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 The Combination of Plasma-Processed Air (PPA) and Plasma-Treated Water (PTW) Causes Synergistic Inactivation of Candida albicans SC5314

2020 ◽  
Vol 10 (9) ◽  
pp. 3303 ◽  
Author(s):  
Uta Schnabel ◽  
Kateryna Yarova ◽  
Björn Zessin ◽  
Jörg Stachowiak ◽  
Jörg Ehlbeck
Keyword(s):  
Candida Albicans ◽  
Treatment Time ◽  
Synergistic Effects ◽  
Reduction Factor ◽  
Sample Treatment ◽  
Treated Water ◽  
Microwave Induced Plasma ◽  
Combined Application ◽  
Polymeric Surface ◽  
Strain Sc5314

Microwave-induced plasma was used for the generation of plasma-processed air (PPA) and plasma-treated water (PTW). By this way, the plasma was able to functionalize the compressed air and the used water to antimicrobial effective agents. Their fungicidal effects by single and combined application were investigated on Candida albicans strain SC5314. The monoculture of C. albicans was cultivated on specimens with polymeric surface structures (PE-stripes). The additive as well as the synergistic fungicidal potential of PPA and PTW was investigated by different process windows of plasma exposure time (5–50 s) and sample treatment time with PPA/PTW (1–5 min). For a single PTW or PPA treatment, an increase in the reduction factor with the indicated treatment time was observed (maximum reduction factor of 1.1 and 1.6, respectively). In comparison, the combined application of PTW and then PPA resulted in antagonistic, additive and synergistic effects, depending on the combination. An application of the synergistically acting processes of PTW for cleaning and PPA for drying can be an innovative alternative to the sanitary processes currently used in production plants.

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 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.

scholarly journals Adhesion between Epoxy Resin-Based Fiber Post and Dental Core Resin Improved by Non-Thermal Atmospheric Pressure Plasma

2020 ◽  
Vol 10 (7) ◽  
pp. 2535
Author(s):  
Hyoung-Sik Kim ◽  
Song-Yi Yang ◽  
Eun Ha Choi ◽  
Kwang-Mahn Kim ◽  
Jae-Sung Kwon
Keyword(s):  
Contact Angle ◽  
Bond Strength ◽  
Epoxy Resin ◽  
Atmospheric Pressure ◽  
Shear Bond Strength ◽  
Treatment Time ◽  
Atmospheric Pressure Plasma ◽  
Fiber Post ◽  
Pressure Plasma ◽  
Push Out

The purpose of the study was to evaluate the adhesion between dental core resin and epoxy resin-based fiber post after treatment with non-thermal atmospheric pressure plasma (NTAPP) and compare with conventional methods of epoxy resin-based fiber post treatments. Contact angle was measured on the surface of epoxy resin before and after NTAPP treatment and X-ray photoelectron spectroscopy was used to analyze the surface chemistry. Finally, two shear bond strength tests were carried out; shear bond strength between core resin and epoxy resin for comparison between NTAPP treated and untreated sample, and push-out shear bond strength between core resin and NTAPP treated commercially available epoxy resin-based fiber post for comparison between NTAPP treated samples with conventionally treated samples. Contact angle on the surface of epoxy resin generally decreased with increasing NTAPP treatment time with presence of surface chemical changes. Also, there was significantly higher shear bond strength and push-out shear bond strength between epoxy resin and core resin for NTAPP treated epoxy resin, even to the conventionally treated epoxy resin-based fiber post with hydrofluoric acid or silane. In conclusion, new technology of NTAPP has potential for application on the epoxy resin-based fiber post to improve endodontic restoration success rate.

Modeling the Inactivation of Bacillus cereus in Tiger Nut Milk Treated with Cold Atmospheric Pressure Plasma

2019 ◽  
Vol 82 (11) ◽  
pp. 1828-1836 ◽  
Author(s):  
ALIYU IDRIS MUHAMMAD ◽  
RUILING LV ◽  
XINYU LIAO ◽  
WEIJUN CHEN ◽  
DONGHONG LIU ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Atmospheric Pressure ◽  
Treatment Time ◽  
Atmospheric Pressure Plasma ◽  
Titratable Acidity ◽  
Weibull Model ◽  
Input Power ◽  
Inactivation Kinetics ◽  
Pressure Plasma ◽  
Cold Atmospheric Pressure Plasma

ABSTRACT The impact of cold atmospheric pressure plasma treatment on the inactivation kinetics of Bacillus cereus ATCC 14579 and the resulting quality changes was investigated in tiger nut (Cyperus esculentus L.) milk (TNM). The effect of input power (39, 43, and 46 W) and treatment time (0 to 270 s) was fitted using the Weibull model to represent the microbial kinetic inactivation in the treated TNM. Inactivation efficacy increased with an increase in treatment time and input power. A 5.28-log reduction was achieved at 39 to 46 W without significant changes in titratable acidity, whereas no reduction in titratable acidity was observed in the pasteurized sample. The inactivation kinetics was adequately described by the Weibull model. Higher input power of 43 and 46 W and 120 s of treatment resulted in marked decreases in pH, flavonoid concentration, and antioxidant activity compared with those parameters in pasteurized TNM. Increases in total color difference and phenolic concentrations also were observed. The results indicate that these changes were caused by the immanent plasma reactive species. This study provides valuable inactivation kinetics information for food safety assessment studies of B. cereus vegetative cells in TNM.

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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