scholarly journals Transport of Gaseous Hydrogen Peroxide and Ozone into Bulk Water vs. Electrosprayed Aerosol

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 182
Author(s):  
Mostafa Elsayed Hassan ◽  
Mário Janda ◽  
Zdenko Machala
Keyword(s):  
Hydrogen Peroxide ◽  
Gas Flow ◽  
Treatment Time ◽  
Water Flow Rate ◽  
Total Surface Area ◽  
Bulk Water ◽  
Experimental Investigations ◽  
Transport Mechanisms ◽  
Air Plasma ◽  
Plasma Species

Production and transport of reactive species through plasma–liquid interactions play a significant role in multiple applications in biomedicine, environment, and agriculture. Experimental investigations of the transport mechanisms of typical air plasma species: hydrogen peroxide (H2O2) and ozone (O3) into water are presented. Solvation of gaseous H2O2 and O3 from an airflow into water bulk vs. electrosprayed microdroplets was measured, while changing the water flow rate and applied voltage, during different treatment times and gas flow rates. The solvation rate of H2O2 and O3 increased with the treatment time and the gas–liquid interface area. The total surface area of the electrosprayed microdroplets was larger than that of the bulk, but their lifetime was much shorter. We estimated that only microdroplets with diameters below ~40 µm could achieve the saturation by O3 during their lifetime, while the saturation by H2O2 was unreachable due to its depletion from air. In addition to the short-lived flying microdroplets, the longer-lived bottom microdroplets substantially contributed to H2O2 and O3 solvation in water electrospray. This study contributes to a better understanding of the gaseous H2O2 and O3 transport into water and will lead to design optimization of the water spray and plasma-liquid interaction systems.

scholarly journals Transport of Gaseous Hydrogen Peroxide and Ozone into Bulk Water vs. Electrosprayed Aerosol

2020 ◽  
Author(s):  
Mostafa Elsayed Hassan ◽  
Mario Janda ◽  
Zdenko Machala
Keyword(s):  
Hydrogen Peroxide ◽  
Treatment Time ◽  
Total Surface Area ◽  
Bulk Water ◽  
Liquid Interface ◽  
Gaseous Hydrogen ◽  
Transport Mechanisms ◽  
Interface Area ◽  
Flow Rates ◽  
Plasma Species

Production and transport of reactive species through plasma-liquid interactions plays a significant role in multiple applications in biomedicine, environment, and agriculture. We experimentally investigated the transport mechanisms of hydrogen peroxide H2O2 and ozone O3, as the typical plasma species, into water. We measured the solvation of gaseous H2O2 and O3 in airflow into water bulk vs. electrosprayed microdroplets while changing the gas and water flow rates, applied voltage that determines the gas-liquid interface area, and treatment time. The solvation rate of H2O2 and O3 increased with the treatment time and the gas-liquid interface area. The total surface area of the electrosprayed microdroplets was larger than that of the bulk, but their lifetime was much shorter. We estimated that only microdroplets with diameters below ~ 40 µm could achieve the saturation by O3 during their lifetime, while the saturation by H2O2 was impossible due to its depletion from air. Besides the short-lived flying microdroplets, the longer-lived bottom microdroplets substantially contributed to H2O2 and O3 solvation in water electrospray. This study contributes to a better understanding of the gaseous H2O2 and O3 transport into water as a function of different parameters and will lead to design optimization of the plasma-liquid interaction systems.

scholarly journals Differential Influence of Components Resulting from Atmospheric-Pressure Plasma on Integrin Expression of Human HaCaT Keratinocytes

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Beate Haertel ◽  
Susanne Straßenburg ◽  
Katrin Oehmigen ◽  
Kristian Wende ◽  
Thomas von Woedtke ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Wound Healing ◽  
Atmospheric Pressure ◽  
Treatment Time ◽  
Atmospheric Pressure Plasma ◽  
Integrin Expression ◽  
Hacat Keratinocytes ◽  
Air Plasma ◽  
Pressure Plasma ◽  
Intracellular Ros

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.

scholarly journals Heterogeneous Bonding of PMMA and Double-Sided Polished Silicon Wafers through H2O Plasma Treatment for Microfluidic Devices

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 580
Author(s):  
Chao-Ching Chiang ◽  
Philip Nathaniel Immanuel ◽  
Yi-Hsiung Chiu ◽  
Song-Jeng Huang
Keyword(s):  
Plasma Treatment ◽  
Flow Rate ◽  
Gas Flow ◽  
Treatment Time ◽  
Optical Emission ◽  
Microfluidic Devices ◽  
Oh Radicals ◽  
Gas Flow Rate ◽  
Oh Groups ◽  
Plasma Treatment Time

In this work we report on a rapid, easy-to-operate, lossless, room temperature heterogeneous H2O plasma treatment process for the bonding of poly(methyl methacrylate) (PMMA) and double-sided polished (DSP) silicon substrates by for utilization in sandwich structured microfluidic devices. The heterogeneous bonding of the sandwich structure produced by the H2O plasma is analyzed, and the effect of heterogeneous bonding of free radicals and high charge electrons (e−) in the formed plasma which causes a passivation phenomenon during the bonding process investigated. The PMMA and silicon surface treatments were performed at a constant radio frequency (RF) power and H2O flow rate. Changing plasma treatment time and powers for both processes were investigated during the experiments. The gas flow rate was controlled to cause ionization of plasma and the dissociation of water vapor from hydrogen (H) atoms and hydroxyl (OH) bonds, as confirmed by optical emission spectroscopy (OES). The OES results show the relative intensity peaks emitted by the OH radicals, H and oxygen (O). The free energy is proportional to the plasma treatment power and gas flow rate with H bonds forming between the adsorbed H2O and OH groups. The gas density generated saturated bonds at the interface, and the discharge energy that strengthened the OH-e− bonds. This method provides an ideal heterogeneous bonding technique which can be used to manufacture new types of microfluidic devices.

Experimental Inverstigations On the Pressure Fluctuations in the Sealing Gap of Dry Gas Seals with Embedded Pressure Sensors

2021 ◽  
Author(s):  
Jingjing Luo ◽  
Dieter Brillert
Keyword(s):  
High Speed ◽  
Gas Flow ◽  
Static Pressure ◽  
Pressure Sensors ◽  
Operating Conditions ◽  
Test Facility ◽  
Experimental Investigations ◽  
Mechanical Seals ◽  
Process Gas ◽  
Sealing Gap

Abstract Dry gas lubricated non-contacting mechanical seals (DGS), most commonly found in centrifugal compressors, prevent the process gas flow into the atmosphere. Especially when high speed is combined with high pressure, DGS is the preferred choice over other sealing alternatives. In order to investigate the flow field in the sealing gap and to facilitate the numerical prediction of the seal performance, a dedicated test facility is developed to carry out the measurement of key parameters in the gas film. Gas in the sealing film varies according to the seal inlet pressure, and the thickness of gas film depends on this fluctuated pressure. In this paper, the test facility, measurement methods and the first results of static pressure measurements in the sealing gap of the DGS obtained in the described test facility are presented. An industry DGS with three-dimensional grooves on the surface of the rotating ring, where experimental investigations take place, is used. The static pressure in the gas film is measured, up to 20 bar and 8,100 rpm, by several high frequency ultraminiature pressure transducers embedded into the stationary ring. The experimental results are discussed and compared with the numerical model programmed in MATLAB, the characteristic and magnitude of which have a good agreement with the numerical simulations. It suggests the feasibility of measuring pressure profiles of the standard industry DGS under pressurized dynamic operating conditions without altering the key components of the seal and thereby affecting the seal performance.

scholarly journals Experimental investigations of CO2 seepage behaviorin naturally fractured coal under hydro-thermal-mechanical conditions

2021 ◽  
Vol 25 (6 Part B) ◽  
pp. 4651-4658
Author(s):  
Teng Teng ◽  
Xiaoyan Zhu ◽  
Yu-Ming Wang ◽  
Chao-Yang Ren
Keyword(s):  
Gas Flow ◽  
Confining Pressure ◽  
Gas Pressure ◽  
Experimental Investigations ◽  
Permeability Evolution ◽  
Coal Permeability ◽  
Naturally Fractured ◽  
Series Of Experiments ◽  
Fractured Coal ◽  
Increasing Temperature

Gas-flow in coal or rock is hypersensitive to the changes of temperature, confin?ing pressure and gas pressure. This paper implemented a series of experiments to observe the seepage behavior, especially the permeability evolution of CO2 in naturally fractured coal sample under coupled hydro-thermal-mechanical conditions. The experimental results show that coal permeability increases exponentially with the increasing gas pressure, and tends to be linear when the confining pressure is high. Coal permeability decreases exponentially with the increasing confining pressure. Coal permeability decreases with the increasing temperature generally, but it may bounce up when the temperature rises to high. The results provide reference for the projects of coal gas extraction and carbon dioxide geological sequestration.

An Investigation of Particle Injection and Resulting In-Flight Particle Behavior During Air Plasma Spraying

2006 ◽  
Author(s):  
W. Zhang ◽  
V. Srinivasan ◽  
L. L. Zheng ◽  
S. Sampath
Keyword(s):  
Gas Flow ◽  
Process Parameter ◽  
Diagnostic Tools ◽  
Particle State ◽  
Plasma Diagnostic ◽  
Air Plasma ◽  
Particle Injection ◽  
Carrier Gas ◽  
Particle Behavior ◽  
Particle Characteristics

In this article we present our studies on the role of particle injection on the in-flight particle characteristics in an external orthogonally injected air plasma spray system. The influence of carrier gas on the in-flight particle state has been investigated, experimentally and using simulation, for Yttria Stabilized Zirconia (YSZ) thermal spray powder processed in an Ar-H2 plasma. Diagnostic tools such as IPP and SPT have been used to measure the plume characteristics and ensemble temperature while DPV-2000 has been used to measure the distributions of individual particle characteristics such as temperature, velocity and size, at the point of the maximum particle flux and at various points (square grid) in the plume cross-section. Three-dimensional simulations have been performed for the cases presented in the experiments. Specifically, the effects of carrier gas flow rate on the in-flight particle characteristics were studied at multiple stand-off distances. Simulation results agree well with the experimental observation that the particle velocity and temperature will increase with the plume angle and then decrease after reaching a maxima for a given process parameter combination and stand-off distance. This maxima has been observed at the same plume angle for different process parameter combinations. The results of this study are currently being used to 'optimize' the particle injection and trajectory, which enables better understanding of the influence of plasma forming and stabilizing parameters (gas flows and arc current) on the in-flight particle behavior.

scholarly journals Development of a Laboratory-Scale Thermal-Arc-Plasma Reactor and its Application in the Pyrolysis of Petroleum Oily Sludge

2020 ◽  
Vol 2 (1) ◽  
pp. 15-27
Author(s):  
Abubakar M. Ali ◽  
Mohd A. Abu-Hassan ◽  
Raja R.K. Ibrahim ◽  
Bala I. Abdulkarim
Keyword(s):  
Flue Gas ◽  
Gas Flow ◽  
Waste Treatment ◽  
Treatment Time ◽  
Plasma Reactor ◽  
Pilot Scale ◽  
Oily Sludge ◽  
Arc Plasma ◽  
Plasma Arc ◽  
Mass Reduction

Waste treatment using thermal arc plasma is well established and laboratory/pilot scale plasma reactors were developed and their performances for the destruction of different hazardous wastes, other than petroleum oily sludge, were studied. This work aims to extend the plasma technology to the pyrolysis of hazardous petroleum oily sludge. A 4.7 kW thermal arc plasma reactor was developed using a standard TIG arc welding torch. The transferred arc plasma reactor was used to treat 20 g/batch of petroleum oily sludge. The prevailing temperature inside the reactor ranges between 356 – 1694 oC. The plasma arc temperature increased with increasing plasma arc current and also with increasing plasma gas flow-rate. A vitreous slag and a flue gas were generated as products. A mass reduction of between 36.87 – 91.40% and a TOC reduction of 21.47 – 93.76% were achieved in the treatment time of 2 – 5 min. The mass reduction was observed to increase with treatment time. However, the increase was more rapid between the 3rd and the 4th min of the treatment. The flue gas produced contains H2 (43.79 – 50.97 mol%), H2O (26.60 – 30.22 mol%), CO (8.45 – 11.18 mol%), CO2 (5.12 – 10.35 mol%), CH4 (2.17 – 3.38 mol%), C2H2 (0.86 – 2.69 mol%) and C2H4 (0.76 – 2.17 mol%). Thus, the thermal plasma reactor provides a suitable method of treating petroleum oily sludge.

scholarly journals Surface Functionalization of a Polyurethane Surface via Radio-Frequency Cold Plasma Treatment Using Different Gases

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1067 ◽  
Author(s):  
Aya E. Abusrafa ◽  
Salma Habib ◽  
Anton Popelka
Keyword(s):  
Plasma Treatment ◽  
Treatment Time ◽  
Polymer Surface ◽  
Peel Test ◽  
Maximum Plasma ◽  
Air Plasma ◽  
Temperature Plasma ◽  
Aging Study ◽  
Roughness Analysis ◽  
Gaseous Media

Herein, the surface treatment of polyurethane (PU) films via air, O2, N2, Ar, and their mixtures were tested. The treatment was performed to incorporate new polar functionalities on the polymer surface and achieve improved hydrophilic characteristics. The PU films were subjected to RF low-temperature plasma treatment. It was found that plasma treatment immensely enhanced the hydrophilic surface properties of the PU films in comparison with those of the pristine samples; the maximum plasma effect occurred for the PU sample in the presence of air plasma with treatment time of 180 s at nominal power of 80 W. The surface topography was also found to vary with plasma exposure time and the type of gas being used due to the reactivity of the gaseous media. Roughness analysis revealed that at higher treatment times, the etching/degradation of the surface became more pronounced. Surface chemistry studies revealed increased O2 and N2 elemental groups on the surface upon exposure to O2, N2, air, and Ar. Additionally, the aging study revealed that samples treated in the presence of air and Ar were more stable in comparison to those of the other gases for both the contact angle and peel test measurements.

scholarly journals Parameters Affecting the Antimicrobial Properties of Cold Atmospheric Plasma Jet

2019 ◽  
Vol 8 (11) ◽  
pp. 1930 ◽  
Author(s):  
Bih-Show Lou ◽  
Chih-Ho Lai ◽  
Teng-Ping Chu ◽  
Jang-Hsing Hsieh ◽  
Chun-Ming Chen ◽  
...  
Keyword(s):  
Gas Flow ◽  
Treatment Time ◽  
Plasma Jet ◽  
Atmospheric Plasma ◽  
Gas Flow Rate ◽  
Cold Atmospheric Plasma ◽  
E Coli ◽  
Antimicrobial Efficiency ◽  
Ar Gas ◽  
Sample Distance

Using the Taguchi method to narrow experimental parameters, the antimicrobial efficiency of a cold atmospheric plasma jet (CAPJ) treatment was investigated. An L9 array with four parameters of CAPJ treatments, including the application voltage, CAPJ-sample distance, argon (Ar) gas flow rate, and CAPJ treatment time, were applied to examine the antimicrobial activity against Escherichia coli (E. coli). CAPJ treatment time was found to be the most influential parameter in its antimicrobial ability by evaluation of signal to noise ratios and analysis of variance. 100% bactericidal activity was achieved under the optimal bactericidal activity parameters including the application voltage of 8.5 kV, CAPJ-sample distance of 10 mm, Ar gas flow rate of 500 sccm, and CAPJ treatment time of 300 s, which confirms the efficacy of the Taguchi method in this design. In terms of the mechanism of CAPJ’s antimicrobial ability, the intensity of hydroxyl radical produced by CAPJ positively correlated to its antimicrobial efficiency. The CAPJ antimicrobial efficiency was further evaluated by both DNA double-strand breaks analysis and scanning electron microscopy examination of CAPJ treated bacteria. CAPJ destroyed the cell wall of E. coli and further damaged its DNA structure, thus leading to successful killing of bacteria. This study suggests that optimal conditions of CPAJ can provide effective antimicrobial activity and may be grounds for a novel approach for eradicating bacterial infections.

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