Energy coupling efficiency of a hydrogen microwave plasma reactor

2001 ◽  
Vol 89 (3) ◽  
pp. 1544 ◽  
Author(s):  
M. H. Gordon ◽  
X. Duten ◽  
K. Hassouni ◽  
A. Gicquel
Keyword(s):  
Microwave Plasma ◽  
Plasma Reactor ◽  
Coupling Efficiency ◽  
Energy Coupling

Transcriptome response to different carbon sources in Acetobacter aceti

Microbiology ◽  
2011 ◽  
Vol 157 (3) ◽  
pp. 899-910 ◽  
Author(s):  
Kenta Sakurai ◽  
Hiroyuki Arai ◽  
Masaharu Ishii ◽  
Yasuo Igarashi
Keyword(s):  
Draft Genome ◽  
Coupling Efficiency ◽  
Tca Cycle ◽  
Energy Coupling ◽  
Proton Pumping ◽  
Type I ◽  
Acetobacter Aceti ◽  
Expression Levels ◽  
Glyoxylate Pathway ◽  
In Cells

The draft genome sequence of Acetobacter aceti NBRC 14818 was determined by whole-genome shotgun sequencing and the transcriptome profile in cells exponentially grown on ethanol, acetate or glucose was analysed by using a DNA microarray. The genes for all enzymes that constitute the complete tricarboxylic acid (TCA) cycle and glyoxylate pathway were identified in the genome. The TCA cycle genes showed higher expression levels in A. aceti cells grown on acetate or glucose and the glyoxylate pathway genes were significantly induced by ethanol or acetate. Many SOS-response genes were upregulated in cells grown on ethanol, indicating that ethanol provoked damage of DNA and proteins. The superoxide dismutase and catalase genes showed high expression levels in culture on glucose, indicating that oxidation of glucose induced oxidative stress. A. aceti NBRC 14818 was found to have a highly branched respiratory chain. The genes for two type I and one type II NADH dehydrogenase were identified. The genes for one of the type I enzymes were highly expressed when cells were grown on acetate or glucose, but were significantly downregulated in culture on ethanol, probably because ubiquinones were directly reduced by pyrroloquinoline quinone-dependent alcohol dehydrogenase. Four sets of the genes for quinol oxidases, one bo 3-type (BO3), one bd-type and two cyanide-insensitive-types (CIOs), were identified in the genome. The genes for BO3, which might have proton-pumping activity, were highly expressed under the conditions tested, but were downregulated in the glucose culture. In contrast, the genes for one of the CIOs were significantly upregulated in cells grown on glucose. The two CIOs, which are expected to have lower energy-coupling efficiency, seemed to have a higher contribution in glucose-grown cells. These results indicate that energy conservation efficiency is fine-tuned by changing the respiratory components according to the growth conditions in A. aceti cells.

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

Nanoparticles generated by combining hot wall and microwave plasma chemical vapor synthesis

MRS Advances ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 213-218
Author(s):  
Alexander Levish ◽  
Markus Winterer
Keyword(s):  
Iron Oxide ◽  
Microwave Plasma ◽  
Plasma Reactor ◽  
Chemical Vapor ◽  
Process Window ◽  
Chemical Vapor Synthesis ◽  
Second Stage ◽  
Structure Surface ◽  
Oxide Phases ◽  
Precursor Decomposition

ABSTRACTControlling the oxidation state of iron and the crystal structure of iron containing compounds is the key to improved materials such as iron oxide nanoparticles for cancer treatment or heterogeneous catalysis. Iron oxides contain iron in different oxidation states and form different phases for one valence state (α-Fe3+2O2-3, β- Fe3+2O-32, etc.). Chemical vapor synthesis (CVS) allows the reproducible production of pure nanocrystals with narrow size distribution where particle formation and growth take place in the gas phase. Through the controlled variation of synthesis parameters CVS enables the synthesis of diverse iron oxide phases. In this study the energy for the CVS process is supplied by a hot wall furnace and a microwave plasma. The advantage of an plasma reactor as the first CVS stage is the fast and complete precursor decomposition at low temperatures. This results in a larger process window for the hot wall reactor in the second stage. The nanoparticles are examined regarding their structure, surface and valence by XRD and TEM.

scholarly journals Composition, Mixing State and Water Affinity of Meteoric Smoke Analogue Nanoparticles Produced in a Non-Thermal Microwave Plasma Source

2018 ◽  
Vol 232 (5-6) ◽  
pp. 635-648 ◽  
Author(s):  
Mario Nachbar ◽  
Denis Duft ◽  
Alexei Kiselev ◽  
Thomas Leisner
Keyword(s):  
Silicon Oxide ◽  
Microwave Plasma ◽  
Plasma Reactor ◽  
Stoichiometric Composition ◽  
Plasma Source ◽  
Mixing State ◽  
Iron Oxide Particles ◽  
Pure Silicon ◽  
Meteoric Smoke ◽  
Water Affinity

Abstract The article reports on the composition, mixing state and water affinity of iron silicate particles which were produced in a non-thermal low-pressure microwave plasma reactor. The particles are intended to be used as meteoric smoke particle analogues. We used the organometallic precursors ferrocene (Fe(C5H5)2) and tetraethyl orthosilicate (TEOS, Si(OC2H5)4) in various mixing ratios to produce nanoparticles with radii between 1 nm and 4 nm. The nanoparticles were deposited on sample grids and their stoichiometric composition was analyzed in an electron microscope using energy dispersive X-ray spectroscopy (EDS). We show that the pure silicon oxide and iron oxide particles consist of SiO2 and Fe2O3, respectively. For Fe:(Fe+Si) ratios between 0.2 and 0.8 our reactor produces (in contrast to other particle sources) mixed iron silicates with a stoichiometric composition according to FexSi(1−x)O3 (0≤x≤1). This indicates that the particles are formed by polymerization of FeO3 and SiO3 and that rearrangement to the more stable silicates ferrosilite (FeSiO3) and fayalite (Fe2SiO4) does not occur at these conditions. To investigate the internal mixing state of the particles, the H2O surface desorption energy of the particles was measured. We found that the nanoparticles are internally mixed and that differential coating resulting in a core-shell structure does not occur.

Numerical Simulation of Gas Phase Growth Environment of Carbon Nanotube Synthesis by Plasma-Enhanced Chemical Vapor Deposition

2005 ◽  
Author(s):  
R. K. Garg ◽  
J. P. Gore ◽  
T. S. Fisher
Keyword(s):  
Gas Phase ◽  
Reaction Mechanisms ◽  
Microwave Plasma ◽  
Plasma Reactor ◽  
Chemical Vapor ◽  
Synthesis Process ◽  
Phase Reaction ◽  
Phase Growth ◽  
Growth Environment ◽  
Hydrogen Mixture

The gas-phase growth environment of carbon nanotubes has been simulated using different published chemical reaction mechanisms for a gas mixture of methane and hydrogen. Detailed chemical analysis of the growth environment is important in identifying precursor species responsible for CNT formation and is useful in understanding fundamental mechanisms that ultimately could allow control of the CNT synthesis process. The present simulations seek to compare the roles of different gas phase reaction mechanisms and to identify precursors for CNT formation. The results show that inlet methane-hydrogen mixture converts primarily to a acetylene-hydrogen mixture, and C2H2, CH3, H2, and H are the main precursors formed in the plasma under experimentally verified CNT growth conditions in a microwave plasma reactor.

scholarly journals Microwave Plasma System for Continuous Treatment of Railway Track

Technologies ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 54
Author(s):  
Julian Swan ◽  
Marilena Radoiu
Keyword(s):  
Microwave Plasma ◽  
Plasma Reactor ◽  
Network Capacity ◽  
Atmospheric Plasma ◽  
Continuous Treatment ◽  
Railway Track ◽  
Microwave Cavity ◽  
Limiting Factor ◽  
Plasma System ◽  
Autumn Season

Braking conditions are a fundamental issue for the railway and have been a limiting factor in network capacity and timetabling. Leaf fall, especially during the autumn season, creates low-adhesion problems on railways, causing braking problems for trains. To address the requirements of the novel plasma industrial applications towards environmental applications, this work developed and tested a 2.45 GHz microwave atmospheric pressure plasma system for in situ removal of the third body layer deposited onto the railway so as to improve braking. The plasma reactor consisted of a 15 kW, 2.45 GHz magnetron-based microwave generator and a plasma reactor (dielectric tube placed in a TE01 monomode microwave cavity); the atmospheric plasma ignited and sustained at different power levels (2–15 kW) in different gases (nitrogen, argon) as well as mixtures of these gases with reactive molecules (water, oxygen) was jetted directly onto the railhead as to change the conditions for the wheel–rail interface. This technology is hoped to be a game-changer in enabling predictable and optimized braking on the railway network. Challenges encountered during the demonstration phase are discussed. Subsequent work should validate the results on a working railway line during the autumn season.

Characterization and Tribological Properties of Nanostructured Copper/Carbon Composite Films Prepared by Microwave Plasma-Assisted Dual Deposition Processes

2002 ◽  
Vol 750 ◽  
Author(s):  
François Thiery ◽  
Yves Pauleau ◽  
Jacques Pelletier
Keyword(s):  
Amorphous Carbon ◽  
Electron Cyclotron Resonance ◽  
Microwave Plasma ◽  
Plasma Reactor ◽  
Composite Films ◽  
Chemical Vapor ◽  
Carbon Matrix ◽  
Carbon Composite ◽  
Carbon Films ◽  
Radius Of Curvature

ABSTRACTNanocrystalline copper/hydrogenated amorphous carbon films have been deposited on Si substrates at the floating potential using a distributed electron cyclotron resonance microwave plasma reactor. In this deposition technique, the microwave plasma-enhanced chemical vapor deposition process of carbon from argon-methane or argon-acetylene mixtures of various compositions was associated with the sputter deposition of copper from a copper target. The total pressure was fixed at 0.13 Pa. For deposition, the substrates mounted on a water-cooled substrate holder were maintained at ambient temperature. The composition of films determined by Rutherford backscattering spectroscopy, energy recoil detection analyses and nuclear reaction analyses was investigated as a function of the gas phase composition. The structure of films was identified by X-ray diffraction (XRD) techniques and the size of copper crystallites incorporated in the amorphous carbon matrix was deduced from XRD data. The magnitude of residual stresses developed in these films was calculated from the radius of curvature of film/substrate samples determined by profilometry. The residual stress values were found to be nearly independent on the composition of films and deposition parameters.

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