Low-Pressure Microwave Plasma Sterilization of Polyethylene Terephthalate Bottles

A low-pressure microwave plasma reactor was developed for sterilization of polyethylene terephthalate (PET) bottles. In contrast to the established method using aseptic filling machines based on toxic sterilants, here a microwave plasma is ignited inside a bottle by using a gas mixture of nitrogen, oxygen, and hydrogen. To that effect, a reactor setup was developed based on a Plasmaline antenna allowing for plasma ignition inside three-dimensional packages. A treatment time below 5 s is provided for a reduction of 105 and 104 CFU of Bacillus atrophaeus and Aspergillus niger, respectively, verified by means of a count reduction test. The sterilization results obtained by means of this challenge test are in accordance with requirements for aseptic packaging machines as defined by the U.S. Food and Drug Administration and the German Engineering Federation. The plasma sterilization process developed here for aseptic filling of beverages is a dry process that avoids residues and the use of maximum allowable concentrations of established sterilants, e.g., hydrogen peroxide.

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Plasma Surface Modification of 316L Stainless Steel for Cardiovascular Stent Coating

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.89-91.196 ◽

2010 ◽

Vol 89-91 ◽

pp. 196-201 ◽

Cited By ~ 1

Author(s):

Enrico Gallino ◽

Michael Tatoulian ◽

Farzaneh Arefi-Khonsari ◽

D. Mantovani

Keyword(s):

Stainless Steel ◽

316L Stainless Steel ◽

Treatment Time ◽

Plasma Reactor ◽

Bare Metal Stent ◽

Metallic Surface ◽

Adhesive Properties ◽

Dry Process ◽

Biological Environment ◽

Stent Coating

Coronary stents are metallic (316L stainless steel) devices employed during balloon angioplasty to reopen and prevent the re-obstruction of a diseased narrowed area within a coronary artery. To reduce restenosis rate, bare metal stent coating is a promising solution. The coating can act as an anticorrosive barrier against the aggressive properties of biological environment, improving the long-term safety of the device. The goal of this study is to develop a dry process to isolate metallic surface from the biological environment by depositing a thin plasma polymerized allylamine (CH2=CH-CH2-NH2) film on the metallic surface. Plasma polymerized allylamine films were deposited on flat electropolished 316L stainless steel samples in a low pressure plasma reactor (70 kHz). Chemical composition of the coatings has been analysed as a function of the discharge power and treatment time. Moreover, special attention has been paid on the stability of the coating after immersion during 24 hours in D.I. water. Finally, to mimic stent expansion conditions, a “small punch test” has been used to investigate the adhesive properties of the coating. Our results demonstrate that is possible to deposit a stable, cohesive and adhesive plasma polymerized allylamine thin film which can be used as a coating for cardiovascular stents

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Construction of a Low-Pressure Microwave Plasma Reactor and Its Application in the Treatment of Volatile Organic Compounds

Environmental Science & Technology ◽

10.1021/es034697a ◽

2004 ◽

Vol 38 (13) ◽

pp. 3785-3791 ◽

Cited By ~ 13

Author(s):

Yet-Pole I ◽

Yung-Chuan Liu ◽

Kun-Yo Han ◽

Tien-Chai She

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Microwave Plasma ◽

Plasma Reactor ◽

Low Pressure ◽

Volatile Organic

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Properties of Waste Polyethylene Terephthalate (PET) Modified Asphalt Mixes: Dependence on PET Size, PET Content, and Mixing Process

Periodica Polytechnica Civil Engineering ◽

10.3311/ppci.10797 ◽

2018 ◽

Cited By ~ 5

Author(s):

Rajan Choudhary ◽

Abhinay Kumar ◽

Kishori Murkute

Keyword(s):

Experimental Design ◽

Polyethylene Terephthalate ◽

Volumetric Properties ◽

Mixing Process ◽

Moisture Susceptibility ◽

Asphalt Mixes ◽

Dry Process ◽

Modified Asphalt ◽

Pet Bottles ◽

Waste Polyethylene

Management and disposal of waste polyethylene terephthalate (PET) bottles is an ever-growing challenge. The present study investigated the effect of incorporation of shredded waste PET bottles on properties of asphalt mixes in terms of: (i) process of PET addition, (ii) PET content, and (iii) PET size. Experimental design included three variables: two processes (dry process, and modified dry process), three PET contents (2.5%, 5.0%, and 7.5% by weight of binder), and two PET sizes (2.36–1.18 mm, and 0.30–0.15 mm). Volumetric properties, Marshall parameters, and moisture susceptibility characteristics of PET modified mixes were evaluated and compared with control mix (without PET). Analysis of variance (ANOVA) was performed to evaluate main and interaction effects of the variables. Results indicated that all the three variables had significant influence on the measured properties. Further, mixes prepared using modified dry process outperformed other mixes and showed highest resistance towards moisture induced damage.

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Effect of Low-Pressure Plasma Treatment Parameters on Wrinkle Features

Materials ◽

10.3390/ma13173852 ◽

2020 ◽

Vol 13 (17) ◽

pp. 3852

Author(s):

Bongjun Gu ◽

Dongwook Ko ◽

Sungjin Jo ◽

Dong Choon Hyun ◽

Hyeon-Ju Oh ◽

...

Keyword(s):

Power Flow ◽

Treatment Time ◽

Argon Plasma ◽

Negative Ions ◽

Low Pressure ◽

Nitrogen Plasma ◽

Pressure Plasma ◽

Positive Ions ◽

Low Pressure Plasma ◽

Optical Adhesive

Wrinkles attract significant attention due to their ability to enhance the mechanical and optical characteristics of various optoelectronic devices. We report the effect of the plasma gas type, power, flow rate, and treatment time on the wrinkle features. When an optical adhesive was treated using a low-pressure plasma of oxygen, argon, and nitrogen, the oxygen and argon plasma generated wrinkles with the lowest and highest wavelengths, respectively. The increase in the power of the nitrogen and oxygen plasma increased the wavelengths and heights of the wrinkles; however, the increase in the power of the argon plasma increased the wavelengths and decreased the heights of the wrinkles. Argon molecules are heavier and smaller than nitrogen and oxygen molecules that have similar weights and sizes; moreover, the argon plasma comprises positive ions while the oxygen and nitrogen plasma comprise negative ions. This resulted in differences in the wrinkle features. It was concluded that a combination of different plasma gases could achieve exclusive control over either the wavelength or the height and allow a thorough analysis of the correlation between the wrinkle features and the characteristics of the electronic devices.

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Investigation of Pressure Oscillation and Cavitation Characteristics for Submerged Self-Resonating Waterjet

Applied Sciences ◽

10.3390/app11156972 ◽

2021 ◽

Vol 11 (15) ◽

pp. 6972

Author(s):

Lihua Cui ◽

Fei Ma ◽

Tengfei Cai

Keyword(s):

Sudden Change ◽

Three Dimensional ◽

Pressure Oscillation ◽

Experimental Tests ◽

Low Pressure ◽

The Self ◽

Two Phase ◽

Cavitation Phenomenon ◽

Pressure Zone ◽

Unsteady Characteristics

The cavitation phenomenon of the self-resonating waterjet for the modulation of erosion characteristics is investigated in this paper. A three-dimensional computational fluid dynamics (CFD) model was developed to analyze the unsteady characteristics of the self-resonating jet. The numerical model employs the mixture two-phase model, coupling the realizable turbulence model and Schnerr–Sauer cavitation model. Collected data from experimental tests were used to validate the model. Results of numerical simulations and experimental data frequency bands obtained by the Fast Fourier transform (FFT) method were in very good agreement. For better understanding the physical phenomena, the velocity, the pressure distributions, and the cavitation characteristics were investigated. The obtained results show that the sudden change of the flow velocity at the outlet of the nozzle leads to the forms of the low-pressure zone. When the pressure at the low-pressure zone is lower than the vapor pressure, the cavitation occurs. The flow field structure of the waterjet can be directly perceived through simulation, which can provide theoretical support for realizing the modulation of the erosion characteristics, optimizing nozzle structure.

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Design of an Intermediate Turbine Duct Downstream of a High Pressure Turbine

Volume 2A: Turbomachinery ◽

10.1115/gt2016-56476 ◽

2016 ◽

Author(s):

Chaoshan Hou ◽

Hu Wu

Keyword(s):

High Pressure ◽

Three Dimensional ◽

Low Pressure ◽

Aerodynamic Load ◽

Duct Flow ◽

Original Design ◽

High Pressure Turbine ◽

Intermediate Turbine Duct ◽

Low Pressure Turbine ◽

Inlet Conditions

The flow leaving the high pressure turbine should be guided to the low pressure turbine by an annular diffuser, which is called as the intermediate turbine duct. Flow separation, which would result in secondary flow and cause great flow loss, is easily induced by the negative pressure gradient inside the duct. And such non-uniform flow field would also affect the inlet conditions of the low pressure turbine, resulting in efficiency reduction of low pressure turbine. Highly efficient intermediate turbine duct cannot be designed without considering the effects of the rotating row of the high pressure turbine. A typical turbine model is simulated by commercial computational fluid dynamics method. This model is used to validate the accuracy and reliability of the selected numerical method by comparing the numerical results with the experimental results. An intermediate turbine duct with eight struts has been designed initially downstream of an existing high pressure turbine. On the basis of the original design, the main purpose of this paper is to reduce the net aerodynamic load on the strut surface and thus minimize the overall duct loss. Full three-dimensional inverse method is applied to the redesign of the struts. It is revealed that the duct with new struts after inverse design has an improved performance as compared with the original one.

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Detoxification of Trichloroethylene in a Low-Pressure Surface Wave Plasma Reactor

Environmental Science & Technology ◽

10.1021/es950343a ◽

1996 ◽

Vol 30 (8) ◽

pp. 2427-2431 ◽

Cited By ~ 15

Author(s):

Josep Arnó ◽

John W. Bevan ◽

Michel Moisan

Keyword(s):

Surface Wave ◽

Plasma Reactor ◽

Low Pressure ◽

Pressure Surface

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The Modification of Carbon Included Polyethylene Surface by Plasma Treatment for Metallizing Using a Low Pressure RF Discharge Plasma

Journal of Advanced Oxidation Technologies ◽

10.1515/jaots-2005-0111 ◽

2005 ◽

Vol 8 (1) ◽

Author(s):

Jeou-Long Lee ◽

Chung-Ming Liu ◽

Kuen Ting ◽

Wei-Kung Cheng ◽

Takayoshi Tsuchida ◽

...

Keyword(s):

Surface Roughness ◽

Contact Angle ◽

Surface Layer ◽

Discharge Plasma ◽

Treatment Time ◽

Low Pressure ◽

Rf Discharge ◽

Nickel Layer ◽

Good Adhesion ◽

Polyethylene Surface

AbstractSurface modification of the carbon included polyethylene (semi-conductive PE) surface for metallizing using a low pressure RF discharge plasma has been carried out. The contact angle was used as a measure of the wettability of the PE surface. The roughness and the chemical bondings in PE surface layer were analized by DFM and XPS, respectively. Typical results show that the contact angle decreases from approximately 94° to below 10° after several minutes' treatment and recovers to a saturation value when it was put open to the air after treatment. The saturation value of the contact angle is smaller as the gas pressure for treatment is higher and the treatment time is longer but all are below approximately 60° which is still smaller than that of untreated. DFM and XPS results show that the surface roughness and the bondings C-O and C=O in the PE surface layer also increase with increasing the treatment time and seem to be responsible for improving the hydrophilic property of PE. After pretreatment process, nickel was coated on the PE sheet by electrodeposition method and a good adhesion between the nickel layer and the PE surface compared with that of untreated was obtained.

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