical composition was monitored by X-ray photoelectron spectroscopy analysis. Water contact angle reduced after treated for 30 s. No changes were observed with time prolonged, except the durability. There were no differences in roughness among all groups. However, treatment groups showed significantly lower C. albicans adherence. XPS demonstrated a decrease in C/O, and this reduction was affected by treatment time. Cold plasma was an effective means of increasing hydrophilicity of acrylic resin and reducing C. albicans adherence without affecting physical properties.

  13. Effect of atmospheric-pressure plasma treatment on the adhesion characteristics of screen-printed Ag nanoparticles on polyimide.

    Science.gov (United States)

    Park, Bum-Geun; Kim, Kwang-Seok; Jung, Kwang-Ho; Jung, Seung-Boo

    2014-12-01

    We investigated the adhesion characteristics of screen-printed silver (Ag) tracks on polyimide (PI) treated by atmospheric-pressure plasma (APP). Oxygen plasma was applied to the PI surface, and the APP-treated surface was exposed to air for various periods of time in order to evaluate the sustainability of the APP treatment. The adhesion of the Ag/PI interface was measured using a roll-type 90 degrees peel test. The peel strength was dramatically increased by the APP treatment, but the strength decreased by around 62.7% when the APP-treated PI surface was exposed to air for 2 h. The peeled PI surface showed ductile fracture immediately after the APP treatment; however, after 2 h of exposure to air, the fracture behavior returned what was observed before the APP treatment. To analyze the deterioration of adhesion, the interface between the printed Ag track and the APP-treated PI was investigated physically and chemically. The surface morphology became rougher after the APP treatment, but the roughness slightly decreased after being exposed to air for 2 h. X-ray photoelectron spectroscopy (XPS) was used to investigate the chemical bonding of the printed Ag and the PI interface. XPS analyses show that the concentration of oxygen-containing groups decreased as the exposure time to air increased.

  14. A dominant role of oxygen additive on cold atmospheric-pressure He + O{sub 2} plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Aijun; Liu, Dingxin, E-mail: liudingxin@gmail.com, E-mail: xhw@mail.xjtu.edu.cn; Rong, Mingzhe; Wang, Xiaohua, E-mail: liudingxin@gmail.com, E-mail: xhw@mail.xjtu.edu.cn [Centre for Plasma Biomedicine, State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Kong, Michael G. [Centre for Plasma Biomedicine, State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia 23508 (United States); Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia 23529 (United States)

    2014-08-15

    We present in this paper how oxygen additive impacts on the cold atmospheric-pressure helium plasmas by means of a one-dimensional fluid model. For the oxygen concentration [O{sub 2}] > ∼0.1%, the influence of oxygen on the electron characteristics and the power dissipation becomes important, e.g., the electron density, the electron temperature in sheath, the electron-coupling power, and the sheath width decreasing by 1.6 to 16 folds with a two-log increase in [O{sub 2}] from 0.1% to 10%. Also the discharge mode evolves from the γ mode to the α mode. The reactive oxygen species are found to peak in the narrow range of [O{sub 2}] = 0.4%–0.9% in the plasmas, similar to their power-coupling values. This applies to their wall fluxes except for those of O* and O{sub 2}{sup −}. These two species have very short lifetimes, thus only when generated in boundary layers within several micrometers next to the electrode can contribute to the fluxes. The dominant reactive oxygen species and the corresponding main reactions are schematically presented, and their relations are quantified for selected applications.

  15. Influence of ambient air on the flowing afterglow of an atmospheric pressure Ar/O2 radiofrequency plasma

    CERN Document Server

    Duluard, C Y; Hubert, J; Reniers, F

    2016-01-01

    The influence of ambient air on the flowing afterglow of an atmospheric pressure Ar/O2 radiofrequency plasma has been investigated experimentally. Spatially resolved mass spectrometry and laser induced fluorescence on OH radicals were used to estimate the intrusion of air in between the plasma torch and the substrate as a function of the torch-to-substrate separation distance. No air is detected, within the limits of measurement uncertainties, for separation distances smaller than 5 mm. For larger distances, the effect of ambient air can no longer be neglected, and radial gradients in the concentrations of species appear. The Ar 4p population, determined through absolute optical emission spectroscopy, is seen to decrease with separation distance, whereas a rise in emission from the N2(C--B) system is measured. The observed decay in Ar 4p and N2(C) populations for separation distances greater than 9mm is partly assigned to the increasing collisional quenching rate by N2 and O2 molecules from the entrained air....

  16. Surface Modification of Polypropylene Microporous Membrane by Atmospheric-pressure Plasma Induced N-vinyl-2-pyrrolidone Graft Polymerization

    Institute of Scientific and Technical Information of China (English)

    ZHONG Shaofeng

    2012-01-01

    Membrane surfaces modified with poly(N-vinyl-2-pyrrolidone) (PNVP) can be endowed with hydrophilicity,biocompatibility and functionality.In this work,atmospheric pressure dielectric barrier discharge plasma graft polymerization of N-vinyl-2-pyrrolidone (NVP) onto polypropylene (PP) microporous membrane surface was studied.The experimental results reveal that plasma treatment conditions,such as discharge power,treatment time and adsorbed NVP amount,have remarkable effects on the grafting degree of NVP.Structural and morphological changes on the membrane surfaces were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (FT-IR/ATR),X-ray photoelectron spectroscope (XPS) and field emission scanning electron microscopy (FE-SEM).Water contact angles of the membrane surfaces were also measured by the sessile drop method.Water contact angles on the membrane surfaces decrease with the increase of NVP grafting degree,which indicates an enhanced hydrophilicity for the modified membranes.The effects of grafting degrees on pure water fluxes were also measured.It is shown that pure water fluxes increase with grafting degree firstly and then decrease adversely.Finally,filtration of bovine serum albumin (BSA) solution and platelets adhesion of the PNVP modified membranes show good protein resistance and potential biocompatibility due to the enhancement of surface hydrophilicity.

  17. Humidity-independent conducting polyaniline films synthesized using advanced atmospheric pressure plasma polymerization with in-situ iodine doping

    Science.gov (United States)

    Park, Choon-Sang; Kim, Do Yeob; Kim, Dong Ha; Lee, Hyung-Kun; Shin, Bhum Jae; Tae, Heung-Sik

    2017-01-01

    This study reports on the synthesis and characterization of conducting polyaniline (PANI) thin films when using advanced atmospheric pressure plasma jets (APPJs). A simple method for synthesizing conducting polymers (CPs) with humidity-independent characteristics is introduced using advanced APPJs and an in-situ iodine doping method. In the case of ex-situ I2 doping, a humidity effect study showed that increasing the relative humidity produced significant changes in the electrical resistance (R) of the PANI, indicating strong humidity-dependent characteristics similar to conventional CPs. In contrast, in the case of in-situ I2 doping, the R and sensitivity of the PANI remained essentially unchanged when increasing the relative humidity, except for a very low sensitivity of 0.5% under 94% relative humidity. In addition, the R for the PANI with in-situ I2 doping showed no aging effect, while the R for the ex-situ-doped PANI increased dramatically over time. Thus, it is anticipated that the use of in-situ doping during plasma polymerization can be widely used to design stable and high-performance CPs with humidity-independent characteristics for a variety of applications.

  18. Thermalization of rotational states of NO A(2)Σ+(v = 0) in an atmospheric pressure plasma.

    Science.gov (United States)

    van Gessel, A F H; Bruggeman, P J

    2013-05-28

    Laser induced fluorescence (LIF) measurements of nitric oxide (NO) are performed in an atmospheric pressure microwave plasma jet, operated with a mixture of He and 3% air. The fluorescence signal of NO A(2)Σ(+)(v = 0) is measured time and fluorescence wavelength resolved. Based on the evolution of the rotational spectrum at different positions in the plasma, we determined the thermalization time of the rotational distribution of NO A after pumping a single transition, at temperatures in the range 300-1500 K. Also, a LIF-RET (rotational energy transfer) model is developed to simulate the RET and to calculate the thermalization time. The RET rate coefficients are calculated using the energy corrected sudden-exponential power scaling law. It was found that it is necessary to take the fine structure of the rotational states into account. At room temperature the results of the measurement and the simulation are consistent, and the thermalization occurs during the laser pulse (11 ± 1 ns). At elevated temperatures the measurements show a large increase in thermalization time, up to 35 ± 4 ns at 1474 K. This time is much longer than the laser pulse, and of the order of the NO A lifetime. This means that for spectroscopy measurements of the rotational states of NO A, the RET has to be taken into account to derive gas temperatures from the rotational distribution of NO A.

  19. Inactivation of Shiga toxin-producing Escherichia coli O104:H4 using cold atmospheric pressure plasma.

    Science.gov (United States)

    Baier, Matthias; Janssen, Traute; Wieler, Lothar H; Ehlbeck, Jörg; Knorr, Dietrich; Schlüter, Oliver

    2015-09-01

    From cultivation to the end of the post-harvest chain, heat-sensitive fresh produce is exposed to a variety of sources of pathogenic microorganisms. If contaminated, effective gentle means of sanitation are necessary to reduce bacterial pathogen load below their infective dose. The occurrence of rare or new serotypes raises the question of their tenacity to inactivation processes. In this study the antibacterial efficiency of cold plasma by an atmospheric pressure plasma-jet was examined against the Shiga toxin-producing outbreak strain Escherichia coli O104:H4. Argon was transformed into non-thermal plasma at a power input of 8 W and a gas flow of 5 L min(-1). Basic tests were performed on polysaccharide gel discs, including the more common E. coli O157:H7 and non-pathogenic E. coli DSM 1116. At 5 mm treatment distance and 10(5) cfu cm(-2) initial bacterial count, plasma reduced E. coli O104:H4 after 60 s by 4.6 ± 0.6 log, E. coli O157:H7 after 45 s by 4.5 ± 0.6 log, and E. coli DSM 1116 after 30 s by 4.4 ± 1.1 log. On the surface of corn salad leaves, gentle plasma application at 17 mm reduced 10(4) cfu cm(-2) of E. coli O104:H4 by 3.3 ± 1.1 log after 2 min, whereas E. coli O157:H7 was inactivated by 3.2 ± 1.1 log after 60 s. In conclusion, plasma treatment has the potential to reduce pathogens such as E. coli O104:H4 on the surface of fresh produce. However, a serotype-specific adaptation of the process parameters is required.

  20. Production characteristics of reactive oxygen/nitrogen species in water using atmospheric pressure discharge plasmas

    Science.gov (United States)

    Takahashi, Kazuhiro; Satoh, Kohki; Itoh, Hidenori; Kawaguchi, Hideki; Timoshkin, Igor; Given, Martin; MacGregor, Scott

    2016-07-01

    A pulsed discharge, a DC corona discharge, and a plasma jet are separately generated above a water surface, and reactive oxygen species and reactive nitrogen species (ROS/RNS) in the water are investigated. ROS/RNS in water after the sparging of the off-gas of a packed-bed dielectric barrier discharge (PB-DBD) are also investigated. H2O2, NO2 -, and NO3 - are detected after plasma exposure and only NO3 - after off-gas sparging. Short-lifetime species in plasma are found to play an important role in H2O2 and NO2 - production and long-lifetime species in NO3 - production. NO x may inhibit H2O2 production through OH consumption to produce HNO2 and HNO3. O3 does not contribute to ROS/RNS production. The pulsed plasma exposure is found to be effective for the production of H2O2 and NO2 -, and the off-gas sparging of the PB-DBD for the production of NO3 -.

  1. Enhancement of carbon-steel peel adhesion to rubber blend using atmospheric pressure plasma

    Science.gov (United States)

    Kršková, Jana; Skácelová, Dana; Kováčik, Dušan; Ráhel', Jozef; Pret'o, Jozef; Černák, Mirko

    2016-08-01

    The surface of carbon-steel plates was modified by non-equilibrium plasma of diffuse coplanar surface barrier discharge (DCSBD) in order to improve the adhesive properties to the NR (natural rubber) green rubber compound. The effect of different treatment times as well as different input power and frequency of supplied high voltage was investigated. The samples were characterized using contact angle and surface free energy measurement, measurement of adhesive properties, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Surface chemical composition was studied by energy-dispersive X-ray spectroscopy (EDX). Significant increase in wettability was observed even after 2 s of plasma exposure. The surface modification was confirmed also by peel test, where the best results were obtained for 6 s of plasma treatment. In addition the ageing effect was studied to investigate the durability of modification, which is crucial for the industrial applications. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  2. Wettability and sizing property improvement of raw cotton yarns treated with He/O{sub 2} atmospheric pressure plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Sun Shiyuan [Key Laboratory of Textile Science and Technology, Ministry of Education, China, College of Textiles, Donghua University, Shanghai 201620 (China); College of Textiles and Clothing Engineering, Dezhou University, Shandong 253023 (China); Sun Jie; Yao Lan [Key Laboratory of Textile Science and Technology, Ministry of Education, China, College of Textiles, Donghua University, Shanghai 201620 (China); Qiu Yiping, E-mail: ypqiu@dhu.edu.cn [Key Laboratory of Textile Science and Technology, Ministry of Education, China, College of Textiles, Donghua University, Shanghai 201620 (China)

    2011-01-01

    Raw cotton fiber is water repellent due to the existence of the water repellent cuticle layer. This study is designed to systematically investigate how He/O{sub 2} atmospheric pressure plasma jet (APPJ) treatments influence the wettability and the sizing property of cotton yarns. Water absorption time and adhesion of the sizing agent to the cotton roving are used to evaluate the improvement of wettability and sizing property of the yarn respectively. The water absorption time decreases with the increase of the treatment time and the oxygen flow rate, and the decrease of the jet to substrate distance (JTSD). An optimal water absorption time of 0.8 s is obtained with a treatment time of 20 s, JTSD of 1 mm and O{sub 2} flow rate of 0.2 L/min. Scanning electron microscopy (SEM) shows that the etching effect increases with the decrease of the JTSD and X-ray photoelectron spectroscopy (XPS) presents increased oxygen contents after the plasma treatments. An increase of O-C=O bonds while a decrease of C-OH/C-O-C bonds are observed when the JTSD is set at 2 mm. However, a remarkable increase of both C-OH/C-O-C and O-C=O bonds are achieved when the JTSD is 1 mm. The roving impregnation test results show a nearly doubled adhesion of sizing and a slightly improved breaking elongation, indicating that the plasma treatment does effectively enhance the bonding strength between the fiber and the sizing.

  3. Gas chromatography interfaced with atmospheric pressure ionization-quadrupole time-of-flight-mass spectrometry by low-temperature plasma ionization

    DEFF Research Database (Denmark)

    Norgaard, Asger W.; Kofoed-Sorensen, Vivi; Svensmark, Bo

    2013-01-01

    A low temperature plasma (LTP) ionization interface between a gas chromatograph (GC) and an atmospheric pressure inlet mass spectrometer, was constructed. This enabled time-of-flight mass spectrometric detection of GC-eluting compounds. The performance of the setup was evaluated by injection...

  4. Atmospheric-pressure plasma jet induces DNA double-strand breaks that require a Rad51-mediated homologous recombination for repair in Saccharomyces cerevisiae.

    Science.gov (United States)

    Lee, Yoonna; Kim, Kangil; Kang, Kyu-Tae; Lee, Jong-Soo; Yang, Sang Sik; Chung, Woo-Hyun

    2014-10-15

    Non-thermal plasma generated under atmospheric pressure produces a mixture of chemically reactive molecules and has been developed for a number of biomedical applications. Recently, plasma jet has been proposed as novel cancer therapies based on the observation that free radicals generated by plasma jet induce mitochondria-mediated apoptotic cell death. We show here that air plasma jet induces DNA double-strand breaks (DSBs) in yeast chromosomes leading to genomic instability and loss of viability, which are alleviated by Rad51, the yeast homolog of Escherichiacoli RecA recombinase, through DNA damage repair by a homologous recombination (HR) process. Hypersensitivity of rad51 mutant to air plasma was not restored by antioxidant treatment unlike sod1 mutant that was highly sensitive to reactive oxygen species (ROS) challenge, suggesting that plasma jet induces DSB-mediated cell death independent of ROS generation. These results may provide a new insight into the mechanism of air plasma jet-induced cell death.

  5. Modification of the Steel Surface Treated by a Volume Discharge Plasma in Nitrogen at Atmospheric Pressure

    Science.gov (United States)

    Erofeev, M. V.; Shulepov, M. A.; Ivanov, Yu. F.; Oskomov, K. V.; Tarasenko, V. F.

    2016-03-01

    Effect of volume discharge plasma initiated by an avalanche electron beam on the composition, structure, and properties of the surface steel layer is investigated. Voltage pulses with incident wave amplitude up to 30 kV, full width at half maximum of about 4 ns, and wave front of about 2.5 ns were applied to the gap with an inhomogeneous electric field. Changes indicating the hardening effect of the volume discharge initiated by an avalanche electron beam are revealed in St3-grade steel specimens treated by the discharge of this type.

  6. Deposition of Antimicrobial Copper-Rich Coatings on Polymers by Atmospheric Pressure Jet Plasmas

    Directory of Open Access Journals (Sweden)

    Jana Kredl

    2016-04-01

    Full Text Available Inanimate surfaces serve as a permanent reservoir for infectious microorganisms, which is a growing problem in areas in everyday life. Coating of surfaces with inorganic antimicrobials, such as copper, can contribute to reduce the adherence and growth of microorganisms. The use of a DC operated air plasma jet for the deposition of copper thin films on acrylonitrile butadiene styrene (ABS substrates is reported. ABS is a widespread material used in consumer applications, including hospitals. The influence of gas flow rate and input current on thin film characteristics and its bactericidal effect have been studied. Results from X-ray photoelectron spectroscopy (XPS and atomic force microscopy confirmed the presence of thin copper layers on plasma-exposed ABS and the formation of copper particles with a size in the range from 20 to 100 nm, respectively. The bactericidal properties of the copper-coated surfaces were tested against Staphylococcus aureus. A reduction in growth by 93% compared with the attachment of bacteria on untreated samples was observed for coverage of the surface with 7 at. % copper.

  7. Thermal plasma properties for Ar-Al, Ar-Fe and Ar-Cu mixtures used in welding plasmas processes: I. Net emission coefficients at atmospheric pressure

    Science.gov (United States)

    Cressault, Y.; Gleizes, A.

    2013-10-01

    This article is devoted to the calculation of the net emission coefficient (NEC) of Ar-Al, Ar-Fe and Ar-Cu mixtures at atmospheric pressure for arc welding processes. The results are given in data tables for temperatures between 3 kK and 30 kK, for five plasma thicknesses (0, 0.5, 1, 2, 5 mm) and ten concentrations of metallic vapours (pure gas, 0.01%, 0.1%, 1%, 5%, 10%, 25%, 50%, 75% and pure metal vapours in mass proportions). The results are in good agreement with most of the works published on the subject for such mixtures. They highlight the influence of three parameters on the radiation of the plasma: the NEC is directly related to temperature and inversely related to plasma radius and is highly sensitive to the presence of metal vapours. Finally, numerical data are supplied in tables in order to develop accurate computational modelling of welding arc and to estimate both qualitatively and quantitatively the influence of each metallic vapour on the size and on the shape of the weld pool.

  8. Degradation of Acid Orange 7 in an Atmospheric-Pressure Plasma-Solution System (Gliding Discharge)

    Science.gov (United States)

    NI, Mingjiang; YANG, Huan; CHEN, Tong; ZHANG, Hao; WU, Angjian; DU, Changming; LI, Xiaodong

    2015-03-01

    In this work, a plasma-solution system was applied to the degradation of Acid Orange 7 (AO7). The effects of initial concentration and type of feed gases (air, oxygen, nitrogen or argon) were studied. As the initial concentration increased from 100 mg/L to 160 mg/L, the discolouration rate of AO7 decreased from 99.3% to 95.9%, whereas the COD removal rate decreased from 37.9% to 22.6%. Air provided the best discolouration and COD removal rates (99.3% and 37.9%, respectively). In the presence of a zero-valent iron (ZVI) catalyst, the AO7 COD removal rate increased to 76.4%. The degradation products were analysed by a GC-MS, revealing that the degradation of the dye molecule was initiated through the cleavage of the -N=N- bond before finally being converted to organic acids. supported by National Natural Science Foundation of China (Nos. 50908237, 51076142) and the Open Foundation of the State Key Laboratory of Clean Energy Utilization of China (No. ZJUCEU2009008)

  9. Physical and chemical interactions at the interface between atmospheric pressure plasmas and aqueous solutions

    Science.gov (United States)

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

    2014-10-01

    Transport and reactions of charged species, neutrals, and photons at the interface between plasmas and liquids must be better quantified. The work presented here combines theoretical and experimental investigations of conditions in the gas and liquid phases in proximity to the interface for various discharges. OES is used to determine rotational and vibrational temperatures of OH, NO, and N2+; the relationship between these temperatures that characterize the distribution of internal energy states and gas and electron kinetic temperatures is considered. The deviation of OH rotational states from equilibrium under high humidity conditions is also presented. In contradiction with findings of other groups, high energy rotational states appear to become underpopulated with increasing humidity. In the aqueous phase, concentrations of longer-lived species such as nitrate, nitrite, hydrogen peroxide, and ozone are determined using ion chromatography and colorimetric methods. Spin-traps and electron paramagnetic resonance (EPR) are investigated for characterization of short-lived aqueous radicals like OH, O2-, NO, and ONOO-. Finally, experimental results are compared to a numerical model which couples transport and reactions within and between the bulk gas and liquid phases.

  10. Influence of charge accumulation on a dielectric capillary atmospheric pressure plasma jet

    Science.gov (United States)

    Sands, Brian; Huang, Shih; Speltz, Jared; Niekamp, Matthew; Ganguly, Biswa

    2011-10-01

    Using a single ring electrode configuration and a positive unipolar pulsed voltage source, we examine the influence of the dielectric barrier on the distribution of ionization in a streamer-like dielectric capillary plasma jet utilizing a rare gas flow as a function of anode placement and pulse repetition frequency. At low frequencies, when the anode is recessed at least 5 mm along the capillary, two regions of enhanced ionization can be resolved near the anode and near the capillary tip that are associated with two distinct peaks in the discharge current and locally increased emission intensity in the residual streamer channel. With the anode placed ~20 mm from the capillary tip, the two current peaks were ~13 mA. Increasing the frequency between 6 and 10 kHz, the capillary tip enhancement expanded towards the anode and concentrated there at higher frequencies. The discharge current over this frequency range rose to 18 mA and was increasingly dominated by the earlier peak associated with ionization near the anode. This increased charging of the dielectric surface and reduced the potential available to the ionization front outside the capillary as indicated by a 25% drop in velocity and reduced emission intensity. The surface charging effect is visualized at discharge inception using a Phantom high-frame-rate CCD camera.

  11. Separation of VUV/UV photons and reactive particles in the effluent of a He/O2 atmospheric pressure plasma jet

    CERN Document Server

    Schneider, S; Narberhaus, F; Bandow, J E; Denis, B; Benedikt, J

    2011-01-01

    Cold atmospheric pressure plasmas can be used for treatment of living tissues or for inactivation of bacteria or biological macromolecules. The treatment is usually characterized by a combined effect of UV and VUV radiation, reactive species, and ions. This combination is usually beneficial for the effectiveness of the treatment but it makes the study of fundamental interaction mechanisms very difficult. Here we report on an effective separation of VUV/UV photons and heavy reactive species in the effluent of a micro scale atmospheric pressure plasma jet ($\\mu$-APPJ). The separation is realized by an additional flow of helium gas under well-defined flow conditions, which deflects heavy particles in the effluent without affecting the VUV and UV photons. Both components of the effluent, the photons and the reactive species, can be used separately or in combination for sample treatment. The results of treatment of a model plasma polymer film and vegetative Bacillus subtilis and Escherichia coli cells are shown an...

  12. A study of the effect on human mesenchymal stem cells of an atmospheric pressure plasma source driven by different voltage waveforms

    Science.gov (United States)

    Laurita, R.; Alviano, F.; Marchionni, C.; Abruzzo, P. M.; Bolotta, A.; Bonsi, L.; Colombo, V.; Gherardi, M.; Liguori, A.; Ricci, F.; Rossi, M.; Stancampiano, A.; Tazzari, P. L.; Marini, M.

    2016-09-01

    The effect of an atmospheric pressure non-equilibrium plasma on human mesenchymal stem cells was investigated. A dielectric barrier discharge non-equilibrium plasma source driven by two different high-voltage pulsed generators was used and cell survival, senescence, proliferation, and differentiation were evaluated. Cells deprived of the culture medium and treated with nanosecond pulsed plasma showed a higher mortality rate, while higher survival and retention of proliferation were observed in cells treated with microsecond pulsed plasma in the presence of the culture medium. While a few treated cells showed the hallmarks of senescence, unexpected delayed apoptosis ensued in cells exposed to plasma-treated medium. The plasma treatment did not change the expression of OCT4, a marker of mesenchymal stem cell differentiation.

  13. Influence of He/O{sub 2} atmospheric pressure plasma jet treatment on subsequent wet desizing of polyacrylate on PET fabrics

    Energy Technology Data Exchange (ETDEWEB)

    Li Xuming [Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); College of Textile and Clothing, Shaoxing University, Shaoxing 312000 (China); Lin Jun [Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Qiu Yiping, E-mail: ypqiu@dhu.edu.cn [Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China)

    2012-01-15

    The influence of He/O{sub 2} atmospheric pressure plasma jet (APPJ) treatment on subsequent wet desizing of polyacrylate on PET fabrics was studied in the present paper. Weight loss results indicated that the weight loss increased with an increase of plasma treatment time. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) showed an increased surface roughness after the plasma treatment. SEM also showed that the fiber surfaces were as clean as unsized fibers after 35 s treatment followed by NaHCO{sub 3} desizing. X-ray photoelectron spectroscopy (XPS) analysis indicated that oxygen-based functional groups increased for the plasma treated polyacrylate sized fabrics. The percent desizing ratio (PDR) results showed that more than 99% PDR was achieved after 65 s plasma treatment followed by a 5 min NaHCO{sub 3} desizing. Compared to conventional wet desizing, indicating that plasma treatment could significantly reduce desizing time.

  14. Atmospheric pressure plasma-initiated chemical vapor deposition (AP-PiCVD) of poly(diethylallylphosphate) coating: a char-forming protective coating for cellulosic textile.

    Science.gov (United States)

    Hilt, Florian; Boscher, Nicolas D; Duday, David; Desbenoit, Nicolas; Levalois-Grützmacher, Joëlle; Choquet, Patrick

    2014-01-01

    An innovative atmospheric pressure chemical vapor deposition method toward the deposition of polymeric layers has been developed. This latter involves the use of a nanopulsed plasma discharge to initiate the free-radical polymerization of an allyl monomer containing phosphorus (diethylallylphosphate, DEAP) at atmospheric pressure. The polymeric structure of the film is evidence by mass spectrometry. The method, highly suitable for the treatment of natural biopolymer substrate, has been carried out on cotton textile to perform the deposition of an efficient and conformal protective coating.

  15. Changes in the electro-physical properties of MCT epitaxial films affected by a plasma volume discharge induced by an avalanche beam in atmospheric-pressure air

    Science.gov (United States)

    Grigoryev, D. V.; Voitsekhovskii, A. V.; Lozovoy, K. A.; Tarasenko, V. F.; Shulepov, M. A.

    2015-11-01

    In this paper the influence of the plasma volume discharge of nanosecond duration formed in a non-uniform electric field at atmospheric pressure on samples of epitaxial films HgCdTe (MCT) films are discussed. The experimental data show that the action of pulses of nanosecond volume discharge in air at atmospheric pressure leads to changes in the electrophysical properties of MCT epitaxial films due to formation of a near-surface high- conductivity layer of the n-type conduction. The preliminary results show that it is possible to use such actions in the development of technologies for the controlled change of the properties of MCT.

  16. MS2 virus inactivation by atmospheric-pressure cold plasma using different gas carriers and power levels.

    Science.gov (United States)

    Wu, Yan; Liang, Yongdong; Wei, Kai; Li, Wei; Yao, Maosheng; Zhang, Jue; Grinshpun, Sergey A

    2015-02-01

    In this study, airborne MS2 bacteriophages were exposed for subsecond time intervals to atmospheric-pressure cold plasma (APCP) produced using different power levels (20, 24, and 28 W) and gas carriers (ambient air, Ar-O2 [2%, vol/vol], and He-O2 [2%, vol/vol]). In addition, waterborne MS2 viruses were directly subjected to the APCP treatment for up to 3 min. MS2 viruses with and without the APCP exposure were examined by scanning electron microscopy (SEM), reverse transcription-PCR (RT-PCR), and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Viral inactivation was shown to exhibit linear relationships with the APCP generation power and exposure time (R(2) > 0.95 for all energy levels tested) up to 95% inactivation (1.3-log reduction) after a subsecond airborne exposure at 28 W; about the same inactivation level was achieved for waterborne viruses with an exposure time of less than 1 min. A larger amount of reactive oxygen species (ROS), such as atomic oxygen, in APCP was detected for a higher generation power with Ar-O2 and He-O2 gas carriers. SEM images, SDS-PAGE, and agarose gel analysis of exposed waterborne viruses showed various levels of damage to both surface proteins and their related RNA genes after the APCP exposure, thus leading to the loss of their viability and infectivity.

  17. Protective effect of atmospheric pressure plasma on oxidative stress-induced neuronal injuries: an in vitro study

    Science.gov (United States)

    Yan, Xu; Qiao, Yajun; Ouyang, Jiting; Jia, Mei; Li, Jiaxin; Yuan, Fang

    2017-03-01

    Atmospheric pressure plasma jet (APPJ) can produce biological active species for biomedical applications. This work proves direct evidence of the protective effects of APPJ against oxidative stress. SH-SY5Y cells, a commonly used cell model for the study of neurotoxicity and neuroprotection, were treated with APPJ for different durations. Then, cells were exposed to 200 µM H2O2 for 24 h and cell viability was measured using a CCK-8 kit. Changes in cell apoptosis were further confirmed by calcein-AM fluorescence imaging and flow cytometry. Extracellular NO production was detected using the Griess method. The results showed that APPJ protected SH-SY5Y from H2O2-induced apoptosis in a time-dependent manner. Moreover, extracellular NO production was significantly increased with the APPJ treatment. The results show in vitro that APPJ treatment could protect SH-SY5Y cells from oxidative stress by reducing cell apoptosis, which might be related to the reactive nitrogen species induced by the APPJ treatment. Our results indicate that the APPJ may have therapeutic potential as a novel ‘NO donor drug’ in neuroprotection and in the treatment of neurodegenerative diseases.

  18. Fabrication of a Transparent Anti-stain Thin Film Using an Atmospheric Pressure Cold Plasma Deposition System

    Directory of Open Access Journals (Sweden)

    Suzaki Y.

    2013-08-01

    Full Text Available Recently, outdoor-constructed solar panels have a problem such as power generation efficiency is reduced by the face plate dirt. On the other hand, electronic touch panels have a problem such as deterioration of visibility of the screen by finger grease stain. To solve these problems, we need to fabricate the anti-stain surfaces which have superhydrophobic and oil-repellent abilities without spoiling the transparency of the transparent substrate. In this study, we fabricated lotus leaves like surface on a glass substrate. Firstly, SiO2 particles of ca. 100 nm diameter were arranged on the glass substrates. Secondly, to obtain the fractal-like structure (ultra-micro-rough structure on the surface, ZnO thin film having a columnar structure was fabricated on the SiO2 particles by using an atmospheric pressure cold plasma deposition system. By using these processes, the ZnO columns formed radiantly on the spherical surface of the SiO2 particles. Furthermore, without spoiling the ultra-micro-rough structure, a transparent anti-stain monolayer with low surface energy was prepared by using a chemical adsorption technique onto the surface. Average value of the water droplet contact angles of the samples fabricated was 151.8 deg. Field emission scanning electron microscope (FE-SEM observation reviled that this sample has a raspberry structure in which columnar structure has grown radially on the SiO2 particles.

  19. Finishing of AT-cut quartz crystal wafer with nanometric thickness uniformity by pulse-modulated atmospheric pressure plasma etching.

    Science.gov (United States)

    Yamamura, Kazuya; Ueda, Masaki; Shibahara, Masafumi; Zettsu, Nobuyuki

    2011-04-01

    Quartz resonator is a very important device to generate a clock frequency for information and telecommunication system. Improvement of the productivity of the quartz resonator is always required because a huge amount of the resonator is demanded for installing to various electronic devices. Resonance frequency of the quartz resonator is decided by the thickness of the quartz crystal wafer. Therefore, it is necessary to uniform the thickness distribution of the wafer with nanometric level. We have proposed the improvement technique of the thickness distribution of the quartz crystal wafer by numerically controlled correction using atmospheric pressure plasma which is non-contact and chemical removal technique. Heating effects of the quartz wafer in the removal rate and the correction accuracy were investigated. The heating of the substrate and compensate of the scanning speed of the worktable according to the variation of the surface temperature enabled an increase of 50% in the etching rate and 10-nanometric-level accuracy in the correction of the thickness distribution of the quartz wafer, respectively.

  20. Novel atmospheric pressure plasma device releasing atomic hydrogen: reduction of microbial-contaminants and OH radicals in the air

    Science.gov (United States)

    Nojima, Hideo; Park, Rae-Eun; Kwon, Jun-Hyoun; Suh, Inseon; Jeon, Junsang; Ha, Eunju; On, Hyeon-Ki; Kim, Hye-Ryung; Choi, Kyoung Hui; Lee, Kwang-Hee; Seong, Baik-Lin; Jung, Hoon; Kang, Shin Jung; Namba, Shinichi; Takiyama, Ken

    2007-01-01

    A novel atmospheric pressure plasma device releasing atomic hydrogen has been developed. This device has specific properties such as (1) deactivation of airborne microbial-contaminants, (2) neutralization of indoor OH radicals and (3) being harmless to the human body. It consists of a ceramic plate as a positive ion generation electrode and a needle-shaped electrode as an electron emission electrode. Release of atomic hydrogen from the device has been investigated by the spectroscopic method. Optical emission of atomic hydrogen probably due to recombination of positive ions, H+(H2O)n, generated from the ceramic plate electrode and electrons emitted from the needle-shaped electrode have been clearly observed in the He gas (including water vapour) environment. The efficacy of the device to reduce airborne concentrations of influenza virus, bacteria, mould fungi and allergens has been evaluated. 99.6% of airborne influenza virus has been deactivated with the operation of the device compared with the control test in a 1 m3 chamber after 60 min. The neutralization of the OH radical has been investigated by spectroscopic and biological methods. A remarkable reduction of the OH radical in the air by operation of the device has been observed by laser-induced fluorescence spectroscopy. The cell protection effects of the device against OH radicals in the air have been observed. Furthermore, the side effects have been checked by animal experiments. The harmlessness of the device has been confirmed.

  1. Time-dependent effects of ultraviolet and nonthermal atmospheric pressure plasma on the biological activity of titanium

    Science.gov (United States)

    Choi, Sung-Hwan; Jeong, Won-Seok; Cha, Jung-Yul; Lee, Jae-Hoon; Yu, Hyung-Seog; Choi, Eun-Ha; Kim, Kwang-Mahn; Hwang, Chung-Ju

    2016-09-01

    Here, we evaluated time-dependent changes in the effects of ultraviolet (UV) and nonthermal atmospheric pressure plasma (NTAPPJ) on the biological activity of titanium compared with that of untreated titanium. Grade IV machined surface titanium discs (12-mm diameter) were used immediately and stored up to 28 days after 15-min UV or 10-min NTAPPJ treatment. Changes of surface characteristics over time were evaluated using scanning electron microscopy, surface profiling, contact angle analysis, X-ray photoelectron spectroscopy, and surface zeta-potential. Changes in biological activity over time were as determined by analysing bovine serum albumin adsorption, MC3T3-E1 early adhesion and morphometry, and alkaline phosphatase (ALP) activity between groups. We found no differences in the effects of treatment on titanium between UV or NTAPPJ over time; both treatments resulted in changes from negatively charged hydrophobic (bioinert) to positively charged hydrophilic (bioactive) surfaces, allowing enhancement of albumin adsorption, osteoblastic cell attachment, and cytoskeleton development. Although this effect may not be prolonged for promotion of cell adhesion until 4 weeks, the effects were sufficient to maintain ALP activity after 7 days of incubation. This positive effect of UV and NTAPPJ treatment can enhance the biological activity of titanium over time.

  2. Effects of metastable species in helium and argon atmospheric pressure plasma jets (APPJs) on inactivation of periodontopathogenic bacteria

    Science.gov (United States)

    Yoon, Sung-Young; Kim, Kyoung-Hwa; Seol, Yang-Jo; Kim, Su-Jeong; Bae, Byeongjun; Huh, Sung-Ryul; Kim, Gon-Ho

    2016-05-01

    The helium and argon have been widely used as discharge gases in atmospheric pressure plasma jets (APPJs) for bacteria inactivation. The APPJs show apparent different in bullet propagation speed and bacteria inactivation rate apparently vary with discharge gas species. This work shows that these two distinctive features of APPJs can be linked through one factor, the metastable energy level. The effects of helium and argon metastable species on APPJ discharge mechanism for reactive oxygen nitrogen species (RONS) generation in APPJs are investigated by experiments and numerical estimation. The discharge mechanism is investigated by using the bullet velocity from the electric field which is obtained with laser induced fluorescence (LIF) measurement. The measured electric field also applied on the estimation of RONS generation, as electron energy source term in numerical particle reaction. The estimated RONS number is verified by comparing NO and OH densities to the inactivation rate of periodontitis bacteria. The characteristic time for bacteria inactivation of the helium-APPJ was found to be 1.63 min., which is significantly less than that of the argon-APPJ, 12.1 min. In argon-APPJ, the argon metastable preserve the energy due to the lack of the Penning ionization. Thus the surface temperature increase is significantly higher than helium-APPJ case. It implies that the metastable energy plays important role in both of APPJ bullet propagation and bacteria inactivation mechanism.

  3. Development of hydrophilic dental wax without surfactant using a non-thermal air atmospheric pressure plasma jet

    Science.gov (United States)

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

    2014-06-01

    Dental wax (DW), a low-melting and high-molecular-weight organic mixture, is widely used in dentistry for forming moulds of teeth. Hydrophilicity is an important property for DW, as a wet dental investment is used to surround the wax before wax burnout is performed. However, recent attempts to improve the hydrophilicity of DW using a surfactant have resulted in the reduced mechanical properties of the dental investment, leading to the failure of the dental restoration. This study applied a non-thermal air atmospheric pressure plasma jet (AAPPJ) for DW surface treatment and investigated its effect on both DW hydrophilicity and the dental investment's mechanical properties. The results showed that the application of the AAPPJ significantly improved the hydrophilicity of the DW, and that the results were similar to that of cleaner-treated DW using commercially available products with surfactant. A surface chemical analysis indicated that the improvement of hydrophilicity was related to an increase in the number of oxygen-related bonds on the DW surface following the removal of carbon hydrate in both AAPPJ and cleaner-treated DW. However, cleaner treatment compromised the mechanical property of the dental investment when the dental investment was in contact with the treated DW, while the AAPPJ treatment did not. Therefore, the use of AAPPJ to treat DW is a promising method for accurate dental restoration, as it induces an improvement in hydrophilicity without harming the dental investment.

  4. Feasibility study of surface-modified carbon cloth electrodes using atmospheric pressure plasma jets for microbial fuel cells

    Science.gov (United States)

    Chang, Shih-Hang; Liou, Jyun-Sian; Liu, Jung-Liang; Chiu, Yi-Fan; Xu, Chang-Han; Chen, Bor-Yann; Chen, Jian-Zhang

    2016-12-01

    This study investigated the surface and electrochemical properties of carbon cloth electrodes surface-modified by using atmospheric pressure plasma jets (APPJs) for applications involving microbial fuel cells (MFCs). APPJ treatment made the carbon cloth highly hydrophilic and did not introduce any observable cracks or flaws. MFCs configured with APPJ-treated carbon cloth electrodes exhibited electrochemical performance (maximum power density of 7.56 mW m-2) superior to that of MFCs configured with untreated carbon cloth electrodes (maximum power density of 2.38 mW m-2). This boost in performance can be attributed to the formation of abundant carboxyl and ammonium functional groups on the surface of APPJ-treated carbon cloth, which promoted the formation of anodic biofilms and the adhesion of bacteria, while facilitating the transfer of electrons from the bacteria to the electrodes. APPJ surface modification is non-toxic and environmentally friendly (no exogenous chemicals are required), which is particularly beneficial as the introduction of toxins might otherwise inhibit bacterial growth and metabolism. The APPJ surface modification process is rapid, cost-effective, and applicable to substrates covering a large area, making it ideal for the fabrication of large-scale MFCs and bioelectrochemical bioenergy devices.

  5. Study of nanosecond discharges in different H2 air mixtures at atmospheric pressure for plasma-assisted applications

    Science.gov (United States)

    Bourdon, Anne; Kobayashi, Sumire; Bonaventura, Zdenek; Tholin, Fabien; Popov, Nikolay

    2016-09-01

    This paper presents 2D simulations of nanosecond pulsed discharges between two point electrodes in different H2/air mixtures and in air at atmospheric pressure. A fluid model is coupled with detailed kinetic schemes for air and different H2/air mixtures to simulate the discharge dynamics. First, as the positive and negative ionization waves propagate in the interelectrode gap, it has been observed that in H2/air mixtures with equivalence ratios between 0.3 and 2, major positive ions produced by the nanosecond discharge are N2+,O2+and HN2+.The discharge dynamics is shown to vary only slightly for equivalence ratios of the H2/air mixture between 0.3 and 2. Then, as the discharge transits to a nanosecond spark discharge, we have studied the different chemical reactions that lead to fast gas heating and to the production of radicals, as O,H and OH. Both thermal and chemical effects of the nanosecond spark discharge are of interest for plasma assisted combustion applications. This work has been supported by the project DRACO (Grant No. ANR-13-IS09-0004) and the french russian LIA Kappa.

  6. Photoemission study of fluorination atmospheric pressure plasma processes on EPDM: Influence of the carrier and fluorinating gas

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, L., E-mail: lidia.martinez@icmm.csic.es [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC) Cantoblanco, 28049 Madrid (Spain); Huttel, Y. [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC) Cantoblanco, 28049 Madrid (Spain); Verheyde, B.; Vanhulsel, A. [Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Roman, E. [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC) Cantoblanco, 28049 Madrid (Spain)

    2010-11-15

    Fluorination plasma treatments at atmospheric pressure were used to modify the surface composition of EPDM elastomer. In this study, two different precursors (CF{sub 4} and SF{sub 6}) and two carrier gases (He and Ar) were used for the surface modification of EPDM elastomer. The surface modifications were studied by means of X-ray photoelectron spectroscopy. We have observed a strong influence of the gas selection on the extent of the surface modification induced with these treatments. In general terms, the use of CF{sub 4} generates a higher concentration of fluorine in the elastomer surface. On the other hand, the use of He as carrier gas also increases the effectiveness of the modification process. The fluorine uptake varies between 2 and 13%, although the formation of fluorine-containing functional groups was detected when the amount of fluorine on the surface exceeded 7%. After all treatments, an important oxygen uptake was observed, with amounts three or four times higher than the untreated elastomer.

  7. The effect of three different methods of adding O2 additive on O concentration of atmospheric pressure plasma jets (APPJs)

    Science.gov (United States)

    Yue, Y.; Xian, Y.; Pei, X.; Lu, X.

    2016-12-01

    In order to maximize the O concentration generated by the atmospheric pressure plasma jets (APPJs), several different methods of adding O2 additive to working gas have been proposed. However, it is not clear, which method is capable of generating the highest concentration of O atom. In this paper, the concentration of O atoms in an APPJs by adding O2 to (1) the working gas, to (2) the downstream inside the tube, and (3) to the shielding gas is investigated by two-photon absorption laser-induced fluorescence spectrometry. The results clearly demonstrate that the highest O density is achieved when 1.5% of O2 is added to the working gas rather than the other two methods. In other words, the most effective way to generate O atoms is by premixing O2 with the working gas. Further investigation suggests that O atoms are mainly generated around the electrode region, where the electric field is highest. In addition, when O2 is added to the working gas, if in the meantime extra O2 is added to the downstream inside the tube, a significant decrease of O density is observed.

  8. Rapid atmospheric pressure plasma jet processed reduced graphene oxide counter electrodes for dye-sensitized solar cells.

    Science.gov (United States)

    Liu, Hsiao-Wei; Liang, Sheng-Ping; Wu, Ting-Jui; Chang, Haoming; Kao, Peng-Kai; Hsu, Cheng-Che; Chen, Jian-Zhang; Chou, Pi-Tai; Cheng, I-Chun

    2014-09-10

    In this work, we present the use of reduced graphene oxide (rGO) as the counter electrode materials in dye-sensitized solar cells (DSSCs). rGO was first deposited on a fluorine-doped tin oxide glass substrate by screen-printing, followed by post-treatment to remove excessive organic additives. We investigated the effect of atmospheric pressure plasma jet (APPJ) treatment on the DSSC performance. A power conversion efficiency of 5.19% was reached when DSSCs with an rGO counter electrode were treated by APPJs in the ambient air for a few seconds. For comparison, it requires a conventional calcination process at 400 °C for 15 min to obtain comparable efficiency. Scanning electron micrographs show that the APPJ treatment modifies the rGO structure, which may reduce its conductivity in part but simultaneously greatly enhances its catalytic activity. Combined with the rapid removal of organic additives by the highly reactive APPJ, DSSCs with APPJ-treated rGO counter electrode show comparable efficiencies to furnace-calcined rGO counter electrodes with greatly reduced process time. This ultrashort process time renders an estimated energy consumption per unit area of 1.1 kJ/cm(2), which is only one-third of that consumed in a conventional furnace calcination process. This new methodology thus saves energy, cost, and time, which is greatly beneficial to future mass production.

  9. Comparison of two electro-hydrodynamic force models for the interaction between helium jet flow and an atmospheric-pressure "plasma jet"

    Science.gov (United States)

    Logothetis, D.; Papadopoulos, P. K.; Svarnas, P.; Vafeas, P.

    2016-12-01

    In this work, two simple phenomenological models of the electro-hydrodynamic force that arises in an atmospheric-pressure "plasma jet" are presented. The models are distinguished by the different boundary conditions applied for the consideration of the plasma propagation length. The comparison is based on numerical simulations, which are combined with experimental data, in order to determine the magnitude of the electro-hydrodynamic force and assess the ability of the two models to evaluate the visible plasma length. The results reveal that the gas flow characteristics depend on the spatial range of the force action and the force magnitude, and vice versa.

  10. Atmospheric pressure plasma chemical vapor deposition reactor for 100 mm wafers, optimized for minimum contamination at low gas flow rates

    Energy Technology Data Exchange (ETDEWEB)

    Anand, Venu, E-mail: venuanand@cense.iisc.ernet.in, E-mail: venuanand83@gmail.com; Shivashankar, S. A. [Centre for Nano Science and Engineering (CeNSE), Indian Institute of Science (IISc), Bangalore 560012 (India); Nair, Aswathi R.; Mohan Rao, G. [Department of Instrumentation and Applied Physics (IAP), Indian Institute of Science (IISc), Bangalore 560012 (India)

    2015-08-31

    Gas discharge plasmas used for thinfilm deposition by plasma-enhanced chemical vapor deposition (PECVD) must be devoid of contaminants, like dust or active species which disturb the intended chemical reaction. In atmospheric pressure plasma systems employing an inert gas, the main source of such contamination is the residual air inside the system. To enable the construction of an atmospheric pressure plasma (APP) system with minimal contamination, we have carried out fluid dynamic simulation of the APP chamber into which an inert gas is injected at different mass flow rates. On the basis of the simulation results, we have designed and built a simple, scaled APP system, which is capable of holding a 100 mm substrate wafer, so that the presence of air (contamination) in the APP chamber is minimized with as low a flow rate of argon as possible. This is examined systematically by examining optical emission from the plasma as a function of inert gas flow rate. It is found that optical emission from the plasma shows the presence of atmospheric air, if the inlet argon flow rate is lowered below 300 sccm. That there is minimal contamination of the APP reactor built here, was verified by conducting an atmospheric pressure PECVD process under acetylene flow, combined with argon flow at 100 sccm and 500 sccm. The deposition of a polymer coating is confirmed by infrared spectroscopy. X-ray photoelectron spectroscopy shows that the polymer coating contains only 5% of oxygen, which is comparable to the oxygen content in polymer deposits obtained in low-pressure PECVD systems.

  11. Atmospheric pressure plasma produced inside a closed package by a dielectric barrier discharge in Ar/CO2 for bacterial inactivation of biological samples

    DEFF Research Database (Denmark)

    Chiper, Alina Silvia; Chen, Weifeng; Mejlholm, Ole

    2011-01-01

    The generation and evaluation of a dielectric barrier discharge produced inside a closed package made of a commercially available packaging film and filled with gas mixtures of Ar/CO2 at atmospheric pressure is reported. The discharge parameters were analysed by electrical measurements and optical...... emission spectroscopy in two modes of operation: trapped gas atmosphere and flowing gas atmosphere. Gas temperature was estimated using the OH(A–X) emission spectrum and the rotational temperature reached a saturation level after a few minutes of plasma running. The rotational temperature was almost three...

  12. Optical diagnostics and mass spectrometry on the afterglow of an atmospheric pressure Ar/O$_2$ radiofrequency plasma used for polymer surface treatment

    CERN Document Server

    Duluard, Corinne Y; Hubert, Julie; Reniers, François

    2016-01-01

    In the context of polymer surface treatment, the afterglow of an atmospheric pressure Ar/O$_2$ radiofrequency plasma is characterized by optical emission spectroscopy, laser induced fluorescence and mass spectrometry. The influence of the O$_2$ gas flow rate and the source power on the plasma properties (gas temperature, Ar excitation temperature, relative concentrations of O atoms and OH radicals) are evaluated. We show that for plasma torch-to-substrate distances lower than 6 mm, the afterglow creates a protective atmosphere, thus the plasma gas composition interacting with the substrate is well controlled. For higher distances, the influence of ambient air can no longer be neglected and gradients in Ar, O$_2$ and N$_2$ concentrations are measured as a function of axial and vertical position.

  13. Improving the low temperature dyeability of polyethylene terephthalate fabric with dispersive dyes by atmospheric pressure plasma discharge

    Science.gov (United States)

    Elabid, Amel E. A.; Zhang, Jie; Shi, Jianjun; Guo, Ying; Ding, Ke; Zhang, Jing

    2016-07-01

    Polyethylene terephthalate (PET) fiber and textile is one of the largest synthetic polymer commodity in the world. The great energy consumption and pollution caused by the high temperature and pressure dyeing of PET fibers and fabrics with disperse dyes has been caused concern these years. In this study, an atmospheric pressure plasma with fine and uniform filament discharge operated at 20 kHz has been used to improve the low temperature dyeability of PET fabric at 95 °C with three cation disperse dyes: Red 73, Blue 183 and Yellow 211. The dyes uptake percentage of the treated PET fabrics was observed to increase as twice as much of untreated fabric. The color strength rate was increased more than 20%. The reducing of the water contact angle and the raising of the capillary height of treated PET fabric strip indicate its hydrophilicity improvement. Scanning electron microscope (SEM) results display nano to micro size of etching pits appeared uniformly on the fiber surface of the treated PET. Simultaneously, X-ray photoelectron spectroscopy (XPS) analysis indicates an increase of the oxygen content in the surface caused by the introduction of polar groups such as Cdbnd O and COOH. The rough surface with improved polar oxygen groups showed hydrophilicity and affinity to C.I. dispersive dyes and is believed to be caused by the strong and very fine filament discharge appearing randomly at one place at an instant but evenly at many places at a longer period. This increases the diffusion and absorption of the C.I. disperse dyes on the PET fiber surface, which improve its low temperature dyeability.

  14. Influences of guide-tube and bluff-body on advanced atmospheric pressure plasma source for single-crystalline polymer nanoparticle synthesis at low temperature

    Science.gov (United States)

    Kim, Dong Ha; Park, Choon-Sang; Kim, Won Hyun; Shin, Bhum Jae; Hong, Jung Goo; Park, Tae Seon; Seo, Jeong Hyun; Tae, Heung-Sik

    2017-02-01

    The use of a guide-tube and bluff-body with an advanced atmospheric pressure plasma source is investigated for the low-temperature synthesis of single-crystalline high-density plasma polymerized pyrrole (pPPy) nano-materials on glass and flexible substrates. Three process parameters, including the position of the bluff-body, Ar gas flow rate, and remoteness of the substrate from the intense and broadened plasma, are varied and examined in detail. Plus, for an in-depth understanding of the flow structure development with the guide-tube and bluff-body, various numerical simulations are also conducted using the same geometric conditions as the experiments. As a result, depending on both the position of the bluff-body and the Ar gas flow rate, an intense and broadened plasma as a glow-like discharge was produced in a large area. The production of the glow-like discharge played a significant role in increasing the plasma energy required for full cracking of the monomers in the nucleation region. Furthermore, a remote growth condition was another critical process parameter for minimizing the etching and thermal damage during the plasma polymerization, resulting in single- and poly-crystalline pPPy nanoparticles at a low temperature with the proposed atmospheric pressure plasma jet device.

  15. Antibacterial Activity of Cold Atmospheric Pressure Argon Plasma against 78 Genetically Different (mecA, luk-P, agr or Capsular Polysaccharide Type) Staphylococcus aureus Strains.

    Science.gov (United States)

    Matthes, Rutger; Lührman, Anne; Holtfreter, Silva; Kolata, Julia; Radke, Dörte; Hübner, Nils-Olaf; Assadian, Ojan; Kramer, Axel

    2016-01-01

    Previous studies on the antimicrobial activity of cold atmospheric pressure argon plasma showed varying effects against mecA+ or mecA-Staphylococcus aureus strains. This observation may have important clinical and epidemiological implications. Here, the antibacterial activity of argon plasma was investigated against 78 genetically different S. aureus strains, stratified by mecA, luk-P, agr1-4, or the cell wall capsule polysaccharide types 5 and 8. kINPen09® served as the plasma source for all experiments. On agar plates, mecA+luk-P-S. aureus strains showed a decreased susceptibility against plasma compared to other S. aureus strains. This study underlines the high complexity of microbial defence against antimicrobial treatment and confirms a previously reported strain-dependent susceptibility of S. aureus to plasma treatment.

  16. Repeated applications of cold atmospheric pressure plasma does not induce resistance in Staphylococcus aureus embedded in biofilms

    Directory of Open Access Journals (Sweden)

    Matthes, Rutger

    2014-09-01

    Full Text Available [english] Introduction: The increasing microbial resistance against antibiotics complicates the therapy of bacterial infections. Therefore new therapeutic options, particularly those causing no resistance, are of high interest. Cold atmospheric plasma is one possible option to eradicate multidrug resistant microorganisms, and so far no resistance development against physical plasma is known.Method: We tested 6-fold repeated plasma applications on a strain embedded in biofilm and compared the reduction of the colony forming units between the different treatment periods to asses a possible development of resistance.Result: For all treatment periods, the control biofilms were reduced by plasma in average by 1.7 log CFU, and decreased from 7.6 to 5.8 log (CFU/cm within 5 hours. The results demonstrated that repeated plasma doses not induce resistance or habituation against plasma applied within short time periods.Conclusion: The repeated application of cold plasma is a promising option for the treatment of infected wounds without the risk of development of resistance against plasma.

  17. Application of post-discharge region of atmospheric pressure argon and air plasma jet in the contamination control of Candida albicans biofilms

    Directory of Open Access Journals (Sweden)

    Anelise Cristina Osório Cesar Doria

    Full Text Available Introduction:Candida species are responsible for about 80% of hospital fungal infections. Non-thermal plasmas operated at atmospheric pressure are increasingly used as an alternative to existing antimicrobial strategy. This work investigates the action of post-discharge region of a non-thermal atmospheric plasma jet, generated by a gliding arc reactor, on biofilms of standard strain of Candida albicans grown on polyurethane substrate. Methods Samples were divided into three groups: (i non-treated; (ii treated with argon plasma, and (iii treated with argon plus air plasma. Subsequently to plasma treatment, counting of colony-forming units (CFU/ml and cell viability tests were performed. In addition, the surface morphology of the samples was evaluated by scanning electron microscopy (SEM and optical profilometry (OP. Results Reduction in CFU/ml of 85% and 88.1% were observed in groups ii and iii, respectively. Cell viability after treatment also showed reduction of 33% in group ii and 8% in group iii, in comparison with group i (100%. The SEM images allow observation of the effect of plasma chemistry on biofilm structure, and OP images showed a reduction of its surface roughness, which suggests a possible loss of biofilm mass. Conclusion The treatment in post-discharge region and the chemistries of plasma jet tested in this work were effective in controlling Candida albicans biofilm contamination. Finally, it was evidenced that argon plus air plasma was the most efficient to reduce cell viability.

  18. Effects of the electrical excitation signal parameters on the geometry of an argon-based non-thermal atmospheric pressure plasma jet.

    Science.gov (United States)

    Benabbas, Mohamed Tahar; Sahli, Salah; Benhamouda, Abdallah; Rebiai, Saida

    2014-12-01

    A non-thermal atmospheric pressure argon plasma jet for medical applications has been generated using a high-voltage pulse generator and a homemade dielectric barrier discharge (DBD) reactor with a cylindrical configuration. A plasma jet of about 6 cm of length has been created in argon gas at atmospheric pressure with an applied peak to peak voltage and a frequency of 10 kV and 50 kHz, respectively. The length and the shape of the created plasma jet were found to be strongly dependent on the electrode setup and the applied voltage and the signal frequency values. The length of the plasma jet increases when the applied voltage and/or its frequency increase, while the diameter at its end is significantly reduced when the applied signal frequency increases. For an applied voltage of 10 kV, the plasma jet diameter decreases from near 5 mm for a frequency of 10 kHz to less than 1 mm at a frequency of 50 kHz. This obtained size of the plasma jet diameter is very useful when the medical treatment must be processed in a reduced space. PACS 2008: 52.50.Dg; 52.70.-m; 52.80.-s.

  19. Functionalization of nanomaterials by non-thermal large area atmospheric pressure plasmas: application to flexible dye-sensitized solar cells

    Science.gov (United States)

    Jung, Heesoo; Park, Jaeyoung; Yoo, Eun Sang; Han, Gill-Sang; Jung, Hyun Suk; Ko, Min Jae; Park, Sanghoo; Choe, Wonho

    2013-08-01

    A key challenge to the industrial application of nanotechnology is the development of