scholarly journals A new type of non-thermal atmospheric pressure plasma source based on a waveguide bridge

2021 ◽  
Vol 2064 (1) ◽  
pp. 012131
Author(s):  
V N Tikhonov ◽  
S A Gorbatov ◽  
I A Ivanov ◽  
A V Tikhonov
Keyword(s):  
Atmospheric Pressure ◽  
Microwave Plasma ◽  
Short Circuit ◽  
Atmospheric Pressure Plasma ◽  
Plasma Source ◽  
Gas Temperature ◽  
Matched Load ◽  
Microwave Source ◽  
New Type ◽  
Complexity Cost

Abstract A new type of microwave source of non-thermal atmospheric pressure plasmas, presented earlier by the authors, has both the characteristics of a dielectric barrier discharge (in terms of the configuration and low gas temperature) and an ability to form a “clean” plasma jet like a classical microwave plasma torch. However, the need to use a circulator leads to a significant increase in complexity, cost and weight of the installation as a whole. The basis of the presented plasma source is a three-decibel waveguide bridge with connection through a narrow wall. Both output arms of the bridge are loaded on identical short-circuited segments of waveguides. The discharge tube passes across the waveguides at a distance of a quarter of the wavelength from the short circuit. Since the output arms of the bridge are always loaded symmetrically, the generator’s power which is reflected from the short circuits or not be absorbed in the microwave discharge, enters the decoupled arm of the bridge that is connected to the matched load. Thus, the magnetron is protected from the reflected wave without the need for an expensive circulator, in any case.

scholarly journals A New Stripline-Based Atmospheric Pressure Microwave Plasma Sheet Source Designed for Surface Modification of Materials

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7212
Author(s):  
Helena Nowakowska ◽  
Dariusz Czylkowski ◽  
Bartosz Hrycak ◽  
Mariusz Jasiński
Keyword(s):  
Surface Modification ◽  
Atmospheric Pressure ◽  
Microwave Plasma ◽  
Coaxial Line ◽  
Plasma Source ◽  
Power Flux ◽  
Power Characteristics ◽  
Radiated Power ◽  
New Type ◽  
The Difference

A new type of microwave plasma source is presented in which plasma at atmospheric pressure is generated inside a quartz rectangular flat box placed in a stripline supplied by a 2.45 GHz coaxial line. The plasma has a sheet shape and is designed for surface modification. Electric field and power flux distributions, tuning characteristics, and power characteristics (ratios of radiated, absorbed, and entering power) are numerically studied for three configurations: open, semi-closed, and closed. The calculations show that near-zero radiation reduction is possible only for the closed configuration, while the ratio of radiated power to entering power is always greater than 30% for the other configurations. The moving plunger is not sufficient for the ratio of reflected to incident power to fall below 20% for both the closed and open configurations. This is possible for the semi-closed configuration, but then the radiated power is the highest. The experiment shows that for the same entering power, the plasma volume is largest for the closed configuration and smallest for the open configuration, which we attribute to the difference in radiated power. The plasma generated using the closed stripline configuration has a larger volume than plasma generated using the rectangular waveguide.

scholarly journals Plasma-Treated Air and Water—Assessment of Synergistic Antimicrobial Effects for Sanitation of Food Processing Surfaces and Environment

Foods ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 55 ◽  
Author(s):  
Uta Schnabel ◽  
Oliver Handorf ◽  
Kateryna Yarova ◽  
Björn Zessin ◽  
Susann Zechlin ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Microwave Plasma ◽  
Treatment Time ◽  
Synergistic Effects ◽  
Atmospheric Pressure Plasma ◽  
Plasma Source ◽  
Reduction Factor ◽  
Treated Water ◽  
Antimicrobial Effects ◽  
Proliferation Assays

The synergistic antimicrobial effects of plasma-processed air (PPA) and plasma-treated water (PTW), which are indirectly generated by a microwave-induced non-atmospheric pressure plasma, were investigated with the aid of proliferation assays. For this purpose, microorganisms (Listeria monocytogenes, Escherichia coli, Pectobacterium carotovorum, sporulated Bacillus atrophaeus) were cultivated as monocultures on specimens with polymeric surface structures. Both the distinct and synergistic antimicrobial potential of PPA and PTW were governed by the plasma-on time (5–50 s) and the treatment time of the specimens with PPA/PTW (1–5 min). In single PTW treatment of the bacteria, an elevation of the reduction factor with increasing treatment time could be observed (e.g., reduction factor of 2.4 to 3.0 for P. carotovorum). In comparison, the combination of PTW and subsequent PPA treatment leads to synergistic effects that are clearly not induced by longer treatment times. These findings have been valid for all bacteria (L. monocytogenes > P. carotovorum = E. coli). Controversially, the effect is reversed for endospores of B. atrophaeus. With pure PPA treatment, a strong inactivation at 50 s plasma-on time is detectable, whereas single PTW treatment shows no effect even with increasing treatment parameters. The use of synergistic effects of PTW for cleaning and PPA for drying shows a clear alternative for currently used sanitation methods in production plants. Highlights: Non-thermal atmospheric pressure microwave plasma source used indirect in two different modes—gaseous and liquid; Measurement of short and long-living nitrite and nitrate in corrosive gas PPA (plasma-processed air) and complex liquid PTW (plasma-treated water); Application of PTW and PPA in single and combined use for biological decontamination of different microorganisms.

scholarly journals Surface Modification of Polycarbonate by an Atmospheric Pressure Argon Microwave Plasma Sheet

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2418 ◽  
Author(s):  
Dariusz Czylkowski ◽  
Bartosz Hrycak ◽  
Andrzej Sikora ◽  
Magdalena Moczała-Dusanowska ◽  
Mirosław Dors ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Modification ◽  
Plasma Sheet ◽  
Microwave Power ◽  
Atmospheric Pressure ◽  
Microwave Plasma ◽  
Atmospheric Pressure Plasma ◽  
Plasma Source ◽  
Material Surface ◽  
Pressure Plasma

The specific properties of an atmospheric pressure plasma make it an attractive tool for the surface treatment of various materials. With this in mind, this paper presents the results of experimental investigations of a polycarbonate (PC) material surface modification using this new type of argon microwave (2.45 GHz) plasma source. The uniqueness of the new plasma source lies in the shape of the generated plasma—in contrast to other microwave plasma sources, which usually provide a plasma in the form of a flame or column, the new ones provides a plasma in the shape of a regular plasma sheet. The influence of the absorbed microwave power and the number of scans on the changes of the wettability and morphological and mechanical properties of the plasma-treated PC samples was investigated. The mechanical properties and changes in roughness of the samples were measured by the use of atomic force microscopy (AFM). The wettability of the plasma-modified samples was tested by measuring the water contact angle. In order to confirm the plasma effect, each of the above-mentioned measurements was performed before and after plasma treatment. All experimental tests were performed with an argon of flow rate up to 20 L/min and the absorbed microwave power ranged from 300 to 850 W. The results prove the capability of the new atmospheric pressure plasma type in modifying the morphological and mechanical properties of PC surfaces for industrial applications.

scholarly journals Merits of microwave plasmas for optical emission spectrometry – characterization of an axially viewed microwave-sustained, inductively coupled, atmospheric-pressure plasma (MICAP)

2020 ◽  
Vol 35 (10) ◽  
pp. 2369-2377
Author(s):  
Helmar Wiltsche ◽  
Matthias Wolfgang
Keyword(s):  
Atmospheric Pressure ◽  
Atmospheric Pressure Plasma ◽  
Optical Emission ◽  
Plasma Source ◽  
Optical Emission Spectrometry ◽  
Emission Spectrometry ◽  
Icp Oes ◽  
Microwave Plasmas ◽  
Inductively Coupled

The MICAP is a microwave driven plasma source employing nitrogen as the plasma gas. In this work we compare LODs and LOQs obtained in axial viewing with those obtained by ICP-OES and evaluate the effect of air instead of nitrogen as the plasma gas.

Development and Characterization of a Portable Atmospheric-Pressure Argon Plasma Jet for Sterilization

2015 ◽  
Author(s):  
Zhi-Hua Lin ◽  
Jong-Shinn Wu ◽  
Chen-Yon Tobias Tschang ◽  
Chi-Feng Su ◽  
Tuoh Wu ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Argon Plasma ◽  
Atmospheric Pressure Plasma ◽  
Plasma Jet ◽  
Gas Temperature ◽  
E Coli ◽  
Bacteria Inactivation ◽  
Argon Plasma Jet ◽  
Absorption Power

In this study, we would like to develop a portable round argon atmospheric-pressure plasma jet (APPJ) which can be applied for general use of bacteria inactivation. The APPJ was characterized electrically and optically, which include measurements of absorption power, gas temperature and optical properties of plasma generated species. Measured OH* number density at 5 mm downstream was estimated to be 5.8 × 1015 cm−3 and the electron density and electron temperature were estimated to be 2.4 × 1015 cm−3 and 0.34 eV, respectively, in the discharge region. This APPJ was demonstrated to effectively inactivate E. coli within seconds of treatment, which shows its great potential in the future use of general bacteria inactivation and sterilization.

scholarly journals Hydrogen production from ethanol in nitrogen microwave plasma at atmospheric pressure

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Bartosz Hrycak ◽  
Dariusz Czylkowski ◽  
Robert Miotk ◽  
Miroslaw Dors ◽  
Mariusz Jasinski ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Atmospheric Pressure ◽  
Alternative Energy ◽  
Coal Gasification ◽  
Microwave Plasma ◽  
Atmospheric Pressure Plasma ◽  
Water Electrolysis ◽  
Experimental Tests ◽  
Experimental Investigations ◽  
Promising Alternative

AbstractHydrogen seems to be one of the most promising alternative energy sources. It is a renewable fuel as it could be produced from e.g. waste or bio-ethanol. Furthermore hydrogen is compatible with fuel cells and is environmentally clean. In contrast to conventional methods of hydrogen production such as water electrolysis or coal gasification we propose a method based on atmospheric pressure microwave plasma. In this paper we present results of the experimental investigations of hydrogen production from ethanol in the atmospheric pressure plasma generated in waveguide-supplied cylindrical type nozzleless microwave (2.45 GHz) plasma source (MPS). Nitrogen was used as a working gas. All experimental tests were performed with the nitrogen flow rate Q ranged from 1500 to 3900 NL h

Cuprous Oxide Films Prepared by Using a Microwave Atmospheric Pressure Plasma Torch

2008 ◽  
Vol 47-50 ◽  
pp. 1015-1018 ◽  
Author(s):  
Hong Ying Chen ◽  
Lien Teng Kuo ◽  
Wan Yu Chang ◽  
Cheng Hsien Tsai
Keyword(s):  
Plasma Treatment ◽  
Cuprous Oxide ◽  
Atmospheric Pressure ◽  
Plasma Torch ◽  
Microwave Plasma ◽  
Cupric Oxide ◽  
Oxide Films ◽  
Atmospheric Pressure Plasma ◽  
Oxide Phase ◽  
Nitrogen Plasma

A 2.45 GHz microwave atmospheric pressure torch is employed to prepare cuprous oxide films. The sputtered copper films are firstly deposited on slide glass. After that, the films are annealed in air at 500°C for 12 h, which would directly oxidize into cupric oxide. The annealed films are then treated by atmospheric nitrogen plasma at 800 W for 10 min. The color changed significantly from black to reddish brown after nitrogen plasma treatment. The X-ray diffraction patterns show that annealed films are cupric oxide which is vanished after plasma treatment. The cuprous oxide films appeared after nitrogen plasma treatment. The resistivity of annealed films is 16.7 --cm, which reduce to 2.08 --cm after plasma treatment. The optical band gap of annealed films, cupric oxide phase, is 2.1 eV but the value shifts toward 2.4 eV after plasma treatment. The novel microwave plasma torch posses a fast and easy way to fabricate cuprous oxide films.

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