scholarly journals The Assessment of Carbon Dioxide Dissociation Using a Single-Mode Microwave Plasma Generator

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1558 ◽  
Author(s):  
George Mogildea ◽  
Marian Mogildea ◽  
Cristina Popa ◽  
Gabriel Chiritoi
Keyword(s):  
Carbon Dioxide ◽  
Microwave Plasma ◽  
Focal Point ◽  
Single Mode ◽  
Plasma Generator ◽  
High Energy ◽  
High Electron ◽  
Space Applications ◽  
Plasma Characterization ◽  
Co2 Atmosphere

This paper focuses on the dissociation of carbon dioxide (CO2) following the absorption processes of microwave radiation by noncontact metal wire (tungsten). Using a microwave plasma generator (MPG) with a single-mode cavity, we conducted an interaction of microwaves with a noncontact electrode in a CO2 atmosphere. High energy levels of electromagnetic radiation are generated in the focal point of the MPG’s cylindrical cavity. The metal wires are vaporized and ionized from this area, subsequently affecting the dissociation of CO2. The CO2 dissociation is highlighted through plasma characterization and carbon monoxide (CO) quantity determination. For plasma characterization, we used an optical emission spectroscopy method (OES), and for CO quantity determination, we used a gas analyzer instrument. Using an MPG in the CO2 atmosphere, we obtained a high electron temperature of the plasma and a strong dissociation of CO2. After 20 s of the interaction between microwaves and noncontact electrodes, the quantity of CO increased from 3 ppm to 1377 ppm (0.13% CO). This method can be used in space applications to dissociate CO2 and refresh the atmosphere of closed spaces.

scholarly journals The Assessment of Carbon Dioxide Dissociation Using Single Mode Microwave Plasma Generator

2020 ◽  
Author(s):  
George Mogildea ◽  
Marian Mogildea ◽  
Cristina Popa ◽  
Gabriel Chiritoi
Keyword(s):  
Carbon Dioxide ◽  
Electron Temperature ◽  
Cylindrical Cavity ◽  
Microwave Plasma ◽  
Focal Point ◽  
Plasma Generator ◽  
High Energy ◽  
High Electron ◽  
High Definition ◽  
Metallic Wires

The paper focuses of the interaction between tungsten (W) wire and microwave field in carbon dioxide (CO2) atmosphere. Our experimental set-up uses a microwave plasma generator in order to generate the plasma from the metallic wires. The microwave plasma generator contain a cylindrical cavity - TM_011 propagation modes, commercial source (magnetron) having the 2.45 GHz frequency at 800 W microwave and power supply. In the focal point of the cylindrical cavity we have a high energy of the electromagnetic radiation. The metallic wires from this area will be vaporized and ionized having as effect CO2 dissociation. The electron temperature regarding metallic plasma produced was estimated using the ratio of atomic emission lines acquired by a high definition of the optical multichannel spectrometer. Determination of the CO2 dissociation quantity was estimated measuring of the carbon monoxide (CO) resulting of the CO2 dissociation process. We obtained a high electron temperature of the plasma and a strong dissociation of the CO2.

The Effect of Flame Temperature, Nozzle Position and Swirl Gas on Microwave Plasma Flame

2014 ◽  
Vol 68 (3) ◽  
Author(s):  
Pang Zhen Ann ◽  
Norasyikin Ismail ◽  
Farid Nasir Ani
Keyword(s):  
Microwave Plasma ◽  
Flame Temperature ◽  
Combustion Process ◽  
Single Mode ◽  
Plasma Generator ◽  
Vertical Position ◽  
Plasma Flame ◽  
Flame Burner ◽  
Nozzle Position ◽  
Quartz Nozzle

In this study, a microwave plasma generator was used to develop a plasma flame. The effects of microwave plasma on flame temperature, nozzle position and swirl gas were investigated. A microwave generator with 1kW power was used to generate a single mode microwave in the wave guide and passes through a flame burner. The study show that the flame temperature increased when the microwave power was increased. This is due to absorption of energy from the microwave. The optimum position of the quartz nozzle when generating plasma was located one quarter of wavelength away from the end of the waveguide. This was the optimum location of the nozzle because the intensity of electric field was the strongest at this point. The vertical position of the quartz nozzle does not affect the plasma formation. Compressed air was used as swirl gas to create a swirling effect that stabilized the plasma flame. The swirl gas does not shield the quartz reactor from the flame but enlarging the size of the flame. This is due to swirl gas which contains oxygen acts as oxidant which supplies oxygen to the combustion process.

scholarly journals Focused VHEE (very high energy electron) beams and dose delivery for radiotherapy applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
L. Whitmore ◽  
R. I. Mackay ◽  
M. van Herk ◽  
J. K. Jones ◽  
R. M. Jones
Keyword(s):  
Electron Beams ◽  
Focal Point ◽  
External Beam Radiotherapy ◽  
High Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Dose Delivery ◽  
Entrance Dose ◽  
Very High Energy ◽  
Very High

AbstractThis paper presents the first demonstration of deeply penetrating dose delivery using focused very high energy electron (VHEE) beams using quadrupole magnets in Monte Carlo simulations. We show that the focal point is readily modified by linearly changing the quadrupole magnet strength only. We also present a weighted sum of focused electron beams to form a spread-out electron peak (SOEP) over a target region. This has a significantly reduced entrance dose compared to a proton-based spread-out Bragg peak (SOBP). Very high energy electron (VHEE) beams are an exciting prospect in external beam radiotherapy. VHEEs are less sensitive to inhomogeneities than proton and photon beams, have a deep dose reach and could potentially be used to deliver FLASH radiotherapy. The dose distributions of unfocused VHEE produce high entrance and exit doses compared to other radiotherapy modalities unless focusing is employed, and in this case the entrance dose is considerably improved over existing radiations. We have investigated both symmetric and asymmetric focusing as well as focusing with a range of beam energies.

Laser Ignition of Surgical Drape Materials in Air, 50% Oxygen, and 95% Oxygen

2004 ◽  
Vol 100 (5) ◽  
pp. 1167-1171 ◽  
Author(s):  
Gerald L. Wolf ◽  
George W. Sidebotham ◽  
Jackson L. P. Lazard ◽  
Jean G. Charchaflieh
Keyword(s):  
Carbon Dioxide ◽  
Operating Room ◽  
Oxygen Concentration ◽  
High Energy ◽  
Ignition Source ◽  
Laser Ignition ◽  
Surgical Tools ◽  
Time To Ignition ◽  
Room Fires ◽  
Surgical Laser

Background Operating room fires fueled by surgical drapes and ignited by high-energy surgical tools in air and oxygen-enriched atmospheres continue to occur. Methods The authors examined the time to ignition of huck towels and three commonly used surgical drape materials in air, 50% oxygen, and 95% oxygen using a carbon dioxide surgical laser as an ignition source. In addition, a phenol-polymer fabric was tested. Results In air, polypropylene and phenol polymer do not ignite. For polypropylene, the laser instantly vaporized a hole, and therefore, interaction between the laser and material ceased. When tested in combination with another material, the polypropylene time to ignition assumed the behavior of the material with which it was combined. For phenol polymer, the laser did not penetrate the material. Huck towels, cotton-polyester, and non-woven cellulose-polyester ignited in air with decreasing times to ignition. All tested materials ignited in 50% and 95% oxygen. Conclusion The results of this study reveal that with increasing oxygen concentration, the time to ignition becomes shorter, and the consequences become more severe. The possibility exists for manufacturers to develop drape materials that are safer than existing materials.

Investigation of Dielectric Resonator Oscillator Using High-Electron Mobility Transistor at 26GHz for Space Applications

2021 ◽  
pp. 2250046
Author(s):  
Pinku Ranjan ◽  
Swati Khandare
Keyword(s):  
Phase Noise ◽  
Electron Mobility ◽  
Dielectric Resonator ◽  
High Electron Mobility Transistor ◽  
Low Noise ◽  
Design System ◽  
High Electron ◽  
Space Applications ◽  
High Electron Mobility ◽  
High Frequencies

An oscillator is a vital component as the energy source in microwave telecommunication system. Microwave oscillators designed using Gunn diode have poor DC to RF efficiency. IMPact Ionization Avalanche Transit-Time diode (IMPATT) oscillators have the drawback of poor noise performance. The transistorized oscillators have a limitation to the maximum oscillation frequency which means that they cannot be used for oscillators designed for high frequencies. To design negative series feedback Dielectric Resonator Oscillator (DRO), the resonant unit uses a dielectric resonator (DR) since it is small in size, light in weight, has high-Quality ([Formula: see text]) factor, better stability and also it is inexpensive. It has the benefits of low-phase noise, low cost, miniaturization, high stability, applicable for devices designed at high frequencies and had already been widely applied, so the research on microwave dielectric oscillator has also been one of the focus of today’s microwave integrated circuits. DRO is widely used in electronic warfare, missile, radar and communication systems. The DRO incorporates High-Electron Mobility Transistor (HEMT) as an active device since it offers higher power-added efficiency combined with excellent low-noise figures and performance. The entire circuit of DRO using HEMT at 26[Formula: see text]GHz is designed using Agilent Advanced Design System (ADS) software. In this, DRO different measurements of parameters are done such as output power which is typically [Formula: see text][Formula: see text]dBm for 26[Formula: see text]GHz DRO, phase noise at 10[Formula: see text]kHz offset for 26[Formula: see text]GHz DRO it is 80[Formula: see text]dBc/Hz. The frequency pushing and frequency pulling for 26[Formula: see text]GHz DRO its typical values are 30[Formula: see text]kHz/V and 1[Formula: see text]MHz, respectively.

Analyzing the impact of fossil fuel import reliance on electricity prices: The case of the Iberian Electricity Market

2017 ◽  
Vol 28 (7) ◽  
pp. 687-705 ◽  
Author(s):  
Blanca Moreno ◽  
María T García-Álvarez
Keyword(s):  
Carbon Dioxide ◽  
Electricity Market ◽  
Fossil Fuel ◽  
Carbon Dioxide Emission ◽  
High Energy ◽  
Electricity Production ◽  
The European Union ◽  
Electricity Prices ◽  
The Impact ◽  
The Eu

Spain and Portugal are highly dependent on energy from abroad, importing more than 70% of all the energy they consume. This high energy dependence could involve important effects on the level and stability of their electricity prices as a half the gross electricity generated in both countries came from power stations using imported combustible fuels (such as natural gas, coal and oil). In general, changes in the prices of these fossil fuels can directly affect household electricity prices, since generation costs are likely to be transmitted through to the wholesale electricity market. Moreover, in the framework of the European Union Emission Trading System, electricity production technologies tend to incorporate their costs of carbon dioxide emission allowances in sale offers with the consequent increase of the electricity prices. The objective of this paper is to analyze the influence of fossil fuel costs and prices of carbon dioxide emission allowances in the EU on the Spanish and Portuguese electricity prices. With this aim, a maximum entropy econometric approach is used. The obtained results indicate that not only the price of imported gas are very important in explaining Spanish and Portuguese electricity prices but also the price of carbon dioxide emission allowances in the EU.

scholarly journals Design and characterization of an electromagnetic-resonant cavity microwave plasma reactor for atmospheric pressure carbon dioxide decomposition

2018 ◽  
Vol 16 (2) ◽  
pp. 1800153 ◽  
Author(s):  
Sina Mohsenian ◽  
Shyam Sheth ◽  
Saroj Bhatta ◽  
Dassou Nagassou ◽  
Daniel Sullivan ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Pressure ◽  
Microwave Plasma ◽  
Plasma Reactor ◽  
Resonant Cavity
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